Semiconductor device and manufacturing method thereof

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a semiconductor device such as an electronic component or an optical component, and a method for manufacturing the semiconductor device.

【0002】

[Conventional technology]

Conventionally, a conductive layer and an insulating layer are alternately laminated on a semiconductor substrate or an insulating substrate to form a multilayer wiring board, and electronic components such as LSI (large-scale integrated circuit) and VLSI (ultra-large-scale integrated circuit) are formed. I am making it. Further, an electric circuit is formed on a semiconductor substrate or an insulating substrate, and a light guide body is arranged, and the light guide body is processed to manufacture optical components such as an optical waveguide and an optical path conversion element.

【0003】

When manufacturing semiconductor devices such as the electronic components and optical components, laser ablation using laser light is often used. As the laser beam, for example, a laser beam in a high-intensity and high-energy ultraviolet region emitted from a KrF excimer laser apparatus is used. The laser beam is applied to a portion to be processed of the material to be processed, and the portion to be processed is instantaneously evaporated to process the material into a predetermined shape.

【0004】

Since the laser ablation is performed in a short time, there is an advantage that a portion other than the portion to be processed is hardly heated. Further, since the laser beam can be focused on a very small spot, there is an advantage that the material to be processed can be processed into a predetermined shape with high accuracy. Semiconductor devices manufactured by taking advantage of such laser ablation and methods for manufacturing the semiconductor devices include the following.

【0005】

FIG. 4A is a diagram showing a conventional semiconductor device. This semiconductor device has a PN junction diode 402 on the semiconductor substrate 401, and the diode 402 is electrically connected to the wiring 405 via the connection wiring 404. This semiconductor device is manufactured as follows.

【0006】

First, as shown in FIG. 4B, P-type impurities and N-type impurities are diffused on the semiconductor substrate 401 to form a PN junction diode 402, and then a lower insulating layer 406 made of polyimide is formed on the semiconductor substrate 401. Laminate.

【0007】

Subsequently, as shown in FIG. 4 (c), the lower insulating layer 406 above the diode 402 is irradiated with the laser beam 408, and the laser beam irradiated portion of the polyimide is evaporated by laser ablation to form the lower insulating layer 406. Form hole 410. The size of the hole 410 is 50 μm × 50 μm on a flat surface.

【0008】

Then, as shown in FIG. 4D, Al (aluminum) is vapor-deposited in the hole 410 and on the lower insulating layer 406 to form the connection wiring 404 and the wiring 405.

【0009】

Finally, the upper insulating layer 407 is laminated on the wiring 405 to obtain the semiconductor device shown in FIG. 4 (a).

【0010】

Since the hole 410 is formed in the lower insulating layer 406 having a relatively thick thickness made of polyimide by high-intensity and high-power laser light, it takes much shorter time than, for example, by RIE (reactive ion etching). Can form a hole 410. As a result, the manufacturing time of the semiconductor device is shortened.

【0011】

FIG. 5A is a diagram showing an optical component having a photodiode and an optical waveguide as a conventional semiconductor device. This semiconductor device includes a photodiode 502 formed on a semiconductor substrate 501, an ultraviolet absorbing layer 503 laminated on the semiconductor substrate 501 and the photodiode 502, a lower clad layer 504, and an optical waveguide 505. The optical waveguide 505 has a tapered portion at the right end in FIG. 5A, and the tapered portion guides the light of the optical waveguide 505 to the photodiode 502. The ultraviolet absorbing layer 503 has a function as an antireflection film of the clad layer 504 and a function of absorbing the laser beam 506 shown below.

【0012】

In the method of manufacturing this semiconductor device, first, as shown in FIG. 5 (b), a photodiode 502 is formed on a semiconductor substrate 501, and an ultraviolet absorbing layer 503 made of a silicon nitride film and a silicon oxide film are formed on the photodiode 502. The lower clad layer 504 and the optical waveguide 505 made of a polymer resin are further laminated.

【0013】

Then, around the end of the optical waveguide 505, the fluence was 0.5 J / cm by the KrF excimer laser device.²Irradiates a laser beam 506 with a wavelength of 248 nm. Then, the laser beam 506 is irradiated while moving in the longitudinal direction of the optical waveguide 505 as shown by an arrow A, and the end portion of the optical waveguide 505 is processed into a tapered shape (see JP-A-12-117465). .. In this way, the high-brightness, high-power KrF excimer laser instantaneously evaporates the workpiece 505 of the optical waveguide 505 made of polymer resin, and gives almost no heat to the periphery of the workpiece. 505 Process the end into a tapered shape. As a result, the tapered portion of the optical waveguide 505 can be made into a good light reflecting surface without causing distortion or scratches due to heat.

【0014】

The ultraviolet absorbing layer 503 absorbs the laser light 506 transmitted through the lower clad layer 504 when the optical waveguide 505 is processed so that the laser light 506 does not reach the semiconductor substrate 501 or the photodiode 502. I have to.

【0015】

FIG. 6A is a diagram showing a conventional semiconductor device, and shows a multilayer wiring board in which insulating layers 602,604 and wiring layers 603,606 are alternately formed on a substrate 601.

【0016】

In the manufacturing method of this semiconductor device, first, as shown in FIG. 6B, a lower insulating layer 602 made of polyimide, a lower wiring layer 603 made of Al, and an upper insulating layer made of polyimide are formed on a substrate 601. Form layer 604.

【0017】

Then, as shown in FIG. 6 (c), the upper insulating layer 604 is irradiated with excimer laser light 605, and holes 607 are formed in the upper insulating layer 604 by laser ablation.

【0018】

Then, Al is vapor-deposited inside the hole 607 and on the upper insulating layer 604 to form the connection wiring 609 connecting the upper wiring layer 606 and the lower wiring layer 603 and the upper wiring layer 606. The semiconductor device shown in 6 (a) can be obtained.

【0019】

The upper insulating layer 604 made of the above-mentioned polyimide has a thickness of several tens of μm or more, and when forming pores by RIE (reactive ion etching), it takes about half a day. On the other hand, according to the laser ablation, since the holes 607 can be formed in the upper insulating layer 604 substantially instantaneously, the manufacturing time of the semiconductor device can be significantly shortened.

【0020】

[Problems to be Solved by the Invention]

However, in the method of manufacturing the semiconductor device shown in FIG. 4, in the step of forming the hole 410 in the lower insulating layer 406 of FIG. 4 (c) by laser ablation, the diode 402 is directly irradiated to the laser beam 408 and the performance deteriorates. Or, there is a problem of damage. Specifically, the diode 402 has a size of 400 μm × 400 μm, and even if only a part of the diode 402 is irradiated with the laser beam 408, a leakage current of several tens of μA flows through the diode 402. , The function as a diode is lost.

【0021】

Further, in the method of manufacturing the semiconductor device shown in FIG. 5, when the end portion of the optical waveguide 505 of FIG. 5B is processed into a tapered shape by the laser beam 506, the laser beam 506 passes through the lower clad layer 504. It reaches the ultraviolet absorbing layer 503. However, since the laser beam 506 has high brightness and high output, it is not absorbed by the ultraviolet absorbing layer 503 and destroys the ultraviolet absorbing layer 503. The destruction of the ultraviolet absorbing layer 503 is remarkable around the end of the optical waveguide 505, which is the work piece. As a result, the semiconductor substrate 501 around the photodiode 502 below the end of the optical waveguide 505 is damaged by the laser beam 506, and the performance of the photodiode 502 deteriorates. If the laser beam 506 is stronger, the photodiode 502 will also be damaged. That is, the ultraviolet absorbing layer 503 made of the silicon nitride film, Furuen scan is 0.5 J / cm²The above-mentioned strong laser light does not have the effect of absorbing and blocking the laser light.

【0022】

Further, in the method for manufacturing the semiconductor device shown in FIG. 6, when the hole 607 is formed in the insulating layer 604 of FIG. 6 (c) by the laser light 605, the laser light 605 is the lower wiring layer below the insulating layer 604. Reach up to 603. Al, which is the material of the lower wiring layer 603, has a reflectance of about 80% with respect to the excimer laser light, so that about 20% of the laser light that is not reflected by the lower wiring layer 603 has thermal energy in the lower wiring layer 603. Is absorbed as. In this case, since the lower wiring layer 603 is formed on the lower insulating layer 602 made of polyimide having a relatively low thermal conductivity, the thermal energy is accumulated in the lower wiring layer 603, and the lower wiring layer 603 becomes It gets hot. As a result, there arises a problem that the lower wiring layer 603 is melted, peeled off, or blown off. Further, when the lower wiring layer 603 is melted, the laser beam reaches the lower insulating layer 602 below the lower wiring layer 603, and holes are formed in the lower insulating layer 602. As a result, there is a problem that foreign matter and residue are generated in the holes of the lower insulating layer 602 and cause migration.

【0023】

Therefore, an object of the present invention is to provide a semiconductor device in which a portion other than the portion to be processed is not adversely affected when processing is performed by laser light, and a method for manufacturing the semiconductor device.

【0024】

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the first invention includes a substrate having a semiconductor element, a processed layer provided on the substrate and the semiconductor element and processed by laser light, and the processed layer. It is characterized in that it is arranged between the semiconductor element or at least one of the substrates and has a damage prevention layer that reflects the laser beam.

【0025】

According to the above configuration, even if the laser beam for processing the work layer passes through the work layer and faces the substrate side, it is reflected by the damage prevention layer, so that the laser light is reflected by the semiconductor element or the semiconductor element or It is prevented from reaching the substrate. Therefore, deterioration or destruction of the performance of the semiconductor element due to the laser beam, or deterioration of the performance of the semiconductor element due to damage to the substrate is prevented.

