JP2008244255A - Thermocompression bonding tool and thermocompression bonding device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermocompression bonding tool capable of accurately positioning works to be bonded with each other at all times by image recognition and appropriately thermocompression-bonding them, and a thermocompression bonding device using the same. <P>SOLUTION: An FPC 3 is sucked to the press contact surface 121 of the thermocompression bonding tool 1 by a vacuum suction mechanism, a CCD camera 7 is arranged through a liquid crystal display panel 4 mounted on a main table 6 facing the irradiation port of an optical fiber 16 built in the thermocompression bonding tool 1, and an optical fiber 8 for back surface illumination for irradiating an alignment mark formed on the glass substrate 41 of the liquid crystal display panel 4 is arranged side by side with the CCD camera 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermocompression bonding tool suitable for thermocompression bonding between light transmissive workpieces and a thermocompression bonding apparatus using the thermocompression bonding tool.

  Conventionally, a flexible wiring board (hereinafter referred to as FPC: Flexible Printed Circuit) is used as a connector member for electrically connecting a liquid crystal display panel and an external circuit board. When this FPC is conductively bonded to the wiring circuit of the glass substrate of the liquid crystal display panel, the connection terminals are conductively connected to each other via an anisotropic conductive adhesive (hereinafter referred to as ACF: Anisotropic Conductive Film).

  ACF is a conductive joining member obtained by dispersing and mixing conductive particles having an average particle size of about 5 μm in a thermosetting binder resin such as an epoxy resin. Therefore, a thermocompression bonding tool that can apply pressure while heating is used when the APC is used to conductively connect the wirings of the FPC and the liquid crystal display panel.

When the FPC is conductively bonded to the glass substrate of the liquid crystal display panel using a thermocompression bonding tool, it is necessary to accurately superimpose the corresponding connection terminals of both wirings. There is an alignment method by image recognition using a CCD (Charge-Coupled Device) camera as shown in FIG.
JP-A-9-219584

  In the case of the alignment method based on the image recognition described above, the CCD camera and its imaging illumination means are arranged on the opposite side (back side) of the thermocompression bonding tool with the FPC as a work and the liquid crystal display panel interposed therebetween. This is because the thermocompression bonding tool itself is relatively large with respect to the joint area because the thermocompression bonding tool itself has a built-in intake pipe for vacuum suction of the heater and workpiece, and recognizes images from CCD cameras and lighting fixtures. This is because it is difficult to secure an appropriate space for arranging the equipment.

  When both the illumination tool and the CCD camera are arranged on the opposite side of the thermocompression bonding tool, the image captured by the CCD camera is an image by reflected illumination. For this reason, the irradiation mark is diffusely reflected or diffusely reflected due to the surface condition of the alignment mark formed of a metal film such as copper, which is the same material as the wiring pattern, or the curvature of the FPC itself, thereby reducing the visibility of the alignment mark image. As a result, the image recognition is hindered and accurate alignment cannot be performed.

  An object of the present invention is to provide a thermocompression bonding tool and a thermocompression bonding apparatus using the thermocompression bonding tool capable of always accurately aligning workpieces to be crimped by image recognition and performing proper thermocompression bonding.

  A thermocompression bonding tool according to claim 1 of the present invention includes a plane that is pressed against a workpiece, a heater that heats the plane to a predetermined temperature, and a light guide that guides illumination light to an alignment mark installed on the workpiece. And an intake pipe for vacuum-sucking the work on the plane, and is driven to move forward and backward with respect to the work.

  The thermocompression bonding tool described in claim 2 is the thermocompression bonding tool according to claim 1, wherein the light guide is an optical fiber bundle formed by bundling optical fibers made of ceramics.

  The thermocompression bonding tool according to claim 3 is the thermocompression bonding tool according to claim 1 or 2, wherein the work holding unit provided with the intake pipe, and the work illumination unit provided with the light guide. However, it is divided so that attachment or detachment is possible.

  The thermocompression bonding apparatus according to claim 4 of the present invention is held by suction with the thermocompression bonding tool according to claim 1, a light source that emits light irradiated through the light guide, and the thermocompression bonding tool. A support base made of a light-transmitting material for supporting a work to be bonded to which the work is thermocompression-bonded, and placed on the opposite side of the support base from the thermocompression-bonding tool and emitted from the light guide body of the thermocompression-bonding tool An image recognition camera that irradiates one or both of the alignment marks corresponding to each other of the workpiece and the workpiece to be bonded and receives the light transmitted through the support base and images the alignment marks; It is characterized by having.

  According to a fifth aspect of the present invention, there is provided a thermocompression bonding apparatus according to the fourth aspect, wherein the thermocompression bonding apparatus according to the fourth aspect further includes a back irradiation unit that is disposed on the opposite side of the support base from the thermocompression bonding tool and that irradiates the alignment mark. It is characterized by having.

  According to the thermocompression bonding tool of the present invention and the thermocompression bonding apparatus using the same, it is possible to perform workpiece alignment by accurate image recognition. As a result, the workpieces to be crimped are always accurately aligned and appropriate. It becomes possible to thermo-compression to.

  1 (a) and 1 (b) are process explanatory views showing the steps of a thermocompression bonding apparatus as an embodiment of the present invention and a thermocompression bonding process using the same, respectively, and FIGS. 2 (a) and 2 (b) are respectively described above. The front view and bottom view showing the thermocompression bonding tool in the thermocompression bonding apparatus, and FIGS. 3A and 3B are respectively explanatory views showing the work to be thermocompression bonded and the work to be bonded in the thermocompression bonding step.

  As shown in FIGS. 1A and 1B, the thermocompression bonding apparatus of the present embodiment includes a thermocompression bonding tool 1, a driving mechanism 2 that drives the thermocompression bonding tool 1, FPC 3 as a work, and each table that supports a liquid crystal display panel 4. 5, 6, a CCD camera 7, a back side illumination tool 8, and the like.

  First, the FPC 3 and the liquid crystal display panel 4 that are thermocompression bonded by the thermocompression bonding tool 1 will be described with reference to FIGS. FIGS. 3A and 3B are plan views showing surfaces to be joined together.

  As shown in FIG. 3A, the FPC 3 of the work is formed by using a translucent flexible resin film having excellent heat resistance such as polyimide resin as a base sheet 31 and applying a conductive film on the surface thereof, and then performing photolithography. Then, the wiring pattern 32 is formed by patterning, and the insulating protective film 33 is deposited except for the tip portion which is the connection terminal 321 of the wiring pattern 32. A pair of alignment marks 34 and 34 are simultaneously formed of the same conductive material as that of the wiring pattern 32 on both sides of the terminal array portion in which the connection terminals 321 are arranged in parallel. Note that the wiring pattern 32 and the pair of alignment marks 34, 34 of the present embodiment are made of copper.

  On the other hand, in the liquid crystal display panel 4 of the work to be bonded, liquid crystal (not shown) is sealed between a pair of glass substrates 41 and 42 (see FIG. 1B). As shown in FIG. 3B, a driver chip 43 for driving liquid crystal is mounted on the protruding end portion of the glass substrate 42 by COG (Chip On Glass). Each connection terminal 441 of the input wiring pattern 44 for inputting is arranged in parallel along the edge of the protruding end. The connection terminals 441 of the input wiring pattern 44 and the connection terminals 321 of the FPC 3 are juxtaposed at equal pitches, and the corresponding connection terminals are conductively connected. A pair of alignment marks 45 is formed on both sides of the array portion where the connection terminals 441 are arranged in correspondence with the alignment mark 34 on the FPC 3 side. These alignment marks 45, 45 are simultaneously formed with ITO (indium tin oxide) made of the same material as the wiring pattern 44.

