JPH06140473A - Manufacture of bumped tape - Google Patents

Abstract

PURPOSE:To make a TAB tape inspectable after mounting even when the tape is not directly bonded to external circuits and, at the same time, to surely form bumps having excellent dimension stability on the tape even when the number of pins increases or the pitch of the bumps becomes narrower by applying a two-layer TAB manufacturing method. CONSTITUTION:After forming photosensitive resist layers 3 and 4 on the upper and lower surfaces of a substrate composed of a polyimide resin film 2 and metallic layer 1 formed on the upper surface of the film 2 and a resist pattern 5 on the upper surface of the substrate, lands and a circuit pattern 6 are formed by electroplating a metallic layer 6 to the surface of the exposed layer 1. After forming a resist pattern 7 on the lower surface of the substrate and organic resin film 8 on the entire upper surface of the substrate, holes 9 and 10 are formed by removing the exposed polyimide resin by dissolution. Then only the hole 10 is covered with an organic resin film 11 and a bump 12 is formed in the hole by electroplating. Finally, the organic films 8 and 11 are removed and the metallic layer 1 on the upper surface of the substrate is removed by dissolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bumped tape used for joining a mounting substrate such as TAB (tape out mating do bonding) or FPC (flexible printed circuit) to an external circuit. .

[0002]

2. Description of the Related Art In recent years, there has been a rapid increase in the trend toward lightness, thinness, shortness and high functionality in the field of electronic equipment. In response to this tendency, it is required for a package to be equipped with a chip that has a large number of pins and is thin as the electronic device becomes smaller and has higher functionality. TAB is used as a mounting technique capable of coping with the increase in the number of pins of such a chip. The level of the multi-pin required for the TAB is in the 1000-pin class, which further narrows the pitch, and a TAB of 70 μm pitch has been developed for the inner lead.

The technique for connecting the TAB tape and the external circuit is generally performed by using the outer lead of the TAB tape. However, since the lead is soft and easily bent, and the types of the external circuit and the electrode are various, QFP ( It is much more difficult than the quad flat package), and this technology is a field that is behind in the field of TAB technology.

There are mainly three methods of connecting the outer lead of the TAB tape to the external circuit. 1
One is the soldering method. In this method, the outer leads of the TAB tape and the electrodes of the external circuit are plated and connected by thermocompression bonding. The second is a method using an anisotropic conductive sheet. In this method, the dispersed sheet is interposed between the outer lead of the TAB tape and the electrode of the external circuit, and the resin is softened by thermocompression bonding, thereby electrically contacting with the fine particles dispersed between the lead and the electrode. It is what makes me. In this method, the connection with the lead pitch of 100 μm is completed at the laboratory level, and there is a problem that it is not suitable for narrowing the pitch and there are metal fine particles between the electrodes.
There is a problem that the insulation resistance between the electrodes is reduced and crosstalk occurs. The other is a method using a photocurable insulating resin. This method is a method in which a photocurable insulating resin is interposed between the outer lead of the TAB tape and the electrode of the external circuit, and the resin is cured to make a connection. However, in these methods, electrical inspection is difficult without bonding the TAB tape and the external circuit. Therefore, even if a problem occurs in the external circuit after connection, it is impossible to separate the TAB tape and the external circuit. There is a problem that the TAB tape and the chips mounted on the TAB tape are wasted.

Further, various kinds of tapes with bumps, which are the object of the present invention, have been proposed, but an efficient method for producing them has not been established yet.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique for producing a two-layer TAB (see, for example, Japanese Patent Laid-Open No. H03-03242).
The technology described in Japanese Patent Publication No.-83354) is applied to
The outer lead of the AB tape is not used, but the one formed by connecting the hole on the back surface of the pad formed on the TAB tape and the bump of the bumped tape is used. When connecting the TAB tape and the bumped tape of the external circuit,
Even if the B tape and the external circuit are not directly bonded,
It is another object of the present invention to provide a novel manufacturing method of a bumped tape having a bump capable of inspecting after mounting and having excellent dimensional stability corresponding to a large number of pins and a narrow pitch.

[0007]

The method of the present invention for solving the above-mentioned problems is based on a substrate in which a metal layer is directly formed on the upper surface of a polyimide resin film as a base, After forming a photosensitive resist layer, a photomask having a predetermined land and circuit pattern is applied to the resist layer on the upper surface of the substrate, and a photomask having various hole patterns to the resist layer on the lower surface of the substrate. And irradiating the lower surface of the substrate with light, and then developing the resist on the upper surface of the substrate to form a resist pattern on the upper surface of the substrate, by electroplating on the exposed metal layer according to the resist pattern formed on the upper surface of the substrate. By laminating a metal plating layer and then dissolving and removing the resist layer on the upper surface of the substrate, land and A second step of forming a circuit pattern, then developing a resist on the lower surface of the substrate to form a resist pattern on the lower surface of the substrate, and then forming an organic resin film on the entire upper surface of the substrate, according to the resist pattern formed on the lower surface of the substrate Third step of forming predetermined various holes in a predetermined portion by dissolving and removing the exposed polyimide resin, and covering only specific holes of the various holes formed on the lower surface of the substrate with an organic resin coating, and then the substrate Fourth step of forming predetermined bumps by electroplating on holes not covered with the organic resin coating among various holes formed on the lower surface, removing the organic resin coating on the upper and lower surfaces of the substrate, and then on the upper surface of the substrate It is characterized in that it comprises a fifth step of dissolving and removing the directly formed metal layer.

[0008]

Next, the details of the method of manufacturing the bumped tape according to the present invention and its operation will be described with reference to FIGS. 2, 3, 4, and 5. Upper surface metal layer and substrate upper surface resist pattern forming step:
In the present invention, basically, a tape-shaped polyimide resin film in which the upper surface metal layer 1 is formed only on the upper surface without using an adhesive is used as the polyimide resin substrate 2. Since no adhesive agent is interposed between the polyimide resin substrate 2 and the upper surface metal layer 1, a positional deviation due to softening due to heat does not occur and dimensional accuracy is good.

The upper surface metal layer 1 is formed on the upper surface of the polyimide resin substrate 2 by a sputtering method, a vacuum deposition method or an electroless plating method, or a metal layer is formed by combining these methods, or by these methods. Further, an electrolytic plating method may be further combined, and any method can be adopted as long as it is a method of directly forming a metal layer on the polyimide resin substrate 2 without applying an adhesive.
Copper is generally used for the upper surface metal layer 1 formed on the polyimide resin substrate 2 in consideration of electrical properties and economical aspects, but a thin film layer of chromium, nickel, or the like is formed between the polyimide resin substrate 2 and copper. There is no problem even if there is.

The thickness of the upper surface metal layer 1 formed on the upper surface of the substrate is such that the land 6 is formed by a semi-additive method using electroplating after electroless plating is performed.
There is no particular limitation as long as it has a thickness that can withstand the etching in the pretreatment in the electroplating performed during the formation of the metal, but the work of the partial melting step of the upper surface metal layer 1 for separating the lands described below is further performed. Considering 0.1
It is preferably in the range of 2 μm.

Since the land 6 is formed by the semi-additive method, the land 6 has a rectangular cross section. On the other hand, when the subtractive method of forming a wiring pattern by etching is used, the cross section of the land becomes a trapezoid, so by comparison, the former has a larger cross section even with the same land width, so the mechanical strength and allowable current are Higher, suitable for narrow pitch.

Further, the thickness of the photosensitive resist layer 3 formed on the upper surface metal layer 1 may be 10 to 40 μm or more necessary for the land 6 to be formed.

Any commercially available resist may be used as long as it can be applied to the above thickness and can withstand the electroplating solution carried out when the land 6 is formed on the upper surface. By imparting a photosensitive functional group to a resin or the like, the light-irradiated portion remains as an undissolved portion.Negative resist, or by applying a photosensitive functional group to a novolak resin, the light-irradiated portion is dissolved during development. Although there is a type resist, any type of resist can be used by reversing the pattern of the photomask.

The resist may be liquid or solidified into a dry film.

When a liquid resist is used, the coating on the metal layer of the substrate is not only a general coating method such as a bar coating method, a dipping method or a spin coating method, but also a static coating method in which the resist solution is charged and sprayed. An electrocoating method may also be adopted.

