Laser irradiation apparatus, laser irradiation method, and method for manufacturing semiconductor device

Laser irradiation device, laser irradiation method, and manufacturing method of semiconductor device

The present invention relates to a laser irradiation device used for crystallization of a semiconductor film. In addition, the present invention relates to a laser irradiation method using a laser irradiation device and a manufacturing method of a semiconductor device.

Thin-film transistors (polysilicon TFTs) using polycrystalline semiconductor films have a mobility of more than two digits higher than TFTs using amorphous semiconductor films. Therefore, polycrystalline silicon TFTs have the ability to form semiconductor display devices on the same substrate. The advantages of the pixel portion and the surrounding drive circuit. The polycrystalline semiconductor film can be formed on an inexpensive glass substrate by using a laser annealing process.

According to its oscillation method, lasers are roughly divided into two types: pulse oscillation and continuous oscillation. Compared with the continuously oscillating laser represented by the excimer laser, the laser output energy per unit time is about 3~6 bits higher. Therefore, it is possible to use the optical system to form the beam spot (the area where the laser is actually irradiated on the surface of the processed object) into a rectangular shape with a few centimeters or a linear shape with a length of 100 mm or more, and the semiconductor film can be efficiently processed. Laser irradiation improves productivity. Therefore, in the crystallization of semiconductor films, the use of pulsed lasers has gradually become the mainstream.

In addition, the term "linear" here is not a "line" in the strict sense, but a rectangle (or oblong) with a large aspect ratio. For example, although an aspect ratio of 2 or more (preferably 10 to 10000) is called a linear shape, the linear shape belongs to a rectangular shape.

However, a semiconductor film crystallized using a pulsed oscillation laser in this way is formed by a collection of a plurality of crystal grains whose positions and sizes are irregular. Compared with the inner side of the crystal grains, there are countless amorphous structures or recombination centers or trapping centers due to crystal defects and the like on the crystal grain boundary surfaces (crystal grain boundaries). When the carrier is trapped at the trapping center, the potential of the crystal grain boundary rises to form an obstacle to the carrier, so there is a problem that the transport characteristic of the carrier is lowered.

In view of the above-mentioned problems, the technology of using a continuously oscillating laser to crystallize a semiconductor film has attracted much attention in recent years. In the case of using a continuously oscillating laser, unlike conventional pulsed lasers, by irradiating the semiconductor film while scanning the continuously oscillating laser in one direction, the crystal faces continuously in the scanning direction. By growing, it is possible to form a group of crystal grains composed of single crystals elongated in the scanning direction. It is generally believed that by using the above method, a semiconductor film having almost no crystal grain boundaries can be formed at least in the direction crossing the channel of the TFT.

Moreover, when crystallization of the semiconductor film, the larger the laser absorption coefficient of the semiconductor film, the more effectively the semiconductor film can be crystallized. When using YAG laser or YVO₄When laser crystallization is usually used for silicon films with a thickness of tens to hundreds of nm in semiconductor devices, since the second harmonic with a short wavelength has a much higher absorption coefficient than the fundamental wave, harmonics are usually used for crystallization. Chemical process, and almost no fundamental wave is used. Non-linear optical elements can be used to convert fundamental waves into harmonics.

However, when a continuously oscillating laser is used, a load is continuously applied to the non-linear optical element, so there is a problem that the resistance of the non-linear optical element to the laser is significantly reduced compared to when using a pulsed oscillating laser. In addition, compared with pulsed oscillating lasers, continuous oscillating lasers have low energy of the laser beam output per unit time, so the photon density with respect to time is low, so the conversion performed in the non-linear optical element The conversion efficiency for harmonics is low. Specifically, although it varies with the characteristic or time characteristic of the incident light, the conversion efficiency of a pulsed laser is generally 10-30%, and the conversion efficiency of a continuous-oscillation laser is generally 0.2-0.3%.

According to this, compared with a pulsed laser, a laser with harmonics has a lower output energy per unit time, so it is difficult to expand the area of the beam spot to improve productivity. For example, a continuously oscillating YAG laser can output a fundamental wave of 10kW, but it can only obtain energy of the second harmonic of about 10W. In this case, in order to obtain the necessary energy density for the crystallized semiconductor film, the beam spot area must be reduced to 10^-3mm²about. In this way, the productivity of a continuously oscillating laser is inferior to that of a pulsed excimer laser, and this becomes a reason for lowering the economy in mass production.

In addition, at both ends of the beam spot in a direction perpendicular to the scanning direction, the crystal grains are significantly smaller than the center of the beam spot, and regions with poor crystallinity are formed. Even if a semiconductor element is formed in the region with poor crystallinity, the semiconductor element cannot be expected to have high characteristics. Moreover, there are limits to the method of reducing the crystallite formation area only by adjusting the optical system. Therefore, in order to alleviate the constraints on the layout of semiconductor elements, it is important to enlarge the width of the beam spot in the vertical direction with respect to the scanning direction. However, it is difficult for a continuously oscillating laser to enlarge the beam spot area due to the above-mentioned reasons, so the beam spot amplitude is also smaller than that of a pulsed laser beam, which makes the above-mentioned semiconductor device layout restrictions more stringent.

In addition, although the use of a continuously oscillating laser can form a thermodynamically non-equilibrium state, compared to a pulsed oscillating laser, a peak power of several MW or more can be obtained, and the continuous oscillation is about several kW, and the output energy is low. Therefore, even if it can be in an unbalanced state, when laser annealing the semiconductor film on the glass substrate, the continuously oscillating laser causes more thermal damage to the glass substrate than the pulsed oscillating laser, which is not suitable. In addition, if the thermal damage is significant, it may cause the problem of shrinkage of the light-emitting area.

In view of the above problems, the object of the present invention is to provide a laser irradiation device, which can greatly expand the beam spot area compared with a continuously oscillating laser, and suppress thermal damage to the glass substrate, and can crystallize The face continuously grows in the scanning direction, forming a group of crystal grains composed of single crystals elongated in the scanning direction. Moreover, the object of the present invention is to provide a laser irradiation device capable of suppressing the degradation of the nonlinear optical element and obtaining a higher-energy laser beam. Furthermore, an object of the present invention is to provide a laser irradiation method using the laser irradiation device and a method of manufacturing a semiconductor device.

The inventors of the present invention considered that even if a pulsed laser is used, during the period of the semiconductor film from being melted by the laser beam to solidifying, by oscillating the laser beam at a pulse repetition frequency that can irradiate the next pulsed laser beam, It is possible to obtain crystal grains that continuously grow facing the scanning direction. That is, in the present invention, the lower limit of the pulse repetition frequency is determined on the premise that the pulse period is made shorter than the time from melting to complete solidification of the semiconductor film.

In fact, the pulse repetition frequency of the pulsed laser used in the present invention is 10 MHz or higher, which uses a frequency band much higher than the frequency band of tens to hundreds of Hz used by the usual pulsed laser. It is known that the time from irradiating the laser beam to the semiconductor film with pulse oscillation to the complete curing of the semiconductor film is from tens of nsec to hundreds of nsec. Therefore, the present invention utilizes the above frequency band, during the period between the semiconductor film is melted by the laser beam and solidified. , Illuminate the next laser beam. According to this, unlike the case of a conventional pulsed laser, since the solid-liquid interface can be continuously moved in the semiconductor film, a semiconductor film having crystal grains that continuously grow facing the scanning direction is formed. Specifically, it is possible to form a collective of crystal grains whose width in the scanning direction of the contained crystal grains is 10 to 30 μm, and the width in the vertical direction with respect to the scanning direction is about 1 to 5 μm. By forming single crystal grains elongated in the scanning direction, it is possible to form a semiconductor film with almost no grain boundaries at least in the TFT channel direction.

