Paper
18 July 1988 Automatic Visual Inspection System For IC Bonding Wires
Hiroyuki Tsukahara, Masato Nakashima, Takefumi Inagaki
Author Affiliations +
Abstract
This paper discusses a high-contrast imaging capture system and a wire inspection algorithm for an automatic visual inspection system. On IC assembly lines, automated visual inspection is essential to maintain IC productivity and reliability. An automatic inspection system requires realtime inspection without defects overlooked. To overcome the difficulties of getting clear wire images and inspecting flexible object shapes, we developed a high-contrast imaging capture system and a wire inspection algorithm. The imaging capture system consists of a special camera, called a MegaCamera, by Fujitsu Ltd. , and structured lighting. The MegaCamera satisfied both the requirements of 10-micron-per-pixel inspection resolution and an image capture area of 20 mm square. The structured lighting optic enabled us to get bright wire images and to reduce background noise. The wire inspection algorithm is based on border following. The algorithm enabled us to inspect curved and straight wires and to detect defects including broken wires, too close wires, and incorrect wiring paths. When we installed the system on an actual IC assembly line, it took 28 s to inspect a 68-wire IC. The rate of correct detection is 99.7 percent for ICs and the rate of overlooked defects is 0 percent. These results indicate the system can inspect in real time without defects overlooked, which up to now have required visual inspection.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hiroyuki Tsukahara, Masato Nakashima, and Takefumi Inagaki "Automatic Visual Inspection System For IC Bonding Wires", Proc. SPIE 0939, Hybrid Image and Signal Processing, (18 July 1988); https://doi.org/10.1117/12.947058
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KEYWORDS
Inspection

Light sources and illumination

Imaging systems

Cameras

Algorithm development

Optical inspection

Signal processing

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