Abstract An interconnection pattern made of aluminum alloy, such as Al-Cu, on a semiconductor IC is dry etched in an etching gas. When an etching gas containing chlorine is used, residual chlorine on the substrate is difficult to remove, and causes corrosion of the patterned aluminum alloy layer. According to the present invention, the photo resist stripping process following the etching process is carried out by a downstream stripping process using a conventional etching gas, such as CF₄ + O₂, at room temperature, and, before the resist-stripped substrate is exposed to the atmosphere, the substrate is heated in a vacuum at higher than 100°C, thus the residual chlorine component is removed. The heating process can be carried out concurrently during the resist stripping process. By this means corrosion of the aluminum alloy interconnection is prevented.
A method for etching an aluminum alloy pattern on a semiconductor substrate, comprising the steps of: forming a layer of aluminum alloy on a semiconductor substrate having an insulation layer thereon; forming a resist pattern on said aluminum alloy layer; etching an exposed portion of said aluminum alloy layer by the use of said resist pattern as a mask, whereby said aluminum alloy layer is patterned; stripping said resist pattern in an atmosphere containing a reactive species; and heating the substrate in a vacuum at a temperature higher than 100°C, whereby residual etching agent on the substrate is removed, said heating step being carried out concurrently with said stripping step or after said stripping step.
Claim 2
Independent Claim
115 words
A method for etching an aluminum alloy pattern on a semiconductor substrate, comprising the steps of: forming a layer of aluminum alloy on a semiconductor substrate having an insulation layer thereon; forming a resist pattern on said aluminum alloy layer; etching an exposed portion of said aluminum alloy layer by the use of said resist pattern as a mask, whereby said aluminum alloy layer is patterned; stripping said resist pattern in an atmosphere containing a reactive species; and heating the substrate in a vacuum at a temperature higher than 100°C, whereby residual etching agent on the substrate is removed, said heating step being carried out concurrently with said stripping step or after said stripping step.
Claim 3
Dependent Claim
17 words
A method according to claim 1 wherein said etching is carried out by a dry etching method.
Claim 4
Dependent Claim
21 words
A method according to claim 2 wherein said dry etching is carried out by the use of a gas containing chlorine.
Claim 5
Dependent Claim
27 words
A method according to claim 3 wherein said gas is chosen from the group of chlorine gas, silicon tetrachloride gas, boron trichloride gas, and carbon tetrachloride gas.
Claim 6
Independent Claim
19 words
A method according to any preceding claim wherein the temperature in said heating step is lower than approximately 400°C.
Claim 7
Independent Claim
23 words
A method according to any preceding claim, wherein said reactive species are produced from a mixture of a fluorinated gas and oxygen gas.
Claim 8
Independent Claim
27 words
A method according to any one of claims 1 to 5, wherein said reactive species are produced from a mixture of a nitrogen-containing gas and oxygen gas.
Claim 9
Independent Claim
22 words
A method according to any preceding claim, wherein said reactive species is produced by excitation by microwave power of approximately 2.45 GHz.
Claim 10
Independent Claim
15 words
A method according to any preceding claim wherein said aluminum alloy is an aluminum-copper alloy.
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