JP3315749B2 - Stripping method and stripping solution for water-soluble resist - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stripping a water-soluble resist and a stripping solution in a wiring board manufacturing process.

[0002]

2. Description of the Related Art As one method of manufacturing a wiring board, there is known a method of forming wiring by using solder as an etching resist. Taking a general case of this method as an example, a substrate having copper foil laminated on both sides is subjected to copper plating after drilling, and thereafter, portions other than the portion to be plated are covered with an organic resist film. This is subjected to solder plating, and after removing the organic resist film, unnecessary portions of copper are removed by etching. There is a method in which a water-soluble resist is used for the organic resist film and the organic resist film is peeled off with an alkaline aqueous solution. The stripping solution used for stripping the water-soluble resist is generally a strong alkaline aqueous solution such as sodium hydroxide or potassium hydroxide, and is often used at pH 13 or higher. At this time, the temperature is 40 to 50 ° C., and the time required for peeling is
It is generally about two to three minutes.

[0003] The actual stripping time is almost the same as the stripping time of the resist (about 40 to 40) because the water-soluble resist is completely stripped without leaving any stripping residue or the like in the high-density pattern portion.
(50 seconds). For this reason, during much of the stripping operation, copper (the stripped portion of the water-soluble resist) and the solder plating are simultaneously exposed to the stripping solution.

[0004] Since the stripping solution is a strongly alkaline solution as described above, the solder, which should serve as an etching resist, is dissolved and its thickness becomes insufficient.
Further, one of the constituent metals (tin) of the solder may be excessively dissolved. In particular, in the peripheral portion of the substrate or in a sparse pattern, the current density of the solder plating becomes large, the tin component in the solder plating increases, and it tends to be easily dissolved. For this reason, in the subsequent alkaline etching step, it cannot fulfill the role of a sufficient etching resist, and a defect such as disconnection or chipping may occur in the wiring. Further, when the water-soluble resist is peeled off, the local battery action due to the contact between the copper and the solder is also a factor promoting the corrosion and melting of the solder described above. Therefore, in order to prevent this corrosion and dissolution, a method of adding a reducing substance, further, a sodium arylsulfonate or an organic sulfur compound, a method of adding a borohydride compound, a method of adding an imidazole compound, Dimethylpyrazole is disclosed in JP-A-63-183445.
JP-A-64-24254, JP-A-64-24254
No. 81295 and JP-A-62-151589, respectively. Further, in the stripping of the water-soluble resist, lead ions may precipitate on the copper surface after the stripping of the water-soluble resist and hinder etching, thereby causing a short circuit between wirings. In order to prevent the precipitation of lead, a method of adding an oxidizing agent is disclosed in JP-A-63-38.
No. 588.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 63-18 / 1988
3445, JP-A-64-24254, JP-A-64-81295, and JP-A-62-1515.
In the method disclosed in JP-A-89-89, if the peeling operation is performed by a spray method, a sufficient effect cannot be obtained. Also,
JP-A-63-38588 discloses a method using an oxidizing agent as a method for preventing the precipitation of lead, and JP-A-63-183445 and JP-A-64-81295 disclose the dissolution of solder. It is incompatible with the method using a reducing substance shown as a method for performing the method. That is, until now, it has been difficult to simultaneously suppress the dissolution of solder and prevent the precipitation of lead.

[0006] The present invention is excellent in dissolution inhibiting the I, at the same time, water-soluble resist separation method which is excellent in preventing precipitation of lead
And a stripper .

[0007]

According to the present invention, a plating resist is formed with a water-soluble resist on a substrate on which a copper foil is laminated.
In a water-soluble resist stripping method for performing solder plating and then stripping the water-soluble resist, an organic substance represented by the formula (1), N-tris (hydroxymethyl) methylglycine (also known as tricine) is contained in a stripping solution. Or
It is characterized by containing an organic substance represented by the formula (2) or a salt thereof.

[0008]

Embedded image (To bind N in the above formula directly to the -CH ₂ COOH group
R and R ′ are a substituent or a molecule
Squeeze the chains. )

[0009]

Embedded image (The N in the formula - CH ₂ PO (OH) is a ₂ group and a tertiary amine to directly bond, R, R 'represents a substituent group or a molecular chain.)

