JP3186834B2 - Etching solution for dissolving polyimide resin and method for etching through hole using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching solution for a polyimide resin and a method for etching a polyimide resin substrate having a two-layer structure using the same.

[0002]

2. Description of the Related Art Hitherto, polyimide resins have been used in various applications because of their excellent heat resistance, dimensional stability, chemical resistance, electrical properties and mechanical properties. Examples include film carriers used for flexible printed wiring boards and automatic tape bonding (TAB).

Conventionally, when a film carrier is formed using a polyimide resin film as a substrate, a through hole such as a device hole for connecting an IC element is formed in the polyimide resin substrate by press working, and then the film carrier is formed. A so-called three-layer structure type substrate in which a copper foil is adhered to the substrate with an adhesive has been mainly used. However, recently, the heat resistance of the epoxy resin used as an adhesive in the above three-layer structure substrate is remarkably inferior to that of the polyimide resin, and one of the features of the film carrier using the polyimide resin substrate is high heat resistance. From the viewpoint of impairing the performance, a two-layer structure type substrate in which a copper foil is directly adhered to a polyimide resin substrate without an adhesive has been developed.

[0004] Unlike a TAB having a three-layer structure substrate, a film carrier (hereinafter, referred to as a TAB) mainly having a two-layer structure substrate has copper directly deposited on a polyimide resin film in advance. Therefore, a desired through-hole cannot be selectively formed in the polyimide resin substrate by press working.

[0005] Therefore, in the two-layer structure TAB, a resist is preliminarily applied to the polyimide resin substrate, and a patterning process is performed so that only a desired through-hole opening position is exposed. A chemical dissolving treatment method of performing a hole opening treatment using a chemical etching solution that does not dissolve the compound is adopted.

Conventionally, a mixed solution of potassium hydroxide and ethanol (Japanese Patent Application Laid-Open No. 58-103531) and a hydrazine solution (Japanese Patent Publication No. Sho 45) have been used as an etchant for a polyimide resin.
-40800), a mixed solution of hydrazine and ammonia (JP-A-50-4577), a mixed solution of hydrazine and ethylenediamine (JP-A-51-22071), (JP-A-51-27464), hydrazine and amide Compound (JP-A-53-49068), tetramethylammonium hydroxide and an amine compound (JP-A-57-65727).
), An alcoholic solution of tetramethylammonium hydroxide (JP-A-58-74041), tetramethylammonium hydroxide with an amide compound and an amine compound (JP-A-58-96632).

[0007]

However, sodium hydroxide, potassium hydroxide, and the like, which are frequently used as alkali hydroxides, alone have a low etching rate at around room temperature and have a low etching rate of several tens of μm. It takes several hours to etch and is not suitable.

It is difficult to completely dissolve and remove the necessary portion of the polyimide even if the etching rate is increased by using a high temperature and a high concentration, and when such severe conditions are selected, fine precision is required. Processing of simple through holes is not possible.

A hydrazine solution has been used to form a through hole in a polyimide resin. However, the hydrazine solution alone etches the polyimide resin with a long incubation period until the start of etching. Infiltration into the resin film and subsequent rapid etching may cause so-called over-etching, which dissolves to the point where the polyimide resin does not need to be etched.As a result, fine through-holes of desired dimensions and shapes can be formed. Therefore, it is not suitable for applications requiring a highly accurate shape for the through-hole.

Therefore, as a method of shortening the incubation period,
An etching method using a mixed solution to which an amine compound has been added has been proposed. When a mixed solution of hydrazine and ethylenediamine is used, deformation and swelling of the polyimide resin does not occur, and the etching rate increases linearly with an increase in the temperature of the etching solution. However, hydrazine has high hygroscopicity, absorbs moisture and carbon dioxide in the atmosphere, and its purity decreases,
As a result, the etching rate also decreases, so that it is extremely difficult to control the etching rate. Therefore, there is a problem that the etching solution must be frequently updated, which is not economical.