In addition, when a conventional pulsed laser is used to perform crystallization of a semiconductor film, impurities such as oxygen, nitrogen, and carbon tend to segregate in the crystal grain boundaries. Especially in the case of combining a crystallization method using a laser and a crystallization method using a catalyst metal, the catalyst metal that has not been completely removed may segregate. In the present invention, since the solid-liquid interface can be continuously moved in the semiconductor film, the same as the zone melting method, the segregation of impurities with a positive segregation coefficient can be prevented, and the purification of the semiconductor film and the uniformization of the solute concentration can be performed . Thereby, the characteristics of the semiconductor element using the semiconductor film can be improved, and the unevenness of the characteristics between the elements can be suppressed.

In addition, when a continuously oscillating laser is used, the time for irradiating the laser beam to any point on the semiconductor film is in the order of 10 μsec. However, in the present invention, because the laser beam is oscillated at a high pulse repetition frequency exceeding 10 MHz, the pulse width is 1 nsec or less, so that the time for irradiating light to each point can be 10 times that of a continuous oscillation laser.⁴Moreover, compared with a continuously oscillating laser, it can also significantly increase the peak power. Therefore, in the present invention, when the semiconductor film formed on the substrate is crystallized, compared with a continuously oscillating laser, the heat applied to the substrate can be greatly suppressed, thereby preventing the shrinkage of the substrate and preventing impurities from other The film diffuses into the semiconductor film, and therefore, the characteristics and yield of the semiconductor element can be improved.

In addition, according to the present invention, in the case of using a pulse repetition frequency much higher than conventional, the pulse width is inevitably shortened to the order of psec in accordance with the pulse repetition frequency. Accordingly, even if the lightning is irradiated from the direction perpendicular to the substrate The light beam can also obtain an additional effect of suppressing interference caused by light reflection on the back of the substrate. The reason why interference can be suppressed is that by using a pulse width of the psec series, the time for the light returning to the semiconductor film to return to the semiconductor film from a glass substrate with a thickness of about 1 mm can be significantly shortened. On the other hand, the pulse width of a pulse oscillation laser using a normal pulse repetition frequency is in the range of 10 nsec to several hundreds of nsec, and the traveling distance of the light during this period is about 3 m to 100 m. However, the pulse width of the present invention uses a frequency of psec series. For example, during a pulse width of 10 psec, the travel distance of light is about 3 mm, which is much shorter than a conventional pulsed laser beam. Therefore, the time for the light that reciprocates back and forth to the glass substrate of about 1 mm and returns to the semiconductor film and the light newly incident on the semiconductor film becomes shorter, which makes it easy to suppress the occurrence of light interference. Therefore, there is no need to irradiate the laser beam from a direction oblique to the semiconductor film due to the influence of interference, and the laser beam can be irradiated from a direction perpendicular to the substrate. Therefore, the optical design is simple, and the uniformity of the energy distribution of the obtained beam spot can be further improved. In addition, when the laser beam is irradiated from an oblique direction, since the irradiation condition of the laser beam changes according to the scanning direction of the object to be processed, it is difficult to perform uniform laser annealing. In this case, in order to perform uniform laser annealing, it is necessary to perform laser annealing that scans only in one direction, so productivity has to be sacrificed. However, because the present invention can irradiate the laser from the vertical direction, the irradiation condition of the laser beam does not change depending on the scanning direction. Therefore, even if the workpiece is scanned back and forth, the uniformity of laser annealing will not be impaired, and productivity can be improved.

In addition, in order to avoid light interference at all, if the speed of light in vacuum is set to c, the refractive index of the substrate is set to n, and the thickness of the substrate is set to d, the pulse width t of the laser beam only needs to satisfy the following formula 1 The inequality shown is fine.

Formula 1 ct<2nd

For example, when a 0.7mm-thick glass substrate with a refractive index of 1.5 is used as the substrate and the speed of light in vacuum is 300,000 km/sec, the laser must not cause light interference at all, as long as the inequality t<7psec is satisfied.

In addition, when the polycrystalline semiconductor film is formed by the laser annealing method, if the energy of the laser beam fluctuates greatly, the uniform crystallization cannot be performed, so that the characteristics of the inter-TFT with the polycrystalline semiconductor film as the starting layer, such as The conduction current, mobility, etc. are not uniform. Note that even in a state where there is no interference, the laser beam has an energy swing of ±1% in time, so it can be considered that when the TFT used in the pixel portion of a semiconductor display device is formed, the energy is spatially swinging By suppressing it to a range of less than ±1%, it is possible to prevent the unevenness of brightness due to interference from being seen in the pixel portion.

On the other hand, when an amorphous semiconductor film formed on a glass substrate is irradiated with a second harmonic laser beam, about half of the laser beam is reflected on the surface of the amorphous semiconductor film, and the remaining half enters Inside the amorphous semiconductor film. The semiconductor film used for the startup layer of the TFT included in the semiconductor display device has a thickness of about several tens of nanometers. If the absorption coefficient of the amorphous semiconductor film is considered, it can be considered that the laser beam enters the amorphous semiconductor film. About half of it is absorbed by the amorphous semiconductor film, and the remaining half enters the glass substrate. Moreover, about 4% of the light entering the glass substrate is reflected on the inner surface of the substrate and re-enters the amorphous semiconductor film. Therefore, the proportion of light reflected on the inner surface of the glass substrate and incident on the amorphous semiconductor film relative to the light incident on the amorphous semiconductor film from the laser oscillator is about 2%. If the two laser beams When interference occurs, an energy swing of ±2% occurs.

Therefore, in order to suppress the spatial pendulum of the energy swing to less than ±1%, the interference time must be shortened to less than half of the pulse width t. It is desirable that the time for the two laser beams to irradiate any area of the amorphous semiconductor film at the same time is not more than 10% or less of the pulse width of the laser beam. When the interference time is shortened to less than half of the pulse width t, according to formula 1, it can be known that the pulse width t of the laser beam satisfies the inequality expressed by the following formula 2.

Formula 2 ct<4nd

The specific features of the laser irradiation device of the present invention are: a laser irradiation device including a pulsed laser oscillator; a nonlinear optical element for changing the wavelength of the laser emitted from the pulsed laser oscillator; and An optical system in which a laser whose wavelength has been changed is focused on the object to be processed, wherein the pulse repetition frequency of the pulsed laser oscillator is 10 MHz or higher. The laser irradiation device of the present invention having the above-mentioned structure can suppress the deterioration of the non-linear optical element compared with the case of using a continuously oscillating laser, and can increase the energy of the laser beam whose wavelength is changed, and expand the formation of the laser beam. The area of the beam spot on the processed object. In addition, the use of the laser irradiation device of the present invention to irradiate a semiconductor film is different from a conventional pulsed laser, and it is possible to form a semiconductor film having crystal grains that continuously grow in the scanning direction.

In addition, the specific feature of the laser irradiation method of the present invention is that a laser irradiation method includes the following steps: using a non-linear optical element to change the wavelength of the laser emitted from the pulse laser oscillator; The laser irradiates the object to be processed, and the pulse repetition frequency is 10MHz or higher. The laser irradiation method of the present invention having the above-mentioned structure can suppress the deterioration of the nonlinear optical element compared with the case of using a continuously oscillating laser, and, since the peak power is increased, the photon density with respect to time is increased, and the The conversion efficiency of non-linear optical elements to harmonics. Therefore, the energy of the laser beam whose wavelength has been changed can be increased, and the area of the beam spot formed on the object to be processed can be enlarged. As a result, productivity can be improved. In addition, the use of the laser irradiation device of the present invention to irradiate a semiconductor film is different from a conventional laser using pulsed oscillation, and it is possible to form a semiconductor film having crystal grains that continuously grow in the scanning direction.

In addition, the specific feature of the method of manufacturing a semiconductor device of the present invention is that: a method of manufacturing a semiconductor device includes the following steps: changing the wavelength of the laser emitted from the pulse laser oscillator with a non-linear optical element; The laser is irradiated to the object to be processed, and the pulse repetition frequency is 10MHz or higher. The manufacturing method of the semiconductor device of the present invention having the above-mentioned structure can suppress the deterioration of the nonlinear optical element compared with the case of using a continuously oscillating laser, and, since the peak power is increased, the photon density with respect to time is increased, and Improve the conversion efficiency of non-linear optical elements to harmonics. Therefore, the energy of the laser beam whose wavelength has been changed can be increased, and the area of the beam spot formed on the object can be enlarged. As a result, productivity can be improved and restrictions on the layout of semiconductor elements can be alleviated. In addition, the use of the manufacturing method of the present invention to form a semiconductor element is different from a conventional pulsed laser. It is possible to form a semiconductor element having a semiconductor film with crystal grains that continuously grow in the scanning direction, and improve the semiconductor element's performance. characteristic.

In addition, by making the beam spot linear, it is possible to further reduce the ratio of the areas of poor crystallinity formed on both ends of the long axis of the beam spot to the total beam spot area. However, the shape of the beam spot in the present invention is not limited to a linear shape. Even if it is a rectangular or planar shape, it is acceptable as long as it can sufficiently anneal the irradiated body.

Note that the oscillator that can be used in the present invention is a laser capable of performing pulse oscillation at a frequency of 10 MHz or higher. As long as it can perform oscillation at the above frequency, you can use Ar laser, Kr laser, excimer laser, CO₂Laser, YAG laser, Y₂O₃Laser, YVO₄Laser, YLF laser, YAlO₃Laser, GdVO₄Laser, ceramic laser, glass laser, ruby laser, emerald laser, Ti: sapphire laser, copper vapor laser or gold vapor laser.

In addition, in the semiconductor film crystallization process using a laser, the beam spot is processed into an elliptical or rectangular shape in one direction, and when the beam spot is scanned in the short axis direction and the semiconductor film is crystallized, it can improve productivity. The shape of the processed laser beam becomes elliptical because the original laser shape is circular or approximately circular. If the original shape of the laser is rectangular, it can also be processed by magnifying it in one direction with a cylindrical lens or the like to make the long axis longer. In addition, it is also possible to process a plurality of laser beams into a long ellipse or a rectangle in one direction, and connect them to make a longer beam in one direction to further improve the productivity.

The method of manufacturing a semiconductor device of the present invention can be used in a method of manufacturing an integrated circuit or a semiconductor display device. The semiconductor display device includes, for example, a liquid crystal display device, a light-emitting device having a light-emitting element represented by an organic light-emitting element in each pixel, DMD (digital micromirror device), PDP (plasma display panel), and FED (field emission display) )Wait.

In the present invention, compared with a continuously oscillating laser, the area of the beam spot can be greatly enlarged. Therefore, the proportion of regions with poor crystallinity in the beam spot can be reduced, and productivity can be improved. In addition, the present invention can suppress thermal damage to the glass substrate compared with a continuously oscillating laser. In addition, according to the present invention, the durability of the nonlinear optical element can be improved compared with a continuously oscillating laser, so that the complicated process of maintaining the nonlinear optical element can be reduced. Especially in the case of using solid lasers, the advantages of solid lasers that can be maintained without maintenance can be effectively used. In addition, the present invention is different from the case of a conventional pulsed laser in that the crystal plane can be continuously grown in the scanning direction, and a group of crystal grains composed of single crystals elongated in the scanning direction can be formed.

Hereinafter, the structure of the laser irradiation device of the present invention will be described using FIG. 1.

In Figure 1, 101 is a pulsed laser oscillator. In this embodiment mode, 1.8W YVO is used₄Laser. 102 corresponds to a non-linear optical element. The laser oscillator 101 is a stable resonator, and it is best to use TEM₀₀The oscillation mode. TEM₀₀Since the laser has a Gaussian-shaped intensity distribution, it has excellent condensing properties and can make the processing of the beam spot easier. The laser beam oscillated from the laser oscillator 101 is converted into the second harmonic (532 nm) by the nonlinear optical element 102. Although it is not necessary to be limited to the second harmonic, in terms of energy efficiency, the second harmonic is still superior to the higher harmonics. Set the pulse repetition frequency to 80MHz, and the pulse width to be about 12psec. In this embodiment mode, although a solid laser with an output of about 1.8W is used, a large laser with an output of 300W can also be used. In addition, it is also possible to use the third harmonic with a pulse repetition frequency of 80 MHz for laser scribe or the like.

Note that the pulse repetition frequency of the present invention is not limited to 80 MHz, as long as it is 10 MHz or higher. In addition, in the present invention, in a range that does not hinder the light-gathering property, while maintaining the uniform wavefront and obtaining a laser beam with high roundness, the maximum limit of the pulse pulse repetition frequency may be set to 100 GHz.

In addition, the nonlinear optical element 102 of the laser irradiation device of the present invention may be provided in the resonator of the laser oscillator 101, or a resonator provided with other nonlinear optical elements may be provided in addition to the fundamental wave oscillator. The former has the advantages of miniaturization of the device and no need to precisely control the length of the resonator, and the latter has the advantage of being able to ignore the interaction between the fundamental wave and the harmonics.

In the nonlinear optical element 102, KTP (KTiOPO₄), BBO (β-BaB₂O₄), LBO (LiB₃O₅), CLBO(CsLiB₆O₁₀), GdYCOB(YCa₄O(BO₃)₃), KDP (KD₂PO₄), KB5, LiNbO₃, Ba₂NaNb₅O₁₅In particular, by using LBO or BBO, KDP, KTP, KB5, CLBO, etc., the conversion efficiency from fundamental to harmonic can be improved.

From the point of view that the laser is usually emitted in the horizontal direction, the laser oscillated from the laser oscillator 101 passes through the mirror 103 and is transformed into a direction at an angle θ (incidence angle) to the vertical direction. Forward direction. In this embodiment mode, θ=18°. The laser whose advancing direction is changed is processed into the shape of its beam spot by the lens 104, and is irradiated on the object to be processed placed on the stage 107. In FIG. 1, the semiconductor film 106 formed on the substrate 105 corresponds to the object to be processed. In FIG. 1, the mirror 103 and the lens 104 correspond to an optical system that condenses the laser beam on the semiconductor film 106.

FIG. 1 shows an example of using a plano-convex spherical lens as the lens 104. The focal distance of the plano-convex spherical lens is 20mm. In order to make the laser beam enter the center of the curved surface of the lens 104, the plane of the lens 104 is set in parallel with the substrate 105. In addition, the distance between the plane of the plano-convex spherical lens and the semiconductor film 106 is 20 mm. Thus, a beam spot 110 having a size of about 10 μm×100 μm is formed on the semiconductor film 106. The fact that the beam spot 110 can be elongated is due to the astigmatism of the lens 104.

As shown in FIG. 1, in the case of using a substrate 105 on which a semiconductor film 106 is formed as an object to be processed, if the semiconductor film 106 is an amorphous semiconductor, it is preferable to perform a thermal annealing treatment on the semiconductor film 106 before irradiating the laser to The resistance of the semiconductor film 106 to lasers is improved. The specific thermal annealing treatment is, for example, a thermal annealing treatment at 500°C for 1 hour in a nitrogen atmosphere. In addition to the thermal annealing treatment, crystallization by thermal annealing treatment using a metal catalyst can also be performed. Regardless of the semiconductor film that has been thermally annealed, or the semiconductor film that is crystallized using a metal catalyst, the most suitable laser irradiation conditions are almost the same.

The stage 107 has an automaton for scanning in the X-axis direction (single-axis automata for X-axis) 108 and an automata for scanning in the Y-axis direction (single-axis automata for Y-axis) 109 It is possible to move in the XY direction in a plane parallel to the substrate 105.

Furthermore, a single-axis robot 109 for the Y axis is also used to scan the stage 107 in the short axis direction of the beam spot 110. At this time, the scanning speed of the stage 107 is preferably from several tens of mm/sec to several thousand mm/sec (more preferably from 100 to 2000 mm/sec), and here is 400 mm/sec. By scanning the stage 107, the beam spot 110 relatively scans the surface of the semiconductor film 106. As a result, the semiconductor film in the area irradiated by the beam spot 110 is melted, and the solid-liquid interface moves continuously in the scanning direction. In the area with a width of 70 μm, the crystal grows in the scanning direction in a paved state. It is a single crystal grain with a width of a few μm and a length of about 10-30 μm.

Next, the scanning path of the beam spot 110 on the surface of the semiconductor film 106 will be described with reference to FIG. 2. When the laser beam is irradiated on the entire surface of the semiconductor film 106 as the object to be processed, the Y-axis single-axis robot 109 is used to scan in one direction, and the X-axis single-axis robot 108 is used to perform scanning in one direction. The beam spot 110 slides in the scanning direction perpendicular to the single-axis automaton 109 for the Y-axis.

For example, the beam spot 110 is scanned in one direction by a single-axis robot 109 for the Y axis. In Figure 2, the scan path is represented by A1. Next, the single-axis robot 108 for the X axis is used to slide the beam spot 110 in a direction perpendicular to the scanning path A1. Let B1 denote the scanning path according to the sliding. Next, facing the direction opposite to the scanning path A1, the beam spot 110 is scanned in one direction by the single-axis robot 109 for the Y axis. The scan path is represented by A2. Next, the single-axis robot 108 for the X axis is used to slide the beam spot 110 in a direction perpendicular to the scanning path A2. The scanning path based on this sliding is denoted by B2. In this way, by sequentially repeating scanning through the single-axis robot 109 for the Y axis and scanning through the single-axis robot 108 for the X axis, the entire surface of the semiconductor film 106 can be irradiated with the laser beam.

The region where the crystal grains grown in the scanning direction are irradiated with the laser beam has very good crystallinity. Therefore, by using this region as the channel formation region of the TFT, extremely high mobility and on-current can be obtained. However, in the semiconductor film, when there is a part that does not need to be such a high crystallinity, the laser may not be irradiated to the part. Alternatively, the laser can be irradiated by increasing the scanning speed and other conditions where high crystallinity cannot be obtained.

In addition, the laser scanning can use the irradiation system movement type that fixes the substrate as the object to be processed and moves the irradiation position of the laser; as shown in Figure 1 and Figure 2, the irradiation position of the laser is fixed and the object to be processed on the substrate is moved. The type of movement; and the method that combines the above two methods. In either case, it is assumed that the relative movement direction of each beam spot with respect to the semiconductor film can be controlled.

Fig. 3 shows a 500-fold magnified photograph of the semiconductor film after being irradiated with a laser beam with an optical microscope. In Figure 3, silicon oxide with a thickness of 200 nm is formed on a single surface of a glass substrate with a thickness of 0.7 mm, and an amorphous silicon (a-Si) film with a thickness of 66 nm is formed as a semiconductor film by a plasma CVD method. The amorphous silicon film is thermally annealed at 500°C for 1 hour in a nitrogen atmosphere to improve the laser resistance of the semiconductor film. Next, using the laser irradiation device shown in Figure 1, the 1.8W YVO₄The second harmonic of the laser (532nm), TEM₀₀Mode, pulse repetition frequency of 80MHz, pulse width of 12psec, and scanning speed of 400mm/sec, irradiate a laser with a beam spot of about 10μm×100μm to perform crystallization.

By using the laser irradiation method of the present invention, as shown in FIG. 3, in the area indicated by A-A' with a width of 70 μm, the width of a few μm in which the crystal grows in the scanning direction is formed in a paved state, Single crystal grains with a length of about 10-30μm.

In addition, as a comparative example, the 18W YVO₄The second harmonic of the laser (532nm), TEM₀₀Mode, pulse repetition frequency of 100kHz, pulse width of 40nsec, and scanning speed of 200mm/sec, irradiate a laser beam spot with a size of about 7μm×6mm to perform crystallization. In this case, the crystal grains formed by the laser beam of one pulse and the crystal grains formed by the laser beam of the next pulse are not connected at the crystalline level, so that the A-A' shown in Fig. 3 cannot be obtained. The crystalline state formed in.

Example 1

In this embodiment, the optical system included in the laser irradiation device of the present invention will be described using FIGS. 4A and 4B.

The optical system shown in FIG. 4A has two cylindrical lenses 701 and 702. The beam spot of the laser beam incident from the arrow direction is shaped by two cylindrical lenses 701 and 702, and then irradiated onto the object 703 to be processed. Note that the focal length of the cylindrical lens 702 located closer to the processed object 703 is shorter than the focal length of the cylindrical lens 701.

In addition, in the present invention, when a laser beam with a pulse width of about 10 psec is used, the optical system can be installed without considering the influence of interference. In other words, the laser beam can be irradiated from a direction perpendicular to the object 703 to be processed.

Fig. 4B shows the optical system when four beam spots are combined to form one beam spot. The optical system shown in FIG. 4B includes six cylindrical lenses 717-722. The four laser beams respectively incident from the direction of the arrows are incident into the four cylindrical lenses 719-722. The beam spots of the two laser beams formed by the cylindrical lenses 719 and 721 are reshaped by the cylindrical lens 717 and then irradiated to the object 723 to be processed. On the other hand, the beam spots of the other two laser beams formed by the cylindrical lenses 720 and 722 are reshaped by the cylindrical lens 718 and then irradiated to the object 723 to be processed.

The beam spots of each laser beam on the processed object 723 are combined to form a beam spot that partially overlaps each other.

Although the focal length and incident angle of each lens can be appropriately determined by the designer, the focal lengths of the cylindrical lenses 717 and 718 located closest to the object to be processed 723 should be made shorter than the focal lengths of the cylindrical lenses 719-722. For example, if the focal lengths of the cylindrical lenses 717 and 718 located closest to the object to be processed 723 are set to 20 mm, the focal lengths of the cylindrical lenses 719-722 are set to 150 mm. In this embodiment, the incident angle of the laser beam from the cylindrical lenses 717 and 718 to the processed object 723 is set to 25 degrees, and the laser beams from the cylindrical lenses 719-722 to the cylindrical lenses 717 and 718 are set to 25 degrees. Each lens is set when the incident angle of the incident light beam is 10 degrees.

