Halogen-resistant, anodized aluminum for use in semiconductor processing apparatus
First Claim
1. A high purity aluminum alloy with controlled particulate size and distribution of mobile impurities present in said alloy, said high purity aluminum alloy being employed in the manufacture of semiconductor processing apparatus where exposure to corrosive environments would degrade an aluminum alloy which does not exhibit controlled mobile impurity particulate size and distribution, said high purity aluminum alloy having mobile impurity particulates within specific limits so that at least 95% of all particles are 5 μ
- m or less in size, no more than 5% of said particles range between 20 μ
m and 5 μ
m, and no more than 0.2% of said particles range between 50 μ
m and 20 μ
m.
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Accused Products
Abstract
We have discovered that the formation of particulate inclusions at the surface of an aluminum alloy article, which inclusions interfere with a smooth transition from the alloy surface to an overlying aluminum oxide protective film can be controlled by maintaining the content of mobile impurities within a specific range and controlling the particulate size and distribution of the mobile impurities and compounds thereof; by heat-treating the aluminum alloy at a temperature less than about 330° C.; and by creating the aluminum oxide protective film by employing a particular electrolytic process. When these factors are taken into consideration, an improved aluminum oxide protective film is obtained.
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Citations
27 Claims
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1. A high purity aluminum alloy with controlled particulate size and distribution of mobile impurities present in said alloy, said high purity aluminum alloy being employed in the manufacture of semiconductor processing apparatus where exposure to corrosive environments would degrade an aluminum alloy which does not exhibit controlled mobile impurity particulate size and distribution, said high purity aluminum alloy having mobile impurity particulates within specific limits so that at least 95% of all particles are 5 μ
- m or less in size, no more than 5% of said particles range between 20 μ
m and 5 μ
m, and no more than 0.2% of said particles range between 50 μ
m and 20 μ
m. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- m or less in size, no more than 5% of said particles range between 20 μ
-
8. A method of producing a corrosion-resistant article for use in semiconductor processing apparatus, wherein said article comprises a body formed from high purity aluminum alloy, and wherein at least a surface of said body which is to be exposed to a corrosive environment is covered with an aluminum-oxide-comprising film, and wherein at least said surface of said body which is covered said aluminum-oxide-comprising film is an aluminum alloy having mobile impurity particulates controlled within limits so that at least 95% of all particles are 5 μ
- m or less in size, no more than 5% of said particles range between 20 μ
m and 5 μ
m, and no more than 0.2% of said particles range between 50 μ
m and 20 μ
m. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
- m or less in size, no more than 5% of said particles range between 20 μ
-
17. A method of creating an aluminum oxide protective film on the surface of a high purity aluminum alloy, comprising:
- exposing said surface of said aluminum alloy to an electrolytic oxidation process during which said surface is immersed as an anode in an acid electrolyte, with a cathode comprised of an aluminum alloy, and wherein a DC current is applied, wherein said acid electrolyte is a water-based solution comprising 10% to 20% by weight sulfuric acid and about 0.5% to 3.0% by weight oxalic acid, wherein said protective film is created at a temperature ranging from about 5°
C. to about 25°
C., and wherein an applied current density of said DC current ranges from 5 A/ft2 to 36 A/ft2. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
- exposing said surface of said aluminum alloy to an electrolytic oxidation process during which said surface is immersed as an anode in an acid electrolyte, with a cathode comprised of an aluminum alloy, and wherein a DC current is applied, wherein said acid electrolyte is a water-based solution comprising 10% to 20% by weight sulfuric acid and about 0.5% to 3.0% by weight oxalic acid, wherein said protective film is created at a temperature ranging from about 5°
Specification