Furthermore, hydrazine is highly toxic and has a problem that inhalation of its vapor causes inflammation of the respiratory tract and circulatory system. When handling a large amount, hydrazine requires a certain protection system and is therefore practical. Also has its drawbacks.
Further, the mixed solution of hydrazine and the amide compound has a disadvantage that etching unevenness easily occurs due to a low etching rate, and as a result, it is not suitable for fine patterning.

[0012] Recently, a relatively low-toxicity etchant such as tetramethylammonium hydroxide has been proposed. However, this etchant has a very low dissolution rate in a polyimide resin. It takes about 120 minutes to completely dissolve the resin, and the working efficiency is poor. In addition, when the above-mentioned conventional etching solution is used, there is a problem that a rubber-based resist or a mask made of a metal film is eroded to cause swelling.

The present invention solves the above-mentioned various problems in the chemical dissolution treatment of a through hole in a polyimide resin substrate, and can efficiently and finely process a fine through hole in a polyimide resin with high dimensional accuracy. An object of the present invention is to provide an etching solution and a method for etching a polyimide resin substrate using the same.

[0014]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that an etchant having the following composition has an excellent effect in achieving the above object. Was found. That is, the etching solution for a polyimide resin of the present invention is: (1) an etching solution having a composition comprising 1 to 40% by weight of an alkali hydroxide, 1 to 20% by weight of a phenol solvent, and the balance water. (2) An etching solution having a composition comprising 1 to 40% by weight of an alkali hydroxide, 1 to 20% by weight of a phenolic solvent, 1 to 30% by weight of an amine compound, and the balance water. (3) An etching solution having a composition of 1 to 40% by weight of an alkali hydroxide, 1 to 20% by weight of a phenolic solvent, 1 to 30% by weight of an amine compound, and the balance of alcohol. And performing a chemical dissolution treatment of the through-holes of the polyimide resin substrate by etching the polyimide resin using any of these three types of etchants. This is a through hole etching method.

[0015]

The etching solution composition according to the present invention comprises a mixed solution comprising two or more kinds of chemicals selected from an alkali hydroxide and an amine compound, a phenolic solvent and an alcohol as described above. The mechanism of etching the polyimide resin of the etching solution of the present invention is such that an alkali hydroxide cuts and cuts an imide ring of the polyimide resin, and forms a hydrogen bond with a polyamic acid that has been degraded by an amine compound, a phenolic solvent, or an alcohol. It is considered that the polyimide resin is converted into a dissolvable structure, thereby effectively performing precise etching of the polyimide resin.

Hereinafter, using the etching solution of the present invention,
An example will be described in which a through hole having a desired rectangular or square shape such as a device hole and a sprocket hole is formed in a polyimide resin substrate in a two-layer structure TAB.

Generally, a polyimide resin substrate having a thickness of about 50 μm is used in the two-layer structure TAB. In order to form a through hole of a desired shape in this polyimide resin substrate, first, a photoresist material is applied to the polyimide resin surface of the two-layer structure TAB, and then a predetermined glass mask material is applied to perform exposure and development. A patterning process so that only a desired portion of the resin surface is exposed, and applying the etchant to the obtained polyimide resin exposed portion to dissolve the portion to form a through hole. It is.

The alkali hydroxide used in the etching solution of the present invention includes sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. The etching rate for the polyimide resin depends on the concentration of the alkali hydroxide, and increases as the concentration increases. When the concentration of the alkali hydroxide is less than 1% by weight, it takes 120 minutes at 60 ° C. to completely dissolve the polyimide resin having a thickness of 50 μm, and the productivity is poor. It is not suitable because the alkali hydroxide in the liquid causes precipitation and the etching rate becomes slow. It is recommended that the particularly preferable concentration of the alkali hydroxide be in the range of 4 to 40% by weight from the viewpoint of the etching ability to the polyimide resin, the solubility of the alkali hydroxide, and the like.

The temperature at which the etching solution is used is not particularly limited. However, if the temperature is too low, the etching rate is reduced and the efficiency is low. If the temperature is too high, the etching solution boils or decomposes. Considering 40 to 8
A range of 0 ° C. is desirable. Especially when the concentration of alkali hydroxide is 4
If the etching temperature is high near 0% by weight and the etching temperature is increased, the etching rate for the polyimide resin becomes extremely high, and there is a risk that the photoresist for forming the through-holes may be eroded and the dimensional accuracy may be deteriorated.

