TW201731356A - Etching method of laminated body and method of manufacturing printed wiring substrate using the same can remove the metal residue between wiring at an inexpensive and simple steps in the semi-additive process of a two-layer flexible substrate - Google Patents

Abstract

The present invention provides a method for manufacturing substrate. The method resolves the above issue of using a semi-additive method in the manufacture of two-layer flexible wiring boards. In the etching of a constituent comprising a substrate metal layer and a copper, the substrate metal layer is selectively dissolved without dissolving the copper, suppressing reduction of the wiring width of the copper wiring so as to provide the manufacturing method of substrate having high reliability without defects of broken and short circuits. The etching method of the laminated body is characterized in that at least one side of the insulating substrate is formed, without adhesive, with a substrate metal layer containing more than one metal alloys selected from nickel and chromium, and a laminated body of copper coating layer is formed on a surface of the substrate metal layer. After processing the exposed substrate metal layer after performing etching removal of the copper coating layer in an aqueous solution of a water-soluble organic solvent or the organic solvent having an amino group, the etching removal is carried out by using acidic oxidizing agents containing permanganates.

Description

Method for etching laminated body and method for manufacturing printed wiring substrate using same

The present invention relates to a method of manufacturing a laminated body, and further relates to a method of manufacturing a printed wiring board which is a raw material of an electronic component such as a TAB tape or a COF tape by using the etching method.

More specifically, in the formation of a copper wiring using a semi-additive method in the method of manufacturing a printed wiring board, by performing a predetermined etching, it is possible to remove the wiring between the wiring layers without side etching in an inexpensive and simple procedure. A method of manufacturing a printed wiring board having a pattern having sufficient insulation reliability and a printed wiring board obtained by the manufacturing method can be formed even if it is a fine wiring processed product.

In general, a substrate to be used for the production of a flexible wiring board is generally divided into a three-layer flexible substrate in which a copper foil as a conductor layer is bonded to an insulating film using an adhesive (for example, see Patent Document 1). And a two-layer flexible substrate directly formed on the copper film layer as a conductor layer by a dry plating method or a wet plating method without using a binder on the insulator film.

In recent years, in order to increase the density of electronic devices, and to obtain a wiring board having a narrow wiring pitch, in this case, copper wiring by a subtractive method is used in the production of the above-described three-layer flexible substrate. In this method, a copper clad layer formed on an insulator film as a substrate is etched by a ferric chloride solution or a copper chloride solution containing hydrochloric acid in accordance with a desired wiring pattern, and a wiring portion is formed to fabricate a wiring board. In the case of manufacturing by the etching of the wiring portion, the side surface of the wiring portion is etched, that is, the side surface etching, and the cross-sectional shape of the wiring portion is likely to become a trapezoidal shape in which the bottom portion is expanded.

Therefore, in order to satisfy this requirement, in place of the conventional laminated copper foil (three-layer flexible substrate), a two-layer flexible substrate having a small copper thickness is now in the mainstream.

In order to produce a two-layer flexible substrate, as a method of forming a copper coating layer having a uniform thickness on an insulator film, a copper plating method is generally employed. Further, in order to perform copper plating, a thin film metal layer is generally formed on an insulating film to which an electroplated copper film is applied, and electrical conductivity is provided to the entire surface, and copper plating treatment is performed thereon (for example, see Patent Document 2). Further, in order to obtain a thin film metal layer on the insulating film, a dry plating method such as a vacuum deposition method or an ion plating method is generally used.

In the process of doing so, the adhesion between the insulator film and the copper coating layer is extremely weak due to the formation of a fragile layer such as CuO or Cu ₂ O on the interface thereof, and in order to maintain the adhesion strength to the copper layer required for the printed wiring board, An underlying metal layer such as a Ni-Cr alloy is provided between the insulator film and the copper coating layer (see Patent Document 3).