Further, at least one of aminoguanidine, hydrazines, sulfurous acid, dithionous acid or a salt thereof, borohydride, carbazate, thiourea dioxide, sulfinic acids, sulfoxy acids, hydrazides and semicarbazide salts. It is characterized by including.

Japanese Patent Application Laid-Open No. 63-38588 describes the effect of residual solder plating solution components on the precipitation of lead that inhibits wiring formation. However, according to the study results of the authors, it is considered that the precipitation of lead is caused in the stripping solution. Hereinafter, this will be described in detail. Tin and lead, which are constituent metals of the solder used for the copper etching resist, can be dissolved at a pH of 13 or more, as shown in FIG. 17-11 in “Introduction to Corrosion and Corrosion Prevention of Metals” p. Potential-pH diagram ", and
FIG. 17-12, “Potential-pH diagram” of p243
And so on. Actually, when a high-density solder plating pattern having a wiring width and a space width of about 100 to 150 μm is formed on the copper surface, and a drop of about 40 g / l sodium hydroxide aqueous solution containing 400 ppm of lead ions is dropped, The authors have found that after standing at room temperature for several minutes, the exposed copper is easily observed to turn gray. In addition, when the gray part is analyzed, lead is detected. The reason for this is that the dissolution of the metal component of the solder plating and the re-deposition of the lead ion occur simultaneously or sequentially in the droplet. The details of this mechanism are unknown. Such a phenomenon seems to occur because there are three kinds of metals, that is, lead and tin of the solder plating metal and copper (the portion where the solder plating is not performed). Thus, the dissolution of the solder and the re-precipitation of lead in the alkaline stripping solution are easily confirmed.

Japanese Unexamined Patent Publication (Kokai) No. 63-6387 discloses a method for suppressing the melting of solder.
-183445, JP-A-64-81295, JP-A-62-151589 and JP-A-63-151589.
JP-A-38588 discloses examples of the dissolution rate and the amount of dissolution upon standing at room temperature as Examples and Comparative Examples. As shown in the examples of each of these four publications, dissolution can be suppressed to some extent,
It turns out that dissolution cannot be completely suppressed. In actual work, generally, at a spray pressure of 1 to ² kg / cm ² , a stripper at a temperature of 40 to 50 ° C. is brought into contact with a substrate being conveyed using a conveyor to remove a water-soluble resist. A spray method for peeling is often used. Like this
When a fresh liquid is constantly supplied to the substrate surface, the apparent diffusion coefficient becomes incomparably larger than that at the time of standing, and the dissolution rate of the solder may be much higher than the value of the example of the above publication. Estimated easily. Therefore, even if the above-described dissolution suppressing method is employed, the solder dissolves in the stripping solution together with the number of processed substrates, and the amount of metal ions increases. Actually, using a spray-type water-soluble resist stripper, the OPC parsoli (trade name, manufactured by Okuno Pharmaceutical Co., Ltd.), which is a chemical containing a reducing agent, corresponding to the method disclosed in JP-A-63-183445. was added to the liquid, the substrate of 200 meters ² (solder area: 25%)
After peeling off the dry film HF450 (trade name, manufactured by Hitachi Chemical Co., Ltd.), the concentration of lead ions in the liquid was 300 to 400 ppm.
The present inventors have found that when the amount of lead ions in the stripping solution is about 400 ppm, the deposition of lead on the substrate surface starts to be visually observed, and the remaining alkali etching causes residual copper.

Therefore, as a result of intensive studies, it was found that when lead ions increase in the solution, the dissolution is accelerated. Further, JP-A-63-183445, JP-A-64-2425.
No. 4, JP-A-64-81295 and JP-A-62-151589 were tested by a method for measuring a dissolution current value described later. As a result, lead ions were present in the solution. Then, the dissolution increased, and it was found that a sufficient inhibitory effect could not be obtained. The reason why the dissolution is accelerated in the presence of lead ions is that the lead reprecipitation reaction described above
It is presumed that it was a counter electrode reaction of corrosion and dissolution.
When the dissolution current was measured, it was found that the lead ion in the solution was 5%.
In the case of 0 to 100 ppm, precipitation of lead cannot always be confirmed visually, but it was found that such a dissolution acceleration phenomenon occurred. That is, in general peeling work, it is considered that the dissolution of the solder is particularly problematic due to such an acceleration phenomenon in addition to a simple dissolution phenomenon in which the solder dissolves in an alkaline solution. Therefore, as a result of studying a method of forming a complex with lead ions and suppressing the precipitation of lead, an organic substance represented by the formula (1), tricine, or a compound represented by the formula (2) is contained in an alkaline stripping solution. It turned out that it is effective to add an organic substance or these salts.

