Title :
Solder ball height measurement by projection method
Author :
Jingwen, Qin ; Yun, Chen ; FuLiang, Wang
Author_Institution :
State Key Lab. of High Performance & Complex Manuf., Central South Univ., Changsha, China
Abstract :
The height uniformity of solder ball is an important aspect of solder joint reliability for BGA package. A novel optical method for solder ball height inspection was proposed. A parallel beam was used to illuminate the solder ball, and the shadow of ball was used to measure its height. A machine vision system has been designed to realize this method. Solder ball image and shadow image are obtained by two time lightning and photograph. Digital image process algorithms are developed to evaluate the center and radius of solder balls from the solder ball image, and the projection length from the shadow image. With those information form images, the height of a solder ball and coplanarity is calculated. The experimental results obtained from this new method show good agreement with that obtained by SEM and Veeco.
Keywords :
automatic optical inspection; ball grid arrays; computer vision; height measurement; reliability; scanning electron microscopy; solders; BGA package; SEM; Veeco; coplanarity; digital image process algorithms; height uniformity; information form images; machine vision system; optical method; parallel beam; photograph; projection length; projection method; shadow image; solder ball height inspection; solder ball height measurement; solder ball image; solder joint reliability; two time lightning; Charge coupled devices; Fitting; Inspection; Machine vision; Measurement by laser beam; Robustness; Semiconductor device measurement; ball grid array; height measurement; image processing; machine vision; optical shadow;
Conference_Titel :
Electronic Measurement & Instruments (ICEMI), 2011 10th International Conference on
Conference_Location :
Chengdu
Print_ISBN :
978-1-4244-8158-3
DOI :
10.1109/ICEMI.2011.6037956
