JP2008085287A - Method for connecting circuit member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection method capable of sufficiently suppressing overheat of a semiconductor chip in the case of connecting the semiconductor chip to a circuit board by heating a connection member arranged between the semiconductor chip and the circuit board. <P>SOLUTION: In the connection method of the circuit board, the connection member 30 composed of an adhesive composition is arranged between the circuit board 10 and the semiconductor chip 20 which are opposed to each other, the connection member 30 is heated to stick the semiconductor chip 20 to the circuit board 10 and to electrically connect both electrodes of the circuit board 10 and the semiconductor chip 20. The circuit board 10 is provided with a heating circuit 8a arranged on a portion on which the connection member 30 is arranged and the heating processing is performed by supplying a current to the heating circuit 8a and heating the connection member 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for connecting circuit members.

  As a method for connecting circuit members such as a connection between a semiconductor element or a liquid crystal display element and a circuit board, a method using a connection member made of a heat-adhesive adhesive containing a thermosetting resin or a thermoplastic resin is known. Yes. For example, Patent Document 1 describes that a connection member made of a thermosetting resin is used for connection between a semiconductor element and a wiring board. Patent Document 2 describes that an anisotropic conductive material is used as a connection member for connection between wiring boards. The anisotropic conductive material of Patent Document 2 is obtained by dispersing conductive particles such as metal powder and metal oxide in an adhesive component mainly composed of a thermoplastic resin.

  The connecting member may be used by a method in which the connecting member is directly applied onto a circuit member to be connected and dried to form a film, or supplied in the form of a film formed on a carrier film such as polyethylene terephthalate. In some cases. In any case, the connecting member is interposed between the circuit members to be connected, and the connecting member is heated while being pressed in this state. Thereby, while maintaining the insulation between the electrodes which adjoin in the same circuit member, the electrodes which oppose are electrically connected, and circuit members are adhesively fixed simultaneously.

When the adhesive component is a thermosetting resin, the connection member is cured by the heat treatment and the circuit members are connected to each other. On the other hand, when the adhesive component is a thermoplastic resin, the circuit members are connected by pressure bonding in a state where the connection member is softened by the heat treatment.
JP 60-262430 A Japanese Patent Laid-Open No. 55-104007

  As described above, in the step of connecting the circuit members, heat treatment is performed to cure or soften the connection member. Conventionally, an external heating means such as an oven or a hot press is used as a method for heating the connecting member. When these external heating means are used, not only the connection member to be heat-treated but also the circuit member is heated. Therefore, when a semiconductor chip incorporating a special circuit such as an optical sensor with low heat resistance is connected to a circuit board, the semiconductor chip may malfunction.

  For example, when a hot press is used in the connection process, a semiconductor chip is placed on a circuit board via a connection member at a predetermined position, and a pressure head incorporating an electric heater is pressed from above the semiconductor chip. A heating method is generally employed. In this case, the thermal energy from the pressure head is transmitted to the connection member via the semiconductor chip. In order to sufficiently heat the connection member, it is necessary to set the surface temperature of the pressure head to a temperature higher than the temperature required for the heat treatment of the connection member. If it does so, a semiconductor chip will be overheated by being pressed with a high temperature pressurization head, and the possibility of causing the malfunction problem mentioned above becomes higher.

  The present invention has been made in view of the above circumstances, and when a connecting member disposed between a semiconductor chip and a circuit board is heat-treated to connect the semiconductor chip and the circuit board, the semiconductor chip is sufficiently heated. It is an object to provide a connection method that can be suppressed.

  In the method for connecting circuit members according to the present invention, a connection member made of an adhesive composition is interposed between a circuit board and a semiconductor chip arranged to face each other, and the connection member is subjected to a heat treatment to connect the circuit board and the semiconductor chip. The circuit board and the semiconductor chip are electrically connected to each other and bonded to each other, and the circuit board includes a heating circuit in a region where the connection member is disposed on a surface facing the connection member. The heat treatment is performed by energizing the heating circuit to generate heat.

