Depositing material into high aspect ratio structures

Patent metadata

Field	Value
Publication number	US-9384982-B2
Application number	US-201314758043-A
Country	US
Kind code	B2
Filing date	Dec 30, 2013
Priority date	Dec 31, 2012
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A method is provided, along with a corresponding apparatus, for filling a high aspect ratio hole without voids or for producing high aspect ratio structures without voids. A beam having a diameter smaller than the diameter of the hole is directed into the hole to induced deposition beginning in the center region of the hole bottom. After an elongated structure is formed in the hole by the beam-induced deposition, a beam can then be scanned in a pattern at least as large as the hole diameter to fill the remainder of the hole. The high aspect ratio hole can then be cross-sectioned using an ion beam for observation without creating artefacts. When electron-beam-induced deposition is used, the electrons preferably have a high energy to reach the bottom of the hole, and the beam has a low current, to reduce spurious deposition by beam tails.

First claim

We claim as follows:

1. A method of filling a hole using charged particle beam-induced deposition, comprising:
providing a deposition precursor gas at the surface of the work piece;
directing a charged particle beam into a hole having an aspect ratio greater than 3:1, the charged particle beam being directed to a region within the hole having an area less than the cross sectional area of the hole to decompose the precursor gas and deposit material in the hole, the charged particle beam being directed into the hole for a sufficient period of time to form an elongate structure that does not touch the side walls at the top of the hole.

2. The method of claim 1 in which further comprising directing the charged particle beam to cover an area extended beyond the edges of the hole to fill the region between the elongate structure and the hole side walls, thereby filling the hole without voids in the fill material.

3. The method of claim 1 in which directing the charge particle beam into the hole for a sufficient period of time to form an elongate structure comprises forming an elongate structure that does not contact the top walls of the hole, and further comprising directing the charged particle to an area that is a superset of the first area to finish filling the hole.

4. The method of claim 1 in which the hole comprises a cylindrical hole and in which directing the charged particle beam into the hole comprises directing an electron beam in a circular pattern, the diameter of the circular pattern being less than ½ the diameter of the hole.

5. The method of claim 1 in which the hole is a channel and in which directing the charged particle beam into the hole comprises directing an electron beam into the channel in a circular pattern having a diameter of less than ½ the channel width.

6. A method of filling a high aspect ratio hole, comprising:
providing a deposition precursor gas at the surface of a work piece, the work piece having at least one high aspect ratio hole;
directing an electron beam into the high aspect ratio hole, the electron beam being directed in first pattern to impact a region in the hole having a cross section area less than the entire cross sectional area of the hole to deposit an elongate structure into the hole;
directing an electron beam toward the work piece in a second pattern to fill the regions of the hole between the elongate structure and the hole side wall, to fill the hole without leaving voids in the fill material.

7. The method of claim 6 , in which directing an electron beam toward the work piece in a second pattern includes directing the electron beam in a second pattern covering an area that includes the entire hole.

8. The method of claim 6 , in which:
providing a deposition precursor gas at the surface of a substrate includes providing a precursor gas that decomposes in the presence of the electron beam to deposit a metal; and
directing an electron beam in the first pattern includes directing an electron beam having a landing energy of greater than 5000 eV.

9. The method of claim 6 , in which:
providing a deposition precursor gas at the surface of a substrate includes providing a precursor gas that decomposes in the presence of the electron beam to deposit carbon; and
directing an electron beam in the first pattern includes directing an electron beam having a landing energy of greater than 3000 eV.

10. The method of claim 6 , in which directing an electron beam in the first pattern includes directing the electron beam in a circular pattern, the diameter of the circle pattern being less than ½ the diameter of the hole.

11. The method of claim 6 , in which directing an electron beam in the first pattern includes directing the electron beam in a circular pattern, the diameter of the circle pattern being less than ¼ the diameter of the hole.

12. The method of claim 10 in which the hole is a channel and the diameter of the circle pattern is less than ½ the channel width.

13. The method of claim 11 in which the hole is a channel and the diameter of the circle pattern is less than ¼ the channel width.

14. A method of filling a high aspect ratio hole, comprising:
providing a deposition precursor gas at the surface of a work piece, the work piece having at least one high aspect ratio hole;
directing an electron beam having a landing energy greater than 5000 eV into the high aspect ratio hole, the electron beam being directed in circular pattern within the hole, the radius of the circular pattern being less than ¼ the radius of the hole to deposit an elongate structure into the hole;
directing an electron beam toward the work piece in a second pattern to fill the regions of the hole between the elongate structure and the hole side wall, to fill the hole without leaving voids in the fill material.

15. A charged particle beam system comprising:
a source of charged particles;
a focusing column for directing a beam of charged particles toward a work piece, the work piece having at least one hole having an aspect ratio greater than 3:1;
a gas delivery system for providing a precursor gas at the surface of the work piece; and
a system controller programmed with instructions to control the charged particle microscope for:
directing the charged particle beam into the hole, the charged particle beam being directed to a region within the hole having an area less than the cross sectional area of the hole to decompose the precursor gas and deposit material in the hole, the charged particle beam being directed into the hole for a sufficient period of time to form an elongate structure that does not touch the side walls at the top of the hole.

16. The charged particle beam system of claim 15 in which the instructions further comprise directing the charged particle beam to cover an area extended beyond the edges of the hole to fill the region between the elongate structure and the hole side walls, thereby filling the hole without voids in the fill material.

17. The charged particle beam system of claim 15 in which the instructions for directing the charged particle beam into the hole for a sufficient period of time to form an elongate structure comprises instructions for forming an elongate structure that does not contact the top walls of the hole, and further comprising directing the charged particle to an area that is a superset of the first area to finish filling the hole.

18. The charged particle beam system of claim 15 in which the hole comprises a cylindrical hole and in which directing the charged particle beam into the hole comprises directing an electron beam in a circular pattern, the diameter of the circular pattern being less than ½ the diameter of the hole.

19. The charged particle beam system of claim 15 in which the hole is a channel and in which directing the charged particle beam into the hole comprises directing an electron beam into the channel in a circular pattern having a diameter of less than ½ the channel width.

Assignees

• Fei Co

Inventors

• Lee Sang Hoon
• Blackwood Jeffrey
• Stone Stacey

Classifications

• H10W20/0261

  characterised by the filling method or the material of the conductive fill · CPC title

• H10P14/2925

  Surface structures · CPC title

• H10P14/27

  using selective deposition, e.g. simultaneous growth of monocrystalline and non-monocrystalline semiconductor materials · CPC title

• H10P14/6902

  composed of carbon, e.g. alpha-C, diamond or hydrogen doped carbon · CPC title

• H10P14/6338

  the reactions being activated by other means than plasma or thermal, e.g. photo-CVD · CPC title