[0014]

Embedded image (To bind N in the above formula directly to the -CH ₂ COOH group
R and R ′ are a substituent or a molecule
Squeeze the chains. )

[0015]

Embedded image (The N in the formula - CH ₂ PO (OH) is a ₂ group and a tertiary amine to directly bond, R, R 'represents a substituent group or a molecular chain.)

As a result of adding the above compound to the stripping solution, the change in the ratio of lead to tin in the solder plating before and after the stripping of the water-soluble resist hardly changes, and the wiring portion is etched (chipped) by alkali etching thereafter. And disconnection defects) can be prevented.

Specific examples of the compound of the formula (1) or (2) include dihydroxyethylglycine, 1,2-cyclohexanediaminetetraacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, Examples include hydroxyethylethylenediaminetriacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), and salts thereof. In general, the effective range of the amount added differs depending on the ratio of lead of the complex formed with lead ions and the molecular weight of the organic substance. However, practically, the addition range of 0.05 g / l or more is effective. In addition, adding an unnecessarily large amount is disadvantageous in terms of cost.
l is a practical maximum addition amount. When a plurality of the organic substances are used, the content of the present patent is defined by replacing the term "addition amount" with "total addition amount". Practically, the more preferable range of the addition amount is 0.1 to 50 g / l.
It is. Furthermore, aminoguanidine, hydrazines, sulfurous acid, dithionous acid or salts thereof, borohydride,
A further effect can be obtained by adding at least one of carbazate, thiourea dioxide, sulfinic acids, sulfoxy acids, hydrazides, and semicarbazide salts. Examples of aminoguanidines include aminoguanidine bicarbonate, aminoguanidine sulfate, aminoguanidine hydrochloride, and the like. Examples of the hydrazines include hydrazine hydrate, monomethylhydrazine, dimethylhydrazine, and the like, and examples of the salts thereof include hydrazine sulfate, hydrazine carbonate, and hydrazine hydrochloride. Examples of the sulfite include sodium sulfite and potassium sulfite. Examples of dithionite include sodium hydrosulfite, potassium hydrosulfite, and ammonium hydrosulfite.
Examples of the borohydride include dimethylamine borane, sodium borohydride, and potassium borohydride. Examples of the carbazate include methyl carbazate (alias: methyl carbazate) and ethyl carbazate (alias: ethyl carbazate). Examples of the sulfinic acids include formamidine sulfinic acid, and examples of the sulfoxy acids include sodium formaldehyde sulfoxylate (also called sodium hydroxymethanesulfonate) commonly called Rongalit. Examples of the hydrazides include carbohydrazide, acetohydrazide and isonicotinic acid hydrazide. Examples of the semicarbazide salt include semicarbazide sulfate and semicarbazide hydrochloride. Note that thiourea dioxide is decomposed in an alkaline solution to form formamidine sulfinic acid, and thus has the same effect as formamidine sulfinic acid. Each of the above compounds shown as the second additive shows a reducing effect in the stripping solution, and the amount of addition varies depending on the reducing equivalent and the life (duration of the reducing effect) of these compounds. However, from a practical viewpoint such as solubility and cost, a desirable addition amount is 0.01 to
100 g / l. When a plurality of second additives are used, the content of the present patent is defined by replacing the term “addition amount” with “total addition amount”. Practically, a more desirable range of the addition amount is 0.05 to 50 g / l. In general, disodium hydrogen phosphite and sodium phosphinate (also known as sodium hypophosphite), which are known as reducing agents, do not show sufficient reducing properties in the stripping solution, and also have a dissolution inhibiting effect. (Measurement of dissolution current) was not obtained. It is considered that the reason for this is that, under the pH condition of the stripping solution, the reduction life is extremely short, not more than several minutes. As for sodium thiosulfate, the reduction life was obtained to some extent, but the dissolution suppressing effect was not obtained.
This may be because sodium thiosulfate has a low reducing ability and is insufficient for suppressing dissolution. Also, aldehydes such as formaldehyde, terephthalaldehyde acid, o-phthalaldehyde acid, and benzaldehyde-
o Sulfonic acid, terephthalaldehyde, and benzaldehyde 2,4 disulfonic acid have extremely short life as a reducing agent in a stripping solution, and the amount of the reducing agent (measured by redox titration with iodine) is initially charged in 30 minutes or less. The value was 1/10 or less of the value calculated from the amount, which was not practical. Phenols such as gallic acid, ethyl gallate, n-propyl gallate, methyl gallate, pyrogallol, p
Sodium hydroxybenzenesulfonate and 2,4 xylenol had a short reduction life and were not practical. Aminoguanidine has a reducing effect in the stripping solution, but guanidines having no amino group, such as 1,1,3,3 tetramethylguanidine and guanidine sulfate, have no effect and are not suitable. . As described above, reducing substances that are effective when added to the stripping solution are:
As shown in this patent, it was only very limited. Further, the reducing agent added to the stripping solution comes into contact with the substrate during the stripping operation. Upon examination with sodium sulfite, contact with copper promoted decomposition. In the case of the present invention, such a reduction in the life of the reducing agent was suppressed by the addition of the organic substance represented by the above formula (1) or (2) or a salt thereof.

