WO2003083581A1

WO2003083581A1 - Resist releasing agent

Info

Publication number: WO2003083581A1
Application number: PCT/JP2003/003824
Authority: WO
Inventors: Yasuji Fujita; Hiroyuki Horikoshi; Toru Arai
Original assignee: Meltex Inc.
Priority date: 2002-03-29
Filing date: 2003-03-27
Publication date: 2003-10-09
Also published as: JP3854523B2; JP2003295476A; CN1533516A; CN1238771C

Abstract

A resist releasing agent, characterized in that it is an aqueous alkaline solution comprising a heterocyclic compound having, in its molecule, a structure represented by the following formula (1): (1) . The resist releasing agent can be used for releasing a resist from a copper plate while preventing the re-precipitation of tin on a copper plate which may be caused by a copper ion being dissolved into a resist releasing agent.

Description

Description Resist stripping agent Technical field

The present invention relates to a resist stripping agent, and more particularly to a resist stripping agent for forming a sprinkling film on copper using a resist formed in a predetermined pattern as a mask, and thereafter stripping the resist from the copper. Background art

For example, in the PWB (Printed Wiring Board) manufacturing process using the panel pattern secondary copper solder stripping method, the resist stripping after the formation of the solder-coated film is performed using sodium hydroxide, hydroxylating steel, etc. An aqueous solution of the metal hydroxide is used. As such a resist stripping agent composed of an aqueous solution, a resist stripping agent containing 1,10 phenanthroline or the like to prevent dissolution of the solder-coated film and precipitation of lead is disclosed. (Hei 6-2505041). In addition, by including predetermined water-soluble amines, ammonium hydroxides, benzotriazoles, and the like, the resist stripping time is shortened, thereby enabling high-density and high-definition pattern formation. A resist stripper (Japanese Patent Application Laid-Open No. 2001-52001) and the like have been developed.

However, the recent shift from lead-free coatings to solder-coated coatings has been progressing under the influence of lead-free coatings. Along with this, in the resist stripping process using the conventional resist stripping agent used in the panel pattern secondary copper solder stripping method, the sprinkled film eluted into the aqueous alkali metal hydroxide solution, and further, the eluted tin Is reprecipitated on metallic copper. The tin film reprecipitated on the metallic copper in this manner acts as an etching resist in the copper etching step after the resist is stripped, making uniform etching difficult and causing circuit formation defects and the like. Disclosure of the invention

Therefore, an object of the present invention is to provide a resist stripping agent that can strip a resist without causing tin re-deposition on copper after forming a sprinkling film on copper. is there.

In order to achieve such an object, the resist stripping agent of the present invention is configured to be an alkaline aqueous solution containing at least a heterocyclic compound having a structure represented by the following formula (1) in the molecule.

N ヽ

C—SH formula (1)

Further, the resist stripping agent of the present invention has a configuration in which the heterocyclic compound is 2-benzimidazolethiol, and the 2-cyclic imidazolethiol is contained in a range of 10 to 50,000 ppm. did.

Further, in the resist stripping agent of the present invention, the heterocyclic compound is 2-mercapto-11-methylimidazole, and the 2-mercapto-11-methylimidazole is used in an amount of from 20 to 50,000 ppm. It was configured to be contained.

The resist stripping agent of the present invention is configured such that the heterocyclic compound is 2-thioperacil, and the 2-thioperacil is contained in the range of 500 to 50,000 ppm.

Further, the resist stripping agent of the present invention is configured such that the heterocyclic compound is 2,4-dithiopyrimidine, and the 2,4-dithiopyrimidine is contained in the range of 200 to 50,000 ppm. .

In the resist stripping agent of the present invention, the heterocyclic compound is 2-mercapto-14-methylpyrimidine hydrochloride, and the 2-mercapto-14-methylpyrimidine hydrochloride is contained in the range of 2,000 to 50,000 ppm. Configuration.

