JP2008135704A - Manufacturing method for electronic device, and manufacturing equipment thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an electronic device that reduces warpage of a circuit board, even after surface-mounted components have been mounted on the circuit board, as well as, to provide manufacturing equipment for the electronic device. <P>SOLUTION: A circuit board and a surface-mounted component whose linear coefficient of expansion is smaller than that of the former are prepared; a crimping stage and a press-fitting head are heated up to a temporary crimping temperature; the circuit board loaded with the surface-mounted component via an anisotropic conductive material is set on the crimping stage and temporary crimping is carried out; and then the press-fitting head is heated, until it reaches the regular crimping temperature, thereby the amount of warpage of the circuit board is reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for manufacturing an electronic device by thermocompression bonding a circuit board and a mounting component.

  Thermosetting adhesives such as anisotropic conductive film (hereinafter referred to as ACF), anisotropic conductive paste (ACP), non-conductive film (NCF), etc., as a method for connecting a circuit board having many electrodes and an IC chip Is known that is thermocompression-bonded between a circuit board and an IC chip (see, for example, Patent Document 1).

  FIG. 7 is a cross-sectional view showing a conventionally known COG (Chip on Glass) mounting method. The cross-sectional view of FIG. 7 shows a method of mounting an IC chip on the glass substrate 102 by thermocompression bonding. FIG. 7A shows a state where the first electrode 101 is formed on the glass substrate 102 which is a circuit board. The first electrode 101 is an electrode for driving a liquid crystal display device (not shown), and the liquid crystal display panel portion is omitted. FIG. 7B shows a state where the adhesive 103 is placed on the first electrode 101 of the glass substrate 102. Conductive particles are dispersed inside the adhesive 103. Since the conductive particles are dispersed in the adhesive 103 which is an insulator, adjacent electrodes are insulated from each other. FIG. 7C shows a state where the IC chip 105 is mounted on the adhesive 103. In this case, the crimping stage 106 is heated to room temperature or a predetermined temperature. This heating is for improving the adhesiveness of the surface of the adhesive 103 and fixing the glass substrate 102, the adhesive 103, and the adhesive 103, and the IC chip 105 so that they do not move and are displaced. .

  A large number of second electrodes 104 are formed on the surface of the IC chip 105. When mounting the IC chip 105, the second electrode 104 of the IC chip 105 and the first electrode 101 on the glass substrate 102 are aligned so as to face each other. FIG. 7D shows a state in which the IC chip mounted on the glass substrate 102 is placed on the pressure-bonding stage 106 and the pressure-bonding head 107 is lowered and pressure-bonded. By pressurizing the crimping head 107 downward, the conductive particles dispersed in the adhesive 103 are interposed between the first electrode 101 and the second electrode 104, and between the first electrode 101 and the second electrode 104. Take electrical continuity. After pressure is applied by the pressure bonding head 107, the pressure bonding head 107 is heated. The adhesive 103 flows by heating the pressure-bonding head 107. The adhesive is then cured and then cooled. Cooling is performed in a pressurized state. Then, the pressure of the pressure bonding head 107 is released, and the glass substrate 102 is removed from the pressure bonding stage 106.

  In Patent Document 1, in particular, in order to prevent residual stress from being generated in the adhesive 103 after cooling and warping of the glass substrate or the like, the pressure state between the crimping stage 106 and the crimping head 107 is maintained. Start heating. As a result, the adhesive 103 is not heated and heated rapidly, and the residual stress of the cured adhesive can be reduced.

  FIG. 8 is an explanatory diagram for explaining the cause of warping of the glass substrate after thermocompression bonding when the glass substrate 102 and the IC chip 105 are thermocompression bonded via the adhesive 103. FIG. 8A is a schematic cross-sectional view showing a state where the glass substrate 102 and the IC chip 105 are thermocompression bonded on the pressure bonding stage 106 via the adhesive 103, and FIG. It is a graph showing the temperature distribution in the cross section. The horizontal axis represents temperature, and the vertical axis represents the cross-sectional position of the crimping stage 106 and the crimping head 107. When the graph 112 is thermocompression bonded at a low temperature, the graph 113 shows a temperature distribution when thermocompression bonding is performed at a high temperature.

  The crimping stage 106 is maintained at room temperature or a predetermined low temperature, and the crimping head 107 is maintained at the curing temperature of the adhesive 103. From the graph 112 and the graph 113, a temperature gradient is generated from the IC chip 105 to the glass substrate 102. That is, when the high-temperature pressure bonding head 107 is pressed against the IC chip 105 and pressed, the IC chip 105 rises to a temperature similar to the temperature of the pressure bonding head 107, but the glass substrate 102 has the pressure bonding head 107 and the pressure bonding stage 106. Is heated to a temperature between.

  8C is a cross-sectional view of the glass substrate 102 and the IC chip 105 during thermocompression bonding, and FIG. 8D is a cross-sectional view of the glass substrate 102 and the IC chip 105 when cooled to room temperature. At the time of crimping, the temperature of the IC chip 105 is higher than the temperature of the glass substrate 102, so that the thermal expansion of the IC chip 105 is larger than that of the glass substrate 102. However, when this is cooled, the shrinkage of the IC chip 105 is larger than the shrinkage of the glass substrate 102, so that the glass substrate 102 is concavely warped with respect to the IC chip 105. The linear thermal expansion coefficient of the silicon substrate is about 3 ppm / K, and the glass is about 4.8 ppm / K.

Such warpage becomes a problem particularly when the glass substrate 102 is a liquid crystal display panel. When the glass substrate 102 is warped, the gap of the liquid crystal layer is changed, and the display color of the changed portion is changed, or the liquid crystal display panel is uneven in color.
JP 2002-120815 A

  In the conventional example, a temperature gradient occurs between the circuit board and the mounted component during mounting, and the circuit board warps after cooling. Therefore, the present invention has been made in view of the above points, and provides an electronic device manufacturing method and an electronic device manufacturing apparatus in which warpage of a circuit board is reduced even after mounting components are mounted on the circuit board.

  In the present invention, in order to solve the above problems, the following configuration is adopted.

  (1) An anisotropic conductive material is interposed between a circuit board having a first electrode and a mounting component having a second electrode, and the first electrode and the above-mentioned electrode are heated and pressure-bonded by a pressure-bonding stage and a pressure-bonding head. In the method of manufacturing an electronic device that is electrically connected to the second electrode, the circuit board, a preparation step of preparing the mounting component having a smaller linear thermal expansion coefficient than the circuit board, and the first electrode of the circuit board Mounting the mounting component on the anisotropic conductive material, positioning the mounting component on the anisotropic conductive material, and the crimping stage and the crimping stage. The crimping head placed opposite to the heating head is heated until it reaches a temporary crimping temperature, and the circuit board is placed on the crimping stage side, and the circuit board on which the mounting component is mounted is placed on the crimping stage. A pre-attachment step, a temporary press-bonding step of moving the pressure-bonding head to temporarily press-mount the mounted component to the circuit board, and heating the pressure-bonding head until a final pressure-bonding temperature higher than the temperature of the pressure-bonding stage is reached. The pre-crimping step for placing the circuit board on the crimping stage by placing the circuit board on the crimping stage side and placing the circuit board on the crimping stage is temporarily crimped. And a final crimping step of finally crimping the mounted component to the circuit board.

(2) In the method of manufacturing an electronic device according to (1), the crimping stage and the crimping head include a first crimping stage, a first crimping head, a second crimping stage, and a second crimping head. Heating the first pressure-bonding stage and the first pressure-bonding head until reaching the pre-pressure-bonding temperature, and arranging the circuit board on the first pressure-bonding stage side to mount the circuit board on which the mounting component is mounted. The pre-crimping step is a step of moving the first crimping head and temporarily crimping the mounted component to the circuit board, and the pre-crimping step is The two crimping head is heated until it reaches a final crimping temperature higher than the temperature of the second crimping stage, and the circuit board is disposed on the second crimping stage side so that the mounting component is temporarily crimped. A step of installing the circuit board thus mounted on the second pressure-bonding stage, and the step of main-bonding is a step of moving the second pressure-bonding head and finally pressure-bonding the temporarily-bonded mounted component to the circuit board. It was set as the manufacturing method of the electronic device characterized by these.

(3) In the method for manufacturing an electronic device according to (1) or (2), the temporary pressure bonding temperature is the highest temperature lower than the curing start temperature of the anisotropic conductive material. It was set as the manufacturing method.

(4) In the method for manufacturing an electronic device according to any one of (1) to (3), the temporary pressure bonding temperature is such that a curing reaction rate of the anisotropic conductive material is 1% or more and 10% It was set as the manufacturing method of the electronic device characterized by being the temperature used as below.

(5) In the electronic device manufacturing method according to any one of the above (1) to (4), the provisional pressure bonding temperature is 80 ° C. to 100 ° C.

(6) In the method for manufacturing an electronic device according to any one of (1) to (5), the temporary crimping step includes moving the crimping head and temporarily crimping the mounting component to the circuit board. The method of manufacturing an electronic device is characterized in that the pressure-bonding head is moved until the conductive particles contained in the anisotropic conductive material come into contact without being crushed.

  (7) In the method for manufacturing an electronic device according to any one of (1) to (6), the main pressing temperature is a temperature at which a curing reaction rate of the anisotropic conductive material reaches 80% or more. It was set as the manufacturing method of the electronic device characterized.

(8) An electronic device for electrically connecting the first electrode and the second electrode by thermocompression bonding a circuit board having the first electrode and a mounting component having the second electrode through an anisotropic conductive material. In the manufacturing apparatus, mounting means for mounting an anisotropic conductive material on the first electrode of the circuit board;
Positioning means for positioning the first electrode of the circuit board and the second electrode of the mounting component so as to face each other; mounting means for mounting the mounting component on the anisotropic conductive material; a first crimping stage; A first pressure-bonding head, heating means for heating the first stage and the first head until reaching the pre-bonding temperature, and a circuit board on which the mounting component is mounted are disposed on the first pressure-bonding stage. A first moving means, a temporary pressure-bonding portion for moving the first pressure-bonding head to temporarily pressure-bond the mounted component to the circuit board, a second pressure-bonding stage and a second pressure-bonding head, and the second pressure-bonding head. Heating means for heating the head temperature until reaching the main pressure bonding temperature higher than the temperature of the first pressure bonding head, and a second for placing the circuit board on which the mounting component is temporarily pressure-bonded on the second pressure bonding stage. Transfer And means, and a pressure bonding unit for the crimping of the mounted components on the circuit board by moving the second bonding head, and an apparatus for manufacturing an electronic device comprising a.

  In the present invention, a mounting component having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient of the circuit board is prepared, and is temporarily bonded after being raised to the temporary pressing temperature. Therefore, at the time of this temporary pressure bonding, the circuit board is temporarily fixed in a state where thermal expansion is larger than that of the mounted component. At the time of the main pressure bonding, the temperature of the pressure bonding stage is lower than that of the pressure bonding head. For this reason, the circuit board has a smaller thermal expansion than the mounted component. As a result, when cooled to room temperature, the thermal expansion difference between the circuit board and the mounted component is canceled, and there is an advantage that an electronic device with less warpage can be obtained.

An electronic device manufacturing method according to an embodiment of the present invention includes the following steps. First, there is a preparation step of preparing a mounting component having a linear thermal expansion coefficient smaller than that of the circuit board. And it has the mounting process which mounts the circuit board which has the 1st electrode on the mounting component which has the 2nd electrode via an anisotropic conductive material. At that time, the first electrode and the second electrode are positioned and placed so as to face each other. In addition, there is a pre-crimping pre-step in which the crimping stage and the crimping head are heated until reaching the temporary crimping temperature and the circuit board on which the mounting component is mounted is placed so that the circuit board is on the crimping stage side. And it has the temporary crimping | compression-bonding process which lowers | hangs a crimping | compression-bonding head, for example, and temporarily crimps | bonds a mounted component to a circuit board. Next, a pre-crimping pre-step is performed in which the crimping head is heated until reaching a final crimping temperature higher than the temperature of the crimping stage, and the pre-crimped mounting component and circuit board are placed so that the circuit board is in contact with the crimping stage. Have. And it has the final press-bonding process of carrying out the main press-bonding of the mounting component temporarily lowered by lowering the pressure-bonding head, for example.

  In the above embodiment, after the mounting step of mounting the mounting component on the circuit board via the anisotropic conductive material, the pre-crimping step of installing the circuit board on which the mounting component is mounted on the crimping stage is performed. Like to do. However, instead of this, the mounting step can be performed in the pre-temporary pressure bonding step. That is, as a pre-crimping pre-step, the crimping stage and the crimping head are heated to a temporary crimping temperature, the circuit board is placed on the crimping stage, and the mounting component is adsorbed to the crimping head, thereby Positioning is performed by making the electrode and the second electrode of the mounting component face each other through an anisotropic conductive material.

  Here, the circuit board is a liquid crystal display panel, and the mounting component is an IC chip for driving the liquid crystal display panel. That is, it is intended for a liquid crystal display device made of COG in which an IC chip is mounted on a glass substrate. In addition to the liquid crystal display panel, organic EL light emitting elements and other printed boards can be targeted. In addition to the IC chip, the mounting component can be a flexible sheet or the like. When a liquid crystal display panel is applied as a circuit board, the linear thermal expansion coefficient of the substrate glass is, for example, about 4.8 ppm / K, and the linear thermal expansion coefficient of the silicon substrate of the IC chip is, for example, about 3 ppm / K. An IC chip as a component can have a smaller linear thermal expansion coefficient than a glass substrate as a circuit board.

  As the anisotropic conductive material, an anisotropic conductive film or anisotropic conductive paste in which conductive particles are dispersed in a thermosetting resin can be used. In these films and pastes, the electrodes in the vertical direction are electrically connected to each other after the thermocompression bonding, but have insulation between the electrodes in the horizontal direction. As a component of the thermosetting resin, an epoxy resin, an acrylic resin, a polyester resin, or the like can be used.

  At the time of provisional pressure bonding in the present embodiment, the thermal expansion of the circuit board per unit length is larger than the thermal expansion of the mounting parts due to the difference in coefficient of linear thermal expansion between the circuit board and the mounting parts. Therefore, if it cools as it is, it will warp convexly from the circuit board toward the mounting component. However, at the time of the final press bonding, the temperature of the mounted component is higher than that of the circuit board. Therefore, when cooling is performed after the main pressure bonding, a concave reverse warping stress acts from the circuit board toward the mounted component due to a difference in thermal expansion. For this reason, there is an advantage that the stress causing the warp is offset, and as a result, the warp of the circuit board is reduced. In addition, in the pre-bonding pre-bonding process, the circuit board and the mounting component are installed on the bonding stage or the bonding head that has already been heated to the temporary bonding temperature or near the temporary bonding temperature, so there is no need to heat the bonding stage or the bonding head from room temperature. There is an advantage that the pressure bonding can be performed in a short cycle time.

  The crimping stage and the crimping head include a first crimping stage and a first crimping head, a second crimping stage, and a second crimping head. Then, in the pre-bonding step, the first pressure-bonding stage and the first pressure-bonding head are heated until reaching the pressure-bonding temperature, and the circuit board is arranged on the first pressure-bonding stage side to mount the circuit board on which the mounting component is mounted. 1 Install on the crimping stage. Then, in the temporary pressure bonding step, the first pressure bonding head is lowered to temporarily pressure-mount the mounted component to the circuit board. Next, in the pre-crimping pre-process, the second crimping head is heated until it reaches a final crimping temperature higher than the temperature of the second crimping stage, and the circuit board is placed on the second crimping stage side so that the mounting component is temporarily crimped. The circuit board thus formed is placed on the second pressure-bonding stage. Then, in the final crimping step, the second crimping head is lowered, for example, and the temporarily mounted component is crimped to the circuit board.

  That is, the first pressure-bonding stage and the first pressure-bonding head are dedicated to temporary pressure bonding, and the second pressure-bonding stage and the second pressure-bonding head are dedicated to main pressure bonding. Thereby, the time for raising the temperature of the pressure bonding head from the temporary pressure bonding to the main pressure bonding can be shortened. As a result, the cycle time for mounting the mounted component on the circuit board can be shortened.

  The temporary pressure bonding temperature is set to the highest temperature lower than the curing start temperature of the anisotropic conductive material. The temperature of the temporary press bonding is set to the highest temperature lower than the curing start temperature, and the thermal expansion on the circuit board side is made larger than the thermal expansion on the mounted component side. And at the time of this crimping, the mounting component is heated to a higher temperature than the circuit board so that the thermal expansion on the mounting component side is larger than the thermal expansion on the circuit board side to compensate for the difference in thermal expansion, thereby returning to room temperature. Try to reduce warping.

  Moreover, the temperature at which the curing reaction rate of the anisotropic conductive material is 1% or more and less than 10% can be set as the temporary pressure bonding temperature. In order to be able to compensate for the thermal expansion difference between the circuit board and the mounting component at the time of temporary pressing, the circuit board and the mounting component need to be fixed to each other at the time of temporary pressing. Therefore, the adhesive of the anisotropic conductive material needs to generate a curing reaction. For example, when a polyimide system is used as the adhesive, it is desirable that the imidization reaction is accelerated to about 1% to 10%. When using an epoxy system, it is desirable that the curing reaction by polymerization of the epoxy resin is accelerated to about 1% to 10%.

  In addition to the above, the thermosetting resin component in the adhesive contained in the anisotropic conductive material includes a (meth) acryl compound, an acrylic resin, a urethane compound, a urethane resin, an unsaturated polyester resin, a phenol resin, and the like. Things can be used. Furthermore, the form of the curing reaction of the thermosetting resin may use any polymerization form such as radical polymerization of double bonds, ionic polymerization of epoxy resin, or polyaddition. Moreover, the case where the film formation polymer which does not thermoset itself is contained may be sufficient. Moreover, a radical polymerization initiator, an epoxy curing agent, and a silane coupling agent may be included as additives.

  Moreover, it sets to 50 to 120 degreeC as temporary crimping | compression-bonding temperature. Moreover, Preferably it sets to 80 to 100 degreeC. The temperature difference between the crimping stage and the crimping head is set within ± 20 ° C., more preferably within ± 5 ° C. When a liquid crystal display element is used as a circuit board, if the liquid crystal display element is heated to a high temperature, the liquid crystal is decomposed or the polarizing plate is deteriorated. Therefore, the temperature cannot be set too high. Moreover, it is because a circuit board and a mounting component will not be fixed if the temporary crimping | compression-bonding temperature is made low.

  In the temporary crimping step, when the crimping head is moved and the mounting component is temporarily crimped to the circuit board, the crimping head is kept in contact with the conductive particles contained in the anisotropic conductive material without being crushed. A moving distance may be set. At this time, the circuit board and the mounting component are in a state where the conductive particles are in contact without being crushed, and the distance between the electrodes is 3 to 10 μm, which is equal to the diameter of the conductive particles. In order to adhere and fix in this state, the smaller the diameter of the conductive particles, the smaller the distance between the electrodes, and the heat from the mounted component to the circuit board is quickly transmitted.

  In this way, when the conductive particles are bonded and fixed without being crushed, the temperature of the pressure-bonding head can be set lower by 15 ° C. to 25 ° C. in the next main pressure bonding step in which the anisotropic conductive material is cured by thermocompression bonding. For this reason, the mounted component is 25 ° C. to 35 ° C. higher than the circuit board, and the difference between the thermal expansion on the mounted component side and the thermal expansion on the circuit board side can be minimized.

  Further, the main pressing temperature is a temperature at which the curing reaction rate of the anisotropic conductive material reaches 80% or more. This is because when the curing rate reaches 80% or more, temperature change, moisture resistance, and other environmental properties are improved. When an anisotropic conductive film is used as the anisotropic conductive material, the main pressure bonding temperature of the pressure bonding head is set in a range of 150 ° C. to 250 ° C. The crimping stage is set to a temporary crimping temperature. That is, it is set within the range of 50 ° C to 120 ° C, more preferably within the range of 80 ° C to 100 ° C. The pressure of the pressure-bonding head is a pressure at which the diameter of the conductive particles contained in the anisotropic conductive material is crushed by 1/4 to 3/4.

