CMOS 이미지센서 소자의 자동화된 Visual 테스트

다국어 초록 (Multilingual Abstract)

With the expanded use of CMOS images sensors and the increased test quantity of the devices, this study performed the visual test (the naked eye based test) of CMOS image sensors in the type of automated test to find a faster and more accurate test method, and described the test results.
In this thesis, automated visual test was conducted with defect chips. To investigate whether they are detected, DC test, part of the automated test, was applied to conduct OPEN/SHORT test. In this way, whether to detect "no signal" of the visual test was examined. Because of the difference in output pattern between visual test and automated test, the part that was unable to be detected on the basis of image was applied to ISP Function test, and thus the defect chips with "Abnormal Screen" in the visual test were detected. In addition, through CMOS image detection test, the defect chips with image distortion in the visual test were detected. For test reliability, 25,419 chips were used in automated test and visual test. According to the test result, there was the throughput difference of 9 %. The cause for the throughput difference was investigated. It was found that a worker's poor skill for detection caused 3 %, and random defects caused by internal and external impurities led to the 6 % difference.
In conclusion, by conducting the visual test in the type of automated test, it was possible to increase the test quantity by five folds, and to improve accuracy in the way of detecting the 3 % chips that could have been undetected by a worker's poor skill.

목차 (Table of Contents)

• Ⅰ. 서 론 1
• 1.1 연구 배경 1
• Ⅱ. CMOS 이미지센서의 구성 4
• 2.1 CMOS 이미지센서의 구성 4
• 2.2 영상 촬상부 5
• 2.2.1 마이크로 렌즈 5
• 2.2.2 칼라 필터 6
• 2.3 아날로그 신호처리부 7
• 2.4 디지털 신호처리부 7
• 2.4.1 Color Interpolation 7
• 2.4.2 Color Correlation 7
• 2.4.3 Gamma Correlation 8
• 2.4.4 Color Space Conversion 8
• Ⅲ. CMOS 이미지센서의 특성 9
• 3.1 감도(Sensitivity) 9
• 3.2 동작 범위(Dynamic Range) 9
• 3.3 해상도(Resolution) 9
• 3.4 광학계(Optical Size) 11
• 3.5 화상 왜곡(Image Distortion) 13
• 3.5.1 블루밍(blooming) 13
• 3.5.2 백점(Dark Defect) 13
• 3.5.3 흑점(Black Defect) 13
• 3.5.4 Shading 14
• Ⅳ. 테스터를 이용한 효율적인 자동화 테스트 실험 과정 15
• 4.1 자동화 테스트를 위한 하드웨어 구성 15
• 4.2 자동화 테스트의 CMOS 이미지센서 동작 및 Capture 방식 17
• Ⅴ. 실험 결과 20
• 5.1 자동화 테스트의 DC 테스트 실험 결과 20
• 5.1.1 OPEN/SHORT 테스트 20
• 5.1.2 ISP Function 테스트 23
• 5.2 자동화 테스트의 이미지 검출 실험 결과 28
• 5.2.1 흑점 검출 테스트 29
• 5.2.2 백점 검출 테스트 32
• 5.2.3 수평 검출 테스트 35
• 5.2.4 수직 검출 테스트 37
• 5.3 테스트 시간 40
• 5.4 자동화 테스트와 Visual 테스트 비교 42
• 5.4.1 자동화 테스트와 Visual 테스트의 수율 비교 42
• 5.4.2 수율 차이 발생 원인 43
• Ⅵ. 결 론 47
• 참고문헌 또는 인용문헌 48
• 감사의 글 49