JPH04330746A - Manufacture of two-layer tab - Google Patents

Abstract

PURPOSE:To enhance the production yield of the title two-layer TAB without lowering its production efficiency by a method wherein a prescribed similar via hole which is worked to be the same as the via hole of the two-layer TAB is made in a prescribed position outside the region of a prescribed two-layer TAB pattern. CONSTITUTION:A photomask which is provided with a desired lead pattern and desired land patterns 15 is executed to a resist layer formed on a surface metal layer; an exposure operation is performed; after that, a developing operation is performed; and a resist pattern is formed on the metal layer. A photomask which is provided with via-hole patterns 16 and pseudo-via-hole patterns 17 is executed to a resist layer formed on a rearsurface resin; an exposure operation is performed; and after that, a developing operation is performed; a resist pattern is formed. By this operation, the resist pattern which has revealed the resin only in prescribed parts in which via holes and pseudo-via holes are to be formed can be formed on the rear surface of a substrate.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is implemented in electronic components2.
Regarding the manufacturing method of the layer TAB, in more detail, a predetermined metal lead is formed on the top surface of the base, a metal layer for grounding is formed on the bottom surface of the base, and further a part of the lead formed on the top surface of the base and a metal layer is formed on the bottom surface of the base. The present invention relates to a method for manufacturing a two-layer TAB having a structure in which a metal layer for grounding is electrically connected to a grounding metal layer through a via hole formed in the insulating resin substrate.

0002

[Background 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.

[0003] TAB is a tape-shaped synthetic resin substrate with electrical insulation properties such as a polyimide resin film, on which a large number of fine metal lead patterns for bonding are formed. Because of this, bonding defects and chip defects can be detected after bonding before mounting on the board, and compared to wire bonding, the size of the IC pad can be smaller, making it possible to increase the number of pins. .

[0004]Currently, the mainstream TAB is a three-layer TAB, which has a structure in which a resin film is laminated with copper foil using an adhesive. The reality is that these properties cannot be fully demonstrated due to the influence of the adhesive used as the intermediate layer. On the other hand, with two-layer TAB, a metal layer is directly formed on the surface of the resin film by sputtering, vacuum deposition, plating, etc. without using an adhesive, so it is possible to avoid performance deterioration due to the use of adhesive. It has advantages and therefore its future potential is expected.

[0005] As described above, this two-layer TAB is produced by forming a metal layer on a resin film using a dry surface treatment method such as a sputtering method or a vacuum evaporation method, or a wet surface treatment method such as an electroless plating method. It is manufactured using a combination of resist patterning technology, electroplating technology, and resin melting technology, using a material as a starting substrate. As mentioned above, it has been confirmed that the two-layer TAB manufactured in this way has higher performance than the conventional three-layer TAB, but in recent years the device packaging density has increased. With the advancement of technology and further increase in processing speed, there is a desire for a two-layer TAB with functions such as prevention of malfunctions due to crosstalk and impedance matching.

[0006] As a two-layer TAB with these functions added, a metal layer for grounding is formed on the surface opposite to the surface on which the leads are formed, via holes are bored in the resin base, and the leads are connected through the via holes. A two-layer TAB has been proposed that has a structure in which the ground metal layer and the ground metal layer are electrically connected.

The outline of the method for manufacturing the two-layer TAB proposed above is as follows. That is, first, a metal layer such as copper is formed on an insulating resin substrate such as polyimide without using an adhesive. Next, photosensitive resist layers are formed on both sides of the substrate, and a resist pattern for forming leads is formed on the upper surface of the substrate, and a resist pattern for forming via holes is formed on the lower surface of the substrate. For forming the leads, either an additive method or a subtractive method is employed depending on the thickness of the metal layer previously formed on the base.

The via holes are formed by melting the exposed insulating resin according to a resist pattern formed on the surface of the base body opposite to the surface on which the leads are formed. The insulating resin can be melted by a wet method using a solution capable of dissolving the resin used, or by an optical method using excimer laser irradiation. After that, a metal layer is formed over the entire bottom surface of the substrate, and by this operation, the side surface of the previously formed via hole can be metalized to establish electrical conduction between the lead on the top surface of the substrate and the ground metal layer on the bottom surface of the substrate, which will be formed later. Either the dry metal forming method or the wet metal forming method described above can be applied to form this metal layer.

