Joining method and joining device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a joining method of irradiating a resin material with infrared rays to heat and cure, and particularly to a joining method and an apparatus suitable for irradiating a thermosetting resin with infrared rays to join a liquid crystal display panel and a drive circuit board. It is a thing.

【0002】

[Conventional technology]

The spread of liquid crystal display devices as image display devices for personal computers and other various monitors is remarkable. In general, this type of liquid crystal display device irradiates a liquid crystal surface having a predetermined spread with uniform brightness as a whole by disposing a backlight which is a planar light source for illumination on the back surface of the liquid crystal display panel. As a result, the image formed on the liquid crystal surface is configured to be a visible image. The liquid crystal display device includes a liquid crystal display panel formed by enclosing a liquid crystal material between two glass substrates, a printed circuit board for driving the liquid crystal material mounted on the liquid crystal display panel, and a liquid crystal display panel. It includes a backlight unit arranged on the back surface via a liquid crystal display panel holding frame, and an outer frame that covers them. TFT (Thin Film) in the liquid crystal display In the case of a Transistor (thin film) liquid crystal display device, one of the glass substrates constituting the liquid crystal display panel constitutes an array substrate, and the other glass substrate constitutes a color filter substrate. In addition to the TFT, display electrode, and signal line, which are the driving elements of the liquid crystal material, the array substrate is formed with a lead-out electrode for electrically connecting to the printed circuit board, and the TFT is regulated on the glass substrate. It is called an array substrate because it is aligned in a uniform manner. In addition to the color filter, a common electrode, a black matrix, and the like are formed on the color filter substrate. The printed circuit board is generally connected (mounted) to an extraction electrode formed on the array board via a TAB (Tape Automated Bonding) tape carrier (hereinafter, simply TAB). Then, the input lead conductor of the TAB is connected to the corresponding conductor of the printed circuit board by, for example, solder. On the other hand, the output lead conductor of the TAB is connected to the corresponding lead electrode of the array substrate. Traditionally, ACF (Anisotropic) has been used to connect the output lead conductor of the TAB to the corresponding lead electrode of the array board. Conductive Film (Anisotropic Conductive Paste) or ACP (Anisotropic Conductive Paste) is used. In addition to mounting using TAB, there is a mounting technology called COG (Chip On Glass). This COG is a technology for joining IC silicon chips (hereinafter referred to as silicon chips) on an array substrate by ACF or ACP.

【0003】

ACF or ACP (hereinafter, both are collectively referred to as ACF) is a substance in which particles made of a conductive material are dispersed in a resin as an adhesive, and is thermosetting with a thermoplastic ACF using a thermoplastic resin as an adhesive. There are two types of thermosetting ACF that use mold resin as an adhesive. The joining methods using thermoplastic ACF and thermosetting ACF are consistent in that they perform thermal pressurization with heating and pressurization. A specific example of this thermal pressurization joining method will be described with reference to FIG. FIG. 6 shows a main configuration of an apparatus for joining a silicon chip 121 with an ACF 124 on an array substrate 123 of a liquid crystal display panel 120 including an array substrate 123 provided with a polarizing plate 126 and a color filter 125, respectively. This joining device consists of a heater tool 111 and a backup block 116. The heater tool 111 has a built-in heater (not shown) inside. When joining the silicon chip 121 onto the array substrate 123, as shown in FIG. 6, the heater tool 111 is sandwiched between the heater tool 111 and the backup block 116 while holding the array substrate 123, the silicon chip 121, and the ACF 124. To heat. The heating of the heater tool 111 is conducted to the ACF 124 via the silicon chip 121. This heat conduction heats and cures ACF124. As a heating method, there is also an example of adopting a pulse heat method in which a large current of a low frequency pulse is applied to the heater tool 111 itself to generate heat instantaneously by utilizing the heat loss of the metal. The pulse heat method has an advantage that the degree of freedom of temperature / pressure profile is large.

【0004】

[Problems to be Solved by the Invention]

However, since the conventional joining method does not take into consideration the thermal expansion and contraction of the material, various problems occur in a large liquid crystal display panel, which requires a pinching pitch and a pinching frame. There is. One is the amount of shrinkage of the TAB or silicon chip after thermal expansion between the array substrate in contact with the adhesive ACF and the TAB or silicon chip when a mounting material formed of TAB formed of polyimide or the like or a silicon chip is mounted. The difference causes uneven mounting. The stronger the bonding force of the ACF, the greater the degree of this mounting unevenness. In particular, when mounting a silicon chip, the rigidity of the chip is higher than that of the TAB, so that it appears as a clear unevenness. This is a major factor in the fact that silicon chip mounting is not widely used as a mounting technology for large high-definition liquid crystal display panels. In the mounting of TAB, the rigidity of polyimide is sufficiently smaller than that of glass, so that it does not appear as remarkable mounting unevenness, but it has the same mounting unevenness mechanism as that of silicon chip mounting. FIG. 7 is a diagram for explaining the mechanism of mounting unevenness. In FIG. 7A, the heater tool 111 is a heater for heating the TAB or the silicon chip 121 by heat conduction. The silicon chip 121 is mounted on the array substrate 123 via the thermosetting ACF124. Here, for example, assuming that the temperature required to cure the ACF 124 is 210 ° C, the heating temperature of the heater tool 111 needs to be about 250 ° C. At this time, the temperature of the lower surface of the array substrate 123 is about 70 ° C. That is, a considerable temperature gradient is generated from the silicon chip 121 to the array substrate 123. FIG. 7B is a diagram showing the state of the cooling process after heating the ACF124. By the way, an object contracts when the temperature decreases, and the amount of contraction increases as the temperature difference before and after the temperature change increases. The silicon chip 121 contracts in the direction of the arrow at the top, and the array substrate 123 also contracts in the direction of the arrow at the bottom. The length of this arrow also indicates the magnitude of the amount of contraction. .. FIG. 7 (c) shows a state in which the ACF 124 is completely cured and the silicon chip 121 is bonded to the array substrate 123. At this time, since the heating temperature of the array substrate 123 is lower than the heating temperature of the silicon chip 121, the amount of shrinkage of the silicon chip 121 becomes large. Therefore, as shown in FIG. 7 (c), the silicon chip 121 and the array substrate 123 constrained by the ACF 124 are warped. Here, since the silicon chip 121 has a larger shrinkage amount, the silicon chip 121 is warped inward. In the future, if the array substrate 123 becomes thinner in response to the thinner liquid crystal display device, or if glass with low rigidity is used for the array substrate 123, the occurrence of warpage may be raised as a major mounting problem. is there.

【0005】

The second is that the color filter 125 and the like are damaged by the heating of the heater tool 111 because the heater tool 111 and the components of the liquid crystal display panel are brought close to each other due to the sandwiched frame. The heating temperature for curing the ACF124 is approximately 170 to 230 ° C, but the heating temperature of the heater tool 111 is set to be about 30 to 40 ° C higher than this. Therefore, a considerable amount of heat is applied to the liquid crystal material, the sealant, the color filter pigment, the polarizing plate, and the like of the liquid crystal display panel. This heat includes the possibility of deteriorating the liquid crystal material and the sealing agent.

【0006】

By the way, Japanese Patent No. 2568853 discloses a technique for curing a thermoplastic ACF by irradiating infrared rays as an electromagnetic wave. According to Japanese Patent No. 2568853, heat for curing the ACF is generated by irradiating the ACF with infrared rays. This has the potential to solve some of the problems described above. However, it does not disclose an effective method for the occurrence of warpage due to the temperature gradient. Further, since it is possible to cure by simply bringing the temperature to the curing point temperature, the joining method using a thermoplastic ACF is currently shifting to the joining method using a thermosetting ACF.

【0007】

Further, a technique for heating and curing ACF by irradiating infrared rays is disclosed in Japanese Patent Application Laid-Open No. 5-206220. However, the technique disclosed in Japanese Patent Application Laid-Open No. 5-206220 preheats TCP (tape carrier package), which is the object to be bonded by ACF, then irradiates infrared rays, and heats ACF by the heat generated there. Therefore, it involves the problem of temperature gradient. In addition, the technology of Japanese Patent Application Laid-Open No. 5-206220 is to coat TCP with a black carbon material to easily absorb infrared rays, or to add a similar coating material to the inside of ACF to make it easier to absorb infrared rays. I'm asking you to do something. This suggests that the heating efficiency of ACF by infrared irradiation is not sufficient, and that a special process needs to be newly added for coating or blending of coating material.

【0008】

Therefore, an object of the present invention is to provide a technique capable of suppressing the occurrence of warpage when joining using a thermosetting ACF. Another object of the present invention is to provide a technique capable of efficiently curing a thermosetting ACF without adding a new process.

【0009】

[Means for solving problems]

In the conventional joining method, the TAB or the silicon chip is heated by heat conduction, and the ACF is further heated by the heat conduction from the TAB or the silicon chip. To heat the ACF using heat conduction, it is also conceivable to heat the array substrate by heat conduction. However, since the glass constituting the array substrate has lower thermal conductivity than the TAB or silicon chip, the ACF can be heated more efficiently by heating the TAB or silicon chip than by heating the array substrate. Therefore, conventionally, the TAB or the silicon chip has been heated. However, heating the TAB or silicon chip means promoting a temperature gradient.

【0010】

When the array substrate is heated by conductive heat using the above-mentioned heater tool, efficient heating of ACF cannot be realized due to its low thermal conductivity. However, efficient heating can be achieved by irradiating a specific part of the array substrate with electromagnetic waves to self-heat and conduct the heat to the ACF. Moreover, if a part of the electromagnetic waves irradiated to the array substrate reaches the ACF, the ACF also generates heat by itself, and efficient curing of the ACF can be realized. The present invention is based on the above findings, and includes a step of disposing a thermosetting resin between a first member and a second member, and irradiating the thermosetting resin with an electromagnetic wave to perform the thermosetting. A step of joining the first member and the second member by heating and curing the mold resin is provided, and the second member absorbs a part of the first member when irradiated with the electromagnetic wave. It is a joining method characterized in that it is made of a material that transmits a part of the other material, and that the electromagnetic wave irradiated to the second member is transmitted and irradiated to the thermosetting resin. In the joining method of the present invention, an electromagnetic wave, for example, infrared rays is applied to a predetermined region of the second member. Since the second member is made of a material that absorbs a part of the second member when irradiated with the electromagnetic wave and transmits the other part, the second member self-heats due to the absorption of the electromagnetic wave. The radiant heat generated by this self-heating serves as a heat source for curing the thermosetting resin. Further, the electromagnetic wave transmitted through the second member is irradiated to the thermosetting resin, and the thermosetting resin also self-heats. That is, according to the present invention, the thermosetting resin is heated by the conduction heat from the second member and its own radiant heat, so that efficient heating and curing can be realized. When the joining method of the present invention is applied to the mounting method of the liquid crystal display panel described above, the first member corresponds to a TAB or a silicon chip, and the second member corresponds to an array substrate.

【0011】

In the joining method of the present invention, it is desirable to use near infrared rays as electromagnetic waves. Further, in the present invention, the thermosetting resin can be irradiated with electromagnetic waves after the first member is heated to a predetermined temperature. This is effective for heating the thermosetting resin more efficiently or for minimizing the temperature gradient in the first member to the second member.

【0012】

Further, the present invention includes a step of placing another member on a glass substrate via a thermosetting resin, and near infrared rays having a wavelength in the range of 800 to 1200 nm on the thermosetting resin via the glass substrate. Provided is a joining method comprising a step of irradiating and a step of cooling and curing the thermosetting resin heated by irradiation of the near infrared rays. In the bonding method of the present invention, when the wavelength of near infrared rays is in the range of 800 to 1200 nm, the absorption efficiency in the thermosetting resin is high, which is desirable for curing the thermosetting resin.

【0013】

In the bonding method of the present invention, when the glass substrate is irradiated with near-infrared rays, a part of the irradiated near-infrared rays is absorbed by the glass substrate and the glass substrate self-heats, and the other part of the near-infrared rays is transmitted through the glass substrate. Then, the heat-curable resin is irradiated. Thermosetting resin irradiated with near infrared rays generates radiant heat due to self-heating. Therefore, since the thermosetting resin is heated by the conductive heat from the glass substrate and the radiant heat generated by itself, efficient curing is realized.

【0014】

In the joining method of the present invention, it is important to control the temperature in the process of heating and then cooling the thermosetting resin. Thermosetting resins have the property of being cured by heating, but they are not completely cured immediately after the curing reaction begins. It has some flexibility in the cooling process after heating to a predetermined temperature, and complete curing is achieved in a temperature range below the glass transition temperature. Therefore, in the temperature range up to the glass transition temperature, the warp described with reference to FIG. 7 does not occur or is very slight. However, in the temperature range below the glass transition temperature, the warp becomes remarkable. Here, since the silicon chip 121 and the array substrate 123 have different specific heats, the cooling speeds when the silicon chips 121 and the array substrate 123 are heated to the same temperature and then allowed to cool are different. Specifically, the silicon chip 121 is cooled faster than the array substrate 123. Therefore, it is important to suppress the temperature difference between the silicon chip 121 and the array substrate 123 during the cooling process in order to prevent the occurrence of warpage. Therefore, in the present invention, the step of disposing the heat-curable resin between the first member and the second member, the step of heating to cure the heat-curable resin, and the heated heat-curing A joining method comprising a step of cooling a mold resin, and comprising performing a temperature difference suppressing process for suppressing a temperature difference between the first member and the second member in the cooling step. provide.

【0015】

In the joining method of the present invention, as a specific method of the temperature difference suppressing process, in the cooling step, cooling of either the first member or the second member is suppressed, or the cooling of the first member is suppressed. Cooling of either the member or the second member can be promoted. Of course, both suppression of cooling and promotion of cooling can be performed. For example, if the first member is a silicon chip 121 and the second member is an array substrate 123, the silicon chip 121 is cooled, and the array substrate 123 is controlled to be cooled. The temperature difference between 121 and the array substrate 123 can be suppressed. Then, in performing the temperature difference suppressing process, the temperature of at least one of the first member and the second member can be detected, and the temperature difference suppressing process can be performed based on the detected temperature. This temperature detection may be detected directly from the first member and the second member, or may be indirectly detected.

【0016】

In the joining method of the present invention, it is possible to promote the cooling of the member having a large heat capacity among the first member and the second member, and to suppress the cooling of the member having a small heat capacity. In this way, it is possible to perform a temperature difference suppressing process such as promoting or suppressing cooling in consideration of the heat capacity. Further, in the joining method of the present invention, the temperature difference suppressing treatment in the cooling step is performed in the temperature range from the temperature heated by the heating step to the glass transition temperature of the thermosetting resin. The amount of shrinkage between the second member and the second member can be made equal. By doing so, the temperature difference between the first member and the second member disappears when the glass transition temperature range is reached during cooling, and as a result, the first member and the first member below the glass transition temperature are eliminated. A temperature difference suppressing process can be performed so that a difference in the amount of shrinkage with the second member does not occur.

【0017】

The present invention provides the following devices that realize the above joining method according to the present invention. That is, the joining device of the present invention is a joining device that heats and cures an adhesive made of a heat-curable resin to join the first member and the second member as an object to be joined, and the adhesive. A light source that generates near-infrared rays for heating, a support base that has a near-infrared ray transmitting region that transmits near-infrared rays generated from the light source and supports the bonded object, and the first member and / or It is characterized by including a heater for heating the second member and a cooling mechanism for cooling the first member and / or the second member. Here, this heater can suppress the temperature difference between the first member and the second member in the cooling process by suppressing the cooling of the first member in the cooling process. Further, the cooling mechanism in the joining device of the present invention further cools the second member in order to prevent the heating of the portion of the second member that does not want to be heated, and the first member and the second member in the cooling process. The temperature difference can be suppressed. According to the joining device of the present invention, a support base having a region for transmitting near infrared rays is provided. Therefore, in a state where the array substrate on which the TAB or the silicon chip is placed is supported by the member to be joined by the support, for example, the thermosetting ACF, as an adhesive through the near-infrared ray transmitting region of the support. The thermosetting ACF can be irradiated with near infrared rays.

【0018】

In the joining device of the present invention, the adhesive is irradiated with near infrared rays transmitted through the near infrared ray transmitting region of the support base, and radiant heat can be generated by the irradiation. Further, the joining device of the present invention is a thermosetting resin in a state where a thermosetting resin as an adhesive is arranged between a first member and a second member made of a material that transmits near infrared rays. It irradiates near-infrared rays, and the second member is placed facing the support base, and the near-infrared rays that have passed through the near-infrared ray transmission region of the support base further pass through the second member and are thermosetting resin. The thermosetting resin can be heated by being irradiated with infrared rays and generating radiant heat by the irradiation. Further, the joining device of the present invention can be provided with a shutter that regulates the irradiation region of near infrared rays emitted from the light source. It is effective for irradiating near infrared rays only where necessary.

【0019】

As a specific application example of the joining method of the present invention, there is mounting on a liquid crystal display panel. Therefore, the present invention includes a step of disposing a thermosetting resin between a silicon chip and a glass substrate, a step of heating the silicon chip to a predetermined temperature, and irradiating the glass substrate with near infrared rays to irradiate the glass. The step of heating the thermosetting resin by near infrared rays transmitted through the substrate and the glass substrate, and the heated silicon chip, the thermosetting resin, and the glass substrate are combined with the silicon chip in a predetermined temperature range. Provided is a joining method including a step of cooling so as to suppress a temperature difference with the glass substrate.

【0020】

In the joining method of the present invention, it is desirable that the predetermined temperature range is close to the temperature at which the curing reaction of the thermosetting resin is completed. Further, in the present invention, the cooling step can suppress the temperature difference between the silicon chip and the glass substrate by suppressing the cooling of the silicon chip and promoting the cooling of the glass substrate.

【0021】

In the bonding method of the present invention, it is desirable that the temperature difference between the silicon chip and the glass substrate is substantially zero in the vicinity of the temperature at which the curing reaction of the thermosetting resin is completed.

【0022】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. First, the configuration of the panel mounting device according to the present embodiment shown in FIG. 1 will be described. The panel mounting device shown in FIG. 1 is a device for mounting the silicon chip 21 on the liquid crystal display panel 20. Here, in the liquid crystal display panel 20, an array substrate 23 in which the polarizing plate 26 is arranged on the lower surface and a color filter 25 in which the polarizing plate 26 is arranged on the upper surface are laminated at a predetermined interval. .. A bump 22 made of Au is formed on the lower surface of the silicon chip 21. The bump 22 provides an electrical connection between the silicon chip 21 and a lead-out electrode (not shown) formed on the array substrate 23. The bonding between the silicon chip 21 and the array substrate 23 is performed by a thermosetting ACF24. The panel mounting device shown in FIG. 1 is for curing the heating / pressurizing mechanism 10 that heats and pressurizes the silicon chip 21, the near-infrared irradiation mechanism 30 for irradiating the near-infrared ray 36, and the thermosetting ACF24. It is composed of a cooling mechanism for cooling the heat generated in the infrared.

【0023】

The heating / pressurizing mechanism 10 is composed of a pressurizing block 11, a heat insulating material 12, a heater tool 13, a pressure cushioning material 14, a holding block 15 made of industrial quartz glass, and a backup block 16. The pressurizing block 11 is a block for crimping the silicon chip 21 which is a mounting material to the array substrate 23. It is desirable to use hardened special steel having a small coefficient of linear expansion for the pressure block 11. The heat insulating material 12 thermally shuts off the heater tool 13 and the pressure block 11. More specifically, it is for preventing the pressure block 11 and the mechanism for driving the pressure block 11 from being distorted due to thermal expansion, and a porous ceramic can be used. However, other materials can be used as long as they are made of a material having high rigidity, high heat insulation, and less deformation and distortion.

【0024】

The heater tool 13 is a heating means for preheating or supplementing the silicon chip 21. Preheating and reheating will be described in detail later. The heater tool 13 is a small constant heater having a planar vapor deposition heater formed in the center. For the substrate, it is desirable to use ceramics that have a fast heating and cooling reaction, are highly rigid, and have little strain due to heat or pressure. A pressure cushioning material 14 is provided between the heater tool 13 and the silicon chip 21 to be heated. The pressure cushioning material 14 is less necessary when joining a TAB having a certain degree of cushioning ability against height variation to the array substrate 23. However, in joining high-rigidity materials such as the silicon chip 21 and the array substrate 23, mutual surface accuracy cannot be ensured due to the waviness of each joining surface. In that case, non-uniform pressure occurs between the silicon chip 21 and the array substrate 23, which causes poor connection. The pressure cushioning material 14 is for avoiding this connection failure, and may be any material that can apply a uniform surface pressure to the pressure-bonded surface due to its elasticity. As a specific material, a material based on silicon rubber, an aramid tape, a polyimide film (for example, Kapton manufactured by DuPont) or the like can be used.

【0025】

The heating / pressurizing mechanism 10 is provided with a support block 15 that directly supports the liquid crystal display panel 20 and a backup block 16 that supports the support block 15. The support block 15 is made of industrial quartz glass, and the near infrared rays 36 emitted from below can pass through the support block 15 and reach the array substrate 23. As the industrial quartz glass, it is desirable that the quartz glass transmits near infrared rays 36 and has a small thermal conductivity, and for example, "Pyrex" (trade name) can be adopted. For the backup block 16, it is desirable to use a highly rigid metal having good thermal conductivity and a small coefficient of linear expansion.

【0026】

Next, the near-infrared irradiation mechanism 30 will be described. The near-infrared irradiation mechanism 30 includes a lamp 31 that is a light source of the near-infrared ray 36, a reflector 32 that receives and reflects the near-infrared ray 36 emitted from the lamp 31, and a shutter that allows light reflected from the reflector 32 to pass through. I / R (Infrared) that controls the irradiation of near infrared rays 36 from the mask 33 and the lamp 31 Rays) It consists of a unit controller 34 and a heat exchanger 35. The near-infrared ray 36 emitted from the lamp 31 is irradiated to the array substrate 23 and the thermosetting ACF 24 via the reflector 32 and the support block 15. It is desirable that the near-infrared ray 36 has a wavelength in the range of 800 to 1200 nm, as will be described in detail later. In the present embodiment, a quartz infrared halogen lamp in which a filament is arranged in the center of a quartz glass tube as a lamp 31 and a halogen is sealed as an inert gas is used. The reflector 32 having a parabolic reflecting surface reflects the near infrared rays 36 emitted from the lamp 31 as described above. Therefore, the lamp 31 is placed on the focal point of the reflector 32. A slit having a predetermined width is formed in the shutter mask 33. Therefore, only the near infrared rays 36 that have passed through this slit are irradiated to the array substrate 23. That is, the shutter mask 33 has a function of irradiating the near infrared rays 36 only to the portion of the array substrate 23 that requires heating for bonding. The shape and size of the slit of the shutter mask 33 are not particularly limited, and may be appropriately set according to the shape and area of the portion requiring heating. Of course, a plurality of different shutter masks 33 can be prepared and replaced for each joint target. Further, as the material of the shutter mask 33, stainless steel, aluminum, chrome-plated glass or the like that does not absorb infrared rays can be used. The I / R unit controller 34 is a means for generating the near-infrared ray 36 and keeping the output of the near-infrared ray 36 emitted from the lamp 31 constant. Therefore, the I / R unit controller 34 incorporates a control circuit and a power supply for controlling the current flowing through the filament of the lamp 31 to obtain an appropriate temperature profile. The heat exchanger 35 is a cooling mechanism in which the entire near-infrared irradiation mechanism 30 is incorporated in a circulation type cooling device.

【0027】

Next, a cooling mechanism for cooling the heat generated in the mounting apparatus according to the present embodiment will be described. The cooling mechanism includes cooling nozzles 41a, 41b, 41c, a heat sink 42, and cooling fins 43. The cooling nozzle 41a is provided to prevent the heat generated by the heater tool 13 from being conducted to the polarizing plate 26 via the pressure cushioning material 14. Further, the cooling nozzles 41b and 41c are provided to prevent the heat generated in the array substrate 23 from being conducted to the color filter 25 and the polarizing plate 26 by being irradiated with the near infrared rays 36. If the color filter 25 or the polarizing plate 26 is heated to a predetermined temperature or higher, deformation or deterioration may occur. It also has the effect of preventing peripheral members other than the polarizing plate 26 from being altered by the heat. The cooling nozzles 41a, 41b, and 41c achieve the above-mentioned cooling purpose by ejecting a cooling gas from the tip thereof. The gas to be ejected may be a cooled gas or a normal temperature gas as long as the purpose can be achieved. The heat sink 42 is provided to prevent heat generated by irradiating the array substrate 23 with the near infrared rays 36 from being conducted to the polarizing plate 26 arranged below the array substrate 23. Further, the cooling fin 43 is for radiating the heat generated by the near-infrared irradiation mechanism 30 described above to the outside.

【0028】

The heater tool 13 is formed with cooling holes 44a, and the support block 15 is formed with cooling holes 44b and 44c. Therefore, the cooling holes 44a to 44c also form a cooling mechanism. The heater tool 13 is cooled by supplying the cooling medium to the cooling holes 44a, and the support block 15 is cooled by supplying the cooling medium to the cooling holes 44b and 44c. The cooling medium supplied to these cooling holes 44a, 44b, 44c is not limited, but air is desirable in consideration of ease of control, ease of device structure, and the like. The temperature of the heater tool 13 is detected by the temperature sensor 45a, and the temperature of the support block 15 is detected by the temperature sensor 45b. The temperature measured by the temperature sensors 45a and 45b may be directly detected by the temperature of the silicon chip 21 or the array substrate 23, or may be indirectly detected via the heater tool 13 or the support block 15. And. The temperature profile in the heater tool 13 and the support block 15 is controlled by changing the flow velocity of the air supplied to the cooling holes 44a, 44b, 44c according to the temperature information from the temperature sensors 45a and 45b. Controlling this temperature profile means controlling the temperature of the silicon chip 21 and the array substrate 23. Further, the cooling holes 44b and 44c suppress the temperature difference generated between the silicon chip 21 and the array substrate 23 due to the rapid cooling of the silicon chip 21 due to cooling. That is, the temperature difference can be suppressed by promoting the cooling of the array substrate 23, and the problem of warpage due to the difference in the amount of shrinkage, which will be described in detail later, can be solved.

