Electrothermal effect analyses on palladium alloy cobra needles used in wafer testing.

• Main Authors: Chang, Zhi-Jie, 張智傑
• Other Authors: Chang, Dar-Yuan
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/91595720941056669641

碩士 === 中國文化大學 === 機械工程學系數位機電碩士班 === 100 === 　　In wafer testing, a palladium alloy cobra needle usually adopts as a testing medium for a vertical wafer probe card, which delivers the electric signals of the detected welding pad to the testing machine by directly contacting, to check the status of the electric circuit on the wafer chip. In wafer testing, each needle feeds a current of 250mA ~2A, and under a contact pressure of 2~5g/mil and a resistance of 1~2 ohm to finish the scrub motion on the welding pad. However, improper electric probing conditions would cause a needle softening or burning from electrothermal effect. 　　To understand the electrothermal effect of micro-probes in the testing process, this study implements two series experiments involving (1) micro-needle electric energy experiments, needle conductive experiments with different electric energy were first implemented. A digital camera was used to record the electrothermal process, and the color images of the experimental needle were captured in a constant time span based on image processing method. Afterward the image-electric energy model was successfully built. (2) micro-needle electrothermal experiments, the experiments were schemed based on the results of electric energy experiments. An infrared thermal imager and a digital camera were used to record the temperature raising process. The needle images and temperature distributions were obtained under a constant time span. Four image models, such as RGB, HSV, YIQ, and grey, were used to explore the correlation between needle image and temperature, and the image-temperature model of the examined micro-needle were established. 　　Results of this study provide an assessing standard for evaluating the electrothermal effect of palladium alloy cobra needle used in wafer testing industry based on digital image data.