  The electronic device manufacturing apparatus according to the embodiment of the present invention has the following configuration. Mounting means for mounting an anisotropic conductive material on the first electrode on the circuit board, positioning means for positioning the first electrode of the circuit board and the second electrode of the mounting part opposite to each other, and the mounting part Mounting means for mounting on the anisotropic conductive material. In addition, a first pressure-bonding stage and a second pressure-bonding head for temporary pressure bonding, a first heating means for heating both the first pressure-bonded stage and the first pressure-bonded head until the temperature for temporary pressure bonding is reached, and a mounting component are mounted. And a first moving means for placing the circuit board on the first stage, and having a temporary pressure bonding portion for lowering the first pressure bonding head relative to the mounting component and performing temporary pressure bonding. Yes. Further, the second pressure bonding stage and the first pressure bonding head, the second heating means for heating the temperature of the second pressure bonding head until reaching the main pressure bonding temperature higher than the temperature of the second pressure bonding stage, and the mounting component are temporarily mounted. And a second moving means for placing the pressure-bonded circuit board on the second pressure-bonding stage, and having a main pressure-bonding portion for lowering the second pressure-bonding head relatively and abutting against the mounting component to perform the pressure-bonding. is doing.

  That is, a circuit board on which mounting components are mounted via an anisotropic conductive material is installed on a first pressure-bonding stage that has already been heated to a temporary pressure-bonding temperature, and the first pressure-bonding head that has already been heated to the temperature for temporary pressure-bonding Similarly, the second pressure-bonding stage is already set to a predetermined temperature lower than the main pressure-bonding temperature, and the second pressure-bonding head is set to the main pressure-bonding temperature. A circuit board on which the mounting component is temporarily crimped can be placed on the two crimping stage, and the second crimping head can be lowered to perform the final crimping. Therefore, since it is not necessary to change the pressure-bonding stage and the pressure-bonding head from a low temperature to a high temperature or from a high temperature to a low temperature, the main pressure bonding can be performed in a short time.

  Note that the transfer unit may include the above-described placement unit, positioning unit, and mounting unit. In addition, instead of this, the temporary pressing part may have the positioning means and the mounting means. That is, the circuit board is placed on the first pressure-bonding stage, and the mounting component is sucked by the pressure-bonding head. In this state, the first electrode of the circuit board and the second electrode of the mounting component are positioned by the positioning means, and the anisotropic The conductive material is mounted on the circuit board by mounting means. As a result, it is not necessary to provide a positioning means, a holding means for holding the mounted component, or the like in the transfer portion, and the cost of the electronic device manufacturing apparatus can be reduced and the productivity can be improved.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

  FIG. 1 shows sectional views of an electronic device according to an embodiment of the present invention in the order of manufacturing steps. Fig.1 (a) is sectional drawing of the glass substrate 1 as a circuit board in which the 1st electrode 2 was formed in the surface. First, as shown in FIG. 1A, a glass substrate 1 as a circuit board and an IC chip 4 as a mounting component to be mounted on the circuit board are prepared. In this case, the linear thermal expansion coefficient of the glass substrate 1 is larger than the linear thermal expansion coefficient of the IC chip 4 (preparation step). The glass substrate 1 is a part of a liquid crystal display panel (not shown). The 1st electrode 2 is comprised by the metal electrode or the transparent electrode.

  FIG. 1B shows a state where an anisotropic conductive film 3 as an anisotropic conductive material is placed on the first electrode 2 of FIG. Since the surface of the anisotropic conductive film 3 is adhesive, it can be fixed on the first electrode 2 and the glass substrate 1 by this adhesive force.

  FIG. 1C shows a state where an IC chip 4 as a mounting component is mounted on the anisotropic conductive film 3. The second electrode 5 formed on the surface of the IC chip 4 and the first electrode 2 formed on the glass substrate 1 are aligned to face each other and temporarily fixed by the adhesive force on the surface of the anisotropic conductive film. (Installation process).

  FIG. 1D is a schematic cross-sectional view showing a state in which the glass substrate 1 on which the IC chip 4 is placed on the pressure-bonding stage 6 is placed via the anisotropic conductive film 3 and temporary pressure bonding is performed. . In this case, the pressure-bonding stage 6 and the pressure-bonding head 7 are heated in advance to a temporary pressure-bonding temperature. The glass substrate 1 on which the IC chip 4 is placed is placed on the pressure-bonding stage 6 via the anisotropic conductive film 3 (pre-pressure bonding pre-step). Then, the crimping head 7 is lowered and brought into contact with the IC chip 4 for thermocompression bonding (temporary crimping process). Thereby, the IC chip 4 and the glass substrate 1 are fixed.

