Method for the etchback of a conductive material
AssigneeApplied Materials, Inc.
InventorsChris Ting, Janet Yu
Life of this patent
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Abstract
The present disclosure provides a method for etchback of a conductive layer in a contact via (contact hole). The method described is typically used in the formation of a conductive plug within the contact hole. The method includes a first etchback in which the conductive layer is etched back; a buffer (i.e., transition) step during which the etch rate of the conductive layer is reduced; and a second etchback in which the amount of chemically reactive etchant is reduced from that used in the first etchback and a plasma species is added to provide additional physical bombardment, in an isotropic etch of the substrate surface surrounding the contact hole.
Claims30
A method of etching back a conductive material layer within a semiconductor structure, wherein said semiconductor structure comprises a substrate including a conductive region to be connected, a dielectric layer formed over said substrate and defined with a contact hole therein which overlies said conductive region, and a conductive layer deposited within said contact hole, wherein said method comprises the steps of:
- a) a first etchback to remove a portion of said conductive layer, wherein said first etchback is performed using a plasma generated from a source gas comprising SF6 and a carrier gas selected from the group consisting of N2, argon, and combinations thereof, and wherein said SF6 and said carrier gas are present in said source gas in an atomic ratio of about 6:1 to about 48:1;
- b) a buffer step to slow the etch rate of said conductive layer, wherein a plasma source power or a substrate bias power or both are discontinued or reduced relative to a plasma source power or a substrate bias power used in said first etchback;
- and
- c) a second etchback to remove residues of said conductive layer from an upper surface of said substrate without significant additional etching of conductive layer material residing within said contact hole, wherein said second etchback is performed using a plasma generated from a source gas comprising SF6 and argon, and wherein said SF6 and argon are present in said source gas at an atomic ratio within a range of about 3:2 to about 12:1.
A method of etching back a conductive material layer within a semiconductor structure, wherein said semiconductor structure comprises a substrate including a conductive region to be connected, a dielectric layer formed over said substrate and defined with a contact hole therein which overlies said conductive region, and a conductive layer deposited within said contact hole, wherein said method comprises the steps of:
- a) a first etchback to remove a portion of said conductive layer;
- b) a buffer step to slow the etch rate of said conductive layer, wherein said buffer step is performed by discontinuing a plasma source power or a substrate bias power or both;
- and
- c) a second etchback to remove residues of said conductive layer from an upper surface of said substrate without significant additional etching of conductive layer material residing within said contact hole wherein a concentration of a fluorine etchant species present in said second etch back is less than a concentration of a fluorine etchant species present in said first etchback.
Dependencies are inferred from the claim text.