Low dielectric constant shallow trench isolation

• US 6,770,537 B2
• Filed: 06/27/2002
• Issued: 08/03/2004
• Est. Priority Date: 02/14/2000
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farrar, Paul A.
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): Owens, Beth E.
• Application Number:
  US10/184,592
• Publication Number:
  US 20020164859A1
• Time in Patent Office: 768 Days
• Field of Search: 438/296, 438/421, 438/411, 438/412, 438/294
• US Class Current: 438/296
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264

Abstract

Techniques of shallow trench isolation and devices produced therefrom are provided. The techniques of shallow trench isolation utilize foamed polymers, cured aerogels or air gaps as the insulation medium. Such techniques facilitate lower dielectric constants than the standard silicon dioxide due to the cells of gaseous components inherent in foamed polymers, cured aerogels or air gaps. Lower dielectric constants reduce capacitive coupling concerns and thus permit higher device density in an integrated circuit device.

Claims

1. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a mandrel;

and replacing the mandrel with cells of gaseous components.

2. The method of claim 1, wherein replacing the mandrel with cells of gaseous components includes replacing the mandrel with a fill material selected from the group consisting of a foamed polymeric material, a cured aerogel and an air gap.

3. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a polymeric material; and

foaming the polymeric material.

4. The method of claim 3, wherein filling the trench with a polymeric material includes filling the trench with a polymeric material selected from the group consisting of methylsilsesquioxane, polyimides and polynorbomenes.

5. The method of claim 3, wherein filling the trench with a polymeric material includes filling the trench with a polymeric material selected from the group consisting of Type I and Type III polyimides.

6. The method of claim 3, wherein foaming the polymeric material further comprises:

exposing the polymeric material to a supercritical fluid, thereby forming a saturated polymeric material; and

depressurizing the saturated polymeric material, thereby forming cells.

7. The method of claim 3, wherein foaming the polymeric material further comprises:

exposing the polymeric material to supercritical carbon dioxide, thereby forming a saturated polymeric material; and

depressurizing the saturated polymeric material, thereby forming cells.

8. The method of claim 3, wherein the method is performed in the order presented.

9. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with an aerogel material; and

curing the aerogel material.

10. The method of claim 9, wherein filling the trench with an aerogel material includes filling the trench with a silica aerogel material material.

11. The method of claim 9, wherein filling the trench with an aerogel material includes filling the trench with a methylsilsesquioxane (MSSQ) material.

12. The method of claim 9, wherein the method is performed in the order presented.

13. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a first polymeric material;

defining additional structures in the integrated circuit device;

removing the first polymeric material;

filling the trench with a second polymeric material; and

foaming the second polymeric material.

14. The method of claim 13, wherein removing the first polymeric material includes decomposing the polymeric material.

15. The method of claim 13, wherein removing the first polymeric material includes exposing the polymeric material to a plasma selected from the group consisting of an oxygen plasma and an ozone plasma.

16. The method of claim 13, wherein the method is performed in the order presented.

17. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a methylsilsequioxane material;

defining additional structures in the integrated circuit device;

removing the methylsilsequioxane material;

filling the trench with a polymeric material; and

foaming the polymeric material.

18. The method of claim 17, wherein foaming the polymeric material includes foaming a polymeric material selected from the group consisting of methylsilsesquioxane, polyimides and polynorbomenes.

19. The method of claim 17, wherein the method is performed in the order presented.

20. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a polymeric material;

defining additional structures in the integrated circuit device;

removing the polymeric material;

filling the trench with an aerogel material; and

curing the aerogel material.

21. The method of claim 20, wherein the method is performed in the order presented.

22. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a polymeric material;

exposing the polymeric material to a supercritical fluid, thereby forming a saturated polymeric material; and

depressurizing the saturated polymeric material, thereby forming cells.

23. The method of claim 22, wherein filling the trench with the polymeric material includes filling the trench with a polymeric material selected from the group consisting of methylsilsesquioxane, polyimides and polynorbomenes.

24. The method of claim 22, wherein the method is performed in the order presented.

25. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a polyimide material;

exposing the polyimide material to a supercritical fluid, thereby forming a saturated polyimide material; and

depressurizing the saturated polyimide material, thereby forming cells.

26. The method of claim 25, wherein filling the trench with a polyimide material includes filling the trench with a polyimide material selected from the group consisting of Type I and Type III polyimides.

27. The method of claim 25, wherein the method is performed in the order presented.

28. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a polynorbomene material;

exposing the polynorbomene material to a supercritical fluid, thereby forming a saturated polynorbomene material; and

depressurizing the saturated polynorbomene material, thereby forming cells.

29. The method of claim 28, wherein the method is performed in the order presented.

30. A method of isolating a first active region from a second active region in an integrated circuit device, comprising:

forming a trench in a substrate, wherein the first active region is on a first side of the trench and the second active region is on a second side of the trench;

filling the trench with a methylsilsesquioxane material;

exposing the methylsilsesquioxane material to a supercritical fluid, thereby forming a saturated methylsilsesquioxane material; and

depressurizing the saturated methylsilsesquioxane material, thereby forming cells.

31. The method of claim 30, wherein the method is performed in the order presented.