Further, in the electronic device manufacturing method that simultaneously executes the mounting process of FIG. 1C and the pre-bonding process of FIG. 1D, the IC chip 4 is adsorbed by the crimping head 7 and formed on the surface of the IC chip 4. The second electrode 5 and the first electrode 2 formed on the glass substrate 1 are aligned to face each other, and the crimping head 7 is lowered to place the IC chip 4 through the anisotropic conductive film 3. The glass substrate 1 is placed and thermocompression bonded. In this case, the pressure-bonding stage 6 and the pressure-bonding head 7 are heated in advance to a temporary pressure-bonding temperature. Thereby, the IC chip 4 and the glass substrate 1 are fixed by temporary pressure bonding. Here, when the clearance between the IC chip 4 and the glass substrate 1 is the same distance as the diameter of the conductive particles of the anisotropic conductive film 3, the difference between the thermal expansion on the mounting component side and the thermal expansion on the circuit board side is calculated. Can be minimized.

  Here, the temporary pressure bonding temperature was 100 ° C. Moreover, it can set to the highest temperature below the hardening start temperature of the anisotropic conductive film 3, without setting the temporary crimping | compression-bonding temperature to 100 degreeC. Moreover, the curing reaction rate of the anisotropic conductive film 3 after temporary press-bonding can be set to a temporary press-bonding temperature that is 1% or more and less than 10%. This is because the temporary pressure bonding temperature requires the IC chip 4 and the glass substrate 1 to be fixed, and is affected by the adhesive material and the like contained in the anisotropic conductive film 3.

FIG. 1E is a schematic cross-sectional view showing a state in which the IC chip 4 and the glass substrate 1 that have been temporarily press-bonded are placed on the press-bonding stage and the main press-bonding is performed. In this case, the temperature of the pressure-bonding head 7 is heated in advance to the main pressure-bonding temperature higher than the temperature of the pressure-bonding stage 6, and the glass substrate 1 on which the IC chip 4 is mounted is placed on the pressure-bonding stage 6 (before the main pressure bonding). Process). The crimping head 7 is lowered and brought into contact with the IC chip 4 to perform final crimping (final crimping process). The anisotropic conductive film 3 becomes a solution at the main pressing temperature and oozes out into the gap between the IC chip 4 and the glass substrate 1 and is cured. Although the conductive particles are dispersed in the anisotropic conductive film 3, since the particles are dispersed or dispersed between the first electrode and the second electrode, the adjacent electrodes are kept insulative. The first electrode 2 and the second electrode 5 are electrically connected through conductive particles. After a predetermined time, cool to room temperature. The main pressure bonding temperature was 185 ° C. Moreover, it can be set as the temperature which the hardening reaction rate of the anisotropic conductive film 3 reaches 80% or more as this crimping | compression-bonding temperature. This is because by setting the curing reaction rate to 80% or more, reliability such as the adhesive strength between the IC chip 4 and the glass substrate 1 can be ensured.

  In the above description, in the temporary pressure bonding step, temporary pressure bonding is performed by the first pressure bonding stage and the first pressure bonding head, and in the main pressure bonding step, the second pressure bonding stage and the second pressure bonding head are used and separated from each other. A crimping tool can be used. By separating in this way, it is not necessary to change each stage and head from low temperature to high temperature and from high temperature to low temperature. Therefore, the time for the entire crimping process can be shortened. For example, an IC chip can be mounted on one circuit board by thermocompression bonding with a cycle time of 5 seconds or less.

  Next, actual measurement results of the warpage of the glass substrate at each stage in the mounting process will be described.

  FIG. 2 is a graph showing the result of measuring the amount of warpage in the mounting region of the glass substrate 1 before mounting the IC chip 4 as the mounting component on the glass substrate 1 as the circuit board from the back side of the glass substrate 1. The horizontal axis is the length (mm) of the glass substrate 1, and the vertical axis is the amount of warpage (μm). The glass substrate 1 before mounting is curved in a convex shape. That is, when viewed from the IC chip 4 side, it is curved in a concave shape. The amount of warpage between the central portion and the peripheral portion was 17.2 μm.

  FIG. 3 is a graph showing the result of measuring the amount of warpage of the glass substrate 1 by the same method after temporarily pressing the IC chip 4 to the glass substrate 1. Similar to FIG. 2, when viewed from the IC chip 4 side, the glass substrate 1 is curved in a concave shape. However, the amount of warpage between the central portion and the peripheral portion was about 14 μm, and the amount of warpage of the initial glass substrate 1 decreased by about 3 μm. This is because the glass substrate 1 has a larger coefficient of linear thermal expansion than the IC chip 4, and therefore when the glass substrate 1 is returned from the pre-bonding temperature to room temperature, the glass substrate 1 side contracts more.

