JPH08242058A - Inspection method for printed wiring board - Google Patents

Abstract

PURPOSE: To improve the efficiency of inspection, in the inspection method for a printed wiring board for detecting the positional accuracy to the circuit pattern of the outline processing line made for cutting off one sheet of printed wiring board into a plurality of sheets. CONSTITUTION: A test pattern 20 is printed on an outline processing line 10, and in the case of having cut off the outline processing line, the test pattern 20 is divided into two test patterns 21 and 22. Through holes 21a and 21b and 22a and 22b are made, respectively, at the ends of these test patterns 21 and 22. In such a constitution of test pattern 10, to detect the positional accuracy of the outline processing line 10, the outline processing line 10 is cut off to begin with, and the test pattern 20 is divided into the patterns 21 and 22. And, the resistance between each through hole 21a and 22b and between 22a and 22b of the patterns 21 and 22 are measured, and based on this measured value, the quantity of dislocation from the design position of the outline processing line 10 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a printed wiring board, and more particularly to a print for detecting the positional accuracy of a contour processing line formed for cutting one printed wiring board into a plurality of pieces with respect to a circuit pattern. A method for inspecting a wiring board.

[0002]

2. Description of the Related Art In the manufacture of printed wiring boards, a plurality of circuit patterns are often printed on one printed wiring board. The printed wiring board on which a plurality of circuit patterns are printed as described above requires an operation called outer shape processing for separating each circuit pattern. In this case, as a means for efficiently separating the wiring pattern, there is a method in which an outline processing line for cutting is provided in advance on the line to be separated. The contour processing line may be a groove-shaped one, a long hole-shaped one, or the like.

However, if the positional accuracy of the contour processing line is poor, the position with respect to the actually formed circuit pattern may differ from the design position. Then, the separated circuit pattern and the end face of the substrate are misaligned. When this happens, you can mount parts on the circuit pattern,
There is a possibility that a defect will occur when it is mounted on the device. Therefore, conventionally, several points on the contour processing line are sampled, a probe is applied to each point to detect the coordinate position, and the position accuracy is detected.

[0004]

However, the work of sampling a large number of points on one printed wiring board is troublesome and the work efficiency is poor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inspection method and a test pattern for a printed wiring board, which improves the work efficiency of the inspection of the positional accuracy of the contour processing line. To do.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to detecting the positional accuracy of a contour processing line formed to separate one printed wiring board into a plurality of boards with respect to a circuit pattern. In a method for inspecting a printed wiring board, a test pattern is formed on the outer shape processing line at a design position centered on the outer shape processing line, and after the outer shape processing line is cut off, the test cut together with the outer shape processing line is performed. The resistance value of each pattern piece of the pattern is measured, the measured resistance values are compared, and the degree of deviation between the actual position of the contour processing line with respect to the circuit pattern and the design position is detected. A featured printed wiring board inspection method is provided.

[0007]

[Operation] A test pattern is formed on the outer shape processing line at a design position centered on the outer shape processing line, and after the outer shape processing line is separated, the resistance value of each pattern piece of the test pattern separated together with the outer shape processing line is measured. To do. Then, the measured resistance values are compared to detect the degree of deviation between the actual position and the design position of the contour processing line with respect to the circuit pattern.

With this, it is possible to easily detect the positional accuracy of the contour processing line.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view showing a schematic configuration of the printed wiring board of this embodiment. The printed wiring board 1 is a multilayer printed wiring board, and for example, three circuit patterns 2, 3, 4 are formed on the printed wiring board 1. These circuit patterns 2, 3 and 4 may have the same wiring pattern or different wiring patterns. The printed wiring board 1 is preliminarily formed with a contour processing line 10 for separating the circuit patterns 2, 3 and 4 after forming them. The outer shape processing line 10 may have a groove shape or a long hole shape.

Test patterns 20 and 30 are printed on a part of the contour processing line 10. The test patterns 20 and 30 are printed simultaneously with the circuit patterns 2, 3 and 4. Further, the numbers and positions of the test patterns 20 and 30 are appropriately changed.

FIG. 1 is a plan view showing a specific structure of the test pattern 20. The outer shape processing line 10 has a width of about several mm, and the test pattern 20 is formed on the outer shape processing line 10.
Is printed. As a result, when the contour processing line 10 is separated, the test pattern 20 is divided into two test patterns 21 and 22. Through holes 2 are formed at the ends of these test patterns 21 and 22, respectively.
1a, 21b, 22a, 22b are formed.

In order to detect the positional accuracy of the contour processing line 10 in the test pattern 20 having such a structure,
First, the contour processing line 10 is cut off, and the test pattern 20
Is divided into patterns 21 and 22. And pattern 2
1, 22 between the through holes 21a and 21b, 22a,
The resistance between 22b is measured, and the amount of deviation of the contour processing line 10 from the design position is detected based on the measured value.

