Finally, they are using copper for the die-to-board interconnect.
"?Previous Intel processor generations such as the ?Prescott? used conventional flip-chip technology with lead-tin (Pb-Sn) solder balls,? adds Dick James, senior technology advisor at Chipworks. ?For the Yonah and Presler, Intel has switched to a process that uses plated copper pillars to form the interconnection between die and board. This reduces the lead content over traditional flip-chip packaging even in the latest ?Pb-free? devices. This is the first processor seen by Chipworks to use this advanced flip-chip technique.?
Copper Pillar Bumping in flip-chip assembly offers higher connection density, better electrical and heat-dissipating performance, greater mechanical strength and potentially increased reliability."
http://www.chipworks.com/news/2006_65nmLackBalls.asp
"?Previous Intel processor generations such as the ?Prescott? used conventional flip-chip technology with lead-tin (Pb-Sn) solder balls,? adds Dick James, senior technology advisor at Chipworks. ?For the Yonah and Presler, Intel has switched to a process that uses plated copper pillars to form the interconnection between die and board. This reduces the lead content over traditional flip-chip packaging even in the latest ?Pb-free? devices. This is the first processor seen by Chipworks to use this advanced flip-chip technique.?
Copper Pillar Bumping in flip-chip assembly offers higher connection density, better electrical and heat-dissipating performance, greater mechanical strength and potentially increased reliability."
http://www.chipworks.com/news/2006_65nmLackBalls.asp