【0026】

In one embodiment, the damage prevention layer has a reflectance of 80% or more with respect to the laser beam.

【0027】

According to the above embodiment, even if the laser beam for processing the work layer passes through the work layer and is directed to the substrate side, 80% or more of the laser light is directed to the work layer side by the damage prevention layer. Be reflected. Therefore, since the laser beam hardly reaches the substrate and the semiconductor element, damage to the substrate and deterioration or damage to the performance of the semiconductor element can be effectively prevented.

【0028】

Here, when the reflectance of the damage prevention layer with respect to the wavelength of the laser light is less than 80%, the damage prevention layer absorbs the laser light of the non-reflecting ratio of the laser light, and the absorbed laser. Stores the energy of light as heat energy. In this case, the amount of energy received as heat from the laser beam increases, and the risk of the damage prevention layer melting and evaporating due to this heat rapidly increases.

【0029】

The damage prevention layer may reflect 80% of the laser light by one layer, or may reflect 80% of the laser light by a plurality of layers of two or more layers.

【0030】

In one embodiment, the damage prevention layer is a metal film.

【0031】

According to the above embodiment, since the damage prevention layer is a metal film, the laser beam that has passed through the work layer and directed toward the substrate side is effectively reflected by the damage prevention layer, and thus the substrate. Damage and deterioration or destruction of the performance of the semiconductor element are effectively prevented.

【0032】

In one embodiment, the metal film is an Al film.

【0033】

According to the above embodiment, since the metal film is an Al film having a relatively large reflectance with respect to the laser light, most of the laser light passing through the work layer and directed toward the substrate side is the Al. Reflected by the membrane. Therefore, damage to the substrate and deterioration or destruction of the performance of the semiconductor element are surely prevented.

【0034】

In one embodiment, the Al film has a film thickness of 0.5 μm or more.

【0035】

According to the above embodiment, most of the laser light that has reached the Al film as the damage prevention layer is reflected by the Al film, while a part of the laser light is absorbed by the Al film without being reflected, and this absorption is achieved. The Al film is heated by the generated laser beam. However, since the Al film has a film thickness of 0.5 μm or more and the heat capacity of the Al film as a whole is relatively large, the Al film is not melted by the heat of the absorbed laser light. Therefore, the Al film can stably prevent the laser beam from reaching the substrate and the semiconductor element, and damage to the substrate and deterioration or destruction of the performance of the semiconductor element can be stably prevented.

【0036】

Here, when the film thickness of the Al film is 0.5 μm or less, the heat capacity of the Al film as a whole becomes small, and the risk of melting and evaporating the Al film due to the heat of the absorbed laser light increases.

【0037】

In one embodiment, the damage prevention layer is composed of two or more layers, and the layer on the work layer side of the damage prevention layers is a reflective layer that reflects the laser light, and is a damage prevention layer. The layer on the semiconductor element side is an absorption layer that absorbs the laser beam.

【0038】

According to the above embodiment, a part of the laser beam that has reached the damage prevention layer is first reflected by the damage prevention layer on the work layer side. Most of the laser light that reaches the damage prevention layer on the semiconductor element side without being reflected by the damage prevention layer on the work layer side is absorbed by the damage prevention layer on the semiconductor element side. In this way, the laser light that has reached the damage prevention layer is reflected and absorbed by the damage prevention layer, so that the laser light hardly reaches the substrate and the semiconductor element. Therefore, damage to the substrate and deterioration or destruction of the performance of the semiconductor element are surely prevented.

【0039】

If the layer to be processed reflects the laser light and the layer on the semiconductor element side absorbs the laser light, the damage prevention layer includes a layer that reflects the laser light and a layer that absorbs the laser light. And may be provided in any number of layers of one or more.

【0040】

In one embodiment, the reflective layer is a metal film and the absorbent layer is a silicon layer. Here, the silicon layer means a layer containing a Si element, and also includes a silicon oxide film and a silicon nitride film.

【0041】

According to the above embodiment, most of the laser light that has reached the damage prevention layer is reflected by the metal film, and further, the laser light that has passed through the metal film without being reflected by the metal film is large. The portion is absorbed by the silicon layer. Therefore, almost all the laser light that has reached the damage prevention layer does not reach the semiconductor element. As a result, damage to the substrate and deterioration or destruction of the performance of the semiconductor element are surely prevented.

【0042】

The semiconductor device of the second invention includes a substrate provided with metal wiring, a layer to be processed provided on the metal wiring and an opening formed in the metal wiring by laser light, and the substrate. It is characterized by having a heat conductive layer which is arranged between the metal wiring and has a higher thermal conductivity than the above substrate.