According to the present invention, when the resist stripping agent is an alkaline aqueous solution containing at least a heterocyclic compound having a predetermined structure in the molecule, the heterocyclic compound is adsorbed on the copper surface to form an insoluble film. This coating forms the copper in the resist stripper. Since dissolution (oxidation) is suppressed, resist stripping is possible while preventing re-deposition of tin (reduction of ^{Sn 2+} ). BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described.

The resist stripping agent of the present invention is an alkaline aqueous solution containing at least a complex ring compound having a structure represented by the following formula (1) in the molecule.

N.

C—SH type (1)

N In such a resist stripper of the present invention, the heterocyclic compound is adsorbed on the copper surface to form an insoluble film, and this film suppresses the dissolution (oxidation) of copper in the resist stripper. For this reason, the resist can be stripped while preventing re-deposition of tin (reduction of ^{Sn 2+} ).

As the heterocyclic compound having the structure represented by the above formula (1) in the molecule, specifically, 2-benzimidazolethiol represented by the following structural formula (A); 2-mercapto-11-methylimidazole represented by the following structural formula (C), 2-thioperacyl represented by the following structural formula (D), 2,4-dithiopyrimidine represented by the following structural formula (D), and 2 represented by the following structural formula (E) —Mercapto-14-methylpyrimidine hydrochloride and the like.

SH structural formula (A)

H

SH structural formula (B)

CH- Structural formula (c)

Structural formula (D)

HCI structural formula (E)

The content of the heterocyclic compound having the structure represented by the above formula (1) in the molecule in the resist stripping agent depends on the type of the heterocyclic compound to be used and the amount of copper eluted into the resist stripping agent (for example, 30 To about 50 ppm) or the like. For example, when the above-mentioned 2-benzimidazolethiol is contained as a heterocyclic compound, it is 10 ppm or more, when the above-mentioned 2-mercapto-11-methylimidazole is contained, it is 20 ppm or more, and the above 2-thioperacil is used. , 500 ppm or more when containing 2,4-dithiopyrimidine, and 200 ppm or more when containing 2,4-dithiopyrimidine, and 2,000 when containing 2-mercapto-14-methylpyrimidine hydrochloride. The content can be not less than p pm. If the amount of the heterocyclic compound contained in the resist stripping agent is insufficient, the effects of the present invention will not be sufficiently exhibited. On the other hand, the upper limit of the content of the heterocyclic compound in the resist stripping agent is not particularly limited. If it exceeds 000 ppm, no further effect can be obtained, and a negative effect such as a decrease in the resist peeling rate and discoloration of the substrate copper foil occurs. Therefore, the content is preferably 50,000 ppm or less.

The pH of the resist stripping agent of the present invention can be 11 to 14, preferably 12.8 to 13.4. Sodium hydroxide, alkali metal hydrosulfide oxides such as potassium hydroxide, also _c can monoethanolamine § Min, diethanol § Min, triethanolamine § Min, dissolving a water-soluble Amin such Echirenjiamin obtain the desired p H If necessary, an antifoaming agent comprising a polyether nonionic surfactant can be added to the resist stripping agent of the present invention as other additives. The content of such an additive is preferably 1 gZL or less.

When the resist is stripped using the resist stripping agent of the present invention, the temperature of the resist stripping agent is not particularly limited, but is preferably set, for example, in the range of 40 to 50 ° C. The contact between the resist stripping agent and the resist may be any of an immersion method, an injection method, and the like.

Next, the present invention will be described in more detail with reference to examples.

[Example 1]

(Preparation of test piece)

A pattern was formed on a double-sided resin-coated copper foil (copper thickness 18 im, glass epoxy substrate) using a dry film resist (PHOTEC HN240, manufactured by Hitachi Chemical Co., Ltd.). Thereafter, a spun film having a thickness of 5 mm was formed on the copper foil, and then cut into a size of 5 cm × 5 cm to prepare a test piece.

