JPH04307701A - Printed wiring board, its intermediate body, and its manufacture - Google Patents

Abstract

PURPOSE:To provide a printed wiring board, which enhance the accuracy of the resistance value of a resistance element between printed interconnections formed of a thin-film resistance interconnection, and which restrain the resistance element from being broken and also to provide its intermediate body and its manufacturing method. CONSTITUTION:At a first intermediate body, a resin film 2 is formed on the selective region of a copper foil 1 and a resistance film 3 is formed on the copper foil 1 in which the resin film 2 is formed. At a second intermediate body, the resistance film 3 at the first intermediate body is pasted on an insulating substrate 4. At a printed wiring board, the copper foil 1 is removed from a region excluding a region corresponding to an interconnection 12 at the second intermediate body and the resistance film 3 is removed from a region corresponding to the resin film 2 and excluding the region corresponding to the interconnection 12. 31 in the figure is a resistance interconnection formed by etching the resistance film 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improved printed wiring boards, particularly printed wiring boards having thin film resistance wiring, intermediates therefor, and methods for manufacturing the same. More specifically, we will focus on a printed wiring board that can improve the accuracy of the resistance value of a resistance element between printed wirings formed using thin film resistance wiring and prevent damage to the resistance element, and its intermediate and its manufacture. Relating to improvements aimed at providing a method.

0002

2. Description of the Related Art The term "thin film resistance wiring" as used herein refers to wiring formed inside a printed wiring board using a thin film resistor having a thickness of 1 .mu.m or less.

A printed wiring board having thin film resistance wiring according to the prior art will be explained with reference to FIG.

FIG. 4(a) is a sectional view (part) of a printed wiring board, and FIG. 4(b) is a plan view (part) thereof.

In the figure, 4 is an insulating substrate of a printed wiring board (the material is, for example, a glass epoxy base material), and 12
is the wiring of the printed wiring board (the material is copper, for example), and 5
Reference numeral 1 denotes a resistance wiring (made of a nickel-chromium alloy, for example). This resistance wiring 51 also exists in the area corresponding to the above-mentioned wiring 12, but the resistance element between the wirings can be generally regarded as a resistance wiring portion corresponding to the distance l between the wirings.

Next, a method of manufacturing a printed wiring board having the above-mentioned thin film resistance wiring will be explained with reference to FIGS. 5 to 7.

First, a resistive film 5 of a nickel chromium alloy is formed on a copper foil 1 using, for example, a sputtering method (see FIG. 5).
a)). This resistive film 5 is closely attached to an insulating substrate 4 made of, for example, a glass epoxy base material, and is pasted by heating and pressurizing it (Fig. 5 (
b)). Next, using a photolithography method, the copper foil 1 and the resistive film 5 are removed from the area excluding the area corresponding to the wiring and the area corresponding to the resistive wiring (FIG. 6(c)).・See Figure 6(d)). FIG. 6(c) is a plan view, and FIG. 6(d) is a sectional view taken along the line AA in FIG. 6(c). In the figure, 11 is the remaining copper foil, and 51 is the remaining resistive film, that is, the resistive wiring. Next, using the lithography method again, the residual copper foil 11 is etched using the resist pattern 6 to form the wiring 12 (see FIG. 7(e)). Thereafter, the resist film 6 is dissolved and removed to produce a printed wiring board having the thin film resistance wiring shown in FIG. 4.

[0008]

[Problems to be Solved by the Invention] However, in the printed wiring board having thin film resistance wiring according to the above-mentioned prior art, the resistance elements between the wirings are damaged due to side etching in the etching process using the photolithography method. There is a drawback that variations occur in the length (l in FIG. 4(a)) and width (w in FIG. 4(b)), and the accuracy of the resistance value of the resistor element is not fully satisfactory. Further, since the above-mentioned resistance wiring is extremely thin and the surface of the resistance element is exposed, there is a drawback that cracks are easily generated due to external impact or the like.

It is an object of the present invention to solve the above-mentioned drawbacks, and to provide a printed wiring board and its intermediate material, which improves the accuracy of the resistance value of the resistance element between wirings and prevents damage to the resistance element. An object of the present invention is to provide a method for manufacturing the same.

0010

[Means for Solving the Problems] The above object is achieved by the following intermediates for producing resistor wiring for printed wiring boards, intermediates for producing printed wiring boards, printed wiring boards, and the following respective manufacturing methods. .

