SOLDER BAR FOR HIGH POWER FLIP CHIPS

摘要

A solder bar compatible with conventional flip chip technology fabrication methods for high power/high current applications includes first and second generally circular solder pads of diameter D formed upon a substrate and connected by a solder bar pad of width BW. The centers of the generally circular solder pads are spaced apart by distance BL (bar length). A mass of solder having volume VB is formed over the first and second generally circular solder pads and over the solder bar pad to form a dog-bone shaped solder bar. The solder bar reaches height H 1 above the centers of the first and second generally circular solder pads, and reaching height H 2 above the midpoint of the solder bar pad. The values for diameter D, bar length BL, bar width BW, and solder volume VB are selected in such manner that H 1 and H 2 are approximately equal. Conventional circular (as viewed from above) solder bumps can be formed upon the same substrate; in this case, heights H 1 and H 2 are made approximately equal to the height of the conventional solder bumps.