Abstract: A method for forming shallow trench isolation (STI) structure including providing a substrate comprising an overlying hardmask layer; patterning the hardmask layer to form a hardmask layer opening for etching a trench through a substrate thickness portion; etching a trench according to the patterned overlying hardmask layer; carrying out a wet chemical oxidizing process to form an oxidized surface portion on the hardmask layer; carrying out a wet chemical etching process to remove at least a portion of the oxidized surface portion to form the hardmask opening having an enlarged width and the trench opening comprising rounded upper corners; and, forming a completed planarized STI structure filled with oxide.

Abstract: A process for forming a semiconductor device with multiple gate insulator thicknesses, wherein exposed surfaces of a semiconductor substrate are protected during a photoresist stripping procedure, has been developed. After growth of an insulator layer on the entire surface of a semiconductor substrate portions of the insulator layer not covered by a photoresist masking shape are selectively removed. A two step photoresist removal procedure is then employed initiating with an ozone water cycle which partially removes the photoresist shape while forming a thin silicon oxide layer on the portions of bare semiconductor surface. A acid-hydrogen peroxide mixture (SPM), is then used to complete the photoresist removal procedure including removal of photoresist residues, with the thin silicon oxide layer formed during the ozone water cycle protecting the previously bare underlying semiconductor surface.