The respective components such as alkali hydroxide constituting the etching solution of the present invention are not suitable for dissolving the polyimide resin alone, and exhibit an excellent etching ability to the polyimide resin only by mixing these components. You can do it. The phenolic solvent used in the present invention includes phenol, aminophenol, o-
Cresol, m-cresol, p-cresol, o-chlorophenol, p-chlorophenol, p-bromophenol, 3,5-xylenol, 2,5-xylenol, 3,4-xylenol, 2,4-xylenol,
Examples thereof include 2,4-dichlorophenol and 2,4,6-trichlorophenol. Among them, phenol, o-cresol, m-cresol, p-cresol, aminophenol and the like are particularly preferable.

When the concentration of the phenolic solvent is less than 1% by weight, the etching rate is low, and it takes 120 minutes at 60 ° C. to completely dissolve the polyimide resin having a thickness of 50 μm. A desired desired shape cannot be obtained when a through hole is opened due to permeation and swelling. If the content is more than 20% by weight, alkali phenol hydroxide is precipitated in the etching solution, which is not preferable from the viewpoint of solubility. Therefore, considering the solubility, the phenol resin concentration in the etching solution is 2
Preferably it is less than 0% by weight.

The amine compound is represented by the general formula NH ₂
-R-NH ₂ (wherein R represents an atomic group containing at least 2 carbon atoms).

Is used, and its structural formula is

Or

## STR2 ##

[0024]

Embedded image (1) R: — (CH ₂ ) _n − (where n is 2
Integer greater than or equal to)

[0025]

## STR2 ## _{(2) R :-( CH 2 ·} CH 2 · NH) n ·
CH ₂ · CH _2- (where n is an integer of 1 or more) Examples of the compound represented by the structural formula of the formula (1) include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like. Compounds. Examples of the compound represented by the structural formula (2) include diethylenetriamine and triethylenetetraamine. Further, two or more of the above polyamine compounds may be selected.

When the concentration of the amine compound is less than 1% by weight, the shape of the opening and its linearity are impaired. Also, when the amount of the amine compound exceeds 30% by weight, not only is the shape and linearity of the through-hole opening portion impaired, but also the exposed copper surface is discolored, which is not preferable.
Considering the etching rate and the shape of the opening of the through hole, the preferred concentration of the amine compound is around 20% by weight.

The alcohol used in the present invention includes, for example, methanol, ethanol, n-propanol, iso-propanol, ethylene glycol and the like. Among them, ethanol is particularly preferred. The alcohol concentration in the etching solution is suitably in the range of 20 to 50% by weight in consideration of the shape of the opening and the etching rate.

As a photoresist material usable as a masking material in the patterning process, a negative type resist such as a cyclized rubber azide type or a cyclized polybutadiene type is preferable. For example, FSR-220 and FMR-150 manufactured by Fuji Pharmaceutical Co., Ltd. OMR-83 manufactured by Tokyo Ohka Kogyo Co., Ltd.
Examples include OMR-85, ODUR and ONNR, NNR-732 and NNR-752 manufactured by Nagase & Co., Ltd., KMER and KTFR manufactured by Kodak Co., Ltd., and CBR-M901 manufactured by Nippon Synthetic Rubber Co., Ltd. of cyclized polybutadiene negative type. .

As the photoresist material applied to the polyimide resin when forming a predetermined through hole, rubber-based photoresist such as bisazide-based cyclized natural rubber or cyclized butadiene rubber is used from the viewpoint of chemical resistance. In addition, a metal coating such as aluminum, nickel, titanium, copper, molybdenum, gold, tungsten, chromium, or a nickel-copper alloy can be used as the masking material.

The thickness of the rubber-based liquid photoresist material or metal film to be formed is desirably 2 μm or more. 2
If the thickness is less than μm, defects such as pinholes are likely to occur in the formed film, and the etchant may penetrate from that location to peel off the photoresist material, which may cause over-etching. On the other hand, if the thickness of the photoresist material is excessively large, the pattern accuracy is reduced, and it takes too much time to form a metal film such as copper. Therefore, the thickness of the photoresist material is 10
It is preferable to keep it to μm or less.