  As shown in FIGS. 2A and 2B, the thermocompression bonding tool 1 is formed along the longitudinal direction of the main body 11 that forms a rectangular parallelepiped and the center of the width of the surface of the main body 11 that is advanced toward the workpiece. The pressing head 12 is provided with a convex shape. The front end surface 121 of the pressing head 12 serves as a pressure contact surface that is in pressure contact with the FPC 3, and as shown by a two-dot chain line in FIG. 3A, a terminal array portion in which the connection terminals 321 in the FPC 3 are arranged in parallel and both sides thereof. Both corner portions where the alignment marks 34 and 34 are disposed have an area that can cover an appropriate length of margin on both sides.

  By forming the pressure contact surface 121 of the pressing head 12 in a large area as described above, the entire end portion where the connection terminals 321 of the FPC 3 are juxtaposed can be reliably thermocompression bonded to the corresponding portion of the liquid crystal display panel 4. it can. That is, as shown by the two-dot chain line in FIGS. 3A and 3B, the ACF 9 as the conductive connection member of both the connection terminals 321 and 441 is not only the array portion of the connection terminal 321 but also the alignment marks on both sides thereof. 34, 34 is arranged over an area including both corners, that is, an area covering almost the entire end of the FPC 3, and the entire ACF 9 is heated and pressed by the large-area pressure contact surface 121 with allowance for allowance. As a result, all the ACFs including the softened and protruding parts are surely cured, and the entire end of the FPC 3 is securely bonded via the ACF 9 without generating a floating edge without being bonded. Be joined. Thereby, the reliability of the thermocompression bonding of the FPC 3 and the liquid crystal display panel 4 is improved.

  Returning to FIG. 2, a pair of heaters 13 and 13 are embedded in the main body 11 of the thermocompression bonding tool 1 along both longitudinal sides thereof. Further, an intake pipe 14 for adsorbing the FPC 4 as a work by vacuum suction is disposed in the pressing head 12. In the present embodiment, three intake pipes 14 are provided, and the respective suction ports 141 are arranged at equal intervals along the longitudinal direction at the center of the width of the pressure contact surface 121 of the pressing head 12. These three intake pipes 14 are drawn out of the main body 11 together into a single tube 15 and connected to a vacuum pump (not shown).

  Further, in the thermocompression bonding tool 1, a pair of optical fibers 16 and 16 are installed at both ends in the longitudinal direction as a light guide for front side illumination light. Each optical fiber 16 is formed by bundling a plurality of ceramic optical fibers in a bundle shape, and is embedded perpendicularly to the pressure contact surface 121 in the center of the width at the end in the longitudinal direction of the thermocompression bonding tool 1. Yes. Accordingly, the irradiation ports 161 opened in the pressure contact surfaces 121 of the optical fibers 16 are respectively disposed at both ends of the pressure contact surfaces 121 across the row of the suction ports 141 of the intake pipe 14.

  Each optical fiber 16 is drawn out of the thermocompression bonding tool 1, and a light source lamp 18 is arranged oppositely to each light incident port at the leading end of the drawing portion via a condenser lens 17, as shown in FIG. ing.

  In FIG. 1, the thermocompression bonding tool 1 configured as described above is driven by a drive mechanism 2 so that an X axis and a Y axis (see FIG. 2) parallel to the pressure contact surface 121 and a Z axis perpendicular to them are orthogonal to each other 3. It is reciprocated linearly in the direction.

  The other end portion of the FPC 3 as a work having one end portion sucked and held by the thermocompression bonding tool 1 is supported by the sub-table 5. The sub table 5 is moved up and down in synchronization with the up and down movement of the thermocompression bonding tool 1 in the Z-axis direction by a drive mechanism (not shown).

  A liquid crystal display panel 4 as a work to be bonded to which the FPC 3 is thermocompression bonded is placed on a main table 6. The main table 6 is reciprocated linearly in the XY axis direction by a drive mechanism (not shown) and reciprocally rotated about a rotation axis (not shown) standing in parallel with the Z axis. And the shelf part 61 of the main table 6 that supports the protruding end part to which the FPC 3 of the liquid crystal display panel 4 is thermocompression bonded is formed of a transparent material such as glass and the like as shown in FIG. It is configured to advance and retract to the indicated thermocompression bonding position.

  On the opposite side of the thermocompression bonding tool 1 across the main table 6, a pair of image recognition CCD cameras 7 are respectively arranged corresponding to the optical fibers 16. Each CCD camera 7 is installed in an arrangement in which its optical axis substantially overlaps with the extension of the optical axis of the corresponding optical fiber 16, that is, in an opposed arrangement.

  An optical fiber 8 for back lighting is installed on the side of the CCD camera 7. The back side irradiating optical fiber 8 is provided on the alignment mark 45 (see FIG. 3B) of the liquid crystal display panel 4 supported by the shelf 61 that has advanced the light emitted from the light source (not shown) to the thermocompression bonding position. The angle of the optical axis is set so that the light can be irradiated.

  Next, the thermocompression bonding operation of the FPC 3 to the liquid crystal display panel 4 by the thermocompression bonding apparatus configured as described above will be described.

  First, the thermocompression bonding tool 1 is moved to the yard where the FPC is stocked and the FPC 3 to be thermocompression bonded is held by suction on the head front end surface 121 and then stopped at the thermocompression bonding station shown in FIG. . At this time, the liquid crystal display panel 4 waits at a retracted position outside the figure without advancing to the thermocompression bonding position below the thermocompression bonding tool 1.

  Under the above-described state, the alignment mark 34 corresponding to the FPC 3 is irradiated from the front side (the back side of the FPC 3) through the pair of front irradiation optical fibers 16 built in the thermocompression bonding tool 1. At this time, since the irradiation port 161 of the front-facing optical fiber 16 is sufficiently larger than the alignment mark 34 as shown in FIG. 3A, even if the FPC 3 is not accurately aligned, The entire alignment mark 34 can be stably irradiated with sufficient light.

  Then, the corresponding alignment mark 34 is imaged by the pair of CCD cameras 7. When the alignment mark 34 is imaged, the CCD camera 7 captures a shadow image by the transmitted light from the optical fiber 16 on the front side. Therefore, the alignment mark 34 is always visible regardless of the surface state of the alignment mark 34 and the warp of the FPC itself. A good alignment mark image can be captured, and as a result, the position of the alignment mark 34 can be stably and accurately recognized.

  Next, the liquid crystal display panel 4 placed by rotating the main table 6 is positioned at the thermocompression bonding position shown in FIG. An ACF 9 is arranged at the protruding end portion of one glass substrate 51 of the liquid crystal display panel 4 advanced to the bonding position so as to correspond to the connection terminal array portion of the electrode wiring. In this case, as shown in FIG. 3B, the ACF 9 is arranged over an area including not only the connection terminal array portion 42 but also the alignment marks 45 on both sides thereof.

  Next, light is irradiated toward the alignment mark 45 (see FIG. 3B) of the liquid crystal display panel 4 that is positioned at the thermocompression bonding position through the optical fiber 8 for back illumination. At this time, the irradiation light from the front illumination optical fiber 16 is also transmitted through the ACF 9 to a certain extent because the thickness of the ACF 9 is about 40 μm and becomes illumination light of the alignment mark 45. Accordingly, in imaging of the alignment mark 45 on the liquid crystal display panel 4 side, the alignment mark 45 formed of ITO is formed by adding the transmitted illumination from the front illumination optical fiber 16 to the reflected illumination from the back illumination optical fiber 8. The optimal illumination balance can be obtained. As a result, an image with good visibility of the alignment mark 45 made of ITO, which is difficult to obtain with only reflected illumination, can be picked up by the CCD camera 7, and accurate image recognition of the position of the liquid crystal display panel 4 can be performed.

  Each position data obtained by image recognition of the alignment marks 34 and 45 is sent to an arithmetic control unit (not shown) to calculate the amount of deviation between the two, and the main table 6 and the thermocompression bonding tool to eliminate this amount of deviation. Any one or both of 1 are adjusted and moved in the XY axis direction.

  When the alignment between the alignment marks 34 and 45 is eliminated and the corresponding connecting terminals are accurately overlapped with each other, the thermocompression bonding tool 1 is set together with the sub table 5 as shown in FIG. The FPC 3 is lowered by the stroke, and the FPC 3 is pressurized and bonded to the liquid crystal display panel 4 through the ACF 9 while being subjected to thermocompression bonding. Thereby, each connection terminal 321 of the connection terminal array part 32 of the FPC 3 shown in FIGS. 3A and 3B and the corresponding connection terminal 441 of the connection terminal array part 44 of the liquid crystal display panel 4 are connected to each other in the ACF 9. The conductive connection is accurately made through the conductive particles.

  In this thermocompression bonding, the body 11 of the thermocompression bonding tool 1 has a temperature of 200 due to the heat generating action of the heater 13 for heating the ACF 9 to 180 to 190 ° C. where the thermosetting binder resin is sufficiently cured. Although it rises to a high temperature of ˜300 ° C., each fiber of the optical fiber 16 is made of ceramics having excellent heat resistance, so that it does not thermally deteriorate.

  As described above, according to the thermocompression bonding tool of the present embodiment and the thermocompression bonding apparatus using the same, since the optical fiber 16 that irradiates the alignment mark 34 is built in the thermocompression bonding tool 1 that holds the FPC 3 by suction. The CCD camera 7 that images the mark 34 and the optical fiber 16 of the illuminating means are arranged opposite to each other with the alignment mark 34 interposed therebetween, and the alignment mark 34 can be imaged as a shadow image by transmitted light. Therefore, an alignment mark image with high visibility is always obtained without being affected by deformations such as the surface state of the alignment mark 34 and warping of the FPC 3, and based on this, the position of the FPC 3 can be accurately recognized. .

  Further, since the optical fiber 8 for back lighting is juxtaposed on the CCD camera 7 side, when the image of the position of the liquid crystal display panel 4 to which the FPC 3 is thermocompression bonded is recognized, as shown in FIG. Can be irradiated with a sufficient amount of light from the back surface without an obstacle. At this time, the light emitted from the optical fiber 16 with a built-in thermocompression bonding tool on the front side and transmitted through the FPC 3 also passes through the ACF 9 to some extent and irradiates the alignment mark 45. Therefore, it is formed of a transparent conductive material such as ITO (indium tin oxide) under a good illumination balance in which the transmitted light from the front side fiber 16 is added to the sufficient reflected light from the optical fiber 8 for back lighting. Even with the alignment mark 45, the CCD camera 7 can always capture an image with good visibility, and based on this, the position of the liquid crystal display panel 4 can be accurately recognized.

  The position based on the alignment mark 34 of the FPC 3 and the position based on the alignment mark 45 of the liquid crystal display panel 4 affect the formation state of the alignment marks 34 and 45, the deformation state of the FPC 3 and the liquid crystal display panel 4, respectively. However, since the image is always recognized accurately, the two can be conductively joined by thermocompression bonding accurately and reliably without causing problems such as poor conduction.

  Next, another embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the component same as the said embodiment, and the description is abbreviate | omitted.

  The thermocompression bonding tool 10 of the present embodiment attaches and detaches the thermocompression bonding tool 1 of the above-described embodiment to a pair of illumination units 101 and 101 each provided with an optical fiber 16 and a workpiece suction unit 102 provided with a suction tube 14. It is divided as possible. In this case, the heater 13 is not divided and is inserted through and inserted into the workpiece adsorption unit 102, and both end portions protruding from both side surfaces are inserted into through holes (not shown) provided in the respective illumination units 101. Other configurations are the same as those in the above embodiment.

  According to the thermocompression bonding tool 10 of the present embodiment configured as described above, even if the type of the liquid crystal display module to be manufactured is changed and the alignment mark position and the length of the connection terminal array portion are different, the thermocompression bonding apparatus as a whole It is possible to respond flexibly only by changing the workpiece suction unit 102 without replacing the workpiece.