Fig. 4B shows an example of combining four beam spots. In this case, the optical system has four cylindrical lenses corresponding to the four laser oscillators and two cylindrical lenses corresponding to the four cylindrical lenses. The number of combined beam spots is not limited to this, and the number can be at least 2 to at most 8. When n (n=2, 4, 6, 8) beam spots are combined, the optical system has n cylindrical lenses corresponding to n laser oscillators and n/2 corresponding to the n cylindrical lenses. Cylindrical lens. When combining n (n=3, 5, 7) beam spots, the optical system has n cylindrical lenses corresponding to n laser oscillators and (n+1)/2 corresponding to n cylindrical lenses. A cylindrical lens.

When five or more beam spots overlap, it is desirable to emit the fifth and subsequent laser beams from the back side of the substrate in consideration of the position where the optical system is set, interference, etc. Moreover, the substrate needs to be translucent.

In addition, the optical system in the laser irradiation device of the present invention is not limited to the structure described in this embodiment.

Example 2

Hereinafter, the laser irradiation method and the manufacturing method of the semiconductor device of the present invention will be described using FIGS. 5A-5C.

First, as shown in FIG. 5A, a base film 501 is formed on a substrate 500. As the substrate 500, for example, a glass substrate such as barium borate glass or boro-aluminum oxide glass, a quartz substrate, a stainless steel substrate, or the like can be used. In addition, substrates made of plastics such as PET, PES, PEN, or flexible synthetic resins such as acrylic, generally tend to have lower heat-resistant temperatures than the above-mentioned substrates, but as long as they can withstand the processing temperature in the manufacturing process , Can be used.

The base film 501 is provided to prevent alkali metals such as Na contained in the substrate 500 or earth-based metals from diffusing in the semiconductor film and adversely affecting the characteristics of the semiconductor element. Therefore, it is formed using an insulating film of silicon oxide, silicon nitride, silicon oxynitride, or the like that can suppress the diffusion of alkali metals or earth-based metals into the semiconductor film. In this embodiment, a plasma CVD method is used to form a silicon oxynitride film with a thickness of 10 nm to 400 nm (preferably 50 nm to 300 nm) as the base film.

In addition, the base film 501 may be a single layer or a stacked layer formed by laminating a plurality of insulating films. In addition, when using substrates containing alkali metals or earth-based metals such as glass substrates, stainless steel substrates, or plastic substrates, it is effective to provide a base film from the viewpoint of preventing the diffusion of impurities. However, when using quartz that does not have the problem of diffusion of impurities In the case of a substrate or the like, it is not necessary to provide a base film.

Next, a semiconductor film 502 is formed on the base film 501. The thickness of the semiconductor film 502 is 25 nm to 100 nm (preferably 30 nm to 60 nm). In addition, the semiconductor film 502 may be an amorphous semiconductor or a polycrystalline semiconductor. In addition, not only silicon is used for semiconductors, but also silicon-germanium alloys. In the case of using silicon germanium alloy, the concentration of germanium is preferably 0.01atomic%~4.5atomic%.

Next, as shown in FIG. 5B, the laser irradiation device of the present invention is used to irradiate the semiconductor film 502 with a laser for crystallization.

In this embodiment, 2W energy and TEM are used as a laser₀₀Oscillation mode, second harmonic (532nm), pulse repetition frequency 80MHz, pulse width 12psec YVO₄Laser. In addition, by processing the laser with an optical system, the beam spot formed on the surface of the semiconductor film 502 has a minor axis of 10<i>μ</i>m, long axis is 100<i>μ</i>m rectangle. Note that the present invention is not limited to the irradiation conditions shown in this embodiment.

Furthermore, on the surface of the semiconductor film 502, the beam spot is scanned in the arrow direction as shown in FIG. 5B. By setting the pulse repetition frequency to 80MHz, the solid-liquid interface can be moved continuously in the direction of the arrow, so that growing crystal grains are continuously formed facing the scanning direction. By forming elongated single crystal grains in the scanning direction, it is possible to form a semiconductor film with almost no crystal grain boundaries at least in the TFT channel direction.

By irradiating the semiconductor film 502 with the above-mentioned laser, a semiconductor film 503 with higher crystallinity is formed.

Next, the semiconductor film 503 is patterned as shown in FIG. 5C to form island-shaped semiconductor films 507 to 509, and the island-shaped semiconductor films 507 to 509 are used to form various semiconductor elements typified by TFTs.

Although not shown, in the case of manufacturing a TFT, for example, a gate insulating film covering the island-shaped semiconductor films 507 to 509 is formed next. As the gate insulating film, for example, silicon oxide, silicon nitride, silicon oxynitride, or the like can be used. In addition, a plasma CVD method, a sputtering method, etc. can be used as a film forming method.

Next, a gate electrode is formed by forming and patterning a conductive film on the gate insulating film. Furthermore, using the gate electrode or the formed and patterned resist film as a mask, impurities imparting n-type or p-type conductivity are added to the island-shaped semiconductor films 507 to 509 to form source regions and drain regions, thereby forming LDD regions Wait.

The TFT can be formed through the series of steps described above. In addition, the manufacturing method of the semiconductor device of the present invention is not limited to the above-mentioned TFT manufacturing process after the formation of the island-shaped semiconductor film. By using the semiconductor film crystallized according to the laser irradiation method of the present invention as the TFT active layer, it is possible to suppress the unevenness of mobility, threshold, and on-current between elements.

In addition, it is also possible to provide a crystallization step using a catalyst element before performing the crystallization step by laser. As the catalyst element, nickel (Ni), germanium (Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pb), cobalt (Co), platinum (Pt), copper (Cu) can be used ), gold (Au) and other elements. If the laser-based crystallization step is performed after the crystallization step using a catalyst element is performed, the surface layer of the semiconductor film is melted by the laser irradiation, but the lower layer portion of the semiconductor film is not melted, so there remains The crystallization becomes a nucleus, and the crystallization proceeds uniformly from the lower layer to the upper layer. Compared with the case where the crystallization process is performed only by the laser, the crystallinity of the semiconductor film can be improved and the use of laser crystallization can be suppressed. The surface of the semiconductor film after the roughness. Therefore, it is possible to further suppress the dispersion of the characteristics of the semiconductor element to be formed later, such as a representative TFT, and to suppress the on-current.

In addition, after adding a catalyst element, a heat treatment may be performed to promote crystallization, and then the crystallinity may be further improved by laser irradiation, or the heat treatment step may be omitted. Specifically, it is also possible to irradiate a laser after adding a catalyst element instead of heat treatment to improve crystallinity.

In this embodiment, although an example of using the laser irradiation method of the present invention in the crystallization of a semiconductor film is shown, the laser irradiation method of the present invention can also be used for the activity of impurity elements doped to the semiconductor film. change.

Example 3

This embodiment is different from Embodiment 2 in that the description is given for an example in which the crystallization method by the catalyst element is combined with the crystallization method of the laser irradiation device according to the present invention.

