EPOXY FLUX BRIDGES THE GAP TO LOW COST NO-CLEAN FLIP CHIP ASSEMBLY

摘要

A novel epoxy flux PK-001 is developed and tested for nocleanrnflip chip attachment processes with tin-lead eutecticrnsolder bumps. Results indicate that soldering and fluxrnresidue curing can be accomplished with a single reflowrnprocess. PK-001 provides adequate solder wetting andrnexcellent non-voiding behavior for flip chip applications.rnThe latter is attributable to its low volatility at above solderrnmelting temperature. The uniformity of joint coverage arearnenables a tight soldering quality control. This is particularlyrncrucial for high I/O count flip chip applications. Thernthermoset flux residue nature allows a good compatibilityrnwith underfills, particularly under high temperature and highrnhumidity conditions. Low ionics content, low corrosivity,rnand high SIR performance provide the essential remainingrnproperties required for no-clean applications.