Transient Thermal Characterization of a Stacked Multichip Package

Abstract

This paper is a case study of the thermal behavior of a stacked multichip package (SMCP). The aim is to measure temperature responses when heat is dissipated on different dice and to characterize the behavior with a compact thermal model (CTM) that accurately models steady-state and transient responses with a simple thermal RC -network. The measured package consists of three stacked layers, where each layer has one thinned flip chip attached die on an aramid interposer. The package's thermal responses were measured with thermal test dice that contain heaters and temperature sensors. The package was modeled with a finite element method (FEM) and the simulated temperature responses showed reasonable agreement with measured data. The FE model was further used to provide reference thermal data under different boundary conditions for CTM synthesis. The obtained CTM models accurately the steady-state and transient behavior and can be used as simplified model of the measured SMCP for further thermal analysis.