JPH06152105A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To provide a one-side or two-side mounted-type printed wiring board having mounting terminals of small pitch. CONSTITUTION:Mounting terminal sections 15a and conductor circuit sections 14a and a metal thin film are transferred onto the surface of an insulating substrate 17. On the other part 12'a of the transferred metal thin film than the part 12'b that surrounds the mounting terminal sections, a resist layer 18 is formed to set up the frame for a region 19. The part 12'b of the transferred metal thin film in the region 19 is removed by etching to expose the surface of the mounting terminal sections 15a. Nextly, the residual part 12'a of the transferred metal thin film gets conducted to electrocoat solder on the surface of the mounting terminal sections 15a. After that, the resist layer 18 and the residual part 12'a of the transferred metal thin film are removed in consecutive order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for manufacturing a surface mounting printed wiring board having mounting terminals with a narrow pitch.

[0002]

2. Description of the Related Art Conventionally, many methods have been applied to manufacture a surface mounting printed wiring board. As a typical example, a solder is attached to a portion of a conductor circuit where a mounting terminal is to be formed. SCL method (Solder
coat levelar method). However, in the surface mounting printed wiring board manufactured by the SCL method, regardless of whether through holes are formed or not in the surface mounting printed wiring board, the finally formed solder layer is uniform on both sides and in the same plane. It is difficult and causes variations in its thickness. When terminals of surface mount components are placed on the solder layer in such a state and sent to the reflow furnace, when the solder is melted in the furnace, the Manhattan phenomenon caused by the time difference of the solder melting occurs frequently. Become.

In order to eliminate such a trouble at the time of mounting a surface-mounted component, the variation in film thickness is small by electroplating on a portion of a conductor circuit where a mounting terminal is formed (hereinafter referred to as a mounting terminal portion). A printed wiring board having a solder layer as a mounting terminal has been proposed (see Japanese Patent Application No. 63-313841). This printed wiring board is manufactured as follows. This will be described with reference to the drawings in the case of a single-sided printed wiring board having no through holes.

First, the conductor circuit portion 2 and the mounting terminal portion 3 are formed on one surface of the insulating substrate 1 by the method described in the above publication.
Then, the metal thin film 4 is transferred to prepare a material having a flash surface (FIG. 39). After that, a resist layer 5 for solder plating is formed on the remaining surface of the surface of the metal thin film 4 excluding the portion corresponding to the mounting terminal portion 3 (FIG. 4).
0). At this time, the resist layer 5 is formed so that the edge portion 3a of the mounting terminal portion 3 and the edge portion 5a of the resist layer 5 are not displaced from each other in the width direction of the drawing.

Next, electrolytic plating is performed in the solder plating bath using the metal thin film 4 as a cathode. Since the metal thin film 4 covers the entire surface of the insulating base material 1, the solder is electrodeposited only on the metal thin film portion on the mounting terminal portion 3 to form the solder layer 6 having a small thickness variation (FIG. 41). ). At this time, the thickness of the solder layer 6 can be arbitrarily changed by appropriately selecting the electrolytic plating conditions.

After that, first, the resist layer 5 is removed by etching with an appropriate etchant, and then the metal thin film 4 located under the resist layer 5 is removed by etching with another etchant (FIGS. 42 and 43). Thus, the solder layer 6 having a small thickness variation is formed on the mounting terminal portion 3 via the metal thin film 4, and this functions as a mounting terminal.

[0007]

Since the solder layer 6 is formed by the electrolytic plating method, the above-mentioned method has the advantage that the thickness variation is small and the thickness can be adjusted to an arbitrary thickness. I have it. However, when the printed wiring board is actually manufactured by this method, the following problems occur.

That is, as shown in FIG. 40, when the solder plating resist layer 5 is formed, between the edge portion 5a and the edge portion 3a of the mounting terminal portion 3 hidden under the metal thin film 4. , It is necessary to prevent misalignment. If there is a displacement between the edge portions 3a and 5a, the solder layer 6 is not formed immediately above the mounting terminal portion 3 and one of the left and right sides in FIGS. It is formed in a state of being displaced in the direction, and deviates from the state of the regular design circuit.

In the case of a printed wiring board having a relatively wide pitch between the mounting terminals, even if the resist layer 5 and the mounting terminal portion 3 are slightly displaced from each other, there is no great disadvantage. However, when trying to form the mounting terminals with a narrow pitch, a situation occurs in which the mounting terminals adjacent to each other are short-circuited even if the positional displacement is minute.

Therefore, when the mounting terminals with a narrow pitch are formed by the above method, the resist layer 5 must be formed with extremely strict dimensional accuracy according to the narrow pitch. At present, in printed wiring boards for surface mounting, one of the goals is to improve the mounting density.
Therefore, it is required to form mounting terminals with a narrower pitch. However, in the case of the above-mentioned method, it is extremely difficult to form the resist layer 5 so that the positional deviation between the resist layer 5 and the mounting terminal portion 3 is substantially zero and to meet the above-mentioned demand.

The present invention solves the above-mentioned problems in the method described in Japanese Patent Application No. 63-313841, and enables the formation of narrow pitch mounting terminals having a pitch width of 0.5 mm or less. An object of the present invention is to provide a method for manufacturing a printed wiring board for mounting.

[0012]

In order to achieve the above-mentioned object, in the present invention, first, as a first manufacturing method, a step of forming a metal thin film on the surface of a flat conductive substrate (hereinafter , A ₁ step); after forming a pattern of the conductor circuit and the mounting terminal by covering a portion of the surface of the metal thin film where the conductor circuit portion and the mounting terminal portion are not formed with a resist mask, And a step of forming a conductor metal layer by a plating method at a place where the pattern of the mounting terminal is formed (hereinafter referred to as A ₂ step); after removing the resist mask, an insulating base material is pressure-bonded to the surface of the conductor metal layer or Step of integrating by thermocompression bonding (hereinafter,
A ₃₎ of step; by from the resulting integrated product to separate and remove only the flat conductive substrate, the conductive metal layer and a transfer to the wiring board material for the metal thin film on one surface of the insulating substrate Step (hereinafter referred to as A ₄ step); of the surface of the transfer metal thin film of the material, the surface portion except for the surface portion corresponding to the formation portion of the mounting terminal portion and the area of a desired area surrounding the surface portion is resist A step of forming a resist layer by covering with a mask (hereinafter referred to as A ₅ step); a portion of the transfer metal thin film located in a region in which the mounting terminal portion is present is removed by etching, and a conductive metal layer of the mounting terminal portion is formed. exposing the surface (hereinafter, referred to as a ₆ step); the surface of the conductive metal layer of the mounting terminal portions by electrolytic plating, electrodeposition of the conductive metal layer heterogeneous or homogeneous metal or alloy as the conductor metal do it, Forming a metal layer for instrumentation terminals (hereinafter, A of ₇ steps); and, (hereinafter referred to, A ₈ step) the resist layer and exposing sequentially removed to conductor circuits remainder of the transfer metal thin film Is provided as an essential step, and a second method of manufacturing a printed wiring board is provided, and a second method is to form a metal thin film on the surface of a flat conductive substrate (hereinafter, referred to as B ₁ step); after forming a pattern of the conductor circuit and the mounting terminal by covering a portion of the surface of the metal thin film where the conductor circuit portion and the mounting terminal portion are not formed with a resist mask, the formation point of the pattern of the mounting terminal, the step of forming a conductive metal layer by plating (hereinafter, B of ₂ steps); after removing the resist mask, the surface of the conductive metal layer A step of integrating and pressed or heated and pressed on both surfaces of Enmotozai (hereinafter, referred to as B ₃ step); by peeling removing only the flat conductive base material from the resulting integrated product, of the insulating substrate A step of transferring the conductor metal layer and the metal thin film to both sides to form a wiring board material (hereinafter referred to as a B ₄ step);
After bored a hole for a through hole in a predetermined position of the transfer metal thin film of the material, wherein the step of imparting conductivity by electroless plating on the surface of the hole for the through-hole (hereinafter, referred to as B ₅ step); the material Of the surface of the transfer metal thin film, the surface portion corresponding to the formation portion of the mounting terminal portion and the surface portion excluding the area of a desired area surrounding the mounting terminal portion and the opening portion of the through hole hole are covered with a resist mask. Te forming an etching resist layer (hereinafter, referred to as B ₆ step); the portion of the transfer metal thin film is removed by etching situated within the region where the mounting terminal portions are inherent, the surface of the conductive metal layer of the mounting terminal portions exposed to process (hereinafter, referred to as B ₇ step); and removing the etching resist layer, thereby exposing the remaining portion of the transfer metal thin film (hereinafter, referred to as B ₈ step); of the transfer metal thin film Covers the surface and edges of the remaining portion, and the step of forming a plating resist layer without covering the opening of the hole for the through-hole (hereinafter, referred to as B ₉ step); the surface of the conductive metal layer of the mounting terminal portion and the A step of forming a metal layer for mounting terminals and a plated through hole by electrodeposition of a metal or an alloy different from or the same as the conductor metal of the conductor metal layer on the surface of the hole for through hole by electrolytic plating (hereinafter , B ₁₀ process); and
A step of sequentially removing the remaining portion of the plating resist layer and the transfer metal thin film to expose a conductor circuit (hereinafter, referred to as B
₁₁ step)) is provided as an essential step, and a method for manufacturing a printed wiring board is provided.

Of these two manufacturing methods, the first manufacturing method is a method for manufacturing a single-sided mounting printed wiring board, and the second manufacturing method is a double-sided mounting printed wiring board in which through holes are formed. Is a manufacturing method. First, the first
The manufacturing method will be described in detail with reference to the drawings. A ₁
In the step, the metal thin film 12 is formed over substantially the entire surface of the flat conductive substrate 11 (FIG. 1).
The metal thin film 12 is usually formed by a plating method regardless of electrolytic plating or electroless plating.

The conductive base material 11 used in the A ₁ step is a single plate having rigidity, for example, an effective dimension of 122 or less.
It is composed of a flat plate of an appropriate size in the range of 0 × 1020 mm and a thickness of 1 to 10 mm. For example, when the metal thin film 12 is formed here by electrolytic plating, chemical resistance and electrolytic corrosion resistance against chemicals used at that time are provided. It is desirable to have such a material, and examples thereof include a stainless steel plate (preferably SUS630 that has been subjected to a hardening treatment), a nickel plate, a titanium plate or a titanium alloy plate, a copper plate or a copper alloy plate, and the like.

The surface of the conductive base material 11 is subjected to a pretreatment for removing dirt and an oxide film and giving the surface a desired roughness. That is, the surface of the conductive substrate 11 is 0.08
It is desirable to polish with a roughness in the range of to 0.23 μm.
The surface roughness of the conductive base material 11 is the density strength of the metal thin film 12 formed on the conductive base material 11 to the surface of the conductive base material, the state of pinholes in the metal thin film 12, and the metal thin film 1
2 also affects the surface roughness. Further, the above-described roughness regulation range does not separate from the conductive base material 11 when the conductive metal layer described later is formed in the A ₂ step, and the conductive base material 11 and the metal are not separated from the conductive base material 11 in the transfer step of the A ₄ step described later. The adhesiveness is set so that the thin film 12 can be easily peeled off.

When the electrolytic plating method is applied to form the metal thin film 12 on the surface of the conductive substrate 11, the so-called high-speed plating method is suitable as the plating method. The metal thin film 12 is preferably a copper thin film or a nickel thin film having a thickness of 3 μm or less. Here, in the high-speed plating method, the conductive base material 11 is used as a cathode, flat plate-shaped insoluble anodes are arranged facing each other at a predetermined interval, and electrolytic solution is caused to flow at high speed between both electrodes to perform electrolytic plating. Is the way to do it.

For example, as a high-speed plating condition for forming a copper thin film as the metal thin film 12, a plating bath at 45 to 70 ° C. is in a turbulent state on the surface of the cathode (conductive substrate 11), that is, an interelectrode distance of 3 -30 mm, supply so that the contact speed of the plating bath to the electrode is 2.6 to 2.0 m / sec. At this time, as the plating bath, for example,
Use a copper sulfate plating bath, copper pyrophosphate plating bath, etc., and set the rate of formation of the copper thin film to 25 to 100 μm / min by applying a current at a cathode current density of 0.15 to 4.0 A / cm ^2. It is desirable to do.

When forming a nickel thin film as the metal thin film 12, the conditions for high-speed plating are that the cathode and the anode are separated by 300 to 350 mm, and the distance between the electrodes is 40 to 48 mm.
It suffices to supply a plating bath at ℃ and stir the air. At this time, as the plating bath, for example, nickel sulfate, nickel sulfamate, or the like is used, and the cathode current density is 2.2 to 4.0.
A current is applied at A / cm ² and the nickel film formation rate is 0.8.
It is preferable to set to be about 1.5 μm / min.

In the case of the conductive base material 11 such as a stainless steel plate or a nickel plate, there are defects such as intermetallic compounds, non-metallic inclusions, segregation, and pores on the surface thereof. Defects are introduced and mixed during melting or rolling, and cannot be eliminated only by the above-mentioned surface treatment of the conductive base material 11. These defects cause pinholes in the conductor metal layer described later.
However, in the case of the A ₁ step, the surface of the metal thin film 12 formed on the surface of the conductive base material 11 is electrochemically smooth, and therefore, a conductor metal layer, which will be described later, formed thereon has pinholes. Occurrence will not occur.

In step A ₂ , a conductor metal layer including a conductor circuit portion and a mounting terminal portion is formed. First, as shown in FIG. 2, the resist is applied to the other surface (non-formed portion) of the surface of the metal thin film 12 excluding the portions to be the conductive circuit portion forming portion 14 and the mounting terminal portion forming portion 15. By covering with a mask 13, patterns of conductor circuits and mounting terminals are formed. The resist mask 13 may be formed by a conventionally known photoresist method, printing method, or the like.

Then, as shown in FIG. 3, a conductor metal such as copper is deposited on the conductor circuit pattern forming portion 14 and the mounting terminal pattern forming portion 15 by a plating method to form a conductor circuit. Portion 14a and mounting terminal portion 1
A conductor metal layer 16 composed of 5a is formed. The plating method applied in this case may be either an electrolytic plating method or an electroless plating method.

When the conductor metal layer 16 is formed of copper, the electrolytic plating method in this step may be an ordinary plating method, but is preferably the high speed plating method described in the step A ₁ . The plating bath used in the high-speed plating method has a copper concentration of 0.20 to 2.0 mol / l, preferably 0.35.
A copper sulfate plating bath containing ˜0.98 mol / l and a sulfuric acid concentration of 50 to 220 g / l is desirable, and further, CUPPORAPID H manufactured by LPW Co., Ltd. in West Germany to ensure uniform plating.
It is preferable that 1.5 ml / l of s (trade name) is added. Further, a usual plating bath such as copper pyrophosphate solution may be used. The current density is 0.15-4A / cm ² , the liquid contact speed of the plating bath to the electrode is 2.6-20m / sec,
The bath temperature is set to 45 to 70 ° C., preferably 60 to 65 ° C., respectively.

In the A ₃ step, the conductor metal layer 16 formed on the surface of the metal thin film 12 in the steps up to the A ₂ step is integrated with the insulating base material. First, as shown in FIG. 4, only the resist mask 13 is removed from the surface composed of the resist mask 13 and the conductor metal layer 16, and the conductor metal layer 16 is left in a state of protruding from the surface of the metal thin film 12. .

Specifically, the surface is sprayed with a solution that dissolves only the resist mask 13 such as caustic soda, or the plate body of FIG. 3 obtained in step A ₂ is immersed in the solution. do it. Then, as shown in FIG. 5, the surface of the conductor metal layer 16 is pressure-bonded or heat-pressure bonded to one surface of the insulating base material 17 to integrate the whole.

The insulating base material 17 may be either an organic material or an inorganic material as long as it is electrically insulating. For example, glass, epoxy resin, phenol resin, polyimide resin, polyester resin, aramid resin. Materials such as can be used. Further, a conductive material such as iron or aluminum coated with enamel on the surface to make it insulating, or an aluminum surface subjected to alumite treatment to make the surface insulating may be used. In this A ₃ step, generally, a prepreg obtained by impregnating a glass cloth or the like with an epoxy resin to make it into a semi-cured state (B stage state) is used.
It is preferable that the conductor metal layer 16 protruding from the surface of the metal thin film 12 is adhered and integrated with this in a state of being immersed (state as shown in FIG. 5).

Prior to carrying out this A ₃ process, A ₂
If the surface of the conductor metal layer 16 in the state shown in FIG. 3 of the process is roughened, the adhesion with the insulating base material 17 is improved, which is preferable. As a roughening method in this case, it is preferable to perform electrolytic plating on the surface of the conductor metal layer 16 as a cathode.

As the plating conditions at this time, the current density is 0.26 to 0.85 A / cm ² , and the distance between the electrodes is 26 to 50 m.
m, contact speed of the plating bath to the electrode is 0.6 to 1.5 m
/ sec, and the plating bath is not particularly limited, for example, copper sulfate 80 to 15
A mixed solution of 0 g / l, sulfuric acid 40 to 80 g / l, and potassium nitrate 25 to 50 g / l may be used.

By the roughening treatment performed under such conditions,
On the surface of the conductor metal layer 16, a precipitate having an average particle size of 1 to 5 μm is projected and electrodeposited, and the adhesion with the insulating base material 17 is improved. When the roughened surface of the conductor metal layer 16 after the above-mentioned roughening treatment is subjected to the chromate treatment, the affinity between copper and the resin or adhesive in the insulating base material 17 increases, and not only the peeling strength but also the peeling strength. Therefore, there is an advantage that the heat resistance (for example, solder heat resistance) of the conductor metal layer 16 is improved by about 15%. This chromate treatment is specifically 0.7-12g
It may be dipped in a potassium dichromate solution having a concentration of 1 / l at room temperature for 5 to 45 seconds or subjected to chromate treatment with a commercially available electrolytic chromate treatment liquid.

In the A ₄ step, only the conductive base material 11 is peeled off from the integrated product (shown in FIG. 5) obtained in the A ₃ step, and the wiring board material for single-sided mounting used in the subsequent steps is obtained. Manufactured. In this wiring board material, as shown in the sectional view of FIG. 6 and the partial plan view of FIG. 7, a conductor metal layer 16 including a conductor circuit portion 14a and a mounting terminal portion 15a is embedded on one surface of an insulating base material 17. The transferred surface is a flash surface covered with the transferred transfer metal thin film 12 '.

The step A ₅ is the most important step in the method of the present invention. In this step, a resist layer, that is, an etching layer in this case, is left on the surface of the transfer metal thin film 12 ′ except for the area described later. The dual plating resist layer 18 is formed. That is, as shown in the cross-sectional view of FIG. 8 and the partial plan view of FIG. 9, a portion of the surface of the transfer metal thin film 12 ′ that corresponds to the portion where the mounting terminal portions 15 a and 15 a are formed and surrounds this portion. The etching / plating resist layer is formed by covering the surface portion 12'a except the region 19 with a resist mask.

In this case, the area 19 may be of any suitable size, as long as it does not include a portion corresponding to the conductor circuit portion 14a adjacent to the mounting terminal portion 15a. Therefore, part 1 of the transferred metal thin film 12 '
2'b is exposed from the region 19, and the remaining portion 12'a is entirely covered with the etching / plating resist layer 18.

The step A ₆ is a step of exposing the surface of the mounting terminal portion 15a. That is, as shown in the sectional view of FIG. 10 and the partial plan view of FIG. 11, the transfer metal thin film portion 12′b exposed from the region 19 in which the mounting terminal portion 15a shown in FIG. 8 is present is removed by etching. To do. The surface 15b of the mounting terminal portion 15a and the surface 17a of the insulating base material 17 are exposed.

The tail portion 15c of the mounting terminal portion 15a has a region 19
Since it is integrated with the remaining portion 12'a of the transferred metal thin film outside the frame of No. 3, the mounting terminal portion 15a has the remaining portion 1 '.
Power can be supplied from 2'a. As shown in the sectional view of FIG. 12 and the partial plan view of FIG. 13, the A ₇ process is different from the constituent metal of the mounting terminal part on the surface 15b of the mounting terminal part exposed by the A ₆ process. This is a step of forming the mounting terminal metal layer 20 made of the same kind of metal or alloy. The mounting terminal metal layer 20 is usually composed of solder different from the constituent metal of the mounting terminal portion. However, in order to simply contact the mounting terminal portion with the inspection terminal or to connect with the terminal of the liquid crystal module,
It may be a similar metal or alloy.

When the mounting terminal metal layer 20 is formed, an electrolytic plating method is used in which electricity is supplied from the remaining portion 12'a of the transfer metal thin film. When the metal to be plated is solder, the solder plating bath used is preferably a borohydrofluoric acid-based plating bath, for example, HBF ₄ concentration 2
30 to 250 g / l, Sn ²⁺ 11.5 to 13.5 g / l, P
b ²⁺ 8.0 to 10.0 g / l composition bath can be mentioned. Further, the current density at this time is preferably 0.5 to ^{2 A} / dm ² .

Metal layer 2 for mounting terminals in this A ₇ process
0 is the surface 15b and the tail portion 15c of the mounting terminal portion 15a.
Is formed only on the surface, and the surface is smooth, and its thickness is uniform at all points. Then, the thickness of the mounting terminal metal layer 20 can be appropriately changed by changing the plating time. A ₈ step, after the end of A ₇ steps, are successively removed with etching and plating resist layer 18 remaining portion 12'a of the transfer metal thin to expose the conductor circuit, a printed wiring board of a single-sided mounting of interest It is a process to do.

That is, as shown in the sectional view of FIG. 14 and the partial plan view of FIG. 15, first, the etching / plating resist layer 18 shown in FIGS. 12 and 13 is removed by etching with an appropriate etchant. Then, as shown in the sectional view of FIG. 16 and the partial plan view of FIG. 17, the remaining portion 12′a of the transferred metal thin film is removed by etching with another appropriate etchant.

Thus, a printed wiring board having the mounting terminals having the mounting terminal metal layer 20 formed on the surface of the mounting terminal portion 15a and the conductor circuit portion 14a on the flash surface can be obtained. Next, an improved method effective for solving the following problems in the above-mentioned first manufacturing method will be described.

That is, when the mounting terminal metal layer 20 is formed on the surface 15b of the mounting terminal portion by electrolytic plating in the step A ₇ (FIGS. 12 and 13) of the first manufacturing method, the remaining portion of the transferred metal thin film is formed. Since the current is supplied from 12'a, the metal to be plated is not only electrodeposited on the surface 15b of the mounting terminal portion 15a, but also the edge portion 12 of the remaining portion 12'a of the transferred metal thin film as shown in FIG. Also electrodeposited on'c.

[0039] Thus, A ₈ etched in step and the plating resist layer 18, removal of the remaining portion 12'a of the transfer metal thin film, as shown in the partial plan view of a cross-sectional view and FIG. 19 in FIG. 18, the region 19 Along the circumference, a layer 20 'of the same metal as the mounting terminal metal remains in a frame shape. The frame-shaped metal layer 20 'will be removed later by, for example, brushing.

The improved manufacturing method is a method for preventing the generation of the frame-shaped metal layer 20 'described above. In this method, the process up to step A ₆ is performed in the same manner as in the first manufacturing method to expose the surface 15b of the mounting terminal portion 15a as shown in FIGS. In this method, the resist agent used for forming the region 19 in the step A ₅ may be the etching / plating resist agent used in the first manufacturing method, but it is simply the etching resist agent. May be

Hereinafter, the case where the etching resist is used in the step A ₅ will be described. A ₆ process after the end of, first,
As A ₆ -1 step, as shown in the partial plan view of a cross-sectional view and FIG. 21 in FIG. 20, the etching resist layer 18 is removed to expose the remaining portion 12'a of the transfer metal thin film. Then A as _6-2 step, to form a plating resist layer 21 for surface and the mounting terminal metal layer covers the edge 12'c of the remainder 12'a of the transfer metal thin film mentioned above.
Therefore, in this A ₆ -2 step, the mounting terminal portion 15a and the area 19 'surrounding it are slightly narrower than the area 19 (FIGS. 8 and 9) formed in the A ₅ step.

After the completion of the A ₆ -2 step, as in the case of the first manufacturing method, the step is transferred to the A ₇ step, and the mounting terminal metal layer is formed on the surface 15b of the mounting terminal portion by electrolytic plating. It is formed. In this electrolytic plating, the edge portion 12'c of the remaining portion 12'a of the transferred metal thin film is covered with the plating resist layer 21, so that the mounting terminal metal is not electrodeposited there. The problem that the frame-shaped metal layer 20 'remains as shown by 19 is solved.

Next, the second manufacturing method will be described. The B ₁ process and the B ₂ process in the second manufacturing method are respectively the first
This is the same as the A ₁ step and the A ₂ step in the manufacturing method of.
As shown in FIG. 24, the step B ₃ is a step of pressure-bonding or thermocompression-bonding the conductor metal layers 16 manufactured in the step B _{2 on} both surfaces of the insulating base material 17 to integrate them.

The type and type of insulating base material 17 used in this step
The conditions for body formation are described in A above. ₃Same as the process
Good. B_FourThe process is B₃Integrated product obtained in the process (Fig.
24), only the conductive substrate 11 is peeled and removed.
Manufactures wiring board materials for double-sided mounting used in subsequent processes
It is a process to do.

In this material, as shown in FIG. 25, the conductor metal layer 16 and the metal thin film 12 are transferred to both surfaces of the insulating base material 17, so that both surfaces thereof are transferred metal thin film 12 '.
Has become a flash surface. The step B ₅ is a step of forming a hole for a through hole and imparting conductivity to the surface thereof.

That is, as shown in FIG. 26, a through-hole 22 is formed by penetrating a predetermined conductor circuit portion,
Then, for example, chemical copper is deposited on the surface 22a of the through hole 22 by electroless plating to form the conductive layer 23. B ₆ was performed with a step corresponding to A ₅ step in the first manufacturing method, the mounting terminal portion to form an etching resist layer 24 is a region 19 underlying is formed on the surface of the transfer metal thin film 12 '. The resist agent used may be the etching / plating resist agent used in the first manufacturing method.

At this time, the etching resist layer 24 is formed so as to block the opening 22b of the through hole hole 22.
Are formed (FIG. 27). A dry film is usually used for forming the etching resist layer 24. In the B ₇ step, as shown in FIG. 28, the transfer metal thin film existing in the region 19 is removed by etching with an appropriate etchant that dissolves it, and the surface 15b of the mounting terminal portion 15a is removed.
Is a step of exposing.

At this time, since the opening 22b of the through-hole 22 is blocked by the etching resist layer 24, the etchant does not enter the through-hole 22. Therefore, the conductive layer 23 deposited and formed on the surface 22a of the through-hole 22 remains as it is without being etched. B ₈ step, as shown in FIG. 29, by removing the etching resist layer 24, a step of exposing the remaining portion 12'a of the transfer metal thin film.

The step B ₉ is a step of forming a plating resist layer by coating the remaining portion of the transfer metal thin film exposed in the step B ₈ . The plating resist layer 25 at this time is
As shown in FIG. 30, the remaining portion 12'a of the transferred metal thin film
Is formed so as to cover the surface and the edge portion 12'c, but is formed so as not to block the opening portion 22b of the through hole hole in the remaining portion where the through hole hole 22 is formed.

The step B ₁₀ is the step A ₇ in the first manufacturing method.
It is a process corresponding to the process. In this step, as shown in FIG. 31, a metal or alloy of a different kind or the same kind as the metal forming the mounting terminal portion is electrodeposited on the surface 15b of the mounting terminal portion 15a by electrolytic plating, and the mounting terminal metal layer 20 is formed. However, at the same time, the same kind of metal is electrodeposited on the conductive layer 23 of the through-hole 22.
0 is formed and becomes a plated through hole.

In the step B ₁₁ , first, the plating resist layer 2
5 is removed, and the remaining portion 12'a of the transferred metal thin film is continued.
Are removed to expose the conductor circuit. As a result, as shown in FIG. 32, the mounting terminal metal layer 20 is formed on the mounting terminal portion 15a to form a mounting terminal, and the same kind of metal layer 20 is also formed on the surface of the through hole. A printed wiring board for double-sided mounting is obtained.

In the first and second methods described above, the mounting terminal metal layer may be formed on the independent mounting terminal portion as follows. That is, first, when designing the wiring of the conductor circuit portion and the mounting terminal portion, the independent mounting terminal portion is designed to have a shape having a lead portion having a normal length of about 0.2 to 1.0 mm. Therefore, when the transfer process of the A ₄ process is completed, as shown in FIG. 33, the lead part 15 ′ c extends like a tail under the flash transfer metal thin film 12 ′, and the independent mounting terminal part 15 is formed. 'a is located.

Then, when the region 19 is formed by the etching / plating resist layer or the etching resist layer 18 in the A ₅ step, as shown in FIG. 34, the lead portion 15'c of the independent mounting terminal portion is crossed. Region 1 in shape
9 is formed. Thereafter, in the A ₆ step, the transfer metal thin film portion 12′b in the region 19 is removed, and the surfaces 15b and 15′b of the mounting terminal portion 15a and the independent mounting terminal portion 15′a are removed as shown in FIG.
Expose as indicated at 5.

At this time, since the end of the lead portion 15'c of the independent mounting terminal portion 15'a is connected to the remaining portion 12'a of the transferred metal thin film, the remaining portion 12'a leads to the lead portion 1 '.
The independent mounting terminal portion 15'a can be energized through the end of 5'c. That is, the mounting terminal metal layer can be formed on the surface 15′b of the independent mounting terminal portion by the electrolytic plating method.

In the first and second manufacturing methods described in detail above, when the transfer metal thin film portion in the region 19 is removed by etching to expose the surface 15b of the mounting terminal portion 15a (the first method is used). a ₆ step if, in B ₇ step) in the third method, not only simply etching away portions of the transfer metal thin film, and thin the thickness and the etching portion of the further mounting terminal portions 15a, After that, a metal for a mounting terminal is electrodeposited thereon to manufacture a printed wiring board in which the entire smooth circuit surface or the mounting terminal is recessed from the entire surface.

The manufacturing method will be described for the case of the first manufacturing method. That is, in the step A ₆ shown in FIG. 10, the transfer metal thin film portion 12′b in the region 19 is removed by etching, and then further etching is performed to remove the conductive metal on the surface portion of the mounting terminal portion 15a by etching. Then, the mounting terminal portion 15a having a thinner layer than in the case of FIG.
To Therefore, in the region 19, the mounting terminal portion 15
As shown in FIG. 36, a is in a depressed state.

Then, in step A ₇ , a mounting terminal metal is electrodeposited on the surface of the mounting terminal portion 15a by electrolytic plating. At this time, since the thickness of the metal layer can be adjusted by controlling the plating time, the surface 20a of the metal layer 20 and the surface 17a of the insulating base material 17 are flush with each other as shown in FIG. If it is plated so as to form a smooth circuit. Also, FIG.
As shown in FIG. 6, if the thickness of the metal layer 20 is reduced, the surface 20a of the metal layer 20 may be recessed more than the surface 17a of the insulating base material 17 to form a circuit.

Particularly, in the latter concave circuit, when the component is surface-mounted, the terminal of the mounted component does not shift even if the terminal is located in the concave circuit and the whole swings slightly. This is preferable because it enables surface mounting with extremely high reliability.

[0059]

Examples of the invention

Example 1 A printed wiring board was manufactured in the following steps by the first manufacturing method. 1) Step A ₁ SUS 6 which has been subjected to a hardening treatment as the conductive base material 11.
Thirty single plates were prepared, and the surface thereof was subjected to polishing treatment using a rotary feather cloth polishing device with oscillation to obtain a surface roughness of 0.1 μm. Then, using a copper sulfate plating bath with a sulfuric acid concentration of 200 g / l and a copper concentration of 0.5 mol / l, the distance between the electrodes was 4 mm,
High-speed plating was performed at a current density of 0.8 A / cm ² and a liquid contact speed of 7 m / sec to form a copper thin film 12 having a thickness of 3 μm.

2) Step A _{2 On} the surface of the copper thin film formed in the step A ₁ , a conductive film and a mounting terminal pattern 13 are formed by a resist mask having a thickness of 40 μm using a dry film as a resist agent (FIG. 2). Sulfuric acid concentration 100g / l, copper concentration 0.5mol /
Using a copper sulfate plating bath of l, distance between poles: 11 mm, current density
High-speed plating was performed under the conditions of 0.2 A / cm ² and a liquid contacting speed of 7 m / sec, and a copper layer having a thickness of 35 to 40 μm was formed as a conductor circuit layer 16 at a portion other than the resist mask pattern 13 (FIG. 3). Then, Nogera plating is performed using a mixed solution of 100 g / l of copper sulfate, 50 g / l of sulfuric acid, and 30 g / l of potassium nitrate, and the thickness of the conductor circuit layer is set to 3
The surface was roughened by depositing copper with a thickness of μm.

3) Step A _{3 The} plate obtained in the step A ₂ is immersed in a stripping solution composed of a 2% caustic soda aqueous solution, the resist mask 13 is stripped and removed, and the conductor circuit section 14a and the mounting terminal section 15a are removed. Was left (Fig. 4). Then, an insulating base material 17 made of a glass fiber-epoxy resin plate (trade name: GFPL-170 manufactured by Mitsubishi Gas Chemical Co., Inc.) was brought into contact with the surface of the conductor circuit layer 16, and the whole was heated to a temperature of 1
Thermocompression bonding was performed at 70 ° C. and a pressure of 25 kg / cm ² to obtain an integrated product (FIG. 5).

4) Process A _{4 From} the integrated product obtained in process A ₃ , a single plate of SUS630 1
Only 1 was peeled off. One surface of the glass fiber-epoxy resin plate was covered with the transferred copper thin film 12 '(FIGS. 6 and 7). The pitch spacing between the mounting terminal portions 15a and 15a and the pitch spacing between the mounting terminal portion 15a and the conductor circuit portion 14a are both designed to be 0.5 mm.

5) A ₅ step Surrounding the mounting terminal portions 15a, 15a, the length is 1.5 mm, and the width is 1
A dry film with a thickness of 40 mm (trade name: Fuji Film A) that can be used for both etching and solder plating on the surface of the transfer metal thin film 12 ′ excluding the rectangular area 19 of 2.5 mm.
640) to form a resist layer 18 (FIG. 8,
(Figure 9).

6) Step A ₆ 43.3 g / l of Cu (NH ₃ ) ₄ Cl solution is used as an etchant to remove the exposed portion of the transferred copper thin film from the region 19 by etching to remove the mounting terminal portion 15a, 15a surface 15
b and 15b were exposed (FIGS. 10 and 11). 7) The remaining portion 12'a of A ₇ step transferring the thin copper film 12 'and the cathode, contains no ^{fluoride, Sn 2+ 12~20g / l, Pb} +2 8~13
Current density of 1.5A / using solder plating bath consisting of g / l
Solder plating with dm ² and mounting terminal surface 15b, 1
Solder plating layers 20 and 20 having an average thickness of 15 μm were formed on 5b (FIGS. 12 and 13).

8) Step A _{8 The} resist layer 18 was peeled off using about 2% caustic soda solution (FIGS. 14 and 15), and further 43.3 g / l of Cu (NH ₃ ) _{4 was} added.
The residual portion 12'a of the transferred copper thin film was removed by etching using a Cl solution to expose the conductor circuit (FIGS. 16 and 1).
7). On the mounting terminal portions 15a, 15a, the solder plating layer 20 having a uniform thickness without any positional deviation,
20 were formed. That is, the mounting terminals having a narrow pitch with a pitch interval of 0.5 μm were formed.

Although the frame-shaped solder plating layer 20 'as shown in FIGS. 18 and 19 was formed along the edge of the region 19, this can be easily removed during the entire brushing process. I was able to. Example 2 Up to the A ₆ step, the same steps as in Example 1 were performed, and the surfaces 15b, 15 of the mounting terminal portions 15a, 15a were formed in the region 19.
b was exposed (FIGS. 10 and 11).

1) Step A ₆ -1 Then, a resist layer 18 is formed using ca. 2% caustic soda solution.
Was removed to expose the remaining portion 12'a of the transferred copper thin film (FIGS. 20 and 21). 2) Step A ₆ -2 Remaining part 1 of the transferred copper thin film exposed in step A ₆ -1
The surface of 2'a and the edge portion 12'c were covered with a solder plating resist (trade name: Fuji Film A640) having a thickness of 40 μm to form a resist layer 21 (FIGS. 22 and 23).

At this time, the area 19 in which the mounting terminal portion is present is provided.
Is slightly narrowed to region 19 '. Then, the A ₇ step and the A ₈ step are performed in the same manner as in Example 1, and
As shown in FIG. 7, mounting terminals with a narrow pitch (pitch 0.15 mm) were formed. In the second embodiment, the first embodiment
Since the frame-shaped solder plating layer 20 'such as the above was not formed, its brushing was not necessary at all.

Example 3 In the same manner as in Example 1, the conductor metal layer 16 as shown in FIG. 4 was formed, and this was applied to both surfaces of the insulating base material 17 used in Example 1 under the condition of A ₃ process. After thermocompression bonding to manufacture an integrated product as shown in FIG.
A wiring board material for double-sided mounting as shown in 5 was manufactured.
At this time, the pitch between the mounting terminal portions and the distance between the mounting terminal portion and the conductor circuit portion are both designed to be 0.15 mm.

1) Step B _{5 In} the material obtained in Step B ₄ , an electric drill was used to form through-holes 22 having a hole diameter of 0.4 mm, and then electroless plating was performed to form the through-holes 22. Chemical copper was deposited on the wall surface to give conductivity to the surface 22a (FIG. 26). 2) B ₆ step then the surface of the transfer thin copper film except the region 19 of the same size as in Example 1, the mounting terminal portions underlying, also blocked the opening 22b of the hole for the through-holes, resist An etching resist layer 24 having a thickness of 40 μm was formed from the agent (trade name: Fuji Film A640) (FIG. 27).

3) Step B ₇ The portion of the transferred copper thin film exposed from the region 19 was used in Example 1.
The surface of the mounting terminal portions 15a, 15a was exposed by etching away with the copper etchant used in the A ₈ step (FIG. 28). 4) Step B _{8 The} etching resist layer 25 was stripped and removed using caustic soda solution of about 2% to expose the remaining portion 12′a of the transferred copper thin film, and at the same time, the opening 22b of the through hole hole 22 was opened ( 29).

5) Process B ₉ Next, the surface of the remaining portion 12'a of the transferred copper thin film and the region 19 are formed.
The edge portion 12'c that forms the edge of is coated with a resist agent for solder plating (trade name: Fuji Film A640) to have a thickness of 4
A plating resist layer 25 having a thickness of 0 μm was formed (FIG. 30).
The area 19 'formed surrounding the mounting terminal portion is only about 0.2 mm smaller in length and width than the area 19.

6) Process B ₁₀ Solder plating is performed under the same conditions as in process A _{7 of} Example 1, and the solder plating layer 20 having a thickness of 10 to 15 μm is formed on the surface 15 b of the mounting terminal portion and the surface of the through hole 22. Were formed (FIG. 31). 7) first removing the plating resist layer 25 in the B ₁₁ step sodium hydroxide, and then to expose the conductive circuit to remove the remaining portion 12'a of the transfer thin copper film with an etchant used in the A ₆ step of Example 1 ( 32).

Thus, the solder plating layer 20 having a uniform thickness which does not cause the positional deviation from the mounting terminal portion 15a is formed, and the mounting terminal having a narrow pitch (0.15 mm) is provided, and the through hole is also soldered. A printed wiring board for double-sided mounting having a plated layer was obtained.

[0075]

As is apparent from the above description, according to the method of the present invention, the mounting terminal metal layer such as solder formed on the mounting terminal portion is formed by the electrolytic plating method. Positional displacement does not occur between the terminal portion and the mounting terminal metal layer. The area formed around the mounting terminal portion only needs to surround the mounting terminal portion, so that the area thereof may be any suitable size, and no particular dimensional accuracy is required. Therefore, pitch 0.
Narrow-pitch mounting terminals of 5 mm or less can be reliably formed, and their industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a metal thin film is formed on the surface of a conductive base material.

FIG. 2 is a cross-sectional view showing a state where a resist mask is formed on a metal thin film.

FIG. 3 is a cross-sectional view showing a state in which a conductor metal layer is formed.

FIG. 4 is a cross-sectional view showing a state in which the resist mask is removed and the conductive metal layer is projected.

FIG. 5 is a cross-sectional view showing a state in which a conductor metal layer is integrated with an insulating base material.

FIG. 6 is a cross-sectional view of a wiring board material for single-sided mounting in which a conductive base material is peeled off from the integrated body of FIG.

7 is a partial plan view of the wiring board material of FIG.

FIG. 8 is a cross-sectional view showing a state in which an etching / plating resist layer is formed on a transfer metal thin film to form a region surrounding a mounting terminal portion.

9 is a partial plan view of the material of FIG.

FIG. 10 is a cross-sectional view showing a state in which the transfer metal thin film in the region surrounding the mounting terminal portion is removed to expose the surface of the mounting terminal portion.

11 is a partial plan view of the material of FIG.

FIG. 12 is a cross-sectional view showing a state in which a mounting terminal metal layer is formed on the surface of a mounting terminal portion.

13 is a partial plan view of the material of FIG.

FIG. 14 is a cross-sectional view showing a state where the etching / plating resist layer is removed.

FIG. 15 is a partial plan view of the material of FIG.

FIG. 16 is a cross-sectional view showing a single-sided mounting printed wiring board of the present invention obtained by removing the remaining portion of the transferred metal thin film.

FIG. 17 is a partial plan view of the printed wiring board of FIG.

FIG. 18 is a cross-sectional view showing a printed wiring board on which a frame-shaped metal layer is formed.

19 is a partial plan view of the printed wiring board of FIG.

FIG. 20 is a cross-sectional view showing a state in which the etching resist layer is removed by the improved method of the first manufacturing method.

21 is a partial plan view of the material of FIG. 20. FIG.

FIG. 22 is a cross-sectional view showing a state in which a plating resist layer is formed on the surface of the remaining portion of the transferred metal thin film and the edge thereof by the improved method of the first manufacturing method.

FIG. 23 is a partial plan view of the material of FIG. 22.

FIG. 24 is a cross-sectional view showing a state in which conductor metal layers are integrated on both surfaces of an insulating base material.

FIG. 25 is a cross-sectional view showing a state where the conductive base material is peeled off from the integrated product of FIG. 24.

FIG. 26 is a cross-sectional view showing a state in which a through hole is provided and conductivity is added to the hole.

FIG. 27 is a cross-sectional view showing a state in which an etching resist layer is formed on a transfer metal thin film to form a region surrounding a mounting terminal portion.

FIG. 28 is a cross-sectional view showing a state in which the transfer metal thin film in the region surrounding the mounting terminal portion is removed to expose the surface of the mounting terminal portion.

FIG. 29 is a cross-sectional view showing a state where the etching resist layer is removed to expose the remaining portion of the transferred metal thin film.

FIG. 30 is a cross-sectional view showing a state in which a plating resist layer is formed by covering the surface and the edge of the remaining portion of the transferred metal thin film.

FIG. 31 is a cross-sectional view showing a state in which a mounting terminal metal layer is formed on the surface of the mounting terminal portion.

FIG. 32 is a cross-sectional view of the double-sided mounting printed wiring board according to the present invention by the second manufacturing method.

FIG. 33 is a partial plan view of a wiring board material having an independently mounted terminal portion.

34 is a partial plan view showing a state in which a region surrounding the mounting terminal portion is formed in the material of FIG. 33. FIG.

FIG. 35 is a partial plan view showing a state in which the surface of the mounting terminal portion is exposed in the area of FIG. 34.

FIG. 36 is a cross-sectional view showing a state where the surface of the mounting terminal portion is recessed by increasing the amount of etching.

FIG. 37 is a cross-sectional view showing a state in which the surface of the mounting terminal is flush with the surface of the insulating base material.

FIG. 38 is a cross-sectional view showing a state in which the surface of the mounting terminal is recessed from the surface of the insulating base material.

FIG. 39 is a cross-sectional view showing a state in which the conductor metal layer and the metal thin film are transferred to the insulating base material in the conventional method.

40 is a cross-sectional view showing a state in which a resist mask is formed on the surface of the material shown in FIG. 39.

FIG. 41 is a cross-sectional view showing a state in which a mounting terminal metal layer is formed.

FIG. 42 is a cross-sectional view showing a state where the resist mask is removed.

FIG. 43 is a cross-sectional view of a single-sided mounting printed wiring board obtained by a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insulation base material 2 Conductor circuit part 3 Mounting terminal part 3a Edge part of mounting terminal part 4 Metal thin film 5 Resist layer 5a Edge part of resist layer 6 Solder layer 11 Flat conductive base material 12 Metal thin film 12 'Transfer metal thin film 12' a Remaining portion of the transferred metal thin film 12'b A portion of the transferred metal thin film exposed in the region 19 12'c Edge of the transferred metal thin film 13 Resist mask 14 A portion where a conductor circuit portion is formed 14a Conductor circuit portion 15 Mounting terminal portion Part to be formed 15a Mounting terminal portion 15b Surface of mounting terminal portion 15a 15c Tail portion of mounting terminal portion 15a 15'a Independent mounting terminal portion 15'b Surface of independent mounting terminal portion 15'a 15'c Independent mounting terminal portion 15'a Lead part 16 Conductor metal layer 17 Insulating base material 17a Surface of insulating base material 18 Etching / plating resist layer, etching resist layer 19 Transfer metal surrounding mounting terminal part 15 Area formed on thin film 19 'Area surrounded by plating resist layer 21 Metal layer for mounting terminals 20' Frame-shaped metal layer 21 Plating resist layer 22 Through hole hole 22a Through hole surface 22b Through Hole openings 23 Conductive layer (chemical copper) 24 Etching resist layer 25 Plating resist layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Murakami 5-14-15 Oue, Ayase City, Kanagawa Prefecture Nakou Denshi Kogyo Co., Ltd. (72) Inventor Toshiro Miki 1-14-1 Shimbashi, Minato-ku, Tokyo Toagosei Chemical Industry Co., Ltd.

Claims (2)

[Claims] 1. A step of forming a metal thin film on the surface of a flat conductive substrate; a conductor circuit is formed by covering a portion of the surface of the metal thin film where a conductor circuit portion and a mounting terminal portion are not formed with a resist mask. After forming a pattern of the mounting terminal, a step of forming a conductive metal layer on the formation portion of the pattern of the conductive circuit and the mounting terminal by plating; after removing the resist mask, insulating the surface of the conductive metal layer A step of pressure-bonding or heat-pressing the base material to integrate them;
A step of transferring the conductor metal layer and the metal thin film to one surface of the insulating base material to obtain a wiring board material by peeling and removing only the flat conductive base material from the obtained integrated product; A step of forming a resist layer by covering a surface portion of the surface of the transfer metal thin film except a surface portion corresponding to a portion where the mounting terminal portion is formed and a region having a desired area surrounding the mounting terminal portion with a resist mask; A step of exposing the surface of the conductive metal layer of the mounting terminal section by etching away the portion of the transfer metal thin film located in the area where the terminal section is present; by electrolytic plating on the surface of the conductive metal layer of the mounting terminal section. A step of electrodepositing a metal or an alloy different from or the same as the conductor metal of the conductor metal layer to form a mounting terminal metal layer; and the remaining portion of the resist layer and the transfer metal thin film. Method for manufacturing a printed wiring board, characterized by comprising as essential step; step of exposing the conductor circuit are sequentially removed. 2. A step of forming a metal thin film on the surface of a flat conductive substrate; a conductor circuit is formed by covering a portion of the surface of the metal thin film where the conductor circuit portion and the mounting terminal portion are not formed with a resist mask. After forming a pattern of the mounting terminal, a step of forming a conductive metal layer on a portion where the pattern of the conductive circuit and the mounting terminal is formed by plating; after removing the resist mask, insulating the surface of the conductive metal layer A step of pressure-bonding or heat-pressure-bonding to both sides of the base material to integrate them; by removing only the flat conductive base material from the obtained integrated product, the conductor metal layer and the metal are provided on both sides of the insulating base material. The step of transferring a thin film into a wiring board material; forming a through hole at a predetermined position of the transfer metal thin film of the material, and then performing electroless plating on the surface of the through hole. A step of imparting electrical conductivity; a surface part of the surface of the transfer metal thin film of the material, excluding a surface part corresponding to the formation part of the mounting terminal part and a region of a desired width surrounding the surface part, and the through hole Forming an etching resist layer by covering the opening of the hole with a resist mask; etching away the portion of the transfer metal thin film located in the region in which the mounting terminal portion is present to remove the conductive metal layer of the mounting terminal portion. A step of exposing the surface; a step of removing the etching resist layer to expose a remaining portion of the transferred metal thin film; a surface of the remaining portion of the transferred metal thin film and an edge portion thereof, and an opening portion of the through hole hole Forming a plating resist layer without covering the conductor metal layer on the surface of the conductor metal layer of the mounting terminal and the surface of the through hole hole by electrolytic plating. Process a conductive metal by electrodeposition of heterogeneous or homogeneous metal or alloy to form a metal layer and a plated through-hole mounting terminal;
And a step of sequentially removing the remaining portion of the plating resist layer and the transfer metal thin film to expose the conductor circuit; as a requisite step.