First, the steps up to the formation of the semiconductor film 502 are performed with reference to FIG. 5A of the second embodiment. Next, as shown in FIG. 6A, the surface of the semiconductor film 502 is spin-coated with a nickel acetate solution containing Ni in a weight conversion of 1 to 100 ppm. In addition, the addition of the catalyst is not limited to the above-mentioned method, and it may be added using a sputtering method, vapor deposition method, plasma treatment, or the like. In addition, the heat treatment is performed at 500 to 650°C for 4 to 24 hours, for example, at 570°C for 14 hours. By this heat treatment, the semiconductor film 520 with accelerated crystallization is formed in the longitudinal direction from the surface coated with the nickel acetate salt solution facing the substrate 500 (FIG. 6A ).

As the heating treatment, for example, RTA (rapid heating annealing treatment) using lamp radiation as a heat source, or RTA (gas RTA) using heated gas to perform RTA at a set heating temperature of 740° C. for 180 seconds. The set heating temperature is the temperature of the substrate measured with a pyrometer, and this temperature is used as the set temperature during the heat treatment. As another method, a heat treatment at 550°C for 4 hours using an annealing furnace in a furnace is also possible. The lowering of the crystallization temperature and the shortening of the time shrinkage are achieved by the action of the metal element that has the function of a catalyst.

In addition, although nickel (Ni) is used as the catalyst element in this embodiment, in addition to this, germanium (Ge), iron (Fe), palladium (Pd), tin (Sn), lead (Pb) ), cobalt (Co), platinum (Pt), copper (Cu), gold (Au) and other elements.

Then, as shown in FIG. 6B, the semiconductor film 520 is crystallized using the laser irradiation device of the present invention. In this embodiment, a pulsed YVO with a pulse repetition frequency of 80 MHz and a pulse width of about 12 psec is used as the laser beam.₄The second harmonic of the laser. In addition, by processing the laser with an optical system, the beam spot 527 formed on the surface of the semiconductor film 520 has a minor axis of 10<i>μ</i>m, long axis is 100<i>μ</i>m rectangle. Note that the present invention is not limited to the irradiation conditions shown in this embodiment.

Also, on the surface of the semiconductor film 520, the beam spot is scanned in the arrow direction as shown in FIG. 6B. By setting the pulse repetition frequency to 80MHz, the solid-liquid interface can be moved continuously in the direction of the arrow, so that growing crystal grains are continuously formed facing the scanning direction. By forming elongated single crystal grains in the scanning direction, it is possible to form a semiconductor film with almost no crystal grain boundaries at least in the TFT channel direction.

By performing the above-mentioned laser irradiation on the semiconductor film 520, the semiconductor film 521 whose crystallinity is further improved is formed. In addition, it can be considered that the semiconductor film 521 crystallized using a catalyst element contains approximately 1×10¹⁹atoms/cm³About the concentration of the catalyst element (here, nickel). Next, gettering of the catalyst element existing in the semiconductor film 521 is performed.

First, as shown in FIG. 6C, an oxide film 522 is formed on the surface of the semiconductor film 521. By forming the oxide film 522 with a thickness of 1 nm to 10 nm, it is possible to prevent the surface roughness of the semiconductor film 521 due to etching in the subsequent etching process. The oxide film 522 can be formed using a well-known method. For example, it can be formed by oxidizing the surface of the semiconductor film 521 with an aqueous solution of sulfuric acid, hydrochloric acid, nitric acid, etc. and a hydrogen peroxide solution or ozone water. It can also be formed by plasma treatment or heat treatment in an oxygen-containing atmosphere, or ultraviolet Irradiation and so on to form. In addition, the oxide film 522 may be separately formed by a plasma CVD method, a sputtering method, or an evaporation method.

Next, on the oxide film 522, a sputtering method is used to form a concentration of 1×10 with a thickness of 25~250nm.²⁰atoms/cm³The semiconductor film 523 for gettering of the above rare gas elements. As the semiconductor film 523 for gettering, it is preferable to use a semiconductor film having a lower film density than the semiconductor film 521 so as to have a larger etching selectivity ratio with respect to the semiconductor film 521. As the rare gas element, one or more selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) are used.

Next, use the furnace annealing method or the RTA method to heat treatment and perform gettering. When heat treatment is performed by the furnace annealing method, heat treatment is performed at 450 to 600°C for 0.5 to 12 hours in a nitrogen atmosphere. In addition, when the RTA method is used for heating treatment, the light source for heating is turned on for 1 to 60 seconds, preferably 30 to 60 seconds, and repeated 1 to 10 times, preferably 2 to 6 times. Although the luminous intensity of the light source is arbitrary, the luminous intensity should be set to instantaneously heat the semiconductor film to 600~1000°C, preferably 700~750°C.

By the heat treatment, the catalyst element in the semiconductor film 521 moves to the semiconductor film 523 for gettering as indicated by the arrow by diffusion, and is gettered.

Next, the semiconductor film 523 for gettering is selectively etched and removed. Etching can be done according to ClF₃Dry etching without plasma, or according to containing or tetramethyl ammonium hydroxide ((CH₃)₄NOH) is performed by wet etching with a solution such as an aqueous solution. At this time, because of the oxide film 522, the semiconductor film 521 can be prevented from being etched.

Next, after removing the oxide film 522 with hydrofluoric acid, the semiconductor film 521 is patterned to form island-shaped semiconductor films 524 to 526 (FIG. 6D). The island-shaped semiconductor films 524 to 526 can be used to form various semiconductor elements typified by TFTs. In addition, the gettering step in the present invention is not limited to the method shown in this embodiment. Other methods can also be used to reduce the catalyst element in the semiconductor film.

In this embodiment, the surface layer of the semiconductor film is melted by the laser irradiation, but the lower layer of the semiconductor film is not melted. Therefore, the remaining crystals in the lower layer become nuclei, and the crystallization is uniform from the lower layer to the upper layer. In addition, since it is easy to match the crystal orientation, compared with Example 2, surface roughness can be suppressed. Therefore, it is possible to further suppress the dispersion of the characteristics of the semiconductor element to be formed later, which is typically TFT.

In addition, in this embodiment, a description is given of a structure in which a heat treatment is performed after the addition of a catalyst element to promote crystallization, and then the crystallinity is further improved by laser irradiation. However, the present invention is not limited to this, and the heat treatment step may be omitted. Specifically, it is also possible to irradiate a laser instead of heat treatment after adding a catalyst element to improve crystallinity.

Example 4

In this embodiment, a description will be given of an example different from Embodiment 3 in which the crystallization method by a catalyst element is combined with the crystallization method of the laser irradiation device according to the present invention.

First, the steps up to the formation of the semiconductor film 502 are performed with reference to the drawing of FIG. 5A in the second embodiment. Next, a mask 540 having an opening portion is formed on the semiconductor film 502. Then, as shown in FIG. 7A, the surface of the semiconductor film 502 is spin-coated with a nickel acetate salt solution containing Ni in a weight conversion of 1 to 100 ppm. In addition, the addition of the catalyst is not limited to the above-mentioned method, and it may be added using a sputtering method, vapor deposition method, plasma treatment, or the like. The coated nickel acetate salt solution is in contact with the semiconductor film 502 at the opening of the mask 540 (FIG. 7A).

Next, heat treatment is performed at 500 to 650°C for 4 to 24 hours, for example, at 570°C for 14 hours. By this heat treatment, a semiconductor film 530 in which crystallization is promoted is formed from the surface coated with the nickel acetate salt solution as indicated by the solid arrow (FIG. 7A ). The method of heat treatment is not limited to this, and other methods shown in Example 3 can also be used. In addition, as the catalyst element, the elements listed in Example 3 can be used.

