JP2004179398A - Electronic component mounting method, electronic component mounting substrate, electrooptical apparatus, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component mounting method capable of minimizing the consumption of conductive particles, achieving the high density packaging of a driver IC and a mounting substrate, and improving reliability in electric junction. <P>SOLUTION: In the mounting method, an electronic component is used. In the electronic component, a bump is provided, where the bump is electrically connected to a plurality of pieces of electrode wiring by a bonding element to a substrate, where the plurality of pieces of electrode wiring are provided, and has a projection at a connection section with the substrate. The projection projects toward a substrate side at least from the end of the bump and is provided at an edge, where the bumps are adjacent each other. Additionally, the mounting method includes a process for arranging a bonding layer on the electrode wiring provided on the substrate, a process for arranging the conductive particles on the electrode wiring provided on the substrate, and a process for curing the bonding layer while applying pressure to the substrate and the electronic component for electrically connecting the substrate to the electronic component. In the process for arranging the conductive particles, a droplet material is delivered from a nozzle for arranging the conductive particles. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic component that is electrically connected to a board and a mounting board for the electronic component. In addition, the present invention relates to an electro-optical device, an electrophoretic device, and an electronic device configured using the mounting substrate.
[0002]
[Background Art]
2. Description of the Related Art In general, an electro-optical device such as a liquid crystal display device or an EL (Electro Luminescence) device forms a panel structure by arranging an electro-optical material such as a liquid crystal and an EL between substrates, and further includes a circuit in which an appropriate electronic circuit is mounted. It is formed by connecting a substrate to the panel structure. In addition, electronic components, for example, chip components such as electrolytic capacitors, IC chips, and the like are often mounted on the circuit board.
[0003]
It is widely known that there is a mounting method based on SMT (Surface Mount Technology) as a method for mounting electronic components, particularly chip components, on a circuit board. The mounting method based on the SMT is basically a mounting method using a reflow soldering process. For example, this method is a mounting method including a step of mounting an electronic component on a substrate on which solder is mounted, and then heating the solder to solder the electronic component to the substrate.
[0004]
As a method for mounting electronic components, particularly IC chips, on a circuit board, there is a mounting method based on COF (Chip on Film). The mounting method based on the COF is basically based on thermocompression bonding to the mounting area of the IC chip. That is, in the mounting method using the COF, an IC chip is generally mounted on a substrate by thermocompression bonding, that is, pressurization and heating, using an adhesive element such as an ACF (Anisotropic Conductive Film). The anisotropic conductive film is electrically connected by pressing the connection portion between the mounting substrate and the IC chip with a heated head to cure the adhesive layer. Generally, the ACF has a sheet-like structure in which metal particles having a diameter of several μm, metal-coated plastic particles, and the like are dispersed and arranged in an adhesive layer having a thickness of several tens μm. Then, the particles are plastically changed by thermocompression bonding up to the diameter of the conductive particles to electrically connect the substrate and the IC chip.
[0005]
Another example of the adhesive element is a method using a conductive adhesive obtained by mixing a plurality of conductive particles in an adhesive resin. The conductive particles are composed of a core material formed of a synthetic resin and a conductive material covering the core material. The core material is formed of a material having a property that the heat deformation temperature is higher than the heat deformation temperature of the bonding resin, for example, polyphenylene oxide, polysulfone, or the like. By using this method, a highly reliable conductive adhesive that can withstand the high temperature of the reflow soldering process is provided (see Patent Document 1).
[0006]
[Patent Document 1]
JP 2000-219864 A
[0007]
[Problems to be solved by the invention]
In recent years, electro-optical devices, for example, liquid crystal display devices and the like have been improved in definition, and accordingly, the wiring pitch on a mounting substrate has been increased in density. Therefore, the diameter of the conductive particles contained in the ACF is reduced to prevent a short circuit in the lateral direction between the bumps, and the number of particles is increased, thereby coping with high density. However, prevention of a lateral short circuit between bumps while keeping the connection resistance low is reaching a limit in the conventional mounting technology.
[0008]
In addition, the conductive particles contained in the ACF are relatively expensive, and are one of the factors that increase the mounting cost of an electronic component to be bonded using the ACF, for example, a method of electrically connecting a driver IC. ing. As described above, as the pitch of the wiring on the mounting board becomes narrower, it is necessary to reduce the diameter of the conductive particles and increase the mixing ratio of the conductive particles. However, when the compounding ratio of the conductive particles is increased, when the driver IC is bonded, the alignment marks on the mounting substrate side are obstructed by the conductive particles, so that pattern recognition becomes difficult during image processing. Further, the number of conductive particles present between the driver IC and the mounting board, that is, between the bumps of the driver IC and the board, which are involved in the electrical connection after mounting, is the number before the pressing. It decreases when compared with the number. This is because, during mounting, the conductive particles provided at the connection portion protrude from the connection portion between the bump of the driver IC and the substrate due to the pressing step. As a result, a small amount of conductive particles are present below the bumps of the driver IC, that is, at the connection portions, and the connection resistance may be increased. In addition, since the density of the mounting substrate is increasing, adjacent bumps may be electrically short-circuited.
