The first pilot installation is scheduled for the end of 1999 at Siemens Components Pte. Via on Chip Pitch package has been qualified by NEC Corp. for use in flip-chip BGA packaging of ASICs. Coors Ceramics Co. will not relocate its Chattanooga, Tenn., facility. John Baliga, Associate Editor Low Alpha Lead Sources Are Emerging O ne concern for upcoming technology generations is soft upset generation caused by lead in flip-chip solder connections. This is due to alpha particle emission from the lead.
Alpha particles carry a positive charge and are highly energetic.
The lead used in flip-chip connections will have to be refined to reduce alpha emission to a very low level, much below the ambient cosmic level. This is because the lead will be in constant, close proximity to the chip. Also, if the lead is to be delivered in a powder form, its alpha emission must be extremely low. The radioactive decay chain from 210 Pb to 206 Pb ends with 210 Po decaying into 206 Pb and an alpha particle. The half-lives for each transition are shown.