Browse Prior Art Database

Oxides of Group IIIB Elements As Etch Masks for RIE

IP.com Disclosure Number: IPCOM000120052D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Harper, JME: AUTHOR [+3]

Abstract

Disclosed are masks for Reactive Ion Etching (RIE) which have low etch rates compared to the material to be etched.

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This is the abbreviated version, containing approximately 52% of the total text.

Oxides of Group IIIB Elements As Etch Masks for RIE

      Disclosed are masks for Reactive Ion Etching (RIE) which
have low etch rates compared to the material to be etched.

      Masking materials currently used in Si technology include
photoresist, SiO2, and Si3N4 layers. For demanding applications,
e.g., deep Si trench etching, SiO2 and Si3N4 masking layers are
preferred over photoresist masks because of their superior etch
resistance. The etch rate ratio of Si substrate over masking material
that can be achieved depends on the process conditions, but is in
most instances not greater than 10, especially for fine-line
patterning. For demanding applications, such as very deep Si trench
etching or etching vias through a wafer for Si carrier applications,
these conventional etch masks have insufficient etch resistance.
Masks made of aluminum, copper or Al2O3 are an improvement, but still
have insufficient etch resistance for etching vias through the wafer.

      It has been found that the use of the oxides of the Group IIIB
elements as etch masks for RIE with CF4 and O2 plasmas are suitable
for these applications. These oxides include Sc2O3, Y2O3, La2O3, and
the oxides of the lanthanide elements Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,
Ho, Er, Tm, Yb and Lu. Promethium is not considered practical because
of its level of radioactivity. In the following process description,
Sc2O3 is used as an example of a Group IIIB oxide, for which
experimental confirmation has been obtained as to its ability to
serve as an effective etch mas...