Corrosion-free aluminum etching process for fabricating an integrated circuit structure

Claim 2

A process for etching aluminum on a semiconductor wafer without forming corrosive residues which comprises etching the aluminum in a vacuum chamber using: a) one or more bromine-containing gases selected from the group consisting of BBr 3 , HBr, Br 2 , CF 3 Br, CF 2 Br 2 , CFBr 3 , CBr 4 , CHBr 3 , CH 2 Br, and mixtures of same; and b) SF 6 gas in an amount equal to from about 1 to about 30 volume % of the combined total of said one or more bromine-containing gases and said SF 6 gas; to thereby etch said aluminum layer without leaving corrosion-forming chlorine etch residues on said semiconductor wafer.

Claim 3

The process of claim 1 wherein said one or more bromine-containing gases are flowed into said vacuum chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber.

Claim 4

The process of claim 2 wherein a plasma is ignited in said vacuum chamber during said etching.

Claim 5

The process of claim 3 wherein the power level of said plasma in said chamber is maintained within a range of from about 0.5 to about 2.75 watts per cm 2 of wafer area.

Claim 6

The process of claim 3 wherein said wafer is immersed in a magnetic field horizontal to the plane of said wafer during said etch.

Claim 7

The process of claim 5 wherein the strength of said magnetic field ranges from 0 to about 200 gauss.

Claim 8

The process of claim 5 wherein the pressure in said vacuum chamber is maintained with a range of from about 2 to about 100 milliTorr.

Claim 9

The process of claim 7 wherein the temperature in said vacuum chamber is maintained within a range of from about 0° to about 150° C.

Claim 10

The process of claim 7 wherein the temperature in said vacuum chamber is maintained within a range of from about 70° C. to about 100° C.

Claim 11

A process for etching an aluminum layer on a semiconductor wafer, having a patterned photoresist mask formed over said aluminum layer, without forming corrosive residues which comprises: (a) inserting said wafer into a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and at a temperature within a range of from about 0° to about 150° C.; (b) flowing into said vacuum etch chamber one or more bromine-containing gases selected from the group consisting of BBr 3 HBr, Br 2 , CF 3 Br, CF 2 Br 2 , CFBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; (c) flowing SF 6 gas into said vacuum etch chamber in an amount equal to from about 1 to about 30 volume % of the combined total of said one or more bromine-containing gases and said SF 6 gas; (d) igniting a plasma in said vacuum etch chamber; and (e) optionally immersing said wafer in a magnetic field parallel to the plane of the wafer; to thereby etch said masked aluminum layer without leaving corrosion-forming chlorine etch residues on said semiconductor wafer.

Claim 12

A process for etching an aluminum layer on a semiconductor wafer, having a patterned photoresist mask formed over said aluminum layer, without forming corrosive residues which comprises: (a) inserting said wafer into a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and at a temperature within a range of from about 0° to about 150° C.; (b) flowing into said vacuum etch chamber one or more bromine-containing gases selected from the group consisting of BBr 3 HBr, Br 2 , CF 3 Br, CF 2 Br 2 , CFBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; (c) flowing SF 6 gas into said vacuum etch chamber in an amount equal to from about 1 to about 30 volume % of the combined total of said one or more bromine-containing gases and said SF 6 gas; (d) igniting a plasma in said vacuum etch chamber; and (e) optionally immersing said wafer in a magnetic field parallel to the plane of the wafer; to thereby etch said masked aluminum layer without leaving corrosion-forming chlorine etch residues on said semiconductor wafer.

Claim 13

The process of claim 10 wherein said one or more bromine-containing gases are flowed into said vacuum chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber.

Claim 14

The process of claim 10 wherein the power level of said plasma in said chamber is maintained within a range of from about 0.5 to about 2.75 watts per of wafer area.

Claim 15

The process of claim 10 wherein the field strength of said optional magnetic field ranges from 0 to about 200 gauss.

Claim 16

The process of claim 10 wherein said bromine-containing gas comprises BBr 3 .

Claim 17

A process for etching an aluminum layer while fabricating an integrated circuit structure on a semiconductor wafer, having a patterned photoresist mask formed over said aluminum layer, without forming corrosive residues which comprises: (a) positioning said wafer in a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and a temperature within a range of from about 70° C. to about 100° C.; (b) flowing into said vacuum etch chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber, one or more bromine-containing gases selected from the group consisting of BBr 3 , HBr, Br 2 , CF 3 Br, CFBr 3 , CBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; (c) flowing into said vacuum etch chamber, with said one or more bromine-containing gases, SF 6 gas in an amount ranging from about 1 to about 30 volume % of the combined total of said SF 6 and said one or more bromine-containing gases; (d) igniting a plasma in said vacuum etch chamber; (e) maintaining said plasma in said vacuum chamber during said etch at a power level within a range of from about 0.5 to about 2.75 watts per cm 2 of wafer area; (f) optionally immersing said wafer during said etch in a magnetic field parallel to the plane of the wafer and having a field strength ranging from 0 to about 200 gauss; and (g) carrying out said etch for a period of from about 25 seconds to about 20 minutes; thereby etch said masked aluminum layer at an increased etch rate over the use of said one or more bromine-containing gases without said SF 6 gas, without leaving corrosion-forming chlorine etch residues on said integrated circuit structure.

