JPH05267397A - Tape carrier with protective coating and manufacture thereof - Google Patents

Abstract

PURPOSE:To eliminate the occurance of a crack in a protective coating in the bent part when mounting and to prevent a warp of a substrate from being generated when forming the protective coating. CONSTITUTION:A silicon rubber-formed protective coating 6 is so formed on a conductor pattern 3 formed on an insulating film substrate 1 that only end parts 7 of each conductor may be exposed. Since the conductor pattern 3 is thus coated with silicon rubber which has an excellent heat resistance, an excellent chemical resistance and a good flexibility, except for the part 7 which is required to be exposed, the conductor section can be perfectly protected without any influence by a change due to heat or by the use of chemicals at the time of formation of a tape carrier. When bending the tape carrier, there is no crack in the protective coating section and therefore there is no risk of a short circuit or a disconnection of the conductor. In addition, there is no deviation in the conductor connection position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a semiconductor device (hereinafter referred to as I
The present invention relates to a tape carrier with a protective coating used for mounting (C) on a substrate or for connecting between circuit boards on which ICs and other electronic components are mounted, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal display module currently under development often adopts a TAB mounting method in which a driver IC is mounted on an electrode on a liquid crystal panel using a tape carrier. Along with the increase in size of liquid crystal panels, there is a demand for a multi-terminal connection technology having high density and high reliability between pixel electrodes and drive LSIs. In particular, with the recent increase in the size of liquid crystal display products and the downsizing of screen peripheral technologies, it is required to use a tape carrier incorporated for connecting terminals of liquid crystal pixel electrodes and drive LSIs in a bent state. ing.

[0003]

Conventionally, in this type of tape carrier, in order to prevent the deterioration of the conductor function due to the adhesion of dust and moisture on the surface of the extremely minute conductor pattern formed on the insulating substrate, Normally, a resist of epoxy resin is used as a protective coating on the conductor pattern surface, but the protective coating of epoxy resin is liable to cause cracks when the substrate is bent and used, and therefore dust and moisture are generated from the cracked portions. Not only was it easy to enter, but it also resulted in short circuits and breaks in the conductor.

When a protective coating is formed with an epoxy resin, a heat treatment is required to cure the epoxy resin on an insulating substrate and then to cure the epoxy resin. Volatile components contained in a certain amount of content go out of the system, resulting in large volume contraction during curing and warping of the substrate after curing, resulting in pitch deviation in finely formed leads. , Was a cause of serious trouble in the terminal connection work during mounting.

For this reason, the above-mentioned problems in the tape carrier with the protective coating are solved, and a method of connecting the tape carrier with high dimensional accuracy including the bent portion is described.
Although various proposals have been made, the present situation is that the technology that can sufficiently meet the demand has not been developed yet.

The present invention solves the above-mentioned problems in the conventional tape carrier with a protective coating so that the substrate does not warp during the formation of the protective coating and cracks do not occur during use. It is an object of the present invention to provide a tape carrier with a protective coating in which a transparent protective coating is formed on an insulating substrate.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a tape carrier with a protective coating formed by coating a plurality of conductor patterns formed on an insulating substrate with silicone rubber, and a method for producing the same. It is related to.

[0008]

The operation of the present invention will be described in detail below.

The drawings show an embodiment of the present invention. FIG. 1 is a plan view of a tape carrier before forming a protective coating, wherein 1 is an insulating film substrate and 2 is an insulating film substrate 1. A sprocket hole for feeding the substrate, which is provided penetrating through the insulating film substrate 1, a conductor pattern made of copper provided on the insulating film substrate 1, and 4 and 5 respectively, which are provided through the insulating film substrate 1, These are a device hole and an OLB hole for exposing a part to enable connection with an IC chip or an external circuit.

FIG. 2 is a plan view of a tape carrier in which a protective coating made of silicone rubber according to the present invention is formed on the conductor pattern 3 of FIG. 1, and FIG. 3 is a sectional view taken along line AA 'of FIG. .. As can be seen from FIG. 2 and FIG. 3, the protective coating 6 made of silicone rubber according to the present invention covers the entire conductor surface so that only the end portions 7 of each conductor in the conductor pattern 3 formed on the insulating film substrate are exposed. Is formed so as to cover the.

As described above, according to the present invention, the silicone rubber protective coating 6 is not applied to the end portions 7 of the conductors in the conductor pattern 3 formed on the tape carrier substrate. This is because the portion is subjected to surface treatment such as plating to connect with the IC terminal.

In the present invention, when forming a protective coating of silicone rubber, first, an organosilicon compound comprising a polyorganosiloxane containing a siloxane bond in the molecule as a repeating unit is formed at a predetermined portion of the conductor pattern forming surface of the tape carrier substrate. A liquid silicone material called liquid silicone rubber or RTV silicone rubber, which is a type of polymer, is applied and cured at room temperature or in a heating atmosphere depending on the curing characteristics of the liquid silicone used.

As described above, in the present invention, the reason why the protective coating is formed of silicone rubber is that the silicone rubber is excellent in heat resistance, chemical resistance, electrical insulation, weather resistance, durability and the like, and also has elasticity. In addition to having excellent properties in terms of bending resistance, silicone rubber can suppress the volatile components contained in it to around a few percent, so the vapor content of volatile components during curing after application can be reduced. This is because the shrinkage due to the dispersion is extremely small, and there is no fear of warping of the material due to curing.

In the present invention, the means for coating the silicone rubber on the conductor pattern surface on the tape carrier is, for example, a reel-to-reel type screen continuous printing machine, to which a precision screen plate such as a stainless screen is used. A method is employed in which the liquid silicone rubber is printed on a substrate including the conductor pattern at a predetermined portion on the substrate having an appropriate thickness in the range of 20 to 60 μm, and then cured by being kept at room temperature or heated. Thus,
The silicone rubber protective coating can be formed on a predetermined portion of the substrate with an accuracy of ± 0.1 to 0.3.

As the silicone rubber coated on the conductor surface, the curing temperature is 100 to 150 ° C., the rubber liquid does not adhere to the screen due to an increase in the viscosity during printing, and the volatile component even when cured by heating. It is recommended from the standpoint of workability and printing accuracy that a heat-addition-reaction-curable silicone rubber that does not cause warpage due to shrinkage of the substrate due to its low heat resistance is used.

Except for the above matters, the method of forming a conductor pattern, the method of forming a predetermined hole pattern such as a device hole, etc. are the same as those conventionally used in the manufacture of this type of tape carrier, and therefore, Detailed description is omitted.

In the tape carrier according to the present invention, as described above, the conductor pattern is completely covered with a silicone rubber which is excellent in heat resistance and chemical resistance and is highly stretchable, except for a portion which needs to be exposed. Therefore, the conductor part can be completely protected without being affected by the heat change and the use of chemicals when the tape carrier is created. Since there is no crack, there is no risk of short-circuiting or disconnection of the conductor, and since there is no deviation of the conductor connection position due to warpage, the number of pins is reduced, and the pitch is reduced. Even when high-density components are mounted, highly reliable connection can be performed without causing a cumulative pitch error of the conductor pattern.

[0018]

EXAMPLES Next, examples of the present invention will be described. Example 1 Copper / Polyimide 2 prepared by directly metalizing a copper layer on one surface of an insulating substrate made of a polyimide resin film.
Using a layered substrate, a plurality of conductor patterns of predetermined copper are formed on the copper layer surface of the substrate by a conventional method, and predetermined device holes, OLB holes and sprocket holes are formed in the polyimide resin film, and then the substrate is formed. A two-component addition reaction-curable silicone rubber is printed on a predetermined portion of the conductor pattern forming surface excluding the conductor tip portion by a screen continuous printing machine using a precision screen plate made of stainless steel. After preliminarily drying by passing through a drying oven, the substrate is wound in 100 m units on rolls with an embossed spacer tape sandwiched between them and held in a heating oven at 120 ° C for 1 hour to cure the silicone rubber. To form a silicone rubber protective coating with a thickness of 20 μm, and then, if necessary, on the exposed conductor tip where the protective coating is not applied. Performs surface treatment to create a protective coating with a tape carrier with a silicone rubber. In this example, since the heat-reaction type addition reaction curing type silicone rubber was used for the protective coating, the viscosity of the rubber liquid did not change during the printing operation during printing, so that the rubber liquid did not adhere to the screen at all. It was not seen, and the protective coating could be stably formed with high printing accuracy.

When the thus obtained tape carrier with a silicone rubber protective coating was placed on a flat base with the protective coating forming surface facing downward, the substrate was flat and no warpage was observed. Next, a 90-degree bending test was repeated 10 times on the wiring pattern surface side around the portion to be bent at the time of using the tape carrier, and then a microscope with a surface condition of the protective coating on the conductor pattern surface of 50 times was used. As a result, no crack was found in the protective coating. Example 2 A conductor pattern, a device hole, an OLB hole, and a sprocket hole were formed on a copper / polyimide two-layer substrate similar to that of Example 1 in the same manner as in Example 1, and a screen was formed on a predetermined portion of the conductor pattern forming surface of the tape carrier substrate. A one-component addition reaction curing type silicone rubber was printed by a continuous printing machine using a precision screen plate made of Stenren, and immediately after printing, it was passed through a drying oven at 50 to 100 ° C. for preliminary drying, and then, The substrate was wound on a roll in 100 m units with an embossed spacer tape sandwiched between them and held in a heating oven at 120 ° C. for 1 hour to cure the silicone rubber to form a silicone rubber protective coating having a thickness of 30 μm. If necessary, surface treatment is applied to the exposed conductor tip that is not covered with a protective coating, and is protected by silicone rubber. It has created a coated tape carrier. In this example, since the heat-reaction type addition reaction curing type silicone rubber was used for the protective coating, the viscosity of the rubber liquid did not change during the printing operation during printing, so that the rubber liquid did not adhere to the screen at all. It was not seen, and the protective coating could be stably formed with high printing accuracy.

