TWI225567B - Printed-circuit board connection method and apparatus - Google Patents

Abstract

Conventionally, the connection between an LCD and a TCP is carried out by heating an ACF at a high temperature of nearly 200 DEG C, and many problems are arising. The present invention is intended to provide a board connection method and apparatus capable of reducing the heating temperature of the ACF. The ACF taken out from a supply reel is irradiated with ultraviolet rays by UV light sources. The UV light sources, spot light sources, apply ultraviolet rays sequentially to desired area portions of the ACF continuously moving relatively with respect to the light sources. The ACF is then bonded to the LCD, and the TCP is connected to the LCD with the ACF disposed therebetween using a heating and pressurizing tool at a heating temperature of 100 DEG C.

Description

1225567 V. Description of the invention (1) Background of the invention 1 · Scope of the invention In the manufacturing method of the liquid crystal display device of the present invention, the connection between the tape carrier package (TCP) and the liquid crystal display panel, and between the TCP and the printed circuit Connections between substrates (PCBs). In particular, the present invention is used to achieve connection under heat and pressure at lower temperatures. 2 · Description of related technology An anisotropic conductive film (A CF) is used to connect a liquid crystal display device with a TCP. The ACF is made of a thermosetting resin, including those in which conductive particles are mixed. The ACF is placed between the liquid crystal display device and the TCP, and heated and pressed at a high temperature of 200 ° C, so that the electrode terminal of the liquid crystal display device and the electrode terminal of the TCP can be electrically connected through the A CF. Fig. 6 is a schematic diagram showing the conditions for changing the thermoplastic resin by heat. In A C F between the electrode terminals to be connected, pressure is applied between the electrode terminals to make conductive particles having a size of several micrometers dispersed in the ACF conductive with each other, so the electrode terminals are electrically connected. At the same time, the thermosetting resin (which is a reactive substance and serves as the base material of the ACF) becomes a highly crosslinked polymer and is cured by heating, thereby achieving a mechanical connection between the electrode terminals. Japanese Unexamined Patent Publication JP-A 59-149327 (1984) has disclosed a technique in which the connection between a liquid crystal display panel and a heat-sealed connector is irradiated with ultraviolet rays to improve the bonding strength. Even in this technique, the connecting portion is heated at a high temperature of 160 to 220 ° C. In this prior art, approximately 200

1225567 V. Description of the invention (2) When heating at a high temperature of ° C, pressurize the ACF. This causes the following problems. (1) Because the heating and pressurizing tool is twisted, the pressure becomes uneven, so stable manufacturing cannot be achieved. (2) In the case where A C F is heated by a heat exchanger, it takes a long time to increase the temperature of the connecting portion because it is in contact with a heating and pressing tool. In particular, in the case where A C F is heated and pressurized at a high temperature, the connection time becomes long, so that the manufacturing efficiency is lowered. (3) Because the temperature of the heating and pressing tool as a heat source is high, it has a negative impact on the structures around the tool. Because of the need to avoid such negative effects, the connection device becomes expensive. Fig. 7 shows a device in which, except for the case of heating and pressing, the A C F is irradiated with ultraviolet rays. Since the structure of this device allows ultraviolet irradiation and heating and pressing to be performed simultaneously, it is difficult to apply ultraviolet rays to the ACF 2 from the heating and pressing tool 6. This limits the direction of UV radiation. In addition, when the LCD 1 series is opaque, ultraviolet irradiation cannot be performed. In addition, even if LCD1 is transparent, when the electrode terminal is made of metal, ultraviolet rays are cut off. Therefore, the electrical connection between the electrode terminal and A C F 2 cannot be sufficiently achieved. SUMMARY OF THE INVENTION The object of the present invention is to provide a method and a device for connecting substrates to each other, wherein the heating temperature when the substrate is connected to the ACF can be reduced. The invention proposes a substrate connection method, which comprises heating a thermosetting resin to which a promoter is added under the action of a promoter, placing the thermosetting resin between the substrates, and connecting the substrates to each other with the thermosetting resin.

1225567 V. Description of the invention (3) According to the present invention, the thermosetting resin is heated and pressurized to connect the substrates to each other. The thermosetting resin includes an accelerator added thereto to promote the thermosetting effect of the thermosetting resin reactive substance, and Placed between these substrates. Therefore, the temperature required to connect the substrates with the thermosetting resin can be reduced, so that thermal distortion of the heating and pressing tool can be avoided, and uneven pressing can be avoided. In addition, the time required for the thermosetting resin to increase the temperature can be shortened, so the time required to connect these substrates can be shortened, and the manufacturing efficiency can be improved. In addition, when using a heated and pressurized tool as a heat source, it is possible to avoid thermal shadows on the surrounding components of the tool. In the present invention, the term substrate is used as a general term, which includes a substrate in a liquid crystal display panel, a TCP type, a tape automatic bending (TAB) tape, a flexible printed circuit (FPC) substrate, a PCB type, and the like. The present invention proposes a substrate connection device using a thermosetting resin with a UV active substance added thereto. The device includes a spotlight light source for applying ultraviolet light to a portion of the thermosetting resin, and changing the UV active substance into an accelerator. Equipment for moving a thermosetting tree / grease relative to a spotlight light source, and equipment for heating a thermosetting resin placed between substrates. According to the present invention, the UV light source for applying ultraviolet rays can be made compact and simple by itself. The invention relates to a substrate connection device using a thermosetting resin (with an UV active substance added thereto), which includes a light source for applying ultraviolet rays to the thermosetting resin, which has a required wavelength, and changes the UV active substance into An accelerator and a device for heating a thermosetting resin placed between substrates.