【0043】

According to the above configuration, when the layer to be processed is processed by laser light to form an opening to open in the metal wiring, the metal wiring is irradiated with the laser light and a part of the laser light becomes thermal energy. The metal wiring is heated. However, since a heat conductive layer having a higher thermal conductivity than that of the substrate is arranged between the metal wiring and the substrate provided with the metal wiring, the heat of the metal wiring is generated by the heat conductive layer. Is quickly released to the substrate. Therefore, the temperature of the metal wiring does not rise due to the accumulation of heat from the laser beam. As a result, problems such as melting and peeling of metal wiring are prevented.

【0044】

The opening is not limited to holes and grooves, but indicates a portion where one part of the work layer is removed to expose one part of the metal wiring, and the shape is not limited to the shape for removing the work layer. ..

【0045】

In one embodiment, the metal wiring is made of Al, and the heat conductive layer is a silicon oxide film, a silicon nitride film, or a Ni (nickel) film.

【0046】

According to the above embodiment, since the metal wiring is Al having a relatively high reflectance to the laser light, even if the laser light is irradiated to Al, the laser light absorbed by Al is relatively small. , The amount of heating of Al is small. Moreover, since the heat conductive layer is made of a silicon oxide film, a silicon nitride film, or a Ni film and has a relatively high thermal conductivity, the heat of Al is quickly dissipated to a portion other than Al. As a result, melting and peeling of the metal wiring made of Al are prevented.

【0047】

The method for manufacturing a semiconductor device according to the third invention includes a step of providing a damage prevention layer on a substrate having a semiconductor element, a step of providing a layer to be processed on the substrate and the damage prevention layer, and a step of providing a layer to be processed on the damage prevention layer. It is characterized by having a step of processing the work layer of the above by laser light.

【0048】

According to the method for manufacturing a semiconductor device of the third invention, when the layer to be processed is processed by the laser beam by providing the damage prevention layer on the substrate having the semiconductor element, the substrate or the semiconductor element The irradiation of the laser beam to is effectively prevented. As a result, the layer to be processed can be rapidly processed by the laser beam to manufacture the semiconductor device in a short time, and the substrate is not damaged, or the performance of the semiconductor element is not deteriorated or destroyed. A semiconductor device with performance can be manufactured.

【0049】

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1A is a diagram showing an electronic component which is a semiconductor device according to the first embodiment of the present invention.

【0050】

In this semiconductor device, a PN junction diode 2 as a semiconductor element is provided on the semiconductor substrate 1. In this semiconductor device, on the semiconductor substrate 1, a lower insulating layer 4 made of polyimide and as a layer to be processed by laser light, a wiring 6 made of Al formed on the lower insulating layer 4, and the wiring 6 are provided. It has an upper insulating layer 7 laminated on top and made of polyimide.

【0051】

Between the PN junction diode 2 and the lower insulating layer 4, a metal film pattern 3 as a damage prevention layer made of a Ni film is provided so as to cover the PN junction diode 2. The PN junction diode 2 is connected to the wiring 6 by a connection wiring 9 made of Al via the metal film pattern 3.

【0052】

This semiconductor device is manufactured as follows.

【0053】

First, as shown in FIG. 1 (b), a PN junction diode 2 is formed by diffusing p-type impurities and n-type impurities on the semiconductor substrate 1. Then, a metal film pattern 3 is formed on the semiconductor substrate 1 so as to cover the PN junction diode 2. In this metal film pattern 3, first, a Ni thin film is formed on the semiconductor substrate 1 and patterned to form a predetermined shape, and then Ni is further grown on the patterned Ni thin film by plating to a thickness of 10 μm. To do. Then, the lower insulating layer 4 made of polyimide is laminated on the semiconductor substrate 1 and the metal film pattern 3.

【0054】

Subsequently, as shown in FIG. 1 (c), the laser beam 11 is irradiated to the position corresponding to the diode 2 of the lower insulating layer 4, and the lower insulating layer 4 is subjected to the metal film pattern 3 by laser ablation. Form a hole 12 to reach.

【0055】

After that, as shown in FIG. 1 (d), Al is embedded in the hole 12 to form the connection wiring 9 and the Al layer is formed on the lower insulating layer 4 by the sputtering reflow method. Subsequently, the Al layer is patterned by RIE to form a wiring layer 6 having a predetermined wiring pattern.

【0056】

Finally, polyimide is applied and fired on the wiring layer 6 to form the upper insulating layer 7.

【0057】

In the above semiconductor device manufacturing method, the laser beam 11 used in the step shown in FIG. 1 (c) is oscillated by the KrF excimer laser device, and the fluence (pulse laser intensity per unit area) is 0.5 J / cm.²And the wavelength is 248 nm. The laser beam 11 can instantaneously evaporate the lower insulating layer 4 made of the polyimide to quickly form the holes 12 without forming a burning portion in the polyimide.