In the recent flexible substrate, in order to reduce the narrow pitch of the wiring with higher density of the wiring pattern, a copper wiring using a semi-additive method is used for the production of the high-density wiring substrate. In the semi-additive method, a pattern resist is formed by photolithography on a copper coating layer formed on an insulator film, and copper plating is further performed, and finally the resist is removed, and an unnecessary copper coating layer is removed by etching to form copper. Wiring (hereinafter, such etching is referred to as flash etching).

In such flashing, for example, an aqueous solution of sulfuric acid/hydrogen peroxide or the like is used as an etching liquid. In order to maintain the adhesion strength in the semi-additive method, as the underlying metal layer between the insulator film and the copper coating layer, the Ni-Cr alloy layer is widely used. Layer plating substrate. In this case, since the Ni-Cr alloy layer is hardly dissolved in the sulfuric acid/hydrogen peroxide aqueous solution, only the copper coating layer is removed by etching after the flash etching step, and the underlying metal layer remains almost completely after dissolution. Although there is a prior art relating to the removal step of the underlying metal layer and the etching liquid (see Patent Documents 4 and 5), since the base metal layer is made of nickel, it is difficult to remove the Ni-Cr alloy layer having high corrosion resistance.

As a method of removing the Ni-Cr alloy layer, for example, Patent Document 6 has two types of alkaline etching liquids such as a commercially available nickel/chromium selective etching solution containing hydrochloric acid and sulfuric acid and a potassium permanganate solution. Description of the etching residue of the dissolved Ni-Cr alloy.

Further, in the case of treatment with a commercially available acidic etching solution containing hydrochloric acid and sulfuric acid, it is difficult to completely remove Cr, and it is necessary to use it in combination with an alkaline etching solution such as a potassium permanganate solution suitable for removal of Cr. The treatment with an alkaline etching solution such as a permanganic acid solution is effective for removing Cr, but in order to use the etching liquid, an alkaline-dedicated processing apparatus is necessary, and it is difficult to easily increase the steps. Further, since it is a strong alkali solution, there is a high possibility that the dissolved Cr becomes a form of toxic hexavalent chromium, and therefore treatment of the waste liquid requires sufficient attention and cost.

Further, since the acidic etching solution contains about 10 to 20% by weight of hydrochloric acid, copper is dissolved in such a state, and therefore it is necessary to contain a certain amount of an inhibitor to suppress copper dissolution, so the daily copper dissolution concentration and inhibitor concentration Management is necessary.

As a Ni-Cr selective etching solution in the subtractive method, the inventors have proposed a method in which an acidic permanganic acid solution can be used in an inexpensive and simple manner, and the side surface of the copper wiring is less etched to remove the Ni-Cr alloy. A method of etching residue (refer to Patent Document 7). However, the technique disclosed in Patent Document 7 is a technique for removing the etching residue of the Ni-Cr alloy by etching of copper in the subtractive method, and is not to be in flash erosion or the like. It is difficult to remove the Ni-Cr alloy remaining by etching.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 6-132628

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-139448

[Patent Document 3] Japanese Patent Laid-Open No. Hei 6-120630

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2003-258411

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-294797

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2007-201216

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2010-13688

However, unlike the Ni-Cr alloy which removes the residual residue of the underlying metal layer as the subtractive method, in the case of the semi-additive method, it is necessary to remove the underlying metal layer which is hardly etched after the flash etching. Even in the case of using an acidic permanganic acid solution which is effective for selective removal of such a Ni-Cr alloy, the removal of the underlying metal layer after flashing must take a corresponding period of time, due to the long etching time. The risk of side etching of copper wiring. Further, it is easy to cause dissolution of the underlying metal component between wirings, and it is difficult to manufacture a substrate having high reliability.

In view of such circumstances, the present invention provides a solution to the above problem of using a semi-additive method in the manufacture of a two-layer flexible wiring board in which etching is not selectively dissolved in the etching of the constituent body including the underlying metal layer and copper. A highly reliable substrate that dissolves the underlying metal layer, suppresses reduction in wiring width of the copper wiring, and has no defects such as disconnection or short circuit Production method.

