JPH03119738A - Manufacture of two-layer tab - Google Patents

Abstract

PURPOSE:To eliminate a deformation of a substrate and a lead by a method wherein, after the lead is formed on the surface of the substrate, a lead formation face is covered wholly with a metal film whose property is different from that of a metal material used as the lead, a metal layer is formed additionally on the whole surface, a polyimide layer on the rear surface of the substrate is dissolved and processed and, after that, the metal layer on the surface of the substrate is removed. CONSTITUTION:A substratum metal layer 1 is applied to the surface of a polyimide- resin film substrate 2; the layer is coated with a photosensitive resist layer 3; also the rear surface of the substrate 2 is coated with a photosensitive resist layer 4. Then, the layers 3 and 4 are irradiated with light via a photomask; the layer 3 is first developed; a resist pattern 5 is formed on the layer 1; a lead pattern 6 is formed in an exposed part of the layer 1; also the layer 4 on the rear surface of the substrate 2 is developed in the same manner; a resist pattern 7 is formed. After that, the pattern 5 is removed; the substratum metal layer 1 of the pattern 6 is dissolved; a lead 8 is formed; after that, the surface of the lead 8 is covered with a metal film 9. Then, the lead 8 and a polyimide-exposed part on the surface are covered wholly with a metal layer 10.

Description

[Detailed description of the invention] (Industrial application field) The present invention is a two-layer TAB (Tw.

Layers Dipe Automated Bon
ding).

(Prior art) In recent years, the electronics industry has been rapidly developing multifunctional devices with low cost and high reliability. There is an increasing demand for small devices that have multiple functions, are lightweight, and thin. Accordingly, the development of new element packaging technology is becoming more and more important day by day, and in particular, miniaturization and diversification of IC packages are being developed as important issues. With the progress of such element mounting technology, there is a demand for finer pin spacing that can meet the demand for increased pin counts in small IC packages.

TAB is a tape-shaped synthetic resin film substrate made of polyimide or the like, with many fine metal lead patterns for bonding, and its feature is that it has a test pad, so it can be used to detect bonding defects and chip defects after bonding. It has many advantages, such as being able to be discovered before board mounting, requiring smaller IC pads than wire bonding, and allowing for multiple pins on the negative layer.

TABs are roughly divided into three types based on their structure: IITAB, two-layer TAB, and three-layer AR. Single-layer AB is composed only of patterned metal tape such as copper foil, but since the thickness of the metal layer itself is several tens of micrometers at most, it lacks mechanical strength, and the pins that can be applied to it are poor. Since the number is limited, it is not suitable for high density. In order to compensate for the shortcomings of this one-layer TAB, a three-layer TAB was developed in which a metal foil was laminated onto a glass film substrate using an adhesive, and then the metal foil was patterned. However, due to the influence of the adhesive used as an intermediate layer, even if a highly insulating plastic film such as polyimide resin is used for the substrate, sufficient insulation between the pins cannot be ensured. have

Double-layer AR is a product in which a metal layer is formed directly on the surface of a plastic film substrate by sputtering, vacuum evaporation, plating, etc. without using an adhesive, and then patterned. Because it does not use any electrical insulation, it can be used stably without causing any problems with electrical insulation, so it is expected to have good prospects in the future.

As described above, the method for forming leads by patterning the two-layer TA8 surface involves using a dry surface treatment method such as sputtering or vacuum evaporation, or a wet surface treatment method such as electroless plating. A photosensitive resist is coated on the underlying metal layer that is adhered to the surface of the film substrate to a thickness that is greater than the thickness of the leads to be formed, masking is applied on top of this, and exposure and development processing is performed. There is an additive method in which a resist pattern is formed by electroplating, and then leads are formed by electroplating.A metal layer is formed on the underlying metal layer by electroplating in advance to the thickness of the leads, and then a resist pattern is formed by the same method as above. There is a subtractive method in which leads are formed by etching the lead.

In either case, a polyimide resin with high electrical insulation and excellent thermal stability is used for the plastic film substrate used as the base, and inexpensive and electrically conductive steel is usually used for the deposited metal layer. Ru.

In order to continuously bond the two-layer TAB obtained in this way to an IC chip, the tape feed hole (hereinafter referred to as "sprocket hole") and the lead tip are exposed and bonded to the IC chip. Hole for (hereinafter referred to as “
It is necessary to provide a hole (hereinafter referred to as "r01B hole") for connecting the rear end of the lead to an external circuit by chemical etching.