FIG. 3 is a diagram showing parameters required to detect the amount of deviation of the contour processing line 10 from the design position. First, the length of the pattern 21 in the outer shape processing line 10 direction is L1 and its width is W1, and the length of one pattern 22 in the outer shape processing line 10 direction is L2 and its width is W2. Further, it is assumed that the deviation amount of the contour processing line 10 from the design position 10a is δ, the thickness of the test pattern 20 is T, and the volume resistivity of the conductor used in the pattern is ρ.

By using these parameters, between the through holes 21a and 21b of the patterns 21 and 22, and 22
Resistance values R1 and R2 between a and 22b are expressed by the following equations (1) and (2), respectively.

R1 = ρL1 / T (W1 + δ) (1) R2 = ρL2 / T (W1-δ) (2) When the shift amount δ is calculated by the equations (1) and (2), = (R2L1W2-R1L2W1) / (R1L2 + R2L1) (3), which is the design value L1, L2, W1, W known in advance.
2, and the shift amount δ can be easily calculated from the measured resistance values R1 and R2.

The resistance values R1 and R2 can be easily and accurately measured in milliohms by using a 4-terminal resistance measuring device such as a Kelvin clip. Further, here, the lengths L1 and L2 and the width W of the pattern are
If 1 and W2 are designed to be equal in advance, the formula (3) can be simplified as the following formula (4).

Δ = W (R2-R1) / (R1 + R2) (4) Here, W = W1 = W2.

As described above, in this embodiment, the outer shape machining line 1 is used.
The test pattern 20 is formed on 0, and the resistances at both ends of the two patterns 21 and 22 formed by separation are measured,
Since the deviation amount δ of the contour processing line 10 from the design position is detected based on the measured value, the positional accuracy of the contour processing line 10 can be easily detected.

In this embodiment, the printed wiring board 1 is a multilayer printed wiring board, and the through holes 21a, 21b, 22a, 22 are formed at the respective resistance measurement points of the patterns 21, 22.
Although b is formed, in the case of a single-layer printed wiring board, a pad may be formed instead of the through hole.

[0020]

As described above, according to the present invention, a test pattern is formed on a contour processing line at a design position centered on the contour processing line, and after the contour processing line is separated, it is separated together with the contour processing line. Measure the resistance value of each pattern piece of the test pattern, compare the measured resistance value,
Since the degree of deviation between the actual position of the contour processing line with respect to the circuit pattern and the design position is detected, it is not necessary to detect the coordinate positions of multiple points on the contour processing line, and the contour processing line can be easily The position accuracy of can be detected.

[Brief description of drawings]

FIG. 1 is a plan view showing a specific configuration of a test pattern.

FIG. 2 is a plan view showing a schematic configuration of a printed wiring board of this embodiment.

FIG. 3 is a diagram showing parameters necessary for detecting a deviation amount of a contour processing line from a design position.

[Explanation of symbols]

 1 Printed wiring board 2, 3, 4 Circuit pattern 10 External processing line 20, 30 Test pattern 21, 22 pattern (piece) 21a, 21b, 22a, 22b Through hole

Claims (7)

[Claims] 1. A method for inspecting a printed wiring board for detecting the positional accuracy of a contour processing line formed to separate one printed wiring board into a plurality of pieces with respect to a circuit pattern, wherein the contour is provided on the contour processing line. A test pattern is formed at a design position where the processing line is the center, and after cutting the outer shape processing line, the resistance value of each pattern piece of the test pattern cut off together with the outer shape processing line is measured, and the measured value is measured. The resistance value is compared to detect the degree of deviation between the actual position of the contour processing line with respect to the circuit pattern and the design position. 2. The degree of deviation is calculated based on the measured resistance value, the distance between resistance measurement points of the pattern pieces, the width, and the thickness. The method for inspecting a printed wiring board according to 1. 3. The method for inspecting a printed wiring board according to claim 1, wherein the distance, width, and thickness between the resistance measurement points of each pattern piece are designed to be the same for both pattern pieces. . 4. A through hole is formed at a measurement point of the resistance value of each pattern piece.
Inspection method of printed wiring board described. 5. A test pattern of a printed wiring board for detecting the positional accuracy of a contour processing line formed to separate one printed wiring board into a plurality of pieces with respect to a circuit pattern, wherein the contour is provided on the contour processing line. A printed wiring board having a test pattern formed at a design position centered on a processing line. 6. The print according to claim 5, wherein the distance, the width, and the thickness between the resistance measurement points of each pattern piece are designed so that both pattern pieces are the same. Wiring board. 7. The printed wiring board according to claim 5, wherein a through hole is formed at a measurement point of the resistance value of each pattern piece.