Studies of a new chemical etching method-152 Secco Etch in failure analysis of wafer fabrication

Abstract

Crystalline defects on silicon substrates affect the wafer fabrication yield. Secco Etch is a chemical etching method used to delineate crystalline defects on silicon wafer substrates. When Secco Etch is used directly, crystalline defects can be revealed on silicon substrates after 2 minutes on some areas. However, it does not fully deprocess the substrate layers where severe overetching occurs, even for etch times of up to 20 minutes. After delayering by using dry and wet etches and subsequent Secco Etch, crystalline defects were revealed. However, the delayering method is both time consuming and more costly, as it requires a long time to delayer. To reduce failure analysis cycle time, a new chemical etching method, 152 Secco Etch, has been proposed in this study. In 152 Secco Etch, hydrofluoric acid (HF) is used for deprocessing prior to Secco etch for wafer fabrication failure analysis applications. Analytical results show that 152 Secco Etch is a rapid and reliable chemical method and is effective in revealing crystalline silicon defects.