[0031]

Embodiments of the present invention will be described below. Example 1 (Sample preparation method) A sample for a polyimide resin substrate etching test was prepared in the following procedure.

FIG. 1 is an explanatory view showing the order of steps in the case where an exposed portion is provided on a resin surface of a two-layer structure TAB in order to partially etch a desired portion of the polyimide resin surface. In FIG. 1, 1 is a polyimide resin substrate, 2 is a copper layer,
3a is an acid-resistant photoresist film, 3b is an alkali-resistant photoresist film, 4 is a copper plating layer, 5 is an alkali-resistant protective resist film, and 6 is a polyimide resin exposed surface (hole pattern).

As a starting material, a polyimide resin substrate (KAPTON-V manufactured by Du Pont-Toray Co., Ltd.) 1 having a thickness of 50 μm was used, and a two-layer substrate having a 0.6 μm copper layer 2 formed on one surface by a conventional method was used (FIG. 1). (A)).

On the copper layer 2 of the substrate 1, an aliphatic hydrocarbon-based solution-developing acid-resistant photoresist material (OMR-83, manufactured by Tokyo Ohka Kogyo Co., Ltd., viscosity: 600 cps) is spin-coated (MF-895, manufactured by Kuranami Seisakusho). Using 150RPM per minute
M and then dried at 70 ° C for 30 minutes to 20 μm
Is formed on the polyimide resin substrate 1 on the opposite side, and an aliphatic hydrocarbon-based solution developing type alkali-resistant photoresist material (FSR-220 manufactured by Fuji Pharmaceutical Co., Ltd. 220 cps) by a similar spin coater at 70 RPM / min.
After drying for 8 minutes, an alkali-resistant photoresist film 3b having a thickness of 8 μm was formed (FIG. 1B).

Next, the photoresist 3a on the copper layer surface is irradiated with 800 mj of ultraviolet light using a super high pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd.) through a predetermined glass mask to expose the photoresist, and then the polyimide resin on the opposite surface is exposed. The photoresist 3b was also exposed to 400 mj of ultraviolet light through a predetermined glass mask using the same mercury lamp as described above to expose the photoresist. Next, the photoresist 3a on the side of the copper layer 2 is developed with a dedicated developer for 1 minute, then rinsed with a rinsing solution for 1 minute, and then dried at 130 ° C. for 30 minutes so that a desired portion of the copper layer 2 is exposed. A pattern was formed (FIG. 1C).

Next, 100 g / l of copper sulfate and 180 g of sulfuric acid were applied to the exposed copper layer formed on the lead pattern forming surface on the copper layer 2 side.
Using an electrolytic copper plating solution having a composition of g / l and a current density of 2 A / dm ² , performing an electrolytic treatment at a solution temperature of 25 ° C. for 50 minutes to apply a copper plating layer 4,
After drying for 0 minutes, a copper lead having a thickness of 35 μm was formed (FIG. 1D).

Next, the photoresist 3a remaining on the copper layer 2 side is immersed in an OMR stripper (manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 5 minutes to be stripped and removed, and then the photoresist 3b on the polyimide resin substrate 1 side is subjected to FSR development. Liquid (manufactured by Fuji Ohka Kogyo Co., Ltd.) at 23 ° C. for 1 minute, and then rinsed with FSR rinsing solution (manufactured by Fuji Oka Kogyo Co., Ltd.) for 30 seconds.
After drying at 0 ° C. for 20 minutes, the polyimide resin substrate 1
A hole pattern was formed such that an exposed surface 6 was formed at a desired portion of the surface (FIG. 1E).