[0009]
In addition, the conductive adhesive described in Patent Document 1 described above also exists between the bumps of the driver IC and the substrate, and the number of the conductive particles involved in the electrical connection after mounting is reduced. However, due to the pressurization during mounting, the number decreases as compared with the number before pressurization. In other words, there is a possibility that the amount of conductive particles existing in the lower part of the bump of the driver IC, that is, in the connection portion, becomes small, and the connection resistance increases. In addition, since the density of the mounting board has been increased, the adjacent bumps may be electrically short-circuited.
[0010]
The present invention has been made in view of the above points, and minimizes the consumption of conductive particles, enables high-density mounting of a driver IC and a mounting substrate, and improves the reliability of electrical bonding. It is to provide an electronic component that can be improved.
[0011]
[Means for Solving the Problems]
According to one aspect of the present invention, in the electronic component mounting method, an electronic component electrically connected to the plurality of electrode wirings by an adhesive element with respect to a substrate provided with the plurality of electrode wirings, The electronic device has a protrusion at a connection portion with the substrate, the electronic component has a bump at the connection portion, and the protrusion projects from at least an end of the bump toward the substrate. Is a mounting method of an electronic component in which at least the bumps are provided on adjacent edges. Then, the mounting method of the mounting component includes a step of arranging an adhesive layer on the electrode wiring provided on the substrate, a step of arranging the conductive particles on the electrode wiring provided on the substrate, Curing the adhesive layer while applying pressure to the electronic component, and electrically connecting the substrate and the electronic component, wherein the step of disposing the conductive particles comprises: The conductive particles are arranged by discharging a material. In the electronic component, by providing the projecting portion at the connection portion with the substrate, it is possible to improve the securing of the conductive particles provided on the substrate during thermocompression bonding. Further, in the electronic component, by providing the protruding portions on the sides adjacent to the bumps, a short circuit between the bumps can be prevented, and highly reliable electrical connection can be performed. In addition, since the above electronic components can prevent short-circuiting between bumps, highly reliable electrical connection can be performed even on a substrate having a high wiring pitch, and thus the wiring pitch is high. A highly reliable electrical connection can be made to the substrate, and high-density mounting is also possible.
[0012]
In the electronic component mounting method, it is preferable that the height of the protrusion has a value of 3 μm to 5 μm from an end of the bump. For example, when the diameter of the conductive particles is 5 μm and the height of the protrusion has a value of 3 μm to 5 μm, the conductive particles are captured well, and the conductive particles are satisfactorily captured at the bottom of the bump. Crushed.
[0013]
In one aspect of the electronic component mounting method, the step of arranging the conductive particles preferably includes arranging the conductive particles on the adhesive layer arranged on the electrode wiring. The adhesive layer may be, for example, a thermosetting resin such as an epoxy resin or a photo-setting resin.
[0014]
In another aspect of the electronic component mounting method, the conductive particles are preferably metal particles. Since the conductive particles are metal particles, good electrical connection between the substrate and the bumps can be achieved by the above steps.
[0015]
In another aspect of the electronic component mounting method, it is preferable that the surface of the conductive particles is covered with a film having an electrical insulating property. Since the insulating film is provided on the surface of the conductive particles, the insulating film between the substrate and the bump is broken in the vertical direction, in short, by the pressurization in the step, and the insulating film between the substrate and the bump is good. Electrical connection is possible.
[0016]
In another aspect of the electronic component mounting method, preferably, the conductive particles are metal-coated particles. Since the conductive particles are metal-coated particles, the above-described process enables good electrical connection between the substrate and the bumps.
[0017]
According to another aspect of the present invention, it is preferable that the electronic component mounting board is manufactured by the above-described electronic component mounting method. The mounting board for the electronic component may be, for example, a flexible printed circuit (FPC) board.
[0018]
According to another aspect of the present invention, an electro-optical device including the electronic component mounting substrate and a panel including an electro-optical material can be configured.
[0019]
In another aspect of the present invention, in the electro-optical device, the panel including the electro-optical material is a liquid crystal panel, and the electronic component can be a driving IC of the liquid crystal panel. The liquid crystal panel includes an STN (Super Twisted Nematic) mode, a TFT-LCD (Thin Film Transistor-Liquid Crystal Display), and a TFD-LCD (Thin Film Dynode-Liquid, and the above-described electric disperse, and the like. An electronic device including the optical device as a display portion can be configured.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0021]
In the present embodiment, a necessary number of conductive particles involved in the connection between the substrate and the driver IC are secured by providing a projection on an electronic component disposed on the mounting substrate, for example, a bump of the driver IC. It is characterized by improving reliability of dynamic connection and enabling high-density mounting.
[0022]
(Constitution)
FIG. 1 shows an example of a liquid crystal display device on which the substrate according to the present embodiment is mounted. FIG. 2 is a sectional view taken along line AA ′ of the liquid crystal display device 100 shown in FIG.
