Process for implanting a deep subcollector with self-aligned photo registration marks

摘要

A method of forming a BiCMOS device having a deep subcollector region and self-aligned alignment marks is provided. The inventive method includes the steps of: (a) lithographically forming a first patterned layer comprising a thick dielectric material on a surface of a material stack formed on a semiconductor substrate, the first patterned layer including at least one opening therein and the semiconductor substrate having at least an alignment area; (b) performing a high-energy/high-dose implant through the at least one opening and the material stack so as to form at least one deep subcollector region in the semiconductor substrate; (c) lithographically forming a second patterned layer (photoresist or dielectric) predominately outside the first patterned layer in the alignment area; and (d) etching through the material stack to form alignment marks in the underlying semiconductor substrate using the first patterned layer as an alignment mark mask.