Next, after removing the mask 540, as shown in FIG. 7B, the semiconductor film 530 is crystallized using the laser irradiation device of the present invention. In this embodiment, YVO with energy of 2W, second harmonic (532nm), pulse repetition frequency of 80MHz, and pulse width of 12psec is used.₄Laser. In addition, by processing the laser beam with an optical system, the beam spot 538 formed on the surface of the semiconductor film 530 has a minor axis of 10<i>μ</i>m, long axis is 100<i>μ</i>m rectangle. Note that the present invention is not limited to the irradiation conditions shown in this embodiment.

Also, on the surface of the semiconductor film 530, the beam spot 538 is scanned in the arrow direction as shown in FIG. 7B. By setting the pulse repetition frequency to 80MHz, the solid-liquid interface can be continuously moved in the direction of the arrow, so that the growing crystal grains are continuously formed when facing the scanning direction. By forming elongated single crystal grains in the scanning direction, it is possible to form a semiconductor film with almost no crystal grain boundaries at least in the TFT channel direction.

By performing the above-mentioned laser irradiation on the semiconductor film 530, the semiconductor film 531 whose crystallinity is further improved is formed.

In addition, it can be considered that the semiconductor film 531 crystallized using a catalyst element as shown in FIG. 7B contains approximately 1×10¹⁹atoms/cm³About the concentration of the catalyst element (here, nickel). Next, gettering of the catalyst element existing in the semiconductor film 531 is performed. First, as shown in FIG. 7C, a 150-nm-thick silicon oxide film 532 for a mask is formed to cover the semiconductor film 531, and an opening is provided by patterning, thereby exposing a part of the semiconductor film 531. Furthermore, the addition of phosphorus provides a region 533 to which phosphorus is added in the semiconductor film 531. In this state, if heat treatment is performed at 550 to 800°C for 5 to 24 hours in a nitrogen atmosphere, for example, at 600°C for 12 hours, the phosphorus-added region 533 of the semiconductor film 531 functions as a gettering site. , The catalyst element remaining in the semiconductor film 531 is segregated to the gettering region 533 to which phosphorus is added.

Furthermore, by etching and removing the phosphorus-added region 533, the concentration of the catalyst element in the remaining region of the semiconductor film 531 is reduced to 1×10¹⁷atoms/cm³the following. Next, after removing the silicon oxide film 532 used as a mask, the semiconductor film 531 is patterned to form island-shaped semiconductor films 534 to 536 (FIG. 7D). Using the island-shaped semiconductor films 534 to 536, various semiconductor elements typified by TFTs can be formed. In addition, the gettering process of the present invention is not limited to the method shown in this embodiment. Other methods can also be used to reduce the catalyst element in the semiconductor film.

In this embodiment, the surface layer of the semiconductor film is melted by the laser irradiation, but the lower layer of the semiconductor film is not melted. Therefore, the remaining crystals in the lower layer become nuclei, and the crystallization is uniform from the lower layer to the upper layer. In addition, since it is easy to match the crystal orientation, compared with Example 2, surface roughness is suppressed. Therefore, the dispersion of the characteristics of the semiconductor elements formed later, typically TFTs, is further suppressed.

In addition, the present embodiment is described for a structure in which a heating treatment is performed after the addition of a catalyst element to promote crystallization, and then the crystallinity is further improved by laser irradiation. However, the present invention is not limited to this, and the heat treatment step may be omitted. Specifically, it is also possible to irradiate a laser instead of heat treatment after adding a catalyst element to improve crystallinity.

Example 5

This embodiment will use FIG. 8 to describe the structure of a pixel of a light-emitting device, which is one of the semiconductor display devices formed using the laser irradiation device of the present invention.

In FIG. 8, a base film 6001 is formed on a substrate 6000, and a transistor 6002 is formed on the base film 6001. The transistor 6002 has an island-shaped semiconductor film 6003, a gate electrode 6005, and a gate insulating film 6004 sandwiched between the island-shaped semiconductor film 6003 and the gate electrode 6005.

The island-shaped semiconductor film 6003 uses a polycrystalline semiconductor film crystallized by using the laser irradiation device of the present invention. In addition, not only silicon but also silicon-germanium alloy can be used for the island-shaped semiconductor film. When using silicon-germanium alloy, the concentration of germanium is preferably 0.01~4.5atomic%. In addition, silicon to which carbon nitride has been added can also be used.

In addition, silicon oxide, silicon nitride, or silicon oxynitride can be used for the gate insulating film 6004. In addition, they are laminated films, such as SiO₂A film on which SiN is laminated can also be used as the gate insulating film 6004. In addition, the gate electrode 6005 is formed of an element selected from Ta, W, Ti, Mo, Al, and Cu, or an alloy material or a compound material containing the above-mentioned elements as a main component. In addition, a semiconductor film typified by a polysilicon film doped with an impurity element such as phosphorus may also be used as the gate electrode 6005. In addition, instead of a single-layer conductive film, a multilayer conductive film may be laminated.

In addition, the transistor 6002 is covered by a first interlayer insulating film 6006, and a second interlayer insulating film 6007 and a third interlayer insulating film 6008 are sequentially stacked on the first interlayer insulating film 6006. The first interlayer insulating film 6006 can use a single layer or a stacked layer of silicon oxide, silicon nitride, or silicon oxynitride formed by a plasma CVD method or a sputtering method.

In addition, the second interlayer insulating film 6007 can use an insulating film containing Si-O bonding and Si-CHx bonding formed using an organic resin film, an inorganic insulating film, or a siloxane-based material as a starting material. In this example, non-photosensitive propylene was used. The third interlayer insulating film 6008 uses a film that is less likely to permeate substances that accelerate the deterioration of the light-emitting element, such as moisture and oxygen, than other insulating films. Representatively, for example, a DLC film, a carbon nitride film, a silicon nitride film formed by an RF sputtering method, or the like is used.

In addition, in FIG. 8, 6010 is a first electrode, 6011 is an electroluminescent layer, and 6012 is a second electrode. The portion where the first electrode 6010 overlaps the electroluminescent layer 6011 and the second electrode 6012 corresponds to the light-emitting element 6013. One of the transistors 6002 is a driving transistor that controls the current supplied to the light-emitting element 6013, and it and the light-emitting element 6013 are connected in series directly or via other circuit elements. The electroluminescent layer 6011 has a structure in which a single light-emitting layer or a plurality of layers including the light-emitting layer are laminated.

The first electrode 6010 is formed on the third interlayer insulating film 6008. In addition, an organic resin film 6014 used as a partition wall is formed on the third interlayer insulating film 6008. In addition, in this embodiment, although an organic resin film is used as a partition wall, it is also possible to use an inorganic insulating film and a siloxane-based material as a starting material including Si-O bonding and Si-CHx bonding. Insulating film of the same as the partition wall. The organic resin film 6014 has an opening portion 6015, and the light-emitting element 6013 is formed by overlapping the first electrode 6010, the electroluminescent layer 6011, and the second electrode 6012 in the opening portion.

Furthermore, a protective film 6016 is formed on the organic resin film 6014 and the second electrode 6012. The protective film 6016 and the third interlayer insulating film 6008 also use a film that is less likely to permeate substances that accelerate the aging of the light-emitting element such as moisture or oxygen than other insulating films, such as DLC film, carbon nitride film, and RF sputtering. Silicon nitride film formed by the method.

