JPH10200234A - Printed wiring board with fine pattern and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fine pattern at fine pitches even on a thick metal foil, by etching utilizing a multiply formed etching resist. SOLUTION: A multiply formed etching resist is utilized for etching and it includes a first and second resists. The first etching resist to be formed on the top of a pattern 5 is a metallic resist 2 for films such as dry films or solder plating and second etching resist to be formed on the pattern bottom is an electrodeposited one. These resists are utilized for a plurality of times for etching. The first resist on the pattern top functions as a film for producing the second resist on the pattern bottom and hence the alignment of the second resist-producing film can be omitted as overhangs on the pattern 5 serve for side face screens at the pattern top.

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 fine-pattern printed wiring board for realizing a high-density pattern formation of a printed wiring board in response to the high density of the printed circuit board. The present invention also relates to the realization of a printed circuit board having a fine pattern that can be realized by using a conventional printed wiring board manufacturing technique, equipment, and materials.

[0002]

2. Description of the Related Art A conventional printed wiring board pattern 51 shown in FIG.
It was formed by etching with one type of etching resist 54.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the following problems of the above-mentioned conventional printed wiring board pattern. The pattern of a conventional printed wiring board is formed by etching copper foil bonded to an insulating substrate with one type of etching resist. Has a trapezoidal cross-section, and when a fine pattern is formed at a fine pitch, a disconnection occurs at the top and a short circuit occurs with the adjacent pattern at the bottom. As a countermeasure, a fine pattern is formed by reducing the thickness of the copper foil. However, reducing the thickness of the copper foil is often unsuitable for satisfying the electrical characteristics.

[0004]

According to the present invention, in order to solve the above problems, a fine pattern of a printed wiring board is formed by etching using an etching resist formed a plurality of times. By this means, since the metal foil is etched by dividing into a plurality of times without reducing the thickness of the metal foil, a fine pattern that enables a fine pattern to be formed at a fine pitch even if the thickness of the metal foil is large. Provide a printed wiring board.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, according to a first aspect of the present invention, as shown in FIG. 1, a fine pattern is formed by etching using an etching resist 1 in which a metal foil 4 such as copper is formed a plurality of times. 5 was formed. By this means, since the metal foil is divided into a plurality of times without being thinned and etched as if the metal foil was thinned, a fine pattern can be formed even if the metal foil is thick. An effect that enables formation at a pitch is obtained.

Next, in a second aspect of the present invention,
As shown in FIG. 2, the etching resist used for the plurality of etchings is a film-based or metal-based etching resist 2 for the first etching resist for forming the upper part of the pattern 5 and the second etching resist for forming the lower part of the pattern 5. Was used as an electrodeposition type etching resist 3. By this means, without reducing the thickness of the metal foil, the thickness of the metal foil was divided into a plurality of stages and etched using two types of etching resists, so that as if the thickness of the metal foil was reduced, In addition, the first etching resist forming the upper portion of the pattern 5 functions as a film for manufacturing the second etching resist forming the lower portion of the pattern 5 because the overhang portion on the pattern 5 also functions as a light shielding portion on the side surface of the upper portion of the pattern 5. As a result, it is possible to obtain the effect that the positioning of the film for manufacturing the second etching resist can be omitted and a fine pattern can be formed at a fine pitch with high precision.

[0007] In a third aspect of the present invention,
As shown in FIG. 3, a step P01 of forming a first film-based or metal-based etching resist 2 on the surface of the metal foil 4 and etching it to form the upper portion of the pattern 5 on the surface of the printed wiring board 6 firstly. An electrodeposition type etching resist 3 of a second etching resist is formed on the surface of the metal foil 4 below the pattern 5 and on the side surface of the pattern 5 formed primarily, and etched to form the pattern 5 on the surface of the printed wiring board. And a step P02 of completing the lower portion by secondary forming. By this means, the thickness of the metal foil is divided into a plurality of stages and etched by using two types of etching resists without reducing the thickness of the metal foil, so that the fineness is as if the thickness of the metal foil was reduced. It is possible to form a simple pattern at a fine pitch, and to obtain an effect that can be realized by a simple process using a conventional printed wiring board manufacturing technology, equipment and materials.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG.

Reference numerals used in the drawings of the present invention shown in FIGS. 1 to 3 are collectively described below. Reference numeral 1 denotes an etching resist of an etching-resistant film applied to a portion where the pattern 5 is formed. Reference numeral 2 denotes an etching resist formed of a photosensitive film or metal plating in the etching resist 1. Reference numeral 3 denotes an etching resist of the etching resist 1 to which an etching resistant film is attached by charging. Reference numeral 4 denotes a metal foil using copper or the like as a conductor for forming a pattern 5 to be adhered to one or both surfaces of the insulating substrate. Reference numeral 5 denotes a pattern formed by etching the metal foil 4. Reference numeral 6 denotes a printed wiring board having a pattern 5 formed on an insulating substrate.

FIG. 1 is a diagram showing the principle of the present invention. In FIG. 1, a fine pattern 5 is formed by etching a metal foil 4 of, for example, copper by using an etching resist 1 in two stages in half. This allows the metal foil to be divided into two stages in half without reducing the thickness of the metal foil and to be etched as if the thickness of the metal foil was reduced by half. Patterns can be formed at a fine pitch. Although the etching depth in each step is set to half of the thickness of the metal foil in this drawing, the number of steps and the etching depth in each step can be varied depending on the manufacturing capability including accuracy.

FIG. 2 is a diagram showing an embodiment of the present invention. In the same drawing, the etching resist used for the plurality of etchings is changed to a first etching resist for forming the upper part of the pattern 5 by a film-based etching resist 2 such as a dry film or a metal-based etching resist 2 such as solder plating. Was used as an electrodeposition etching resist 3. Because of this, the thickness of the metal foil was divided into multiple stages and etched using two types of etching resists without reducing the thickness of the metal foil, so as if the thickness of the metal foil was reduced, In addition, the first etching resist forming the upper portion of the pattern 5 functions as a film for manufacturing the second etching resist forming the lower portion of the pattern 5 because the overhang portion on the pattern 5 also functions as a light shielding portion on the side surface of the upper portion of the pattern 5. As a result, the alignment of the film for manufacturing the second etching resist can be omitted, and a fine pattern can be formed at a fine pitch with high accuracy.

FIG. 3 is a manufacturing process diagram of the present invention. In the figure, a first film-based or metal-based etching resist 2 is formed on the surface of a metal foil 4 by exposure and development using a film for manufacturing an etching resist (not shown) as shown in FIG. A step P01 in which the upper portion of the pattern 5 is primarily formed on the surface of the printed wiring board by etching as shown in FIG. 2B, and the surface of the metal foil 4 below the pattern 5 and the side surface of the pattern 5 which has been primarily formed. As shown in FIG. 3C, an electrodeposition type etching resist 3 of a second etching resist is formed by exposure and development without using a film for manufacturing an etching resist as shown in FIG. Then, the lower part of the pattern 5 is secondarily formed on the surface of the printed wiring board as shown in FIG. As a result, the thickness of the metal foil is divided into a plurality of stages and etched using two types of etching resists without reducing the thickness of the metal foil. In addition to making it possible to form a simple pattern at a fine pitch, the first etching resist can be formed using a conventional printed wiring board manufacturing technique, equipment and materials, as shown in FIG. The overhanging portion on the upper surface 5 also functions as a light shielding portion on the side surface of the upper portion of the pattern 5, and also functions as a film for manufacturing the second etching resist forming the lower portion of the pattern 5, thereby aligning the film for manufacturing the second etching resist. It is possible to realize a fine pattern at a fine pitch with high precision and a simple process.

In this embodiment, the formation of a fine pattern has been described mainly on the case of a single-sided printed wiring board. However, even in the case of a double-sided printed wiring board, the pattern of an outer layer or an inner layer in the case of a multilayer printed wiring board is described. However, similar effects can be obtained by the combination of the present invention.

[0014]

The effects of the present invention described above will be described in the order of claims.

The printed wiring board having a fine pattern having the structure described in claim 1 is formed by etching using an etching resist in which a metal foil is formed a plurality of times. This allows the metal foil to be etched multiple times without reducing the thickness of the metal foil, as if the metal foil were thinner. It can be formed at a pitch.

In the printed wiring board having a fine pattern having the configuration according to claim 2, the etching resist used for etching a plurality of times is a film-based or metal-based etching resist that forms the first etching resist for forming the upper part of the pattern. The second etching resist forming the lower part of the pattern was used as an electrodeposition etching resist.
This makes it possible to reduce the thickness of the metal foil without reducing the thickness.
Since the thickness of the metal foil is divided into a plurality of stages and etched using various kinds of etching resists, the upper portion of the pattern is formed as if the thickness of the metal foil was reduced, in addition to the effect described in claim 1. The first etching resist also functions as a film for manufacturing the second etching resist that forms the lower part of the pattern, omitting the alignment of the film for manufacturing the second etching resist, and forming a fine pattern with a fine pitch and high precision. Can be formed.

According to a third aspect of the present invention, there is provided a printed wiring board having a fine pattern, wherein a first film-based or metal-based etching resist is formed on the surface of a metal foil and etched to form a pattern on the surface of the printed wiring board. Forming the upper portion of the pattern, and forming an electrodeposition-based etching resist of a second etching resist on the surface of the metal foil below the pattern and on the side surface of the pattern formed first, and etching the surface of the printed wiring board. And forming the lower part of the pattern secondarily to complete the pattern. This allows
In addition to the effects described in the first or second aspect, the present invention can be realized by a simple process using a conventional printed wiring board manufacturing technique, equipment, and materials.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is an embodiment diagram of the present invention.

FIG. 3 is a manufacturing process diagram of the present invention.

FIG. 4 is an embodiment diagram of a conventional example.

[Explanation of symbols]

 1,2,3 Etching resist 4 Metal foil 5 Pattern 6 Printed wiring board

Claims (3)

[Claims] 1. A printed circuit board having a fine pattern, wherein a fine pattern (5) of the printed circuit board (6) is formed by etching using an etching resist (1) formed a plurality of times. 2. An etching resist (1) used for the plurality of times of etching includes a first etching resist forming an upper part of a pattern (5) and a film-based or metal-based etching resist (2) and a pattern (5). 2. The printed wiring board with a fine pattern according to claim 1, wherein the second etching resist forming the lower portion is formed of an electrodeposition etching resist. 3. A first film-based or metal-based etching resist (2) is formed on the surface of the metal foil (4) and etched to form an upper portion of the pattern (5) on the surface of the printed wiring board (6). A step of primary forming (P01), an electrodeposition type etching resist (3) of a second etching resist on the surface of the metal foil (4) below the pattern (5) and on the side of the pattern (5) formed primary. ), And forming a second portion on the surface of the printed wiring board by etching to form a lower portion of the pattern (5) and completing the same (P02).