Wet etching methods for copper removal and planarization in semiconductor processing
First Claim
1. An apparatus for wet chemical etching comprising:
- (a) a substrate holder configured to hold and rotate a semiconductor substrate;
(b) a first nozzle configured to apply a liquid etchant to a working surface of the semiconductor substrate, wherein the first nozzle is configured to be radially movable during treatment of the semiconductor substrate;
(c) a second nozzle configured to apply a liquid quenchant to the surface of the semiconductor substrate, wherein the first nozzle and the second nozzle are proximate to each other during treatment of the semiconductor substrate, wherein the second nozzle is configured to be radially movable during treatment of the semiconductor substrate, and wherein the second nozzle is configured to be positioned at a more radially outward location than the first nozzle during treatment of the semiconductor substrate, and(d) a chemical wet etch endpoint detector,wherein the apparatus is configured to establish a treating area said treating area less than the total area of the working surface of the semiconductor substrate and comprising that portion of the semiconductor substrate contacted by the liquid etchant but not also contacted by the liquid quenchant.
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Abstract
Exposed copper regions on a semiconductor substrate can be etched by a wet etching solution comprising (i) one or more complexing agents selected from the group consisting of bidentate, tridentate, and quadridentate complexing agents; and (ii) an oxidizer, at a pH of between about 5 and 12. In many embodiments, the etching is substantially isotropic and occurs without visible formation of insoluble species on the surface of copper. The etching is useful in a number of processes in semiconductor fabrication, including for partial or complete removal of copper overburden, for planarization of copper surfaces, and for forming recesses in copper-filled damascene features. Examples of suitable etching solutions include solutions comprising a diamine (e.g., ethylenediamine) and/or a triamine (e.g., diethylenetriamine) as bidentate and tridentate complexing agents respectively and hydrogen peroxide as an oxidizer. In some embodiments, the etching solutions further include pH adjustors, such as sulfuric acid, aminoacids, and carboxylic acids.
152 Citations
17 Claims
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1. An apparatus for wet chemical etching comprising:
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(a) a substrate holder configured to hold and rotate a semiconductor substrate; (b) a first nozzle configured to apply a liquid etchant to a working surface of the semiconductor substrate, wherein the first nozzle is configured to be radially movable during treatment of the semiconductor substrate; (c) a second nozzle configured to apply a liquid quenchant to the surface of the semiconductor substrate, wherein the first nozzle and the second nozzle are proximate to each other during treatment of the semiconductor substrate, wherein the second nozzle is configured to be radially movable during treatment of the semiconductor substrate, and wherein the second nozzle is configured to be positioned at a more radially outward location than the first nozzle during treatment of the semiconductor substrate, and (d) a chemical wet etch endpoint detector, wherein the apparatus is configured to establish a treating area said treating area less than the total area of the working surface of the semiconductor substrate and comprising that portion of the semiconductor substrate contacted by the liquid etchant but not also contacted by the liquid quenchant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification