JPH09162235A - Method for packaging ic chip and member for connecting ic chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the inspection/replacement of IC chip while intending the effective recycling of the liquid crystal panel. SOLUTION: Within this packaging method comprising conductive particles and thermomelting adhesive, after the connection by heating pressurizing steps, an IC chip is tack set connected to a substrate using a connecting member having the conductivity in the pressurizing direction and after inspection step the IC chip is regularly connected to the substrate at the setting temperature of said thermomelting adhesive. At this time, the IC chip is tack set connected in the set reaction rate not exceeding 20% and at the temperature in the melt viscosity not exceeding 5000 poise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC chip mounting method and a connecting member used in the method.

[0002]

2. Description of the Related Art The mounting technology of a connecting member composed of conductive particles and a heat-melting adhesive, that is, an IC chip using an anisotropic conductive adhesive, can be reduced in size and cost in a mounting field of a liquid crystal panel, for example. It is receiving attention as a method (COG method).

In this COG process, it is important to repair the expensive liquid crystal panel and replace only the chip. However, since the anisotropic conductive adhesive generally contains a thermosetting resin as a main component, after the main connection is made. However, there was a problem that the repair was extremely difficult in principle.

Therefore, in Japanese Patent Laid-Open No. 4-62946, an IC chip is inspected in a semi-hardened temporary connection state (in an electrically conductive state) with a connection resin, and after confirming the operation state of the chip, the resin is Since it is mounted in the main connection state at the curing temperature of 1, the mounting method is proposed in which if the chip does not operate normally, it can be removed and replaced in the temporary curing connection state.

[0005]

However, in this method, since there is no detailed disclosure of the characteristics of the resin constituting the connecting resin, when the chip is inspected in the temporarily cured connection state, the curing reaction of the main connection is performed. Not to adversely affect
If the connection resin is temporarily cured at a low temperature for a short time, it becomes difficult to establish an electrical conduction state, and there is a problem that the chip cannot be inspected.

[0006] On the other hand, there is a problem that if the chips are temporarily cured at a high temperature in order to easily establish an electrical conduction state, it becomes difficult to peel off the chips, which adversely affects the main connection.

The present invention has been made in view of the above circumstances, and mounting of an IC chip which facilitates chip inspection at the time of temporary curing connection and facilitates chip replacement at the time of chip failure. It is an object to provide a method and a connecting member used in the method.

[0008]

In order to achieve the above object, the present invention provides a connecting member which is composed of conductive particles and a thermofusible adhesive and has conductivity in the pressing direction after connection by heating and pressing. In the mounting method of an IC chip, the IC chip is inspected by a temporary curing connection to the substrate and then the IC chip is permanently connected to the substrate at a curing temperature of the connecting member. It is characterized by containing a phenoxy resin, an epoxy resin and a latent curing agent, and performing temporary curing connection at a temperature at which the curing reaction rate of the hot-melt adhesive is 20% or less and the melt viscosity is 5000 poise or less.

In the present invention, the conductive particles are, for example, Au, A
g, Cu, solder, or other metal particles, or polystyrene, or other polymeric spherical core material with Ni, Cu, Au,
It is more preferable to provide a conductive layer such as solder.

Further, Sn, Au,
It is also possible to form a surface layer of solder or the like. The particle size must be smaller than the minimum distance between the electrodes on the substrate, and if there are variations in the height of the electrodes, it is preferably larger than the variations in height. Smaller size is preferable to fit in the electrode. 1
μm to 10 μm is preferable.

The amount of conductive particles dispersed in the adhesive is
It is 0.1 to 30% by volume, preferably 0.2 to 15% by volume.

The epoxy resin used in the present invention is mainly composed of high molecular weight epoxy, solid epoxy, liquid epoxy, epoxy modified with acrylic rubber, urethane, polyester, nylon and the like, a curing agent, a curing accelerator, a cup. A material obtained by adding a ring agent, a filler, etc. is generally used. As the phenoxy resin of the present invention, bisphenol A-type, F-type, and AD-type resins are used. Since the phenoxy resin has a structure similar to that of the epoxy resin, it has characteristics such as excellent compatibility and adhesiveness with the epoxy resin. . Furthermore,
Due to their high cohesive force, these phenoxy resins retain a sufficient pressure contact force at the connecting portion even after a lapse of 2 to 3 days after the temporary curing connection, and thus have a characteristic that a stable electrical conduction state can be obtained.

The latent curing agents include imidazole type, hydrazide type, boron trifluoride-amine complex, sulfonium salts, amine imides, polyamine salts, dicyandiamide, and modified compounds thereof, which may be used alone or in admixture. It can be used as a mixture of two or more species. These are so-called catalyst type curing agents such as anionic or cationic polymerization type, and are easy to obtain fast curing property. Also, as a curing agent,
In addition, polyamines, polymercaptans, polyphenols, acid anhydrides, and other polyaddition types can be applied and the catalyst type curing agents can be used in combination.

In the connection member of the present invention, the adhesive composition comprising at least an epoxy resin, a phenoxy resin and a latent curing agent and conductive particles are liquefied by dissolving or dispersing in an organic solvent and applied on a peelable substrate. It is produced as a film by removing the solvent below the activation temperature of the curing agent. As the solvent used at this time, a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type is preferable because the solubility of the material is improved.

When the electrode pitch of the chips to be connected is small, a connecting member formed by laminating a film containing conductive particles and a film not containing conductive particles is used, and if the film side containing conductive particles is arranged on the substrate side, it is added from the chip side. Since the conductive particles can be efficiently captured on the electrode during connection by pressure and heating,
This is advantageous because the number of conductive particles between the electrodes is reduced, and as a result, a connection without a short circuit can be performed even at a minute connection pitch. As a method for laminating a film containing conductive particles and a film not containing conductive particles, there is a method in which each film is prepared and then laminated, or one of the films is prepared, and then the adhesive composition is sequentially applied. The curing reaction rate of the connection member is measured by DSC measurement.

That is, the heat-melting adhesive is wrapped in aluminum foil, sealed, and immersed in an oil bath set to a predetermined temperature for a predetermined time.
It was measured using C, and the curing reaction rate was calculated according to the equation (1). Curing reaction rate = [(Q ₀ −Q _T ) / Q ₀ ] × 100 (%) (1) where Q ₀ is the untreated heat value (J / g) and Q _T is the value after treatment. Indicates the amount of heat generation (J / g).

Temporary curing connection can be performed at a temperature where the curing reaction rate is 20% or less and the melt viscosity is 5000 poise or less. The melt viscosity can be measured using a rotary viscometer, but when a thermosetting resin is blended in the components of the hot-melt adhesive, the measured value in the model formulation without the curing agent is Used. If the curing reaction rate exceeds 20%, the curing reaction proceeds too much, and if the chip is defective, the chip cannot be peeled off. When the melt viscosity exceeds 5000 poise, the adhesive is not removed from between the connection electrodes during the temporary curing connection, and the electrical connection between the conductive particles and the connection electrodes (generally, the connection resistance of 20Ω or less) cannot be obtained, and The problem arises that inspection is not possible.

According to the present invention, a connecting member containing conductive particles and at least a phenoxy resin, an epoxy resin, and a latent curing agent is used, and the curing reaction rate of the connecting member is 20% or less and the melt viscosity is 5000 poise or less. Since the temporary curing connection is performed at a temperature, the chip inspection at the time of the temporary curing connection can be easily performed, and the chip can be replaced when the chip is defective, so that an expensive liquid crystal panel can be reused, which reduces the manufacturing cost of the liquid crystal display panel. It can be greatly reduced.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an IC chip mounting method and a connecting member according to the present invention will be specifically described below with reference to << Example 1 >> to << Example 4 >> and << Comparative Example 1 >> to << Comparative Example. 3 >>.

Example 1 35 parts of a phenoxy resin (high molecular weight epoxy) and 65 parts of a liquid epoxy (epoxy equivalent 185) containing a microcapsule type latent curing agent were dissolved in ethyl acetate to obtain a 30% solution. . In this solution, 5 vol% of conductive particles having an Au layer formed on the surface of a polystyrene core (diameter: 5 μm) were dispersed. This dispersion is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater,
It was dried at 100 ° C. for 10 minutes to prepare a connection member 1 having a thickness of 25 μm. The curing reaction rate of this adhesive measured by DSC is
The melt viscosity at 120 ° C. of the model formulation obtained by removing the curing agent from the adhesive was 4% by heating at 120 ° C. for 2 seconds, and was 300 poise.

Next, using the connection member 1 thus produced, a chip (2 mm × 10 mm) with a gold bump (area: 70 μm × 70 μm, height: 15 μm) and a glass substrate with an ITO electrode are preliminarily cured as shown below. went. This anisotropic conductive film (3 mm width) is applied to a glass substrate with an ITO electrode at 80 ° C,
After sticking at 10 kgf / cm ² , the separator was peeled off, and the bump of the chip and the ITO electrode were aligned. Next, heating and pressurization were performed from above the chip for 2 seconds at 120 ° C. and a pressure of 30 g / bump, and temporary curing connection was performed. The connection resistance after temporary curing connection is 1.3 per bump.
It was Ω, and had sufficient conduction to allow the inspection of the chip. The defective chip could be easily removed. Table 1 shows the characteristics of the connection member 1 at the temporary curing connection temperature (connection time: 2S). From Table 1, it can be seen that the provisional curing connection property that enables the inspection and replacement of the chip is excellent by performing the provisional curing connection under the condition that the curing reaction rate of the connecting member is 20% or less and the melt viscosity is 5000 poise or less. Recognize.

[0022]

[Table 1]

After chip inspection by temporary curing connection, 170
The main connection was performed by heating and pressurizing from above the chip under the conditions of ° C, 50 g / bump, and 20 seconds. The connection resistance after this connection is 0.6Ω per bump, 0.2Ω on average,
Insulation resistance is more than 10 ⁸ and these values are 85 ℃ / 8
There was almost no change even after 1000% RH treatment for 5 hours, showing good connection reliability.

Example 2 45 parts of a phenoxy resin (high molecular weight epoxy) and 55 parts of a liquid epoxy (epoxy equivalent 185) containing a microcapsule type latent curing agent were dissolved in ethyl acetate to obtain a 30% solution. . In this solution, 5 vol% of conductive particles having an Au layer formed on the surface of a polystyrene core (diameter: 5 μm) were dispersed. This dispersion is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater,
It was dried at 100 ° C. for 10 minutes to prepare a connection member 2 having a thickness of 25 μm. The curing reaction rate of this adhesive measured by DSC is
The melt viscosity at 120 ° C. of the model formulation obtained by removing the curing agent from the adhesive was 4% by heating at 120 ° C. for 2 seconds, and was 1000 poise.

Next, using the connection member 2 produced as described above, the temporary curing connection of the chip (2 mm × 10 mm) with the gold bump (area: 70 μm × 70 μm, height: 15 μm) and the glass substrate with the ITO electrode is performed as shown below. went. This anisotropic conductive film (3 mm width) is applied to a glass substrate with an ITO electrode at 80 ° C,
After sticking at 10 kgf / cm ² , the separator was peeled off, and the bump of the chip and the electrode of ITO were aligned. Next, heating and pressurization were performed from above the chip for 2 seconds at 120 ° C. and a pressure of 30 g / bump, and temporary curing connection was performed. The connection resistance after the temporary curing connection was 3Ω per bump, and the connection resistance was sufficient to inspect the chip. The defective chip could be easily removed. Table 2 shows the temporary curing connection temperature of this connection member 2 (connection time: 2
The characteristics in S) are shown. From Table 2, it can be seen that the provisional curing connection property that enables the inspection and replacement of the chip is excellent by performing the provisional curing connection under the condition that the curing reaction rate of the connecting member is 20% or less and the melt viscosity is 5000 poise or less. Recognize.

[0026]

[Table 2]

After chip inspection by temporary curing connection, 170
The main connection was performed by heating and pressurizing from above the chip under the conditions of ° C, 50 g / bump, and 20 seconds. The maximum connection resistance after this connection is 0.9Ω per bump, 0.4Ω on average,
Insulation resistance is 10 ⁸ Ω or more, these values are 85 ℃ /
Even after the treatment of 85% RH for 1000 hours, there was almost no change and good connection reliability was shown.

Example 3 60 parts of a phenoxy resin (high molecular weight epoxy) and 40 parts of a liquid epoxy (epoxy equivalent 185) containing a microcapsule type latent curing agent were dissolved in ethyl acetate to obtain a 30% solution. . In this solution, 5 vol% of conductive particles having an Au layer formed on the surface of a polystyrene core (diameter: 5 μm) were dispersed. This dispersion is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater,
The connection member 3 having a thickness of 25 μm was manufactured by drying at 100 ° C. for 10 minutes. The curing reaction rate of this adhesive measured by DSC is
The melt viscosity at 145 ° C. of the model formulation in which the curing agent was removed from the adhesive was 4,000 ° C. and 14% by heating for 2 seconds at 145 ° C.

