JPH05145215A - Formation of parts-positioning mark for printed wiring board - Google Patents

Abstract

PURPOSE:To provide the formation of a part-positioning mark for printed wiring board having good visibility and causing no deviation from a part-mounting land on the printed wiring board. CONSTITUTION:First, a wiring pattern 3, part-mounting land 7 and L-shaped part-positioning mark 4 modeling the visible outline of the corner part of an electronic part are formed on a plate substrate 2. Then, a solder resist layer 5 is formed on the whole surface of the substrate excepting the part-mounting land and part-positioning mark and solder plating is applied to the surface of the part-mounting land and part-positioning mark so that a printed wiring board is obtained. Subsequently, the corner part visible outline of a surface- mounting hybrid IC1 is put upon the inner side of the L-shaped part-positioning mark in the printed wiring board and positioning is conducted, and the land and the lead terminal electrode 6 of the hybrid IC are connected by reflow soldering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a component positioning mark used for positioning when mounting a surface mount type electronic component on a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board is manufactured and electronic components are manually mounted on the printed wiring board as follows. First, a wiring pattern and a component mounting land are formed on a plate-shaped substrate by etching.
Next, a solder resist layer is formed on the entire surface of the substrate except the component mounting lands to obtain a printed wiring board. In some cases, solder plating is applied to the component mounting lands in order to improve the wettability of the cream solder applied in the electronic component mounting process.

Next, in order to clarify the mounting position of the electronic component on the surface of the obtained printed wiring board, a frame-shaped line which is a part or the whole of the outline of the electronic component is applied by the screen printing method, Form component positioning marks. Next, the corresponding contour line of the electronic component is aligned with the component positioning mark for alignment, and the component mounting land on the wiring board and the lead terminal electrode of the electronic component are connected by reflow soldering.

[0004]

Conventionally, when manually mounting a prototype or a small-volume product, etc., a component positioning mark is formed on the printed wiring board, and it is used as a mark to electronically mount on the printed wiring board. Positioning of parts has been done. However, when the above-mentioned component positioning mark is formed by the screen printing method, a print deviation of about ± 0.2 mm may occur due to elongation and positional deviation of the silk screen mask. Therefore, if the component positioning mark is formed in a separate process after the wiring pattern and the component mounting land are formed as in the above-described conventional technique, a deviation occurs between the component mounting land and the component positioning mark. When mounting an electronic component having a narrow pitch between lead terminal electrodes such as a mounted hybrid IC, the lead terminal electrode may be connected to the wrong component mounting land.

Therefore, the present invention solves the above-mentioned problems of the prior art, has good visibility, and does not cause a deviation from the component mounting land on the printed wiring board. It is an object of the present invention to provide a method for forming the.

[0006]

Means for Solving the Problems As a result of earnest research for achieving the above object, the present inventors have found that the above problems can be solved by forming a component positioning mark at the same time as a component mounting land. Found and arrived at the present invention.

That is, according to the present invention, a wiring pattern, a component mounting land and a component positioning mark are simultaneously formed on a plate-shaped substrate, and a solder resist layer is formed on the entire substrate surface excluding the component mounting land and the component positioning mark. However, when the above-mentioned component mounting land is solder-plated in a later step, if necessary, the surface of the component positioning mark is also solder-plated. To provide a method of forming

[0008]

According to the method of the present invention, the component positioning mark, the component mounting land and the wiring pattern are all simultaneously formed on the surface of the plate-shaped substrate. Therefore, the relative positional relationship between the component positioning mark and the component mounting land becomes constant, and no deviation occurs between the two.

That is, when the wiring pattern and the component mounting land are formed by etching, since the component positioning marks are simultaneously formed using the same plate, the relative positional relationship between the component positioning mark and the component mounting land is always maintained. It will be constant and erroneous mounting will be prevented.

The surface of the component positioning mark formed by the method of the present invention is not covered with the solder resist and is exposed to the outside. Therefore, the component positioning mark has better visibility than the portion covered with the solder resist. Further, according to the method of the present invention, when the component mounting land is solder-plated, the component positioning mark is also solder-plated at the same time. Therefore, the component positioning mark formed on the printed wiring board has better visibility on the wiring board, and the positioning can be performed more easily.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the following examples.

[0012]

EXAMPLE A method of forming a component positioning mark for a printed wiring board according to the present invention and manual mounting of electronic components on the wiring board will be described below.

First, the wiring pattern 3, the component mounting land 7 and the component positioning mark 4 were simultaneously formed on the surface of the plate-shaped substrate 2 by the etching method. The component positioning mark 4 is formed in an L-shape that is a part of the outline of the electronic component to be mounted. Next, a solder resist layer 5 is formed on the entire surface of the substrate 2 excluding the component mounting lands 7 and the component positioning marks 4, and the surfaces of the component mounting lands 7 and the component positioning marks 4 are solder plated to form a printed wiring board. It was made.

Next, a surface mount hybrid IC was mounted on the above-prepared printed wiring board as follows. First,
L-shaped component positioning mark 4 on the printed wiring board
The corner outer shape line of the surface mount hybrid IC1 was aligned with the inner line of the position, and then the land 7 and the lead terminal electrode 6 of the hybrid IC 1 were connected by reflow soldering (FIG. 1).

The component positioning mark 4 is not limited to the above-mentioned L-shape, but may be formed in a concave shape which is the outer shape of the end of the electronic component as shown in FIG. 2 or as shown in FIG. It can be formed in a line along each side of the electronic component. Further, the positioning mark may be formed by using a part of the wiring pattern formed on the substrate.

Further, in this embodiment, the case where the component mounting land and the positioning mark are plated with solder is shown. However, depending on the printed wiring board, solder plating may not be applied. However, if the component positioning mark is not covered with the solder resist and is exposed to the outside as in the present invention without solder plating, the visibility is good.

[0017]

As a result of the development of the method of the present invention, the relative positional relationship between the component positioning mark and the component mounting land has not changed, so that the electronic component and the component positioning mark at the time of mounting the electronic component Alignment accuracy has improved remarkably and erroneous mounting of electronic parts has been prevented. Further, since the component positioning mark formed by the method of the present invention is excellent in visibility, it is possible to perform the alignment more easily. Furthermore, the positioning mark formed by the method of the present invention is particularly effective when a multi-terminal electronic component having a narrow pitch is manually mounted on a printed wiring board on which the mark is formed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a printed wiring board on which electronic components are mounted using component positioning marks formed by the method of the present invention, (a) is a perspective view, and (b) is a top view. Is.

FIG. 2 is a top view showing another example of a printed wiring board on which electronic components are mounted using the component positioning marks formed by the method of the present invention.

FIG. 3 is a top view showing still another example of a printed wiring board on which electronic components are mounted using component positioning marks formed by the method of the present invention.

[Explanation of symbols]

 1 ･ ･ ･ Surface mount hybrid IC 2 ･ ･ ･ Plate-like substrate 3 ･ ･ ･ Wiring pattern 4 ･ ･ ･ Parts positioning mark 5 ･ ･ ･ Solder resist layer 6 ･ ･ ･ Lead terminal electrode 7 ･ ･ ･ For component mounting land

Claims (1)

[Claims] 1. A wiring pattern, a component mounting land, and a component positioning mark are simultaneously formed on a plate-shaped substrate, and a solder resist layer is formed on the entire substrate surface excluding the component mounting land and the component positioning mark. Accordingly, when solder-plating the component mounting land in a later step,
A method for forming a component positioning mark for a printed wiring board, characterized in that the surface of the component positioning mark is also plated with solder.