| Since the invention of the electrical transistor in 1947, nowadays it is unimaginable to think that modern society can function without electronic devices. The semiconductor industries enabled the increased use of new electronics in unlikely applications such as automotive. By understanding critical methods and its applications of industry standard semiconductor processes and failure analysis on various stages of the processes, one can use that knowledge to minimize process variation and improve production efficiency leading to final semiconductor product yield increases. Minimization of future failures of new semiconductor devices in the field is also achieved.
The polysilicon hole defects arise from a three-way interaction between the boron implant in polysilicon, subsequent thermal processing, and the BOE chemistry. During the annealing and activation thermal steps after implantation, boron with a high solubility solid limit will be strongly affected by the morphological lattice of polysilicon and will cause the grains to grow in size during redistribution, which rearranges the grain boundaries. Therefore, grain boundaries and lattices of polysilicon are physically impacted by the boron implant and become more susceptible to micro-roughing due to NH4OH and possible metal contamination in BOE chemistry when adding ammonium fluoride.
Key Words: Defects, Polysilicon Holes, Semiconductor Process, Yield Improvement. |