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This article describes novel methods for etching hafnium (Hf) and zirconium (Zr) useful in the fabrication of excimer laser masks for semiconductor manufacturing.
English (United States)
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Method for Etching of Hafnium And Zirconium Oxide Metal Layers
This article describes novel methods for etching hafnium (Hf) and zirconium
(Zr) useful in the fabrication of excimer laser masks for semiconductor
Currently an ion milling process is utilized on hafnium and zirconium oxides
because there is no known wet or dry etch process. Ion milling is costly, non-
repeatable and generates particulates which are undesirable in a semiconductor
One of the basic principles of dry etch chemistry is that the reaction
product(s) must be volatile in order to be removed from the vacuum chamber.
For most elements, e.g., silicon, chromium, titanium, a tetrachloride, tetraflouride
or oxychloride are formed during dry etching. However, the dry etch by-products
of HfO2 are non-volatile.
A volatile Hf by-product can be produced chemically as follows:
HfO2 -----> HfCl4 -----> HfOCl2
Reducing Volatile at
ZrO2 -----> ZrCl4 + ZrOCl2 -----> ZrOCl2
A dry etch process can be accomplished by either of the
following: 1) HfO2 or ZrO2 2) HfO2 or ZrO2
Cl2/H2 HCl/Cl2 or CCl4
HfCl4 or ZrCl4 HfCl4 or ZrCl4
H2O rinse or H2O rinse or
Plasma moist air Plasma moist air
HfCl2O or ZrCl2O HfCl2O or ZrCl2O