【0058】

Further, in the semiconductor device, a metal film pattern 3 made of Ni having a thickness of 10 μm is provided above the PN junction diode 2 of the semiconductor substrate 1. Therefore, the metal film pattern 3 causes the laser beam 11 to be PN. It is prevented from reaching the junction diode 2. Therefore, it is possible to prevent the PN junction diode 2 from being damaged by the laser beam 11.

【0059】

After manufacturing the semiconductor device, a reverse voltage of about 10 V was applied to the PN junction diode 2 and the leak current flowing at that time was measured. As a result, the leak current was on the order of several pA. Therefore, it can be said that the damage caused by the laser beam 11 of the diode 2 can be avoided.

【0060】

Further, since the metal film pattern 3 is made of a Ni film, the PN junction diode 2 and the connection wiring 9 can be electrically connected without any problem.

【0061】

The metal film pattern 3 may be formed by, for example, an Al film other than the Ni film. When the metal film pattern 3 is formed of an Al film, the thickness of the metal film pattern 3 can be reduced to 0.5 μm. As a result, the lower insulating layer 4 can be formed at a position above the boundary between the semiconductor substrate 1 and the metal pattern 3 without causing a step.

【0062】

FIG. 2A is a diagram showing an optical component as a semiconductor device according to the second embodiment of the present invention.

【0063】

This semiconductor device has a photodiode 202 as a semiconductor element on a semiconductor substrate 201, and a damage prevention layer composed of an ultraviolet absorbing layer 203 and an Al at the position of the photodiode 202 on the semiconductor substrate 201. The metal film 204, the lower clad layer 205, the optical waveguide 206, the upper clad layer 209 made of a silicon oxide film, and the stray light sealing film 210 made of Al. The ultraviolet absorbing layer 203 also has a function as an antireflection film of the lower clad layer 205.

【0064】

In this semiconductor device, the light of the optical waveguide 206 is reflected by the tapered portion formed at the right end of the optical waveguide 206 in FIG. 2A, and is received by the photodiode 202.

【0065】

This semiconductor device is manufactured as follows.

【0066】

First, as shown in FIG. 2 (b), the ultraviolet absorbing layer 203 and the Al film are laminated on the semiconductor substrate 201 provided with the photodiode 202, and the positions of the Al film corresponding to the photodiode 202 are located. It opens to form a metal film 204. Subsequently, the lower clad layer 205 and the optical waveguide 206 made of a polymer resin are laminated on the ultraviolet absorbing layer 203 and the metal film 204.

【0067】

Then, using a KrF excimer laser device, the fluence was 0.5 J / cm.²The end of the optical waveguide 206 is processed by a laser beam having a wavelength of 248 nm. That is, as shown in FIG. 2B, the laser beam 207 is applied to the optical waveguide 206 at right angles to the longitudinal direction of the optical waveguide 206, and is moved in the longitudinal direction of the optical waveguide 206 as shown by arrow B. Then, as shown in FIG. 2 (c), the end portion of the optical waveguide 206 is processed into a tapered shape.

【0068】

Subsequently, the upper clad layer 209 is laminated on the optical waveguide 206 and the lower clad layer 205, and finally, the stray light sealing film 210 is formed on the upper clad layer 209, as shown in FIG. 2 (a). The semiconductor device shown is completed.

【0069】

When the optical waveguide 206 shown in FIG. 2B is processed by the laser beam 207 in the manufacturing process of the semiconductor device, the metal film 204 prevents the semiconductor substrate 201 around the photodiode 202 from being damaged by the laser beam 207. Will be done. That is, even if the laser beam 207 passes through the lower clad layer 205 and faces the semiconductor substrate 201 side, most of the laser beam 207 is reflected by the metal film 204 made of the Al film. Further, since the amount of laser light that is not reflected by the metal film 204 and passes through the metal film 204 is very small, this small amount of laser light is effective for the ultraviolet absorbing layer 203 without damaging the ultraviolet absorbing layer 203. Be absorbed. Therefore, since the laser beam 207 hardly reaches the semiconductor substrate 201, the semiconductor substrate 201 around the photodiode 202 is not damaged. As a result, deterioration of the performance of the photodiode 202 can be prevented.

【0070】

After manufacturing the semiconductor device, the leakage current of the photodiode 202 was measured to confirm whether or not the photodiode 202 was affected by the laser beam. As a result, it was found that the leakage current of the photodiode 202 was on the order of several pA, and the photodiode 202 was not affected by the laser beam.

【0071】

Further, the metal film 204 made of the Al film may be used as a wiring of a semiconductor device, a light-shielding film of a photodiode, or a stray light sealing film of an optical waveguide, and in addition to a function as a damage prevention layer against laser light, It may be formed to have other functions.