[0011] The intermediate for manufacturing resistor wiring for printed wiring boards has a resin film (2) formed on selective areas of a copper foil (1),
Copper foil (1) on which this resin film (2) is selectively formed
This is an intermediate for manufacturing a resistance wiring for a printed wiring board, on which a resistance film (3) is formed.

[0012] This method for producing an intermediate for producing resistor wiring for a printed wiring board includes forming a resin film (2) on selective areas of a copper foil (1).
) and forming a resistive film (3) on a copper foil (1) on which this resin film (2) is selectively formed. It is.

[0013] The intermediate for manufacturing printed wiring boards is a printed wiring board manufacturing intermediate in which the resistive film (3) of the intermediate for manufacturing resistive wiring for printed wiring boards is adhered on an insulating substrate (4). It is an intermediate for use.

[0014] This method for manufacturing an intermediate for manufacturing printed wiring boards includes the step of pasting the resistive film (3) of the intermediate for manufacturing resistive wiring for printed wiring boards on an insulating substrate (4). 1 is a method for producing an intermediate for producing a printed wiring board.

In the printed wiring board, the copper foil (1) is removed from the area other than the area corresponding to the wiring (12) of the intermediate for manufacturing the printed wiring board, and the resin film (2) is removed from the area other than the area corresponding to the wiring (12). This is a printed wiring board in which the resistive film (3) is removed from an area other than the area corresponding to the wiring (12) and the area corresponding to the wiring (12).

This printed wiring board manufacturing method includes removing the copper foil (1) from the area of the printed wiring board manufacturing intermediate other than the area corresponding to the wiring (12), and removing the copper foil (1) from the area corresponding to the wiring (12). This method of manufacturing a printed wiring board includes the step of removing the resistive film (3) from a region excluding the region corresponding to 2) and the region corresponding to the wiring (12).

[0017]

[Function] In the printed wiring board and intermediate thereof according to the present invention, a resin film is formed in the area on the copper foil corresponding to the resistance element, and this resin film is formed by contact exposure using a mask or by printing. Since it is patterned, the dimensional accuracy is extremely high. Since the length and width of this resin film become the length and width of the resistor element, the length and width of the resistor element also have extremely high accuracy. Even if variations occur in the distance between the wirings due to side etching in the etching process, the length and width of the resistor element are determined by the length and width of the resin film, so they are not affected by the variations in the distance between the wirings. therefore,
The accuracy of the resistance value of the resistance element can be sufficiently improved.

Furthermore, since the resin film described above covers the surface of the resistor element, it protects the extremely thin resistor element from external impact and prevents damage to the resistor element.

[0019]

Embodiment First, a printed wiring board according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1(a) is a sectional view (part) of the printed wiring board, and FIG. 1(b) is a plan view (part) thereof.

In the figure, 2 is a resin film formed in a region corresponding to a resistor element, and 4 is an insulating substrate (made of glass epoxy base material, for example) of a printed wiring board. 1
2 is the wiring of the printed wiring board (the material is copper, for example),
Reference numeral 31 denotes a resistance wiring (made of, for example, a nickel chromium alloy or a nickel phosphorus compound). The length of the inter-wiring resistance element is approximately the same as the length S of the resin film.

Next, a method for manufacturing the above printed wiring board will be explained with reference to FIGS. 2 and 3.

First, one or both sides of the copper foil 1 is roughened,
A resin film 2 with a thickness of several μm is formed on the roughened copper foil 1 in a region corresponding to the resistance element by close exposure using a mask or by printing (see FIG. 1(a)). . Next, on the copper foil 1 on which the resin film 2 is formed, a resistive film 3 having a thickness of, for example, 800 Å (the material is made of, for example, a nickel chromium alloy or a nickel phosphorus compound) is coated using a sputtering method or an electroless plating method. ) to produce an intermediate for manufacturing resistor wiring for printed wiring boards (see FIG. 2(b)). Next, the surface of this intermediate on which the resistive film 3 is formed is placed on an insulating substrate (the material is, for example, a glass epoxy base material) 4.
Heat and pressurize (175℃, 15Kg/cm2,
60 minutes), and the above-mentioned intermediate is adhered to the insulating substrate 4 to produce an intermediate for producing a printed wiring board (see FIG. 3(c)). Next, after forming a resist film 6 with a pattern corresponding to the wiring pattern on the copper foil 1, etching is performed to form the wiring 1.
The copper foil 1 is removed from the area except for the area corresponding to 2, and the resistive film 3 is removed from the area except for the area corresponding to the resin film 2 and the area corresponding to the wiring 12 (see FIG. 3(d)). Thereafter, the resist film 6 is dissolved and removed to produce the printed wiring board shown in FIG.

