JPS61173104A - Inspection of surface treatment of printed wiring board - Google Patents

Abstract

PURPOSE:To speed up the inspection of the treatment of a printed wiring board by irradiating light to the surface of the printed wiring board which is subjected to a surface-roughening treatment, measuring the angle at which the reflected light changes sharply, comparing the angle with the above-mentioned angle of a standard sample and discriminating the surface condition. CONSTITUTION:A light source 4 is disposed right above the surface 3 of the circuit pattern of the printed wiring board subjected to the surface-roughening treatment. The light is irradiated from the light source 4 to the surface 3 of the circuit pattern of the printed wiring board 1 and the quantity of the reflected light, i.e., the degree of the brightness on the surface is observed by a scope 5 while the angle with the surface 3 of the circuit pattern is changed. The point where the brightness changes considerably is found and the angle alpha of the scope in this stage is read by an angle reader 6. On the other hand, the angle alpha is measured with the standard sample of the known surface treatment depth by the similar method and the relation between the surface treatment depth and the reflection angle is preliminarily determined. The surface treatment depth corresponding to the above-mentioned angle alpha is read from a graph and the defectiveness and non-defectiveness of the sample are discriminated. The inspection of the treatment of the printed wiring board is thus speeded up.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a surface treatment inspection method for printed wiring boards.

[Technical background of the invention and its problems] Generally, a multilayer printed wiring board is made of a printed wiring board 1 on which a circuit pattern 7a is formed by etching and a material such as glass fiber epoxy resin, paper phenolic resin, etc., as shown in FIG. It is manufactured by alternately stacking several sets of insulating adhesive sheets 2 made of prepreg made of a composite material and integrally forming them by heating and pressing.

The metal conductor surface of the printed wiring board 1 is usually roughened to ensure good adhesion to the insulating adhesive sheet 2, but the degree of roughening has a large effect on the adhesive strength, so the surface condition of the printed wiring board is not suitable for adhesion. need to be inspected before.

Conventionally, the surface of the roughened circuit pattern 1a has been inspected by creating limit samples and having the worker compare the samples, but this method relies on the worker's color sense. The drawback was that it lacked universality. In addition, inspection has also been carried out by observing the surface condition using an electron microscope, but this method has the disadvantage of being too time consuming.

[Purpose of the Invention] The inventor of the present invention conducted studies to eliminate such conventional drawbacks, and found that by shining light on a roughened metal surface and observing the glossiness of the surface while changing the angle. They discovered that the gloss changes significantly at a certain angle, and that this angle has a correlation with the degree of surface roughening.

The present invention was made based on such knowledge, and an object of the present invention is to provide a method for easily inspecting the condition of a roughened printed wiring board surface in a short time.

[Summary of the Invention In other words, the method of the present invention shines light onto the surface of a printed wiring board that has been roughened, measures the angle at which the reflected light suddenly changes, and
By comparing this angle with the angle of a standard sample whose surface treatment depth is known and determining the surface condition, the surface condition of a roughened printed wiring board can be easily inspected in a short time. This made it possible to do so.

[Embodiments of the invention] Next, examples of the present invention will be described.

FIG. 1 is a side view for schematically explaining the method of the present invention.

As shown in the figure, a light source 4 is placed directly above the surface 3 of the circuit pattern of the printed wiring board 1 which has been roughened, and the light source 4 shines light onto the surface 3 of the circuit pattern of the printed wiring board 1. Observe the amount of reflected light, that is, the level of gloss on the surface, using the scope 5 while changing the angle α with respect to the surface 3 of the circuit pattern, and when you find a place where the gloss changes significantly, read the angle α of the scope at that time. Read with machine 6.

On the other hand, the angle α is measured in advance using a similar method for a standard sample whose surface treatment depth is known, and the relationship between the surface treatment depth and the reflection angle as shown in FIG. 2 is obtained.

The surface treatment depth corresponding to the angle α mentioned above is read from the graph of FIG. 2, and the quality of the sample is determined.

Note that the method of irradiating the printed wiring board is not limited to directly above the printed wiring board, but may be applied from an oblique direction.

In addition to visual inspection using a scope, optical sensors are also used to
The angle at which the amount of reflected light becomes large may be determined.

[Effects of the Invention] As explained above, according to the method of the present invention, processing inspection of a printed wiring board, which has conventionally been determined based on the operator's color sense, can be quickly and easily performed. Further, since the determination can be made by comparing numerical values, the accuracy is increased, the yield of the product is improved, and the workability can be improved.

[Brief explanation of drawings]

Fig. 1 is a side view for explaining the method of the present invention, Fig. 2 is a graph showing the relationship between surface treatment depth and reflection angle, and Fig. 3 is a diagram schematically showing the structure of a multilayer printed wiring board. . 1... Printed wiring board 2 - Insulating adhesive sheet 3... Surface of circuit pattern 4... Light source 5... Scope 6... ...Angle reader patent attorney Sa Suyama - 1r21 Figure 2

Claims (1)

[Claims] (1) Shine light onto the roughened printed wiring board surface, measure the angle at which the reflected light changes suddenly, and compare this angle with the angle of a standard sample with a known surface treatment depth determined in advance. 1. A surface treatment inspection method for a printed wiring board, the method comprising: determining the surface condition of a printed wiring board.