Characterization of low alpha emissivity system on electroplated solder bumps

Abstract

As attention to System Soft Error Rate (SSER) grows, better semiconductor design guidelines are being created. To protect sensitive transistor nodes from alpha particles emanating from trace amounts of natural occurring radioisotopes, improved shielding materials such as die coat barrier films are being used. In parallel, the demand for lower alpha emissivity materials is growing, such that semiconductor materials suppliers and packaging groups must certify their materials as being of a certain alpha emissive content. To this end, this alpha detection system continues to gain prominence, with detection capabilities down to 0.001 alpha count/cm/sup 2//hour and sample measurement sizes to 1000 square centimeters. This study outlines a method of characterization and determines capability of the continuous gas flow proportional counter.