【0072】

FIG. 3A is a diagram showing a multilayer wiring board which is an electronic component as a semiconductor device according to the third embodiment of the present invention. This semiconductor device has a lower insulating layer 302 made of a silicon oxide film, a lower wiring layer 303 made of Al, an upper insulating layer 304 made of polyimide, and an upper wiring layer 306 made of Al on a substrate 301. The lower wiring layer 303 and the upper wiring layer 306 are electrically connected by the connection wiring 308.

【0073】

This semiconductor device is manufactured as follows.

【0074】

First, as shown in FIG. 3 (b), a lower insulating layer 302 made of a silicon oxide film is formed on the substrate 301, and then a lower wiring layer 303 made of Al and an upper insulating layer 304 made of polyimide are formed. To do.

【0075】

Then, as shown in FIG. 3C, the upper insulating layer 304 is irradiated with excimer laser light 310 to form holes 312 in the upper insulating layer 304 that open in the lower wiring layer 303.

【0076】

Then, Al is embedded in the hole 312 to form the connection wiring 308, and Al is vapor-deposited on the upper insulating layer 304 to form the upper wiring layer 306, so that the semiconductor device shown in FIG. 6A is formed. Complete.

【0077】

When the hole 312 is formed in the upper insulating layer 304 by the laser ablation, the laser beam 310 irradiates the lower wiring layer 303 below the upper insulating layer 304. Al, which is the material of the lower wiring layer 303, has a reflectance of about 80% with respect to the excimer laser light 310. Therefore, about 20% of the laser light that the lower wiring layer 303 does not reflect is the lower part as thermal energy. Accumulated in the wiring layer 303, the lower wiring layer 303 is heated. However, since the lower insulating layer 302 to which the lower wiring layer 303 is in contact is made of a silicon oxide film having a higher thermal conductivity than the substrate 301, the heat of the lower wiring layer 303 is rapidly generated through the lower insulating layer 302. It is escaped to the substrate 301. Therefore, since the temperature of the lower wiring layer 303 hardly rises, the lower wiring layer 303 does not melt, peel off, or blow off as in the conventional case. As a result, as in the conventional case, the laser beam reaches the lower insulating layer 302 below the lower wiring layer 303, holes are formed in the lower insulating layer 302, and foreign matter generated in the holes of the lower insulating layer 302. Migration does not occur due to or residue. Therefore, according to the method for manufacturing a semiconductor device according to the present embodiment, a semiconductor device capable of forming holes 312 in the insulating layer 304 in a short time by laser light to manufacture the semiconductor device in a short time and having good performance can be obtained. can get.

【0078】

An experiment was conducted in which the damage prevention layer of the semiconductor device according to the present invention and the damage prevention layer of the comparative example were actually irradiated with laser light, and the action and effect of the damage prevention layer according to the present invention were compared with the comparative example.

【0079】

Table 1 is a table showing the states of the damage prevention layer of the present invention and the damage prevention layer of the comparative example after irradiation with laser light. The above laser beam is a laser beam generated by a KrF excimer laser device, and the wavelength of the laser beam is 248 nm and the fluence is 0.5 to 2.0 J / cm.²Is. The condition of the damage prevention layer is 0.5 to 2.0 J / cm.²Similar results were obtained by irradiating any of the fluence laser beams during the period. That is, in the state of the damage prevention layer, the fluence of the irradiated laser beam is 0.5 to 2.0 J / cm.²If it is between, it does not depend on the value of fluence.

【0080】

The damage prevention layer of Comparative Example 1 is SiO₂It is a film composed of two layers of Au (gold) and TiW (titanium / tungsten) formed on Si and Si, and has a layer thickness of 1.0 μm. The damage prevention layer of Comparative Example 1 is substantially the same as the damage prevention layer of Example 1 except for the type of metal film.

【0081】

The damage prevention layer of Comparative Example 2 is an Al film formed on polyimide, has a layer thickness of 1.1 to 2.0 μm, has a layer thickness thicker than that of Example 1, and has a layer thickness of Example. The lower layer is different from the damage prevention layer of 1.

【0082】

The damage prevention layers of Comparative Example 3 and Comparative Example 4 are both made of an Al film and are SiO.₂And Si, each of which differs from the damage prevention layer of Example 1 only in layer thickness.

【0083】

The Al films of Comparative Examples 2 to 4 and Example 1 were formed by thin-film deposition on the lower layer.

【0084】

[table 1]

<img file="JP2002164591A_D0001.tif" />【0085】

As can be seen from Table 1 above, the damage prevention layer composed of the two layers of Au and TiW of Comparative Example 1 is completely etched by the laser beam. This means that the Al film of Example 1 has a reflectance of about 80% with respect to laser light, whereas the two-layer film of Au and TiW of Comparative Example 1 has a reflectance of about 30 with respect to laser light. Due to being%. That is, about 70% of the laser light absorbed without being reflected by the damage prevention layer was accumulated as heat in the two layers of Au and TiW, and this heat melted and evaporated the damage prevention layer.

