Methods for forming nano-gap electrodes for use in nanosensors

• US 10,438,811 B1
• Filed: 04/15/2015
• Issued: 10/08/2019
• Est. Priority Date: 04/15/2014
• Status: Active Grant

• Current Assignee: Quantum Biosystems Inc.
• Original Assignee: Quantum Biosystems Inc.
• Inventors: Ikeda, Shuji
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): Kolahdouzan, Hajar
• Application Number:
  US14/687,856
• Time in Patent Office: 1,637 Days
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: C12Q 1/6869 Methods for sequencing
• CPC Class Codes: G01N 33/48721 Investigating individual macromolecules, e.g. by translocation through nanopores Coulter counters in general G01N15/12; fabrication methods for nanoscale apertures B81B1/00; sequencing of nucleic acids C12Q1/68
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence
• CPC Class Codes: H01L 21/31138 by dry-etching

Abstract

Methods for forming electrodes for use in nano-gap electrodes are provided. Such methods can be used to form electrodes for use in devices that can be used to sense or detect biomolecules, such as in biomolecule sequence applications.

Claims

1. A method for forming a metallic material adjacent to a substrate for use in a nano-gap electrode, comprising:

(a) forming a single layer of a hard mask material adjacent to said substrate, wherein said hard mask is not a photoresist;

(b) etching said single layer of said hard mask material to form a first hole in said layer;

(c) etching said single layer of said hard mask material to (i) form at least one second hole in said single layer of said hard mask material and (ii) remove said hard mask material in said first hole to expose said substrate, wherein said at least one second hole is adjacent to said first hole, and wherein said at least one second hole extends partially through said single layer;

(d) depositing said metallic material over said substrate and over a portion of said single layer of said hard mask material; and

(e) removing said single layer of said hard mask material to provide said metallic material adjacent to said substrate.

2. The method of claim 1, wherein said substrate includes at least a first layer and a second layer.

3. The method of claim 2, wherein said first layer is a semiconductor.

4. The method of claim 3, wherein said semiconductor includes silicon.

5. The method of claim 2, wherein said second layer is a semiconductor nitride.

6. The method of claim 1, wherein said hard mask material is tetraethyl orthosilicate.

7. The method of claim 1, wherein subsequent to said etching in (b) and before said etching in (c), said first hole extends partially through said single layer of said hard mask material.

8. The method of claim 1, wherein said etching in (b) is anisotropic etching.

9. The method of claim 8, wherein said anisotropic etching includes resistive ion etching.

10. The method of claim 1, wherein said etching in (c) is isotropic etching.

11. The method of claim 1, wherein said at least one second hole includes a plurality of holes.

12. The method of claim 11, wherein individual holes of said plurality have a diameter that is less than or equal to (2)^1/2*L/2 or L/(3)^1/2, wherein ‘

L’

is a distance between centers of holes in said plurality.

13. The method of claim 11, wherein individual holes of said plurality have a diameter that is greater than (2)^1/2*L/2 or L/(3)^1/2, wherein ‘

L’

is a distance between centers of holes in said plurality.

14. The method of claim 1, said removing in (e) includes removing said single layer below said metallic material at a time that is substantially the same as removing a lateral portion of said single layer.

15. The method of claim 1, wherein said metallic material comprises gold, silver or platinum.

16. The method of claim 1, wherein said removing in (e) includes removing said metallic material adjacent to said layer.

17. The method of claim 1, wherein said at least one second hole is horizontally adjacent to said first hole.