Peculiarities of measuring the alpha particle activity of flat samples of metals, alloys and powders using gas flow proportional counters specifically the model 1950 manufactured by 'Spectrum Sciences', USA

摘要

Naturally occurring radioactive emissions from solder (Pb/Sn or Pb-free) in semiconductor devices may result in memory device malfunctions and possible consequential product liability. These "soft errors" occur randomly but do not cause permanent physical damage to the memory cell. The principal product developed to reduce the probability of soft error malfunctions in memory devices is low alpha lead/tin alloys and low alpha lead-free alloys. As standards for determining alpha emitter emissions have not been adopted by the Semiconductor industry, proposed for discussion are actual testing methods and standards of measurement. Of interest, and the subject of this research is the description(s) of testing procedures and measurement techniques for accurate surface alpha emission counts from flat metal and alloy material, metal alloy powders, tin and lead oxide powders. These materials are used, principally, in solder paste, solder spheres, electroplating anodes, and plating chemistry. Discussion is focused on test equipment, sample preparation, alpha counting techniques and the accuracy of alpha emission measurements.