Laser Soldering for Chip-on-Glass Mounting in Flat Panel Display Application

Authors: Lee J-H.; Kim W-Y.; Ahn D-H.; Lee Y-H.; Kim Y-S.

Source: Journal of Electronic Materials, Volume 30, Number 9, September 2001 , pp. 1255-1261(7)

Publisher: Springer

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Abstract:

Chip-on-glass (COG) mounting of area array electronic packages was attempted by heating the rear surface of a contact pad film deposited on a glass substrate. The pads consisted of an adhesion (i.e., Cr or Ti) and a top coating layer (i.e., Ni or Cu) was heated by an UV laser beam transmitted through the glass substrate. The laser energy absorbed on the pad raised the temperature of a solder ball which was in physical contact with the pad, forming a reflowed solder bump. The effects of the adhesion and top coating layer on the laser reflow soldering were studied by measuring the temperature profile of the ball during the laser heating process. The results were discussed based on the measurement of reflectivity of the adhesion layer. In addition, the microstructures of solder bumps and their mechanical properties were examined.

Keywords: CHIP-ON-GLASS COG; LASER HEATING; INTERFACIAL MICROSTRUCTURE; SHEAR STRENGTH; SOLDER BALLS

Document Type: Research article

Publication date: 2001-09-01