[0018]

The conventional method for suppressing the dissolution of the solder in the stripping solution has been effective under the stationary condition. However, under conditions where the new liquid is always in contact, such as a spray, the dissolution of the solder is larger than expected, and as a result, lead ions in the stripping liquid increase as the substrate is processed.
The present invention has been achieved by obtaining the finding that the effect of the conventional dissolution suppressing method is inhibited even in the presence of 100 ppm of lead ions.

According to the present invention, by adding a specific substance capable of forming a complex with a metal ion to a stripping solution, a lead ion is blocked or a copper surface is blocked to obtain an effect of suppressing dissolution of solder plating. Conceivable. Further, in order to obtain a further dissolution suppressing effect, a specific reducing agent was added. In the method of adding only a known reducing agent, a sufficient effect could not be obtained due to the action of lead ions dissolved from the solder plating. However, in the case of the present invention, a substance capable of forming a complex with a metal ion prevents the precipitation of lead ions, and as a result, it was possible to obtain a dissolution suppressing effect by adding a reducing agent. Here, the following is presumed as one of the reasons why the dissolution of the solder is suppressed by the reducing agent. A reaction in which metal (lead, tin) in the solder dissolves in ions such as zinc acid, lead acid, stannic acid, and stannic acid is an oxygen demanding reaction. The reducing agent added to the stripping solution reduces dissolved oxygen in the solution and reduces the concentration of dissolved oxygen in the solution. For this reason, the melting reaction of the solder is suppressed.

In practice, the dissolved oxygen concentration was measured with several reducing agents. As a result, in the case of sodium hydrosulfite, sodium sulfite, formamidinesulfinic acid and hydrazine, the dissolved oxygen concentration was decreased at room temperature. From the measurement of the dissolution current value, the effect was small at room temperature, but the dissolved oxygen concentration was measured at 50 ° C. for sodium aldehyde sulfoxylate, aminoguanidine sulfate, sodium borohydride, etc. The decrease was not so large at room temperature, and a large decrease was observed at 50 ° C. Thus, there was a correlation between the reduction of the dissolved oxygen concentration due to the addition of the reducing agent and the effect of suppressing the dissolution of the solder. Further, the heavy metal has an action of accelerating the decomposition of the reducing agent, but in the case of the present invention, the decomposition of the reducing agent is suppressed probably because the heavy metal is blocked. As is apparent from the above, the present invention has solved the problems of lead precipitation and dissolution at the same time.

[0021]

Examples (Examples and Comparative Examples of Dissolution Inhibiting Additives) A NaOH aqueous solution of 40 g / l and a lead concentration of 150 mg / l.
(150 ppm), and the mixture was stirred for about 2 hours to completely dissolve the lead sulfate and prepare a liquid. 50 ml of this solution was poured into a beaker having a capacity of 100 ml, and copper and a solder plate coated so that each had an exposed area of 4 cm ² were immersed in the solution to form an electrode for measuring current flowing in the solution. Copper and solder electrodes were connected between the lead wires from the electrodes via a 10 ohm resistor. The dissolution current can be measured by measuring the voltage between both ends of the resistor. The measurement was performed at about 20 ° C. while stirring the liquid with a magnetic stirrer. Further, 0.2 g of an additive shown in Table 1 below was added to 2 to 3 ml of an aqueous NaOH solution 4.
A solution dissolved in 0 g / l was prepared. These liquids were poured into a stirring beaker, and the change in the dissolution current was measured.

[0022]

[Table 1] Table 1 shows the results. When the current value after the addition of the additive (additive concentration: about 4 g / l) was lower than the current value before the addition by more than 20%, Δ was determined when the current value was less than 20% or conversely increased. In most cases, the current value was not reduced. In particular, Comparative Example 20
About 23 contained sulfur compounds, nitro compounds of Comparative Examples 32-35, and sodium bromate of Comparative Example 54,
Even the addition of these compounds to a sodium hydroxide solution without lead ions resulted in a significant increase in the dissolution current, rather promoting the dissolution of the solder.

(Examples and Comparative Examples of Second Additive) Next, the effect of suppressing the dissolution of the second additive (reducing agent) was examined. The effect was confirmed by measuring the melting current while maintaining the liquid temperature of 50 ° C. and using a solder and a copper electrode while stirring the liquid with a magnetic stirrer. More specifically, a 10 ml NaOH aqueous solution 40 g /
1 g of the reducing agent was heated to 50 ° C., and this solution was added to 40 ml of DT also heated to 50 ° C.
The reaction was performed by adding 40 g / l of an aqueous NaOH solution containing 4 g / l of PA. The evaluation was evaluated as ○ when the current value decreased by 20% or more due to the addition of the second additive shown in Table 2, and as x when the addition was not performed. The results are shown in all examples after the additive was added (additive concentration: about 4 g /
The current value of 1) was reduced by 20% or more compared to the current value before being turned on, and in all of the comparative examples, the current value did not decrease in most of the comparative examples.

[0024]

[Table 2]

(Effect of Extending Life of Reducing Agent by First Additive) The effect of extending the life of the reducing agent by the first additive was examined. N
In an aOH aqueous solution (NaOH concentration: 40 g / l), sodium sulfite was added as a second additive at a reducing agent concentration of 0.1%.
It was adjusted to be 3N (19 g / l). In this solution, a solution (Table 3-1 and Examples 24-28) added so that the concentration of the first additive was 4 g / l and a solution not added (Table 3-2 and Comparative Example 66) were used. I made it. Also, separately
O 2 in an aqueous NaOH solution (NaOH concentration: 40 g / l)
The PC solution was added, and the solution was adjusted to 0.3 N (25 ml / l in the amount of the OPC solution, Comparative Example 67). In a 300 ml tall beaker, add these 10
0 ml and a 2 cm square copper-clad laminate were added, and the temperature was kept at 50 ° C. with a water bath. 2.5 minutes per minute with air pump
~ 3 liters of air were injected to bring the liquid and air into contact.
At this time, in order to improve the contact between the air and the liquid, fine bubbles were formed using a glass ball filter (Kinoshita type, type 2, diameter 20 mm). This liquid is sampled appropriately,
The reducing agent concentration was measured by titration with iodine, and the change with time was examined. The evaluation was evaluated as Δ when the time required for the reducing agent concentration to reach 50% of the initial value was 6 hours or more, and x when the time was 6 hours or less. Actually, Examples 24 to 2 shown in the table were used.
In the case of No. 8, the reducing agent concentration was maintained at 80% or more after the lapse of 8 hours (converted to the concentration by evaporation of water). On the other hand, Comparative Example 68 containing no first additive
In the case of the above, the concentration was 50% or less after 1 hour, and was 10% or less after 8 hours. In Comparative Example 67, the concentration was 10% or less after 2 hours, and the concentration was reduced to about 1% after 8 hours.

[0026]

[Table 3]

(Effect of Preventing Precipitation of Lead) A copper-clad laminate was exposed and developed using a water-soluble dry film HF450 (trade name, manufactured by Hitachi Chemical Co., Ltd.) to form a pattern. This was subjected to electric solder plating to a thickness of about 5 μm. This substrate is 2cm ×
It cut out so that it might be 5 cm. At this time, half of the substrate (2 cm × 2.5 cm) was covered with a dry film, and the rest was plated with solder.
This was converted to N containing 400 ppm of lead ions and additives.
It was immersed in an aOH aqueous solution to peel off the dry film.
The peeling was performed in a beaker at a temperature of 50 ° C. with a magnetic stirrer for about 2 minutes while stirring. The precipitation of lead at this time was visually observed. In the exposed copper, those in which a gray discolored portion was observed were evaluated as x, and those in which no discoloration was observed and which had copper luster were evaluated as Δ. Table 4 shows the results.

[0028]

[Table 4]

(Change in composition of solder plating) Dry film HF450 (manufactured by Hitachi Chemical Co., Ltd.
(Trade name) using a solder-plated board (wiring width 16
0 μm / space pattern 250 μm parallel pattern) is 1 cm
X 2.5 cm cut. This was suspended in each of the liquids shown in Table 5, stirred with a magnetic stirrer, and the dry film was peeled off. The composition of the solder at this time was examined by SFT8000 (trade name, manufactured by Seiko Instruments Inc.), which is an analyzer using fluorescent X-rays.
The dry film was peeled in less than 1 minute, but in order to make the change in the composition of the solder clearer, after being left in the liquid used for peeling the dry film for 15 minutes with stirring,
The measurement was performed after washing with water. Table 5 shows the results. Incidentally, when the tin ratio of the untreated tin was measured, the maximum value was 70.7%, the minimum value was 66.8%, the average value was 68.3%, and the standard deviation was 1.04%.
Met. In the substrate treated with a liquid containing 400 ppm of lead ions, in all of the comparative examples, the dry film was peeled off, and lead was observed on the exposed copper surface. Was not seen.

[0030]

[Table 5]

(Effects of Additives in Stripper Having Lead Ions) A test was conducted to clarify the effects of the first and second additives and the synergistic effects thereof. First, Na
An aqueous solution having an OH concentration of 40 g / l was prepared. Separately, Na
Dissolve lead sulfate in an aqueous solution having an OH concentration of 40 g / l,
A liquid containing 5000 ppm of lead ions was made. Also, 0.2 g of each of the first additive (DTPA and ethylenediamine 4 (methylene phosphonic acid)) and the second additive (sodium sulfite) was added to a small amount (2 to 3 ml) of a NaOH solution (NaOH concentration: 40 g). / l). 100ml capacity
50 ml of an aqueous solution of NaOH having a concentration of 40 g / l
Using the copper and the solder electrodes described above, changes in the dissolution current when additives and the like were sequentially added were measured. The measurement was performed at 50 ° C. while stirring the liquid with a magnetic stirrer. The results are shown in FIGS. In this figure, initially, the dissolution current in an aqueous NaOH solution is measured, and the current value is gradually decreasing probably because the surface state of the electrode changes little by little (section 1). It is considered that such a phenomenon occurs even when the water-soluble resist is actually stripped. However, the time required for actual peeling (2 to 2)
(3 minutes). Here, in order to see the effect of the second additive, the previously prepared sodium sulfite is added to the liquid. Then, the current value rapidly decreases (section 2). To add an explanation, here, the second additive was added later to see the effect of the additive, but in the actual case, the electrode was added to the liquid because it was added to the liquid from the beginning. Thus, the current value has decreased from the time when the current value starts to be measured. Next, in order to check the effect of lead ions, 1 ml of the previously prepared liquid containing 5000 ppm lead is added. Then, the lead ion concentration of the added liquid becomes about 100 ppm. The addition of the lead ion completely eliminates the effect of the second additive, and sharply increases the dissolution current value (section 3). Therefore,
When the first additive DTPA (FIG. 1) and ethylenediaminetetra (methylenephosphonic acid) (FIG. 2) dissolved in an aqueous solution of sodium hydroxide are added, the increase in the current value due to lead ions is almost canceled out. It decreases to near the current value before the addition of lead ions (section 4). Thus, the current additive suppression effect is negated when lead ions are present only with the second additive, but by adding the first additive, the action of the lead ions is eliminated, and the second additive is used. The effect of the agent can be exhibited.

[0032]

According to the present invention, when the water-soluble resist is stripped with an alkaline stripping solution, the dissolution of solder plating can be suppressed and the precipitation of lead can be suppressed. Therefore, a favorable wiring without a wiring defect can be formed. As another effect, an inexpensive inorganic alkali such as sodium hydroxide or potassium hydroxide can be used for the stripping solution used in the present method in order to obtain a strong alkali. Further, since the precipitation of lead is eliminated, the area of the substrate that can be treated with the same amount of the stripping solution increases. Therefore, the amount of stripper used per unit area of the substrate is reduced, and the amount of waste liquid is reduced. This lowers the cost of processing,
Since no organic alkali is used, waste liquid treatment is also easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between an additive and a dissolution current for explaining an effect of the present invention.

FIG. 2 is a diagram showing a relationship between an additive and a dissolution current for explaining the effect of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-183445 (JP, A) JP-A-64-24254 (JP, A) JP-B-46-43123 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) G03F 7/42 C23F 1/00 H05K 3/06 H05K 3/24

Claims (10)

(57) [Claims] 1. A method for removing a water-soluble resist, comprising forming a plating resist with a water-soluble resist on a substrate on which a copper foil is laminated, performing solder plating, and stripping the water-soluble resist with a strong alkaline aqueous solution. And Jihid
Roxyethylglycine, hydroxyethyliminodivinegar
Acid, diethylenetriaminepentaacetic acid, hydroxyethyl
Tylenediamine triacetic acid, triethylenetetramine hexaacetic acid
A method for stripping a water-soluble resist, comprising 0.05 to 100 g / l of any one of the above or a salt thereof. 2. A method for removing a water-soluble resist, comprising forming a plating resist with a water-soluble resist on a substrate on which a copper foil is laminated, performing solder plating, and stripping the water-soluble resist with a strong alkaline aqueous solution. And N-tris (hydroxymethyl) methylglycine or a salt thereof in an amount of 0.05 to 100 g / l. 3. A method for removing a water-soluble resist, comprising forming a plating resist on a substrate on which a copper foil is laminated with a water-soluble resist, performing solder plating, and stripping the water-soluble resist with a strong alkaline aqueous solution. And an organic substance represented by the formula (2) or a salt thereof in an amount of 0.05 to 1
A method for stripping a water-soluble resist, comprising 00 g / l. Embedded image (N in the above chemical formula is a tertiary amine directly bonded to a —CH ₂ PO (OH) ₂ group, and R and R ′ represent a substituent or a molecular chain.) 4. The organic substance or a salt thereof contained in the stripping solution is any of ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) or a salt thereof. A method for removing a water-soluble resist. 5. A second additive comprising : aminognidine;
At least one of hydrazine, sulfurous acid, dithionite or a salt thereof, borohydride, carbazate, thiourea dioxide, sulfinic acid, sulfoxyacid, hydrazide, semicarbazide is 0.01 to 1
The method for stripping a water-soluble resist according to any one of claims 1 to 4, wherein the water-soluble resist is contained in an amount of 00 g / l. 6. strong and alkaline aqueous solution, dihydroxy et
Tilglycine, hydroxyethyliminodiacetic acid, diethyl
Lentriamine pentaacetic acid, hydroxyethyl ethylene dia
A stripping solution containing any one of mintriacetic acid and triethylenetetramine hexaacetic acid or a salt thereof. 7. A stripper comprising a strongly alkaline aqueous solution and N-tris (hydroxymethyl) methylglycine or a salt thereof. 8. A stripper comprising a strongly alkaline aqueous solution and an organic substance represented by the formula (2) or a salt thereof. Embedded image (N in the above chemical formula is a tertiary amine directly bonded to a —CH ₂ PO (OH) ₂ group, and R and R ′ represent a substituent or a molecular chain.) 9. The stripper according to claim 8, wherein the organic substance or a salt thereof contained in the stripper is any of ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) or a salt thereof. 10. As the second additive, aminoguanidine, hydrazine, sulfurous acid, dithionous acid or a salt thereof, borohydride, carbazate, thiourea dioxide, sulfinic acid, sulfoxy acid, hydrazide, semicarbazide 7. The composition according to claim 6, which comprises at least one salt.
10. The stripping solution for a water-soluble resist according to any one of items 9 to 9.