JPH01160100A - Mounting - Google Patents

Abstract

PURPOSE:To enable mounting accuracy of ICs to be improved and an automation rate to be improved by providing a process for judging whether a pattern recognition is appropriate or not, by recognizing other IC patterns when the recognition was not performed appropriately, by performing compensation of pattern position of ICs when the recognition failed, and then mounting the ICs. CONSTITUTION:The center of gravity and slant of an IC which was placed on a stage 55 is measured and a robot 51 performs vacuum sucking of the position of center of gravity being based on this information. Since the position of IC enables video image to be taken through a transmission light, thus allowing for a stable recognition. Then, the robot 51 shifts a camera 53 to a position on a substrate for mounting IC, measures the position and slant of center of gravity of lead pattern on the substrate, and can accurately mount the IC on the lead pattern of substrate. If the recognition failed, the position of lead patterns 42 and 43 of the next IC mounting position is recognized and the position of the lead pattern 41 can be compensated relatively from the position of these two lead patterns. Being based on the compensation value, the IC picked up from the stage 55 can be mounted onto the printed-circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for mounting a plurality of semiconductor devices (hereinafter referred to as ICs) on a substrate.

[Conventional technology]

When mounting multiple semiconductor devices on a board, especially when mounting ICs such as flat packages with a large number of pins and narrow pin spacing on boards that are becoming increasingly dense, it is important to consider the position of patterns on the board. In order to correct variations, a reference pattern provided for each semiconductor device is recognized and mounted. FIGS. 4 and 5 are diagrams for explaining the conventional mounting method, and it is common to use pattern 1 or lead pattern 2 specially provided for position recognition as the reference pattern. In the case of pattern 1, the IC mounting position and inclination can be determined from the center of gravity positions of the two patterns, and in the case of lead pattern 2, the center of gravity 7 of each pattern provided in four directions 3.4.5.6 can be determined. .8.9.10 is determined, and the mounting position is determined as the intersection point 11 of straight lines 7-9 and 8-10. The slope can be determined by averaging the slopes of straight lines 7-8 and 9-10.

In this way, whether it is possible to recognize the pattern on the board and determine the mounting position, it is necessary to check for variations in lighting, variations in the surface condition of the pattern on each board (dirt, solder paste, flux, etc.). In many cases, it is not possible to capture a stable image depending on the condition of the adhesive (adhesion condition, resist coverage, etc.). Conventionally, such image variations have been dealt with by adjusting lighting, automatically adjusting the threshold level of binary images, and using software to compensate for multilevel images. This resulted in poor mounting accuracy and reduced yield. For example, in pattern 1, if the reference pattern is a perfect circle or the binary image shown in Figure 6 is partially missing due to the amount of solder coat, the center of gravity should be 20 or 21. This means that it will be judged as such.

[Problems to be Solved by the Invention] The present invention eliminates such drawbacks, and an object of the present invention is to provide a process for determining whether pattern recognition has been performed correctly, thereby preventing IC mounting due to recognition variations. In addition, when the recognition is not performed correctly, the pattern for other installed ICs is recognized, and the IC that could not be recognized based on the pattern position.
By correcting the pattern position and mounting the IC
This aims to improve mounting accuracy and automation rate.

[Means for solving problems]

A mounting method according to the present invention is a mounting method for mounting a plurality of semiconductor devices on a substrate, including: (1) recognizing the position of a pattern on the substrate provided for each semiconductor device;

(2) A step of determining whether the position of the pattern has been correctly recognized.

(3) A step of recognizing a pattern of another semiconductor device when the position of the pattern cannot be correctly recognized.

(4) A step of calculating and mounting a mounting position of a semiconductor device of a pattern that cannot be recognized from the pattern position of the semiconductor device on the side.

It is characterized by consisting of.

〔Example〕

FIG. 1 is a diagram showing a board 54 on which six flat package ICs 41 to 46 are mounted.
A pattern corresponding to the leads is formed, and the IC leads are mounted in accordance with this pattern and then bonded using a reflow process.

Figure 2 shows a mounter that automatically mounts an IC on a board 54.
51 is a Cartesian coordinate type robot, with a hand 5 including a rotation axis.
2 and a pattern recognition camera 53. 55 is I
At the position recognition stage C, the position of the IC supplied by a robot (not shown) is recognized. 54 is the first
This is the board shown in the figure.

The IC placed on the stage 55 measures the center of gravity position and inclination using the same principle as explained in FIG.
1 is based on this information, and the position of the center of gravity of the IC is vacuum-adsorbed. At this time, since the IC position can only be imaged using transmitted light, relatively stable recognition is possible.Fifth, the robot 51 moves the camera 53 to the IC mounting position on the board 54, and checks the lead pattern on the board. Measure the center of gravity position and inclination. Based on this result, it is possible to accurately mount the IC on the lead pattern of the board.

Here, since the lead pattern on the board is recognized by reflected light, it is difficult to recognize it stably depending on the surface condition of the board, especially the state of solder plating, the state of resist, the state of printing of solder paste, etc. Doing this stably is an important technique, and since it is different from the subject of this application, I will omit it here, but to check whether the recognition is done correctly or not, check the number of leads and check the lead pitch. This is possible. The mounter according to the present invention recognizes the positions of the lead patterns 42 and 43 at the next IC mounting position when recognition cannot be performed accurately. Lead pattern 4 is placed opposite to the position of these two lead patterns.
1 position can be corrected. Algorithms for position correction are well known. Stage 55 based on correction value
The IC picked up from the board is mounted on the board.

〔Effect of the invention〕

As described above, according to the present invention, when recognizing the position of a pattern on a board, even if there are variations in binary image capture due to the surface condition of the board, highly reliable mounting can be achieved by recognizing patterns with good conditions. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing patterns arranged on a substrate. FIG. 2 is a schematic diagram of a mounter mounted on an IC board, and FIG. 3 is a block diagram related to the mounting method of the present invention. FIG. 4 is a diagram showing a lead pattern in a conventional example. FIG. 5 is a diagram showing recognition marks when recognizing a lead pattern in a conventional example. FIG. 6 is a diagram showing a binary image of a reference mark. 1... Pattern 2... Lead pattern 3.4.
5.6... Pattern arrangement direction 7.8.9.10...
Center of gravity 11...Intersection 20.21...Image 41.42.43.44.43.46...Flat package IC51...
...Robot 52 ... Hand 53 ... Pattern recognition camera 54 ...
・・・・・・Substrate 55・・・・・・Position recognition stage and above Applicant Seiko Epson Corporation

Claims (1)

[Claims] In a mounting method for mounting a plurality of semiconductor devices on a substrate, the steps include: (1) recognizing the position of a pattern on the substrate provided for each semiconductor device; (2) A step of determining whether the position of the pattern has been correctly recognized. (3) A step of recognizing a pattern of another semiconductor device when the position of the pattern cannot be correctly recognized. (4) A step of calculating and mounting a mounting position of a semiconductor device of a pattern that cannot be recognized from the pattern position of the other semiconductor device. An implementation method characterized by comprising: