Method to remove metals in a scrubber
AssigneeLam Research Corporation
InventorsWilbur C. Krusell, Igor J. Malik
Life of this patent
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Abstract
A method to remove metal contaminants in a substrate cleaning process. The present invention may replace or be used in conjunction with other substrate cleaning systems. This method comprises adding a citric acid solution to the liquid medium of a semiconductor substrate cleaning system. This method is described in the manner it is used in conjunction with a scrubber wherein both sides of a wafer are scrubbed.
Claims19
A method to simultaneously reduce surface metals and particulates in a scrubber comprising:
- providing a semiconductor substrate;
- placing said substrate in a scrubber;
- scrubbing said substrate;
- and
- adding an acid solution to said scrubber while scrubbing said substrate, wherein said acid solution comprises an acid selected from the group consisting of:
- citric acid, oxalic acid, di-ammonium citrate, and any combination thereof.
A method for removing surface metal contaminants from substrate surfaces in a scrubber comprising:
- providing a semiconductor substrate;
- keeping said substrate wet after one of:
- polishing and epitaxial silicon deposition, and prior to scrubbing;
- placing said substrate in a scrubber;
- scrubbing said substrate in a scrubber solution;
- and
- adding a solution comprising citric acid to said scrubber solution while scrubbing said substrate.
A method for removing surface metal contaminants from hydrophilic substrate surfaces in a scrubber comprising:
- providing a semiconductor substrate;
- keeping said substrate wet after one of:
- polishing and epitaxial silicon deposition, and prior to scrubbing;
- placing said substrate in a scrubber;
- scrubbing said substrate in a scrubber solution;
- and
- adding a solution comprising citric acid to said scrubber solution while scrubbing said substrate, wherein said solution comprising citric acid is approximately 0.05-10.0 wt. percent of citric acid, and wherein said scrubber solution has a pH level in the range of approximately 0-2.8 after said solution comprising citric acid is added.
A method to remove particles, metals, and surface organic films after chemical mechanical polishing comprising:
- providing a semiconductor substrate;
- polishing said substrate;
- keeping said substrate wet after polishing and prior to scrubbing;
- placing said substrate in a scrubber;
- and
- scrubbing said substrate in a scrubber solution comprising dilute surfactants and a reagent,
- wherein said dilute surfactants comprise acid detergents,
- wherein said reagent comprises an acid, wherein said acid is selected from the group consisting of:
- citric acid, oxalic acid, di-ammonium citrate, and any combination thereof, and
- wherein said scrubber solution containing said reagent has a pH level in the range of 1.6-2.8.
A method to reduce deposition and redeposition of particles in a wafer cleaning process comprising:
- providing a semiconductor substrate;
- placing said substrate in a solution;
- and
- setting up a zeta potential repulsion between a particle and a surface of said substrate,
- wherein said zeta potential is a positive-to-positive repulsion,
- wherein said cleaning solution sets up said zeta potential,
- wherein said cleaning solution has a pH level in the range of approximately 0-2.8, and
- wherein said cleaning solution comprises an acid, wherein said acid is selected from the group consisting of:
- di-ammonium citrate, citric acid, oxalic acid, and any combination thereof.
A method of processing a substrate comprising:
- processing a semiconductor substrate in a first processing operation;
- processing said substrate in a second processing operation;
- and
- maintaining said substrate in a solution comprising an acid, wherein said acid is selected from the group consisting of:
- citric acid, di-ammonium citrate, oxalic acid, and any combination thereof.
A method for removing surface metal contaminants from substrate surfaces in a scrubber comprising:
- providing a semiconductor substrate;
- placing said substrate in a scrubber;
- scrubbing said substrate in a scrubber solution;
- and
- adding a solution comprising citric acid to said scrubber while scrubbing said substrate.
A method to remove particles, metals, and surface organic films after chemical mechanical polishing comprising:
- providing a semiconductor substrate;
- polishing said substrate;
- placing said substrate in a scrubber;
- and
- scrubbing said substrate in a scrubber solution comprising dilute surfactants and a reagent;
- wherein said reagent comprises an acid selected from the group consisting of:
- citric acid, oxalic acid, di-ammonium citrate, and any combination thereof.
Dependencies are inferred from the claim text.