In addition, the organic resin film 6014 is preferably formed in a circular arc shape at the edge portion of the opening portion 6015 so that the electroluminescent layer 6011 formed on the organic resin film 6014 is overlapped without opening holes in the edge portion. Specifically, the radius of curvature of the curve drawn on the opening of the cross section of the organic resin film is preferably 0.2~2<i>μ</i>m. According to the above structure, the coverage of the electroluminescent layer or the second electrode formed later can be improved, and the first electrode 6010 and the second electrode 6012 can be prevented from being short-circuited in the small holes formed in the electroluminescent layer 6011. . In addition, by relaxing the stress of the electroluminescent layer 6011, it is possible to reduce a defect called shrinkage in which the light-emitting area is reduced, thereby improving reliability.

In addition, in FIG. 8, an example in which a positive photosensitive acrylic resin is used as the organic resin film 6014 is shown. The photosensitive organic resin includes a positive type in which the exposed area of energy rays such as light, electrons, and ions are removed, and a negative type in which the exposed area is left. In the present invention, a negative type organic resin film can be used. In addition, photosensitive polyimine may be used to form the organic resin film 6014. When the organic resin film 6014 is formed using negative acrylic, the edge portion of the opening portion 6015 has an S-shaped cross-sectional shape. At this time, the radius of curvature in the upper and lower edges of the opening is preferably 0.2~2<i>μ</i>m.

In addition, one of the first electrode 6010 and the second electrode 6012 is an anode, and the other is a cathode.

The anode can use other semi-transparent oxide conductive materials such as indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), gallium-added zinc oxide (GZO) and other conductive materials. The anode may also use indium tin oxide (hereinafter referred to as ITSO) containing ITO and silicon oxide, or a material in which 2%-20% of zinc oxide (ZnO) is mixed with indium oxide containing silicon oxide. In addition, in addition to the above-mentioned translucent oxide conductive material, a single-layer film composed of one or more materials selected from TiN, ZrN, Ti, W, Ni, Pt, Cr, Ag, Al, etc., can also be used. A stacked layer formed by combining titanium nitride and a film mainly composed of aluminum, or a stacked layer formed by combining a titanium nitride film, a film mainly composed of aluminum and a titanium nitride film, is used as an anode material. In addition, in the case of using a material other than the translucent oxide conductive material to obtain light from the anode side, the anode is formed with a thickness (preferably about 5 nm to 30 nm) capable of transmitting light.

As the cathode material, metals, alloys, compounds having conductivity, and mixtures of the foregoing materials, etc., can be used with a small work function. Specifically, alkali metals such as Li, Cs, etc. can be used; alkaline earth metals such as Mg, Ca, Sr, etc.; alloys containing these elements (Mg: Ag, Al: Li, Mg: In, etc.); and these compounds (CaF₂, CaN), in addition, rare earth metals such as Yb, Er, etc. can also be used. In addition, when an electron injection layer is provided in the electroluminescent layer 6011, other conductive layers such as Al may be used. When taking light from the cathode side, other semi-transparent oxide conductive materials such as indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), gallium-added zinc oxide (GZO), etc. can be used Comes as the material of the cathode. It is also possible to use indium tin oxide containing ITO and silicon oxide (hereinafter referred to as ITSO), or a material in which indium oxide containing silicon oxide is mixed with 2%-20% zinc oxide (ZnO). When a semi-transparent oxide conductive material is used as the cathode, it is preferable to provide an electron injection layer in the electroluminescent layer 6011 formed later. In addition, even if a translucent oxide conductive material is not used, by forming the thickness of the film of the cathode to allow light transmission (preferably 5 nm-30 nm), light can be taken from the cathode side. In this case, a translucent oxide conductive material may be used to form a translucent conductive layer connected above or below the cathode in order to suppress the surface resistance of the cathode.

Note that although FIG. 8 shows a structure in which the light emitted from the light-emitting element is irradiated to the side of the substrate 6000, the light-emitting element may have a structure in which the light is directed to the side opposite to the substrate.

Also, after actually completing the steps up to Figure 8, it is preferable to use a protective film (laminate film, ultraviolet curable resin film, etc.) or a translucent cover material with high sealing properties and less outgassing (sealing). So that the light-emitting element is not exposed to the outside air. In this case, if the inside of the covering material is filled with an inert gas atmosphere, or a water-absorbing material (for example, barium oxide) is arranged inside, the reliability of the light-emitting element can be improved.

Note that although the light-emitting device is cited as an example of the semiconductor display device in this embodiment, the semiconductor display device formed using the manufacturing method of the present invention is not limited to this.

<p>101Laser Oscillator</p><p>102Non-linear optical components</p><p>103Mirror</p><p>104Lens</p><p>105Substrate</p><p>106Semiconductor film</p><p>107 Stage</p><p>108Automata</p><p>109Automata</p><p>110Beam spot</p><p>500Substrate</p><p>501Basement membrane</p><p>502Semiconductor film</p><p>503Semiconductor film</p><p>507Island-shaped semiconductor film</p><p>508Island-shaped semiconductor film</p><p>509Island-shaped semiconductor film</p><p>510Beam spot</p><p>520Semiconductor film</p><p>521Semiconductor film</p><p>522Oxide film</p><p>523Semiconductor film</p><p>524Island-shaped semiconductor film</p><p>525Island-shaped semiconductor film</p><p>526Island-shaped semiconductor film</p><p>527Beam Spot</p><p>530Semiconductor film</p><p>531Semiconductor film</p><p>532Silica film</p><p>533area</p><p>534Island-shaped semiconductor film</p><p>535Island-shaped semiconductor film</p><p>536Island-shaped semiconductor film</p><p>538Beam Spot</p><p>540Mask</p><p>701Cylindrical lens</p><p>702Cylinder lens</p><p>703Object to be processed</p><p>717Cylinder lens</p><p>718Cylindrical lens</p><p>719Cylindrical lens</p><p>720Cylindrical lens</p><p>721Cylindrical lens</p><p>722Cylinder lens</p><p>723Processed object</p><p>6000Substrate</p><p>6001Basement membrane</p><p>6002Transistor</p><p>6003Island-shaped semiconductor film</p><p>6004Gate Insulation Film</p><p>6005Gate electrode</p><p>6006First interlayer insulating film</p><p>6007Second interlayer insulating film</p><p>6008The third interlayer insulating film</p><p>6010First electrode</p><p>6011Electroluminescence layer</p><p>6012Second electrode</p><p>6013Light-emitting element</p><p>6014Organic resin film</p><p>6015Opening part</p><p>6016Protective film</p>

In the drawings, FIG. 1 is a diagram showing the laser irradiation device of the present invention; FIG. 2 is a diagram showing the scanning path of the beam spot 110 on the surface of the semiconductor film 106; An enlarged photo of an optical microscope; FIGS. 4A and 4B show an example of the optical system of the laser irradiation device of the present invention; FIGS. 5A to 5C show the laser irradiation method of the present invention and the manufacturing method of a semiconductor device Figures 6A to 6D are diagrams showing the laser irradiation method and semiconductor device manufacturing method of the present invention; Figures 7A to 7D are diagrams showing the laser irradiation method and semiconductor device manufacturing method of the present invention; Figure 8 It is a diagram showing the pixel structure of a light-emitting device, which is one of semiconductor display devices formed using the laser irradiation device of the present invention.