[0024] When forming a large number of resin films on copper foil, the arrangement and shape of each individual resin film may be set according to the requirements each time. It may be formed on copper foil. In the latter case, a desired resistor element is formed by selecting an appropriate resin film from these resin films each time and removing only the copper foil on the selected resin film by etching.

[0025]

Effects of the Invention As explained above, in the intermediate for manufacturing resistor wiring for printed wiring boards according to the present invention, a resin film is formed on selective areas of a copper foil, and the resin film is formed on the copper foil on which the resin film is formed. The intermediate for producing a printed wiring board according to the present invention has a resistive film formed on the intermediate for producing a resistive wiring for a printed wiring board on an insulating substrate. In the printed wiring board according to the present invention, the copper foil is removed from the area other than the area corresponding to the wiring of the intermediate for manufacturing the printed wiring board, and the copper foil is removed from the area corresponding to the resin film and the area corresponding to the wiring. The resistive film is removed from a region other than the region, and the method for manufacturing an intermediate for manufacturing a resistive wiring for a printed wiring board according to the present invention includes forming a resin film on a selective region of a copper foil, The method for producing an intermediate for manufacturing a printed wiring board according to the present invention includes the step of forming a resistive film on the copper foil on which the resin film is formed. The method for manufacturing a printed wiring board according to the present invention includes the step of attaching the above-mentioned resistive film to the intermediate for manufacturing resistive wiring for a printed wiring board. The copper foil is removed from the area except for the area corresponding to the resin film, and the resistive film is removed from the area except for the area corresponding to the resin film and the wiring. The accuracy of the length and width of the resistive element is extremely high, and as a result, the accuracy of the resistance value of the resistive element is significantly improved compared to the conventional method. According to the results of experiments, the error in the resistance value of the resistance element was conventionally ±15%, but in the present invention it is ±5%. Furthermore, since the resistance element is covered and protected by the resin film, the resistance against external impact is improved. Furthermore, the number of etching steps in printed wiring board manufacturing is reduced from the conventional two to three steps to one, thereby improving work efficiency.

Therefore, the present invention provides a printed wiring board and its printed wiring board which can sufficiently improve the accuracy of the resistance value of the resistance element between wirings formed using thin film resistance wiring, and furthermore, can prevent damage to the resistance element. Intermediates and methods for producing the same can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view and a plan view of a printed wiring board having thin film resistance wiring according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a printed wiring board having thin film resistance wiring according to an embodiment of the present invention.

FIG. 3 is a manufacturing process diagram of a printed wiring board having thin film resistance wiring according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view and a plan view of a printed wiring board having thin film resistance wiring according to the prior art.

FIG. 5 is a manufacturing process diagram of a printed wiring board having thin film resistance wiring according to the prior art.

FIG. 6 is a manufacturing process diagram of a printed wiring board having thin film resistance wiring according to the prior art.

FIG. 7 is a manufacturing process diagram of a printed wiring board having thin film resistance wiring according to the prior art.

[Explanation of symbols]

1 Copper foil 12 Wiring 2 Resin film 3 Resistive film 31 Resistance wiring 4 Insulating substrate

Claims (6)

[Claims] [Claim 1] A resin film (2) is applied to selective areas of the copper foil (1).
) is formed, and a resistive film (3) is formed on a copper foil (1) on which the resin film (2) is selectively formed. body. [Claim 2] A resin film (2) is applied to selective areas of the copper foil (1).
) and forming a resistive film (3) on a copper foil (1) on which the resin film (2) is selectively formed. Method for producing intermediates. 3. An intermediate for manufacturing a printed wiring board, characterized in that the resistive film (3) of the intermediate according to claim 1 is adhered onto an insulating substrate (4). 4. A method for producing an intermediate for producing a printed wiring board, comprising the step of adhering the resistive film (3) of the intermediate according to claim 1 onto an insulating substrate (4). 5. The intermediate body for manufacturing a printed wiring board according to claim 3, wherein the copper foil (1) is removed from a region other than the region corresponding to the wiring (12), and the copper foil (1) corresponds to the resin film (2). A printed wiring board characterized in that the resistive film (3) is removed from an area except for the area and the area corresponding to the wiring (12). 6. The copper foil (1) is removed from the area excluding the area corresponding to the wiring (12) of the intermediate body for producing a printed wiring board according to claim 3, and the area corresponding to the resin film (2) is removed. A method for manufacturing a printed wiring board, comprising the step of removing the resistive film (3) from a region other than the region corresponding to the wiring (12).