Epi resistivity profiles without wafer damage

Non-contact methods are now available to measure the resistivity of silicon epitaxy. The new technology offers wafer manufacturers the opportunity to significantly lower operating costs and increase reactor capacity by eliminating the need for monitor wafers. Our group investigated the Epimet Model 2 (SemiTest, Inc.) for monitoring epi wafer production. Our evaluation shows suitable measurement repeatability, reproducibility, and stability for the epi parts tested. Further, the Epimet significantly outperforms the Hg-probe CV in head-to-head measurement capability comparison. This paper focuses on the product-wafer integrity tests performed which demonstrated that the Epimet is indeed non-contaminating and non-damaging to wafers, allowing it to be used to monitor actual product wafers.