JP2003224348A - High density printed wiring board and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a manufacturing method for easily and reliably forming a conductive layer of a conductive material such as gold plating on a partial surface of a high-density printed wiring board on which high-density wiring is formed by plating. provide. In a method of manufacturing a high-density printed wiring board,
Forming a wiring pattern on both surfaces of the insulating substrate, forming a conductive treatment conductor layer by electroless plating and electrolytic plating on the entire surface of both surfaces, and forming a resist pattern having an opening region at a predetermined position on the wiring pattern. Removing the conductive layer in the opening area, forming a sub-conductor layer of a conductive material different from the conductive layer in the opening area by electrolytic plating, using the conductive layer 4 as a plating electrode, and forming the resist pattern. Removing and exposing the exposed conductive layer under the layer of the resist pattern.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a high-density printed wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a printed wiring board having high-density wiring, it is necessary to perform gold plating on the surface of the exposed conductor pattern portion in order to protect the exposed conductor pattern portion and to avoid any inconvenience during mounting. . After forming the high-density wiring, if the lead wiring for electrolytic plating cannot be drawn out, form a layer by electroless plating, or
Alternatively, when lead wiring is possible, a method of forming lead wiring for connecting to a conductor for performing electroplating, forming a layer by electrolytic plating, and then removing the lead wiring for connecting to the conductor is generally adopted. There is. However, the gold plating layer formed by the electroless plating method has a problem in that it is unstable in terms of quality. In the case of the gold plating layer formed by the electrolytic plating method, the lead wiring to be connected to the conductor is formed for electrolytic plating. Then, there is a problem that a step of removing the lead wiring connected to the conductor is separately generated after the layer is formed by the electrolytic plating method.

Further, in the case where lead wires for gold plating are drawn out from the independent terminals to the end surface portion of the substrate of the printed wiring board, the lead wiring ends when the substrate is externally processed and separated into individual pieces. Therefore, it is also practiced to coat the end portion of the lead by applying an insulating resin to the end portion because it is exposed.

In high density printed wiring boards, there is a great demand for forming a gold plating layer on the mounting pad portion. Generally, the method of forming the gold plating layer by the electroplating method is adopted, but when the lead wiring cannot be formed due to the design specifications, the method of forming the gold plating layer by the electroless plating method is used. May be used instead.

When a method of forming a gold plating layer by electrolytic plating is adopted, after forming the lead wiring,
Since the wiring pattern in the state where the lead wiring is arranged tends to deteriorate the electrical characteristics of the circuit due to the lead wiring,
The lead wiring may be removed after the gold plating layer is formed by the electrolytic plating method.

When the gold plating layer is formed by the electroless plating method, there is a problem that the reliability after mounting is insufficient.

There is a problem that the electrolytic plating method cannot be adopted in the printed wiring board having high-density wiring in which the lead wiring for forming the electrodes cannot be arranged. When the electrolytic plating method is adopted, the formation of the lead wiring and the lead wiring are required. However, there is a problem in that the number of steps for removing is increased and the construction period is extended.

[0008]

When the gold plating layer is formed by the conventional electroless plating method, there is a problem that the reliability after mounting is insufficient. High-density printed wiring boards that require a high level of quality are insufficient in terms of long-term reliability and electrical characteristics.

Further, in the conventional method of forming a gold plating layer by electrolytic plating, it is necessary to add the steps of forming the lead wiring and removing the lead wiring, which is complicated, and some steps are added to the normal step. There must be. Therefore, there is a problem that not only the manufacturing cost increases, the construction period becomes longer, but also the yield rate decreases.

Further, since the lead wiring is formed, the space between the wirings cannot be narrowed, there is a limit to the high density wiring, and the impedance characteristic is adversely affected in terms of quality. Therefore, an extra space is formed in the wiring pattern. However, there is a problem in that it is not possible to cope with high-density wiring in which the patterns are close to each other or a wiring pattern having many high-speed circuits.

The present invention has been devised in order to solve the above-mentioned problems, and gold plating etc. can be easily and surely performed by electrolytic plating on a part of the surface of a high-density printed wiring board on which high-density wiring is formed. Another object of the present invention is to provide a manufacturing method for forming a conductor layer of the conductive material.

[0012]

According to a first aspect of the present invention, a conductor layer 2 on both surfaces of an insulating substrate 1 is subjected to a patterning treatment, and at least a part of the surface of a patterned wiring pattern 3 is the conductor layer. Sub-conductor layer 6 of a conductive material different from 2
A high density printed wiring board, characterized in that at least a part of the wiring pattern 3 is a fine and high density wiring pattern 3 having a pitch of 100 μm or less.

Next, according to a second aspect of the present invention, the conductor layers 2 on both surfaces of the insulating substrate 1 are subjected to a patterning treatment, and at least a partial opening area of the patterned wiring pattern 3 is the insulating substrate 1. The sub-conductor layer 6 is formed by electrolytic nickel plating of a conductive material having a surface area of 1% to 5% of the total area, the opening surface being different from that of the conductor layer 2, and electrolytic gold plating.
A high density printed wiring board, characterized in that at least a part of the wiring pattern 3 is a fine and high density wiring pattern 3 having a pitch of 100 μm or less.

Further, the invention according to claim 3 of the present invention comprises at least the following steps, and the method for manufacturing a high-density printed wiring board according to claim 1. (A) A step of forming the conductor layers 2 on both surfaces of the insulating substrate 1. (B) A step of patterning the conductor layer 2 to form a wiring pattern 3. (C) A step of forming a conductive-treated conductor layer 4 by subjecting the entire surface of both surfaces of the insulating substrate to electroconductivity treatment by the electroless plating method or the electroless plating method and the electroplating method including the surface of the conductor layer 2. (D) A step of forming a resist layer 5 on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern 3. (E) A step of forming a resist pattern 8 having an opening region 7 on both surfaces of the insulating substrate and at predetermined positions on the wiring pattern 3. (F) A step of conducting a conductive treatment by an electroless plating method or an electrolytic plating method, which is exposed on the entire surface of the opening area 7 formed in the resist pattern 8, and removing the conductive treatment conductor layer 4 thus formed with a dedicated etching solution. . (G) A step of forming the sub-conductor layer 6 of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening region 7 on the conductor pattern by using the conductor layer 4 for conductive treatment as a plating electrode. (H) A step of removing the resist pattern 8 with a dedicated stripping solution. (I) A step of conducting a conductive treatment by an exposed electroless plating method or an electrolytic plating method under the resist pattern layer, and removing the conductive treatment conductor layer 4 thus formed with a dedicated etching solution.

Further, the invention according to claim 4 of the present invention comprises at least the following steps, and the method for manufacturing a high-density printed wiring board according to claim 1. (A) A step of forming the conductor layers 2 on both surfaces of the insulating substrate 1. (B) A step of patterning the conductor layer 2 to form a wiring pattern 3. (C) In the step of forming a conductive-treated conductor layer 4 on the entire surface of both surfaces of the insulating substrate, including the surface of the conductor layer 2 by electroless plating or by electroless plating and electrolytic plating. A step of forming the conductive layer with a thickness of 0.1 μm to 5 μm by copper plating. (D) A step of forming a resist layer 5 on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern 3. (E) A step of forming a resist pattern 8 having an opening region 7 on both surfaces of the insulating substrate and at predetermined positions on the wiring pattern 3. (F) A step of conducting a conductive treatment by an electroless plating method or an electrolytic plating method, which is exposed on the entire surface of the opening area 7 formed in the resist pattern 8, and removing the conductive treatment conductor layer 4 thus formed with a dedicated etching solution. . (G) In the step of forming the sub-conductor layer 6 of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening region 7 on the conductor pattern by using the conductor layer 4 for conductive treatment as a plating electrode. A step of forming the sub conductor layer 6 by gold plating. (H) A step of removing the resist pattern 8 with a dedicated stripping solution. (I) A step of conducting a conductive treatment by an exposed electroless plating method or an electrolytic plating method under the resist pattern layer, and removing the conductive treatment conductor layer 4 thus formed with a dedicated etching solution.

Further, the invention according to claim 5 of the present invention is provided with at least the following steps, and the method for manufacturing a high-density printed wiring board according to claim 2 is characterized. (A) A step of forming the conductor layers 2 on both surfaces of the insulating substrate 1. (B) A step of patterning the conductor layer 2 to form a wiring pattern 3. (C) Conductivity treatment by electroless copper plating is performed on the entire surfaces of both surfaces of the insulating substrate including the surface of the conductor layer 2 to form the conductor layer 4 for conductivity treatment. With a thickness of 0.1 μm to 1.5 μm. (D) A step of forming a resist layer 5 on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern 3. (E) A step of forming a resist pattern 8 having an opening region 7 on both surfaces of the insulating substrate and at predetermined positions on the surface of the wiring pattern 3. (F) A step of performing a conductive treatment by electroless copper plating exposed on the entire surface of the opening region 7 formed in the resist pattern, and removing the conductive treatment conductor layer 4 thus formed with a dedicated etching solution. (G) In the step of forming the sub-conductor layer 6 of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening region 7 on the conductor pattern by using the conductor layer 4 for conductive treatment as a plating electrode. , In the step of forming the sub conductor layer 6 with a nickel plating layer and a gold plating layer, the thickness of the nickel plating layer is in the range of 4 μm to 5.5 μm, and the thickness of the gold plating layer is in the range of 0.5 μm to 2. Step of forming within a range of 5 μm. (H) A step of removing the resist pattern 8 with a dedicated stripping solution. (I) A step of conducting a conductive treatment by the exposed electroless copper plating under the resist pattern layer, and removing the formed conductive-treated conductor layer 4 with a dedicated etching solution.

[0017]

[Function] In a high-density printed wiring board on which high-density wiring is formed, an electrolytic plating method that does not require lead wiring when a conductive material layer is formed on a specific wiring pattern portion exposed on the surface by electrolytic plating Is to provide.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below along with embodiments.

FIG. 1 is a partial side sectional view showing an embodiment of the present invention.

A wiring pattern 3 is formed on both surfaces of an insulating substrate 1 serving as a base, and a sub conductor layer 6 is formed on a part of the surface of the wiring pattern. In the high density printed wiring board, at least a part of the wiring pattern 3 is a fine and high density wiring pattern 3 having a pitch of 100 μm or less.

Next, FIGS. 2 and 3 are side sectional views for explaining the manufacturing process of the present invention, which will be described below in detail along with the process.

As the insulating substrate 1, a printed wiring board insulating substrate having a single layer or a plurality of layers of pattern wiring is put into a process.

(A) In the step of forming the conductor layers 2 on both sides of the insulating substrate 1, a copper foil having an insulating resin layer formed on the back surface of the copper foil in advance is laid on both sides of the insulating substrate 1 and the copper foil is superposed on the surface. The layers are laminated by heating and pressing under the conditions.

(B) In the step of patterning the conductor layers 2 on both surfaces of the insulating substrate 1 to form the wiring pattern 3, after forming a resist layer using an original plate having a pattern formed in advance, the resist layer surface is formed. Then, exposure, development, and corrosion are performed, and the resist layer is peeled off to form a wiring pattern.

(C) Conductivity treatment is performed on the entire surfaces of both surfaces of the insulating substrate including the surface of the conductor layer 2 by electroless plating, or electroless plating and electrolytic plating to form a conductor layer 4 for conductivity treatment. The process will be described. In the electroless plating method, the electroconductive plating conductor layer 4 is formed on the entire surface of the double-sided insulating substrate from the surface of the insulating resin to the wiring pattern by electroless plating. Alternatively, the electroconductivity treatment by the electroplating method forms the electroconductivity-treated conductor layer 4 by using the electroconductivity-treated conductor layer 4 formed on both surfaces of the insulating substrate 1 as a plating electrode. In the case of the present invention, the thickness of the conductive-treated conductor layer 4 is 0.1 μm.
It is formed by a copper plating layer in the range of up to 5 μm. When the thickness of the conductive layer 4 is 0.1 μm to 1.5 μm, the conductive layer 4 can be formed by electroless plating, and the thickness is 1.5 μm to 5.0 μm. In case,
The electroconductive plating layer and the electrolytic plating method are used together to form the conductive treatment conductor layer 4.

(D) Both sides of the insulating substrate and the wiring pattern 3
In the step of forming the resist layer 5 on the entire surface including the surface, the resist layer 5 is pressed and heated under a predetermined condition by using a commercially available dry film having gold plating resistance, and is bonded to both surfaces of the insulating substrate. A resist layer is formed.

(E) Both sides of the insulating substrate and the wiring pattern 3
A resist pattern 8 having an opening region 7 at a predetermined position above
In the step of forming, a resist layer is formed by exposing and developing on the surface of the resist layer using an original plate on which a pattern formed in advance is formed to form a resist pattern 8 having an opening region 7.

(F) Conductive treatment of a portion exposed on the entire surface in the opening region 7 formed in the resist layer by electroless plating or electrolytic plating, and the formed conductive-treated conductor layer 4 is subjected to exclusive etching. Remove with liquid.

(G) The step of forming the sub-conductor layer 6 of a conductive material different from that of the conductor layer by electroplating in the opening region 7 on the conductor pattern by using the conductor layer 4 for conductive treatment as a plating electrode, A sub conductor layer made of nickel plating by electrolytic nickel plating is formed on the conductor pattern portion made of copper exposed in the opening region 7, and a sub conductor layer made of gold plating by electrolytic gold plating is further formed.

(H) Next, the resist layer is removed with a dedicated stripping solution.

(I) The exposed conductive layer 4 under the resist layer is removed with a dedicated etching solution.

Then, a solder resist layer is formed at predetermined positions on both surfaces of the insulating substrate to complete a high-density printed wiring board on which high-density wiring is formed.

Next, when the opening area 7 forming the above-mentioned sub-conductor layer 6 is as small as 1% to 5% of the total area of the insulating substrate 1, the thickness of the conductor of the conductive treatment conductor layer 4 is small. 0.1μ
Since electroplating is possible with the electroconductive-treated conductor layer 4 in the range of m to 1.5 μm, the electroconductive-treated conductor layer 4 is formed by using only the electroless plating method, and the electroconductivity is different from the electroconductive-plated conductor layer 2. It is possible to manufacture a printed wiring board covered with a sub-conductor layer 6 formed by electrolytic nickel plating of a conductive substance and electrolytic gold plating, reducing the burden of the step of removing the conductive treatment conductor layer 4, and improving the quality level. A high-density printed wiring board is completed.

Using the electroconductive conductor layer 4 as a plating electrode, a sub-conductor layer 6 made of a conductive material different from that of the conductor layer is formed on the entire surface in the opening region 7 of the insulating substrate by electrolytic plating. In the step of forming the sub conductor layer 6 with the nickel plating layer and the gold plating layer, the thickness of the nickel plating layer is 4
A plating layer having a thickness of μm to 5.5 μm is formed, and a gold plating layer having a thickness of 0.5 μm to 2.5 μm is formed on the entire surface of the layer. It is necessary to optimize the layer thickness of the conductive-treated conductor layer 4, the nickel-plated layer of the sub-conductor layer 6, and the gold-plated layer with reference to the degree of miniaturization of the conductor pattern, electrical characteristics, quality standards, etc. Is. In particular, since the conductive treatment conductor layer 4 is used as an electrode for electrolytic plating and then the conductive treatment conductor layer is removed, a thinner conductive treatment conductor layer can be easily removed.

[0035]

EXAMPLES Next, specific examples of the present invention will be described.

<Example 1> A high-density printed wiring board for forming a wiring pattern 3 was manufactured. An example of the step of forming the sub conductor layer 6 of a conductive material different from the conductor layer by the electroplating method will be described below.

On the entire surfaces of both surfaces of the insulating substrate, a layer which has been subjected to a conductive treatment by electroless plating is formed on the surfaces from the insulating resin layer to the conductor layer 2, and the conductive treated conductor layer is used as a plating electrode to perform an electrolytic plating method. Conductivity treatment was performed to form electroconductive-treated conductor layer 4 composed of electroless plating and electrolytic plating. The conductive layer was 2.5 μm thick and was formed by copper plating.

Next, both surfaces of the insulating substrate and the wiring pattern 3
A resist layer 5 was formed on the entire surface including the surface. The resist layer 5 was formed by using dry film having gold plating resistance.

A resist pattern 8 having an opening area 7 for mounting pads arranged at a predetermined position on the wiring pattern 3 is formed by exposing and developing the resist surface using a master plate for exposure prepared in advance. Formed.

The conductive treatment conductor layer 4 exposed on the entire surface of the opening region 7 was removed by a dedicated etching solution. The exclusive etching solution was removed by using a generally used sulfuric acid / hydrogen-based etching solution.

Next, the resist pattern 8 having the opening region 7 is used as a mask for electrolytic plating, the conductive treatment conductor layer 4 is used as a plating electrode, and a nickel layer thickness of 5 μm is formed in the opening region of the insulating substrate by electrolytic plating. , Gold layer thickness 1μ
The sub-conductor layer 6 made of m was formed.

Next, the unnecessary resist pattern 8 was removed with a dedicated stripping solution. As the stripping solution, a commonly used alkaline stripping solution was used.

All of the conductive-treated conductor layer formed by copper plating having a thickness of 2.5 μm below the resist pattern layer was removed with a dedicated etching solution. The exclusive etching solution was removed by using a generally used sulfuric acid / hydrogen-based etching solution.

[0044]

EFFECT OF THE INVENTION Using the method of the present invention, a lead wiring is not necessary, and a conductor layer made of a conductive material such as gold plating is easily and reliably formed on a partial surface of a high-density printed wiring board by electrolytic plating. It is possible to provide a manufacturing method for forming the. As an effect, electrolytic gold plating is possible even in a fine pattern in which lead wiring cannot be produced, and since there is no lead wiring, the electrical characteristics become better. Next, in the surface roughening of the copper surface on the wiring pattern and the formation of the solder resist, there is no influence on the surface of the conductor layer coated with a conductive substance such as gold plating, so that the quality deterioration can be prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view illustrating an example of a high-density printed wiring board according to the present invention.

2 (a) to 2 (e) are side sectional views for explaining a manufacturing process of the high-density printed wiring board of the present invention.

3 (f) to (i) are side sectional views for explaining the manufacturing process of the high-density printed wiring board of the present invention.

[Explanation of symbols]

1 ... Insulating substrate 2 ... Conductor layer 3 ... Wiring pattern 4 ... Conductivity-treated conductor layer 5 ... Resist 6 ... Sub conductor layer 7 ... Opening area 8 ... Resist pattern

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5E339 AB02 AD03 BC01 BC02 BD03                       BD08 BD11 BE13 CD05 CE02                 5E343 AA02 AA12 BB09 BB14 BB17                       BB23 BB24 BB44 BB61 BB71                       CC61 DD33 DD43 DD76 EE17                       ER11 ER23 ER26 GG08

Claims (5)

[Claims] 1. A printed wiring in which conductor layers on both surfaces of an insulating substrate 1 are patterned, and at least a part of the surface of a patterned wiring pattern is covered with a sub-conductor layer of a conductive material different from the conductor layer. A high-density printed wiring board, characterized in that at least a part of the wiring pattern is a fine and high-density wiring pattern having a pitch of 100 μm or less. 2. A conductive layer on both sides of an insulating substrate is subjected to a patterning treatment, and at least a partial opening area of the patterned wiring pattern is in the range of 1% to 5% of the total area of the insulating substrate. A printed wiring board, the surface of which is covered by an electrolytic nickel plating of a conductive material different from that of the conductor layer and a sub-conductor layer formed by electrolytic gold plating, wherein at least a part of the wiring pattern is fine and has a pitch of 100 μm or less. A high-density printed wiring board having a high-density wiring pattern. 3. The method for manufacturing a high-density printed wiring board according to claim 1, further comprising the following steps. (A) A step of forming conductor layers on both surfaces of the insulating substrate. (B) A step of patterning the conductor layer to form a wiring pattern. (C) A step of forming a conductive conductor layer on the entire surface of both surfaces of the insulating substrate, including the surface of the conductor layer, by a conductive treatment by an electroless plating method, or an electroless plating method and an electrolytic plating method. (D) A step of forming a resist layer on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern. (E) A step of forming a resist pattern having opening regions on both surfaces of the insulating substrate and at predetermined positions on the wiring pattern. (F) A step of conducting a conductive treatment by an electroless plating method or an electrolytic plating method, which is exposed on the entire surface in the opening region formed in the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution. (G) A step of forming a sub-conductor layer made of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening area on the conductor pattern using the conductor layer subjected to the conductive treatment as a plating electrode. (H) A step of removing the resist pattern with a dedicated stripping solution. (I) A step of conducting a conductive treatment by an exposed electroless plating method or an electrolytic plating method under the layer of the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution. 4. The method for manufacturing a high-density printed wiring board according to claim 1, which comprises at least the following steps. (A) A step of forming conductor layers on both surfaces of the insulating substrate. (B) A step of patterning the conductor layer to form a wiring pattern. (C) In the step of forming a conductive-treated conductor layer by performing electroconductivity treatment by electroless plating or electroless plating and electroplating on the entire surfaces of both surfaces of the insulating substrate, including the conductor layer surface. The thickness of the conductive layer is 0.1.
Step of forming by copper plating in the range of μm to 5 μm. (D) A step of forming a resist layer on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern. (E) A step of forming a resist pattern having opening regions on both surfaces of the insulating substrate and at predetermined positions on the wiring pattern. (F) A step of conducting a conductive treatment by an electroless plating method or an electrolytic plating method, which is exposed on the entire surface in the opening region formed in the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution. (G) In the step of forming a sub-conductor layer of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening area on the conductor pattern by using the conductor layer for electro-conductivity as a plating electrode. The process of forming the layer by gold plating. (H) A step of removing the resist pattern with a dedicated stripping solution. (I) A step of conducting a conductive treatment by an exposed electroless plating method or an electrolytic plating method under the layer of the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution. 5. The method for manufacturing a high-density printed wiring board according to claim 2, further comprising at least the following steps. (A) A step of forming conductor layers on both surfaces of the insulating substrate. (B) A step of patterning the conductor layer to form a wiring pattern. (C) The thickness of the conductive-treated conductor layer formed in the step of conducting conductive treatment by electroless copper plating on the entire surfaces of both surfaces of the insulating substrate by electroless copper plating to form the conductive-treated conductive layer. Of 0.1 μm to 1.5 μm. (D) A step of forming a resist layer on the entire surface including both surfaces of the insulating substrate and the surface of the wiring pattern. (E) A step of forming a resist pattern having an opening region on both surfaces of the insulating substrate and at predetermined positions on the surface of the wiring pattern. (F) A step of performing a conductive treatment by electroless copper plating exposed on the entire surface in the opening area formed in the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution. (G) In the step of forming a sub-conductor layer made of a conductive material different from that of the conductor layer by electrolytic plating on the entire surface of the insulating substrate and the opening area on the conductor pattern by using the conductor layer to be conductive as a plating electrode, In the step of forming the conductor layer with the nickel plating layer and the gold plating layer, the nickel plating layer has a thickness of 4 μm to 5.5 μm, and the gold plating layer has a thickness of 0.5 μm to 2.5 μm. The process of doing. (H) A step of removing the resist pattern with a dedicated stripping solution. (I) A step of conducting a conductive treatment by the exposed electroless copper plating below the layer of the resist pattern, and removing the formed conductive-treated conductor layer with a dedicated etching solution.