JPS60203803A - Inspection of pattern - Google Patents

Abstract

PURPOSE:To enable detection of a defect in a land pattern by contituting length measuring sensors consisting of total eight pieces including three pieces in a vertical direction, three pieces in a horizontal direction and two pieces in a diagonal direction and inspecting the land pattern by the combination of the length values measured by such sensors. CONSTITUTION:This sensor is constituted of total eight pieces of measuring length sensors including three pieces LL', YY', RR' in a vertical direction, three pieces UU', XX', DD' in a horizontal direction and two pieces FF', GG' in a diagonal direction. A circuit 1 corresponding to the specific equation is formed by determining the upper limit value for the size of leads so that the pattern larger than normal lead wires can be detected. Circuits 2, 3 corresponding similarly to the other specific equation to detect the center of lands and another specific equation to measure the length in the directions X, Y are respectively formed and the outputs therefrom are inputted together with the output from the circuit 1 to an AND circuit 4, by which a defect signal is obtd.

Description

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

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.
No defect in the turn could be detected. Therefore, there is a need for the development of an inspection method that can detect defects in land gloss turns.

OBJECTS OF THE INVENTION In view of 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.

According to the present invention, the wiring pattern on a printed board is optically detected, the electrical signal is converted into a binary signal, the signal is stored in a memory circuit, and the contents are read out and inspected. In the equipment used, three in the vertical direction, three in the horizontal direction,
This is achieved by providing a mother turn inspection method characterized in that a total of eight length measurement sensors, two in diagonal directions, are configured and a land pattern is inspected by a combination of their length measurement values.

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, and UU' in the horizontal direction.
, XX', DD', diagonally: FF', G
It is composed of a total of eight length measurement sensors, two of which are G'. However, this length measurement sensor does not directly view the 74 turns of the printed board optically, but electrically processes data stored in a memory circuit.

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.

Condition ■ (X+X')L) △(Y+Y')L) △(F+F'>L) △(G+G'>L) However, x0x' and Y0Y' refer to the length measurement sensor X direction and X'
It is the sum of the lengths in the direction, or the lengths in the Y direction and the Y' direction, and L is the upper limit value of the lead thickness.

Condition■ (M)X-X')△(M'-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'') ■(D+D'(Land lower limit) → (D+D') land upper limit) ■ (L ten' (runt lower limit) ■ (L ten') land upper limit) (Y+Y'< land lower limit) V (Y ten Y'> land upper limit) V (R+R'< Uy 1r11)■(R+R')7
yYJ3M) Next, according to the condition (2), a pattern larger than the normal lead wire is detected. Next, the center of the land is detected according to the condition (■). Next, X according to the condition of ■.

The length in the Y direction is measured, and if the length is not within the normal range, it is determined that there is a defect. That is, the 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 condition (2), circuit 2 to condition (2), and circuit 3 to condition (2). This circuit consists of these three circuits 1, 2.
3 and an AND circuit 4 that takes the sum of the signals from these circuits.
If there is a defect in the inspected land, a defect signal is sent from the last MD circuit.

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

This example uses the length measurement sensor used in the previous example (see Figure 1).
Use. The inspection logic consists of the following conditions.

Condition (υ (X+X')L) △(Y+Y')L) △(F+F'>L) △(G+G'>L) Condition■ ((X1X'〈5y limit)△(X,X''+0
VF))V((Y+Y'(run)"lower limit)A(Y,Y
'(OVF)) However, OVF is under the overflow condition■ ((X+X'>H fear for run)△(U1U'>Run block))■(ac+X>Run order)△(D+D')Runt 1'') ) - 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 condition (■).

Next, according to condition (2), if the land is smaller in the X direction or the Y direction than the normal land, it is determined to be defective. However, when the sensor overflows (all patterns), the measured length value actually becomes υ smaller, so inspection is prohibited.

Next, according to condition (2), when the measured length values of two or more sensors in the X direction are larger than normal lands, it is determined to be defective. The reason why there are two or more wires is because the lead wires are drawn out. Next, according to condition (2), if the Y direction is larger than the normal land, it is determined to be defective.

From the above, if the land is larger than a normal lead wire and smaller than a normal land in the X direction or Y direction, or larger than a normal land in two or more sensors in the X direction or in the Y direction, 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 consists of 10 to 1 surrounded by chain lines.
3 and the outputs of the circuits 10 to 13 as inputs.
It is composed of an R circuit 14 and a frame circuit 15 which inputs the output of the OR circuit and the output of the circuit 10. The circuit 10 meets the above condition, the circuit 11 meets the above condition The circuit 13 corresponds to the condition (■) and the circuit (13) corresponds to the condition (■), respectively, and if there is a defect in the inspected land, the AND
A defect signal is sent out from the circuit 15. In the circuit 11, Ov is set to 0" when there is an overflow, and is set to '1' when there is no overflow.

Effects of the Invention As explained in detail above, the four-turn inspection method of the present invention comprises a total of eight length measurement sensors, three each in the vertical and horizontal directions, and two in the diagonal direction, and their length measurement values are By inspecting the land pattern using the combination K, it is possible to inspect lands that could not be inspected conventionally, which is a great effect.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the length measurement sensor used in the 4-turn inspection method of the present invention, Figure 2 is a diagram showing the length measurement method of 4-turns, and Figure 3 is a diagram showing the pattern inspection method of the present invention. FIG. 4 is a diagram for explaining a circuit configuration for realizing test logic according to another embodiment of the present invention. In the drawing, 1.2.3 are the inspection logic conditions, respectively.
, ■, the circuit corresponding to ■, 4 is the 0 circuit, 10.11,
12.13 #'i Conditions for inspection logic 1 of other embodiments■■■
■The circuit corresponding to each, 14 is an OR circuit, 15 is A
ND circuits are shown respectively. Patent applicant Fujitsu Ltd. Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Akiyuki Yamaguchi Figure 1 Figure 2 (Q) (b) (C) (d ) (e) (f)

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 out and inspects the contents. A mother turn inspection method characterized in that a total of eight length measurement sensors are constructed, three in the diagonal direction, and a land pattern is inspected based on a combination of their measurement values.