Method for depositing an al2 O3 cap layer on an integrated circuit substrate

Claim 1

A method for fabricating an integrated circuit wafer, comprising the steps of: (a) positioning a thermally oxidized silicon wafer on a substrate holding fixture in a vacuum chamber; (b) evacuating said vacuum chamber; (c) introducing argon gas into said vacuum chamber until a first sputtering pressure of about 6×10 -3 TORR. is attained; (d) depositing an aluminum layer on said silicon wafer by sputtering an aluminum target at said first sputtering pressure until said aluminum layer reaches a thickness of about 1 micron; (e) evacuating said vacuum chamber to a pressure in the mid 10 -7 TORR. range; (f) introducing a gas mixture of argon and oxygen into said vacuum chamber until a second sputtering pressure of about 1×10 -2 TORR. is reached; (g) depositing an aluminum oxide layer on said aluminum layer by sputtering said aluminum target at said second sputtering pressure until said aluminum oxide layer attains a thickness of about 300 Angstroms; (h) providing a desired resist pattern on said aluminum oxide layer; (i) etching said aluminum and aluminum oxide layers whereby said aluminum oxide layer prevents etching acids from forming mouse bites or notches in said aluminum layer; and (j) annealing said semi-conductor chip whereby said aluminum oxide layer manifests reduced film stress after heating.

Claim 2

A method for fabricating an integrated circuit wafer, comprising the steps of: (a) positioning a thermally oxidized silicon wafer on a substrate holding fixture in a vacuum chamber; (b) evacuating said vacuum chamber; (c) introducing argon gas into said vacuum chamber until a first sputtering pressure of about 6×10 -3 TORR. is attained; (d) depositing an aluminum layer on said silicon wafer by sputtering an aluminum target at said first sputtering pressure until said aluminum layer reaches a thickness of about 1 micron; (e) evacuating said vacuum chamber to a pressure in the mid 10 -7 TORR. range; (f) introducing a gas mixture of argon and oxygen into said vacuum chamber until a second sputtering pressure of about 1×10 -2 TORR. is reached; (g) depositing an aluminum oxide layer on said aluminum layer by sputtering said aluminum target at said second sputtering pressure until said aluminum oxide layer attains a thickness of about 300 Angstroms; (h) providing a desired resist pattern on said aluminum oxide layer; (i) etching said aluminum and aluminum oxide layers whereby said aluminum oxide layer prevents etching acids from forming mouse bites or notches in said aluminum layer; and (j) annealing said semi-conductor chip whereby said aluminum oxide layer manifests reduced film stress after heating.

Claim 10

A method for fabricating an integrated circuit wafer in order to reduce film stress, the formation of mouse bites and notches during an etching step and to increase light absorption during a patterning step, said method comprising the steps of: positioning a thermally oxidized silicon wafer on a substrate holding fixture in a vacuum chamber; introducing argon gas into said vacuum chamber until a first sputtering pressure of about 6×10 -3 TORR. is attained; depositing a layer of aluminum on said substrate by sputering with argon gas at said first sputtering pressure until said aluminum layer reaches a thickness of about 1 micron; depositing a layer of aluminum oxide on said aluminum layer by sputtering with an argon-oxygen gas mixture at a second pressure of about 1×10 -2 TORR. until said aluminum oxide layer attains a thickness of about 300 Angstroms; photolithographically patterning a resist such that said aluminum oxide layer provides increased absorption of light during photolithography; etching said aluminum and aluminum oxide layers, whereby said aluminum oxide layer reduces formation of mouse bites and notches on said aluminum layer; and annealing said semi-conductor chip whereby said aluminum oxide layer manifests reduced film stress.

Claim 11

A method for fabricating an integrated circuit wafer in order to reduce film stress, the formation of mouse bites and notches during an etching step and to increase light absorption during a patterning step, said method comprising the steps of: positioning a thermally oxidized silicon wafer on a substrate holding fixture in a vacuum chamber; introducing argon gas into said vacuum chamber until a first sputtering pressure of about 6×10 -3 TORR. is attained; depositing a layer of aluminum on said substrate by sputering with argon gas at said first sputtering pressure until said aluminum layer reaches a thickness of about 1 micron; depositing a layer of aluminum oxide on said aluminum layer by sputtering with an argon-oxygen gas mixture at a second pressure of about 1×10 -2 TORR. until said aluminum oxide layer attains a thickness of about 300 Angstroms; photolithographically patterning a resist such that said aluminum oxide layer provides increased absorption of light during photolithography; etching said aluminum and aluminum oxide layers, whereby said aluminum oxide layer reduces formation of mouse bites and notches on said aluminum layer; and annealing said semi-conductor chip whereby said aluminum oxide layer manifests reduced film stress.

Claim 13

A method of forming a cap layer of aluminum oxide on an aluminum layer on a substrate for reducing film stress and the number of mouse bites and notches in said aluminum layer, comprising the steps of: depositing about a 1 micron thick layer of aluminum on said substrate, using an argon sputtering gas at a first pressure of about 6×10 -3 TORR. wherein deposition of said aluminum layer occurs at a rate of 1400 Å/min. using a power setting of 8.5 Kw; depositing about a 300 Angstrom thick layer of aluminum oxide on said aluminum layer by sputtering aluminum in the presence of argon and oxygen gas at a second pressure of about 1×10 -2 TORR., wherein deposition of said aluminum oxide layer occurs at a rate of 115 Å/min. using a power setting of 2.5 Kw; photolithographically patterning a resist such that said aluminum oxide layer provides increased absorption of light during patterning; and etching said layers wherein said aluminum oxide layer reduces formation of mouse bites and notches in said aluminum layer.

Claim 14

A method of forming a cap layer of aluminum oxide on an aluminum layer on a substrate for reducing film stress and the number of mouse bites and notches in said aluminum layer, comprising the steps of: depositing about a 1 micron thick layer of aluminum on said substrate, using an argon sputtering gas at a first pressure of about 6×10 -3 TORR. wherein deposition of said aluminum layer occurs at a rate of 1400 Å/min. using a power setting of 8.5 Kw; depositing about a 300 Angstrom thick layer of aluminum oxide on said aluminum layer by sputtering aluminum in the presence of argon and oxygen gas at a second pressure of about 1×10 -2 TORR., wherein deposition of said aluminum oxide layer occurs at a rate of 115 Å/min. using a power setting of 2.5 Kw; photolithographically patterning a resist such that said aluminum oxide layer provides increased absorption of light during patterning; and etching said layers wherein said aluminum oxide layer reduces formation of mouse bites and notches in said aluminum layer.