Apparatus and method for electrolytically depositing copper on a semiconductor workpiece

• US 6,932,892 B2
• Filed: 10/27/2003
• Issued: 08/23/2005
• Est. Priority Date: 03/20/1998
• Status: Expired due to Term

• Current Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Original Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Inventors: Taylor, Thomas, Chen, Linlin
• Primary Examiner(s): Ryan, Patrick Joseph
• Assistant Examiner(s): Parsons, Thomas H.
• Application Number:
  US10/695,419
• Publication Number:
  US 20040092065A1
• Time in Patent Office: 666 Days
• Field of Search: 204/224.R, 204/267
• US Class Current: 204/224.00R
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76868 Forming or treating discontinuous thin films, e.g. repair, enhancement or reinforcement of discontinuous thin films
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 2221/1089 Stacks of seed layers
• CPC Class Codes: H05K 3/423 characterised by electroplating method

Abstract

A process for applying a metallization interconnect as to a semiconductor workpiece having a barrier layer deposited on a surface thereof is set forth. The process includes the forming of an ultra-thin metal seed layer on the barrier layer. The ultra-thin seed layer having a thickness of less than or equal to about 500 Angstroms. The ultra-thin seed layer is then enhanced by depositing additional metal thereon to provide an enhanced sed layer. The enhanced seed layer has a thickness at all points on sidewalls of substantially all recessed features distributed within the workpiece that is equal to or greater than about 10% of the nominal seed layer thickness over an exteriorly disposed surface of the workpiece.

Claims

1. A tool for electrochemically depositing copper into submicron miro-recesses on a workpiece having a nonuniform copper seed layer less than 500 Å

thick, the apparatus comprising;

an automated robotic transfer mechanism;

a plurality of electrochemical processing stations arranged about the robot so that the robot can automatically transfer workpieces to/from the processing stations, the processing stations having baths containing a plating solution including copper and workpiece holders, and the processing stations being configured to operate in a seed layer enhancement mode in which additional copper is electrochemically deposited onto the workpiece to enhance the seed layer for filling the recesses and a bulk plating mode in which copper is electroplated onto the workpiece until the recesses are filled.

2. The apparatus of claim 1, wherein the electrochemical processing stations include a first processing station configured to operate in the seed layer enhancement mode and a second processing station configured to operate in the bulk plating mode.

3. The apparatus of claim 1 wherein the first electrochemical processing station comprises a first workpiece holder having first electrical contacts and a first bath comprising an alkaline plating solution, and the second electrochemical processing station comprises a second workpiece holder having second electrical contacts and a second bath comprising an acidic plating solution.

4. The apparatus of claim 1, wherein the electrochemical processing stations include at least one processing station that can operate in the enhancement mode to enhance the seed layer and then operate in the bulk plating mode to fill the recesses.

5. The apparatus of claim 1 wherein the electrochemical processing stations include at least one processing station that operates in the enhancement mode by electroplating additional material onto the seed layer.