JPH02113590A - Manufacture of printed-wiring board - Google Patents

Abstract

PURPOSE:To make it possible to deposit a rough surface-like plating even near fine patterns and a plated resist by a method wherein the roughened surfaces of conductor circuits are formed of a roughening plating using a copper sulfate plating solution containing a specified component. CONSTITUTION:At least one kind selected from among an oxyethylene surface active agent, a sulfer compound and a safranine dye is used as a component (a) and chloride ions are used as a component (b). At least roughened surfaces 5 of conductor circuits 4, which are formed on the surface of a temporary substrate 1 using a plated resist by a plating method, are formed of a roughening plating using a copper sulfate plating solution containing at least the component (a) out of the components (a) and (b). Thereby, the deposition property of the roughening plating is improved and the roughening plating is deposited in fine grooves, which are pinched by the plated resist, of the circuits and even near the plated resist.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a printed wiring board using a so-called transfer method.

[Conventional technology]

An example of a method for manufacturing a printed wiring board using the transfer method is shown in FIGS. 4(a) to 4(a).
is formed by plating (FIG. 4(a)).

Imaging the plating resist 3 on the metal thin film 2 (
(i.e., by covering the metal thin film 2 with a plating resist 3 so that the metal thin film 2 is exposed in the reverse pattern of the conductor circuit to be formed). , a conductor circuit 4 is formed by electroplating on the exposed metal thin film 2.
(Fig. 4(b)). In order to increase the adhesive strength of the conductive circuit 4, the surface of the conductive circuit 4 is roughened (FIG. 4(C)), and then the plating resist 3 is peeled off (FIG. 4(d)). This surface roughening treatment is done by electroplating.
This is done by forming a roughened plating film 5 on the surface of the conductor circuit 4. Next, the insulating layer material 7 is superimposed on the surface of the temporary substrate 1 on which the conductive circuit 4 is formed (FIG. 4(el)), and the conductive circuit 4 and the insulating layer 8 are formed by using a molding press (indicated by arrows A and B) or the like. and peel off the temporary substrate l (see Fig. 4).
f)). The printed wiring board 20 is obtained by removing the metal thin film 2 on the surface by etching or the like (FIG. 4(g)).

In this way, the method of manufacturing printed wiring boards using the transfer method, for example, eliminates the need for etching to form conductor circuits, so side etching of conductor circuits does not occur, and it is possible to create high-density, fine circuits. It is excellent in that it can form patterns. Moreover, a rough plating film 5 is formed on the bottom surface of the conductor circuit 4.
is formed, the adhesive force between the conductive circuit 4 and the insulating layer 8 is stronger than that in the case without the roughened plating film.

[Problem to be solved by the invention]

However, in the above-mentioned conventional method for manufacturing printed wiring boards, when the surface of the conductor circuit is roughened by electroplating, failure of deposition on the fine circuit pattern and failure of roughening plating at the edge of the plating resist occur. There was a problem. For this reason, the adhesive force between the conductor circuit and the insulating layer is weak, or a defective conductor circuit is formed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a printed wiring board that can improve the precipitation of rough plating even when it is adjacent to a fine pattern or a plating resist.

[Means to solve the problem]

In order to solve the above problems, the inventors focused on the composition of a plating solution (plating bath) that performs rough surface plating, studied a composition that could improve the above-mentioned precipitation defects, and completed the present invention.

Therefore, the method for manufacturing printed wiring according to the present invention is as follows:
At least the roughened surface of the conductor circuit formed on the surface of the temporary substrate by a plating method using a plating resist is obtained by using a copper sulfate plating solution containing at least one of the following components (a) and (b) (Al). It is said that it is formed by roughening plating.

(a) At least one selected from oxyethylene surfactants, sulfur compounds, and safranin dyes.

(bl　chloride ion.

[For production]

By using a copper sulfate plating solution containing at least component (a) of the above components (a) and (bl), the precipitation of roughened plating is improved, and fine circuit grooves and plating sandwiched between plating resists are improved. Roughening plating is also precipitated during resisting.In other words, the surface of the conductor circuit of a fine circuit pattern can be made into a roughened surface, and the center and sides of the surface of the conductor circuit can also be made into a roughened surface. Therefore, even if the conductor circuit has a fine pattern, the adhesive force with the insulating layer can be strengthened, or the adhesive force with the insulating layer can be maintained at the same level in both the center and the sides of the conductor circuit. can do.

〔Example〕

Next, a method for manufacturing a printed wiring board according to the present invention will be described in detail with reference to drawings showing examples thereof.

FIGS. 1(a) to 1(hl) schematically represent a first embodiment of the method for manufacturing a printed wiring board according to the present invention in the order of steps.

First, a metal thin film 2 to be a release layer is formed on the surface of a temporary substrate 1 whose surface is conductive at least (FIG. 1(a)).

As the temporary substrate 1, a conductive metal plate such as stainless steel or titanium is used, but an insulating substrate with a conductive layer formed on the surface may also be used. These conductive metal plates and layers are used as snow shovels when forming metal thin films, conductive circuits, etc. that will serve as release layers on temporary substrates by electroplating. If necessary, at least the surface of the temporary substrate 1 on which the conductor circuit is to be formed may be subjected to polishing, degreasing, acid treatment, etc. as appropriate. The release layer is formed, for example, by electroplating the temporary substrate 1 or by subjecting it to an anodic electrolysis treatment, a dichromic acid solution immersion treatment, or the like.

On the metal thin film 2, a negative pattern opposite to the conductor circuit to be formed is created by imaging the plating resist 3, that is, so that the metal thin film 2 is exposed in the reverse pattern of the conductor circuit to be formed. Metal thin film 2
covered with plating resist 3), and exposed metal thin film 2
A conductive circuit 4 is formed thereon by electroplating (FIG. 1(b)).

A roughening treatment was applied to the surface of the conductor circuit 4 (Fig. 1(C)
), the plating resist 3 is peeled off to expose the entire surface of the temporary substrate 1 on which the conductor circuit is formed (FIG. 1(d)) 6 and below.
A roughening process for forming at least a roughened surface of the conductor circuit 4 is referred to as a "first surface forming process." The primary surface forming treatment is performed by forming a roughened plating film (roughened surface) 5 on the surface of the conductive circuit 4 by, for example, electroplating. Then, the entire surface of the temporary substrate 1 on which the conductor circuit is formed is roughened (FIG. 1(e)). Below, temporary board 1
The surface roughening treatment performed on the entire conductor circuit forming surface is called "secondary phase surface treatment." In the second phase surface treatment, electroplating, etc. By this plating method, a finer roughened surface 6 as shown in FIG. 3(b) is formed.

The insulating layer material 7 is superimposed on the surface of the temporary substrate l on which the conductive circuit 4 is formed (FIG. 1 (fl)), and the conductive circuit 4 and the insulating layer 8 are integrated by a molding press (indicated by arrows A and B), etc. The surface metal thin film 2 and fine rough surface 6 are removed by etching or the like to obtain a printed wiring board 11 (FIG. 1(h)). This fine rough surface 6 is sufficiently removed by etching and does not cause problems such as poor insulation between adjacent conductor circuits 4.

FIG. 2 (al to (gl) schematically represent the second embodiment of the present invention in the order of steps. The process is carried out in the same manner as in the first embodiment above, except that:
Components that are the same as in Figure 1 are given the same numbers and symbols. After the conductor circuit is formed in the first assembling process, the plating resist 3 is stripped and removed by 1 tlt to expose the entire surface of the temporary substrate 1 on which the conductor circuit is formed (FIG. 2(C)). After that, the printed wiring board 10 is obtained in the same manner as in the first embodiment (see FIG. 2(di-(
e) - (r) = (g)) In the first and second embodiments above, the second phase surface treatment is also performed, so the adhesive force between the conductor circuit and the insulating layer is determined by the second phase surface treatment. It is larger than the one without surface treatment. That is, in the present invention, it is preferable to perform the secondary phase treatment rather than not performing it.

1st grading process (when not performing 2nd grading process)
Alternatively, the insulating layer may be formed after performing zinc plating or chromate treatment to improve the heat resistance and chemical resistance of adhesive strength following the secondary phase surface treatment. This is preferable because the adhesive strength between the conductor circuit and the insulating layer is less susceptible to deterioration due to heat and chemicals.

The adhesion between the conductor circuit and the insulating layer can be further improved by performing the secondary phasing treatment multiple times. When performing the secondary phase surface treatment multiple times, the surface roughening treatment may be performed using the same method or may be performed using different surface roughening treatments. In the latter case, for example, a method is adopted in which the entire surface of the temporary substrate on which the conductor circuit is formed is roughened by etching, and then the surface is further roughened by electroplating.

In this invention, the primary composition treatment includes the following components (a):
and (b), Ta) performed by roughening plating using a copper sulfate plating solution containing at least component (a).
At least one selected from oxyethylene surfactants, sulfur compounds, and safranin dyes.

(bl　chloride ion.

The concentration of component (a) in the copper sulfate plating solution is 0.001 to
Preferably it is 10mM. If it is less than 0.001mM, the effect of improving the precipitation in the fine circuit grooves sandwiched between the plating resists may not be obtained.

If it exceeds 10mM, there is a risk that uniform roughened peaks will not be formed.

The concentration of component (b) in the copper sulfate plating solution is 0 to 200p.
Preferably, it is pm. Although it is possible to form a rough pattern plating without adding component (b) at all, the component (Al) is consumed very quickly and needs to be refilled many times, and component (a) is decomposed and formed. Things accumulate,
It may be necessary to regenerate the plating solution (eg, activated carbon treatment) or to build a new bath. If it exceeds 200 ppm, there is a risk that uniform roughened peaks will not be formed.

As component (a), at least one selected from oxyethylene surfactants, sulfur compounds, and safranin dyes is used. Examples of sulfur compounds include thiourea and the like, =C=S.

Organic or inorganic compounds with groups such as -S, =S=O are used.

The component (bl) is a chloride ion (CI-), and is supplied, for example, by adding to the plating solution a compound that can generate chloride ions in the copper sulfate plating solution. Such compounds include, for example, , HCl2.NaCl1 are used.

In this invention, the secondary surface roughening treatment can be carried out by roughening plating, but can also be carried out by etching (for example,
Other methods such as dipping, spraying or electrolysis may also be used. When electricity is applied to the surface to be treated, the same effect as when performing electroplating can be obtained.

For example, the primary composition processing includes components (a) and (b).
), must contain at least component (a), Cu5O,
・511.0 from 10 to 250 g/j! , H*SO, at 10 to 250 g/It, and other components added as necessary.
This is carried out by depositing copper on a rough surface by electroplating to a degree of A/- while stirring with air. The more CuSO4.5H0 is used, the higher the current density becomes.
degree is preferred. The more H, SO4 there is, the better the uniform electrodeposition is, but if too much, Cu5O+ may not be able to be incorporated, so about 180 g/j' is appropriate.

The secondary surface forming treatment is performed using, for example, CuSO4.5H80.
10-250 g/It, HgSO4 10-25
0 g/l, if necessary, HNOI lθ~200
Prepare a plating solution with an appropriate composition containing chloride ions of about 20 ppm, g/l, and plating at a current density higher than that of the primary grating treatment, for example, about 5A#J, for about 3 minutes without stirring. This is done by electroplating to deposit copper as a finely roughened surface. The more Cu5Oa.5H80 is used, the higher the current density becomes. The more H1SO4, the better the uniform electrodeposition, but if it is too much, CuSO4 may not be able to be added, so about 100g/j' is appropriate.When tlNO* is added, a fine rough surface is formed. The range of conditions for plating becomes wider, making it easier to manage plating conditions.The more oNos there is, the more plating becomes possible at higher current densities, but since it is corrosive, the amount added must be adjusted in consideration of the work environment. It is preferable to set the concentration of chloride ions, and approximately 30 g/l is appropriate.The smaller the amount of chloride ions, the more plating becomes possible at a higher current density, and approximately 10 ppm is appropriate.
When stirring is performed during plating in the subsequent surface forming treatment, it is necessary to use a current density higher than the above-mentioned current density.

Industrially, it is appropriate to perform the secondary surface forming treatment in this manner.

When performing plating for the first or second surface forming treatment, the plating solution may be stirred, but the stirring method is not limited. For example, it is possible to use air agitation, or to circulate the plating solution inside and outside the plating tank and stir it outside the plating tank. When circulating the plating solution inside and outside the plating tank, arrange the inlet for the plating solution into the plating tank and the outlet for the plating solution from the plating tank so that the plating solution flows along the surface to be plated. Good too.

Further, the plating method is not limited to the above-mentioned method, and the method of supplying the plating solution to the plating solution for plating is not particularly limited. Examples of the insulating layer material 7 include prepreg made by impregnating a fibrous base material with resin; A resin film or sheet is used. Furthermore, it is not necessary to integrate the conductive circuit 4 and the insulating layer 8 by stacking the insulating layer materials 7 and pressing them together; for example, it is not necessary to integrate the conductive circuit 4 and the insulating layer 8 by overlapping the insulating layer materials 7 and pressing them. The resin is placed in the cavity and molded to form the insulating layer 8.
At the same time, the conductor circuit 4 and the insulating layer 8 may be integrated.

Note that this invention is not limited to the above embodiments.

For example, the conductor circuit need not be made entirely of the same material; the bonding portions may be made of different conductive materials. It is not necessary to remove the plating resist before integrating the conductive circuit and the insulating layer, and the plating resist may also be integrated with the insulating layer.

Although specific examples and comparative examples of the present invention are shown below, the present invention is not limited to the following specific examples.

Example 1 - A printed wiring board was made according to the first example described above (FIG. 1 (al to h)).

Using vinyl adhesive tape as masking tape,
Thickness of one side masked with the same masking tape: 1. Bright copper sulfate plating is applied to Oryu's stainless steel Fi (temporary board 1), and a 4.5p thick copper film (metal thin film 2) is applied to the unmasked side of the same stainless steel plate.
was formed. This bright copper sulfate plating was performed under the following conditions.

On the obtained copper film, use a dry film for plating (negative photocurable resist resin trademark Ordil AP938 for printed board plating manufactured by Tokyo Ohka Kogyo Co., Ltd.) (plating resist 3) to form a conductor. A negative pattern was formed so that the copper film was exposed by turning the circuit pattern upside down.

Furthermore, bright copper sulfate plating was performed, and a patterned plating circuit (conductor circuit 4) having a thickness of 30 μm was formed on the exposed copper film. This bright copper sulfate plating was performed under the following conditions.

Furthermore, primary copper sulfate roughening plating (primary phase surface treatment) was performed under the following conditions, and the surface of the pattern plating circuit was coated with a thickness of 8.
After forming the μ layer roughening plating film 5, the resist is removed with a 5M% sodium hydroxide aqueous solution to expose the entire surface of the stainless steel plate on which the pattern plating circuit is formed. Then, surface roughening plating (secondary surface roughening treatment) was performed using copper sulfate roughening plating to form a fine rough surface 6. This copper sulfate roughening plating was performed under the following conditions. ``FR-4 (NEMA) is applied to the entire surface with roughening plating
Standard) prepreg (made by impregnating a glass cloth base material with epoxy resin) (insulating layer material 7),
They were integrated by heating and pressure molding at a temperature of 170° C., a pressure of 30 kgf/cxl, and a time of 90 minutes. As a result, a laminate was formed on the stainless steel plate in which the conductive circuit was embedded in the substrate (insulating layer 8) via the copper film. After this laminate was peeled off from the stainless steel plate together with the copper coating, the copper coating on the surface was removed using a sodium persulfate etching solution to obtain a printed wiring board 11.

Example 2 A printed wiring board was obtained in the same manner as in Example 1 except that the secondary surface forming treatment was not performed.

Example 3 - A printed wiring board was made according to the second example (see Fig. 2 (illustration)).

In Example 1, instead of forming the patterned plating circuit by bright copper sulfate plating, it was performed by primary assembling treatment to form a patterned plating circuit (conductor circuit S) with a rough surface and a thickness of 38 μm. A printed wiring board 10 was obtained in the same manner as in Example 1 except for the above.

Example 4 A printed wiring board was obtained in the same manner as in Example 1, except that the conditions for the primary surface forming treatment were as follows.

(Agitation... - Air agitation conditions for boat fishing - Example 5 - Printed wiring was carried out in the same manner as in Example 1, except that the conditions for the first assembling process were as follows. Got the board.

Comparative Example 1 A printed wiring board was obtained in the same manner as in Example 1, except that the conditions for the primary surface forming treatment were as follows.

The masking on the back side of the conductor circuit forming surface of the temporary substrate was left as it was after transfer molding, and transfer molding could be repeated. In addition, when repeating transfer molding, it is preferable to re-polish the surface from which the conductor circuit has been peeled off. It is also preferable to polish the surface of the temporary substrate on which the conductor circuit is to be formed before starting the first transfer molding.

Regarding each printed wiring board obtained in Examples 1 to 5 and Comparative Example, fine patterns (circuit width 75n, interval between circuits 7
The adhesion strength of the conductor circuit (5n) was investigated. The measurement method is JI
The peel strength in the 90" direction was measured using a tensile testing machine in accordance with S standard C6481, and was converted to per 1 cm width. The unit is kgf/cn+. After the treatment was completed, the state of precipitation of the roughened plating on the fine pattern portion was observed using a microscope to determine whether the precipitation was successful (◯) or not (x).The results are shown in Table 1.

Table 1 As can be seen from Table 1, in the printed wiring boards obtained in each example, the adhesive strength of the finely patterned conductor circuit was large, and the deposition state was good. In the comparative examples, the adhesion force of the conductor circuit of the fine pattern was very small, and the deposition condition was also poor. It can be seen that the adhesive force is greater in Example 2 in which this is not done. Among component (a), Examples 1 and 3 using an ethylene glycol surfactant had better adhesive strength than Examples 4 and 5 using other components.

〔Effect of the invention〕

As described above, the method for manufacturing a printed wiring board according to the present invention, which utilizes a transfer method, can improve the precipitation of rough plating even at the edge of a fine pattern or plating resist. , a printed wiring board with improved adhesion between the finely patterned conductor circuit and the insulating layer can be obtained.

[Brief explanation of the drawing]

FIG. 1 (al to (hl) is a sectional view schematically showing the first embodiment of the method for manufacturing a printed wiring board of the present invention in the order of steps;
Figures (al to g) are cross-sectional views schematically showing the second embodiment of the method for manufacturing a printed wiring board of the present invention in the order of steps;
a) and (bl are enlarged cross-sectional views schematically showing the roughened plating film obtained by the primary surface forming treatment and the fine roughened surface formed by the secondary surface forming treatment, and FIGS. The river is a cross-sectional view schematically showing one conventional example in the order of steps.■...Temporary substrate 3...Plating resist 4...Conductor circuit 5...Roughened plating film 6...Fine Rough surface 8... Insulating layer 10.11... Printed wiring board Figure 2

Claims (1)

[Scope of Claims] 1. A conductive circuit having a roughened surface formed by a plating method using a plating resist on the surface of a temporary substrate whose surface is electrically conductive at least, and which is integrated with an insulating layer to produce the temporary substrate. In the method for manufacturing a printed wiring board in which the conductor circuit is transferred to the insulating layer by peeling off the conductor circuit, at least the roughened surface of the conductor circuit contains the following components (a) and (
Among b), a method for manufacturing a printed wiring board, characterized in that the printed wiring board is formed by roughening plating using a copper sulfate plating solution containing at least component (a). (a) At least one selected from oxyethylene surfactants, sulfur compounds, and safranin dyes. (b) Chloride ion.