Effect of case temperature measurement errors on the junction-to-case thermal resistance of a ceramic PGA

The author describes an experimental investigation in which measurements of junction-to-case thermal resistance, theta /sub jc/, of a 132-pin cavity-down ceramic (PGA) pin grid array package are compared to finite element (FEM) calculations. The initial goal of this work was to validate FEM predictions of theta /sub jc/ with measurements in accordance with the established SEMI and MIL standards. A serious problem was discovered in measuring accurate case temperatures, resulting in poor agreement between measured and predicted theta /sub jc/. Detailed 3-D FEM simulations were used to analyze thermocouple measurement problems in the region between the case and cold plate. New methods were developed using fiber-optic thermometry and surface-junction thermocouples.<<ETX>>

[1]  J. L. Prince,et al.  Experimental thermal characterization of VLSI packages , 1988, Fourth Annual IEEE Semiconductor Thermal and Temperature Measurement Symposium.

[2]  V. B. Dutta.  Junction-to-case thermal resistance-still a myth? , 1988, Fourth Annual IEEE Semiconductor Thermal and Temperature Measurement Symposium.

[3]  B. S. Siegal,et al.  Factors affecting semiconductor device thermal resistance measurements , 1988, Fourth Annual IEEE Semiconductor Thermal and Temperature Measurement Symposium.