[0023]
In the liquid crystal panel 102, transparent electrode films 2a and 2b are respectively formed on the surfaces of a first substrate 1a and a second substrate 1b, which are insulating substrates made of glass, plastic, or the like, and liquid crystal molecules are aligned in a certain direction. An alignment film that is not provided is further provided. The first substrate 1a and the second substrate 1b are adhered to each other with a sealing material so that the above-mentioned transparent electrodes 2a and 2b face each other while maintaining a constant interval by a spacer (not shown). The liquid crystal layer 4 is sandwiched between the first substrate 1a and the second substrate 1b by filling the liquid crystal material in the gap between the first substrate 1a and the second substrate 1b. Further, polarizing plates 3a and 3b are provided outside the first substrate 1a and the second substrate 1b, respectively, and thereby, a liquid crystal panel 102 is formed. When a voltage is applied to the opposing transparent electrode films 2a and 2b, the arrangement of the liquid crystal molecules sandwiched therebetween changes, and the direction of the absorption axes of the polarizing plates 3a and 3b is changed from the backlight unit (not shown). The transmission and opacity of the light is controlled, and a desired display can be obtained.
[0024]
The driver IC 6 for driving the liquid crystal is mounted on the FPC board 103. The mounting method of the driver IC 6 is such that the conductive particles are arranged by discharging a droplet material from a nozzle onto the applied adhesive layer, and the driver IC 6 is thermo-compressed, so that electrical connection is performed. .
[0025]
When a conventional driver IC is used, the conductive particles may protrude from the electrical connection region during thermocompression bonding. That is, since the bumps of the conventional driver IC do not have the protruding edge, the conductive particles cannot be captured well. In such a case, the required number of conductive particles may not be satisfied in the electrical connection region, or adjacent bumps may be short-circuited by the conductive particles.
[0026]
However, since the driver IC 6 according to the present invention has the bumps provided with the protruding portions, the conductive particles are accurately captured in the electrical connection region. That is, the driver IC 6 can provide a highly reliable mounting board for electrical connection.
[0027]
Further, in the mounting method of the driver IC 6 according to the present invention, the conductive particles are arranged only in a necessary area, that is, only in an electric connection area. Therefore, waste of the conductive particles can be omitted, the cost advantage is high, and the possibility that adjacent bumps are short-circuited is low. In particular, since the bumps of the driver IC 6 according to the present invention have protruding edges, the conductive particles can be accurately captured, and good electrical connection can be made. In short, the FPC board 103 on which the driver IC 6 is mounted is a mounting board with good electrical connection.
[0028]
The electrode wiring 2b of the liquid crystal panel 102 and the electrode wiring 7a of the FPC board 103 are mounted via an ACF 5a. In this case, the ACF 5a is attached to the thermocompression bonding area 105 of the liquid crystal panel 102 where the electrode wiring 2b is provided, and the FPC board 103 is temporarily fixed. Then, thermocompression bonding is performed on the FPC board 103 and the thermocompression bonding area 105 of the liquid crystal panel 102 using a thermocompression bonding head. Thus, the electrode wiring 7a of the FPC board is electrically connected to the electrode wiring 2b of the liquid crystal panel 102 through the conductive particles in the ACF 5a.
[0029]
Further, an ACF 5b is mounted between the electrode wiring 7c of the FPC board 103 and the electrode wiring 9a of the PCB board 104 mounted by the SMT method. In this case, the ACF 6b is attached to the thermocompression bonding region 106 of the PCB substrate 104 where the electrode wiring 9a is provided, and the FPC substrate 103 is temporarily fixed. Then, the thermocompression bonding is performed on the thermocompression bonding area 106 of the FPC board 103 and the PCB board 104 using a thermocompression bonding head. Thus, the electrode wiring 7c of the FPC board is electrically connected to the electrode wiring 9a of the PCB board 104 through the conductive particles in the ACF 5b. The chip component 10 is fixed to the PCB substrate 104 by solder 11.
[0030]
(First Embodiment of Driver IC)
FIG. 3 shows a first example of the driver IC 6 according to the present embodiment.
[0031]
FIG. 3A is a perspective view in which the back side of the driver IC 6, that is, the side on which the bumps 6 a are provided is an upper side. FIGS. 3B and 3C are diagrams of the bumps 6 a of the driver IC 6. It is an enlarged side view.
[0032]
FIG. 3B is a side view of the bump 6a observed from the direction of the arrow L1 shown in FIG. A protrusion 6c is provided on the bump 6a of the driver IC 6. The protruding portion 6c is provided on a side where the bumps are adjacent to each other so that the adjacent bumps 6a do not short-circuit. The protrusion 6c is provided to accurately capture the conductive particles mounted on the substrate. The height of the protrusion 6c is preferably a value that is at least half the diameter of the conductive particles. For example, when the diameter of the conductive particles is 5 μm, the height of the protrusion 6c is preferably 3 μm or more and 5 μm or less.
[0033]
In the mounting technology, for example, in order to mount the driver IC on the substrate, an adhesive element such as an ACF is installed on the substrate, and the driver IC is mounted. Then, the driver IC is electrically connected and fixed using the thermocompression bonding head. As described above, when mounting is performed using the thermocompression bonding head, the conductive particles located under the bumps of the driver IC may protrude due to the pressure of the head. That is, after mounting, the number of conductive particles present under the bumps of the driver IC is smaller than the number of conductive particles existing before the thermocompression bonding step. In such a case, the number of conductive particles becomes insufficient, and there is a possibility that the electrical resistance between the substrate and the driver IC increases. In addition, since the conductive particles move to a region that does not require electrical connection, expensive conductive particles are wasted. Further, since the pitch of the wiring is being narrowed due to the high definition of the mounting substrate, the conductive particles may cause a short circuit between adjacent bumps.
[0034]
As described above, the driver IC 6 of the present embodiment is provided with the protrusion 6c below the bump 6a. In the example of FIG. 3, the protrusion 6c is provided on the side where the bumps are adjacent to each other. In the mounting method of the driver IC 6, the conductive particles are arranged by discharging a droplet material from a nozzle onto the applied adhesive layer, and the driver IC 6 is thermocompression-bonded to establish electrical connection. Is As described above, even if the driver IC 6 is thermocompression-bonded, the conductive particles are unlikely to protrude from the lower portion of the bump 6a because the protrusion 6c is provided on the bump 6a. That is, even when the thermocompression bonding head is pressed from above the driver IC 6, the conductive particles are satisfactorily crushed at the lower portion of the bump 6a by the protrusion 6c of the bump 6a, so that the driver IC 6 and the FPC board 103 are electrically connected well. Connection can be made. In addition, according to the present invention, since the driver IC 6 having the bumps 6a and the method of arranging the conductive particles for ejecting the droplet material from the nozzles are unlikely to exist in the region that is not involved in the electrical connection, the possibility is low. In addition, a short circuit between adjacent bumps does not easily occur. Therefore, the FPC board 103 can realize highly reliable electrical connection.
[0035]
As described above, according to the present invention, the conductive particles can achieve good electrical connection without protruding from the lower part of the bump 6a, and hardly exist in a region where the electrical connection is unnecessary. In addition, it is possible to realize a low-cost mounting substrate without waste of conductive particles. Further, the bumps 6a provided with the protruding portions 6c do not cause a short circuit between adjacent bumps, so that a highly reliable mounting substrate can be manufactured.
[0036]
Therefore, the driver IC 6 according to the present invention can provide a high-reliability, low-cost mounting board having good electrical connection.
[0037]
(Second embodiment of driver IC)
FIG. 4 shows a second example of the driver IC 6 in the present embodiment. FIG. 4A is a perspective view in which the back side of the driver IC 6, that is, the side on which the bumps 6b are provided is upward. FIG. 4B is a side view of the bump 6b of the driver IC 6 observed from the directions of the arrows L1 and L2 shown in FIG. FIG. 4C is a cross-sectional view taken along line BB ′ of the bump 6b shown in FIG. 4B.
[0038]
The bumps 6b of the driver IC 6 are provided with protrusions 6d on all four surfaces. The projecting portions 6d are provided on all four surfaces of the bumps 6b so that conductive particles disposed below the bumps 6b can be accurately captured, in addition to the purpose of preventing short circuit between the adjacent bumps 6b. Is provided. The height of the protrusion 6d is preferably a value that is at least half the particle size of the conductive particles. For example, when the particle size of the conductive particles is 5 μm, the height of the protrusion 6 d is preferably 3 μm or more and 5 μm or less.
[0039]
Even with the driver IC 6 having the bumps 6b provided with the protruding portions, it is possible to solve the problems of the related art as described above, such as a poor electrical connection between the FPC board and the driver IC, a short circuit between adjacent bumps, and the like. Can be.
[0040]
In the example shown in FIG. 4, a protrusion 6 d is provided on the bump 6 b of the driver IC 6. The protrusions 6d are provided on all four surfaces of the bump 6b. Therefore, the capture of the conductive particles mounted only in the electrical connection region can be further improved by using the driver IC 6 of the present embodiment. That is, after the driver IC 6 is thermocompression-bonded, the conductive particles do not protrude from the lower part of the bump 6b because the protrusions 6d are provided on all four surfaces of the bump 6b. The connection can be good. That is, even if the thermocompression bonding head is pressed from above the driver IC 6, the conductive particles are squashed well without protruding from the lower portion of the bump 6 b by the protrusion 6 d of the bump 6 b of the present invention, and Good electrical connection can be made between the bumps 6b. Also, due to the driver IC 6 having the bumps 6b and the method of arranging the conductive particles for discharging the droplet material from the nozzle, the conductive particles do not exist in the region not involved in the electrical connection, and the short-circuit between the adjacent bumps occurs. Does not occur. Therefore, the FPC board 103 can realize more reliable electrical connection.
[0041]
As described above, in the example shown in FIG. 4, the conductive particles can achieve good electrical connection without protruding from the lower portion of the bump 6b, and exist in a region where the electrical connection is unnecessary. Therefore, there is no waste of the conductive particles, and a low-cost mounting substrate can be realized. Further, the bumps 6b provided with the protruding portions 6d do not cause a short circuit between adjacent bumps, so that a highly reliable mounting substrate can be manufactured. Can respond.