Next, the copper layer 2 outside the lead pattern formation site was removed with an alkaline etching solution (A
-Dissolution removal by immersion at 25 ° C. for 5 minutes using (process), followed by washing with water and drying at 80 ° C. for 30 minutes. Next, an alkali-resistant protective resist (FMR manufactured by Fuji Pharmaceutical Co., Ltd.) is spin-coated on the lead formation surface at a rotation speed of 70 RPM using the spin coating machine, dried at 70 ° C. for 30 minutes, and applied to the polyimide resin substrate 2 surface. A test sample (32 m) having a polyimide resin exposed surface for forming each through hole of a sprocket hole and a device hole
m × 32 mm) (FIG. 1 (F)). (Etching test) An etching test was performed using a test sample in which a desired polyimide resin exposed portion was formed as described above.

As an etching solution, sodium hydroxide 3
Using a mixed solution having a composition of 0% by weight, phenol 10% by weight, and water 60% by weight, an etching temperature of 60 ° C. and 10%
After immersion for a minute, sprocket holes and device holes were formed in the polyimide resin substrate.

Next, an ultrasonic cleaner (oscillation frequency: 45 KH)
z, output 200 W), ultrasonic wave was applied in trichlorethylene for 10 minutes, and then the dimensional accuracy of each hole pattern formed in the polyimide resin was measured. ６6%. The corners of the sprocket holes had almost no roundness and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through holes was in a good condition without discoloration.

As described above, when each predetermined through-hole is formed in the polyimide resin substrate having the two-layer structure TAB using the etching solution of the present invention, the etching is performed in a relatively short time to obtain a good shape and a good size. This is extremely effective because highly precise fine through holes can be formed. Example 2 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 20% by weight of sodium hydroxide and 5% by weight of phenol were used as an etchant. , Remaining water 7
Using a mixed solution having a composition of 5% by weight, the substrate was immersed at an etching temperature of 60 ° C. for 120 minutes to form through holes in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket hole formed on the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was excellent, ± 5-6% with respect to the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 3 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 5% by weight of sodium hydroxide and 20% by weight of phenol were used as an etchant. , Remaining water 7
Using a mixed solution having a composition of 5% by weight, the substrate was immersed at an etching temperature of 60 ° C. for 15 minutes to form through holes in the polyimide resin substrate in the same manner as in Example 1.

Next, when the dimensional accuracy of the sprocket hole formed in the polyimide resin substrate was measured in the same procedure as in Example 1, the dimensional accuracy was as excellent as ± 5 to 7% with respect to the design mask size. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 4 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 1% by weight of sodium hydroxide and 10% by weight of phenol were used as an etchant. , Balance water 8
Using a mixed solution having a composition of 9% by weight, the substrate was immersed at an etching temperature of 60 ° C. for 18 minutes to form through holes in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket holes formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8%, which was excellent with respect to the design mask dimensions. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 5 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 40% by weight of sodium hydroxide and 1% by weight of phenol were used as an etching solution. , Residual water 5
Using a mixed solution having a composition of 9% by weight, the substrate was immersed at an etching temperature of 60 ° C. for 8 minutes to form through holes in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket hole formed on the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8%, which was excellent with respect to the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 6 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared by the same procedure as in Example 1, and then 30% by weight of sodium hydroxide and 10% by weight of phenol were used as an etchant. Using a mixed solution having a composition consisting of ethylenediamine 20% by weight and a balance of water 40% by weight at an etching temperature of 60 ° C.
After immersion for a minute, a through hole was formed in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket hole formed on the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 3 to 5% of the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 7 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 20% by weight of sodium hydroxide and 10% by weight of phenol were used as an etching solution. Using a mixed solution having a composition of 10% by weight of ethylenediamine and 60% by weight of water at the etching temperature of 60 ° C.
After immersion for a minute, a through hole was formed in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket holes formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was as excellent as ± 4 to 5% with respect to the design mask dimensions. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 8 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 1% by weight of sodium hydroxide and 10% by weight of phenol were used as an etchant. , An ethylenediamine 30% by weight and a balance of water 49% by weight using a mixed solution having a composition of 15% at an etching temperature of 60 ° C.
After immersion for a minute, a through hole was formed in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket holes formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8%, which was excellent with respect to the design mask dimensions. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 9 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared by the same procedure as in Example 1, and then 40% by weight of sodium hydroxide and 1% by weight of phenol were used as an etchant. Using a mixed solution having a composition consisting of 1% by weight of ethylenediamine and the balance of 58% by weight of water, the substrate was immersed at an etching temperature of 60 ° C. for 7 minutes to form through holes in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket hole formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 6 to 7%, which was excellent with respect to the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 10 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 25% by weight of sodium hydroxide and 5% by weight of phenol were used as an etchant. Using a mixed solution having a composition consisting of ethylenediamine, 20% by weight, and the remaining 50% by weight of ethanol, using an etching temperature of 60%.
By immersing at 6 ° C. for 6 minutes, the same through holes as in Example 1 were formed in the polyimide resin substrate.