In order to solve such a problem, the inventors of the present invention have studied an etching method for forming a fine wiring by a semi-additive method for a two-layer flexible substrate provided with a base metal layer, and as a result, it has been found that in order to remove the base metal The layer is subjected to a step of treating an acidic oxidizing agent containing permanganate having an effect of dissolving the underlying metal layer component while suppressing dissolution of copper, and a solvent containing a hydrophilic solvent before the treatment with the oxidizing agent. The pretreatment liquid is pretreated, and the effect of removing the underlying metal layer component between the fine wirings quickly and without dissolution remains, and the present invention has been completed.

In the first aspect of the invention, the method for etching a laminated body is characterized in that the insulating substrate is formed of an alloy containing one or more metals selected from the group consisting of nickel and chromium, at least one surface of the insulating substrate is not transmitted through the adhesive. a method for etching a base metal layer and a laminate having a copper coating layer formed on a surface of the base metal layer, and a base metal layer exposed after etching and removing the copper coating layer, by a water-soluble organic solvent having an amine group After the aqueous solution of the organic solvent is treated, it is etched and removed by using an acidic oxidizing agent containing permanganate.

According to a second aspect of the present invention, in the etching method of the laminated body, the step of removing the manganese compound by the manganese residue removing liquid is further applied after the step of treating the acidic oxidizing agent according to the first aspect of the invention.

According to a third aspect of the invention, the oxidizing agent according to the first or second aspect of the invention is the solution containing 0.01 to 10% by weight of permanganate and 0.005 to 2% by weight of hydrochloric acid.

A fourth invention of the present invention is a method of etching a laminate, which is characterized The organic solvent of the first to third inventions is an alkanolamine.

According to a fifth aspect of the invention, there is provided a method of producing a printed wiring board, wherein the base metal formed of an alloy containing one or more metals selected from the group consisting of nickel and chromium is not transmitted through at least one surface of the insulating substrate. The layer and the surface of the layered body in which the copper film layer is formed on the surface of the underlying metal layer, and the method of manufacturing the printed wiring board formed by the semi-additive method, the copper film layer is removed by etching The removal of the underlying metal layer is carried out by a water-soluble organic solvent having an amine group or an aqueous solution of the organic solvent, followed by etching and removal using an acidic oxidizing agent containing permanganate.

According to a sixth aspect of the invention, in the method of producing a printed wiring board, after the step of treating the acidic oxidizing agent according to the fifth aspect of the invention, the step of removing the manganese compound by the manganese residue removing liquid is further applied.

According to a seventh aspect of the invention, in the method of producing a printed wiring board, the acidic oxidizing agent according to the fifth or sixth aspect of the invention contains a solution of 0.01 to 10% by weight of permanganate and 0.005 to 2% by weight of hydrochloric acid.

According to a ninth aspect of the invention, the organic solvent of the fifth to seventh inventions is an alkanolamine.

According to a ninth aspect of the present invention, in a method of manufacturing a printed wiring board, the insulating substrate according to the fifth aspect of the invention is a polyimide film, a polyamide film, a polyester film, or a polytetrafluoroethylene system. At least one or more resin films selected from the group consisting of a film, a polyphenylene sulfide film, a polyethylene naphthalate film, and a liquid crystal polymer film.

According to the method of manufacturing a printed wiring board of the present invention, it is possible to use an inexpensive etching method using the etching method of the present invention in a semi-additive method of a two-layer flexible substrate. In a simple procedure, the metal residue between the wirings is removed by etching on the side of the copper-free layer, and fine wiring having high insulation reliability can be obtained, so that the industrial effect is extremely large.

1‧‧‧Insulator film

2‧‧‧Base metal layer

3‧‧‧copper coating

4‧‧‧resist pattern

5‧‧‧ wiring pattern

6‧‧‧Resist pattern removal area

1 is a cross-sectional view showing a series of manufacturing steps of a flexible wiring board, wherein (a) is a two-layer flexible substrate, (b) a resist pattern forming step, and (c) a wiring pattern forming step; d) a resist removal step, (e) a flashing step, and (f) a base metal layer removing step.