Further, the photosensitive resist layer 4 formed on the lower surface of the polyimide resin substrate 2 may be any one as long as it can withstand the polyimide resin solution used for forming holes, and generally, the polyimide resin solution is Since a strong alkaline solution is used, it is desirable to use a rubber resist. Although the thickness of the photosensitive resist layer 4 formed on the lower surface of the polyimide substrate is not particularly limited, it is preferably about 2 to 10 μm in consideration of the pattern accuracy of holes after the polyimide resin is dissolved.

Generally, in order to form a pattern with a resist, it is necessary to remove the solvent contained in the resist after applying the resist. This is done to improve the strength of the resist itself and at the same time to improve the adhesion between the resist and the metal layer. The solvent is usually removed by a drying process. At this time, the processing temperature is the resolution of the resist. It is better to increase the value so that it does not decrease. In addition, heat treatment may be performed to make the pattern formed after exposure and development stronger, but in this case, a temperature higher than the temperature used in the solvent removal treatment described above is adopted.

Next, a photomask having a desired pattern is applied to the photosensitive resist layers 3 and 4 formed on the upper surface metal layer 1 and the polyimide resin substrate 2, and each is irradiated with an appropriate amount of light, and first, The resist on the upper surface of the substrate is developed to form a resist pattern 5 on the upper surface metal layer 1. A photomask mainly for land formation is formed on the photosensitive resist layer 3 on the upper surface of the substrate, and a photosensitive resist layer on the lower surface. Photomasks 4 are mainly used for forming various holes. As a photomask for forming the resist pattern on the upper surface of the substrate, for example, one as shown in FIG. 4 can be cited.

The photomask for forming the resist pattern on the lower surface of the substrate may be, for example, as shown in FIG. 5, and the resist pattern for forming holes such as tooling holes and blind holes is mainly used. Can be formed.

The wavelength of the light irradiated for exposing the resist is determined by the characteristics of the resist, but ultraviolet rays are generally used. Further, the photomask referred to here is one obtained by baking an emulsion containing silver or the like or a metal such as chrome on a glass or translucent plastic film.

As the exposure method, there are a contact exposure method in which the resist surface and the photomask are brought into close contact with each other, and a projection exposure method in which the resist surface and the photomask are arranged in parallel at a constant distance. You may adopt the method of. (See FIGS. 2 (a) (b) (c) above)

Land formation and substrate lower surface resist pattern
The step of forming the land is such that the exposed portion of the upper surface metal layer 1 generated by the resist pattern 5 is electroplated, and the land 6 is formed by laminating to a desired thickness or more, and then the resist on the lower surface of the substrate is developed. A resist pattern 7 is formed on the polyimide resin substrate 2, and the resist pattern 5 is dissolved and removed to form a land 6.

Immediately after the land is formed, the organic resin film 8 is applied over the entire upper surface of the substrate. The film formed by the organic resin film 8 has a role of protecting the polyimide resin substrate 2 exposed on the upper surface of the substrate and a role of reinforcing the substrate during a hole forming process by subsequent dissolution of the polyimide resin, and masking at the time of forming bumps described later. To play the role of. This organic resin coating may be any one that can withstand the solution of the polyimide resin and the electroplating solution used in the bump formation process described below.Because a strong alkaline solution is used as the solution of the polyimide resin, it is rubber-based or epoxy-based. A silicon-based organic resin or the like may be used.
(See FIGS. 2 (d) (e) (f) above.)

Hole Forming Step In forming various holes, the exposed polyimide resin is dissolved according to the resist pattern 7 formed on the lower surface of the substrate to open the resin in this portion and form blind holes 9 for bump plating. , The touring hole 10 is formed. In this case, for dissolving the polyimide resin, it is advisable to use a solution in which a strong alkaline solution such as hydrazine hydrate and an alkali hydroxide is used alone or mixed, and further methyl alcohol, ethyl alcohol, propyl alcohol and the like are mixed. In addition, the shape of the hole for forming bump plating formed in this step is a perfect circle, a square, an ellipse, etc.
Any shape may be used. (See Figure 2 (g) above)

Bump Forming Step After forming various holes, only the tooling holes 10 are masked with the organic resin film 11 from the lower surface of the substrate. The masking by the organic resin film 11 is performed by electroplating in the subsequent bump forming process by the tooling hole 1
This is for preventing the metal layer from being stacked on the layer 0. Therefore, the organic resin coating 11 may be a commercially available one as long as it can withstand the pretreatment liquid or the electroplating liquid in the bump forming process, and the thickness of the organic resin coating 11 can be adjusted by the pretreatment liquid or the electroplating liquid. There is no particular limitation as long as it can withstand.

