Managing Kirkendall Microvoiding and Fracture Risks in High-Density Reflow
Manage Kirkendall voiding by capping plating bath sulfur impurities under 10 ppm and clamping reflow time above liquidus strictly between 45 and 60 seconds.
Glow Discharge Mass Spectrometry
Meaning
Direct solid analysis of high-purity materials with part-per-billion sensitivity is achieved through a plasma-based sputtering and ionization technique. Semiconductor manufacturers utilize glow discharge mass spectrometry to verify the elemental composition of sputter targets and silicon wafers. The method avoids the need for chemical dissolution, which eliminates the risk of sample contamination from liquid reagents.
It provides a comprehensive survey of trace and ultra-trace elements across almost the entire periodic table.
Analytical Method
Sputtering occurs when positive gas ions from a low-pressure plasma impact the surface of the solid sample. In glow discharge mass spectrometry, these dislodged neutral atoms are ionized in the plasma and then extracted into a mass spectrometer for separation. This dual action of sputtering and ionization ensures a steady signal that reflects the true bulk composition of the sample.
Material Purity
Electronic components require raw materials of extremely high purity to function reliably over long periods. Factories perform glow discharge mass spectrometry on high-purity copper and aluminum sputtering targets to detect trace metal contaminants. Even sub-ppm levels of mobile ions can cause electrical drift in finished microchips, making this analysis essential for quality assurance.
Sputtering Action
Continuous bombarding of the surface allows for depth-profiling of coatings. As the plasma gas removes material, the mass spectrometer tracks elemental changes to provide data on multilayer electronic structures.