Next, using the connection member 3 thus prepared, a temporary curing connection of a chip (2 mm × 10 mm) with a gold bump (area: 70 μm × 70 μm, height: 15 μm) and a glass substrate with an ITO electrode is performed as shown below. went. This anisotropic conductive film (3 mm width) is applied to a glass substrate with an ITO electrode at 80 ° C,
After sticking at 10 kgf / cm ² , the separator was peeled off, and the bump of the chip and the electrode of ITO were aligned. Then, heating and pressurization were performed from above the chip for 2 seconds at 145 ° C. and a pressure of 30 g / bump for temporary curing connection. The connection resistance after the temporary curing connection was 3Ω per bump, and the connection resistance was sufficient to inspect the chip. The defective chip could be easily removed. Table 3 shows the temporary curing connection temperature of this connection member 3 (connection time: 2
The characteristics in S) are shown. It can be seen from Table 3 that the provisional curing connection characteristic that enables the inspection and replacement of the chip is excellent by performing the provisional curing connection under the condition that the curing reaction rate of the connecting member is 20% or less and the melt viscosity is 5000 poise or less. Recognize.

[0030]

[Table 3]

After the chip inspection by the temporary curing connection, 170
The main connection was performed by heating and pressurizing from above the chip under the conditions of ° C, 50 g / bump, and 20 seconds. The connection resistance after this connection is 1.2Ω per bump, 0.6Ω on average,
Insulation resistance is 10 ⁸ Ω or more, these values are 85 ℃ /
Even after the treatment of 85% RH for 1000 hours, there was almost no change and good connection reliability was shown.

Example 4 60 parts of a phenoxy resin (high molecular weight epoxy) and 40 parts of a liquid epoxy (epoxy equivalent 185) containing a microcapsule type latent curing agent were dissolved in ethyl acetate to obtain a 30% solution. . This dispersion was applied to a separator (polyethylene terephthalate film treated with silicone, thickness 40 μm) with a roll coater, dried at 100 ° C. for 10 minutes, and film 1 having a thickness of 15 μm was applied.
Was prepared. Then, 35 parts of a phenoxy resin and 65 parts of a liquid epoxy (epoxy equivalent 185) containing a microcapsule type latent curing agent are dissolved in ethyl acetate to give 30%.
A solution was obtained. Polystyrene-based nuclide (diameter: 5
5% by volume of conductive particles having an Au layer formed on the surface of
Dispersed. This dispersion is used as a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm
m) was coated with a roll coater and dried at 100 ° C. for 10 minutes to prepare a film 2 having a thickness of 10 μm. The produced films 1 and 2 were laminated to produce a connecting member 4. The curing reaction rate of this connecting member 4 measured by DSC is 145.
The melt viscosity at 145 ° C. of the model formulation obtained by removing the curing agent from the connecting member 4 was 2800 poise at 13 ° C. by heating at 2 ° C. for 2 seconds.

Next, using the connection member 4 thus produced, a temporary curing connection of a chip (2 mm × 10 mm) with a gold bump (area: 70 μm × 70 μm, height: 15 μm) and a glass substrate with an ITO electrode is performed as shown below. went. This anisotropic conductive film (3 mm width) is applied to a glass substrate with an ITO electrode at 80 ° C,
After sticking at 10 kgf / cm ² , the separator was peeled off, and the bump of the chip and the electrode of ITO were aligned. Then, heating and pressurization were performed from above the chip for 2 seconds at 145 ° C. and a pressure of 30 g / bump for temporary curing connection. The connection resistance after temporary curing connection is 2.1 per bump.
Ω, and there was sufficient conduction so that the chip could be inspected even after 4 days. The defective chip could be easily removed.

After chip inspection by temporary curing connection, 170
The main connection was performed by heating and pressurizing from above the chip under the conditions of ° C, 50 g / bump, and 20 seconds. The connection resistance after this connection is 1.2Ω per bump, 0.6Ω on average,
Insulation resistance is 10 ⁸ Ω or more, these values are 85 ℃ /
Even after the treatment of 85% RH for 1000 hours, there was almost no change and good connection reliability was shown.

Comparative Example 1 A connecting member 3 having a thickness of 25 μm was produced in the same manner as in Example 3. DSC of this adhesive
The curing reaction rate measured by 4 is 4 by heating at 120 ° C for 2 seconds.
%, 120 ° C of model formulation with the curing agent removed from the adhesive
Had a melt viscosity of 9000 poise.

Then, the connection member 3 produced was heated and pressed from above the chip for 2 seconds at 120 ° C. and a pressure of 30 g / bump in the same manner as in Examples 1 and 2 to perform temporary curing connection. The connection resistance after the temporary curing connection could not be inspected for the chip due to poor conduction.

Comparative Example 2 A connecting member 3 having a thickness of 25 μm was produced in the same manner as in Example 3. The curing reaction rate measured by this adhesive DSC was 34 ° C when heated at 160 ° C for 2 seconds.
%, 160 ° C of model formulation with curing agent removed from adhesive
Had a melt viscosity of 1000 poise.

Next, the connecting member 3 produced was heated at 160 ° C. for 30 minutes.
Heating and pressurization were performed for 2 seconds from above the chip with a pressure of g / bump to perform temporary curing connection. The connection resistance after the temporary curing connection was 2.7Ω per bump, and the connection had sufficient conduction for chip inspection. However, it is difficult to remove the defective chip and the chip cannot be replaced.

Comparative Example 3 A microcapsule type latent curing agent is contained in the same manner as in Example 1 except that a liquid epoxy resin of bisphenol A type is blended instead of blending the phenoxy resin in Example 1. A liquid epoxy (epoxy equivalent 185) was dissolved in ethyl acetate to obtain a 40% solution, and 5 vol% of conductive particles having an Au layer formed on the surface of a polystyrene nucleus (diameter: 5 μm) were dispersed in this solution.
A paste-like connecting member 1 was produced. D of this connecting member
The curing reaction rate measured by SC is 3% by heating at 120 ° C. for 2 seconds, and 12% of the model composition in which the curing agent is removed from the adhesive.
The melt viscosity at 0 ° C. was 100 poise.

Next, the connection member 1 produced was heated and pressed for 2 seconds from above the chip at 120 ° C. and a pressure of 30 g / bump in the same manner as in Example 1 to perform temporary curing connection. The connection resistance after the temporary curing connection was 1.2Ω, but the chip could not be inspected due to poor conduction after 4 hours.

[0041]

As described above, the method of the present invention and the connecting member used in the method have a curing reaction rate of the hot-melt adhesive of 20% or less and a melt viscosity of 50 in the connecting member.
Since it is set to 00 poises or less, it is easy to establish an electrical conduction state when inspecting the chip in the temporary curing connection state, the IC chip can be easily inspected, and the IC chip can be easily replaced. You can do it.

Therefore, since the inspection and replacement of the IC chip can be carried out smoothly, the liquid crystal panel can be reused, and the manufacturing cost of the liquid crystal display panel can be greatly reduced.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Watanabe 1500 Ogawa, Shimodate, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Research Laboratory (72) Inventor Kazura Kojima 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Research Laboratory (72) Inventor Kyokuhisa Ota 1500 Ogawa, Shimodate City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Research Laboratory

Claims (2)

[Claims] 1. A conductive particle and a heat-meltable adhesive,
After the connection by heating and pressurization, the IC chip is provisionally cured and connected to the substrate by using a connecting member having conductivity in the pressurizing direction.
In a method of mounting an IC chip, wherein after inspecting a C chip, the IC chip is permanently connected to a substrate at a curing temperature of the hot-melt adhesive, the connecting member contains at least a phenoxy resin, an epoxy resin, and a latent curing agent. Then, the mounting method of the IC chip is characterized in that the curing reaction rate of the connection member is 20% or less and the melt viscosity is provisionally cured at a temperature of 5000 poise or less. 2. A conductive particle and a heat-meltable adhesive,
After connection by heating and pressurization, in a connection member having conductivity in the pressurizing direction, the connection member contains at least a phenoxy resin, an epoxy resin and a latent curing agent, and the curing reaction rate at the temporary curing connection temperature is 20. % And a melt viscosity of 5000 poise or less, a connecting member.