When the thus obtained tape carrier with a silicone rubber protective coating was placed on a flat base with the surface on which the protective coating was formed facing downward, the substrate was flat and no warpage was observed. Next, a 90-degree bending test was repeated 10 times on the wiring pattern surface side around the portion to be bent at the time of using the tape carrier, and then a microscope with a surface condition of the protective coating on the conductor pattern surface of 50 times was used. As a result, no crack was found in the protective coating. Example 3 A copper / polyimide two-layer substrate similar to that of Example 1 was provided with conductor patterns, device holes, OLB holes and sprocket holes in the same manner as in Example 1, and a screen was formed on a predetermined portion of the conductor pattern forming surface of the tape carrier substrate. A continuous printing machine is used to print two-component addition reaction curing type RTV silicone rubber using a precision screen plate made of stainless steel, and after printing 100 in reel-to-reel format.
It is passed through a heating and drying oven at ˜150 ° C. for 30 minutes to be dried and heat-cured to form a silicone rubber protective coating having a thickness of 25 μm, and then the exposed conductor tip is not coated with the protective coating. Surface treatment was performed as necessary to prepare a tape carrier with a protective coating of silicone rubber. In this embodiment, since the heat-reaction type addition reaction curing type RTV silicone rubber is used for the protective coating, the viscosity of the rubber liquid does not change during the printing operation during printing, so that the rubber liquid does not adhere to the screen at all. Not seen,
The protective coating could be stably formed with high printing accuracy.

When the thus-obtained tape carrier with a silicone rubber protective coating was placed on a flat table with the protective coating forming surface facing downward, the substrate was flat and no warpage was observed. Next, a 90-degree bending test was repeated 10 times on the wiring pattern surface side around the portion to be bent at the time of using the tape carrier, and then a microscope with a surface condition of the protective coating on the conductor pattern surface of 50 times was used. As a result, no crack was found in the protective coating.

[0022]

[Comparative Example] A copper / polyimide two-layer substrate similar to that of Example 1 was used, and conductive patterns, device holes,
An epoxy thermosetting overcoat agent (containing 35% of volatile components) was used on a predetermined portion of the conductor pattern forming surface of the tape carrier substrate having the OLB hole and the sprocket hole by using a precision stainless steel screen plate. Print and immediately after printing 50
After pre-drying by passing through a drying oven at -100 ° C, the substrate is wound in 100 m units on rolls with an embossed spacer tape sandwiched between them and held in a heating oven at 130 ° C for 1 hour. A tape carrier with a protective coating made of epoxy resin, which is obtained by curing an epoxy overcoating agent to form a protective coating having a thickness of 20 μm, and then subjecting the exposed exposed conductor tip to a surface treatment if necessary. It was created.

When the tape carrier with the epoxy resin protective coating thus obtained was placed on a flat table with the surface on which the protective coating was formed facing downward, the board was placed in the widthwise direction at the inner center of the board from the flat table. It was lifted by 1 mm or more in the upward direction, and a warp was clearly observed. Next, a 90-degree bending test was repeated 10 times on the wiring pattern surface side around the portion to be bent at the time of using the tape carrier, and then a microscope with a surface condition of the protective coating on the conductor pattern surface of 50 times was used. As a result, a plurality of cracks were found in the protective coating.

[0024]

As described above, in the tape carrier with a protective coating of the present invention, the protective coating is made of silicone rubber which is highly flexible and has excellent heat resistance and chemical resistance. When used as a tape carrier for connectors, etc., the protective coating in the bent part does not crack, and when it is hardened, the tape carrier substrate does not warp, so dimensional accuracy in the terminal connection process The effect is great such that the terminals can be well connected.

[Brief description of drawings]

FIG. 1 is a plan view showing one embodiment of a tape carrier according to the present invention, showing a state of a wiring pattern surface before forming a protective coating.

FIG. 2 is a plan view showing a state of a wiring pattern surface after forming a protective coating on the tape carrier of FIG.

FIG. 3 is a cross-sectional view showing the structure of the AA ′ cross section of FIG.

[Explanation of symbols]

 1 Insulating substrate (polyimide resin film) 2 Sprocket hole 3 Conductor pattern 4 Device hole 5 OLB hole 6 Protective coating 7 Conductor end

Claims (3)

[Claims] 1. A tape carrier with a protective coating formed by coating a plurality of conductor patterns formed on an insulating film substrate with silicone rubber. 2. A plurality of conductor patterns are formed on an insulating film substrate, and then liquid silicone rubber is applied so as to cover a predetermined portion of the conductor pattern excluding conductor ends, and the liquid silicone rubber is applied. A method for producing a tape carrier with a protective coating, which comprises curing. 3. The production of a tape carrier with a protective coating according to claim 2, wherein the liquid silicone rubber is an addition reaction curable type silicone rubber, which is heated and held at 100 to 150 ° C. for curing after application. Method.