Electrodeposition apparatus with virtual anode

• US RE37,749 E1
• Filed: 03/02/2000
• Issued: 06/18/2002
• Est. Priority Date: 08/01/1990
• Status: Expired due to Term

• Current Assignee: Jaime Poris
• Original Assignee: Jaime Poris
• Inventors: Poris, Jaime
• Primary Examiner(s): Mayekar, Kishor
• Application Number:
  US09/517,400
• Time in Patent Office: 838 Days
• Field of Search: 204/231, 204/297.R, 204/224.R
• US Class Current: 204/230.1
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 21/76885 By forming conductive members before deposition of protective insulating material, e.g. pillars, studs

Abstract

An electrochemical etching step in a semiconductor device fabrication process increases the radius of curvature of edges of metal lines deposited on the semiconductor device. The metal lines are fabricated by forming a mask, electrodepositing the metal, and removing the mask, and the electro-chemical etching step in performed subsequently. The increased radius of curvature of the metal lines simplifies subsequent planarization and decreases line-to-line capacitance, thereby enhancing device performance. In an apparatus for performing the fabrication process, wires sown into a gasket which secures the semiconductor wafer and prevents electrolyte leakage, allows the gasket to function also as a component of the cathode. A more uniform metal deposition is created by a virtual anode, i.e., a metal plate having an aperture and being located between the anode and the cathode.

Claims

1. Apparatus for electrodeposition of a conducting metal onto a semiconductor, said apparatus comprising:

diffusion barrier deposition process means to provide a diffusion barrier layer on said semiconductor having contacts and vias, and to prevent metal diffusion into said semiconductor,

an electrically conducting nucleation layer deposition process means to provide an electrically conducting nucleation layer on said diffusion barrier layer and a sufficient adhesion surface for electrodeposition of said metal,

inert metal mask process means to place a first metal mask layer onto said nucleation layer,

selective electrodeposition process means to selectively electrodeposit said metal onto said nucleation layer while simultaneously completely filling a contact or via,

electrochemical etching means to increase a radius of curvature of edges of said metal, thereby facilitating planarization and decreasing line-to-line capacitance, and

a virtual anode disposed between a cathode and an anode for improving primary current distribution to improve uniformity in a thickness of said metal electrodeposited on said semiconductor.

2. The apparatus as in claim 1 further including a virtual anode gasket adapted to prevent electrolyte leakage.

3. An apparatus for electrodeposition of metal onto a semiconductor having an electrically conducting layer, comprising:

an anode,

a cathode wire,

a cell body,

a anode gasket for sealing said anode to said cell body adapted to prevent leakage of an electrolyte,

a cathode gasket for sealing said semiconductor to said cell body adapted to prevent leakage of said electrolyte and providing contact between said cathode wire and said electrically conducting layer,

means for securing said semiconductor to said cathode gasket to exclude said electrolyte from contacting said cathode wire,

means for exposing a selected area of said semiconductor to said electrolyte,

a virtual anode located between said anode and said electrically conducting layer for creating a more uniform current distribution to said electrically conducting layer, and

a virtual anode gasket for sealing said virtual anode to said cell body to adapted to prevent leakage of said electrolyte.

4. The apparatus of claim 3 wherein said cathode gasket is configured to expose an area of a flat substrate to said electrolyte.

5. The apparatus of claim 4 wherein said area is within a perimeter of said gasket.

6. The apparatus of claim 3 wherein an aperture in said virtual anode is located on an axis substantially between a first center point of a flat substrate and a second center point of said anode.

7. The apparatus of claim 3 further comprising a plurality of metal regions adapted to make electrical contact with the electrically conducting layer, thereby creating acceptable ohmic contact between said metal regions and the electrically conducting layer, the acceptable ohmic contact being ascertainable by a resistance check across any pair of said metal regions when said electrolyte is absent.