System for electrochemically processing a workpiece

Abstract

A reactor for electrochemically processing at least one surface of a microelectronic workpiece is set forth. The reactor comprises a reactor head including a workpiece support that has one or more electrical contacts positioned to make electrical contact with the microelectronic workpiece. The reactor also includes a processing container having a plurality of nozzles angularly disposed in a sidewall of a principal fluid flow chamber at a level within the principal fluid flow chamber below a surface of a bath of processing fluid normally contained therein during electrochemical processing. A plurality of anodes are disposed at different elevations in the principal fluid flow chamber so as to place them at difference distances from a microelectronic workpiece under process without an intermediate diffuser between the plurality of anodes and the microelectronic workpiece under process. One or more of the plurality of anodes may be in close proximity to the workpiece under process. Still further, one or more of the plurality of anodes may be a virtual anode. The present invention also related to multi-level anode configurations within a principal fluid flow chamber and methods of using the same.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation of prior International Application No. PCT / US00 / 10120, filed on Apr. 13, 2000 in the English language and published in the English language as International Publication No. WO00 / 61498, which in turn claims priority to the following three U.S. Provisional Applications: U.S. Ser. No. 60 / 129,055, entitled “WORKPIECE PROCESSOR HAVING IMPROVED PROCESSING CHAMBER”, filed Apr. 13, 1999; U.S. Ser. No. 60 / 143,769, entitled “WORKPIECE PROCESSING HAVING IMPROVED PROCESSING CHAMBER”, filed Jul. 12, 1999; U.S. Ser. No. 60 / 182,160 entitled “WORKPIECE PROCESSOR HAVING IMPROVED PROCESSING CHAMBER”, filed Feb. 14, 2000. The entire disclosures of all three of the prior applications, as well as International Publication No. WO00 / 61498, are incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] The fabrication of micr...

AI Technical Summary

Benefits of technology

"The patent describes a reactor for electrochemically processing microelectronic workpieces. The reactor has a workpiece support with electrical contacts and a processing container with nozzles. The nozzles are positioned in a sidewall of a fluid flow chamber below the surface of the bath of processing fluid. The reactor also has multiple anodes at different elevations in the chamber, without an intermediate diffuser between them and the workpiece. The anodes can be close to the workpiece or virtual anodes. The patent also describes multi-level anode configurations and methods of using them. The technical effects of the invention include improved surface processing of microelectronic workpieces through electrochemical means."

Problems solved by technology

Restricting the electroplating solution to the appropriate portions of the workpiece, however, is often problematic.

Additionally, ensuring proper mass transfer conditions between the electroplating solution and the surface of the workpiece can be difficult.

Absent such mass transfer control, the electrochemical processing of the workpiece surface can often be non-uniform.

This can be particularly problematic in connection with the electroplating of metals.

Although substantial improvements in diffusion layer control result from the use of a diffuser, such control is limited.

The present inventors have found that these localized areas of increased flow velocity at the surface of the workpiece affect the diffusion layer conditions and can result in non-uniform deposition of the electroplated material over the surface of the workpiece.

Diffuser hole pattern configurations also affect the distribution of the electric field since the diffuser is disposed between the anode and workpiece, and can result in non-uniform deposition of the electroplated material.

Another problem often encountered in electroplating is disruption of the diffusion layer due to the entrapment and evolvement of gasses during the electroplating process.

They also erode into the plating solution changing the dimensional tolerances.

Ultimately, they must be replaced thereby increasing the amount of maintenance required to keep the tool operational when compared to tools using inert anodes.

Another challenge associated with the plating of uniform films is the changing resistance of the plated film.

The changing resistance makes it difficult for a given set of chamber hardware to yield optimal uniformity on a variety of seed layers and deposited film thicknesses.

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