  According to the present invention, since the connection member and the heating circuit are in contact, the heat energy required for the heat treatment can be directly supplied from the heating circuit to the connection member. Therefore, excessive heat energy does not flow into the semiconductor chip as compared with the case where the connecting member is heat-treated through the semiconductor chip as in the case of using a hot press. Therefore, the connection member can be sufficiently heat-treated while sufficiently suppressing the temperature rise of the semiconductor chip. Therefore, even if the semiconductor chip has low heat resistance, it is possible to sufficiently suppress the occurrence of malfunction due to heat.

  The heat treatment in the present invention is preferably performed while pressurizing the whole in a direction in which the circuit board and the semiconductor chip are pressed against each other. When the heat treatment is performed while applying pressure, the connection reliability between the two electrodes can be made higher.

  Further, according to the present invention, in addition to the above-mentioned problem of malfunction due to heat of the semiconductor chip, the following problems of connection processing by conventional heat press can be sufficiently solved. That is, when the connection process between the circuit board and the semiconductor chip is repeatedly performed using a heat press, the heating by the electric heater is repeated, so that the pressure head is distorted due to thermal expansion. In the connection process between the electrodes using the connection member, the parallelism of the pressure head is extremely important for obtaining good connection reliability. For this reason, it is necessary to adjust the parallelism of the pressure head every certain time, and this adjustment causes a reduction in work efficiency.

  On the other hand, since the heat treatment in the present invention is performed by a heating circuit, a press having a pressure head that does not incorporate an electric heater can be used. Or even if it incorporates an electric heater, it is not necessary to use the electric heater. Therefore, distortion and deterioration of the pressure head due to thermal expansion can be sufficiently suppressed. As a result, the number of adjustments of the parallelism of the pressure head can be reduced, and work efficiency can be improved.

  The circuit board according to the present invention is provided with a circuit pattern on the surface facing the connecting member, and this circuit pattern is arranged such that the electrode connected to the electrode of the semiconductor chip and the heating circuit are electrically insulated from each other. It is preferable to be provided. When the heating circuit and the electrode are electrically insulated, it is possible to sufficiently prevent an electrical influence on the semiconductor chip to which the heating circuit that has been used for the heat treatment and has finished its role is connected.

  The sheet resistance value of the portion in contact with the connection member of the heating circuit is preferably 2 to 150Ω / □ from the viewpoint of efficiently obtaining the heat generation amount necessary for the heat treatment of the circuit member. Further, the heating circuit can have a single-layer structure including a single conductive layer or a stacked structure in which two or more conductive layers are stacked. When the heating circuit has a single-layer structure, the heating circuit can be formed of a conductive layer selected from the group consisting of a metal thin film, an indium-tin oxide layer, an indium-zinc oxide layer, and a tin oxide layer. When the heating circuit has a laminated structure, the heating circuit can be composed of two or more conductive layers selected independently from each other from the group of conductive layers.

  As the connecting member, it is preferable to use a member formed by forming an anisotropic conductive adhesive composition comprising an adhesive component and conductive particles dispersed in the adhesive component into a film shape. Thereby, both the low connection resistance between the opposing electrodes and the excellent insulation between the adjacent electrodes can be achieved at a higher level.

  The adhesive component preferably contains a film forming material, an epoxy resin, and a latent curing agent. When the connecting member contains these as an adhesive component, it is easy to process the connecting member into a film, and the circuit board and the semiconductor chip can be easily connected by curing the connecting member by heating.

  According to the present invention, there is provided a connection method capable of sufficiently suppressing overheating of a semiconductor chip when the connection member disposed between the semiconductor chip and the circuit board is heated to connect the semiconductor chip and the circuit board. Can do.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. For the convenience of the drawings, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a top view showing an example of a circuit board used in the present embodiment. A circuit board 10 shown in FIG. 1 includes a rectangular glass substrate 1 and a circuit pattern formed on the surface of the glass substrate 1. This circuit pattern is composed of electrode portions 3 and 4 respectively connected to the electrode portions of the semiconductor chip, and a heating circuit 8 used when the connection member is heated.