[0009] Furthermore, a resist layer is formed on the lower surface of the substrate, or
Immediately after forming the metal layer on the lower surface of the substrate, a plated metal layer is formed by electroplating or the like, and then a resist layer is formed. Subsequently, a photomask having a predetermined hole pattern such as device holes, OLB holes, sprocket holes, tooling holes, etc. is applied to the lower surface of the substrate, and exposure and development are performed to form a predetermined resist pattern. In addition, if a resist layer is formed immediately after forming a metal layer on the bottom surface of the substrate, the desired pattern can be formed using the additive method, or if a plating metal layer is laminated after forming the metal layer on the bottom surface of the substrate, the desired pattern can be formed using the subtractive method. A grounding metal layer can be formed.

0010

[Problems to be Solved by the Invention] However, in manufacturing a two-layer TAB that has the above-mentioned ground metal layer and further conducts the lead and the ground metal layer through a via hole, it is difficult to ensure that the via hole is formed by melting the insulating resin. However, when using the wet method described above, the dissolution time of the resin may vary depending on the history of the solution used to dissolve the insulating resin, and when a large number of via holes are to be formed, the dissolution time may vary depending on the history of the solution used to dissolve the insulating resin. There is a problem in that the via hole is processed without completely forming a conductive hole due to the generation of undissolved holes, and as a result, there is no conduction between the lead and the ground metal layer.

[0011] To avoid the above-mentioned problems, after melting the insulating resin, a visual inspection can be performed to confirm whether each prescribed via hole is formed in a perfect shape. Since the particles are extremely minute, measuring tens to hundreds of μm, 100% inspection using a microscope, etc. may improve manufacturing yield, but it will significantly reduce production efficiency, so it is not an effective method. Hard to say. Therefore, it is desired to develop a new manufacturing method that can improve manufacturing yield without reducing production efficiency.

0012

[Means for Solving the Problems] The present invention has been carried out to meet the above-mentioned needs, and uses an insulating resin base on which a metal layer is formed on one or both sides of the base without using an adhesive. Using the base as a starting material, predetermined metal leads are formed on the top surface of the base, a metal layer for grounding is formed on the bottom surface of the base, and a part of the leads formed on the top surface of the base and a metal layer are formed on the bottom surface of the base. When manufacturing a two-layer TAB having a structure in which a metal layer for grounding is electrically connected to the grounding metal layer through a via hole formed in the insulating resin base, a metal layer for grounding is placed at a predetermined position outside the area of a predetermined two-layer TAB pattern. , characterized in that a predetermined similar via hole is provided which is processed to be equivalent to the via hole of the two-layer TAB.
This is a method for manufacturing layer TAB.

That is, as described above, the present invention provides the desired TA
A predetermined hole (hereinafter referred to as a pseudo-via hole) is formed outside the area of the B pattern, and by inspecting this pseudo-via hole, the degree of dissolution of the insulating resin is ascertained, and the two-layer T
This is to confirm whether the via holes that should originally be formed in the AB have been smoothly and completely formed by melting the insulating resin, and this makes the production of the two-layer TAB more efficient.
Moreover, it can be carried out with high yield.

[0014]

[Function] Next, details of the method for manufacturing a two-layer TAB according to the present invention and its function will be explained based on the drawings.

FIG. 1 shows a two-layer TAB manufactured according to the present invention.
FIG. 3 is a partial plan view showing the appearance of an example of the device. Figure 2
2A and 2B are explanatory diagrams sequentially illustrating the outline of the processing steps when manufacturing a two-layer TAB according to the present invention, and are sectional views of a portion corresponding to the X-Y cross section in FIG. 1. FIG. FIG. 3 shows an example of a lead pattern mask applied to the upper surface of the substrate in the method for manufacturing a two-layer TAB according to the present invention. FIG. 4 shows an example of a via hole pattern and a pseudo via hole pattern mask applied to the lower surface of a substrate in the method for manufacturing a two-layer TAB according to the present invention. 5 and 6 show an example of a photomask for forming device holes, OLB holes, sprocket holes, and tooling holes on the lower surface of a substrate in the method for manufacturing a two-layer TAB according to the present invention.

