Browse Prior Art Database

Selective Rie Of TiW Films

IP.com Disclosure Number: IPCOM000049328D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Logan, JS: AUTHOR [+3]

Abstract

This method allows TiW to be etched by RIE (reactive ion etching) at a high rate and with good selectivity over Al, AlCu alloys, Si(3)N(4), SiO(2) and silicon.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Selective Rie Of TiW Films

This method allows TiW to be etched by RIE (reactive ion etching) at a high rate and with good selectivity over Al, AlCu alloys, Si(3)N(4), SiO(2) and silicon.

TiW (10 wt% Ti) is used to form contacts for low barrier-height Schottky barrier diodes. It is also used as a diffusion barrier between Al and Si at semiconductor device contacts. TiW is most practically deposited by sputtering and, therefore, cannot be patterned by a lift-off technique, as used for patterning AlCu interconnection metallization. A solution to this problem is to deposit the metal film used for the interconnection pattern, e.g., Al, AlCu or AlCu/Hf/AlCu, through a lift-off stencil onto a blanket film of TiW. The unwanted TiW is then removed by a blanket etch. This requires a high ratio between the etch rates of TiW and Al, AlCu, or AlCu/Hf/AlCu so as to selectively etch TiW without attacking the interconnection metallization pattern. The ratios of etch rates of TiW and Si(3)N(4), SiO(2) or Si should also be high so as to selectively etch TiW without attacking the underlayers of SiO(2), Si(3)N(4) or silicon.

Described is a method for etching TiW in a CCl(4)O(2) plasma for which the process parameters, plasma composition and cathode temperature are optimized to achieve high etch rate ratios of TiW to AlCu, TiW to Si(3)N(4), and TiW to Si.

The variation of etch rates of TiW, AlCu, Si(3)N(4), and Si with percentage of 0(2) in CCl(4) and with cathode temperature is show...