  As shown in FIG. 1, the electrode part 3 is comprised by the some electrode 3a, and the some electrode 3a is formed so that it may become substantially equal intervals at the edge part of the one side of the glass substrate 1, respectively. Each electrode 3 a is formed in the direction of the side 14 facing the side 13 with the edge of the side 13 of the glass substrate 1 as the base end, and extends to the front of the central portion of the glass substrate 1. Similarly, the electrode part 4 is comprised by the some electrode 4a, and the some electrode 4a is formed so that it may become substantially equal intervals at the edge part of the edge | side 14 of the glass substrate 1, respectively. Each electrode 4 a is formed in the direction of the side 13 with the edge of the side 14 of the glass substrate 1 as the base end, and extends to the front of the central portion of the glass substrate 1.

  The heating circuit 8 includes a rectangular heating unit 8a formed in the central portion of the glass substrate 1 and a current supply unit 8b connected to the heating unit 8a and supplying current to the heating unit 8a. A semiconductor chip is arranged through a circuit member in a portion where the heating portion 8a is formed. In the state where the semiconductor chip is arranged, the front end side of the current supply unit 8b extends to the edge of the side 14 of the glass substrate 1 so that the power supply terminal can be connected to the circuit board 10 and current can be supplied to the heating unit 8a. It is extended.

  The heating circuit 8 is formed separately from the electrodes 3a and 4a, and these are electrically independent from each other. From the viewpoint of sufficiently uniformly heating the connecting member disposed on the heating portion 8a, it is desirable that the heating portion 8a of the heating circuit 8 be formed in a region avoiding the electrode portions 3 and 4 with as wide an area as possible.

  The heating circuit 8 can be formed of a metal thin film or a layer made of indium tin oxide (ITO), indium zinc oxide (IZO), or tin oxide. Of the above materials that can constitute the heating circuit 8, ITO or IZO is preferable from the viewpoint that the appearance of connection can be easily inspected using an optical microscope after the connection process. The heating circuit 8 may have a single layer structure made of one kind of the above materials or a laminated structure in which two or more layers made of different materials are laminated.

  The thickness of the heating circuit 8 is preferably sufficiently thin. If the heating circuit 8 is sufficiently thin, it can be easily formed on the glass substrate 1 by a film forming method such as sputtering, and even if it exists in the connection structure, it is spatial in the structure of the connection portion. There is an advantage that there is no restriction.

  The sheet resistance value of the heating part 8a of the heating circuit 8 is 2 to 150Ω / □ from the viewpoint of efficiently obtaining the heat generation amount necessary for the heat treatment of the connection member, although it depends on the type of the connection member used. Is preferred. If the sheet resistance value is less than 2Ω / □, a high current must be applied in order to obtain a sufficient calorific value, and there is a tendency that the design of the power supply device is restricted. On the other hand, if the sheet resistance value exceeds 150Ω / □, a sufficient amount of heat cannot be obtained unless a high voltage is applied, and a special power supply device corresponding to the high voltage tends to be required. Here, the sheet resistance value is a value measured by a surface resistance measuring instrument using a four-probe method.

  The electrodes 3a, 4a and the heating circuit 8 formed on the surface of the glass substrate 1 are each preferably formed by a film forming method such as sputtering from the viewpoint of workability. When the electrodes 3a and 4a and the heating circuit 8 are made of the same material, after the film is formed on the entire surface of the one side of the glass substrate 1, unnecessary portions are deleted by etching or the like to remove circuit patterns (electrode portions 3, 3). 4 and heating circuit 8) may be formed.

  FIG. 2 is a schematic cross-sectional view showing a connection structure in which the above-described circuit board 10 and a semiconductor chip are connected. A connection structure 100 shown in FIG. 2 includes a circuit board 10 and a semiconductor chip 20 that are arranged to face each other, and a connection portion 30b that connects them is provided between the circuit board 10 and the semiconductor chip 20. .

