Solder-Filled Elastomeric Spacer
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
A solder-filled elastomeric spacer is described which permits soldering semiconductor chips to substrates having a thermal coefficient of expansion differing from that of the semiconductor material. In the figure, the elastomeric sheet, serving as a spacer, is designated as 1. It has a hole pattern resembling the solder pad pattern of chip 2 which is soldered to the solder pad pattern on substrate 3. The holes in elastomeric sheet 1 are filled with solder strings 4 accommodating mechanical tensions resulting from the different thermal coefficients of expansion of the semiconductor material and the substrate. The solder strings also allow slight changes in the footprint of the chip or the substrate for improved wirability. When chip 2 is soldered to substrate 3, the holes in the elastomeric spacer keep the solder in place.