To form the bumps, electroplating is performed on the back surface of the land 6 formed on the upper surface of the base in the blind hole 9 for forming bumps formed on the lower surface of the base, and a metal layer is laminated to a predetermined thickness. Done by The bump height is required to be equal to or larger than the thickness of the polyimide resin substrate 2. The height of the bump is required to be at least 50 μm or more from the polyimide resin substrate 2 when the depth of the hole on the back surface of the pad of the TAB tape to be connected is 50 μm, but considering the yield of bonding, the height of the bump is 60 μm. The above is necessary. (See Figure 2 (h) above)

Dissolving and removing various resists and underlying metal layers
After removing the various resists formed on the upper and lower surfaces of the substrate,
A bumped tape as shown in FIG. 3 is obtained. A commercially available solution may be used as a solution for removing various resists. After removing the various resists, the upper surface metal layer 1 (base metal layer) formed on the upper surface of the substrate is dissolved and removed. The dissolution and removal of the upper surface metal layer 1 (base metal layer) electrically separates the lands 6 formed on the lower surface of the substrate.

As the solution for dissolving the upper surface metal layer 1, generally, an acidic solution such as hydrochloric acid, sulfuric acid, nitric acid, a metal chloride solution such as an iron chloride solution, a copper chloride solution, an ammonium persulfate solution, or the like is used. A peroxide solution or the like is used. (End of Figure 2
(See (i))

As described above, according to the method of the present invention, by utilizing various means in each step depending on the situation, it is possible to accurately form the leads on the upper surface of the substrate, form various holes in the polyimide resin substrate, and form the substrate. The bottom bumps can be formed.

The bumped tape manufactured by the above-mentioned method can be plated with tin, nickel or gold on the surfaces of the bumps and lands depending on the purpose of use.
As a method of plating with tin, nickel and gold, an electroless plating method is adopted because the bumps and lands are not electrically connected.

FIG. 1 shows a sectional view of a case where the tape with bumps is used for mounting. That is, the external circuit 14 and the TAB
It has a structure in which a bumped tape manufactured by the method of the present invention is sandwiched between the tape 13 and the tape 13.

[0032]

[Example] (Example 1) 18 cm x 1 as a starting material
A 5 cm size, 50 μm thick polyimide resin film having an electroless copper plating film of 0.6 μm thickness was used on Esperflex (Sumitomo Metal Mining Co., Ltd.), and the electroless copper plating film was used as a base copper layer. did. Next, P on the underlying copper layer
MER HC 600 (negative photoresist, manufactured by Tokyo Ohka Co., Ltd.) was applied to a thickness of 40 μm by a spin coater, and then dried at 70 ° C. for 30 minutes. Then, apply FSR (Negative photoresist, manufactured by Fuji Yakuhin Co., Ltd.) on the opposite surface with a spin coater to a thickness of 7 μm, and then apply 3 at 70 ° C.
It was dried for 0 minutes.

The resist layer on the underlying copper layer has a diameter of 300
A glass photomask in which 171 patterns of 171 μm land patterns are arranged in series is adhered to the resist surface to irradiate with 900 mJ of ultraviolet rays, and the resist on the lower surface corresponds to the landing pattern on the upper surface. 4 patterns, blind hole pattern 171
A photomask having a plurality of pieces was brought into close contact with each other and irradiated with 100 mJ of ultraviolet rays for exposure. Ultra-high pressure mercury lamp (Oak Seisakusho) was used for irradiation with ultraviolet rays. Next, the resist layer on the upper surface was developed with a PMER developer (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 25 ° C. for 5 minutes to obtain a predetermined resist pattern, and then dried at 110 ° C. for 30 minutes.

