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

Abstract

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.

Dependencies are inferred from the claim text.