【0086】

Further, although the damage prevention layer of Comparative Example 2 has a relatively larger layer thickness than the damage prevention layer of Example 1, it is completely etched by the laser beam. This is because the damage prevention layer of Comparative Example 2 was formed on polyimide having a relatively low thermal conductivity. That is, the laser beam absorbed in the damage prevention layer of Comparative Example 2 is accumulated as heat, and the polyimide having a relatively low thermal conductivity prevents the heat from being dissipated to a portion other than the damage prevention layer. As a result of the rise in the temperature of the prevention layer, the damage prevention layer melted and evaporated.

【0087】

The damage prevention layer of Comparative Example 3 was completely etched by the laser beam. This is because the thickness of the Al film of Comparative Example 3 is smaller than that of the Al film of the damage prevention layer of Example 1.

【0088】

The damage prevention layer of Comparative Example 4 was not completely etched by the laser beam, but the gloss of the surface of the damage prevention layer changed, indicating that the Al film was slightly melted. This is because the layer thickness is 0.1 μm smaller than that of the damage prevention layer of Example 1 which is not melted by the laser beam.

【0089】

From the above experimental results, in order to surely exert the damage prevention effect on the laser beam without melting the damage prevention layer, the Al film needs to have a layer thickness of 0.5 μm or more as in Example 1, and the layer thickness is required to be 0.5 μm or more. , SiO with relatively high thermal conductivity₂Or it can be seen that it needs to be formed on Si.

【0090】

In addition to the above experiment, a damage prevention layer having the same configuration as that of Example 1, an Al film, and SiO₂Alternatively, an experiment was conducted by irradiating a laser beam on Si formed by sputtering. Also in this case, the damage prevention layer was not melted by the laser beam as in the first embodiment. Therefore, even if the crystal state of the Al film differs between the vapor-deposited film and the sputtered film, the layer thickness is 0.5 μm or more and SiO₂Alternatively, if formed on Si, the Al film has a damage preventing effect.

【0091】

In addition, SiO in which the damage prevention layer is formed₂Alternatively, Si is more preferable if the layer thickness is thick and the heat conduction effect is high. Also, SiO₂Alternatively, it may be a plating layer other than Si, such as Ni, which has a relatively high thermal conductivity. However, when the Al film is used not only as a damage prevention layer but also as a wiring, the wiring resistance changes due to the influence of the lower layer on which the Al film is formed, so it is necessary to consider the electrical resistance of the material of the lower layer. is there. In this case, the lower layer is preferably a metal film having a higher resistance than the Al film.

【0092】

In the above embodiment, an Al film is used as the damage prevention layer, but a metal film made of an alloy such as AlSi, AlSiCu, AlCu, AlNi, which has a high selectivity for laser ablation, may be used. When forming a semiconductor device, Ni, Ti, Co and the like are suitable metal film materials because they have a melting point close to that of silicon, which is often used as a substrate. Cr, Mo, Cu or the like may be used as the material of the metal film having a high selectivity with respect to other laser ablation.

【0093】

Further, the damage prevention layer forms a plurality of dielectric layers, and the plurality of dielectric layers optimizes the refractive index of the laser light to cause multiple reflection of the laser light to increase the reflectance of the laser light. It may be about 80% or more.

【0094】

[Effect of the invention]

As is clear from the above, the semiconductor device of the first invention includes a substrate having a semiconductor element, a processed layer provided on the substrate and the semiconductor element and processed by laser light, and the processed layer. And the damage prevention layer which is arranged between the semiconductor element or at least one of the substrates and reflects the laser light, the damage prevention layer reflects the laser light for processing the work layer. Therefore, the laser beam is prevented from reaching the semiconductor element. Therefore, this semiconductor device can be manufactured in a short time by the laser beam, and can prevent damage to the substrate and deterioration or destruction of the performance of the semiconductor element due to the laser beam during manufacturing, and can be a semiconductor device having good performance. ..

【0095】

In one embodiment, since the damage prevention layer has a reflectance of 80% or more with respect to the laser light, 80% or more of the laser light that goes beyond the work layer and is directed toward the substrate side is reflected toward the processed layer side. As a result, most of the laser light does not reach the semiconductor element, and deterioration or destruction of the performance of the semiconductor element can be effectively prevented.

【0096】

In one embodiment, since the damage prevention layer is a metal film, it is possible to effectively reflect the laser beam that goes beyond the work layer and toward the substrate side, effectively degrading or destroying the performance of the semiconductor element. Can be prevented.

【0097】

In one embodiment, since the metal film is an Al film having a relatively large reflectance to laser light, the laser light that exceeds the work layer and is directed toward the substrate side is reliably reflected by the Al film, and the semiconductor It is possible to reliably prevent deterioration and destruction of element performance.

【0098】

In one embodiment, since the Al film has a film thickness of 0.5 μm or more, even if the Al film is heated by the laser beam absorbed by the Al film without being reflected, the Al film is melted by this heat. There is no. Therefore, the damage prevention layer made of the Al film can stably prevent the laser beam from reaching the semiconductor element, and can reliably prevent the performance of the semiconductor element from deteriorating or being destroyed.

【0099】

In one embodiment, the damage prevention layer is composed of two or more layers, and the layer on the work layer side of the damage prevention layers is a reflective layer that reflects the laser light, and is a damage prevention layer. Since the layer on the semiconductor element side is an absorption layer that absorbs the laser beam, most of the laser beam directed toward the damage prevention layer when the layer to be processed is processed is reflected and absorbed, and the laser beam is reflected and absorbed. Since it hardly reaches the semiconductor element, deterioration or destruction of the performance of the semiconductor element can be reliably prevented.

【0100】

In one embodiment, since the reflection layer is a metal film and the absorption layer is a silicon layer, most of the laser light that has reached the damage prevention layer is reflected by the metal film, and further, the metal film is further reflected. Most of the laser light that has passed through the metal film without being reflected by the silicon layer can be absorbed by the silicon layer so that almost all the laser light does not reach the semiconductor element, resulting in deterioration or destruction of the performance of the semiconductor element. Can be reliably prevented.

【0101】

The semiconductor device of the second invention includes a substrate provided with metal wiring, a layer to be processed provided on the metal wiring and an opening formed in the metal wiring by laser light, and the substrate. Since it is arranged between the metal wiring and has a heat conductive layer having a higher thermal conductivity than the substrate, a part of the laser beam irradiated to the metal wiring becomes heat energy and the metal wiring generates heat. Even so, since this heat is quickly dissipated to the substrate by the heat conductive layer, the metal wiring does not accumulate heat due to the laser beam, and problems such as melting and peeling of the metal wiring can be prevented.

【0102】

In one embodiment, the metal wiring is made of Al, which has a relatively high reflectance to laser light, and the heat conductive layer is a silicon oxide film, a silicon nitride film, or a Ni film having a relatively high thermal conductivity. Therefore, even if the laser that has passed through the layer to be processed reaches Al, the amount of laser light absorbed by Al is relatively small and the amount of heat of Al is small, and the heat of Al is quickly transferred by the heat conductive layer. Since it is released to a portion other than Al, it is possible to reliably prevent melting and peeling of the metal wiring made of Al, and it is possible to stabilize the performance of the semiconductor device provided with this metal wiring.

【0103】

The method for manufacturing a semiconductor device of the third invention includes a step of providing a damage prevention layer on a substrate having a semiconductor element, a step of providing a layer to be processed on the substrate and the damage prevention layer, and a step of providing a layer to be processed on the damage prevention layer. Since the work layer is processed by the laser beam, the damage prevention layer can effectively prevent the semiconductor element from being irradiated with the laser beam when the work layer is processed by the laser light. The semiconductor device can be manufactured in a short time without damaging the substrate or deteriorating or destroying the performance of the semiconductor element.

[Simple explanation of drawings]

[Figure 1]

FIG. 1 (a) is a diagram showing an electronic component which is a semiconductor device according to the first embodiment of the present invention, and FIGS. 1 (b), (c), and (d) are the semiconductor devices of FIG. 1 (a). It is a figure which shows the manufacturing process of.

[Figure 2]

FIG. 2 (a) is a diagram showing an optical component as a semiconductor device according to the second embodiment of the present invention, and FIGS. 2 (b) and 2 (c) show the manufacturing process of the semiconductor device of FIG. 2 (a). It is a figure which shows.

[Fig. 3]

FIG. 3 (a) is a diagram showing a multilayer wiring board which is an electronic component as a semiconductor device according to the third embodiment of the present invention, and FIGS. 3 (b) and 3 (c) are the semiconductor of FIG. 3 (a). It is a figure which shows the manufacturing process of an apparatus.

[Fig. 4]

FIG. 4 (a) is a diagram showing an electronic component having a PN junction diode as a conventional semiconductor device, and FIGS. 4 (b), (c), and (d) are views of the semiconductor device of FIG. 4 (a). It is a figure which shows the manufacturing process.

[Fig. 5]

FIG. 5 (a) is a diagram showing an optical component having a photodiode and an optical waveguide as a conventional semiconductor device, and FIG. 5 (b) is a diagram showing a manufacturing process of the semiconductor device of FIG. 5 (a). is there.

[Fig. 6]

FIG. 6 (a) is a diagram showing a multilayer wiring board as a conventional semiconductor device, and FIGS. 6 (b) and 6 (c) are diagrams showing a manufacturing process of the semiconductor device of FIG. 6 (a).

[Explanation of symbols]

1 Semiconductor substrate 2 PN junction diode 3 Metal film pattern 4 Lower insulation layer 6 Wiring layer 7 Upper insulation layer 9 Connection wiring