These holes are generally formed by forming a resist pattern on the polyimide side of the tape and then melting the resulting exposed portion of the polyimide resin. Immediately after forming the leads, it is necessary to apply an organic resin layer that can withstand the polyimide etching solution to protect the polyimide on the lead side. Normally, this organic resin layer is formed by applying a liquid resin and then curing it.Since a strong alkaline solution is usually used as an etching solution for polyimide, the organic resin solution is not suitable for rubber. and epoxy resins are commonly used.

(Problem to be Solved by the Invention) When applying an organic resin liquid to the lead side to form a protective layer, it is necessary to apply a heat drying process to the applied organic resin to give it strength. However, in many cases, this drying process requires heating at a temperature of 100° C. or higher.

Although the purpose of removing the solvent is achieved as a result of drying at such high temperatures, the resin layer itself shrinks during this process.
As a result, this not only causes deformation of the polyimide substrate and makes subsequent processing operations difficult, but also sometimes leads to deformation of the leads, causing a significant reduction in product yield.

It is an object of the present invention to solve the above-mentioned problems in lead protection and to provide a method for obtaining an excellent protective layer in place of the conventional organic resin layer.

(Means for Solving the Problems) To achieve the above-mentioned objects, the present invention obtains a two-layer TAB using a polyimide film with a base metal layer formed on one or both sides of the film as a base without using an adhesive. After forming leads on the upper surface of the base, the entire lead forming surface of the base is covered with a metal film made of a second metal material having different properties from the metal material used as the lead,
After that, a metal layer is further formed over the entire surface of the substrate, and then the polyimide layer on the bottom surface of the substrate is melted, and then the metal layer on the top surface of the substrate is dissolved and removed.
This is a method for manufacturing AB.

(Function) Next, details and effects of the method for manufacturing the double layer A8 according to the present invention will be explained.

FIGS. 1(a) and (b) are explanatory diagrams showing the outline of the manufacturing method of the two-layer TAB of the present invention in the order of steps, and FIG. FIG. 2 is a partial plan view showing the appearance of an example.

Figure 1 (a) shows the X-Y cross section in Figure 2, and (b)
) is a cross-sectional view of a portion corresponding to the X'-Y' cross section.

The left and right drawings in FIGS. 1(a) and 1(b) show the state of each cross section in the same process. In this description, a polyimide film substrate with a base metal layer formed on one side is used as the base, and a semi-additive method is used as the lead forming method.

In the figure, 1 is an upper base metal layer, 2 is a polyimide resin substrate, and 3 and 4 are photosensitive resist layers formed on the lower surface of the upper base metal layer 1 and the polyimide substrate 2, respectively. 5 is a resist i pattern formed by masking the resists 1 to 3 on the upper surface mainly for forming leads, and then exposing and developing them. A lead pattern 6 is formed by electroplating the exposed portion of the base metal layer 1 of the resist pattern 5. 7 is a resist pattern obtained by masking the resist layer on the lower surface so as to obtain a pattern for forming a predetermined pole, and then exposing and developing the resist layer.

Reference numeral 8 denotes a lead formed in an electrically independent state by removing the resist pattern 5 and then dissolving and removing the underlying metal layer 1 in the gap between the lead patterns 6.

A metal film 9 is formed by electrolyzing the entire surface of the lead 8. 10 is a metal layer formed over the top surface of the substrate.

11, 12, and 13 are resist patterns 7, respectively.
A device hole, a leaf B hole, and a sprocket hole are formed by dissolving and removing the exposed polyimide layer according to the method.

Next, the method for manufacturing the two-layer TAB of the present invention will be explained in order of steps.

First, a metal layer 1 is formed on one side (upper surface) of a polyimide resin film substrate 1. In the present invention, basically,
A tape-shaped polyimide resin film on which a base metal layer 1 is adhered without an adhesive is used as a base.

The adhesive-free base metal layer 1 formed on the upper surface of the polyimide resin substrate 2 is formed by applying sputtering, vacuum evaporation, electroless plating, or a combination of these methods to the surface of the substrate. Alternatively, the metal layer thus obtained may be further subjected to electrolytic plating. In short, any method may be used as long as the metal layer can be directly and reliably deposited on the polyimide resin 2 without applying an adhesive.

Copper is generally used as the metal material for the base metal layer 1 in terms of electrical performance and cost. It is also possible to try to improve adhesion strength and other properties.

The thickness of the base metal layer 1 may be such that it can withstand the soft etching that is performed as a pretreatment during metal electroplating that is performed when forming a lead pattern, and there is no particular restriction on the thickness, but the thickness may be such that it can withstand the soft etching that is performed as a pretreatment during metal electroplating that is performed when forming a lead pattern. In view of the workability of the partial melting process of the base metal layer 1 for formation, it is desirable that the thickness be in the range of 0.05 to 2 μm.

Next, a photosensitive resist layer 3 is applied onto the base metal layer 1.

Since the resist used for this is required to have a lead thickness of 35 μm, any resist that can be coated thicker than that is sufficient.

As for the type of resist, any commercially available resist is sufficient as long as it can be applied thickly as described above and can withstand the electroplating solution used in forming the lead pattern.
A negative resist in which a photosensitive functional group is added to an acrylic resin or the like so that the light-irradiated portion remains as an undissolved portion during development;
There are positive resists in which a photosensitive functional group is added to a novolac resin etc. so that the light irradiated area dissolves during development, but either type can be used by reversing the photomask pattern. .

Further, it can be used in either a liquid state or a solidified dry film form.

When using a liquid resist, in addition to general coating methods such as the bar code method, dipco-1 method, and spin code method, electrostatic coating methods that charge the resist liquid and apply it in the form of a spray can also be used. good. It also needs to be able to withstand the electroplating solution used for lead formation.

Next, a photosensitive resist is applied to the lower surface of the polyimide to form a resist layer 4 (step (a)). The resist layer 4 formed on the polyimide surface may be of any material as long as it can withstand the solution used to dissolve and remove the polyimide. Generally, a polyimide solution is strongly alkaline, so a rubber resist is suitable. The thickness of the resist layer 4 is also not particularly limited, but if the pattern accuracy of the polyimide after melting is taken into account, it is preferably about 2 to 10 μm.

Generally, in order to form a pattern using a resist, it is necessary to purge the solvent contained in the resist after applying the resist. This has the effect of imparting strength to the resist itself and improving the adhesion between the substrate and the resist. The solvent is usually removed by heating and drying, and the processing temperature at this time is within a range that does not reduce the resolution of the resist. Further, in order to further strengthen the pattern formed by exposure and development, a method is adopted in which heat treatment is performed at a temperature higher than the drying temperature used to remove the solvent described above.

Next, the resist layer 3 and the resist itself 4 are each irradiated with appropriate amounts of light through a photomask, and the resist layer 3 is first developed to form a resist pattern 5 on the base metal layer 1. The light used to expose the resist is determined by the characteristics of the resist, but ultraviolet light is usually used. Furthermore, the photomask referred to herein is one in which an emulsion containing silver or the like or a metal such as chromium is baked onto a glass or transparent plastic film.

Exposure methods include a contact exposure method in which the resist surface and the photomask are brought into close contact, and a projection exposure method in which the resist surface and the photomask are parallel to each other at a certain distance, but either method may be used in the present invention. .

Next, a lead pattern 6 is formed by electroplating a plated metal on the exposed portion of the base metal layer 1 that is formed according to the resist pattern 5 formed on the upper surface of the substrate, and a resist pattern 7 is formed by developing the resist layer 4 on the lower surface of the substrate. Form (process (b)).

Next, the resist pattern 5 is removed and the underlying metal layer of the lead pattern 6 is dissolved to form the lead 8 (step (c)).
). After forming the leads 8 on the top surface of the base in this way,
The surface of the lead 8 is coated with a metal film 9. The metal film 9 used to cover the lead 8 is formed of a metal that can be deposited by electroplating since the lead itself has electrical conductivity. - For example, if the lead 8 is made of copper, the metal material for forming the metal film may be gold, silver, nickel, tin, lead, zinc, etc.

Next, the metal layer 10 is completely covered with the metal layer 10 (step (d)).
). The metal layer 10 is formed evenly on the polyimide which is not exposed between the metal film 9 formed on the lead 8 and the lead 8 on the upper surface. Therefore, the formation method is not based on an electrical method, but a sputtering method, a vacuum evaporation method, an electroless plating method, etc. are suitable. The metal material for forming the metal layer 10 may be any material as long as metal layers can be stacked by such a formation method, and examples thereof include copper, gold, silver, nickel, and chromium. Further, the metal layer 10 may be formed by the above-described forming methods alone or in combination.

It is also conceivable to form the metal layer in the form of a thin film in this manner, and then to increase the thickness by forming the same or different metals on the thin film by electroplating. In short, a metal layer 10 with a certain degree of strength is formed on the upper surface of the base.
All you have to do is form.

Regarding the combination of metal materials for forming the lead 8, metal film 9, and metal layer 10, it is necessary to use different types of metal materials for forming the lead 8 and metal M9. There are no particular restrictions other than this. That is, the metal material forming the lead 8 and the metal material forming the metal layer may be of the same type or different types, and similarly, the metal material forming the metal film 9 and the metal material forming the metal layer 10 may be of the same type or different types. But that's fine.

Next, the exposed polyimide on the lower surface is melted to form the device hole 11, the leaf hole 12, and the sprocket hole 13 (e). Polyimide is generally dissolved using a strong alkaline solution such as hydrazine hydrate or an alkali hydroxide solution, alone or in combination, or with a solution containing a mixture of methyl alcohol, ethyl alcohol, globil alcohol, etc.

Next, after removing the resist pattern 6, the metal layer 10 is removed (step (step)). At this time, the metal film 9 may be melted at the same time as the metal layer 10, and then the leads 8 may be coated with another metal again depending on the application.

The metal film 9 and the metal layer 10 are generally dissolved using an acidic solution such as hydrochloric acid, sulfuric acid, or nitric acid, a metal chloride solution such as an iron chloride solution or a copper chloride solution, or a peroxide solution such as an ammonium persulfate solution. It is.

Above, we have described the case where a base metal layer is formed on the top surface of a polyimide resin substrate without applying an adhesive, and leads are formed by a semi-additive method. Even if the subtractive method is used, in which a metal layer with the same thickness as the lead is formed without adhesive, a resist pattern is formed on top of it, and the exposed metal layer is etched to form the lead, the steps after forming the lead are It goes without saying that a method similar to the case of employing the semi-additive method described above can be employed. Further, since either an additive method or a subtractive method can be applied as a lead forming method, it can be said that the method of the present invention is extremely suitable for manufacturing a two-layer TAB.

Although the above explanation relates to a method for forming a polyimide film on one side, it can easily be applied to forming a polyimide film on both sides.

(Example) Next, examples of the present invention will be described.

Example 1 Copper sulfate 10g/'ρ, ED
TA60g/', 11, formalin 6m12/', f
), dipyridyl 30 g/'ρ, polyethylene glycol 0.5 g/', using an electroless copper plating solution having the composition of After forming the plating coating, further add 100 g/'fJ of copper sulfate and 180 g/'J of sulfuric acid.
Using an electrolytic copper plating solution having a composition of , a current density of 2
Electrolysis was performed at A/'dm2 to form a metal layer of copper with a thickness of 1 μm on the upper surface.

Next, put PHER・HC600 (manufactured by Tokyo Ohka Co., Ltd.,
Negative photoresist) was coated to a thickness of approximately 40 μm, and FR3 (manufactured by Fuji Pharmaceutical Co., Ltd., negative photoresist) was coated to a thickness of approximately 7 μm on the lower surface of the polyimide substrate using a bar coater, and each was heated at 70°C. After drying for 30 minutes, an A8 pattern with a size of 48mm x 48+nm, an inner lead pitch of 160 μm, an inner lead width of 70 μm, and 244 leads was formed on the upper resist layer. A glass photomask made of glass was placed in close contact with the resist surface and 900 mJ of ultraviolet rays were irradiated.
A photomask made of glass of the same size as the top surface and having one device hole, four leaf B holes, and 16 sprocket holes, which correspond to the TAB pattern on the top surface, is tightly attached to the bottom resist layer. Exposure was performed by irradiating 100 mJ of ultraviolet light. Please do not use an ultra-high pressure mercury lamp (manufactured by Oak Seisakusho Co., Ltd.) for ultraviolet irradiation.

Next, apply the upper resist layer to P)lEI'? After developing at 25° C. for 7 minutes using a developer (manufactured by Tokyo Ohka Co., Ltd.) to obtain a predetermined pattern, heat treatment was performed at 110° C. for 30 minutes. Subsequently, electrolytic copper plating was applied to the exposed copper portions at a current density of 2 A/'dm2 for 50 minutes to obtain a lead pattern with a thickness of approximately 35 μm. Remove residual resist on steel with sodium hydroxide
% solution at 50° C. for 1 minute, and then the underlying metal layer between the leads on the upper surface was etched with an ammonia-based alkaline solution to make the leads electrically independent. After that, apply gold plating liquid (
(manufactured by NE Chemcat) and N-44) at a current density of IA/'dm2 for 3 minutes to coat the lead surface with approximately 2.
μm of gold was deposited. Next, a copper coating was formed on the entire upper surface of the substrate using the electroless copper plating solution described above, and the thickness was further increased by electrolytic copper plating so that the thickness of the copper layer was about 10 μm. No distortion or deformation of the substrate was observed as a result of these treatments.

Next, apply the bottom resist layer to FI? After developing for 50 seconds at 25°C using S-D (manufactured by Fuji Yakuhin Co., Ltd.), developing at 130°C for 3
A post-heat treatment was performed for 0 minutes. Next, using a mixture of ethyl alcohol and 1N potassium hydroxide solution in a volume ratio of 1:1, the polyimide was dissolved without being exposed at 50°C for 4 minutes, and the device hole, leaf B hole, and sprocket 1 were dissolved. After each through-hole is formed, the remaining resist is removed using FR3#I synergist (manufactured by Fuji Yakuhin Co., Ltd.).
It was removed by treatment at °C for 15 minutes.

Next, the copper layer on the top surface was dissolved using a 5% ammonium persulfate solution at 50° C. for 7 minutes to expose the leads covered with the gold plating previously formed. There are no signs of deformation in any part of the exposed leads, and the condition is no different from the state of the leads before electroless plating was applied.

Example 2 A polyimide resin film similar to that in Example 1 was used as a starting material as a base, and 0 was applied to the upper surface by sputtering.
．． Using a substrate on which a base copper layer with a thickness of 25 μm was formed and the thickness was further adjusted to 1 μm by electrolytic copper plating, each treatment was performed in the same manner as in Example 1. As a result, the same performance as in Example 1 was obtained. It was possible to obtain a two-layer TAB having the following properties.

Example 3 Using the same polyimide resin film as in Example 1 as a starting material, a copper base layer with a thickness of 1 μm was formed on its upper surface, and the copper layer was further electrolytically plated on top of it to a thickness of 35 μm. Copper was deposited in such a manner that On the copper layer on the upper surface of the substrate, ERH/HC40 (manufactured by Tokyo Ohka Co., Ltd., negative photoresist) was applied to a thickness of about 5 μm, and on the bottom surface of the substrate was applied FSR (manufactured by Fuji Yakuhin Co., Ltd., negative photoresist) about 7 μm thick.
Coat each using a bar coater to a thickness of μm,
After each was dried at 70°C for 30 minutes, a photomask with a TAB pattern similar to that in Example 1 was applied, and the upper resist layer was irradiated with 200 mJ of ultraviolet rays, and the lower resist I layer was irradiated with 100 mJ of ultraviolet rays. did. Next, the resist on the upper surface was developed at 25° C. for 2 minutes using P) IER developer (manufactured by Tokyo Ohka Co., Ltd.) to form a prescribed resist pattern, which was then heat-treated at 110° C. for 30 minutes. Next, the exposed copper portion on the top surface was treated with a 200 g/'1 solution of copper chloride at 50° C. for 10 minutes to dissolve it and form leads. Residual resist on the steel was removed by treatment with t1% sodium hydroxide solution at 50° C. for 1 minute.

Subsequent gold plating of the leads, formation of a copper coating on the upper surface of the substrate, formation of a resist pattern on the lower surface of the substrate, dissolution of polyimide, peeling off of the residual resist on the lower surface of the substrate, and dissolution of the copper layer on the upper surface of the substrate were performed in the same manner as in Example 1. However, a two-layer TAB similar to that obtained in Example 1 could not be obtained.

Example 4 The same polyimide resin as in Example 1 was used as the starting material, and the steps up to lead formation were carried out in the same manner as in Example 1. After that, metallic nickel was applied to the lead surface to a thickness of about 2 μm by electro-nickel plating. It was deposited to a thickness. Next, a copper layer is formed on the entire top surface of the substrate by electroless copper plating, and a metal layer is further formed on top of it by electrolytic copper plating.The steps from forming a resist pattern on the bottom surface of the substrate to dissolving the polyimide are performed in the same manner as in Example 1. After processing, the metal layer formed on the top surface of the substrate was dissolved and removed to produce a two-layer TAB.
A product equivalent to Example 1 was obtained.