In FIG. 2, 1 is a lead formed on the upper surface of the substrate by a conventional method, 2 is a resist layer formed on the lower surface of the substrate, and 3 is a polyimide resin substrate.

[0017] There are two methods for forming leads by the conventional method, an additive method and a subtractive method. In the case of using the additive method, a resist layer (not shown) with a desired thickness is formed on the base metal layer (not shown) formed on the upper surface of the substrate 3, and then exposed and developed using a photomask having a lead pattern. A metal plating layer is deposited by electroplating on the exposed base metal layer according to the resist pattern obtained by the process, and the resist formed by the resist pattern and the base metal layer underneath are dissolved and removed to make each lead electrically independent. It is to be formed.

In the case of using the subtractive method, a metal layer with a desired thickness is formed on the upper surface of the substrate 3 in advance, a resist layer is formed on the metal layer, and a photomask having a lead pattern is applied. In this method, leads are formed by dissolving and removing the exposed metal layer according to a lead pattern obtained by exposure and development, and then the resist remaining on the leads is removed.

4 is a resist pattern obtained by applying a photomask having a via hole pattern and a pseudo via hole pattern as shown in FIG. 4 to the resist layer 2 formed on the lower surface of the substrate, exposing and developing the photomask. 5 is a via hole formed by dissolving and removing the exposed portion of the polyimide resin substrate 3 exposed by the resist pattern 4 formed on the lower surface of the substrate, and 6 is a pseudo via hole formed by the same procedure as above.

7 is a metal thin film layer formed over the entire bottom surface after removing the resist pattern 4 on the bottom surface of the substrate, and 8 is a resist layer formed on the metal thin film layer 7. 9 is a resist pattern formed by exposing and developing the photomask shown in FIG. 5 or 6 on the resist layer 8; 10 is a metal plating layer formed on the metal thin film layer 7 exposed by forming the resist pattern 9; be.

Reference numeral 11 denotes a ground metal layer formed by dissolving and removing the resist pattern 9 on the lower surface of the substrate and the metal thin film layer 7 thereunder. 12, 13 and 14 are polyimide resin bases 3 exposed by forming the ground metal layer, respectively.
A device hole formed by dissolving and removing the exposed part of OL
The B hole is the sprocket hole.

15 in FIG. 3 is a land pattern corresponding to a pseudo via hole. In FIG. 4, reference numeral 16 indicates a via hole pattern provided to correspond to a lead formed on the upper surface of the substrate, and reference numeral 17 indicates a pseudo via hole pattern corresponding to a land formed on the upper surface of the substrate.

Next, a method for manufacturing a two-layer TAB according to the present invention will be explained based on the drawings.

[0024] In the present invention, basically a tape-shaped film is used as the substrate 3, which is a polyimide resin with a metal layer adhered to one or both sides without an adhesive.

[0025] Below, a description will be given of a base made of polyimide resin with a metal layer coated on one side, but a detailed explanation of the base with metal layers coated on both sides will be omitted since there is no major difference in procedure from one side. do.

The metal layer to be formed on the upper surface of the polyimide resin substrate 3 may be formed on the surface of the substrate by sputtering, vacuum evaporation, or electroless plating, or by a combination of these methods. The method may be further combined with an electrolytic plating method, and in short, any method can be employed as long as it forms a metal layer directly on the polyimide substrate without applying an adhesive.

Further, copper is generally used as the metal layer formed on the substrate 3 from the viewpoint of electrical performance and cost, but even if a thin film layer of chromium, nickel, etc. is present between the substrate 3 and the copper, there will be no problem. No problem. If the lead is formed by a semi-additive method, the thickness of the metal layer formed on the top surface of the substrate must be thick enough to withstand soft etching during the plating pre-treatment during the formation of the metal electroplated layer before forming the lead. Although there is no particular limitation, the thickness may be 0.5 to 2μ in view of the workability of the partial melting process of the top metal layer for independent wiring as described later.
The range is preferably m.

When leads are formed by a subtractive method, the thickness of the upper metal layer must be made equal to the desired wiring thickness before the resist layer is formed. Therefore, it is best to build up the metal layer by first forming a metal thin film layer on the top surface of the insulating resin substrate using the sputtering method described above, and then depositing a plated metal layer on the top surface to a predetermined thickness by electroplating. . Typically required lead thicknesses are up to about 35 μm.

