3D Transient Thermal Solver using Non-conformal Domain Decomposition Approach

3D integration becomes promising to be able to continue the system integration trend due to short TSV interconnection used for stacked dies. This paper proposes an efficient transient thermal modeling method using non-conformal domain decomposition approach for 3D stacked ICs and systems. To alleviate the problem arising from the feature scale difference between stacked dies as well as package and PCB, the 3D system is divided into many subdomains. Each subdomain (die, package or PCB) can be meshed independently using different gridding based on its feature size and therefore the required meshing cells are greatly reduced compared to conventional method such as finite element or finite volume method. The heat flow continuity between subdomains is captured using the introduced interface basis functions. In addition, the proposed compact micro-fluidic model based on finite volume method is proved to be compatible with the finite element model for solid medium based on introduced forced convection boundary and energy conservation. The experimental results show the proposed method offers up to 5x unknown reduction and 91x speed-up compared to conventional finite element method.