High aspect ratio and reduced undercut trench etch process for a semiconductor substrate

Patent metadata

Field	Value
Publication number	US-8928124-B2
Application number	US-201313965511-A
Country	US
Kind code	B2
Filing date	Aug 13, 2013
Priority date	Oct 26, 2011
Publication date	Jan 6, 2015
Grant date	Jan 6, 2015

Abstract

A hydrofluorocarbon gas is employed as a polymer deposition gas in an anisotropic etch process employing an alternation of an etchant gas and the polymer deposition gas to etch a deep trench in a semiconductor substrate. The hydrofluorocarbon gas can generate a thick carbon-rich and hydrogen-containing polymer on sidewalls of a trench at a thickness on par with the thickness of the polymer on a top surface of the semiconductor substrate. The thick carbon-rich and hydrogen-containing polymer protects sidewalls of a trench, thereby minimizing an undercut below a hard mask without degradation of the overall rate. In some embodiments, an improvement in the overall etch rate can be achieved.

First claim

What is claimed is:

1. A semiconductor structure comprising:
a stack of a semiconductor substrate and a mask layer having an opening therein;
a trench located within said semiconductor substrate and underlying said opening and having a vertically modulated width; and
a hydrofluorocarbon polymer layer contiguously extending from a top surface and sidewalls of said mask layer, through sidewalls of said trench, and to a bottom surface of said trench, wherein said hydrofluorocarbo…

Assignees

• IBM
• Zeon Corp

Inventors

• Fuller Nicholas C M
• Joseph Eric A
• Sikorski Edmund M
• Matsuura Goh

Classifications

• H10P50/244

  Electricity · mapped topic

• H10W20/023 Primary

  Electricity · mapped topic

• H10W20/0245

  Electricity · mapped topic

• H10D62/117 Primary

  Electricity · mapped topic

• H01L21/30655

  Electricity · mapped topic