The thickness of the resist layer formed on the top surface of the substrate needs to be greater than 35 μm since the lead thickness is required to be 35 μm or more when the leads are formed by a semi-additive method. be. Further, when the lead is formed by a subtractive method, there is no particular restriction on the thickness, but considering the pattern accuracy after melting the metal layer, it is appropriate to set it to about 1 to 10 μm.

[0030] The type of resist may be commercially available as long as it can be applied to the above thickness and can withstand the electroplating or dissolution of the metal layer and plating solution that is carried out when forming leads on the top surface. By adding a photosensitive functional group to an acrylic resin, etc., the light-irradiated area remains as an undissolved area during development, or by adding a photosensitive functional group to a novolak resin, etc., the light-irradiated area can be removed. There is a positive resist in which the resist is dissolved during development, but any type of resist can be used. In addition, either a liquid state or a solidified dry film can be used.

The solution for dissolving the metal layer is generally 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 peroxide solution. etc. are used, so the resist only needs to be able to withstand these solutions. In addition, an alkaline solution is sometimes used as the dissolving solution, and in this case, an alkali-resistant resist is used.

The resist layer formed on the resin on the bottom surface of the substrate may be of any material as long as it can withstand the dissolution of the resin in the subsequent steps, but since a strong alkaline material is usually used to dissolve polyimide resin, rubber It is recommended to use a series resist.

Next, a photomask having a desired lead pattern and land pattern 15 as shown in FIG. 3 is applied to the resist layer formed on the upper metal layer, and after exposure, development is performed to form a resist on the metal layer. A resist pattern 4 is formed by applying a photomask having a via hole pattern 16 and a pseudo via hole pattern 17 as shown in FIG. Through this operation, the resist pattern 4 exposes the resin only in the predetermined portions where via holes and pseudo-via holes are to be formed on the lower surface of the substrate.
can be formed.

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 glass or a translucent plastic film.

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

The leads are formed on the upper surface of the substrate by a conventional method using a semi-additive method or a subtractive method.

After forming the leads, the entire upper surface of the substrate may be covered with an organic resin film (not shown). The coating with this organic resin film has the role of protecting the polyimide resin exposed on the surface by the subsequent dissolution of the polyimide resin, and organic resins used for this include rubber-based, epoxy-based, and silicon-based organic resins. You can use .

Subsequently, the resin portion exposed on the lower surface of the substrate is melted to form predetermined via holes 5 and pseudo via holes 6. The pseudo via hole 6 formed according to this via hole pattern 17 has nothing to do with the original performance of the two-layer TAB, so there are no restrictions on its shape or size, but it dissolves the polyimide resin exposed by the resist pattern 4 formed on the bottom surface of the base. Since the formation state of the via hole 5 is to be checked after the process, it is necessary that the size is such that the state can be easily determined visually. Therefore, the size of the pseudo via hole is 100 μm or more in diameter, preferably 500 μm or more in diameter.
It is desirable that the thickness is μm or more. Regarding the shape, it is a perfect circle,
Possible shapes include ellipses, squares, and rectangles.

When forming the via hole 5 by chemically dissolving the polyimide resin, the base body 3 is immersed in a solution and the resin is dissolved until it reaches the back surface of the lead 1, thereby forming a through hole in the base body 3. However, the time required to form a through hole varies depending on the history of the solution, that is, the amount of resin dissolved in the solution, and when a large number of via holes are to be formed, the time required to form a through hole varies depending on the location on the base 3. Even if the melting conditions for the polyimide resin are standardized, such as by varying the time, the yield for forming via holes may decrease significantly. Currently, the best way to ensure that via holes are formed is to visually check the via holes after they are formed.

However, since the diameter of many via holes formed in the base 3 in a two-layer TAB is generally small, about 50 to 100 μm, a microscope or the like must be used for checking, and these must be inspected one by one. Not only does this increase the number of man-hours, but the work is extremely time-consuming. The formation of the pseudo via hole 6 according to the present invention makes it possible to easily grasp the formation status of the via hole 5 by inspecting the pseudo via hole 6 instead of inspecting the formation status of the via hole 5 one by one as described above. be.

To dissolve the polyimide resin, strong alkaline solutions such as hydrazine hydrate and alkali hydroxide are used alone or in combination, and methyl alcohol, ethyl alcohol,
This is done using a solution mixed with propyl alcohol, etc.

Next, after removing the resist pattern 4 on the bottom surface of the substrate, the exposed resin portions on the bottom surface of the substrate including the side surfaces of the via holes 5 and pseudo via holes 6 are metalized using a conductive treatment method, and a metal thin film layer is formed over the entire bottom surface of the substrate. form 7.

In forming the metal thin film layer 7, any of dry metal deposition methods such as sputtering, vacuum evaporation, etc., and wet metal deposition methods such as electroless plating can be employed.

Furthermore, a resist layer 8 is formed on the metal thin film layer 7 on the lower surface of the substrate, and a photomask having various predetermined hole patterns as shown in FIG. 5 or 6 is applied, exposed and developed to form a predetermined resist. Obtain pattern 9. The photomask used here is an example in which a negative photoresist is used to form the resist layer 8 in FIG. 5, and a positive photoresist is used in FIG. A pattern corresponding to the above may or may not be provided.

A plated metal layer 10 is formed on the lower surface of the substrate by laminating a metal electroplating layer on the exposed portion of the metal thin film layer 7 created by forming the resist pattern 9 as described above. By removing the resist formed by the pattern 9 and then dissolving and removing the exposed portion of the metal thin film layer 7 existing thereunder, a two-layer TAB having the ground metal layer 11 on the lower surface of the substrate can be obtained.

When the ground metal layer 11 is formed by a subtractive method, a plated metal layer is first formed on the metal thin film layer 7 by electroplating, and then a resist layer is formed thereon, and exposed and developed. After forming a resist pattern, the exposed portion of the plated metal layer and the underlying metal thin film layer 7 are dissolved to obtain a two-layer TAB having a ground layer on the lower surface of the substrate.

Note that the resist used in this step may be the same as that used previously on the upper surface of the substrate. Further, the exposure and development procedures for forming the resist pattern may be performed in accordance with the procedure for forming the resist pattern previously performed. Finally, the resin part exposed on the bottom surface of the base is melted and the device holes 12 and O
By forming the LB hole 13, sprocket hole 14, and tooling hole (not shown), it is possible to obtain a two-layer TAB in which a predetermined lead on the upper surface and a ground metal layer on the lower surface are electrically connected through the via hole.

[0048]

[Example] Next, an example of the present invention will be described.

Example 1 Copper sulfate 10 g/l and EDTA were applied to the upper surface of a polyimide resin film substrate (manufactured by DuPont-Toray, Kapton 200H, thickness 50 μm) with a size of 15 cm x 15 cm.
60g/l, formalin 6ml/l, dipyridyl 30m
7 with pH 12.5 using an electroless copper plating solution having a composition of 0.5 g/l and 0.5 g/l of polyethylene glycol.
After immersion treatment at 0°C for 10 minutes to form an electroless copper coating, copper sulfate 100 g/l and sulfuric acid 18
Electrolysis was carried out at a current density of 2 A/dm 2 using an electrolytic copper plating solution having a composition of 0 g/l to form a base metal layer of copper with a thickness of 1 μm on the upper surface.

Next, PMER・HC600 (
Apply FSR (manufactured by Tokyo Ohka Co., Ltd., negative photoresist) to a thickness of approximately 40 μm and FSR (manufactured by Fuji Pharmaceutical Co., Ltd., negative photoresist) to the bottom surface of the substrate using a bar coater, and dry at 70°C for 30 minutes. After processing, the upper resist layer has a size of 70 mm x 70 mm, an inner lead pitch of 160 μm, a lead width of 80 μm, and a number of leads of 244.
A glass photomask in which a TAB pattern with eight sprocket holes at each end and one tooling hole at each corner was arranged according to the photomask pattern in Figure 3 was placed in close contact with the resist surface and exposed to 900 mJ of ultraviolet rays. was irradiated.

A photomask having 122 via holes corresponding to the TAB pattern on the upper surface and 3 pseudo via hole patterns each having a diameter of 800 μm corresponding to the above-mentioned land pattern was closely attached to the resist layer on the lower surface.
Exposure was performed by irradiating mJ of ultraviolet light. An ultra-high pressure mercury lamp (manufactured by Oak Seisakusho Co., Ltd.) was used for ultraviolet irradiation. Next, the upper resist layer was developed at 25° C. for 7 minutes using a PMER developer (manufactured by Tokyo Ohka Co., Ltd.) to obtain a predetermined lead pattern, and then dried at 110° C. for 30 minutes. Subsequently, electrolysis was carried out on the exposed upper surface of the base copper layer using the electrolytic copper plating solution described above at a current density of 2 A/dm2 for 50 minutes to form a lead preform made of copper with a thickness of about 35 μm.

Next, the resist layer on the lower surface was developed using FSR-D (manufactured by Fuji Pharmaceutical Co., Ltd.) at 25° C. for 50 seconds to obtain a 122
After obtaining a resist pattern having 3 predetermined via hole patterns and 3 pseudo via hole patterns,
Then, the resist on the top surface was treated with a 4% sodium hydroxide solution at 50°C for 1 minute to remove the resist, and the underlying copper layer on the top surface was treated with a 4% sodium hydroxide solution at 100 g/l of copper chloride.
, ammonium chloride 100g/l, ammonium carbonate 2
0g/l, ammonia water 400ml/l to make each lead independent by dissolving it in an ammonia-based alkaline solution with a composition of 400ml/l,
Next, using FSR (manufactured by Fuji Pharmaceutical Co., Ltd.) as an organic film agent, it was applied to a thickness of approximately 10 μm over the entire upper surface of the substrate.
Organic film coating was performed by drying at 0° C. for 30 minutes.

Next, ethyl alcohol and potassium hydroxide 1
Using a mixture of standard solutions at a volume ratio of 1:1, heat at 50°C.
When the pseudo via hole formed by dipping the substrate for 5 minutes to dissolve the exposed portion of the polyimide resin on the lower surface of the substrate was inspected, no undissolved polyimide resin was found. Furthermore, when all 122 via holes were inspected, no undissolved polyimide resin was found, and a correlation between the formation state of the pseudo via hole and the via hole was observed. next,
The remaining FSR was removed by treatment at 70° C. for 15 minutes using an FSR stripping solution (manufactured by Fuji Pharmaceutical Co., Ltd.).

Next, a copper thin film layer is formed over the entire lower surface using the electroless copper plating solution described above, and PMER/
Apply HC600 (manufactured by Tokyo Ohka Co., Ltd., negative photoresist) to a thickness of about 20 μm using a bar coater,
It was dried at ℃ for 30 minutes.

On this resist, there is one device hole corresponding to the TAB pattern used in the previous exposure process;
Upper base 22m at symmetrical positions with respect to the center of the pattern
m, trapezoid-shaped OLB with a bottom base of 32 mm and a height of 5 mm.
4 holes, 2mm x equally spaced on both sides of the TAB pattern
Eight 3mm rectangular sprocket holes are arranged on one side, and square tooling holes with a side of 2mm are placed at four locations within the TAB pattern area on a straight line extending from the center of the TAB pattern to each vertex of the device hole. 4
A photomask having various hole patterns formed by arranging the resists was irradiated with 400 mJ of ultraviolet rays, treated with the aforementioned developer at 25°C for 3 minutes, and then dried at 110°C for 30 minutes to form the desired resist. I got the pattern.

Next, electrolysis is carried out for 20 minutes at a current density of 2 A/dm2 using the electrolytic copper plating solution described above to form a copper ground layer of about 18 μm on the exposed copper thin film layer on the bottom surface, which remains on the bottom surface. The resist was removed by treatment in a 4% sodium hydroxide solution at 50° C. for 1 minute.

Next, the copper thin film layer existing under the resist on the bottom surface is treated with a 200 g/l solution of copper chloride at 50° C. for 30 seconds to dissolve and remove the copper thin film layer on the bottom surface of the substrate, removing via holes. After exposing the polyimide resin in portions corresponding to the various holes, the exposed polyimide resin was dissolved and removed using the aforementioned polyimide solution to form various holes.