  The semiconductor chip 20 includes a plurality of electrodes 5 a and 6 a connected to the electrodes of the electrode portions 3 and 4 of the circuit board 10 on the surface facing the circuit board 10. Specific examples of the semiconductor chip 20 include components such as an IC chip, a resistor chip, and a capacitor chip. These chip parts are generally provided with a large number of electrodes.

  The surfaces of the plurality of electrodes of the semiconductor chip 20 may be composed of one or more selected from gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum and ITO. May be. Moreover, the material of the surface of an electrode may be the same in all the electrodes, and may differ.

  As shown in FIG. 2, the connection portion 30 b includes a cured product 32 b of an adhesive component contained in the connection member, and conductive particles 35 dispersed therein. In the connection structure 100, the electrode 3a of the circuit board 10 and the electrode 5a of the semiconductor chip 20 are electrically connected via the conductive particles 35, and the electrode 4a of the circuit board 10 and the electrode 6a of the semiconductor chip 20 are electrically connected via the conductive particles 35. Are connected to each. For this reason, the connection resistance between the electrodes 3a and 5a and between the electrodes 4a and 6a is sufficiently reduced, and a good electrical connection between the circuit board 10 and the semiconductor chip 20 becomes possible. On the other hand, the cured product 32b has electrical insulation, and insulation between adjacent electrodes is ensured. Therefore, the functions of the semiconductor chip 20 can be sufficiently exhibited.

  Next, the connection member in a state before the adhesive component is cured will be described. As the connecting member, an anisotropic conductive adhesive composition comprising a thermosetting resin, an adhesive component containing a curing agent, and conductive particles dispersed in the adhesive component is formed into a film ( Hereinafter, it is referred to as “anisotropic conductive film”).

  In addition, if an adhesive component is what can adhere | attach circuit members by heating (heat-adhesive adhesive), the containing component will not be limited. For example, a thermoplastic resin such as polyethylene or polypropylene may be used as the resin material that forms the main component of the adhesive component. However, curable resins such as epoxy resins, polyimide resins, polyamideimide resins, and acrylic resins are preferable from the viewpoints of heat resistance, moisture resistance, and mechanical properties.

  Although it will not specifically limit as a thermosetting resin if it is a thermosetting resin which can be hardened in arbitrary temperature ranges, It is preferable that it is an epoxy resin. Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, fat Examples thereof include cyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated. These epoxy resins can be used individually by 1 type or in combination of 2 or more types.

  Examples of the curing agent for thermosetting resins include amines, phenols, acid anhydrides, imidazoles, hydrazides, dicyandiamide, boron trifluoride-amine complexes, sulfonium salts, iodonium salts, and amine imides. These can be used alone or in admixture of two or more, and may be used by mixing a decomposition accelerator, an inhibitor and the like. In addition, those obtained by coating these curing agents with a polyurethane-based or polyester-based polymer substance and making them into microcapsules (latent curing agents) are preferable because the pot life is extended.

  The adhesive component may contain a film-forming polymer (film-forming material). Based on the total mass of the adhesive component, the content of the film-forming polymer is preferably 2 to 80% by mass, more preferably 5 to 70% by mass, and 10 to 60% by mass. More preferably. As the film-forming polymer, polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene oxide, urea resin, melamine resin, phenol resin, xylene resin, polyisocyanate resin, phenoxy resin, A polyimide resin, a polyester urethane resin, or the like is used. It is preferable to include a film-forming polymer in the adhesive component because the anisotropic conductive adhesive composition can be easily processed into a film.

  Among the above film-forming polymers, a resin having a functional group such as a hydroxyl group is more preferable because the adhesion can be improved. Also, those obtained by modifying these polymers with radically polymerizable functional groups can be used.

  Further, the adhesive component is a curing agent that generates free radicals upon heating, a radical polymerizable substance, a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, and a coupling agent. , Phenol resin, melamine resin, isocyanates and the like can also be contained.

  Examples of the conductive particles dispersed in the adhesive component include metal particles such as gold, silver, copper, nickel, and solder, and carbon particles. Alternatively, coated particles in which non-conductive glass, ceramic, plastic, or the like is used as a core and the core is coated with the above metal or carbon may be used. The average particle diameter of the conductive particles is preferably 1 to 18 μm from the viewpoints of dispersibility and conductivity.