Subsequently, an electric copper plating solution having a composition of 100 g / l of copper sulfate and 180 g / l of sulfuric acid was used on the exposed underlying copper layer on the upper surface of the substrate to obtain a current density of 2 A / dm ² of 25.
Electrolysis was performed at 50 ° C. for 50 minutes to form a land pattern having a thickness of 35 μm. Next, the resist layer on the lower surface of the substrate is changed to FSR-D.
(Manufactured by Fuji Yakuhin Co., Ltd.), the resist is developed at 25 ° C. for 50 seconds to obtain a predetermined resist pattern, and then dried at 130 ° C. for 30 minutes. At 50 ° C. for 1 minute to remove.

Next, the above-mentioned FSR was applied to the entire upper surface of the substrate to a thickness of 40 μm and dried at 130 ° C. for 30 minutes.

Subsequently, the polyimide resin exposed on the lower surface of the substrate was dissolved at 50 ° C. for 6 minutes using a liquid in which a 4N potassium hydroxide solution and ethyl alcohol were mixed at a volume ratio of 1: 1 to dissolve the tooling holes and A blind hole was formed.

Next, only the tooling holes formed on the lower surface of the substrate are masked by the above-mentioned FSR, and 130 ° C.
And dried for 30 minutes. Next, electrolysis was performed for 50 minutes at a current density of 4 A / dm ² using the above-mentioned electroplating solution on the exposed back surface of the underlying copper in the blind holes formed on the bottom surface of the substrate to form bumps having a height of 80 μm from the polyimide surface. .

Subsequently, the FSR formed on the upper and lower surfaces is
Using an SR stripper (manufactured by Fuji Yakuhin Co., Ltd.), the solution was stripped by dissolution at 70 ° C. for 10 minutes, and then the underlying copper layer on the upper surface of the substrate was copper chloride
It was possible to manufacture a bumped tape by dissolving and removing the land by using a 00 g / l solution to make the land electrically independent.

When the height of the bump was measured by an optical step measuring machine, the accuracy was ± 5 μm. Also,
After mounting this tape with bumps, blower incubator TYP
Using EDN-43 (Daiwa Scientific Co., Ltd.),
Even after a 500-hour environment resistance test, the pitch deviation was 0.
It was less than 05%.

(Example 2) As a starting material, an etcher flex (Mitsui Toatsu Kagaku) having a 0.6 μm thick underlying copper layer formed by sputtering on a polyimide resin film having the same size and thickness as in Example 1 was used. (Manufactured by Co., Ltd.)
Other processes were performed in the same manner as in Example 1 except for the above, and thus a bumped tape could be manufactured in the same manner as in Example 1. When the height of the bump was measured by an optical step measuring machine, the accuracy was ± 5 μm. Also, after mounting this tape with bumps, blower constant temperature incubator TYPEDN
-43 (Daiwa Scientific Co., Ltd.), 150 ° C, 500
Even if a time environment resistance test is performed, the pitch shift is 0.05%
It was below.

(Example 3) As a starting material, an etcher flex (Mitsui Toatsu Kagaku) having an underlying copper layer of 0.25 μm thickness formed by sputtering on a polyimide resin film having the same size and thickness as in Example 1 was used. When each treatment was performed in the same manner as in Example 1 except that the tape with bumps was manufactured, a bumped tape could be manufactured in the same manner as in Example 1. When the height of the bump was measured by an optical step measuring machine, the accuracy was ± 5 μm. Also, after mounting this tape with bumps, blower constant temperature incubator TYPE
Using DN-43 (Daiwa Scientific Co., Ltd.), 150 ° C., 5
Even if the environment resistance test is performed for 00 hours, the pitch shift is 0.0
It was 5% or less.

(Example 4) As a starting material, a polyimide resin film having the same size and thickness as in Example 1 was used.
Using Esperflex (manufactured by Sumitomo Metal Mining Co., Ltd.) having a 25 μm electroless copper plating film, further using a substrate in which the thickness of the underlying copper layer was adjusted to 1 μm by electrolytic copper plating,
Other processes were performed in the same manner as in Example 1 except for the above, and thus a bumped tape could be manufactured in the same manner as in Example 1. When the height of the bump was measured by an optical step measuring machine, the accuracy was ± 5 μm. Also, after mounting this tape with bumps, blower constant temperature incubator TYPEDN
-43 (Daiwa Scientific Co., Ltd.), 150 ° C, 500
Even if a time environment resistance test is performed, the pitch shift is 0.05%
It was below.