In addition, this invention is not limited to said embodiment.
For example, in the thermocompression bonding apparatus of the present invention, it is possible to omit an optical fiber for back lighting. That is, the alignment marks of the workpiece and the workpiece to be bonded are not overlapped with each other, and a sufficient amount of light is irradiated from the thermocompression bonding tool side, or the workpiece to be bonded (the liquid crystal display in the above embodiment) The alignment mark of the panel) is recognized by the transmitted image by the irradiation light from the thermocompression tool side that is not adsorbing the workpiece, and then the workpiece is temporarily retracted and the workpiece is adsorbed to the thermocompression tool. Similarly, in the case of a procedure for recognizing an image with a transmission image by irradiation light from the thermocompression bonding tool side, the optical fiber for back illumination can be omitted.

  In addition, when the present invention is applied to a manufacturing process in which the position of the workpiece with respect to the thermocompression bonding tool is recognized at a station different from the thermocompression bonding station, it is not necessary to move the work to be bonded to the thermocompression bonding station. The mechanism of the main table that supports the crimping work is simplified.

  In addition, the thermocompression bonding tool of the present invention and the thermocompression bonding apparatus using the tool can be widely applied not only to the thermocompression bonding process of the liquid crystal display panel and the FPC but also to a process of thermocompression bonding of light-transmitting workpieces. Of course.

FIG. 5 is a process explanatory view showing a step of thermocompression bonding of an FPC and a liquid crystal display panel according to an embodiment of the present invention for each step, where (a) shows an image recognition step of the position of the FPC, and (b) shows a thermocompression step. Is shown. (A), (b) is the front view and bottom view which respectively show the thermocompression-bonding tool used at the said thermocompression bonding process. (A), (b) is a top view which respectively shows FPC and a liquid crystal display panel which are thermocompression-bonded by the said thermocompression-bonding tool. (A), (b) is the front view and bottom view which respectively show the thermocompression-bonding tool as other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermocompression-bonding tool 11 Main body 12 Pressing head 121 Pressure contact surface (tip surface)
13 Heater 14 Intake pipe 15 Tube 16 Optical fiber (for front irradiation)
2 Drive mechanism 3 FPC
31 Base sheet 32 Wiring pattern 33 Insulating protective film 34 Alignment mark 4 Liquid crystal display panel 41, 42 Glass substrate 43 Driver chip 44 Input wiring pattern 45 Alignment mark 5 Sub-table 6 Main table 61 Shelf 7 CCD camera 8 Optical fiber (Backlight for)
9 ACF
DESCRIPTION OF SYMBOLS 10 Thermocompression bonding tool 101 Illumination part 102 Adsorption part

Claims (5)

A plane pressed against the workpiece,
A heater for heating the plane to a predetermined temperature;
A light guide for guiding illumination light to the alignment mark installed on the workpiece;
An intake pipe for vacuum adsorbing the workpiece on the plane,
A thermocompression bonding tool that is driven to move forward and backward with respect to the workpiece.   The thermocompression bonding tool according to claim 1, wherein the light guide is an optical fiber bundle formed by bundling optical fibers made of ceramics.   The thermocompression bonding according to claim 1 or 2, wherein the work holding part provided with the intake pipe and the work illumination part provided with the light guide are detachably divided. tool. The thermocompression bonding tool according to claim 1;
A light source that emits light irradiated through the light guide;
A support base made of a light-transmitting material for supporting the work to be bonded to which the work held by the thermocompression bonding tool is thermally bonded;
One or both of the alignment marks that are installed on the opposite side of the support base from the thermocompression tool, are emitted from the light guide of the thermocompression tool, and correspond to each other of the work and the work to be crimped. A thermocompression bonding apparatus comprising: an image recognition camera configured to receive the light that has been irradiated and transmitted through the support base and to capture the alignment marks.   The thermocompression bonding apparatus according to claim 4, further comprising a back surface irradiating unit that is installed on the opposite side of the support base from the thermocompression bonding tool and that irradiates the alignment mark.

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