  The blending ratio of the conductive particles is preferably 0.1 to 30 parts by volume, and more preferably 0.1 to 10 parts by volume with respect to 100 parts by volume of the adhesive component. If the blending ratio is less than 0.1 part by volume, the connection resistance between the opposing electrodes tends to be high, and if it exceeds 30 parts by volume, a short circuit between adjacent electrodes tends to occur.

  As the connecting member, a commercially available anisotropic conductive film may be purchased and used. For example, AC-8955YW-23 (trade name, manufactured by Hitachi Chemical Co., Ltd., trade name) can be suitably used.

(Connection method)
FIG. 3A to FIG. 3C are process diagrams showing an embodiment of a circuit member connection method according to the present invention in schematic cross-sectional views. In the present embodiment, the connection member 100 is thermally cured by energizing the heating circuit 8 of the circuit board 10 to manufacture the connection structure 100.

  First, the circuit board 10 provided with the electrode parts 3 and 4 and the heating circuit 8 on one surface, the semiconductor chip 20, and the anisotropic conductive film (connecting member) 30 are prepared. The anisotropic conductive film 30 is composed of an adhesive component 32 and conductive particles 35 dispersed in the adhesive component 32. The thickness of the anisotropic conductive film 30 is preferably 5 to 50 μm. When the thickness of the anisotropic conductive film 30 is less than 5 μm, the filling amount tends to be insufficient between the electrodes to be connected. On the other hand, when it exceeds 50 μm, it tends to be difficult to ensure conduction between the electrodes to be connected.

  Next, the circuit board 10 is placed on the bottom surface 50 of the press with the surface on which the circuit pattern is formed facing up. Thereafter, as shown in FIG. 3A, the anisotropic conductive film 30 is placed at a position where the heating portion 8a of the circuit board 10 is formed. At this time, the anisotropic conductive film 30 is placed so as to cover the heating portion 8a of the heating circuit 8 and the tips of the electrodes 3a and 4a.

  Next, the electrodes 5a and 6a of the semiconductor chip 20 are aligned so that they are opposed to the electrodes 3a and 4a of the circuit board 10, respectively, and anisotropically conductive as shown in FIG. The semiconductor chip 20 is placed on the circuit board 10 via the film 30. Then, as shown in FIG. 3C, the pressure head of the press is pressed from above the semiconductor chip 20. At this time, the entire surface is pressurized in the directions of arrows A and B in FIG. 3C by the contact surface 55 and the bottom surface 50 of the pressure head, and current is supplied to the heating circuit 8 to cause the heating unit 8a to generate heat. Then, the anisotropic conductive film 30 is heat-treated.

  The heating temperature at this time is set to a temperature at which the anisotropic conductive film 30 can be cured. The heating temperature is preferably 60 to 180 ° C, more preferably 70 to 170 ° C, and still more preferably 80 to 160 ° C. If the heating temperature is less than 60 ° C, the curing rate tends to be slow, and if it exceeds 180 ° C, unwanted side reactions tend to proceed. The heating time is preferably 0.1 to 180 seconds, more preferably 0.5 to 180 seconds, and still more preferably 1 to 180 seconds.

  The connection part 30b is formed by hardening of the anisotropic conductive film 30, and the connection structure 100 as shown in FIG. 2 is obtained. The connection conditions are appropriately selected depending on the application to be used, the adhesive composition, and the circuit member. In addition, what is necessary is just to irradiate actinic light and an energy ray suitably to the anisotropic conductive film 30, when the adhesive agent component of the anisotropic conductive film 30 contains what hardens | cures with light. Examples of the active light include ultraviolet light, visible light, and infrared light. Examples of energy rays include electron beams, X-rays, γ rays, and microwaves.

  According to the connection method according to the present embodiment, the anisotropic conductive film 30 can be directly heated by the heating unit 8a of the heating circuit 8 located immediately below the anisotropic conductive film 30. Thereby, there are the following advantages compared with the conventional connection method using the electric heater of the pressure head as a heat source. That is, since the anisotropic conductive film 30 can be heated intensively, the thermal energy flowing into the semiconductor chip 20 can be reduced. As a result, even if the semiconductor chip 20 has low heat resistance, it is possible to sufficiently suppress the occurrence of malfunction due to heat. Further, since it is not necessary to use an electric heater built in the pressure head, it is possible to sufficiently prevent distortion of the pressure head due to thermal expansion and deterioration of the pressure head due to heating. As a result, the number of operations such as adjusting the parallelism of the pressure head can be reduced, and the workability of the connection process can be improved.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof. For example, the anisotropic conductive film is not limited to a single layer structure, and may have a multilayer structure in which a plurality of layers are laminated. An anisotropic conductive film having a multilayer structure can be produced, for example, by laminating a plurality of layers having different types of adhesive components and conductive particles or different contents thereof.

  Moreover, in the said embodiment, although the anisotropic conductive film containing a conductive particle was illustrated as a connection member, what contains a conductive particle does not necessarily need to be used. However, in order to connect the electrodes with higher connection reliability, it is preferable to use those containing conductive particles. This is because, when conductive particles are used, the electrodes can be more reliably connected to each other even if there is some variation in height between the electrodes of the semiconductor chip or the electrodes of the circuit board.

  Furthermore, in the said embodiment, although the thing formed in the film form was used as a connection member, even if it forms a connection member by drying this after apply | coating an adhesive composition directly on a circuit board. Good. In this case, the applied adhesive composition may be dried by energizing the heating circuit 8 to generate heat. Moreover, although what used the glass substrate as a circuit board was illustrated, what formed the circuit pattern on the surface of the board | substrate which consists of various resin materials may be used.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these.

(Example 1)
On the surface of a glass substrate having a width of 20 mm, a length of 30 mm, and a thickness of 0.7 mm, a large number of transparent electrodes that form electrical contacts with the electrodes of the semiconductor chip were formed. The transparent electrode is made of an ITO thin film, and a total of 480 transparent electrodes having a width of 25 μm and a thickness of 150 nm are formed on a glass substrate.

  Further, a heating circuit made of an ITO thin film was further formed on the same surface as the surface on which the transparent electrode of the glass substrate was formed. Such a heating circuit is formed by depositing an ITO thin film (thickness 150 nm) on a glass substrate by sputtering using an ITO target, and then patterning by wet etching so as not to have an electrical contact with the transparent electrode. Produced. Specifically, the heating circuit includes a heating part formed in a portion of the glass substrate that contacts the semiconductor chip and two current supply parts formed to supply current to the heating part from the outside. ing. The heating part was formed in a rectangular shape having a width of 3.5 mm and a length of 20 mm so as to be approximately 70% of the area where the semiconductor chip abuts. Moreover, the two current supply parts were formed so that the front-end | tip part extended to the peripheral part of a glass substrate. In addition, when the sheet resistance value of the heating part of the heating circuit was measured by the four probe method, it was 10Ω / □.

  The glass substrate is placed in a press so that the side on which the transparent electrode and the heating circuit are formed is the upper surface, and an epoxy resin anisotropic conductive film (width: 15 mm, length: 15 mm) on the press machine (manufactured by Hitachi Chemical Co., Ltd.) , Trade name: AC-8955YW-23). Thereafter, a test semiconductor chip (width 4.0 mm, length 14 mm, thickness 550 μm) is placed on the anisotropic conductive film so that the transparent electrode on the glass substrate and the electrode on the semiconductor chip are aligned with each other at room temperature (25 ° C. ).

  By applying current to the heating circuit while pressing the whole body in the vertical direction using a press machine, the laminated body in which the anisotropic conductive film and the semiconductor chip are placed in this order on the glass substrate is used. The directionally conductive film was heat-treated. Pressurization with the pressure head was performed at a pressure of 3 MPa (based on the area of the semiconductor chip). The energization of the heating circuit was performed by applying a current of 300 mA for 15 seconds through the current supply unit of the heating circuit. The anisotropic conductive film was thermally cured by such heat treatment to obtain a connection structure composed of a cured product of the semiconductor chip, the glass substrate, and the connection member disposed therebetween.