Finally, the organic resin film on the top surface of the substrate is peeled off using FSR stripping liquid (manufactured by Fuji Pharmaceutical Co., Ltd.) at 70° C. for 15 minutes, and the lead portion in a predetermined pattern is formed on the top surface, and the lead portion on the bottom surface is removed. It was possible to obtain a two-layer TAB that had a copper ground metal layer on the top and the upper and lower metal parts were electrically connected through via holes.

Example 2 A copper plating film was formed on the upper surface of the same polyimide resin film-like substrate as in Example 1 by the above-mentioned electroless copper plating, and then a 1 μm thick film was formed on the upper surface by the above-mentioned electrolytic copper plating.
A base copper metal layer of m was formed.

Next, steps similar to those in Example 1 were carried out, including the formation of a resist layer on the lower surface and the formation of an organic resin film over the entire upper surface of the substrate.

Next, the exposed polyimide resin was dissolved by immersing the lower surface at 50° C. for 4 minutes in a mixture of ethyl alcohol and 1N potassium hydroxide solution in a volume ratio of 1:1. When the three pseudo via holes thus formed were inspected, it was confirmed that two of the three pseudo via holes had undissolved polyimide.

Next, when all 122 via holes were inspected, it was confirmed that there was undissolved polyimide resin in 101 of the 122 via holes. The subsequent steps after removing the residual resist on the bottom surface of the substrate were carried out in the same manner as in Example 1, and when the conductivity between the leads of the obtained two-layer TAB and the ground metal layer was inspected, it was found that the unmelted polyimide resin was first detected. The 101 via holes in which it was confirmed were not electrically connected.

[0063]

[Effects of the Invention] As described above, when using the method for manufacturing a two-layer TAB of the present invention, it is possible to easily understand the formation status of the original via hole by observing the pseudo via hole, and the ground metal layer is It becomes possible to manufacture a two-layer TAB having a structure in which the lead on the top surface and the ground metal layer are electrically connected through the via hole with high production efficiency and good yield.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of the external appearance of an example of a two-layer TAB obtained according to the present invention.

FIG. 2 is an explanatory diagram illustrating the outline of processing steps (A) to (G) in order when manufacturing a two-layer TAB according to the present invention.

FIG. 3 is a plan view showing an example of a lead pattern mask applied to the upper surface of a substrate in the method for manufacturing a two-layer TAB according to the present invention.

FIG. 4 is a plan view showing an example of a via hole pattern and a pseudo via hole pattern mask applied to the lower surface of a substrate in the method for manufacturing a two-layer TAB according to the present invention.

FIG. 5: In the method for manufacturing a two-layer TAB according to the present invention,
FIG. 3 is a plan view showing an example of a photomask used to form a device hole, an OLB hole, a sprocket hole, and a tooling hole on the lower surface of the base.

FIG. 6: In the method for manufacturing a two-layer TAB according to the present invention,
FIG. 7 is a plan view showing another example of a photomask used to form a device hole, an OLB hole, a sprocket hole, and a tooling hole on the lower surface of the base.

[Explanation of symbols]

1 Lead 2 Resist layer 3 Polyimide resin base 4 Resist pattern 5 Beer hall 6. Pseudo beer hall 7 Metal thin film layer 8 Resist layer 9 Resist pattern 10 Metal plating layer 11 Ground metal layer 12 Device hole 13 OLB Hall 14 Sprocket hole 15 Land pattern 16 Via hole pattern 17 Pseudo via hole pattern

Claims (1)

[Claims] [Claim 1] The base is an insulating resin base with a metal layer formed on one or both sides of the base without using an adhesive, and using the base as a starting material, predetermined metal leads are formed on the top surface of the base, and the base is A grounding metal layer is formed on the bottom surface of the substrate, and a portion of the lead formed on the top surface of the substrate and a grounding metal layer formed on the bottom surface of the substrate are electrically connected through via holes formed in the insulating resin substrate. A method for manufacturing a two-layer TAB having a conductive structure, characterized in that a predetermined similar via hole that is processed to be equivalent to the via hole of the two-layer TAB is provided at a predetermined position outside the area of a predetermined two-layer TAB pattern. A method for manufacturing a two-layer TAB.