JPS6230519B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic component mounting device for applying a bonding medium to a wiring board and mounting the electronic component thereon. The following describes a typical example of a mounting device for electronic components of an integrated circuit.

A method of assembling integrated circuits is to print a wiring pattern using conductors, resistors, glass coating, etc. on a ceramic substrate, apply paste solder to the parts mounting area, place the parts on top of it, and fix it by applying heat. There is. FIG. 1 shows a cross-sectional view of a state in which components are mounted on a wiring board, and the wiring pattern 2, bonding medium 3, and electronic component 4 must be correctly aligned on the wiring board 1. Normally, alignment is performed based on the outline of the board 1, but since the wiring pattern 2 is printed on multiple sheets at once and then cut out by dividing, it is generally difficult to maintain high accuracy. I can't.

Therefore, conventionally, as shown in FIG. 2, a method has been adopted in which a reference pattern 5 is simultaneously printed as part of the wiring pattern 2 in the margin on the substrate 1, and this is used as a reference for alignment. Generally, if the surface is white, such as a ceramic substrate, a black material is selected as the reference pattern. In the figure, two reference patterns are provided so that two-dimensional coordinates on the substrate 1 can be uniquely determined by detecting two positions.

FIG. 3 shows an example of a device for automatically attaching electronic components by detecting the position of such a reference pattern. 6 is a position detecting means consisting of a television camera 7, a quantization section 8 and a pattern matching section 9; 13 is a control section 10 and a component supply section 11;
and a table 12. The substrate 1 on which the wiring pattern has been printed and the bonding medium has been applied is placed on a table 12 that moves two-dimensionally, and the wiring pattern on the surface of the substrate 1 is imaged by a television camera 7 installed above. The entire operation is controlled by the control unit 10,
First, in order to detect the position, the table 12 is moved so that one of the wiring patterns 5 in FIG. 2 is within the field of view of the television camera 7 in FIG. (The size of the field of view of the television camera 7 is determined as follows), and the position is detected by the pattern matching method described later. Next, the same thing is done for the other reference pattern 5 in FIG. The table 12 is moved so that the supply start command is issued.

The video signal from the television camera 7 is sent to a quantizer 8
As a result, the signal is processed so that the background is white and the reference pattern is black, and the pattern matching unit 9 compares the stored standard pattern showing characteristic parts of the reference pattern, such as corners, with the one on the screen. The degree of coincidence at each point is counted, and the coordinates of the point with the highest degree of coincidence are output.

Figure 4 schematically represents this operation.
In the field of view A of the television camera 7, a stored standard pattern S1 indicating a corner of the reference pattern 5,
With respect to S2, S3, and S4, P1, P2, P3, and P4 are detected as points with the highest degree of matching, respectively. The control unit 10 controls this operation and obtains the center coordinate P0 of the reference pattern 5 as the average value of P1, P2, P3, and P4. Such a position detection operation is performed for the two reference patterns 5, 5 shown in FIG. 2, and predetermined position values for setting components on other wiring patterns are calculated from the two center coordinates obtained. Normally, the control unit 10 requires calculation and control, and is composed of a microcomputer or the like.

The device configuration described above has made it possible to automatically attach parts, but since it does not have information about the bonding medium, even if there is a positional shift in the bonding medium, the position of the wiring pattern can be determined in the same way. Since the detection is performed and an operation command is issued to the parts supply section, defective products are produced and a large amount of material is wasted.

The purpose of this invention is to eliminate the above-mentioned drawbacks, by applying a bonding medium to the reference pattern as well, and detecting the positional deviation of the bonding medium at the same time as position detection. The system is designed to stop the supply of parts when a problem occurs, thereby preventing the production of defective products.

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

FIG. 5 shows an example of the reference pattern. In this case, the reference pattern 5 is formed together with the wiring pattern 2 in the margin of the wiring board 1 as in the past, but after that, when the bonding medium 3 is applied to the wiring pattern 2 according to the predetermined arrangement, the reference pattern 5 is simultaneously applied to the wiring pattern 2. The bonding medium is also applied to the center of the pattern 5.

If the coating is performed correctly, the reference pattern 5 will have a shape like 5a in FIG.
It has a shape like b. Therefore, if we examine the shape of this reference pattern 5, we can find that this reference pattern 5
At the same time as detecting the position, the size of the positional deviation of the bonding medium 3 with respect to the reference pattern 5 is known, and as a result, the size of the positional deviation of the bonding medium with respect to other wiring pattern components 2 is estimated, and the occurrence of bonding defects is predicted. can do.

