Seiji Kashioka

A Transistor Wire-Bonding System Utilizing Multiple Local Pattern Matching Techniques

A fully automatic transistor wire-bonding system utilizing image-processing techniques is described. The system is composed of a minicomputer, image processors, and a maximum of 50 wire-bonding machines. Each machine has a TV camera installed to pick up, through a microscope, the image of transistor chips fed into the machine. In this system, one image processor services several machines in a group and analyzes the image signals in a time-sharing mode to determine the chip position at each machine. From the detected coordinates, an XY servomechanism in each machine is activated to bond and stretch wires between the electrodes on the chip and the outer leads. The recognition of electrode positions is accomplished by the multiple local pattern matching method in which redundancy is used in achieving a high recognition rate. An analysis of the system and basic features of the position recognition algorithm are also described. This method opens the possibility of economical automation of processes possible only by the human eye to date.

A position recognition algorithm for semiconductor alignment based on structural pattern matching

The authors propose a position recognition algorithm that can be used for future automated production of high-density semiconductor devices. It consists of a position detection method based on a pattern structure which is expressed as the distribution of characteristic local patterns, and an adaptive thresholding method based on an evaluation index which represents the binary state of characteristic local patterns. The validity and effectiveness of the algorithm are confirmed by experimentation with actual semiconductor chip patterns. High-speed processing of the algorithm is possible by using an image processor with simple matching hardware. >

A high-speed rotation method for binary images based on coordinate operation of run data

A method of image rotation based on digital image data has been developed. This paper assumes the binary digital data, and proposes a method which is different from the traditional one based on pixel data. This method can execute a high-speed rotation of the binary image based on coordinate data for the start and the end of the run

The application of image processing technology to industrial automation

Abstract Some typical applications of image processing technology in Japanese industry are introduced in this paper. A steady growth of application has been seen in a number of industrial fields over the past decade. The motivation for such applications has always been the demand for more efficient production systems and product quality improvement by eliminating human error. Results so far are promising, though the barriers presented by existing limitations to binary image processing remain to be overcome.

Automatic template selection technique for the local pattern matching method

One of the effective means of detecting the position of the object by image processing is by local pattern matching which uses only a part of the image as the template. It is required for the implementation of this method to select a unique part of the image to be used as the template. This paper discusses the automatic selection of a template. As the first step, the causes of mismatching are discussed, and the distribution of matching error between the template and local patterns extracted from the image is analyzed. Based on the result, an evaluation function is defined which represents the uniqueness in the selection of the template. Auxiliary evaluation functions are also defined for pre-selection and reduction of computation time. These evaluation functions are both for determining the appropriateness of the template, and can be implemented on a simple dedicated circuit with practical processing time.

Defect detection method for stamped patterns utilizing random access parallel matching technique

In the fabrication processor of electronic components, the outlook inspection has been performed primarily by visual observation. The automation of this process is presently considered important. This paper describes automatic defect detection considering the stamped pattern on the surface of the electronic parts on the integrated circuit, etc. The only clue to the information on the kind of electronics part is the characters and symbols stamped on its surface. In this sense, the stamped pattern is considered as a part of the part quality. Some defects of the stamped pattern are the disappearance, lack of a part, and dirt. The feature of these defects are discussed first. The fixed-point sampling is considered which detects the existence of the character pattern at the observation point. The method is modified so that the decision can be made at the observation point along the stroke. Furthermore, a character defect detection system is proposed which can shift the observation point in horizontal and vertical directions so that the system can cope with the variation of the position of the character. A dedicated image processing device was developed to perform the defect detection with high speed. The architecture and the operation of the system are described. The system is advantageous in that the high-speed operation is realized by the pipeline control for a series of processings, from the parallel read-out of the local patterns in the image memory to the matching operation. Finally, the configuration of the experimental system is described and the results are shown for the automatic outlook inspection for the stamped pattern of the actual electronic part, thereby indicating the usefulness of the proposed system.

