Method of plasma etching transition metals and their compounds

1 . A plasma etching method, comprising:

causing carbon monoxide-based plasma to react with a transition metal to form a metal carbonyl gas while simultaneously plasma etching said transition metal.

2 . The plasma etching method according to claim 1 , wherein said transition metal is selected from a group of transition metals consisting of nickel, iron, cobalt, manganese, molybdenum, tungsten and ruthenium.

3 . The plasma etching method according to claim 1 wherein the method further comprises exposing photoresist above the transition metal to transfer a pattern to the photoresist before the causing step.

4 . The plasma etching method according to claim 3 wherein, during the causing step, the pattern is transferred from the photoresist to the transition metal.

5 . A plasma etching method, comprising:

causing carbon monoxide-based plasma to react with a transition metal compound to form a carbonyl gas while simultaneously plasma etching said transition metal compound.

6 . The plasma etching method according to claim 5 , wherein said transition metal compound is selected from a group of transition metal compounds consisting of oxides, nitrides, and silicides.

7 . The plasma etching method according to claim 5 , wherein said transition metal compound is nickel oxide.

8 . The plasma etching method according to claim 5 wherein the method further comprises exposing photoresist above the transition metal compound to transfer a pattern to the photoresist before the causing step.

9 . The plasma etching method according to claim 8 wherein, during the causing step, the pattern is transferred to the transition metal compound.

10 . A method of etching, comprising:

using carbon monoxide-based plasma to plasma etch a selected transition metal; and

forming a volatile metal carbonyl by-product.

11 . The method according to claim 10 , wherein said volatile metal carbonyl by-product is in the form of a gas.

12 . The method according to claim 10 , wherein said volatile metal carbonyl by-product is a liquid.

13 . The method according to claim 10 , wherein said carbon monoxide-based plasma acts as a reducing agent.

14 . The method according to claim 10 , the method further comprising exposing photoresist above the selected transition metal to transfer a pattern to the photoresist before the step of using carbon monoxide-based plasma to plasma etch the selected transition metal.

15 . The method according to claim 14 wherein, during the step of using carbon monoxide-based plasma to plasma etch a selected transition metal, the pattern is transferred to the selected transition metal.

16 . A method of etching, comprising:

using carbon monoxide-based plasma to plasma etch a selected transition metal compound; and

forming a volatile by-product of metal carbonyl.

17 . The method according to claim 16 , wherein said volatile by-product of metal carbonyl is a gas.

18 . The method according to claim 16 , wherein said volatile by-product of metal carbonyl is a liquid.

19 . The method according to claim 16 , wherein said carbon monoxide-based plasma acts as a reducing agent.

20 . The method according to claim 16 , the method further comprising exposing photoresist above the selected transition metal compound to transfer a pattern to the photoresist before the step of using carbon monoxide-based plasma to plasma etch the selected transition metal compound.

21 . The method according to claim 20 wherein, during the step of using carbon monoxide-based plasma to plasma etch a selected transition metal compound, the pattern is transferred to the selected transition metal compound.

22 . A method of etching, comprising:

exposing any one of the following:

a transition metal; or

a transition metal oxide; or

a transition metal compound;

to a primary etchant to plasma etch and form a metal carbonyl by-product.

23 . The method of etching according to claim 22 , wherein said primary etchant is carbon monoxide plasma.

24 . The method of etching according to claim 23 , wherein said metal carbonyl by-product is a gas.

25 . The method of etching according to claim 23 , wherein said metal carbonyl by-product is a liquid.

26 . The method of etching according to claim 23 , wherein said transition metal oxide is nickel oxide.

27 . The method of etching according to claim 23 , wherein other gas or gases are introduced with said carbon monoxide plasma.

28 . The method of etching according to claim 27 , wherein said other gas or gases are selected from a group of gases consisting of: reducing agents, passivants, and gases providing ion assistance.

29 . The method of etching according to claim 26 wherein said nickel oxide is stacked with at least one other conducting material.

30 . The method of etching according to claim 29 , wherein said at least one other conducting material is titanium nitride.

31 . The method of etching according to claim 26 wherein said nickel oxide is stacked with at least one other insulating material.

32 . The method according to claim 26 , further comprising:

using a passivant to assist the carbon monoxide gas plasma in etching said nickel oxide.

33 . The method according to claim 32 , wherein said passivant is N 2 .

34 . The method according to claim 22 , wherein a reducing agent is required.

35 . The method according to claim 34 , wherein said reducing agent additive is selected from a group of additives consisting such as of: CH 2 F 2 , H 2 , and CH 3 F.

36 . The method according to claim 26 , wherein said nickel oxide is disposed about a layer of titanium nitride.

37 . The method according to claim 36 , wherein said titanium nitride is etched with Cl 2 , BCl 3 , HBr or other fluorocarbon gases as primary etchants.

38 . The method according to claim 22 wherein a layer of photoresist above the transition metal, transition metal oxide, or transition metal compound is developed to transfer a pattern to the layer of photoresist.

39 . The method according to claim 38 wherein the pattern is transferred to the transition metal, transition metal oxide, or transition metal compound during the exposing step.

40 . A method of forming a nonvolatile memory cell, comprising:

forming a vertically oriented semiconductor junction diode;

forming a transition metal layer, or a transition metal oxide layer, or a transition metal compound layer about said diode; and

plasma etching said transition metal layer, transition metal oxide layer, or transition metal compound layer structure with carbon monoxide to cause gaseous metal carbonyl by-product to be formed as a by-product.

41 . The method of claim 40 wherein the nonvolatile memory cell resides in a monolithic three dimensional memory array.