Method of aligning nanotubes and wires with an etched feature

• US 7,575,693 B2
• Filed: 12/14/2005
• Issued: 08/18/2009
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: Nantero Incorporated
• Original Assignee: Nantero Incorporated
• Inventors: Konsek, Steven L., Bertin, Claude L., Rueckes, Thomas, Meinhold, Mitchell, Yates, Colin D.
• Primary Examiner(s): Tran; Binh X
• Application Number:
  US11/304,801
• Publication Number:
  US 20060264053A1
• Time in Patent Office: 1,343 Days
• Field of Search: 216/75, 216/77, 216/89, 216/102, 977/742
• US Class Current: 216/75
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76885 By forming conductive members before deposition of protective insulating material, e.g. pillars, studs
• CPC Class Codes: H01L 2221/1094 Conducting structures comprising nanotubes or nanowires
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs

Abstract

A method of forming an aligned connection between a nanotube layer and an etched feature is disclosed. An etched feature is formed having a top and a side and optionally a notched feature at the top. A patterned nanotube layer is formed such that the nanotube layer contacts portions of the side and overlaps a portion of the top of the etched feature. The nanotube layer is then covered with an insulating layer. Then a top portion of the insulating layer is removed to expose a top portion of the etched feature.

Claims

1. A method of forming a nanotube electrical connection aligned to an etched feature comprising a metal layer, the method comprising:

providing a substrate;

forming an etched feature on the substrate, wherein the etched feature comprises a raised metal layer on the substrate, the metal layer having a top and a side;

depositing and patterning the nanotube layer such that the nanotube layer contacts a portion of the side of the metal layer and overlaps a portion of the top of the metal layer;

forming an insulating layer that covers the nanotube layer; and

removing a top portion of the insulating layer to expose a top portion of the metal layer and removing the nanotube layer from on top of the metal layer leaving the nanotube layer in contact with the metal layer.

2. The method of claim 1 wherein forming the raised metal layer comprises forming the raised metal layer using an anisotropic process.

3. The method of claim 1 wherein forming the raised metal layer comprises forming the metal layer having side portion with a sloped profile;

and

wherein depositing and patterning a nanotube layer includes depositing a portion of the nanotube layer so that it contacts the sloped side portion and overlaps a portion of the top of the metal layer.

4. The method of claim 1 wherein removing a top portion of the insulating layer is accomplished using chemical mechanical polishing.

5. The method of claim 1 wherein removing a top portion of the insulating layer is accomplished using etching.

6. The method of claim 1 wherein the raised metal layer is formed by:

photomasking the substrate to define a mask pattern on the metal layer;

first isotropic etching the metal layer such that some of the etch undercuts the mask pattern and extends under edges of the mask pattern to remove a portion of the top surface of the metal layer forming a notched feature on the metal layer;

second anisotropic etching to complete the formation of the raised metal layer; and

removing the photomask pattern;

and wherein depositing and patterning a nanotube layer includes forming a nanotube layer such that the nanotube layer contacts portions of the side of the metal layer, the notched portion of the metal layer, and overlaps a portion of the top of the metal layer; and

wherein removing a top portion of the insulating layer exposes a top portion of the metal layer, removes the nanotube layer from on top of the metal layer, and leaves a portion of the nanotube layer overlapping a portion of the metal layer in the region defined by the notched feature, thereby insuring the nanotube layer remains in contact with the metal layer.

7. The method of claim 6 wherein the first isotropic etching is conducted so that the notched feature extends downward no more than half of the height of the metal layer.

8. The method of claim 1 wherein the raised metal layer is formed by:

photomasking the substrate to define a mask pattern on the metal layer;

first anisotropically etching the metal layer such that some of the etch undercuts the mask pattern and extends under edges of the mask pattern to remove a portion of the top surface of the metal layer;

narrowing the line width of portions of the photomask mask pattern to expose portions metal layer;

second anisotropically etching of the metal layer to define the raised metal layer having a notched feature on the top of the metal layer; and

removing the photomask pattern;

and wherein depositing and patterning a nanotube layer includes forming a nanotube layer such that the nanotube layer contacts portions of the side of the metal layer, the notched portion of the metal layer, and overlaps a portion of the top of the metal layer; and

wherein removing a top portion of the insulating layer exposes a top portion of the metal layer, removes the nanotube layer from on top of the metal layer, and leaves a portion of the nanotube layer overlapping a portion of the metal layer in the region defined by the notched feature, thereby insuring the nanotube layer remains in contact with the metal layer.

9. The method of claim 8 wherein the first anisotropic etching is conducted so that the notched feature extends downward no more than half of the height of the metal layer.

10. The method of claim 9 wherein the second anisotropic etching is conducted to etch the metal layer a remaining distance down to the substrate.

11. The method of claim 1 wherein forming the raised metal layer comprises depositing metal-containing materials on the substrate.

12. The method of claim 11 wherein depositing metal-containing materials comprises depositing a layer of material selected from among aluminum, tungsten, tantalum, and titanium.

13. The method of claim 11 wherein depositing metal-containing materials comprises depositing metal alloys.

14. The method of claim 11 wherein depositing metal-containing materials comprises depositing metal nitrides.

15. The method of claim 11 wherein depositing metal-containing materials comprises depositing more than one layer of metal-containing material.

16. A method of forming a nanotube connection aligned to an etched feature, the method comprising:

providing a substrate;

forming an etched feature on the substrate, the etched feature including a top surface and a side surface;

depositing and patterning a nanotube layer such that the nanotube layer forms a nanotube ribbon that contacts the side and top surfaces of the etched feature;

forming an insulating layer that covers the nanotube ribbon and the etched feature; and

processing the substrate to remove a top portion of the insulating layer to expose the top portion of the etched feature while also removing the nanotube ribbon from the top of the etched feature while leaving an insulated nanotube ribbon in contact with the side surface of the etched feature.