1225567 V. Description of the invention (4) According to the present invention, ultraviolet rays can be applied to the thermosetting resin by a single irradiation operation, and thus the ultraviolet irradiation time can be shortened. In addition, the period from when both ends of the thermosetting resin are applied to the thermosetting resin including the UV active material from the ultraviolet rays to when the substrates are connected to each other with the thermosetting resin is the same. Therefore, the connection conditions of both ends of the thermosetting resin can be made the same, so that a reliable connection can be obtained. In the substrate connection device of the present invention, the substrate connection device further includes a device for shielding the thermosetting resin and preventing the thermosetting resin from being irradiated by external ultraviolet rays. According to the present invention, it is possible to prevent the thermosetting resin to which the U V active material is added from being irradiated with unnecessary ultraviolet rays. Therefore, these substrates can be connected to each other under an ultraviolet irradiation condition most suitable for including a thermosetting resin to which a UV active material is added. _ _ Brief description of the drawings Other and additional objects, characteristics, and advantages of the present invention can be more clearly understood from the following detailed description and reference to the accompanying drawings, in which: FIG. 1 is a schematic diagram showing a reactive substance for ACF and a UV active substance Fig. 2 is a flowchart illustrating the steps of connecting LCD and TCP according to the present invention; Fig. 3 is a diagram showing a device for applying ultraviolet rays to the ACF of the present invention; Fig. 4 is a diagram showing other devices for applying ultraviolet rays to the ACF of the present invention Figure 5 is a diagram showing another device for applying ultraviolet rays to the ACF of the present invention; Figure 6 is a schematic diagram showing a reactive substance used in the prior art ACF

1225567 V. Thermal change of invention description (5); and FIG. 7 is a diagram showing a device for applying ultraviolet rays to the prior art A C F. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now referring to the drawings, preferred embodiments of the present invention will be described below.

Fig. 1 is a schematic diagram showing the change of a reactive substance and a UV active substance for an ACF. For convenience, the reactive substances and UV active substances in the ACF are each displayed in a single mode. In practice, however, there are several of these substances. In addition to the reactive material and the UV active material, the AC F includes conductive particles not shown in FIG. 1. When irradiated with ultraviolet rays, the UV active substance is changed into an accelerator. In the case where the U V active substance has been changed into an accelerator, it loses its function as a thermosetting accelerator within minutes to tens of minutes. When the function is not lost, the reaction substance and the accelerator are heated at 100 ° C, and the reaction substance becomes a highly crosslinked polymer, so that the substrate can be connected to the ACF. The accelerator becomes a thermosetting accelerator for the reaction substance, so that a sufficient and reliable connection can be obtained even at a heating temperature of 100 ° C. An epoxy resin was used as the thermosetting resin of the ACF substrate. The following are examples of optimum conditions: Intensity of ultraviolet radiation: 10 mW / cm2 to 100 mW / cm2; UV exposure time: 1 second to 10 seconds; <

Heating temperature: 100 ° C; heating and pressing time: 10 seconds to 20 seconds; and pressure: 1.0 Mpa to 5.0 Mpa. Set the optimal conditions so that the peeling strength of the connecting part and A C F-

Page 9 1225567 V. Description of the invention

One of the parameters related to mechanical connection-greater than 500 Newtons / meter, and its connection resistance-parameters related to electrical connection-less than 50 ohms. Referring to FIG. 2, the method of connecting an LCD and TCP with the ACF as shown in FIG. 1 is briefly described as follows. First, the LCD is supplied to a connection device (at step S1). The A CF is adhered to the LCD (step S 2). Under predetermined heating and pressurization conditions-that is, at a heating temperature of 100 ° C, a pressure of 2 MPa, and a heat pressing time of 5 seconds-the AC F is heated and pressurized to temporarily connect, Strengthen the adhesion between Ac F and LCD (step S 3). Next, the ACF partition is removed (step S4). Placing the LCD and TCP electrode terminals on L C D 'with the A C F in between, and mounting the τ c P (step S 5). Predetermined heating and pressurizing conditions-that is, its heating temperature of 100, a t-force of i to 5 MPa, and a heating and pressurizing time of 10 to 20 seconds—heating and pressurizing the ACF 'using the ACF The TCP is permanently connected to the LCD (step s 6). The LCD connected to the TCP is discharged from the connecting device (step S7). In the above steps S1 to S7, it is preferable to irradiate the ACF with ultraviolet rays between steps S1 and S2, between steps S2 and S3, between steps S3 and S4 ', or between steps S4 and S5. ...... The following describes the process of irradiating the ACF with ultraviolet rays between steps S 1 and S 2 of the connection method shown in FIG. 2. FIG. 3 is a diagram showing a first configuration of an apparatus for applying ultraviolet light to ACF 2. FIG. ACF2 ° UV light sources 4a1 and 4a2 are taken out from the supply reel 3 and placed opposite each other, and A C F 2 'is placed therebetween to irradiate the A C F 2 with ultraviolet rays from the U V light source. A spacer (not shown) is adhered to the A C F 2 -side. In the case where the partition is made of a material through which ultraviolet rays cannot pass, ultraviolet rays are applied to

Page 10 1225567 V. Description of the invention (7) A C F 2 side without spacers. The light sources 4 a 1 and 4 a 2-spotlight light sources-continue to apply ultraviolet rays to the required area of the surface of a c F 2 continuously moving relative to the light sources 4 a 1 and 4 a 2. FIG. 4 is a view showing a second structure of a device for applying ultraviolet rays to ACF2. The ACF2 taken out from the supply reel is introduced between two long UV light sources 4a1 and 4a2, which are placed opposite each other. With one irradiation operation, the long UV light sources 4a1 and 4a2 apply ultraviolet rays of a specific wavelength to the ACF2. A c F 2 irradiated with ultraviolet rays by the device shown in FIG. 3 or FIG. 4 is adhered to a required portion of the LCD 'and fixed between the connection portion of the TCP and the LCD 1. Second, the TCP and LCD1 sections are heated and pressurized, and these sections are used to fix the ACF2 in between. Therefore, when pressure is applied at a predetermined pressure, ACF2 between TCP and LCD1 is heated. Therefore, the reactive substance in ACF2 is hardened, and the T C P is mechanically connected to l c D 1. In addition, the device can be constructed as shown in FIG. 5. In this example, the same UV light source 4a as shown in FIG. 3 can be used, and the UV light source 4a is moved relative to the ACF2: UV + is applied to the ACF2. Alternatively, the same UV light source 4b \ 'as shown in Fig. 4 is used to apply ultraviolet rays to ACF2 by a single irradiation operation. The ACF2 is formed by a UV active substance. The UV activity is irradiated with ultraviolet rays, and it becomes 'an accelerator' in time. Therefore, when ACF 2 is stored or stored for a long time, the A c2 is not irradiated. F 2 is preferred. It is possible to construct a device other than 4, using a shielding plate 7 placed around the UV light source to shield ultraviolet rays', so that only the ACF2 part which needs to be irradiated with ultraviolet rays is irradiated. The present invention may be embodied in other specific forms without departing from the basic characteristics of the present invention.

1225567 V. Description of Invention (8). Therefore, these specific examples in all aspects should be regarded as illustrative rather than limiting. The scope of the present invention is defined by the scope of the appended patent application, not by the foregoing description. All changes therein are included in the present invention.

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Claims (1)

1225567 _ Case No. 89107464 Modified month __ VI. Patent application scope 1. A method for connecting substrates, comprising: adding a UV active substance placed between substrates and changed to a heat curing accelerator by ultraviolet irradiation The thermosetting resin is irradiated with ultraviolet rays of 10 m W / cm 2 to 100 m W / cm 2 for 1 second to 10 seconds, so that the above-mentioned UV active material functions as a thermosetting accelerator in a state of 1 The above thermosetting resin is heated and pressurized under a heating temperature of not less than 0 ° C but not more than 160 ° C, and a pressure of 1.0 MPa to 5.0 MPa, thereby connecting these substrates to each other. 2 · A substrate connecting device using a thermosetting resin to which a UV active substance is added, comprising: a spotlight light source for applying ultraviolet light to a portion of the thermosetting resin, and changing the UV active substance into an accelerator; A mobile device for moving the thermosetting resin relative to the light source of the spotlight, and a heating device for heating the thermosetting resin placed between the substrates. 3. A substrate connecting device using a thermosetting resin with a UV active substance added thereto, comprising: a light source for applying ultraviolet rays to the thermosetting resin, which has a desired wavelength, and changes the UV active substance to a single irradiation operation An accelerator; and a heating device for heating a thermosetting resin placed between substrates. 4. The substrate connection device according to item 2 of the scope of patent application, which includes: a device for shielding the thermosetting resin and preventing the thermosetting resin from being irradiated by external ultraviolet rays. 5. The substrate connection device according to item 3 of the scope of patent application, which includes: O: \ 63 \ 63806-930402.ptc Page 14 1225567 O: \ 63 \ 63806-930402.ptc Page 15