Consideration on automatic defect detection algorithm for stamped patterns in electronic parts

Central Research Laboratory, Hitachi, Ltd., Kokubunji, Japan 185 n n n nOne of the most important problems in the quality inspection of printed characters, monitoring of printing devices, and evaluation of character recognition devices, is the automatic quality evaluation of the printed character for the character patterns stamped on the object surface or on a paper sheet. This paper considers the characters stamped on the surface of an electronic part such as transistor and integrated circuit, and reports on the result of comparison of defect detection methods for the automatic outlook inspection. First, properties of the stamped pattern, which is the object of inspection, are described, indicating the problems in detecting the defects such as lack, smudge and blur. Then three realizations of the defect detection are proposed: (1) a weighted matching is made with the reference pattern; (2) the reference pattern is divided spatially, and the matching is tried for the divided patterns; and (3) essential points are extracted from the core and background portions of the character, and a local pattern matching is tried. Finally, those defect detection methods are implemented on a computer, and an experiment was made for the actual stamped patterns on the transistor. The results for those methods are compared, and their effectiveness and the range of applications are indicated.

An automatic visual inspection method for a plastic surface based on image partitioning and gray‐level histograms

The outlook examination in fabrication of plastic products in the past has been performed mainly by visual inspection. The automation of the procedure is now considered to be important. This paper discusses a simple automatic detection method for defects on the surface of plastic electronic components such as integrated circuits. As the first step, optical properties of the defect such as flaw, pin-hole and bulge on the surface of the plastic components are discussed. This indicates problems in the detection of those defects. Then the illumination method using a planar light source is discussed to obtain a stable image against surface inclination. The procedure for practical detection of defects is developed in this paper as follows. First, to separate the image of the component surface from the background, the projection distribution of the gray-level histograms is constructed. The boundary of the component surface is extracted based on the histogram. Then the surface image is partitioned into subareas. The gray-level histogram is constructed for each partitioned subarea. Based on the maximum and the most-frequent value of the gray-level histogram, the existence or nonexistence of a defect in the subarea is determined. The experiment for the defect detection was performed using typical plastic components which are determined good or no-good. It is demonstrated that a correct defect detection can be performed for all kinds of components.

Local Pattern Matching Technique And Its Application To Semiconductor Production

A position recognition system composed of a television camera, a special purpose real-time image processor, and a general purpose microcomputer is developed. This system realizes a local pattern matching technique utilizing several local portions of an image as standard patterns. New resampling hardware enables the standard patterns to be matched against local patterns with a basic 8x8 or 12x12 window size and its multiples. Also, a high reliability recognition scheme with redundant matching sequence is programmed in the microcomputer. These features provide a cost effective device with wide application possibility. This technique is beeing successfully applied to automatic assembly systems for almost all types of semiconductor products.

Automatic position detection method for mounting ic parts on high-density printed circuit boards

In the automatic mounting system, which mounts electronic parts on a printed board, a problem is that the object printed circuit board is becoming of higher density and the parts have a fine lead structure. It is necessary that the positions of the part and the printed board should be detected with a high accuracy. It also became important to cope with the diversified parts with different shapes. This paper proposes a new practical method of automatic position detection to solve those problems. The proposed system is composed of the position detection process for the part and the position detection process for the printed board. In the process for position detection of parts, the positions of more than one lead are detected by the pattern matching, determining the similarity between partial images, and the position and the inclination of the part are calculated based on the result of matching. The viewing field is set so that only several leads are observed by the TV camera, and the object lens is moved to X and J directions so that the viewing field can be shifted to any desired position. In the position detection of the printed board, the positions of the two marks printed on the board are detected, and the position and the inclination of the printed board are calculated based on the mark positions. To evaluate the effectiveness of the proposed method, the position detection experiment was performed for the actual part and printed board, indicating that the position can be detected with a high accuracy.