Models for computer simulation of complete IC fabrication process

The structure of a complete process simulator for modelling IC technologies is described. Multiple-step sequences which include ion implantation, oxidation, diffusion, epitaxy, and etching can be simulated. Features of individual process models for each of the steps are described in detail. Special emphasis is given to extrinsic diffusion phenomena for arsenic and phosphorus including coupling to boron. The kinetics of oxidation including concentration dependence and interaction of oxide growth with impurity migration are considered as well as the segregation phenomena. The problem of segregation for moving boundary problems in general is reviewed. As example, a bipolar process development using both surface deposition and implanted-phosphorus emitters is presented. Experimental results show that profile shapes, junction depths, and integrated base doping are extremely sensitive to the emitter diffusion as predicted by simulation.