Production Process
We post-process polished wafers into the following four types of silicon wafers.
Annealed Wafer
Polished wafers are annealed in hydrogen or argon atmospheres provide improved near surface crystalline perfection.
Epitaxial Wafers (EW)
In case crystal perfection or multi-layers with different resistivities is required by the customers, a thin single crystalline layer called epitaxial layer is grown on the surface of a polished wafer by CVD (chemical vapor deposition) process.
Junction Isolated Wafers (JIW)
Junction Isolated Wafer is epitaxial wafer with buried layers produced with patterns of IC, meeting customers' designs by using photolithography, ion-implantation, and thermal diffusion.
Silicon-On-Insulator Wafers (SOI Wafers)
By heat treatment on an oxidized handle wafer directly bonded with an active wafer (on which devices are to be made), the handle wafer's oxide layer and the active wafer's silicon are joined together. The bonded wafer is then ground and polished on the active wafer side.
