Sam Ziqun Zhao

Automatic Generation and Validation of Compact Network Models for a Fine Pitch BGA Package

A methodology for automatically generating compact thermal network models of increasing complexity, for use in numerical simulations of general semiconductor integrated circuit (IC) packages is presented. The method is based on the multi-grid agglomeration of the underlying mesh used in the finite volume discretization of the energy conservation equation of the package. The method is applied to a 196-pin fine pitch ball grid array (FBGA) package. Various network topologies and the corresponding network conductances were automatically extracted for this package. These networks were then used in computational fluid dynamics (CFD) simulations for a range of boundary conditions corresponding to single-phase natural and forced convective cooling. Results show good agreement with the detailed package simulations.Copyright

Development of RC network compact models of IC packages using multigrid method

The need for compact models of Integrated circuits (IC) is a well-recognized problem in electronics cooling simulations of electronic systems. Simplified thermal models have been reported in the literature to simulate the transient thermal behavior of IC devices. Most of the simplification approaches require a pre-determined topology of a resistance-capacitance (RC) network. Multigrid technique allows for automatically constructing both the topology and characteristics of the reduced-order or compact models of devices (primarily IC packages) for use in system-level simulations. In this study, we report an approach where the topology and the nodal RC values of the network are automatically generated. The procedure is also applicable for complex IC sub-systems or systems like multi-chip modules, stacked die package, system-in-package, and CPU module, and hard drives. In the study report herein, the method is applied to three types of IC packages. The first package is a 196-pin fine pitch ball grid array (FBGA15/spl times/15/spl I.bar/196 L) package. The second package is a 480-pin plastic ball grid array (PBGA+HS37.5/spl times/37.5/spl I.bar/480 L/spl I.bar/extHS) package with drop-in heat spreader. An external heat sink is attached to the top surface of the package. The third package is an 8-pin small outline IC (SOIC/spl I.bar/480 L) package with a total power dissipation of 0.5 W. RC networks are created for these packages and then used in CFD simulations for different boundary conditions, corresponding to single phase natural and forced convective cooling. The simulation results are compared to the corresponding detailed package simulations.