MULTI-LAYER PATTERN FOR ALTERNATE ALD PROCESSES

• US 20130084688A1
• Filed: 09/30/2011
• Published: 04/04/2013
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: O'Meara, David L., Mosden, Aelan
• Granted Patent: US 8,809,169 B2
• Time in Patent Office: Days
• US Class Current: 438/478
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/0338 Process specially adapted to improve the resolution of the mask

Abstract

A method of patterning a substrate. A sacrificial film is formed over a substrate and a pattern created therein. A first spacer layer is conformally deposited over the patterned sacrificial film and at least one horizontal portion of the first spacer layer is removed while vertical portions of the first spacer layer remain. A second spacer layer is conformally deposited over the patterned sacrificial film and the remaining portions of the first spacer layer. At least one horizontal portion of the second spacer layer is removed while vertical portions of the second spacer layer remain. Conformal deposition of the first and second spacer layers is optionally repeated one or more times. Conformal deposition of the first layer is optionally repeated. Then, one of the first or second spacer layers is removed while substantially leaving the vertical portions of the remaining one of the first or second spacer layers.

Claims

1. A method of patterning a substrate, the method comprising:

a) forming a sacrificial film over a substrate;

b) creating a pattern in the sacrificial film;

c) sequentially first, conformally depositing a first spacer layer over the patterned sacrificial film, and second, removing at least one horizontal portion of the first spacer layer while substantially leaving vertical portions of the first spacer layer;

d) sequentially first, conformally depositing a second spacer layer over the patterned sacrificial film and the remaining portions of the first spacer layer, and second, removing at least one horizontal portion of the second spacer layer while substantially leaving vertical portions of the second spacer layer;

e) optionally repeating c) and d) one or more times;

f) optionally repeating c); and

g) removing one of the first or second spacer layers while substantially leaving the vertical portions of the remaining one of the first or second spacer layers.

2. The method of claim 1 further comprising:

removing the sacrificial film before conformally depositing the second spacer layer.

3. The method of claim 1 further comprising:

removing the sacrificial film before removing one of the first or second spacer layers.

4. The method of claim 1, wherein forming a pattern in the sacrificial film further comprises:

depositing, imaging, and developing a photo-resist layer;

etching the sacrificial film in accordance with the imaged photo-resist layer; and

removing the photo-resist layer.

5. The method of claim 1, wherein conformally depositing the first spacer layer includes a chemical vapor deposition process, a plasma-enhanced chemical vapor deposition process, an atomic layer deposition process, or a plasma-enhanced atomic layer deposition process.

6. The method of claim 5, wherein the first spacer layer comprises silicon dioxide, silicon nitride, or a high-k material.

7. The method of claim 1, wherein conformally depositing the second spacer layer includes an atomic layer deposition process, or a plasma-enhanced atomic layer deposition process.

8. The method of claim 7, wherein the second spacer layer comprises silicon nitride, silicon oxide, or a high-k material.

9. The method of claim 1, wherein removing at least one horizontal portion of the first and second spacer layers includes removing a horizontal portion over a top surface of the sacrificial film.

10. The method of claim 9, wherein removing the horizontal portion over the top surface of the sacrificial film further comprises a planarization process.

11. The method of claim 1, wherein removing at least one horizontal portion of the first and second spacer layers includes removing a horizontal portion over a top surface of the sacrificial film and a horizontal portion over a top surface of the substrate.

12. The method of claim 11, wherein removing the horizontal portions over the top surfaces of the sacrificial film and the substrate further comprises an etching process.

13. The method of claim 1, wherein a thin film is formed between the substrate and the sacrificial film, the method further comprising:

h) using the vertical portions of the remaining one of the first or second spacer layers as a mask to etch the thin film.

14. The method of claim 1 further comprising:

h) selectively forming an epitaxial layer over the substrate; and

i) removing the vertical portions of the remaining one of the first or second spacer layers to form at least one feature in the epitaxial layer.

15. A method of patterning a substrate, the method comprising:

a) forming a sacrificial film over a substrate;

b) creating a pattern in the sacrificial film;

c) sequentially first, conformally depositing a first spacer layer over the substrate and the patterned first sacrificial film, and second, removing at least one horizontal portion of the first spacer layer while substantially leaving vertical portions of the first spacer layer;

d) removing portions of the sacrificial film not overlaid by the remaining portions of the first spacer layer;

e) sequentially first, conformally depositing a second spacer layer over the remaining portions of the sacrificial film and the remaining portions of the first spacer layer pattern, and second, removing at least one horizontal portion of the second spacer layer while substantially leaving vertical portions of the second spacer layer;

f) sequentially first, conformally depositing a third spacer layer over the remaining portions of the first spacer layer, the remaining portions of the second spacer layer, and the remaining portions of the sacrificial film, and second, removing at least one horizontal portion of the third spacer layer while substantially leaving vertical portions of the third spacer layer;

g) optionally repeating e) and f) one or more times;

h) optionally repeating e); and

i) removing portions of the first and third spacer layers not overlaid by the second spacer layer.

16. The method of claim 15, wherein conformally depositing the first spacer layer includes a chemical vapor deposition process, a plasma-enhanced chemical vapor deposition process, an atomic layer deposition process, or a plasma-enhanced atomic layer deposition process.

17. The method of claim 15, wherein conformally depositing the second spacer layer or the third spacer layer includes an atomic layer deposition process, or a plasma-enhanced atomic layer deposition process.

18. The method of claim 15 further comprising:

j) selectively forming an epitaxial layer over the substrate; and

k) removing the second spacer layer to form at least one feature in the epitaxial layer.

19. The method of claim 15, wherein the first spacer layer and the third spacer layer comprise the same spacer material.

20. The method of claim 15, wherein the first spacer layer has a first thickness, the second spacer layer has a second thickness, and the third spacer layer has a third thickness, the first thickness being greater than the second and third thicknesses.

21. A method of patterning a substrate, the method comprising:

a) forming a sacrificial film over a substrate;

b) creating a pattern in the sacrificial film;

c) sequentially first, conformally depositing a first spacer layer over the patterned sacrificial film, and second, removing at least one horizontal portion of the first spacer layer while substantially leaving vertical portions of the first spacer layer;

d) sequentially first, conformally depositing a second spacer layer over the patterned sacrificial film and the remaining portions of the first spacer layer, and second, removing at least one horizontal portion of the second spacer layer while substantially leaving vertical portions of the second spacer layer;

e) optionally repeating c) and d) one or more times;

f) optionally repeating c);

g) removing the sacrificial film;

h) removing one of the first or second spacer layers;

i) selectively forming an epitaxial layer over the substrate; and

j) removing the remaining one of the first and second spacer layers to form at least one feature in the epitaxial layer.

22. The method of claim 21, wherein the epitaxial layer comprises silicon, doped silicon, graded-silicon, SiGe, or graded SiGe.