【0029】

Next, the implementation process in the present embodiment will be described with reference to the flowcharts shown in FIGS. 1 and 2. First, the mounted object and the mounted object are set in the panel mounting device. That is, the liquid crystal display panel 20 is set on the support block 15 with the silicon chip 21 placed on the array substrate 23 via the thermosetting ACF24. Further, the heater tool 13 attached to the pressure block 11 is brought into contact with the silicon chip 21 via the pressure cushioning material 14 (referred to as S101 in FIG. 2; the same applies hereinafter).

【0030】

Next, the heater tool 13 is heated. Then, the silicon chip 21 is heated by heat conduction through the pressure cushioning material 14 (FIG. 2). S102). This heating will be called preheating. By preheating the silicon chip 21, the temperature gradient from the silicon chip 21 to the array substrate 23 can be reduced. This preheating is due to heat conduction heating. Heat conduction heating is a phenomenon in which molecules in contact with a heated substance are excited by the heat energy to generate heat. That is, heat conduction is heat generation due to the transfer of heat energy, that is, the temperature from the outside. The heat conduction heating in the present embodiment is due to the heat energy generated by the heater tool 13 exciting the molecules constituting the silicon chip 21 to generate heat. This heat excites adjacent molecules one after another, heating the entire silicon chip 21. In addition, heat conduction occurs from the silicon chip 21 to the thermosetting ACF24, and the thermosetting ACF24 is also heated. Since the heat conduction heating by the heater tool 13 is performed via the pressure cushioning material 14, the pressure cushioning material 14 is also heated. Heat conduction heating also occurs in the heated pressure cushioning material 14 and tries to spread over the entire pressure cushioning material 14. However, in the present embodiment, the cooling gas is cooled by the cooling gas ejected from the cooling nozzle 41a. Therefore, it is possible to avoid the problem that the heat transferred to the pressure cushioning material 14 by the heat conduction heating from the heater tool 13 deforms and alters the polarizing plate 26 arranged on the color filter 25.

【0031】

When the silicon chip 21 reaches a predetermined temperature by preheating, the lamp 31 emits near infrared rays 36 (Fig. 2 S103). The near-infrared ray 36 emitted from the lamp 31 located at the focal point of the reflector 32 is reflected and focused by the reflector 32. The reflected and condensed near-infrared rays 36 reach the array substrate 23 after the shutter mask 33 blocks the transmission of the near-infrared rays 36 to the portion of the array substrate 23 other than the portion requiring bonding. A part of the near infrared rays 36 that have reached the array substrate 23 is absorbed by the array substrate 23, but the other part passes through the array substrate 23 and reaches the thermosetting ACF24.

【0032】

Here, when the array substrate 23 is irradiated with the near infrared rays 36, radiant heat is instantaneously generated. Radiant heat is a phenomenon in which the intermolecular bonds of a substance are loosened by radiating a certain electromagnetic wave (microwave) to the substance, and the molecules are excited to generate heat. It is known that the wavelength of an electromagnetic wave takes a unique value depending on the molecular binding structure of a substance. The radiant heat generated in the array substrate 23 tries to be conducted to the portion other than the portion irradiated with the near infrared rays 36. However, in the present embodiment, the heat sink 42 always dissipates this conducted heat, and the heat sink 42 is cooled by the cooling gas ejected from the cooling nozzles 41b and 41c. By dissipating heat and cooling in this way, the polarizing plate 26 arranged in the lower part of the array substrate 23 is not deformed or burnt by the radiant heat generated in the array substrate 23. In addition to the polarizing plate 26, it is also possible to prevent heat from being conducted to the color filter 25 and deteriorating.

【0033】

Here, the present embodiment is characterized in that the near infrared ray 36 is used. The conventional thermosetting ACF has a higher absorption rate for visible light and ultraviolet light having a short wavelength. However, as a heat source for generating radiant heat, near-infrared light is easy to handle and can be easily controlled. Further, in order to suppress the heat gradient, heat generation is required in the array substrate 23 made of glass. For these reasons, in the present embodiment, near infrared rays, particularly near infrared rays 36 having a wavelength in the range of 800 to 1200 nm are used. Then, the near infrared rays 36 that have passed through the array substrate 23 and reached the thermosetting type ACF24 can generate radiant heat in the thermosetting type ACF24 to efficiently heat the thermosetting type ACF24. On the other hand, the radiant heat generated on the array substrate 23 is conducted to the thermosetting ACF24 in contact with the array substrate 23. That is, the thermosetting ACF24 is heated by heat conduction heating from the array substrate 23. In this way, the thermosetting ACF24 can simultaneously receive radiant heat heating by irradiation with near infrared rays 36 and heat conduction heating from the array substrate 23.

【0034】

As described above, the thermosetting ACF24 is heated by the radiant heat generated by the thermosetting ACF24 itself and the conduction heat from the array substrate 23 (Fig. 2 S104). When the thermosetting ACF24 is heated to a predetermined temperature, the irradiation of near infrared rays 36 is terminated. Next, the silicon chip 21 and the array substrate 23 are crimped by applying pressure to the silicon chip 21 by the pressure block 11 (FIG. 2 S105). After that, the silicon chip 21, the thermosetting ACF24, and the array substrate 23 are each cooled to room temperature (Fig. 2 S106). Here, since the glass chips constituting the silicon chip 21 and the array substrate 23 have the same shrinkage amount with respect to substantially the same temperature, the shrinkage amount can be made uniform if there is no temperature difference. Therefore, in this cooling process, in order to equalize the shrinkage amount of the silicon chip 21 and the shrinkage amount of the array substrate 23, a temperature difference does not occur between the silicon chip 21 and the array substrate 23. After the thermosetting ACF24 is cured, the silicon chip 21 and the array substrate 23 are electrically conductive by the conductive particles contained in the thermosetting ACF24.

【0035】

According to this embodiment, the silicon chip 21 is preheated, and the radiant heat generated in the array substrate 23 is used for heating the thermosetting ACF24. Therefore, the temperature gradient from the silicon chip 21 to the array substrate 23 can be suppressed. This will be explained in detail with reference to FIG. Since the array substrate 23 itself generates radiant heat due to the irradiation of the near infrared rays 36, the temperature gradient in the thickness direction does not occur in the array substrate 23, or if it does occur, it is slight. As shown in FIG. 3A, the temperature on the front and back surfaces of the array substrate 23 when no temperature gradient is generated is T1. Further, since the heat-curable ACF24 is heated by the radiant heat of the near infrared rays 36 transmitted through the array substrate 23 in contact with the heat-curable ACF24 and further heated by the conduction heat from the array substrate 23, the temperature is equivalent to the temperature of the array substrate 23. Can be regarded as. That is, the temperature of the front and back surfaces of the thermosetting ACF24 is also T1. Further, the silicon chip 21 is preheated, and the preheating temperature T2 can be set so that the difference from T1 is minimized. Here, since heat conduction occurs from the thermosetting ACF24 to the silicon chip 21, the preheating temperature is set in consideration of the heating of the silicon chip 21 by this conduction heat. As described above, while the silicon chip 21 is preheated by the heater tool 13, the silicon chip 21 to the array substrate 23 are heated by the radiant heat of the thermosetting ACF24 itself and the conduction heat based on the radiant heat of the array substrate 23. The temperature gradient can be reduced. On the other hand, in the past, only the conduction heat generated by the heater tool 111 was used, so that a large temperature gradient was generated from the silicon chip 121 to the array substrate 123.

【0036】

FIG. 3 (b) is a diagram showing a cooling process after heating. At the beginning of cooling, as described in the explanation of FIG. 3A, the temperature gradient from the silicon chip 21 to the array substrate 23 is small. Then, as described later, by reducing the temperature difference between the silicon chip 21 and the array substrate 23 in the cooling process, the shrinkage amount of the silicon chip 21 and the shrinkage amount of the array substrate 23 are shown by the arrows in FIG. 3 (b). Can be equalized. When the amount of shrinkage is uniform, it is possible to suppress the occurrence of warpage of the array substrate 23 on which the silicon chip 21 is mounted, as shown in FIG. 3 (c).

【0037】

Next, the behavior of the silicon chip 21, the thermosetting ACF24, and the array substrate 23 during heating will be described in detail with reference to FIG. In FIG. 4, the white arrow indicates the direction of heat conduction, and the dotted arrow indicates the near infrared 36. In addition, the color of each part represents the temperature, and the darker the color, the higher the temperature. First, as shown in FIG. 4A, the silicon chip 21 and the thermosetting ACF24 are preheated by heat conduction from a heater tool 13 (not shown). Next, as shown in FIG. 4 (b), the array substrate 23 self-heats due to the radiant heat generated by the irradiation of the near infrared rays 36. Further, as shown in FIG. 4 (c), the thermosetting ACF24 self-heats due to the radiant heat generated by the irradiation of the near infrared rays 36 transmitted through the array substrate 23. Furthermore, as shown in FIG. 4 (d), the thermosetting ACF24 is heated by heat conduction from the self-heated array substrate 23. At this time, as shown in FIG. 4 (e), heat conduction is generated from the thermosetting ACF24 to the silicon chip 21, and the silicon chip 21 is also heated to a predetermined temperature by this conduction heat.

【0038】

Here, since the temperature of the silicon chip 21 rises more easily than that of the glass forming the array substrate 23, it is more efficient to heat the silicon chip 21 to a predetermined temperature than the array substrate 23. Therefore, in order to reduce the temperature gradient from the silicon chip 21 to the array substrate 23, preheating the silicon chip 21 with the heater tool 13 is effective in improving the temperature gradient suppressing effect. Further, by using the conduction heat from the self-heated array substrate 23, the self-heat of the thermosetting ACF24, and the preheating by the heater tool 13, highly efficient and uniform heating is realized.

【0039】

The preheating by the heater tool 13 in the present embodiment is sufficient at a lower temperature than the case where the thermosetting ACF124 is heated only by the conventional heater tool 111, and the cooling nozzle 41a cools the polarizing plate 26. The effect of heat can be blocked. Further, by providing the cooling nozzles 41b, 41c, the heat sink 42, and the cooling holes 44a, 44b, 44c, the thermal influence on the liquid crystal display panel 20 can be minimized. Furthermore, by providing the pressure cushioning material 14, it is possible to uniformly pressurize the array substrate 23 of the silicon chip 21.

