Techniques in Extracting CSP Device from Underfilled PCB Module and Performing Solder Rework and Reballing for ATE Testing

Wednesday, November 8, 2017
Mr. Kah Chin Cheong , ON Semiconductor, South Portland, ME
Mr. Mark Lapierre , ON Semiconductor, South Portland, ME


The application of underfill materials for board level assembly has been increasing rapidly in semiconductor industry to enhance strength and reliability performance of semiconductor components in harsh environments. However, due to the intractability of the capillary underfill after curing, extracting a chip scale package (CSP) device from a printed circuit board (PCB) with a combination of mold compound and capillary underfill for ATE testing has become difficult and challenging. This poses a severe limitation to this technology regarding failure analysis. In order to address the challenge in extracting a CSP device from an underfilled PCB without inducing any mechanical damage, a series of sample preparation techniques has been introduced. This paper discusses the techniques in removing the mold compound and underfill material on PCB, performing soldering rework and reballing on fine pitch CSP in a relatively simple way which includes de-soldering process, residual solder balls remnant cleaning and reballing. The established process enables ATE testing, electrical testing and failure analysis to be performed on the CSP device. An electrical evaluation on the efficiency of the CSP device after a series of sample preparation processes will also be highlighted.