Packaging Technology for Microprocessor

摘要

We developed FC-BGA (Flip Chip BGA) package of 1206-pin count for SPARC64GP~(TM) processor. This MPU achieved 450MHz clock frequency with the new technology as 0.18 μ m transistor, Cu (copper) tracing of 6-layers. The die size is 15mm sq., arranged SnAg (tin-silver) bumps to 223.2 μ m grid array of 4032 bumps. The package size is 37.5mm sq. arranged eutectic solder balls to package of 1.00mm grid array. As the substrate, we selected LTCC (Low temperature co-fired ceramic) with Cu traces. The feature is higher CTE (Coefficient of Thermal Expansion), that is 11.5 ppm/°C (degreeC) to match PCB (Printed Circuit Board). The lid as a heat spreader is made of AlC (Aluminum Carbon composite) that has high thermal conductivity and low elastic modulus. And the encapsulation was used higher adhesive epoxy resin. This FC-BGA has excellent performances as follows. The characteristic impedance was matched to 42 ohm within the range of 15%. Further the package brought low thermal resistance below 10°C/W at still air without a fin. The reliability test results of this package were excellent. The result of second-level packaging reliability was also good.