JPH0426402B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for inspecting a wiring pattern on a printed board, and more particularly to a method for inspecting a land pattern thereof.

Prior Art and Problems Recently, automatic inspection equipment has been developed that optically detects wiring patterns on printed circuit boards, converts them into electrical signals, and detects defects such as shorts and disconnections. could not be detected. Therefore, there is a need for the development of an inspection method that can detect defects in land patterns.

OBJECTS OF THE INVENTION Based on the above-mentioned conventional requirements, an object of the present invention is to provide a pattern inspection method capable of detecting defects in land patterns of printed circuit boards.

Structure of the Invention According to the present invention, this purpose is to optically detect the wiring pattern on the printed board, convert it into an electrical signal, binarize it, and store it in a memory circuit.
A device that reads and inspects the contents includes three parallel vertical length measurement sensors that are longer than the vertical length of the land pattern and within the horizontal length, and three parallel longitudinal length measurement sensors that are longer than the horizontal length of the land pattern , and three parallel horizontal length measurement sensors that fall within the range of the vertical length, and two diagonal length measurement sensors that are longer than the length of the land pattern in the diagonal direction and intersect with each other at the center. , and the length measurement sensor is constructed by arranging the longitudinal measurement sensor and the horizontal measurement sensor so that the center of each center measurement sensor coincides with the intersection of the diagonal measurement sensor. A pattern (land pattern) larger than the lead wire is detected using the length measurement sensor and diagonal length measurement sensor located at the center of the length measurement sensor and the horizontal direction measurement sensor, and then from the center of the length measurement sensor located at the center of the vertical direction. Detect the center of the land pattern by making sure that the lengths to the top and bottom ends of the land are approximately equal, and the lengths from the center of the horizontal center length measurement sensor to the left and right ends of the land are approximately equal. Then, the size of the land pattern is measured by each of the three length measuring sensors in the vertical direction and the horizontal direction, and when the values are not within a normal range, it is determined that the land pattern is defective. This is achieved by providing a pattern inspection method that

Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram for explaining a length measurement sensor used in the pattern inspection method according to the present invention. This length measurement sensor has three sensors LL', YY', and RR' in the vertical direction, three sensors UU', XX', and DD' in the horizontal direction, and three sensors FF' and FF' in the diagonal direction.
It is composed of a total of eight length measurement sensors, two of which are GG'. However, this length measurement sensor does not directly view the pattern on the printed board optically, but rather electrically processes the data stored in the memory circuit after viewing the pattern optically.

Next, the method of the present invention using such a length measurement sensor will be explained.

First, the following three conditions are set as an inspection logic for determining land defects. The measurement positions of the lands are shown in Figure 2.

Conditions (X+X'>l) ∧(Y+Y'>l) ∧(F+F'>l) ∧(G+G'>l) However, X+X' and Y+Y' are respectively the X direction and the The sum of the lengths in the ′ direction,
Alternatively, it is the sum of the lengths in the Y direction and Y' direction from the midpoint of the length measurement sensor YY', and l is the upper limit value of the lead thickness.

Conditions (M>X-X')∧(M>X'-X) ∧(M>Y-Y')∧(M>Y'-Y) where M is the center margin condition (U+U'<land lower limit) ∨ (X+X'<land lower limit)∨(X+X'>land upper limit) ∨(D+D'<land lower limit)∨(D+D'>land upper limit) ∨(L+L'<land lower limit)∨(L+L'>land upper limit) ∨(Y+Y '<Land lower limit) ∨(Y+Y'>Land upper limit) ∨(R+R'<Land lower limit)∨(R+R'>Land upper limit) A pattern larger than a normal lead wire is detected under the following conditions. The center of the land is detected according to the following conditions. Length measurements in the X and Y directions are performed under the following conditions, and if these are not within the normal range, it is determined that there is a defect. In other words, defect = ∧∧.

However, since the lead wire is pulled out in the U direction, this upper limit check is not performed.

FIG. 3 is a diagram for explaining the circuit configuration for realizing the test logic of this embodiment, in which a is a circuit diagram and b is an explanatory diagram of circuit symbols. In Figure a, circuit 1 surrounded by chain lines corresponds to the conditions, circuit 2 corresponds to the conditions, and circuit 3 corresponds to the conditions. This circuit consists of these three circuits 1, 2, and 3, and an AND circuit 4 that ANDs the signals from these circuits. If there is a defect in the inspected land, a defect signal is sent from the last AND circuit. It is becoming more and more like this.

Next, another embodiment of the present invention will be described.

This example uses the length measurement sensor (first
(see figure). The inspection logic consists of the following conditions.

