Browse Prior Art Database

Sc2O3 in Place of Al2O3 as an Etch Stop Layer

IP.com Disclosure Number: IPCOM000119788D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Hodgson, RT: AUTHOR [+3]

Abstract

Disclosed is the use of a Sc2O3 layer, deposited by sputtering or alternative methods, for an Al2O3 layer which etches at a much faster rate in CF4 plasmas for all the power conditions investigated. Etch rate data indicate that the etch rate of Sc2O3 is slower by at least a factor of 10-100 than that of Al2O3 . It should therefore be possible to improve the etch rate ratio of SiO2 over an Sc2O3 etch stop layer, which ratio is Z 10-20 in the case of Al2O3, as compared to Z 100-1000 in the case of Sc2O3 . Therefore, by incorporating Sc2O3 in chip or packaging structures as an etch stop layer, the improved etch selectivity of SiO2 over the etch stop layer should greatly facilitate the processing.

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Sc2O3 in Place of Al2O3 as an Etch Stop Layer

      Disclosed is the use of a Sc2O3 layer, deposited by sputtering
or alternative methods, for an Al2O3 layer which etches at a much
faster rate in CF4 plasmas for all the power conditions investigated.
Etch rate data indicate that the etch rate of Sc2O3 is slower by at
least a factor of 10-100 than that of Al2O3 .  It should therefore be
possible to improve the etch rate ratio of SiO2 over an Sc2O3 etch
stop layer, which ratio is Z 10-20 in the case of Al2O3, as compared
to Z 100-1000 in the case of Sc2O3 .  Therefore, by incorporating
Sc2O3 in chip or packaging structures as an etch stop layer, the
improved etch selectivity of SiO2 over the etch stop layer should
greatly facilitate the processing.

      It is assumed that the high etch resistance of Sc2O3 to plasma
etching in CF4 or similar fluorine-based discharges is not specific
to Sc and should apply equally to the other members of group IIIB
elements, i.e., Y, La and Ac.  In fact, the oxides of these elements
in showing similar etch stop properties as Sc2O3 may even turn out to
be easier to handle from other processing points of view, i.e., oxide
deposition, removal of the etch stop layer after plasma etching, etc.
Additionally etch stop layers consisting of the oxides of Y, La and
Ac are contemplated in this application.

      Disclosed anonymously.