(Preparation of resist stripping agent)

As a heterocyclic compound having a structure represented by the above formula (1) in the molecule, 2-benzimidazole thiol, 2-mercapto-1-methylimidazole, 2-thiodilacil represented by the above structural formulas (A) to (E) , 2,4-dithiopyrimidine and 2-mercapto-14-methylpyrimidine hydrochloride were added to a 3% aqueous sodium hydroxide solution (200 mL, liquid temperature 45 ° C) at 2000 ppm to give 5 types of Resist strippers (samples 1 to 5) were prepared. Also, a trace amount of copper-ammine complex aqueous solution was added to these resist stripping agents (samples 1 to 5) and copper ions were added at the concentrations shown in Table 1 below. Was contained.

Further, a resist stripping agent (comparative sample 1) consisting only of a 3% aqueous sodium hydroxide solution (liquid volume 200 mL, liquid temperature 45 ° C) was prepared. Examples of the heterocyclic compound include benzotriazole represented by the following structural formula (I), 2-benzothiazole thiol represented by the following structural formula (II), and 2-mercaptoone represented by the following structural formula (III) 5-Methyl-1,3,4-thiadiazol, 2,5—dimercapto-1 represented by the following structural formula (IV) 1,2,3,4-Thiadiazole, 2—thiazoline mono represented by the following structural formula (V) Two kinds of resists were added by adding 2000 ppm of 2-thiol and 2-imidazolinethione represented by the following structural formula (VI) to a 3% aqueous solution of sodium hydroxide (liquid volume 200 mL, liquid temperature 45 ° C). Release agents (comparative samples 2 to 7) were prepared.

Structural formula (I)

SH structural formula (Π)

Structural formula (

m)

Structural formula (

IV)

SH

Structural formula (V) Structural formula (VI)

A trace amount of an aqueous solution of copper-ammine complex was added to these resist strippers (Comparative Samples 1 to 7) to contain copper ions at the concentrations shown in Table 1 below.

(Resist stripping and copper foil etching)

The test piece was immersed in each resist stripping agent (samples 1 to 5 and comparative samples 1 to 7) for 5 minutes to strip the resist.

After that, spray with ammoniacal alkaline etchant (copper concentration = 138 _g , chlorine concentration = 160 gZL, ammonia concentration = 8.7 N, pH = 8.4) at a liquid temperature of 50 ° C with a spray pressure of 1.5. The copper foil of the test piece was subjected to an etching treatment by spraying at a kg / cm ^{2 for} about 30 seconds.

(Evaluation)

The test specimen after the etching treatment was visually observed and evaluated according to the following criteria. The results are shown in Table 1 below.

(Evaluation criteria)

：: Copper foil is removed uniformly without any residual copper

: Non-uniform removal of copper foil, localized residual copper due to substitutional precipitation of tin table 1

Resist copper; [ppm]

Containing heterocyclic compound

剝脑 0 1 o 2 0 5 0 1 0 0 2 0 0 3 0 0

2 -Benzimidazole thiol 〇〇〇〇〇〇〇 2 2 2 -Mercapto-1-methylimidazosole 〇〇〇〇 X X X

2-ゥシシ〇〇〇〇〇〇

2, 4 -dithiopyrimidine 〇〇〇〇〇〇 ϊ ϊ ϊ ϊ 斗斗 ^ ϊ 5 2-mercapto-4 -methylpyrimidine ^ salt 〇〇〇〇〇〇〇〇

J ± f Fiber Doo 1 〇 X X X X X X t $ Kodo 2 Benzotriazole 〇 X X X X X X Female 2-Benzothiazonoretite 〇〇 X X X X X

2-Mercapto-5-methyl ilH, 3,4-thiadiazole 〇〇 X X X X X 5 2, 5-Dimercapto-1,3,4-thiadiazole 〇〇 X X X X X

Jtl Brain 6 2-Thiazoline-2-thiol 〇〇〇 XXXX i $ Doo 7 2 -Imidazolinethione 〇〇〇〇 XXX

As shown in Table 1, the resist stripping agent of the present invention (samples 1 to 5) containing the heterocyclic compound having the structure represented by the above formula (1) in the molecule contains copper ions in the resist stripping agent. It was possible to remove the resist without causing the tin to re-deposit on the copper even when copper ions were present, as well as when not present. However, in sample 2 (containing 2-mercapto-11-methylimidazole as a heterocyclic compound), tin was reprecipitated on copper at a copper concentration of 200 ppm or more. However, since the concentration of copper dissolved in the resist stripping agent in the PWB manufacturing process is generally about 30 to 50 ppm, it is judged that the resist stripping agent of Sample 2 is at a sufficiently practical level.