【0040】

Next, the behavior during cooling will be described in detail with reference to FIG. As described above, the thermosetting resin has a property of being cured by heating, but it is not completely cured immediately after the curing reaction starts. It has a certain degree of flexibility in the cooling process after heating to the curing point temperature, which is a predetermined temperature, and complete curing is achieved in a temperature range below the glass transition temperature. Therefore, in the temperature range up to the glass transition temperature, the warp described with reference to FIG. 7 does not occur or is very slight. However, in the temperature range below the glass transition temperature, the warp becomes remarkable. Therefore, again, in the present embodiment, it is important to suppress the temperature difference between the silicon chip 21 and the array substrate 23 in the cooling process.

【0041】

In FIG. 5, the solid white arrow indicates the heat replenishment by the heater tool 13, and the dotted white arrow indicates the cooling by the cooling holes 44b and 44c. Further, as in FIG. 4, the color of each part represents the temperature, and the darker the color, the higher the temperature. First, as shown in FIG. 5A, the silicon chip 21, the thermosetting ACF24, and the array substrate 23 are heated to the maximum heating temperature. Here, if the silicon chip 21 is allowed to cool, the silicon chip 21 cools faster than the array substrate 23 because of its small specific heat. Therefore, there is a difference in the amount of shrinkage between the silicon chip 21 and the array substrate 23, and warpage occurs. Therefore, in the present embodiment, the silicon chip 21 is heated by the heater tool 13 in order to prevent the silicon chip 21 from being rapidly cooled. This heating is supplementary heat. On the other hand, since the array substrate 23 made of glass cools slower than the silicon chip 21, air is circulated through the cooling holes 44b and 44c to promote the cooling of the array substrate 23, and the array substrate 23 and the silicon chip 21 are cooled. Suppress the temperature difference. As shown in FIG. 5 (b), the silicon chip 21, the thermosetting ACF24, and the array substrate 23 are cooled while supplementing the heat of the silicon chip 21 and promoting the cooling of the array substrate 23 to suppress the above temperature difference. Progresses. Then, as shown in FIG. 5C, the silicon chip 21, the thermosetting ACF24, and the array substrate 23 are cooled to room temperature while continuing the heat supplementation and cooling promotion for suppressing the temperature difference. In the present embodiment, as described above, in the cooling process, the temperature difference between the silicon chip 21 and the array substrate 23 is suppressed, preferably the temperature difference is substantially zero, so that warpage occurs. Can be prevented.

【0042】

In the above example, the process of suppressing the temperature difference, which comprises reheating the silicon chip 21 and promoting the cooling of the array substrate 23, is performed throughout the cooling process. However, as can be understood from the explanations so far, it is particularly important to control the glass transition temperature at or near the glass transition temperature at which the thermosetting resin constituting the thermosetting ACF24 ends its curing reaction in the cooling process. Therefore, in the temperature range considerably exceeding the glass transition temperature, the treatment for suppressing the temperature difference is not always necessary. However, since it is not easy to suppress the temperature difference after the temperature difference is excessively generated, it is desirable to perform the temperature difference suppressing process from the beginning as in the present embodiment. By controlling the temperature from the beginning, the amount of shrinkage of the silicon chip 21 and the array substrate 23 can be made equal in the cooling process up to the glass transition temperature, and the silicon chip 21 and the array substrate 23 can be even in the temperature range below the glass transition temperature. The amount of shrinkage can be equalized. Further, in the above-described embodiment, the silicon chip 21 and the array substrate 23 are taken as examples of the members to be joined, but the present invention is not limited to this, and can be universally applied to members made of other materials. it can.

【0043】

[Effect of the invention]

As described above, according to the present invention, since the temperature gradient between the members to be joined can be reduced, the occurrence of warpage can be suppressed. Further, by utilizing the radiant heat heating and the heat conduction heating generated by the irradiation of near infrared rays, it becomes possible to accelerate the curing reaction of the thermosetting resin.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the panel mounting apparatus in this embodiment.

[Figure 2]

It is a flowchart which shows the process for joining a mounting object and a mounted object in this embodiment.

[Fig. 3]

It is a figure for showing the temperature gradient and thermal expansion in this embodiment.

[Fig. 4]

It is a figure for demonstrating the effect at the time of heating by this embodiment.

[Fig. 5]

It is a figure for demonstrating the effect at the time of cooling by this embodiment.

[Fig. 6]

It is a figure for exemplifying the conventional joining method.

[Fig. 7]

It is a figure for demonstrating the mechanism of unevenness at the time of shrinkage by the difference of temperature gradient and thermal expansion in the conventional joining method.

[Explanation of symbols]

11 ... Pressurized Block, 12 ... Insulation, 13 ... Heater Tool, 14 ... Pressure Cushioning, 15 ... Support Block, 16 ... Backup Block, 21 ... Silicon Chip , 22 ... IC chip Au bump, 23 ... array substrate, 24 ... heat-curable ACF (anisometric conductive film), 25 ... color filter (CF: Color Filter), 26 ... Polarizer, 31 ... Lamp, 32 ... Reflector, 33 ... Shutter Mask, 34 ... I / R (Infrared Rays) Unit Controller, 35 ... Heat Exchanger, 36. .. Near infrared, 41a, 41b, 41c ... Cooling nozzle, 42 ... Heater, 43 ... Cooling fin, 44a, 44b, 44c ... Cooling hole, 45a, 45b ... Temperature sensor