Next, the dimensional accuracy of the sprocket holes formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was excellent ± 2 to 5% with respect to the design mask size. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 11 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 20% by weight of sodium hydroxide and 20% by weight of phenol were used as an etchant. And an etching temperature of 6 using a mixed solution having a composition comprising:
By dipping at 0 ° C. for 7 minutes, the same through holes as in Example 1 were formed in the polyimide resin substrate.

Next, the dimensional accuracy of the sprocket holes formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was excellent ± 3 to 5% with respect to the design mask dimensions. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 12 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 20% by weight of sodium hydroxide and 10% by weight of phenol were used as an etchant. And an etching temperature of 6 using a mixed solution having a composition comprising:
By immersing at 0 ° C. for 6 minutes, the same through holes as in Example 1 were formed in the polyimide resin substrate.

Next, when the dimensional accuracy of the sprocket hole formed on the polyimide resin substrate was measured in the same procedure as in Example 1, the dimensional accuracy was excellent ± 2 to 5% with respect to the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 13 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 1% by weight of sodium hydroxide and 20% by weight of phenol were used as an etchant. Using a mixed solution having a composition consisting of 10% by weight of ethylenediamine and the balance of 69% by weight of ethanol, using an etching temperature of 60%.
By immersing at 17 ° C. for 17 minutes, through holes were formed in the polyimide resin substrate in the same manner as in Example 1.

Next, the dimensional accuracy of the sprocket hole formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8%, which was excellent with respect to the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 14 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 40% by weight of sodium hydroxide and 10% by weight of phenol were used as an etching solution. Using a mixed solution having a composition consisting of 1% by weight of ethylenediamine and 49% by weight of ethanol as the balance, using an etching temperature of 60%.
By immersing at 8 ° C. for 8 minutes, the same through holes as in Example 1 were formed in the polyimide resin substrate.

Next, the dimensional accuracy of the sprocket hole formed on the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8% of the design mask dimension, which was excellent. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Example 15 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then 10% by weight of sodium hydroxide and 1% by weight of phenol were used as an etchant. And an etching temperature of 60 using a mixed solution having a composition consisting of ethylenediamine 30% by weight and the balance ethanol 59% by weight.
By immersing at 12 ° C. for 12 minutes, the same through holes as in Example 1 were formed in the polyimide resin substrate.

Next, the dimensional accuracy of the sprocket hole formed in the polyimide resin substrate was measured in the same procedure as in Example 1, and the dimensional accuracy was ± 7 to 8% of the design mask dimension. showed that. In addition, the shape of the corners in the sprocket hole was almost non-round and the opening shape was linear, and the surface of the copper layer exposed by the formation of the through hole was in a good condition without discoloration. Comparative Example 1 An etching test sample of a two-layer structure TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then a polyimide was used instead of the etching solution according to the present invention. Sodium hydroxide 4 which is known as an etching solution for resin
The polyimide resin substrate was etched by immersing it at an etching temperature of 60 ° C. for 20 minutes using a mixed solution having a composition of 80% by weight of ethanol, 80% by weight of ethanol and 16% by weight of the remaining water. Was hardly formed.

Next, when the sample was observed with a stereoscopic microscope, it was confirmed that the photoresist formed on the polyimide resin surface was partially eroded and swelled. Comparative Example 2 An etching test sample of a two-layered TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then a polyimide was used instead of the etching solution according to the present invention as an etching solution. Sodium hydroxide 40 known as an etching solution for resin
The polyimide resin substrate was etched by immersing it at an etching temperature of 60 ° C. for 20 minutes using an aqueous solution having a composition of 60% by weight of water and the balance of water was 60% by weight. Under the above etching conditions, through holes were hardly formed. Was.

