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AssigneeMicron Technology, Inc.
InventorsChris C. Yu, Trung T. Doan
Estimating the term…
A method for forming conductive plugs within an insulation material is described. The inventive process results in a plug of a material such as tungsten which is more even with the insulation layer surface than conventional plug formation techniques. Conventional processes result in recessed plugs which are not easily or reliably coupled with subsequent layers of sputtered aluminum or other conductors. The inventive process uses a two-step chemical mechanical planarization technique. An insulation layer with contact holes is formed, and a metal layer is formed thereover. A polishing pad rotates against the wafer surface while a slurry selective to the metal removes the metal overlying the wafer surface, and also recesses the metal within the contact holes due to the chemical nature and fibrous element of the polishing pad. A second CMP step uses a slurry having an acid or base selective to the insulation material to remove the insulator from around the metal. The slurry also contains abrasive materials which polish the metal surface so as to make the metal level with the insulation layer surface. Removal of the insulation material can continue, thereby producing a slightly protruding plug which result sin a more reliable contact from the substrate to subsequent conductive layers.
A method of producing a conductive plug in an insulation layer, comprising the steps of:
A method of chemical mechanical planarization of an oxide material, comprising the steps of:
A method of producing a conductive plug in an insulation layer, comprising the steps of:
Dependencies are inferred from the claim text.