Ion beam etching system

Patent metadata

Field	Value
Publication number	US-9257295-B2
Application number	US-201514637260-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Jul 8, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

The disclosed embodiments relate to methods and apparatus for removing material from a substrate. In various implementations, conductive material is removed from a sidewall of a previously etched feature such as a trench, hole or pillar on a semiconductor substrate. In practicing the techniques herein, a substrate is provided in a reaction chamber that is divided into an upper plasma generation chamber and a lower processing chamber by a corrugated ion extractor plate with apertures therethrough. The extractor plate is corrugated such that the plasma sheath follows the shape of the extractor plate, such that ions enter the lower processing chamber at an angle relative to the substrate. As such, during processing, ions are able to penetrate into previously etched features and strike the substrate on the sidewalls of such features. Through this mechanism, the material on the sidewalls of the features may be removed.

First claim

What is claimed is:

1. A method of removing material from sidewalls of features in partially fabricated semiconductor device structures, comprising:
(a) receiving a substrate in a reaction chamber, wherein the reaction chamber is divided into a plasma generation sub-chamber and a processing sub-chamber by an ion extractor plate, wherein at least a portion of the ion extractor plate is corrugated, and wherein the ion extractor plate comprises apertures designed or configured to permit the passage of ions therethrough;
(b) flowing a plasma generating gas into and generating a plasma in the plasma generation sub-chamber; and
(c) accelerating ions from the plasma generation chamber, through the ion extractor plate, and into the processing volume toward the substrate to thereby remove material from feature sidewalls.

2. The method of claim 1 , wherein the features of the semiconductor device structure comprise an etched insulating layer positioned between two etched conductive layers.

3. The method of claim 1 , wherein at least some of the apertures have a central axis that is oriented at a non-perpendicular angle relative to the substrate.

4. The method of claim 1 , wherein substantially no plasma is present in the processing sub-chamber during processing.

5. The method of claim 1 , further comprising rotating the ion extractor plate during processing, but less than or equal to 360° in a single direction.

6. The method of claim 5 , wherein the ion extractor plate comprises a plurality of distinct segment types, and wherein the ion extractor plate is rotated to an extent at which local parts of the substrate are exposed ions originating from each of the plurality of distinct segment types.

7. The method of claim 5 , wherein the ion extractor plate is rotated clockwise and counter-clockwise while removing the material from feature sidewalls.

8. The method of claim 1 , wherein the substrate holder is stationary during processing.

9. The method of claim 1 , further comprising moving the ion extractor plate along an axis extending through the center of the extractor plate and substrate.

10. The method of claim 9 , wherein moving the ion extractor plate along the axis extending through the center of the extractor plate and substrate occurs during an etching operation.

11. The method of claim 9 , wherein moving the ion extractor plate along the axis extending through the center of the extractor plate and substrate occurs between etching steps in a multi-step etching process.

12. The method of claim 9 wherein moving the ion extractor plate along the axis extending through the center of the extractor plate and substrate occurs after processing the substrate and before processing a second substrate.

13. The method of claim 1 , further comprising moving the ion extractor plate in a direction parallel to the substrate.

14. The method of claim 1 , further comprising etching the features in the substrate prior to (a).

15. The method of claim 14 , further comprising moving the substrate from an apparatus where the etching is performed to the reaction chamber prior to (a).

16. The method of claim 1 , further comprising applying a bias to the ion extractor plate.

17. The method of claim 16 , wherein the reaction chamber further comprises RF straps connecting the ion extractor plate with a substrate support used to support the substrate in the reaction chamber, the RF straps designed or configured to provide a bias on the substrate support that corresponds to the bias applied to the ion extractor plate.

18. The method of claim 1 , wherein the apertures are designed or configured to direct the passage of ions therethrough at a plurality of angles with respect to the substrate.

19. The method of claim 1 , wherein the features comprise trenches and/or holes.

20. The method of claim 1 , wherein the features comprise pillars.

Assignees

• Lam Res Corp

Inventors

• Singh Harmeet
• Paterson Alex

Classifications

• H10P70/20

  Cleaning during device manufacture · CPC title

• H10P72/0421

  for drying etching · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P50/267

  using plasmas · CPC title

• H10P50/242

  of Group IV materials · CPC title