Heat dissipation measurement in flip-chip package using microfabricated temperature sensors on lid

Resistance Temperature Detectors (RTD) were intricately microfabricated onto a lid, presenting a pioneering approach to improve Junction-to-Case thermal resistance measurements on electronic packages. Traditionally, those involve intrusive lid drilling and cold plate grooving to accommodate the thermocouples integration as stated in JEDEC JESD51 standards. In lieu of this intrusive practice, microfabricated RTDs were adopted. A configuration of twelve RTDs was carefully distributed throughout the thermally active surface of an actual lid, offering a markedly less obtrusive measurement approach while enhancing temperature distribution and precision. Integration of these sensors to the lid surface, albeit inherently rough, was addressed through a spray coating planarization technique, effectively diminishing surface roughness without impinging on functionality. Results attest the functionality of RTDs across a temperature range from 20 to 105 degrees Celsius, exhibiting linear performance characteristics. The comprehensive analysis of sensor responses is detailed within this article.