  FIG. 4 is a graph showing the results of measuring the amount of warpage by the same method as described above after the temporary compression bonding of the IC chip 4 and the glass substrate 1 are performed. That is, when viewed from the IC chip 4 side, the glass substrate 1 is curved in a concave shape. The amount of warpage was about 20.2 μm between the central portion and the peripheral portion. Therefore, if the initial warpage amount is subtracted, the warpage amount after arrival and departure is about 3 μm. In the conventional method in which temporary pressure bonding is not performed, the warping amount is about 5 μm under the same main pressure bonding conditions. This about 5 μm is equivalent to the level of warpage (20.2 μm−14 μm = 6.2 μm) generated between FIGS. Therefore, according to the manufacturing method according to the present embodiment, the amount of warpage of the glass substrate 1 can be reduced by 40% or more compared to this conventional method. As a result, when the glass substrate 1 is a liquid crystal display cell, an increase in warpage due to the mounting of the IC chip 4 is reduced, and color unevenness is prevented from occurring in the vicinity of the mounting region of the IC chip 4 of the liquid crystal display cell. can do.

  FIG. 5 is a table showing the results of comparing the amount of warpage of an electronic device manufactured by the manufacturing method according to the present embodiment and the amount of warpage of an electronic device manufactured by a conventional method that does not include a provisional pressure bonding step. The provisional pressure bonding conditions, the main pressure bonding conditions, and the samples used are the same as the samples shown in FIGS.

  In FIG. 1-No. 5 represents the amount of warpage of an electronic device according to a conventional method in which temporary bonding is not performed. 6-No. 10 represents the amount of warp of the electronic device by the manufacturing method according to the present embodiment. The first column of FIG. 5 is the initial warp amount of the glass substrate 1, the second column is the warp amount after temporary press-bonding, the parentheses are the warp amount after subtracting the initial warp amount from the warp amount after temporary press-bonding, the third column Is the amount of warpage after final crimping, the amount in the parenthesis is the amount of warpage after subtracting the amount of warpage after temporary crimping, and the fourth column is after the COG after subtracting the initial amount of warpage from the amount of warpage after final crimping The amount of warpage of each is shown. Sample No. by the manufacturing method according to the present embodiment. 6-No. In any of the samples of No. 10, the amount of warpage after COG is the same as the sample No. 10 according to the conventional method. 1-No. Smaller than any of 5 samples. It can be understood that the amount of warpage is about 1.5 μm smaller on average.

  FIG. 6 is a schematic plan view of the electronic device manufacturing apparatus 10 according to the present embodiment. The electronic device manufacturing apparatus 10 includes a loader unit 11 that conveys a liquid crystal display panel that is a circuit board, an ACF transfer unit 12 that places the anisotropic conductive film 3 on the electrodes of the liquid crystal display panel, and an anisotropic conductive material. An unloader that transports a liquid crystal display panel that is an electronic device on which the IC chip 4 is mounted, a temporary pressure-bonding portion 13 that performs temporary pressure bonding by mounting the IC chip 4 on the film 3, a main pressure-bonding portion 14 that performs final pressure bonding. Part 15.

  First, a liquid crystal display panel as a circuit board is conveyed via a loader 16 and a loader 17. The transported liquid crystal display panel is taken out by an ACF sticking machine 18 as a mounting means, and the anisotropic conductive film 3 is attached to the first electrode 2 on the glass substrate 1 of the liquid crystal display panel. The liquid crystal display panel in which the anisotropic conductive film 3 is bonded onto the glass substrate 1 is conveyed by the conveyor 19. The conveyed liquid crystal display panel is moved to the temporary pressure bonding machine 23.

  On the other hand, the IC chip 4 is taken out from the IC tray 28 of the chip loader 29 by the XY robot 20, placed on the conveyor 21, and conveyed. The IC reversing machine 22 serving as a mounting means takes out the IC chip 4 on the conveyor 21, reverses the second electrode of the IC chip 4 to the lower part, and mounts it on the anisotropic conductive film 3 on the liquid crystal display panel. When mounting, alignment between the first electrode 2 on the glass substrate 1 of the liquid crystal display panel and the second electrode 5 of the IC chip 4 is performed by alignment means (not shown). The liquid crystal display panel on which the IC chip 4 is mounted is placed on a first crimping stage of a temporary crimping machine (not shown). The first pressure-bonding stage and the first pressure-bonding head are equipped with heating means inside and controlled by a temporary pressure-bonding temperature control means. The temporary pressure bonding temperature control means detects that the first pressure bonding stage and the first pressure bonding head have reached the temporary pressure bonding temperature, and lowers the first pressure bonding head to perform temporary pressure bonding.

  The liquid crystal display panel on which the IC chip is temporarily bonded is conveyed by the conveyor 24 and taken out to the main bonding machine 25. The present crimping machine includes a second crimping stage and a second crimping head (not shown), and each of the second crimping stage and the second crimping head includes a heating unit. These heating means are controlled by the main pressure bonding temperature control means. The liquid crystal display panel moved to the main crimping machine 25 is placed on the second crimping stage, and the main crimping control means detects that the temperature of the crimping head has reached the final crimping temperature and lowers the second crimping head. Perform final crimping. The second pressure-bonding stage at the time of the main pressure bonding is set to a temporary pressure-bonding temperature. The liquid crystal display panel for which the main press bonding has been completed is conveyed by the conveyor 26 and the conveyor 27.

