Fuzzy thermal placement for multichip module applications
This paper presents an algorithm based on the fuzzy logic approach for the placement of the power dissipating chips on the multichip module substrate. In the conventional force-directed placement method. the forces are related to the number of connection among the modules. However, unlike the conventional force-directed placement method, the fuzzy approach is used to model the force interaction among the chips in our placement method. The force interaction and the distance between two chips are chosen as linguistic variables. The fuzzy placement analysis uses the Z and S membership functions to describe the repulsive and attractive forces among the modules. The proposed thermal force-directed placement method is then to relate the force equations to the power dissipation values of the individual bare chip. Details of implementation of our placement algorithm are provided. To verify the thermal placement prediction, the finite element analysis is carried out to map the thermal distribution of all the chips in the multichip module. Our fuzzy logic-based thermal placement method is applied to a multichip module for a case study. The finite element simulation results show our approach can obtain better thermal distribution than other traditional placement methods. (C) 2001 Elsevier Science B.V. All rights reserved.
fuzzy thermal placement multichip module finite element simulation