  Prior to the connection process, a thermocouple (Rika Kogyo Co., Ltd., trade name: ST-50) was inserted into the anisotropic conductive film, and the temperature of the anisotropic conductive film during the connection process was measured. . As a result, the temperature of the anisotropic conductive film 15 seconds after the start of the heat treatment was 208 ° C. On the other hand, the temperature of the semiconductor chip during the connection process was measured using a radiation thermometer (manufactured by Keyence Corporation). As a result, the temperature of the semiconductor chip 15 seconds after the start of the heat treatment was 123 ° C.

  The connection structure obtained by the connection treatment was left in a constant temperature and humidity chamber having a temperature of 85 ° C. and a relative humidity of 85% for 500 hours. Then, the connection resistance value of the connection part of the electrode of a semiconductor chip and the transparent electrode on a glass substrate was measured by the 4-terminal method. As a result, the rate of increase was less than 10% compared with the connection resistance value measured before the treatment in the thermostatic chamber, and it was confirmed that the connection reliability was good.

(Example 2)
A connection structure was prepared and evaluated in the same manner as in Example 1 except that a heating circuit consisting of an IZO thin film (thickness 150 nm) was formed instead of the heating circuit consisting of an ITO thin film. The sheet resistance value of the heating part of the heating circuit was 15Ω / □. The temperature of the anisotropic conductive film 15 seconds after the start of the heat treatment was 198 ° C. On the other hand, the temperature of the semiconductor chip 15 seconds after the start of the heat treatment was 113 ° C. The connection resistance value of the connection part after treatment (after standing for 500 hours) in a constant temperature and humidity chamber (temperature 85 ° C., relative humidity 85%) is compared with the connection resistance value measured before the treatment. The increase rate was less than 10%, and it was confirmed that the connection reliability was good.

(Example 3)
Using the pressurizing process by the press machine and the heating process by the heating circuit, the operation for producing the connection structure was continuously performed 1000 times in the same manner as in Example 1. The 1000 connected structures prepared were arranged in a constant temperature and humidity chamber having a temperature of 85 ° C. and a relative humidity of 85%, and left for 500 hours. Then, the connection resistance value of the connection part was measured by the 4-terminal method in the same manner as in Example 1 for 1000 connection structures. As a result, compared with the connection resistance value measured before performing the treatment in the constant temperature and humidity chamber, the increase rate of the connection resistance value is less than 10% for all connection structures, and the connection reliability is good. Was confirmed.

  Furthermore, in the present example, cross-sectional observation of the connection portions of 1000 connection structures was performed. As a result, in all connection structures, the thickness of the cured anisotropic conductive film interposed between the semiconductor chip and the glass substrate is substantially equal at both ends of the connection structure, and the difference in thickness between both ends is 3 μm. Was within. From this, it was confirmed that the parallelism of the pressure head was sufficiently maintained even when the connection process 1000 times was repeated continuously.

(Comparative Example 1)
Instead of jointly using press treatment with a press and heat treatment with a heating circuit, the anisotropic conductive film was connected with a heating pressure head (surface temperature 250 ° C.) with a built-in electric heater. Except for this, the connection structure was produced and evaluated in the same manner as in Example 1. That is, a connection process was performed in which a pressure head having a surface temperature of 250 ° C. was brought into contact with the semiconductor chip from above and pressurized for 15 seconds while no current was supplied to the heating circuit on the glass substrate. In this case, the thermal energy from the pressure head is supplied to the anisotropic conductive film via the semiconductor chip.

  In this comparative example, the temperature of the anisotropic conductive film 15 seconds after the start of the connection process was 209 ° C. On the other hand, the temperature of the semiconductor chip 15 seconds after the start of the heat treatment rose to 245 ° C. In addition, the connection resistance value of the connection part after processing (after leaving for 500 hours) in a constant temperature and humidity chamber (temperature 85 ° C., relative humidity 85%) is compared with the connection resistance value measured before processing. The increase rate was less than 10%, and it was confirmed that the connection reliability was good.

(Comparative Example 2)
The anisotropic conductive film was connected by a heating type pressure head (surface temperature: 250 ° C.) with a built-in electric heater, and the connection structure was manufactured 1000 times in the same manner as in Comparative Example 1. The 1000 connected structures prepared were arranged in a constant temperature and humidity chamber having a temperature of 85 ° C. and a relative humidity of 85%, and left for 500 hours. Then, the connection resistance value of the connection part was measured by the 4-terminal method in the same manner as in Example 1 for 1000 connection structures. As a result, compared to the connection resistance value measured before performing the treatment in the thermo-hygrostat, the increase rate of the connection resistance value is less than 10% for the first 800 pieces after the start of the production of the connection structure. there were. On the other hand, for 200 pieces produced at the end of the work, there is a connection resistance value increase rate of 30 to 50%, and it is found that the connection resistance value tends to increase as the number of work repetitions increases. It was.

  Furthermore, in this comparative example, the cross-section observation of the connection part of the connection structure where the rate of increase in the connection resistance value was high was performed. As a result, the thickness of the cured anisotropic conductive film interposed between the semiconductor chip and the glass substrate had a difference of 8 μm when both ends of the connection structure were compared. The reason for the uneven thickness of the cured anisotropic conductive film is thought to be due to distortion of the pressure head due to repeated heating and cooling, resulting in insufficient parallelism, which increases connection reliability. It is inferred that it had an influence.

It is a top view which shows an example of the circuit board used in the connection method which concerns on this invention. It is a schematic cross section which shows the state with which the circuit board and the semiconductor chip were connected. It is process drawing which shows the method of connecting a circuit board and a semiconductor chip with a schematic diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Circuit board, 20 ... Semiconductor chip, 30 ... Anisotropic conductive film (connection member), 3a, 4a ... Circuit board electrode, 5a, 6a ... Semiconductor chip electrode, 8 ... Heating circuit, 32 ... Adhesive component 35 ... conductive particles, 100 ... connection structure.

Claims (8)

A connection member made of an adhesive composition is interposed between the circuit board and the semiconductor chip arranged to face each other, the connection member is heated to bond the circuit board and the semiconductor chip, and the circuit board and the semiconductor chip. A circuit member connection method for electrically connecting electrodes disposed on a semiconductor chip,
The circuit board includes a heating circuit in a region where the connection member is disposed on a surface facing the connection member, and the heating process is performed by energizing the heating circuit to generate heat.   The connection method according to claim 1, wherein the heat treatment is performed while pressing the whole in a direction in which the circuit board and the semiconductor chip are pressed against each other.   The circuit board includes a circuit pattern on a surface facing the connection member, and the circuit pattern is configured such that an electrode connected to an electrode of the semiconductor chip and the heating circuit are electrically insulated from each other. The connection method according to claim 1 or 2.   4. The connection method according to claim 1, wherein a sheet resistance value of a portion of the heating circuit that abuts on the connection member is 2 to 150Ω / □.   The heating circuit has a single-layer structure including a single conductive layer, and the conductive layer is selected from the group consisting of a metal thin film, an indium-tin oxide layer, an indium-zinc oxide layer, and a tin oxide layer. Item 5. The connection method according to any one of Items 1 to 4.   The heating circuit has a laminated structure formed by laminating two or more conductive layers, and the two or more conductive layers are independently formed of a metal thin film, an indium-tin oxide layer, an indium-zinc oxide layer. And the connection method as described in any one of Claims 1-4 chosen from the group which consists of a tin oxide layer.   The said connection member consists of an anisotropic conductive adhesive composition provided with an adhesive agent component and the electroconductive particle currently disperse | distributed in the said adhesive agent component, It is any one of Claims 1-6. The connection method described.   The connection method according to claim 7, wherein the adhesive component contains a film forming material, an epoxy resin, and a latent curing agent.

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