It is sectional drawing which shows the manufacturing method of the electronic device which concerns on embodiment of this invention. It is a graph showing the curvature amount of the glass substrate before mounting which concerns on embodiment of this invention. It is a graph showing the curvature amount of the glass substrate after the temporary crimping | compression-bonding which concerns on embodiment of this invention. It is a graph showing the curvature amount of the glass substrate after this press-bonding which concerns on embodiment of this invention. It is a list which shows the experimental result showing the curvature amount of the electronic device which concerns on embodiment of this invention. 1 is a schematic plan view showing an electronic device manufacturing apparatus according to an embodiment of the present invention. It is typical sectional drawing which shows the conventionally well-known COG mounting method. It is explanatory drawing for demonstrating the cause which a glass substrate warps after conventionally well-known crimping | compression-bonding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 1st electrode 3 Anisotropic conductive film 4 IC chip 5 2nd electrode 6 Crimp stage 7 Crimp head

Claims (8)

An anisotropic conductive material is interposed between a circuit board having a first electrode and a mounting component having a second electrode, and the first electrode and the second electrode are heated and pressure-bonded by a pressure-bonding stage and a pressure-bonding head. In an electronic device manufacturing method for electrically connecting
A preparation step of preparing the circuit board, and the mounting component having a smaller linear thermal expansion coefficient than the circuit board;
A mounting step of positioning the first electrode of the circuit board and the second electrode of the mounting component opposite to each other through an anisotropic conductive material, and mounting the mounting component on the anisotropic conductive material;
The pressure bonding stage and the pressure bonding head disposed opposite to the pressure bonding stage are heated until reaching a temporary pressure bonding temperature, and the circuit board is disposed on the pressure bonding stage side and the circuit board on which the mounting component is mounted is pressure bonded. A pre-bonding process to be installed on the stage;
A temporary crimping step of moving the crimping head and temporarily crimping the mounted component to the circuit board;
The crimping head is heated until it reaches a final crimping temperature higher than the temperature of the crimping stage, and the circuit board is placed on the crimping stage side and the circuit board on which the mounting component is temporarily crimped is applied to the crimping stage. The main crimping pre-installation process to be installed;
A final crimping step of moving the crimping head and subjecting the temporarily crimped mounting component to the circuit board. The crimping stage and the crimping head comprise a first crimping stage, a first crimping head, a second crimping stage, and a second crimping head,
In the pre-crimping pre-process, the first crimping stage and the first crimping head are heated until reaching the temporary crimping temperature, and the circuit board is arranged on the first crimping stage side to mount the mounting component. A step of installing a circuit board on the first crimping stage;
The temporary pressure bonding step is a step of moving the first pressure bonding head and temporarily pressure bonding the mounted component to the circuit board,
In the pre-crimping pre-step, the second crimping head is heated until reaching a final crimping temperature higher than the temperature of the second crimping stage, and the circuit board is disposed on the second crimping stage side to mount the mounting component. Is a step of installing the circuit board, which has been temporarily pressure-bonded, on the second pressure-bonding stage,
2. The method of manufacturing an electronic device according to claim 1, wherein the main press-bonding step is a step of moving the second pressure-bonding head and finally press-bonding the temporarily-bonded mounted component to the circuit board. .   The method of manufacturing an electronic device according to claim 1, wherein the temporary pressure bonding temperature is the highest temperature lower than a curing start temperature of the anisotropic conductive material.   The said temporary press-bonding temperature is a temperature at which the curing reaction rate of the anisotropic conductive material is 1% or more and less than 10%. Electronic device manufacturing method.   The method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the temporary pressure bonding temperature is 80 ° C to 100 ° C.   In the temporary crimping step, the crimping head is moved to move the crimping head until the conductive particles contained in the anisotropic conductive material come into contact without being crushed when the mounting component is temporarily crimped to the circuit board. The manufacturing method of the electronic device of any one of Claims 1-5 characterized by the above-mentioned.   The method for manufacturing an electronic device according to claim 1, wherein the main press bonding temperature is a temperature at which a curing reaction rate of the anisotropic conductive material reaches 80% or more. In an electronic device manufacturing apparatus in which a circuit board having a first electrode and a mounting component having a second electrode are thermocompression bonded via an anisotropic conductive material to electrically connect the first electrode and the second electrode. Mounting means for mounting an anisotropic conductive material on the first electrode of the circuit board;
Positioning means for positioning the first electrode of the circuit board and the second electrode of the mounting component opposite to each other;
Mounting means for mounting the mounting component on the anisotropic conductive material;
A first pressure-bonding stage and a first pressure-bonding head; heating means for heating the first stage and the first head until reaching a temporary pressure-bonding temperature; and a circuit board on which the mounting component is mounted. A first moving means for installing the first crimping head, and a temporary crimping portion for temporarily crimping the mounting component to the circuit board by moving the first crimping head;
A second pressure-bonding stage and a second pressure-bonding head; heating means for heating the second pressure-bonding head until the temperature reaches a main pressure-bonding temperature higher than the temperature of the first pressure-bonding head; A second moving means for placing the circuit board on the second pressure-bonding stage, and a main pressure-bonding portion for moving the second pressure-bonding head and finally pressure-bonding the mounted component to the circuit board. Electronic device manufacturing equipment.

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