Ceric-ion slurry for use in chemical-mechanical polishing
AssigneeIntel Corporation
InventorsANNE E. MILLER, A. DANIEL FELLER, KENNETH C. CADIEN
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Abstract
The invention provides a chemical-mechanical polishing slurry comprising a liquid, cerium ions as an oxidizer, an abrasive, and a pH increasing substance. The cerium ions are in the liquid in a quantity equal to the inclusion of at least 0.02 molar ammonium cerium nitrate in the liquid. The abrasive is also included in the liquid. The liquid, the cerium ions and the abrasive jointly have a first pH value. The pH increasing substance increases the first pH value to a second pH value above 1.5.
Claims25
A chemical-mechanical polishing slurry comprising:
- a liquid;
- cerium ions as an oxidizer in the liquid, the cerium ions being in a quantity equal to the inclusion of at least 0.02 molar ammonium cerium nitrate in the liquid;
- an abrasive in the liquid, the liquid, the cerium ions and the abrasive together having a first pH value;
- and
- a pH increasing substance in the liquid that increases the first pH value to a second pH value above 1.5.
A method of preparing a chemical-mechanical polishing slurry, comprising:
- adding together an abrasive and a complex cerium double salt as a source of cerium ions.
A method of forming a metal line, comprising:
- forming a first layer, with an opening therein, over a semiconductor substrate;
- depositing a metal layer which fills the opening and covers the first layer;
- applying a chemical-mechanical polishing slurry onto the metal layer, the slurry comprising cerium ions as an oxidizer, and an abrasive;
- contacting a polishing surface against the metal layer;
- and
- moving the polishing surface over the metal layer.
Dependencies are inferred from the claim text.