On the other hand, a resist stripping agent containing no heterocyclic compound having the structure represented by the above formula (1) in the molecule (Comparative Samples 1 to 7) is used only when copper ions are not present in the resist stripping agent. The resist could be stripped off without causing re-precipitation of tin on copper. However, when copper ions were present in the resist stripping agent, tin was reprecipitated on copper, which was not practical.

[Example 2]

(Preparation of test piece)

A test piece was produced in the same manner as in Example 1.

(Preparation of resist stripping agent)

As a heterocyclic compound having a structure represented by the above formula (1) in the molecule, 2-benzimidazolthiol, 2-mercapto-111-methylimidazol represented by the above structural formulas (A) to (E), 2-thioperacil, 2,4-dithiopyrimidine, and 2-mercapto-14-methylpyrimidine hydrochloride were added at 3% each to the concentrations shown in Table 2 below (8 levels from 10 to 2000 ppm). It was added to aqueous sodium hydroxide solution (liquid volume 20 OmL, liquid temperature 45 ° C) to prepare 40 kinds of resist strippers. Further, by adding a trace amount of an aqueous solution of copper-ammine complex to these resist stripping agents, copper ions were contained at 50 ppm.

(Resist stripping and copper foil etching)

In the same manner as in Example 1, the test piece was stripped of the resist, and then the copper foil was etched. (Evaluation)

The test piece after the etching treatment was evaluated according to the same criteria as in Example 1, and the results are shown in Table 2 below.

Table 2

Of heterocyclic compounds! ^ [ppm]

F) Heterocyclic compounds contained in the resist

10 20 50 100 200 500 1000 2000

2-benzimidazole thiol 〇〇〇〇〇〇〇〇

2-mercapto-1-methylimidazole X 〇〇〇〇〇〇 O

2-Chorasil X X X X X 〇〇〇

2,4-dithiopyrimidine X X X X 〇〇〇〇

2-mercapto-4-methylpyrimidine salt XXXXXXX 〇

As shown in Table 2, each resist stripping agent of the present invention containing a heterocyclic compound having the structure represented by the above formula (1) in the molecule has a complex structure according to the type of the heterocyclic compound contained. There is an appropriate lower limit for the content of the ring compound, and at a content higher than the lower limit of the content, it was possible to remove the resist without causing re-precipitation of tin on copper.

[Example 3]

(Preparation of test piece)

A test piece was produced in the same manner as in Example 1.

(Preparation of resist stripping agent)

As a heterocyclic compound having the structure represented by the above formula (1) in the molecule, 2,4-dithiopyrimidine represented by the above formula (D) was prepared. Also, an aqueous solution of 3 <½monoethanolamine + 0.5% tetramethylammonium hydroxide (solution volume 2 O Om, liquid temperature 45 ° C) was prepared. The 2,4-dithiopyrimidine described above was added to this aqueous solution at 2000 ppm to prepare a resist stripper (sample 6). In addition, a trace amount of an aqueous solution of copper-ammine complex was added to this resist stripper to contain copper ions at the concentrations shown in Table 3 below.

In addition, a resist stripper (comparative sample 8) consisting only of 3% monoethanolamine + 0.5% tetramethylammonium hydroxide aqueous solution (liquid volume 200 mL, liquid temperature 45 ° C) was prepared. . In addition, as the heterocyclic compound, benzotriazole represented by the structural formula (I) and 2-benzothiazole thiol represented by the structural formula (II) in Example 1 were each added with 3% monoethanolamine + 0.5% Two kinds of resist stripping agents (Comparative Samples 9, 10) were prepared by adding 2000 ppm to tetramethylammonium hydroxide aqueous solution (liquid volume 200 mL, liquid temperature 45 ° C). A trace amount of an aqueous solution of copper-ammine complex was added to these resist stripping agents (comparative samples 8 to 10) to contain copper ions at the concentrations shown in Table 3 below.

(Resist stripping and copper foil etching)

The test piece was stripped of the resist in the same manner as in Example 1, and then the copper foil was etched.

(Evaluation) The test piece after the etching treatment was evaluated according to the same criteria as in Example 1, and the results are shown in Table 3 below.

As shown in Table 3, the resist stripping agent (sample 6) of the present invention containing 2,4-dithiopyrimidine having the structure represented by the above formula (1) in the molecule was prepared by adding copper in the resist stripping agent. It was possible to remove the resist without causing the tin to re-deposit on the copper even when copper ions were present, as well as when no copper was present.

On the other hand, the resist stripping agent containing no heterocyclic compound having the structure represented by the formula (1) in the molecule (Comparative Samples 8 to 10) contains copper ion in the resist stripping agent. Only when not, it was possible to strip the resist without re-precipitation of tin on copper. However, when copper ions were present in the resist stripping agent, tin was reprecipitated on copper, which was not practical.

[Example 4]

(Preparation of test piece)

A test piece was produced in the same manner as in Example 1.

(Preparation of resist stripping agent)

As a heterocyclic compound having the structure represented by the above formula (1) in the molecule, 2,4-dithiopyrimidine represented by the above formula (D) is used in a concentration (10 to 20%) shown in Table 4 below. 3% monoethanolamine + 0.5% aqueous solution of tetramethylammonium hydroxide (liquid volume: 200 mL, liquid temperature: 45 ° C) To prepare eight types of resist strippers. Further, by adding a trace amount of an aqueous solution of copper-ammine complex to these resist stripping agents, copper ion was contained at 50 ppm.

(Resist stripping and copper foil etching)

In the same manner as in Example 1, the test piece was stripped of the resist, and then the copper foil was etched.

(Evaluation)

The test pieces after the etching treatment were evaluated according to the same criteria as in Example 1, and the results are shown in Table 4 below.

Table 4

Concentration of 2, 4-dithiopyrimidine [ppm]

Heterocyclic compound contained in resist stripping agent

10 20 50 100 200 500 1000 2000

2, 4-dithiopyrimidine XXXX 〇〇〇〇

As shown in Table 4, the resist stripping agent of the present invention containing 2,4-dithiopyrimidine having the structure represented by the above formula (1) in the molecule has a 2,4-dithiopyrimidine content of Above 200 ppm, the resist could be stripped off without re-precipitation of tin on copper. Industrial applicability

As described above, the resist stripping agent according to the present invention is capable of causing tin to re-precipitate on copper after forming a spontaneous film using a resist formed in a predetermined pattern as a mask on copper. It is suitable for stripping resist from copper, and can be used, for example, in a PWB (Printed Wiring Board) manufacturing process using a panel pattern secondary copper solder stripping method.

Claims

The scope of the claims

1. A resist stripping agent, which is an aqueous solution containing at least a heterocyclic compound having a structure represented by the following formula (1) in the molecule.

C—SH type (1)

2. The resist stripping agent according to claim 1, wherein the heterocyclic compound is 2-benzimidazole thiol, and the 2-benzimidazole thiol is contained in the range of 10 to 50,000 ppm.

3. The resist stripping agent according to claim 1, wherein the heterocyclic compound is 2-mercapto-11-methylimidazole, and contains the 2-mercapto-11-methylimidazole in the range of 20 to 50,000 ppm.

4. The resist stripping agent according to claim 1, wherein the heterocyclic compound is 2-thioperacil, and the 2-thioperacil is contained in the range of 500 to 50,000 ppm.

5. The resist stripping agent according to claim 1, wherein the heterocyclic compound is 2,4-dithiopyrimidine, and the 2,4-dithiopyrimidine is contained in a range of 200 to 5,000 ppm. .

6. The resist stripping agent according to claim 1, wherein the heterocyclic compound is 2-mercapto-14-methylpyrimidine hydrochloride, and the 2-mercapto-14-methylpyrimidine hydrochloride is in a range of 2,000 to 50,000 ppm. Contained within.