Example 5 The same polyimide resin as in Example 1 was used as the starting material for the base, and after the lead surface was covered with gold plating in the same manner as in Example 1, electroless nickel was applied to the entire upper surface of the base. A nickel plating layer is formed by plating using a conventional method, and then electrolytic nickel plating is applied on top of the nickel plating layer.
A nickel layer with a thickness of μm is formed, and the steps from forming a resist pattern on the bottom surface of the substrate to dissolving the polyimide are carried out in the same manner as in Example 1. After that, the nickel metal layer formed on the surface of the substrate is dissolved and removed to form a two-layer TAB. When manufactured, a product equivalent to Example 1 was obtained.

Comparative Example 1 Polyimide resin film-like substrate with a size of 5ay+X15 (7) (manufactured by Toshi DuPont, Kapton 200)
1. Using 4 pieces with a thickness of 50 μm>10 g/' of copper sulfate, l! , 60g EDTA
/'ρ, Horn J 6 mQi'D, Dihyridyl 3
Using an electroless copper plating solution having a composition of 0mz/', ll, ;t") and 0.5 g/'ρ of copper, the copper After forming the electroless plating coating, a current density of 2 A/'dm was applied using an electrolytic copper plating solution having a composition of 100 g/'ρ of copper sulfate and 180 g/'ρ of sulfuric acid.
2, perform electrolysis to form a 1 μm thick copper metal layer on the top surface. Next, PHER on the top surface.

HC600 (manufactured by Tokyo Ohka Co., Ltd., negative photoresist) was applied to a thickness of approximately 7 μm using a bar coater, and after drying at 70°C for 30 minutes, the upper resist layer was coated with a 48 mm x 48 mm film. Now, the inner lead pitch is 160μm, and the inner lead width is 70μm.
A glass photomask formed by arranging a TAB pattern with 244 leads in a square shape was brought into close contact with the resist surface and irradiated with 900 mJ of ultraviolet rays. Made of glass, with TA on the top
A photomask in which one device hole corresponding to pattern B, four leaf B holes, and 16 sprocket holes were formed was brought into close contact with the photomask and 100 mJ of ultraviolet rays were irradiated to perform exposure. Do not use an ultra-high pressure mercury lamp (manufactured by Oak Seisakusho Co., Ltd.) for ultraviolet irradiation.

Next, the upper resist layer was developed using P) IER developer (manufactured by Tokyo Ohka Co., Ltd.) at 25°C for 7 minutes to obtain a predetermined pattern, followed by post-heat treatment at 110°C for 30 minutes. I did it. Subsequently, a current density of 2 A/'dm2 was applied to the exposed part of the copper.
After 0 minutes of electrolytic copper plating and burying to a thickness of about 35 μm, the base metal layer between the leads on the top surface is etched with an ammonia-based alkaline solution to make the leads electrically independent. I made it. After that, the above-mentioned FR3 was applied to the entire top surface to a thickness of about 20 μm and dried at 130°C for 30 minutes. The film deformed into a concave state on the top surface, and one of the four AR pieces was The inner lead is deformed due to the deformation of PSH, and the other is FSI? A crack appeared in a part of the surface, exposing the polyimide on the top surface, and during the next step of melting the polyimide, the exposed polyimide portion on the surface side melted, making it impossible to commercialize any of them. In other words, two of the four pieces initially introduced were not completed products, and the yield was 50%.

(Effects of the Invention) As described above, according to the method for manufacturing a two-layer TAB according to the present invention, it is possible to eliminate the reduction in product yield due to deformation of leads in the conventional method for manufacturing a two-layer TAB. is enormous.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of the method for manufacturing a two-layer TAB according to the present invention in step j1@, and FIG. 2 is an external plan view of the two-layer TAB obtained according to the present invention. DESCRIPTION OF SYMBOLS 1... Base metal layer, 2... Polyimide base, 3...
- Cyst layer, 4... Resist layer, 8... Lead, 9... Metal film, 10... Metal layer.

Claims (1)

[Claims] (1) When obtaining a two-layer TAB using a base metal layer formed on one or both sides of a polyimide film without using an adhesive, after forming leads on the upper surface of the base, the entire lead-forming surface of the base is is coated with a metal film made of a second metal material with different properties from the metal material for lead formation, and then a metal layer is further formed over the entire surface of the base, and then the polyimide layer on the bottom surface of the base is melted. A method for producing a two-layer TAB, characterized in that the metal layer on the upper surface of the substrate is then dissolved and removed.