Condition (X+X'>l) ∧(Y+Y'>l) ∧(F+F'>l) ∧(G+G'>l) Condition {(X+X'<Land lower limit)∧(X,X'≠OVF)} ∨{( Y+Y′<Land lower limit)∧(Y, Y′≠
OVF)} However, OVF is an overflow condition {(X+X'>land upper limit)∧(U+U'>land upper limit)} ∨{(X+X'>land upper limit)∧(D+D'>land upper limit)} Condition (Y+Y'>land upper limit) ) Defect=∧(∨∨) This embodiment uses the above conditions and first detects a pattern larger than a normal lead wire according to the conditions. Next, depending on the conditions, if the land is smaller in the X direction or the Y direction than a normal land, it is determined to be a defect. However, when the sensor overflows (all patterns), the measured length value will be smaller than the actual value, so inspection is prohibited. Next, depending on the conditions, when the length measurement value of two or more sensors in the X direction is larger than the normal land,
Defective. The reason why there are two or more wires is because the lead wires are drawn out. Next, depending on the conditions, if the Y direction is larger than a normal land, it is determined to be a defect.

From the above, it is larger than the normal lead wire, and
direction or Y direction is smaller than normal land,
Or, if two or more of the sensors in the X direction or the land in the Y direction is larger than a normal land, it is determined to be defective. That is, ∧ (∨∨).

FIG. 4 is a diagram for explaining the circuit configuration for realizing the test logic of this embodiment. In the figure, circuit symbols are the same as those in the previous embodiment. This circuit is
The part 10 to 13 surrounded by the chain line and the part 10 to 13
An OR circuit 14 whose input is the output of the circuit of
Input the output of the OR circuit and the output of circuit 10
It is composed of an AND circuit 15 and a circuit 10.
corresponds to the above conditions, circuit 11 corresponds to the above conditions, circuit 12 corresponds to the above conditions, and circuit 13 corresponds to the above conditions, and when the inspected land has a defect, a defect signal is sent from the AND circuit 15. Ru. In the circuit 11, OV is set to "0" when there is an overflow, and set to "1" when there is no overflow.

Effects of the Invention As explained above in detail, the pattern inspection method of the present invention has a total of 8 patterns, 3 each in the vertical and horizontal directions, and 2 in the diagonal direction.
By configuring a book length measuring sensor and inspecting a land pattern using a combination of the measured length values, the present invention has a great effect in that it becomes possible to inspect lands that could not be inspected conventionally.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the length measurement sensor used in the pattern inspection method of the present invention, Fig. 2 is a diagram showing the length measurement method of a land pattern, and Fig. 3 is a diagram illustrating the inspection logic of the pattern inspection method of the present invention. FIG. 4 is a diagram for explaining the circuit configuration for realizing the test logic of another embodiment of the present invention. In the drawings, 1, 2, and 3 are circuits corresponding to the test logic conditions, respectively, 4 is an AND circuit, and 10, 11, 12, and 13 are circuits corresponding to the test logic conditions of other embodiments, respectively.
4 represents an OR circuit, and 15 represents an AND circuit.

Claims (1)

[Claims] 1. In a device that optically detects the wiring pattern on a printed board, converts it into an electrical signal, converts it into a binary value, stores it in a memory circuit, and then reads and inspects the contents, the wiring pattern is longer than the vertical length of the land pattern. , and three parallel longitudinal length measuring sensors that fall within the horizontal length range, and three parallel horizontal length measuring sensors that are longer than the horizontal length of the land pattern and fall within the vertical length range. A long sensor and two sensors that are longer than the length of the land pattern in the diagonal direction and that intersect at the center of each other.
A book diagonal length measurement sensor is provided, and the length measurement sensor is arranged so that the center of each center length measurement sensor of the vertical length measurement sensor and the horizontal length measurement sensor coincides with the intersection of the diagonal length measurement sensors. The sensor is configured to first detect a pattern (land pattern) larger than the lead wire using the central length measurement sensor and diagonal length measurement sensor of the vertical length measurement sensor and the horizontal length measurement sensor, and then detect a pattern (land pattern) larger than the lead wire. The lengths from the center of the center length measurement sensor to the top and bottom edges of the land should be approximately equal, and the lengths from the center of the center length measurement sensor in the horizontal direction to the left and right ends of the land should be approximately equal. The center of the land pattern is detected, and the size of the land pattern is then measured using the three longitudinal and horizontal length measurement sensors, and if these values are not within the normal range, it is determined to be a defect. A pattern inspection method characterized by determining that .