Note that a portion of the many wiring patterns 2 may be used as the reference pattern 5.

FIG. 7 shows an example of a mounting device for electronic components 4 according to the present invention. The electronic component 4 in this case is an electronic component in an integrated circuit or a semiconductor chip. This device adds a detection means 15 consisting of an area counting section to the conventional device, and uses this function to detect displacement of the bonding medium at the same time as detecting the position.

The inspection means 15 sets area counting frames F1 and F2 as shown in FIG. Find the area. Now, F
1 as the size of the reference pattern and F2 as the size of the bonding medium, and the inspection means 15 counts the white areas in F1 and F2, that is, the area of the bonding medium. For a proper one with no misalignment like 5a in the figure, the areas in F1 and F2 are both the white area A (shaded area) of the bonding medium, as in FIG. 9a, Although the two values match, if there is coating misalignment as shown in 5b of Fig. 6, the area within F1 will change as shown in Fig. 9a, as shown in Fig. 9b. The total area is A, but since part or all of the bonding medium is outside the frame of F2, the area within F2 is B (shaded area), which is smaller than A, and the two values do not match. In this way, the area count values in F1 and F2 match when there is no positional shift of the bonding medium, and do not match when there is positional shift, resulting in a difference.

The amount of positional deviation of the bonding medium can be measured based on the difference in the area count values. If the amount of positional deviation is larger than a predetermined value, a stop signal is sent from the inspection means 15 to the control unit 10 of the component setting means 13. , the supply of electronic components from the component supply section 11 is stopped.

In addition, a coating unevenness detection circuit is added to the inspection means 15, and this circuit examines the signal level from the quantization section 8 in detail, and inspects the surface state of the bonding medium coated on the reference pattern 5 to detect coating unevenness. is detected, and when this coating unevenness is larger than a predetermined value, it is assumed that the coating unevenness of the bonding medium on other wiring patterns 2 is also large, and the above stop signal is output. Poor bonding of electronic components due to unevenness can also be prevented, and the generation of defective products can be more effectively prevented.

As described above, according to the present invention, it is possible to simultaneously detect the position of the wiring pattern and inspect the amount of deviation of the bonding medium from the wiring pattern, thereby preventing the occurrence of defective products and ensuring highly reliable installation work. A component mounting device is obtained.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing a wiring board on which electronic components are attached, Figure 2 is a plan view of the wiring board to explain the mounting work using a conventional mounting device, and Figure 3 is an example of a conventional mounting device. Block diagram shown, No. 4
The figure is a schematic diagram showing a pattern matching method for detecting the position of a reference pattern, FIG. FIG. 7 is a plan view showing a state of application to a reference pattern; FIG. 7 is a block diagram showing a mounting device according to an embodiment of the present invention; FIG.
FIG. 9 and FIG. 9 are schematic diagrams showing a method for measuring the amount of positional deviation of a bonding medium using the same apparatus. DESCRIPTION OF SYMBOLS 1... Wiring board, 2... Wiring pattern, 3... Bonding medium, 4... Electronic component, 5... Reference pattern, 6... Position detection means, 13... Part setting means, 15... Inspection means. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A wiring board that includes a reference pattern formed together with a wiring pattern, and a bonding medium on the wiring pattern and a bonding medium coated on the wiring pattern and the reference pattern in a predetermined arrangement. The electronic component mounting device mounts an electronic component to a portion coated with a bonding medium, the device comprising: a position detection means for detecting the position of the wiring pattern by detecting the position of a reference pattern coated with a bonding medium; a component setting means for setting an electronic component at a predetermined position on the wiring pattern coated with the bonding medium based on the position of the wiring pattern applied on the reference pattern, and a position of the bonding medium applied on the reference pattern with respect to the reference pattern. An electronic component mounting device comprising: a detection means for measuring the amount of positional deviation and outputting a stop signal to stop the operation of the component setting means when the amount of positional deviation is larger than a predetermined value. 2. The detecting means has a coating unevenness detection circuit that detects coating unevenness of the bonding medium applied on the reference pattern and outputs a stop signal when the coating unevenness is larger than a predetermined value. Mounting device for electronic parts.