(Example 5) As a starting material, an etcher flex (Mitsui Toatsu Kagaku) having an underlying copper layer of 0.25 μm thickness formed by sputtering on a polyimide resin film having the same size and thickness as in Example 1 was used. (Manufactured by Co., Ltd.), a substrate having a thickness adjusted to 1 μm by electrolytic copper plating was used, and each treatment was performed in the same manner as in Example 1 except that a bumped tape was obtained in the same manner as in Example 1. It was possible to manufacture. When the height of the bump was measured by an optical step measuring machine, the accuracy was ± 5 μm. Also, after mounting this tape with bumps, blower incubator T
Using YPEDN-43 (Yamato Scientific Co., Ltd.), 150
Even after an environment resistance test at 500 ° C. for 500 hours, the pitch deviation was 0.05% or less.

[0044]

According to the method of the present invention, the TAB can be manufactured by applying a commonly known method for manufacturing a two-layer TAB.
When connecting the tape and the external circuit, it is possible to inspect after mounting without directly bonding the TAB tape and the external circuit. In addition, bumps with bumps with excellent dimensional stability that support multiple pins and narrow pitches. The tape can be reliably manufactured, and it is possible to provide a high-performance electronic component that is economically and industrially excellent.

[Brief description of drawings]

FIG. 1 is a cross-sectional view when an external circuit, a bumped tape, and a TAB tape are connected.

FIG. 2 is a process explanatory view showing the outline of a method for manufacturing a bumped tape in order.

FIG. 3 is a partial plan view showing an appearance showing an example of a tape with bumps obtained by the present invention.

FIG. 4 is a diagram showing an example of a photomask for forming holes and circuit patterns used in the present invention.

FIG. 5 is a diagram showing an example of a photomask for forming various hole patterns used in the present invention.

[Explanation of symbols]

 1 Upper surface metal layer 2 Polyimide resin base 3 Photosensitive resist layer 4 Photosensitive resist layer 5 Resist pattern 6 Land 7 Resist pattern 8 Organic resin coating layer 9 Blind hole 10 Tooling hole 11 Organic resin coating layer 12 Bump 13 TAB tape 14 External circuit 15 electrode pad

Claims (1)

[Claims] 1. A polyimide resin film having a metal layer directly formed on the upper surface thereof as a substrate, a photosensitive resist layer is formed on the upper surface and the lower surface of the substrate having the metal layer, and then a predetermined resist layer is formed on the upper surface of the substrate. Photomask with the land and circuit pattern of No. 2, and the resist layer on the lower surface of the substrate is provided with a photomask having various predetermined hole patterns, the upper surface and the lower surface of the substrate are irradiated with light, and then the resist on the upper surface of the substrate is developed. First step of forming a resist pattern on the upper surface of the substrate, a metal plating layer is laminated on the exposed metal layer according to the resist pattern formed on the upper surface of the substrate by electroplating, and then the resist layer on the upper surface of the substrate is dissolved and removed. To form lands and circuit patterns on the upper surface of the substrate, and then develop the resist on the lower surface of the substrate. Second step of forming a resist pattern on the lower surface of the substrate, and then forming an organic resin film over the entire upper surface of the substrate, by dissolving and removing the exposed polyimide resin in accordance with the resist pattern formed on the lower surface of the substrate to a predetermined portion. Third step of forming predetermined various holes, only specific holes among the various holes formed on the lower surface of the substrate are covered with the organic resin coating, and then various holes formed on the lower surface of the substrate are coated with the organic resin coating. Fourth step of forming a predetermined bump in an unetched hole by electroplating, removing the organic resin coating on the upper and lower surfaces of the substrate, and then dissolving and removing the metal layer directly formed on the upper surface of the substrate A method of manufacturing a tape with bumps, which comprises the steps of: