JPH0732309B2 - Method of manufacturing imposition mounted printed circuit board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an imposition mounting printed board having imposition lands to which imposition components such as leads of an integrated circuit are connected.

[Conventional technology]

A conventional imposition mounting printed circuit board is disclosed, for example, in JP-A-61-115.
As described in Japanese Patent No. 2090, the main focus is on the appearance shape for thinning or the like, or the shape of the imposition land for preventing misalignment, a method for forming the imposition land, or No consideration was given to the thickness of the imposition land.

Regarding the conventional method of manufacturing an imposition mounting printed circuit board,
FIGS. 5A to 5C show sectional views of the forming process of the imposition land by the general subtractive method.

Further, FIGS. 6 to 9 are sectional views showing a process of forming imposition lands by an additive method using chemical copper plating. Hereinafter, a detailed description of each step will be given.

First, an example of the conventional subtractive method will be described. First, as shown in FIG. 2, a through hole 3 for inserting and connecting a component is provided at a predetermined position of the copper-clad laminate 1 on which the copper foil 2 is formed. Next, the copper-clad laminate 1 including the inner wall of the through hole 3
After providing the catalyst layer 9 for depositing the chemical copper plating on the entire surface of, the thin chemical copper plating (electrolytic copper plating) layer 4 is deposited on the entire surface provided with the catalyst layer 9 to a predetermined thickness, It becomes the state of the figure. Next, an etching resist layer 5 (usually using a photosensitive dry film) is formed on a predetermined portion where a circuit is to be formed, and the state shown in FIG. 4 is obtained. Then, the fifth
As shown in the figure, after the copper plating layer 4 and the copper foil 2 other than the predetermined circuit portion are removed by etching using the resist layer 5 as an etching mask, a permanent solder capable of withstanding soldering required in a subsequent step in a necessary portion. The resist layer 8 is applied and formed by a printing method or an exposure method to form the through hole conductor 10 and the imposition land 7.

That is, in this method, after forming the copper plating layer 4 on the entire surface of the copper-clad laminate 1 including the inner wall of the through hole 3, the resist layer 5 is formed.
Is used to simultaneously pattern the copper foil 2 and the copper plating layer 4.

Next, an example of the conventional additive method will be described.
First, as shown in FIG. 6, a through hole 3 is provided at a predetermined position of a copper clad laminate 1 on which a copper foil 2 is formed, and the entire surface of the copper clad laminate 1 including the inner wall of the through hole 3 is chemically plated with copper. A catalyst layer 9 for layer deposition is formed (up to this point, it is the same as the subtractive method). Then, an etching resist layer 5 (usually a photosensitive dry film) is formed on a predetermined circuit portion, and the state shown in FIG. 7 is obtained. Next, the copper foil 2 other than the predetermined circuit portion is removed by etching using the resist layer 5 as a mask, and then the resist layer 5 is removed, and subsequently, a necessary portion is a permanent solder resist capable of withstanding the chemical copper plating step and the soldering step. When the layer 8 is formed by coating by the printing method or the exposure method, the state shown in FIG. 8 is obtained. Next, a chemical copper plating layer 4 is deposited on the exposed portion as shown in FIG. 9 to form a through hole conductor 10 and an imposition land 7.

That is, in this method, after the catalyst layer 9 for depositing a copper plating layer is formed on the entire surface of the copper-clad laminate 1 including the inner wall of the through hole 3, the copper foil 2 is first formed using the resist layer 5. After patterning, the permanent solder resist layer 8 is formed on a predetermined portion, and then the chemical copper plating layer 4 is deposited on the portion where the catalyst layer 9 remains.

Next, an example of a conventional method in which plating is not deposited on the imposition land will be described. For example, as described in JP-B-55-43274 and JP-A-55-75288, as shown in FIG. 10 to FIG. 11 is attached, and after the plating step, the photosensitive film resist 11 on the conductor portion which exposes the surface is peeled and removed.

[Problems to be solved by the invention]

When the copper foil 2 and the chemical copper plating layer 4 are simultaneously removed by etching in order to form the imposition land 7 of the imposition mounting printed board as in the subtractive method described above,
Since the thickness of the chemical copper plating layer 4 formed by deposition varies, there is a problem that the shape of the formed imposition land 7 varies.

Further, when the chemical copper plating layer 4 is deposited after the copper foil 2 is patterned by etching as in the above-described additive method, the chemical copper plating layer 4 is also deposited on the side surface of the imposition land 7. When the gap size between the lands 7 becomes small and the imposition lands 7 are provided at a high density, a short circuit easily occurs between the lands 7 and it becomes impossible to cope with high density imposition mounting.

As described above, the above-described conventional technique does not consider variations in the manufacturing method, thickness, shape, and spacing of the imposition lands, or short circuits between lands due to high density. There was a problem in workability and quality.

Further, in order to prevent plating from being partially masked by the above-mentioned photosensitive film resist 11 to prevent plating from being deposited, the method of removing after the plating step uses a film resist,
There is a problem that the conformability of the unevenness is poor, and a gap 12 is formed between the conductor patterns, and the plating solution permeates into the gap 12 in the plating step and contaminates the imposition lands.

An object of the present invention is to improve workability and quality of imposition mounting work, and to manufacture an imposition land with high accuracy.

[Means for solving problems]

The above-mentioned object is achieved by forming the imposition lands of the imposition-mounting printed board with only the copper foil of the copper-clad laminate.

That is, the method for manufacturing an imposition-mounted printed board of the present invention is a substrate having a copper foil on the surface, and a plating layer deposition catalyst layer is formed on the surface of the substrate including the inner walls of through holes formed in the substrate. A step of forming an etching resist layer at a predetermined portion on the copper foil, a step of etching away the copper foil using the etching resist layer as a mask, and at least resisting a copper plating step on the copper foil. A step of covering with a mask layer to be obtained, a step of depositing a plating layer to a predetermined thickness on a predetermined area including at least the inner wall of the through hole, and a step of removing the mask layer on at least a part of the copper foil And a first mask layer covering a predetermined region of the mask layer excluding the through hole and the portion that needs to be exposed on the surface, and at least a part of the copper except the through hole. A second mask layer that covers the upper surface, the second mask layer is a resist layer formed by coating by a printing method or an exposure method, and in the step of removing the mask layer, only the second mask layer is formed. Is removed.

Further, the first mask layer is a permanent solder resist layer capable of withstanding the subsequent copper plating step and soldering step.

[Action]

There is variation in the thickness of the copper plating layer formed by deposition, and thus the shape of the imposition land formed varies. In addition, when copper plating is deposited after etching the copper foil, copper plating is also deposited on the side surfaces of the imposition lands, and the gap dimension between the imposition lands becomes small,
It becomes impossible to cope with high density. From this, by forming the imposition land only with the copper foil of the copper-clad laminate,
It is possible to prevent variations in the shape of the imposition lands due to variations in the thickness of the copper plating layer and reduction in the gap size between the imposition lands.

Further, in the present invention, since the resist layer formed by coating by a printing method or an exposure method is used as a means for masking at least a part of the copper foil except the through holes and removing it after the plating step, the unevenness followability Therefore, no gap is formed between the imprint pattern and the conductive pattern, and contamination of the imposition lands due to penetration of the plating solution does not occur.

〔Example〕

An embodiment of a method for manufacturing an imposition mounted printed board according to the present invention will be described with reference to process sectional views of FIGS.

First, as shown in FIG. 1 (A), a through hole 3 is provided at a predetermined position of a copper clad laminate 1 (or a multilayer printed board base material that has been laminated and pressed) on which a copper foil 2 is formed, and then, A catalyst layer 9 for depositing a chemical copper plating layer is formed on the entire surface of the copper-clad laminate 1 including the inner walls of the through holes 3. Next, an etching resist layer 5 is formed on a predetermined circuit portion using a photosensitive dry film, and the state shown in FIG. 1 (B) is obtained. Then
Using the resist layer 5 as a mask, unnecessary copper foil 2 other than the predetermined circuit portion is dissolved and removed by etching, and then the etching resist layer 5 is also removed to obtain the state of FIG. 1 (C). Next, a permanent solder resist layer 8 having a shape that exposes only a circuit portion requiring a copper plating layer and that can withstand chemical copper plating in a later step and can also withstand soldering in a later step is printed or printed. Application and formation is performed by the exposure method, and the state shown in FIG. Then, a solder resist layer 6'which is required to withstand only the chemical copper plating in the subsequent step is applied and formed only on the imposition land 7 by a printing method or an exposure method, or a masking tape 6'is attached. The state shown in FIG. 1 (E) is obtained. Then, as shown in FIG. 1 (F), a chemical copper plating layer 4 is deposited to a predetermined thickness only on the exposed through hole 3 and conductor circuit,
Then, the solder resist layer or the masking tape 6'on the imposition land 7 is removed, and the imposition mounting printed board having the imposition land 7 in a completed state is manufactured. Since the imposition land 7 of the imposition mounting printed board manufactured by this method is formed only by the copper foil 2 of the copper-clad laminate 1, the width of the imposition land 7 and the gap size between the imposition lands 7 In addition, the thickness of the imposition lands 7 varies little, and the gap between the lands 7 does not become narrow, so that good imposition workability and high quality can be secured.

〔The invention's effect〕

As described above, according to the method of the present invention, it is possible to suppress the variation in the size of each part of the imposition land, and thus it is possible to improve the imposition workability of imposition parts and also improve the imposition quality. .

[Brief description of drawings]

1 (A) to 1 (F) are process cross-sectional views showing an embodiment of a method for manufacturing an imposition mounted printed board of the present invention, and FIGS. 2 to 5 are steps of an example of a conventional manufacturing method. A sectional view is shown. 6 to 9 are process cross-sectional views of another example of the conventional manufacturing method, and FIGS. 10 to 12 are process cross-sectional views of yet another example of the conventional manufacturing method. DESCRIPTION OF SYMBOLS 1 ... Copper-clad laminated board (print board base material) 2 ... Copper foil of a copper-clad laminated board 3 ... Through hole 4 ... Copper plating layer 5 ... Etching resist layer 6 '... Masking resist layer or masking tape 7 ... Imposition land 8 … Permanent resist layer 9… Catalyst layer 10… Through-hole conductor

Claims (2)

[Claims] 1. A substrate having a copper foil on its surface, a step of forming a plating layer deposition catalyst layer on the surface of the substrate including the inner walls of through holes formed in the substrate, and a predetermined process on the copper foil. A step of forming an etching resist layer in a portion, a step of etching away the copper foil using the etching resist layer as a mask, a step of covering at least the copper foil with a mask layer capable of withstanding a copper plating step, at least the above A step of depositing a plating layer to a predetermined thickness on a predetermined region including the inner wall of the through hole, and a step of removing the mask layer on at least a part of the copper foil, and the mask layer is ,
It comprises a first mask layer covering a predetermined area excluding the through hole and a portion that needs to be exposed on the surface, and a second mask layer covering at least a part of the copper foil except the through hole. The second mask layer is composed of a resist layer applied and formed by a printing method or an exposure method, and in the step of removing the mask layer, only the second mask layer is removed. Manufacturing method of printed circuit board. 2. The imposition mounted printed circuit board according to claim 1, wherein the first mask layer is a permanent solder resist layer that can withstand the subsequent copper plating step and soldering step. Manufacturing method.