The present invention is an etching method for a laminate, characterized in that the underlying metal layer formed of an alloy containing one or more metals selected from nickel and chromium is formed on at least one side of the insulating substrate without transmitting a binder, and An etching method of a laminate of a copper coating layer formed on a surface of the underlying metal layer, for removing a base metal layer exposed after etching the copper coating layer, using a water-soluble organic solvent having an amine group or the organic solvent After the aqueous solution has been treated, it is removed by etching through an acidic oxidant containing permanganate.

The etching method of the laminated body of the present invention will be described by taking the following as an example: the insulating substrate is, for example, a copper film layer of a flexible substrate in which a base metal layer and a copper film layer are formed, using a polyimide film. The surface is etched to form a pattern resist by photolithography, further electroplating copper is performed, and finally, the resist is peeled off, and after removing the unnecessary copper film layer by flash etching, an underlying metal layer which is not required between the formed wirings is performed. The step of treating with an acidic etching solution containing permanganate, and pretreatment with a pretreatment liquid selected from an organic solvent having an amine group or an aqueous solution of the organic solvent before the treatment with an oxidizing agent.

As the two-layer flexible substrate, the base metal layer is provided to ensure the practical adhesion strength between the insulator film and the copper film layer.

However, it is considered that after etching the formed pattern, the metal component of the extremely small amount of the underlying metal layer directly bonded to the insulator film remains in the gap portion between the lead and the lead even after the etching or the subsequent cleaning step. The surface layer portion of the insulator film.

When the inventors of the present invention performed the HHBT (High Temperature High Humidity Bias Test), it was estimated that the metal component remaining in the surface layer is one of the causes of migration.

(1) 2 layers of flexible substrate a. Insulator film

In the present invention, when an insulating film is used for the insulating substrate, a two-layer flexible substrate can be formed.

The insulating film to be used is preferably a polyimide film, a polyamide film, a polyester film, a polytetrafluoroethylene film, a polyphenylene sulfide film, or a polymer, from the viewpoint of heat resistance. At least one or more thermosetting resin films selected from the group consisting of a naphthalate film and a liquid crystal polymer film. Among them, a polyimide film and a polyamide film are particularly preferable films for use in applications requiring high-temperature bonding in reflow soldering or the like.

Further, a film having a thickness of the insulator film of 8 to 75 μm can be suitably used. In order to reduce the coefficient of thermal expansion or the like, an inorganic material such as glass fiber or CNT may be appropriately added to the resin film.

b. base metal layer

The material of the underlying metal layer formed on the insulating substrate (insulating film) is an alloy containing one or more selected from the group consisting of nickel and chromium. As the base metal layer, an alloy in which at least one metal selected from Mo, Ta, Ti, V, Co, and W is further added may be used.

Further, the base metal layer preferably contains 7% by mass or more and 25% by mass or less of chromium, and more preferably contains 15% by mass or more and 25% by mass or less of chromium. The alloy of the underlying metal layer is preferred because it has high corrosion resistance, high adhesion, and heat resistance.

Further, an oxide of a metal of the underlying metal layer may be laminated on the underlying metal layer. The composition of the underlying metal layer can be appropriately selected in consideration of the insulation reliability in the HHBT test of the two-layer flexible substrate and the printed wiring board or the adhesion to the insulating substrate.

The thickness of the underlying metal layer of the printed wiring board of the present invention is preferably from 3 to 50 nm.

When the underlying metal layer is thinner than 3 nm, problems such as infiltration of an etching solution during wiring processing and a decrease in wiring peeling strength such as floating of a wiring portion occur, which is not preferable. Further, when the film thickness is thicker than 50 nm, etching becomes difficult, which is not preferable.

c. Copper coating

The copper coating layer was formed into a film by using a sputtering apparatus in which a copper target was placed in a cathode for sputtering. At this time, it is preferred that the base metal layer and the copper coating layer are continuously formed in the same vacuum chamber. After the underlying metal layer is formed, the film is taken out to the atmosphere, and when a copper coating layer is formed using another sputtering apparatus, it is necessary to sufficiently perform dehydration before film formation.

Further, the layer thickness of the copper coating layer is usually more preferably in the range of 10 nm to 500 nm. When the thickness of the copper coating layer is 10 nm or more, the surface of the substrate is generated by pinholes. The defects are repairable. When the film resist is thinner than 10 nm, the pattern resist is formed, and it is not preferable because the power supply becomes difficult when the copper plating process is further performed. On the other hand, if the efficiency of the removal step by flash erosion is considered, the thickness of the copper coating layer may be 500 nm or less.

(2) Formation of wiring patterns

Next, the formation of the wiring pattern will be described with reference to Fig. 1 .

1 is a series of cross-sectional views showing a manufacturing step of a flexible wiring board of the present invention, wherein (a) is a two-layer flexible substrate, (b) a resist pattern forming step, and (c) a wiring pattern forming step. And (d) is a resist removal step, (e) is a flashing step, and (f) is a base metal layer removing step.

In Fig. 1, a 1-series insulator film, a 2-series base metal layer, a 3-series copper film layer, a 4-series resist pattern, a 5-series wiring pattern, and a 6-type resist pattern removal region are shown.

First, a resist pattern 4 is formed on the copper film layer 3 by photolithography (Fig. 1(b)). After the resist pattern 4 is formed, a region where the resist is not formed in the resist pattern 4 (that is, a region where the copper film layer 3 is exposed) is formed by the electrolytic copper plating method (FIG. 1(c) ).

This wiring pattern 5 is composed of an electrolytic copper plating layer.

After the wiring pattern 5 is formed, the resist pattern 4 is removed. In the region 6 where the resist pattern 4 is removed, the copper coating layer 3 is exposed and appears (Fig. 1 (d)). Next, the copper coating layer 3 exposed in the region 6 is removed by flashing. The composition of the etching liquid when removing by flash etching is preferably a sulfuric acid concentration of 5 to 50 g/L and a hydrogen peroxide concentration of 10 to 60 g/L.

The underlying metal layer 2 is exposed in the region 6 from which the copper clad layer 3 has been removed by flashing (Fig. 1(e)).

Thereafter, the obtained two flexible substrates are impregnated into (A) an aqueous solution of an amine group-containing water-soluble organic solvent or the aforementioned organic solvent, followed by treatment with (B) a permanganate-containing acidic oxidizing agent liquid to remove The base metal layer 2 exposed in the region 6 (Fig. 1(f)).

Here, the two layers of the flexible substrate are impregnated into (A) a water-soluble organic solvent having an amine group or an aqueous solution of the organic solvent in order to improve the exposed base metal layer to the permanganate-containing acidic oxidant liquid. Wettability.

In the (A) treatment, it is known that the underlying metal layer contains one or more alloys selected from nickel and chromium, and the alloy constituting the underlying metal layer is passive. That is, the treatment is as follows: on the surface of the exposed base metal layer, even if a passivation state is formed in the removal step of the copper coating layer, the impregnation to the permanganate-containing acid is improved by impregnation into a water-soluble organic solvent having an amine group. Wettability of the oxidant solution.

The (A) treated water-soluble organic solvent having an amine group is preferably an alkanolamine. Examples of the water-soluble alkanolamine aqueous solution include monoethanolamine, diethanolamine, and triisopropanolamine. Further, an ethylene oxide or/and a propylene oxide adduct of ethylenediamine or diethylenetriamine may be mentioned.

The concentration of the water-soluble alkanolamine is not particularly limited. However, when the liquid is sprayed by a spray method, it is preferably from 1 to 30% by weight from the viewpoint of the balance of the viscosity. If the viscosity is high, it is necessary to wash it thoroughly. When the temperature of the solvent is at least room temperature, the removability can be exhibited. However, from the viewpoint of shortening the treatment time, it is preferably in the vicinity of 40 ° C to 55 ° C.

Further, the time of immersion in a water-soluble organic solvent having an amine group or an aqueous solution of the organic solvent is preferably 1 second or longer, more preferably 10 seconds or longer. However, even if it is extended to be impregnated into a water-soluble organic solvent having an amine group or an aqueous solution of the organic solvent The time does not affect the removal of the base metal layer.

From the viewpoint of productivity, the time of immersion in a water-soluble organic solvent having an amine group or an aqueous solution of the organic solvent is even within 1 minute, more preferably within 30 seconds.

The permanganate-containing acidic oxidizing agent is preferably a solution containing 0.01 to 10% by weight of permanganate and 0.005 to 2% by weight of hydrochloric acid.

If the permanganate concentration is a low concentration, the etching time becomes slow, and even if the high concentration effect does not change, it is more preferable that the permanganate concentration is 0.1 to 5% by weight. Further, when the concentration of hydrochloric acid is high, the copper wiring is easily dissolved, and if the concentration is low, the etching rate is slow and the etching time is increased. Therefore, the concentration of hydrochloric acid is preferably 0.01 to 0.5% by weight.

(B) The treatment method of the permanganate-containing acidic oxidizing agent may be either a spraying method or a dipping method. The treatment temperature of the acidic etching solution is preferably from 20 ° C to 60 ° C. However, if the temperature is low, the removal of the passivation layer is likely to be insufficient, and the etching time is prolonged. Further, if the temperature is high, the occurrence of hydrochloric acid fumes increases, and the amount of dissolved copper increases, so that it is more preferably 30 ° C to 50 ° C.

The treatment time of the permanganate etching solution containing hydrochloric acid is preferably from 20 seconds to 3 minutes.

If the time is shorter than 20 seconds, it is insufficient for removing the residual residue of the underlying metal layer; if it is longer than 3 minutes, the amount of copper dissolved increases.

Further, after the treatment with the permanganate-containing acidic oxidizing agent, depending on the conditions, manganese or the like adheres to the etching surface to form a metal compound such as an oxide. In order to remove it, it is preferred to use a reducing oxalic acid. An organic acid aqueous solution such as ascorbic acid or a commercially available manganese residue removal liquid used to remove the manganese residue of the alkaline permanganate etching solution is treated.

When the manganese compound is removed by the manganese residue removal liquid, and the residue due to the underlying metal layer is not completely removed between the wirings, it is preferred to treat it again with an acidic oxidizing agent containing permanganate.

As described above, according to the method for producing a printed wiring board of the present invention, it is possible to perform fine wiring processing without causing the lead thinning caused by the side etching of the copper layer.

Thus far, a manufacturing method in which a two-layer flexible substrate is processed into a printed wiring board by a semi-additive method has been described as an example. As the insulating substrate to be used, in addition to the insulator film, a ceramic plate, a glass plate, a plate containing a fiber such as glass fiber, an epoxy resin, or a plastic plate can be used.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples.

[Example 1]

A printed wiring board was produced by a semi-additive method. Indicates the order in which they are made.

A 20 wt% Cr-Ni alloy was formed into a base metal layer in a thickness of 20 to 30 nm by a sputtering method on a polyimide film (manufactured by Toray DuPont Co., Ltd., film thickness: 50 μm). Next, a copper coating layer is formed on the underlying metal layer in a range of 200 to 350 nm to form a two-layer flexible substrate, and a pattern resist is formed by photolithography on the produced two-layer flexible substrate, and further copper plating is performed. The resist is peeled off.

Thereafter, a commercially available sulfuric acid/hydrogen peroxide-based soft etching liquid (manufactured by Lingjiang Chemical Co., Ltd., trade name: CPE800) was used for flash etching to prepare a comb-tooth test substrate having a copper wiring width/wiring pitch of 15 μm/10 μm. .