[0042]
Therefore, the driver IC 6 shown in FIG. 4 has good electrical connection, high reliability, and can provide a mounting substrate that can cope with a narrow wiring pitch.
[0043]
(Manufacturing method example 1)
FIG. 5 shows a flowchart of the method of manufacturing the mounting board according to the present embodiment, and FIG. 6 shows details of a main process of a manufacturing process of the FPC board 103 in FIG.
[0044]
The manufacturing method example 1 is characterized in that the adhesive layer and the conductive particles are arranged using a method of discharging a droplet material from a nozzle.
[0045]
In step Pa1, the adhesive element 8a is mounted on the FPC board 103 only on the electrode wiring 7b that is an electrical connection area. The adhesive element 8a is discharged from the nozzle 13a as a droplet material, and is applied only to a necessary area. For the adhesive element 8a, for example, an epoxy resin of a thermosetting resin can be used. Next, in step Pa2, the conductive particles 8b are mounted on the adhesive elements 8a provided on the FPC board 103, that is, only on the electrical connection regions. The conductive particles 8b are mounted in a number sufficient for electrical connection. The conductive particles 8b are ejected from the nozzle 13b as a droplet material, and are applied only to necessary areas. Next, in step Pa3, the driver IC 6 according to the present invention is mounted so as to cover the adhesive element 8a to which the conductive particles 8b have been mounted. Specifically, the driver IC 6 is temporarily fixed so that the individual outputs of the driver IC 6, that is, the bumps 6a and 6b correspond to the electrode wirings 7b provided on the FPC board 103. Next, in step Pa4, the driver IC 6 is thermocompression-bonded to the FPC board 103 by the heated head. By this step Pa4, the adhesive element 8a, which is a thermosetting resin, is cured, and the electrode wiring 7b disposed on the FPC board 103 and the driver IC 6 are electrically connected through the conductive particles 8b. The pressure at this time is not particularly limited as long as electrical conduction can be secured and the electrode wiring 7b and the driver IC 6 are not damaged. Next, in step Pa5, the connection region is molded to prevent the connection region from being defective due to moisture. As the molding agent, for example, a photocurable resin or a silicone resin is used.
[0046]
Next, a bonding step Pb of the FPC board 103 and the liquid crystal panel 102 is performed. The electrode wiring portion of the liquid crystal panel 102 has a thermocompression bonding portion 105 for thermocompression bonding the FPC board 103. Therefore, in this step Pb1, the ACF 5a is mounted between the electrodes of the liquid crystal panel 102 and the FPC board 103. Next, in step Pb2, the thermocompression bonding head is pressed against the thermocompression bonding section 105. Thus, the thermocompression bonding section 105 is pressurized and heated, and the FPC board 103 and the liquid crystal panel 102 are joined by the ACF 5a. Thus, the conductive particles in the ACF 5a electrically connect the respective electrodes.
[0047]
In the mounting step Pc of the PCB substrate 104 by the SMT method, solder printing is performed in the step Pc1. In this solder printing, a metal mask is placed on the surface of the PCB substrate 104, and the paste solder 11 is placed on the metal mask. Then, the solder 11 is extended by moving the squeegee or the like in parallel, and the solder 11 having the mask pattern of the metal mask is placed on the electrode terminals 9 b of the PCB substrate 104. After that, by separating the metal mask from the PCB substrate 104, the solder 11 is printed on the electrode terminals 9b. As described above, the solder 11 is placed on the electrode terminals 9b of the PCB substrate 104. Next, in step Pc2, mounting processing of the chip component 10 is performed on the PCB substrate 104. On this chip component 10, for example, an electrolytic capacitor or the like is mounted. Next, in step Pc3, a reflow process is performed. This is a process of transporting the PCB substrate 104 on which the chip components 10 are mounted into a reflow furnace, and supplying hot air to the side of the PCB substrate 104 on which the chip components 10 are mounted in the reflow furnace. Thereby, the solder 11 is melted and the plurality of chip components 10 are collectively soldered to the plurality of terminals 9b.
[0048]
Next, in step Pd, a bonding step between the FPC board 103 bonded to the liquid crystal panel 102 and the PCB board 104 is performed. In step Pd1, the ACF 5b is mounted between the electrodes of the FPC board 103 and the PCB board 104. Next, in the process Pd2, the heated head is pressed against the thermocompression bonding region 106. Thereby, the thermocompression bonding section 106 is pressed and heated, and the FPC board 103 and the PCB board 104 are joined by the ACF 5b. In short, the conductive particles in the ACF 5b electrically connect the respective electrodes.
[0049]
By the above mounting process, the liquid crystal display device shown in FIG. 1 having the mounting substrate on which the driver IC according to the present invention is mounted can be manufactured.
[0050]
Therefore, according to the present invention, the mounting of the driver IC 6, that is, the electronic component including the bumps 6 a and 6 b having the protruding portions, can accurately capture the conductive particles mounted to the minimum necessary, and Since a short circuit between the bumps does not occur, highly reliable electrical connection can be achieved. In addition, since the conductive particles can be prevented from being arranged in a region not involved in the electrical connection, it is possible to cope with a narrow pitch of the mounting substrate.
[0051]
(Manufacturing method example 2)
FIG. 7 is a flowchart of the mounting board according to the present embodiment.
[0052]
In Production Method Example 2, the adhesive layer is mounted on the mounting substrate using an adhesive sheet containing no conductive particles, for example, an NCF (Non Conductive Film), and the conductive particles discharge droplet material from a nozzle. It is characterized by using the method of
[0053]
In step Pe1, an NCF is mounted on the FPC board 103. Since the NCF is an adhesive sheet, it is mounted not only in the electrical connection area but also in the entire area where components to be mounted are mounted. As the material of the NCF, for example, an epoxy resin of a thermosetting resin can be used. Next, in step Pe2, conductive particles are mounted on the NCF provided on the FPC board 103 and in the electrical connection region. The number of conductive particles to be mounted is sufficient for electrical connection. The conductive particles are ejected from the nozzle as a droplet material, and are applied only to necessary areas. Next, in step Pe3, the driver IC 6 according to the present invention is mounted so as to cover the NCF on which the conductive particles are mounted. Specifically, the driver IC 6 is temporarily fixed so that the individual outputs of the driver IC 6, that is, the bumps 6a and 6b correspond to the electrode wirings 7b provided on the FPC board 103. Next, in step Pe4, the driver IC 6 is thermocompression-bonded to the FPC board 103 by the heated head. In this step Pe4, the NCF, which is a thermosetting resin, is cured, and the electrode wiring 7b disposed on the FPC board 103 and the driver IC 6 are electrically connected through the conductive particles. The pressure at this time is not particularly limited as long as electrical conduction can be secured and the electrode wiring 7b and the driver IC 6 are not damaged. Next, in step Pe5, the connection region is molded to prevent the connection region from being defective due to moisture. As the molding agent, for example, a photocurable resin or a silicone resin is used.
[0054]
Next, a bonding step Pb of the FPC board 103 and the liquid crystal panel 102 is performed.
[0055]
Then, in the mounting process Pc, the mounting of the PCB substrate 104 by the SMT method is performed.
[0056]
Further, in the step Pd, a bonding step of the FPC board 103 bonded to the liquid crystal panel 102 and the PCB board 104 is performed.
[0057]
Through the above mounting process, the liquid crystal display device shown in FIG. 1 having the mounting substrate on which the driver IC 6 according to the present invention is mounted can be manufactured.
[0058]
Therefore, according to the present invention, the mounting of the driver IC 6, that is, the electronic component including the bumps 6 a and 6 b having the protruding portions, can accurately capture the conductive particles mounted to the minimum necessary, and Since a short circuit between the bumps does not occur, highly reliable electrical connection can be achieved. In addition, since the conductive particles can be prevented from being arranged in a region not involved in the electrical connection, it is possible to cope with a narrow pitch of the mounting substrate.
[0059]
(Production method example 3)
FIG. 8 is a flowchart of the mounting board according to the present embodiment.
[0060]
In Production Method Example 3, the adhesive layer is coated using a screen plate, a dispenser, or a brush using an adhesive containing no conductive particles, for example, NCP (Non Conductive Paste) in which NCF is made into a paste. The method is characterized in that a method is used in which the conductive particles are applied to a mounting substrate by a method or the like and a droplet material is discharged from a nozzle.
[0061]
In step Pf1, NCP is applied to the FPC board 103. The NCP is applied not only to the electrical connection area but also to the entire area where components to be mounted are mounted. The NCP is applied by using, for example, a screen plate, a dispenser or a brush. As the material of the NCP, for example, an epoxy resin of a thermosetting resin can be used. Next, in step Pf2, conductive particles are mounted on the NCP applied to the FPC board 103 and in the electrical connection region. The number of conductive particles to be mounted is sufficient for electrical connection. The conductive particles are ejected from the nozzle as a droplet material, and are applied only to necessary areas. Next, in step Pf3, the driver IC 6 according to the present invention is mounted so as to cover the NCP on which the conductive particles are mounted. Specifically, the driver IC 6 is temporarily fixed so that the individual outputs of the driver 6, that is, the bumps 6a and 6b correspond to the electrode wirings 7b provided on the FPC board 103. Next, in step Pf4, the driver 6 is thermocompression-bonded to the FPC board 103 by the heated head. In this step Pf4, the NCP which is a thermosetting resin is cured, and the electrode wiring 7b arranged on the FPC board 103 and the driver IC 6 are electrically connected through the conductive particles. The pressure at this time is not particularly limited as long as electrical conduction can be secured and the electrode wiring 7b and the driver IC 6 are not damaged. Next, in Step Pf5, the connection region is molded to prevent the connection region from being defective due to moisture. As the molding material, for example, a photocurable resin, a silicone resin, or the like is used.
[0062]
Next, a bonding step Pb of the FPC board 103 and the liquid crystal panel 102 is performed.
[0063]
Then, in the mounting process Pc, the mounting of the PCB substrate 104 by the SMT method is performed.
[0064]
Further, in step Pd, a joint portion between the FPC board 103 joined to the liquid crystal panel 102 and the PCB board 104 is performed.
[0065]
Through the above mounting process, the liquid crystal display device shown in FIG. 1 having the mounting substrate on which the driver IC 6 according to the present invention is mounted can be manufactured.
[0066]
Therefore, according to the present invention, the mounting of the driver IC 6, that is, the electronic component including the bumps 6 a and 6 b having the protruding portions, can accurately capture the conductive particles mounted to the minimum necessary, and Since a short circuit between the bumps does not occur, highly reliable electrical connection can be achieved. In addition, since the conductive particles can be prevented from being arranged in a region not involved in the electrical connection, it is possible to cope with a narrow pitch of the mounting substrate.
[0067]
[Other embodiments]
As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and can be variously modified within the scope of the invention described in the claims.
[0068]
The board on which the driver IC 6 is mounted is not limited to the FPC board, but may be implemented on, for example, a glass board.
[0069]
[Manufacturing method of liquid crystal display device]
Next, an example of a method for manufacturing the liquid crystal display device 100 shown in FIG. 1 will be described with reference to FIG.
[0070]
First, in step A1 of FIG. 9, a first electrode that is a transparent electrode 2a is formed on a large-sized first substrate 1a that is an insulating substrate made of glass or plastic. Specifically, terminals and the like (not shown) are formed by a known pattern forming method using ITO as a material, for example, a photolithography method.
[0071]
Next, in step A2, an alignment film made of a polyimide resin or the like (not shown) is formed on the transparent electrode film 2a, and in step A3, a rubbing treatment or the like is performed.
[0072]
On the other hand, in step B1, the transparent electrode film 2b is formed on the large-sized second substrate 1b by the same method. Further, in step B2, an alignment film (not shown) is formed on the transparent electrode film 2b, and in step B3, a rubbing process or the like is performed.
[0073]
Further, in step A4, a sealing material is formed on the first substrate using, for example, epoxy resin or the like on the substrate 1a, and in step A5, the spacers are dispersed.
[0074]
After the first substrate 1a and the second substrate 1b thus formed are manufactured, in a step C1, the first substrate 1a and the second substrate 1b are overlapped with each other with a sealing material interposed therebetween, and further pressed. That is, both substrates are bonded to each other by pressing under heating. By this bonding, a large-sized structure (that is, a mother substrate) including a plurality of liquid crystal cells 101 in FIG. 1 is formed.
[0075]
After the mother substrate is manufactured as described above, the first break step is performed in step C2. As a result, a plurality of medium-sized panel structures including a plurality of liquid crystal panel portions in which a liquid crystal injection port (not shown) is exposed to the outside, that is, a plurality of so-called strip-shaped medium-sized panel structures are cut out.
[0076]
Then, in step C3, the liquid crystal is injected into the inside of the liquid crystal panel portion through a liquid crystal injection port (not shown), and after the injection is completed, the liquid crystal injection port is sealed with a resin to form the liquid crystal layer 4.
[0077]
Further, in step C4, a second break step is performed on the medium-sized panel structure. Specifically, the substrate 1a and the substrate 1b constituting the medium-sized panel structure are cut, whereby the liquid crystal cells 101 in FIG. 1 are separated one by one.
[0078]
Thereafter, in step C5, the wiring terminal 7a of the FPC board 103 on which the driver IC 6 according to the present invention is mounted and the wiring terminal 2b of the liquid crystal cell 101 are mounted via the ACF 5a. Further, the wiring terminal 7c of the FPC board 103 and the wiring terminal 9a of the PCB board 104 are mounted via the ACF 5b.
[0079]
Next, in steps C6 and C7, a retardation plate, polarizing plates 3a, 3b, and the like are mounted on the outside of the first substrate 1a and the second substrate 1b of the mounted liquid crystal cell 101 as necessary. The liquid crystal display device 100 shown in FIG. 1 is completed.
[0080]
[Electronics]
FIG. 10 is a schematic configuration diagram illustrating the overall configuration of the present embodiment. The electronic device shown here includes the above-described liquid crystal display device 100 and control means 110 for controlling the same. Here, the liquid crystal display device 100 is conceptually divided into a panel structure 100A and a drive circuit 100B including a semiconductor IC or the like. Further, the control unit 110 includes a display information output source 111, a display information processing circuit 112, a power supply circuit 113, and a timing generator 114.
[0081]
The display information output source 111 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit for synchronizing and outputting a digital image signal. And is configured to supply display information to the display information processing circuit 112 in the form of an image signal in a predetermined format based on various clock signals generated by the timing generator 114.
[0082]
The display information processing circuit 112 includes well-known various circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit. Is supplied to the drive circuit 100B together with the clock signal CLK. The driving circuit 100B includes a scanning line driving circuit, a data line driving circuit, and an inspection circuit. The power supply circuit 113 supplies a predetermined voltage to each of the above-described components.
[0083]
Next, a specific example of an electronic apparatus to which the liquid crystal display device according to the present invention can be applied will be described with reference to FIG.
[0084]
First, an example in which the liquid crystal display device according to the present invention is applied to a display unit of a portable personal computer (so-called notebook computer) will be described. FIG. 11A is a perspective view showing the configuration of the personal computer. As shown in the figure, the personal computer 210 includes a main body 212 provided with a keyboard 211 and a display 213 to which the liquid crystal display device according to the present invention is applied.
[0085]
Subsequently, an example in which the liquid crystal display device according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 11B is a perspective view showing the configuration of the mobile phone. As shown in the figure, the mobile phone 220 includes a plurality of operation buttons 221, an earpiece 222, a mouthpiece 223, and a display unit 224 to which the liquid crystal display device according to the invention is applied.
[0086]
Note that, as electronic devices to which the liquid crystal display panel according to the present invention can be applied, in addition to the personal computer shown in FIG. 11A and the mobile phone shown in FIG. A video tape recorder, a car navigation device, a pager, an electronic organizer, a calculator, a word processor, a workstation, a videophone, a POS terminal, a digital still camera, and the like, which are directly viewed from a monitor.
[0087]
[Modification]
Further, the electro-optical device of the present invention is not limited to a passive matrix type liquid crystal display panel, but also includes an active matrix type liquid crystal display panel (for example, a liquid crystal display panel having a TFT (thin film transistor) or a TFD (thin film diode) as a switching element). ) Can be similarly applied. The present invention is applicable not only to liquid crystal display panels but also to various electro-optical devices such as electroluminescence devices, organic electroluminescence devices, plasma display devices, electrophoretic display devices, and field emission displays (field emission display devices). The same can be applied.
[Brief description of the drawings]
FIG. 1 is a plan view of a liquid crystal display device on which a driver IC according to the present invention is mounted.
FIG. 2 is a sectional view of a liquid crystal display device on which a driver IC according to the present invention is mounted.
FIG. 3A is a perspective view of a driver IC according to an embodiment of the present invention.
FIG. 3B is a side view of the bump of the driver IC according to the embodiment of the present invention.
(C) is a side view of the bump of the driver IC according to the embodiment of the present invention.
FIG. 4A is a perspective view of a driver IC according to an embodiment of the present invention.
(B) is a perspective view of a bump of the driver IC according to the embodiment of the present invention.
(C) is a sectional view of a bump of the driver IC according to the embodiment of the present invention.
FIG. 5 shows a method of manufacturing a mounting board on which a driver IC according to the present invention is mounted.
FIG. 6 is a diagram schematically showing a main process of the process shown in FIG. 5;
FIG. 7 shows a method of manufacturing a mounting board on which a driver IC according to the present invention is mounted.
FIG. 8 shows a method of manufacturing a mounting board on which a driver IC according to the present invention is mounted.
FIG. 9 is a flowchart showing a method of manufacturing the liquid crystal display device shown in FIG.
FIG. 10 illustrates a configuration of an electronic device using a liquid crystal display device to which the present invention is applied.
FIG. 11 illustrates an example of an electronic apparatus including a liquid crystal display device to which the present invention is applied.
[Explanation of symbols]
1a First substrate
1b Second substrate
2a 2b Electrode wiring (transparent electrode film)
33a 3b, polarizing plate
4 Liquid crystal layer
5a 5b ACF
6 Driver IC
7a 7b 7c Electrode wiring
8a, adhesive element
8b, conductive particles
9a 9b electrode wiring
10 Chip components
11 Solder
13a 13b nozzle
100 liquid crystal display
103 FPC board
104 PCB board

Claims (10)

An electronic component electrically connected to the plurality of electrode wirings by a bonding element with respect to a substrate provided with a plurality of electrode wirings, the electronic component having a protrusion at a connection portion with the substrate, The component has a bump at the connecting portion, the projecting portion projects from at least an end of the bump toward the substrate, and the projecting portion is provided at least at an edge where the bumps are adjacent to each other. An electronic component mounting method,
Arranging an adhesive layer on the electrode wiring provided on the substrate,
Arranging conductive particles on the electrode wiring provided on the substrate,
Curing the adhesive layer while applying pressure to the substrate and the electronic component, and electrically connecting the substrate and the electronic component,
The method of mounting an electronic component, wherein the step of disposing the conductive particles comprises disposing the conductive particles by discharging a droplet material from a nozzle. The method of claim 1, wherein the height of the protrusion has a value of 3 μm to 5 μm from an end of the bump. The mounting of the electronic component according to claim 1, wherein, in the step of disposing the conductive particles, the conductive particles are disposed on the adhesive layer disposed on the electrode wiring. 4. Method. The method according to claim 1, wherein the conductive particles are metal particles. The method of mounting an electronic component according to claim 1, wherein the conductive particles are covered with a film having an electrically insulating property. The method according to claim 1, wherein a surface of the conductive particle is a metal-coated particle. A mounting board for electronic components, which is manufactured by the electronic component mounting method according to claim 1. An electro-optical device, comprising: the electronic component mounting board according to claim 7; and a panel having an electro-optical material. 9. The electro-optical device according to claim 8, wherein the panel having the electro-optical material is a liquid crystal panel, and the electronic component is an IC for driving the liquid crystal panel. An electronic apparatus comprising the electro-optical device according to claim 9 as a display unit.

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