Next, when the sample was observed using a stereoscopic microscope, it was found that the photoresist formed on the polyimide resin surface was completely peeled off. COMPARATIVE EXAMPLE 3 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then a polyimide was used instead of the etching solution according to the present invention. A polyimide resin substrate was etched by immersion at an etching temperature of 60 ° C. for 20 minutes using a mixed solution having a composition of 30% by weight of tetramethylammonium hydroxide and 70% by weight of methanol, which is known as a resin etching solution. However, through-holes were hardly formed under the above etching conditions.

Next, when the sample was observed using a stereoscopic microscope, it was confirmed that the photoresist formed on the polyimide resin surface had a portion partially eroded. Comparative Example 4 An etching test sample of a two-layer TAB having an exposed portion at a predetermined portion of a polyimide resin substrate was prepared in the same procedure as in Example 1, and then a polyimide was used instead of the etching solution according to the present invention as an etching solution. Using a mixed solution having a composition of 70% by weight of hydrazine and 30% by weight of ethylenediamine, which is known as a resin etching solution, was immersed at an etching temperature of 60 ° C. for 6 minutes. It was found that the same through holes as in Example 1 were formed in the resin substrate.

However, when the dimensional accuracy of the through hole formed in the polyimide resin substrate in the same procedure as in Example 1 was measured, the dimensional accuracy was ± 15 to 30% with respect to the design mask dimension. It was found that over-etching due to side etching was large, and it was clearly impossible to achieve the desired dimensional accuracy. Also, the shape of the corners in the sprocket holes was rounded, and it was also confirmed that the photoresist had swelled.

[0060]

As described above, according to the etching solution of the present invention, even if the polyimide resin substrate forming the film carrier such as the two-layer structure TAB is relatively thick, the etching of the through-hole can be quickly and efficiently formed. Since it is possible and does not erode or swell the photoresist applied during the patterning process as compared with the case of etching with the conventional hydrazine solution, the fine through-hole is accurately and precisely processed with extremely high dimensional accuracy. be able to. In addition, since it is not affected by moisture or carbon dioxide gas in the atmosphere, handling is stable and the advantage is large.

[Brief description of the drawings]

FIG. 1 is an explanatory view of steps (A) to (F) in a case where a patterning process is performed on a polyimide resin substrate in a two-layer structure TAB.

FIG. 2 is a plan view illustrating a through-hole pattern of a two-layer structure TAB.

[Explanation of symbols]

 Reference Signs List 1 polyimide resin substrate 2 copper layer 3a acid-resistant photoresist 3b alkali-resistant photoresist 4 copper plating layer 6 polyimide resin exposed surface (hole pattern) 7 sprocket hole 8 device hole 9 OLB hole 10 conductor pattern 11 lead

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08J 7/02 H01L 21/308 H05K 3/06

Claims (4)

(57) [Claims] 1 to 40% by weight of an alkali hydroxide,
An etching solution for dissolving a polyimide resin having a composition of 20% by weight of a phenol solvent and the balance of water. 2. The method according to claim 1, wherein the alkali hydroxide is 1 to 40% by weight.
An etching solution for dissolving a polyimide resin having a composition consisting of 20% by weight of a phenol solvent, 1 to 30% by weight of an amine compound, and the balance water. 3. An alkali hydroxide of 1 to 40% by weight,
An etching solution for dissolving a polyimide resin having a composition consisting of 20% by weight of a phenolic solvent, 1 to 30% by weight of an amine compound and the balance of alcohol. 4. A method according to claim 1, wherein a patterning process is performed on the polyimide resin substrate in the film carrier using the two-layer polyimide resin substrate, and a chemical dissolution process is performed to form a through hole in a predetermined portion of the resin substrate. A method for etching a through hole in a polyimide resin substrate, wherein the dissolving treatment is performed using the etching solution according to claim 3.