Claim 18

A process for etching an aluminum layer while fabricating an integrated circuit structure on a semiconductor wafer, having a patterned photoresist mask formed over said aluminum layer, without forming corrosive residues which comprises: (a) positioning said wafer in a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and a temperature within a range of from about 70° C. to about 100° C.; (b) flowing into said vacuum etch chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber, one or more bromine-containing gases selected from the group consisting of BBr 3 , HBr, Br 2 , CF 3 Br, CFBr 3 , CBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; (c) flowing into said vacuum etch chamber, with said one or more bromine-containing gases, SF 6 gas in an amount ranging from about 1 to about 30 volume % of the combined total of said SF 6 and said one or more bromine-containing gases; (d) igniting a plasma in said vacuum etch chamber; (e) maintaining said plasma in said vacuum chamber during said etch at a power level within a range of from about 0.5 to about 2.75 watts per cm 2 of wafer area; (f) optionally immersing said wafer during said etch in a magnetic field parallel to the plane of the wafer and having a field strength ranging from 0 to about 200 gauss; and (g) carrying out said etch for a period of from about 25 seconds to about 20 minutes; thereby etch said masked aluminum layer at an increased etch rate over the use of said one or more bromine-containing gases without said SF 6 gas, without leaving corrosion-forming chlorine etch residues on said integrated circuit structure.

Claim 19

The process of claim 15 wherein said bromine-containing gas comprises BBr 3 .

Claim 20

A process for etching an aluminum layer to form a pattern of aluminum lines while fabricating an integrated circuit structure on a semiconductor wafer, without forming corrosive residues which comprises: (a) forming a patterned photoresist mask over said aluminum layer on said wafer; (b) inserting said wafer into a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and a temperature within a range of from about 70° C. to about 100° C.; (c) flowing into said vacuum etch chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber: (i) one or more bromine-containing gases selected from the group consisting of BBr 3 , HBr, Br 2 , CF 3 Br, CF 2 Br 2 , CFBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; and (ii) SF 6 gas in an amount equal to from about 1 to about 30 volume % of the combined total of said one or more bromine-containing gases and said SF 6 gas; (d) igniting a plasma in said chamber; (e) maintaining said plasma in said vacuum chamber during said etch at a power level within a range of from about 0.5 to about 2.75 watts per cm 2 of wafer area; and (f) optionally immersing said wafer during said etch in a magnetic field parallel to the plane of the wafer and having a field strength ranging from 0 to about 200 gauss.

Claim 21

A process for etching an aluminum layer to form a pattern of aluminum lines while fabricating an integrated circuit structure on a semiconductor wafer, without forming corrosive residues which comprises: (a) forming a patterned photoresist mask over said aluminum layer on said wafer; (b) inserting said wafer into a vacuum etch chamber maintained at a pressure within a range of from about 2 to about 100 milliTorr and a temperature within a range of from about 70° C. to about 100° C.; (c) flowing into said vacuum etch chamber at a rate equivalent to from about 10 to about 200 sccm flowing into a 10 liter vacuum chamber: (i) one or more bromine-containing gases selected from the group consisting of BBr 3 , HBr, Br 2 , CF 3 Br, CF 2 Br 2 , CFBr 3 , CBr 4 , CHBr 3 , CH 2 Br 2 , CH 3 Br, and mixtures of same; and (ii) SF 6 gas in an amount equal to from about 1 to about 30 volume % of the combined total of said one or more bromine-containing gases and said SF 6 gas; (d) igniting a plasma in said chamber; (e) maintaining said plasma in said vacuum chamber during said etch at a power level within a range of from about 0.5 to about 2.75 watts per cm 2 of wafer area; and (f) optionally immersing said wafer during said etch in a magnetic field parallel to the plane of the wafer and having a field strength ranging from 0 to about 200 gauss.

Claim 22

The process of claim 17 wherein the amount of said SF 6 gas flowing into said chamber comprises about 25 volume % of the combined total of said SF 6 and said BBr 3 gas to provide an etch rate approximately twice the etch rate obtained using BBr 3 gas along as the etchant gas.