Finite Element Analysis Of The Electromagnetic Radiation From A VLSI Package Heatsink

The finite element method is applied to study the electromagnetic radiation from a VLSI package heatsink. A heatsink fastened to the IC package can be effective in eliminating performance degrading thermal effects, however its presence will also alter the pattern of the electromagnetic radiation. This paper does not deal with any thermal considerations, but looks only at the influence of various heatsink configurations on the radiated electromagnetic field. The finite element algorithm solves the magnetic field distribution about an axisymmetric model of an integrated circuit mounted onto a heatsink. The configurations are simplified and an equivalent induced noise voltage source is used to excite the antenna consisting of the chip and the heatsink. A radiation boundary condition allows the mesh to be truncated close to the heatsink. Results presented show how the configurations can either reduce or increase the radiated emissions.