Flip chip process development techniques using a modified laboratory aligner bonder

Abstract

Tool modifications are described which have been made to a laboratory aligner bonder to allow specific process development techniques to be performed and evaluated for solder bump flip chip applications. Techniques described include: optics modifications to allow flip chip alignment to both rough and smooth surfaces; use of chip placement loads to permit temporary chip tacking for subsequent fluxless chip joining; thermal chucks for the flip chip rework operations of hot chip removal, site dress, and rejoining; and flattening of chip solder bumps for solder reflow/balling evaluations. These process steps are described with examples taken from MCNC's Flip Chip Technology Center Applications Laboratory using a Research Devices-modified M8A Aligner Bonder. The key tool parameters are indicated as well as the modifications made to enable the specific flip chip process steps to be performed.