In order to remove the underlying metal layer exposed between the wirings of the obtained test substrate, The pretreatment was carried out by immersing in a 5.0 wt% aqueous solution of monoethanolamine heated to 50 ° C for 10 seconds (A), and after washing with water, immersing in an aqueous solution containing 1.0 wt% of potassium permanganate and 0.3 wt% of hydrochloric acid. Second (B) processing.

The obtained test substrate was observed under an optical microscope to confirm the dissolution of the underlying metal layer between the wirings. Moreover, the presence or absence of re-etching of the copper wiring was also confirmed using an optical microscope.

Further, with respect to the test substrate thus manufactured, according to JPCA-ET04 (2007), DC 60 V was applied between the terminals in an environment of 85 ° C and 85% RH, and the electric resistance was observed for 1,000 hours. The resistance becomes a time point of 10 ⁶ Ω or less short-circuit fault is determined, if after lapse of 1000 hours or more 10 ⁶ Ω still, it is determined to be under acceptable conditions HHBT. The target HHBT endurance time of the wiring substrate was 1000 hours.

The test results are shown in Table 1.

[Embodiment 2]

The evaluation was carried out in the same manner as in Example 1 except that the concentration of the monoethanolamine aqueous solution was 25 wt%. The results are shown in Table 1.

[Example 3]

The evaluation was carried out in the same manner as in Example 1 except that the aqueous monoethanolamine solution was an aqueous solution of triisopropanolamine. The results are shown in Table 1.

(Comparative Example 1)

In the same manner as in Example 1, except that the water-soluble alkanolamine treatment was not carried out before the treatment with the permanganate-containing acidic oxidizing agent, the test substrate was produced in the same manner as in Example 1. The evaluation of the test substrate was carried out.

The results are shown in Table 1 below.

(Comparative Example 2)

In the first embodiment, in addition to the treatment of removing the exposed underlying metal layer (A) (B), a commercially available acidic etching solution CH-1920 (an etching solution containing hydrochloric acid and sulfuric acid manufactured by MEC Co., Ltd.) was used. In the same manner as in Example 1, a test substrate was produced, and the test substrate was evaluated.

The results are shown in Table 1 below.

(Comparative Example 3)

A test substrate was prepared and evaluated in the same manner as in Example 1 except that an etching liquid in which potassium permanganate was used in an amount of 1 wt% of potassium permanganate and 5 wt% of hydrochloric acid was removed.

The results are shown in Table 1 below.

(Comparative Example 4)

A test substrate was prepared and evaluated in the same manner as in Example 1 except that an etching liquid containing 0.1% by weight of potassium permanganate and 0.3% by weight of hydrochloric acid and the remaining amount of water was used as the underlying metal layer exposed after the flash etching.

The results are shown in Table 1 below.

(Reference example 1)

In the first embodiment, in order to remove the exposed underlying metal layer, a commercially available acidic etching solution CH-1920 (manufactured by MEC Co., Ltd.) was used, and further, 5 was used. A test substrate was prepared and evaluated in the same manner as in Example 1 except that the alkaline permanganic acid solution of wt% potassium permanganate and 5 wt% potassium hydroxide was treated.

The results are shown in Table 1 below.

Further, in the observation between the wirings in Table 1, an example in which no dissolution of the underlying metal layer was present was indicated as "O", and an example in which dissolution remained was indicated as "X".

Further, as a result of HHBT, an example in which there is no short circuit for 1000 hours or more is indicated as “O”, and an example in which short circuit is performed within 1000 hours is indicated as “×”.

As shown in Table 1, in Comparative Example 2 in which the base metal was removed using only the commercially available acidic etching liquid, the dissolution residue between the wirings was removed, but the HHBT was short-circuited within 1000 hours. In the case of Comparative Example 3 in which the alkaline permanganic acid treatment was further carried out after the treatment of the commercially available acidic etching solution, the target time was finally reached in the HHBT. Further, in the acidic permanganic acid treatment of Comparative Example 1, the dissolution of the underlying metal layer was observed between the wirings, and the removal of the underlying metal layer was not performed. However, in Example 1 in which acidic permanganic acid treatment was carried out using a hydrophilic solvent as a pretreatment, there was no dissolution residue between wirings, and good results were also obtained for HHBT.

(industrial availability)

As described above, according to the present invention, when a copper wiring pattern is formed by a semi-additive method, in particular, according to the etching liquid and the etching treatment step of the present invention, the conventional two-layer flexible substrate is quickly dissolved by an inexpensive and simple procedure. By using the base metal layer component remaining after the flash etching treatment by the semi-additive method, and since etching of copper can be suppressed, fine wiring having high insulation resistance can be easily obtained without side etching or damage. The effect is great.

In addition, the present invention has been described above by taking a step of forming a printed wiring board by a semi-additive method for a two-layer flexible substrate. The at least one surface of the insulating substrate is formed to contain nickel and chromium from at least one side of the insulating substrate. An etching method of a base metal layer formed of an alloy of one or more selected metals and a laminate having a copper coating layer formed on a surface of the underlying metal layer, and the copper coating layer is removed by etching to be easily removed Further, the underlying metal layer can be easily formed into a pattern of a circuit or the like by using a laminate of the underlying metal layer and the copper film layer.

1‧‧‧Insulator film

2‧‧‧Base metal layer

3‧‧‧copper coating

4‧‧‧resist pattern

5‧‧‧ wiring pattern

6‧‧‧Resist pattern removal area

Claims (9)

An etching method for a laminated body, characterized in that an underlying metal layer formed of an alloy containing one or more metals selected from nickel and chromium is formed on at least one side of an insulating substrate without a binder; An etching method for forming a laminate of a copper coating layer on the surface of the underlying metal layer, wherein the underlying metal layer exposed after etching the copper coating layer is removed by a water-soluble organic solvent having an amine group or the organic After the aqueous solution of the solvent is treated, it is etched and removed by an acidic oxidizing agent containing permanganate. The etching method of the laminate according to claim 1, wherein the step of removing the manganese compound by the manganese residue removing liquid is further increased after the treatment step using the acidic oxidizing agent. The etching method of the laminate according to claim 1 or 2, wherein the oxidizing agent contains a solution of 0.01 to 10% by weight of permanganate and 0.005 to 2% by weight of hydrochloric acid. The etching method of the laminate according to any one of claims 1 to 3, wherein the organic solvent is an alkanolamine. A method of producing a printed wiring board, characterized in that an underlying metal layer formed of an alloy containing one or more metals selected from nickel and chromium is formed on at least one side of an insulating substrate without a binder; a method for producing a printed wiring board having a pattern formed by a semi-additive method on a surface of a laminate of a copper coating layer on a surface of the base metal layer, wherein the underlying metal layer is removed by etching the copper coating layer; After being treated with a water-soluble organic solvent having an amine group or an aqueous solution of the above organic solvent, it is etched and removed by an acidic oxidizing agent containing permanganate. The method for producing a printed wiring board according to claim 5, wherein after the treatment step using the acidic oxidizing agent, the step of removing the manganese compound by the manganese residue removing liquid is further increased. The method for producing a printed wiring board according to claim 5 or 6, wherein the acidic oxidizing agent contains a solution of 0.01 to 10% by weight of permanganate and 0.005 to 2% by weight of hydrochloric acid. The method for producing a printed wiring board according to any one of claims 5 to 7, wherein the organic solvent is an alkanolamine. The method for producing a printed wiring board according to claim 5, wherein the insulating substrate is a polyimide film, a polyamide film, a polyester film, a polytetrafluoroethylene film, or a polyphenylene sulfide film. At least one or more resin films selected from the group consisting of polyethylene naphthalate film and liquid crystal polymer film.