Realization of a High Precision Inspection System for the SOP Types of ICs

SOP형 IC의 고 정밀 외관검사 시스템 구현

  • Published : 2004.04.01

Abstract

Owing to small sizes and high density to the semiconductor It, it is difficult to discriminate the defects of ICs by human eyes. High precision inspection system with computer vision is essentially established for the manufacturing process due to the variety of defective parts. Especially it is difficult to implement the algorithm for the coplanarity of IC leads. Therefore in this paper, the inspection system which can detect the defects of the SOP types of ICs having 1cm${\times}$0.5cm of the chip size is implemented and evaluated it's performance. In order to optimally detect various items, some principles of geometry are theoretically presented , length measurement, pitch measurement, angle measurement, brightness of image and correcton of position. The interface circuit is designed for implementation of inspection system and connected the HANDLER. In the result, the system could detect two ICs' defects per second and confirmed the resolution of 20$\mu$m per pixel.

반도체 IC의 소형화와 고 밀도화에 따르는 소자의 외관적 불량을 육안으로 식별하는 것이 거의 불가능하며, 불량요소도 다양하여 고 정밀 비젼시스템의 도입이 필수적인 제조공정으로 자리매김 되고 있다. 특히 리드의 뜸 상태검사는 망상처리 알고리즘의 구현이 어려운 점이 있다. 따라서 본 논문에서는 칩의 면적이 1cm${\times}$0.5cm인 SOP형 IC의 불량을 검출하는 외관검사 시스템을 구현하고, 그 성능을 평가하고자 한다. 여러 가지 항목을 최적으로 검사하기 위하여 기하적 길이, 간격, 각도, 명도 및 위치보정 등을 이론적으로 전개하였고, 시스템 구성을 위해 인터페이스 회로를 설계하여 Handler와 결합하였다. 그 결과 초당 2개의 IC를 검사하고, 화소 당 20$\mu$m의 분해능을 가지는 계측 정밀도를 확인하였다.

Keywords

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