Introduction of BiCMOS into a production CMOS facility

A unique set of circumstances is required for the rapid introduction of a 1- mu m BiCMOS capability from R&D into a CMOS production facility. Not only was the lead time very short, but the wafer size and equipment sets were not compatible and the main thrust/experience of the personnel was different. The authors review the proposed novel solution, organizational details, technical approach, and accomplishments of this process transfer. The solution was to redefine the process using much of the existing production CMOS technology as a baseline and add additional features as required to generate a BiCMOS process. The criterion for transfer was not to reproduce certain sheet resistances, etch profiles, and diffusion cycles, but rather to achieve the same device electrical parameters. This decision allowed the designers to begin their work in earnest because they had a firm of model parameters for circuit simulations. Because much of the process was already well-established CMOS technology and the module development experiments resolved key BiCMOS unknowns, the first full flow process integration lots resulted in good yields of 64K CMOS and BiCMOS SRAMs.<
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