Method for forming dual damascene structure

• US 6,268,283 B1
• Filed: 02/09/1999
• Issued: 07/31/2001
• Est. Priority Date: 01/06/1999
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: United Microelectronics Corporation
• Inventors: Huang, Yimin
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): PHAM, THANHHA S
• Application Number:
  US09/248,159
• Time in Patent Office: 903 Days
• Field of Search: 438/623, 438/624, 438/637, 438/638, 438/639, 438/640, 438/634, 438/666, 438/672, 438/622, 438/700, 438/701, 438/702, 438/734, 438/735, 438/736, 438/737, 438/738, 438/740, 438/618
• US Class Current: 438/638
• CPC Class Codes: H01L 21/76808 involving intermediate temporary filling with material

Abstract

An improved method for forming a dual damascene structure is described. A via opening of the dual damascene structure is formed in a dielectric layer. A non-conformal cap layer is then formed on the substrate before the step of defining the photoresist layer. The non-conformal cap layer only covers the top region of the trench but does not fill the trench. A patterned photoresist layer is then formed on the substrate followed by an etching procedure so as to form a trench. The photoresist layer is then removed. The trench and via opening are filled with a conductive layer. Thereafter, redundant portions of the conductive layer are removed by a planarization process.

Claims

1. A method of forming a dual damascene structure in a low-permittivity dielectric layer, comprising:

forming a first low-permittivity dielectric layer on a substrate;

forming an etching stop layer on the first low-permittivity dielectric layer;

forming a second low-permittivity dielectric layer on the etching stop layer;

forming a hard mask layer on the second low-permittivity dielectric layer;

forming a first patterned photoresist layer on the substrate;

removing pairs of the hard mask layer, second low-permittivity dielectric layer, etching stop layer and first low-permittivity dielectric layer to form a opening by using the first patterned photoresist layer as a mask;

removing the first patterned photoresist layer;

forming, a non-conformal cap layer on the hard mask layer to cover the top region of the openings

forming a second patterned photoresist layer on the non-conformal layer;

removing parts of the non-conformal cap layer, hard mask layer and second low-permittivity dielectric layer to form a trench;

removing the second patterned photoresist layer;

removing the non-conformal cap layer; and

filling the opening and trench with a conductive material.

2. The method of claim 1, wherein the first and second low-permittivity dielectric layers includes a spin-on polymer.

3. The method of claim 2, wherein the spin-on polymer is selected from an organic group consisting, of Flare, SILK. Paryiene and PAE-II.

4. The method of claim 1, wherein the step of forming a cap layer includes using a plasma enhanced chemical vapor deposition process.

5. The method of claim 1, wherein the non-conformal cap layer includes a material that can prevent damage from occurring in developing steps of the first and second patterned photoresist layers.

6. The method of claim 5, wherein the material of the non-conformal cap layer includes a silicon oxide, a silicon nitride or a silicon oxynitride layer formed by a plasma enhanced chemical vapor deposition process.

7. The method of claim 1, wherein the step of removing the non-conformal cap layer includes using a dry etching process.

8. A method for manufacturing a dual damascene structure, comprising;

providing a substrate, wherein the substrate further comprises a dielectric layer having an opening;

forming a non-conformal cap layer on a top region of the opening such that the opening is partially filled, wherein the non-conformal cap layer includes a material that can prevent damage from a developer in a following patterning step;

forming a photoresist layer on the non-conformal cap layer;

patterning the photoresist layer to form a patterned photoresist layer;

removing parts of the non-conformal cap layer and the dielectric layer to form a trench by using the patterned photoresist layer as a mask;

removing the patterned photoresist layer;

removing the non-conformal cap layer; and

filling the opening and trench with a conductive layer.

9. The method of claim 8, wherein the dielectric layer includes low-permittivity materials.

10. The method of claim 8, wherein the dielectric layer includes a spin-on polymer.

11. The method of claim 10, wherein the spin-on polymer is selected from the group consisting of Flare, SILK, Parylene and PAE-II.

12. The method of claim 8, wherein the step of forming a cap layer includes using a plasma enhanced chemical vapor deposition process.

13. The method of claim 8, wherein the non-conformal cap layer includes a silicon oxide formed by a plasma enhanced chemical vapor deposition process.

14. The method of claim 8, wherein the non-conformal cap layer includes a silicon nitride formed by a plasma enhanced chemical vapor deposition process.

15. The method of claim 8, wherein the non-conformal cap layer includes a silicon oxynitride formed by a plasma enhanced chemical vapor deposition process.

16. The method of claim 8, wherein the step of removing the non-conformal cap layer includes using a dry etching process.

17. A method for forming an opening, used on a substrate having a dielectric layer with low-permittivity formed thereon, the dielectric layer further comprising a first opening, the method comprising:

forming a non-conformal cap layer on the dielectric layer to cover a top region of the first opening, such that the first opening is partially filled, wherein the non-conformal cap layer includes a material that can prevent damage from a developer in a following patterning step;

forming a photoresist layer on the non-conformal cap layer;

patterning the photoresist layer to form a patterned photoresist layer;

removing parts of the non-conformal cap layer and the dielectric layer to form a second opening; and

removing the patterned photoresist layer.

18. The method of claim 17, wherein the non-conformal cap layer is formed by a plasma enhanced chemical vapor deposition process.