Low dielectric constant shallow trench isolation

• US 6,737,723 B2
• Filed: 06/27/2002
• Issued: 05/18/2004
• 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): WILSON, CHRISTIAN D
• Application Number:
  US10/184,321
• Publication Number:
  US 20020163044A1
• Time in Patent Office: 691 Days
• Field of Search: 257/510, 257/522, 438/296, 438/421, 438/424
• US Class Current: 257/510
• 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. 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. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench contains cells of gaseous components; and

a metal interconnect structure located over a portion of the cells of gaseous components and electrically in communication with the first active region and the second active region.

2. The integrated circuit device of claim 1, wherein the trench contains a fill material selected from the group consisting of a foamed polymeric material, a cured aerogel and an air gap.

3. The integrated circuit device of claim 2, wherein the foamed polymeric material comprises a polymeric material selected from the group consisting of methylsilsesquioxane, polyimides and polynorbornenes.

4. The integrated circuit device of claim 2, wherein the foamed polymeric material comprises a polymeric material selected from the group consisting of Type I and Type III polyimides.

5. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed polymeric material; and

a metal interconnect structure located over a portion of the foamed polymeric material and electrically in communication with the first active region and the second active region.

6. The integrated circuit device of claim 5, wherein the layer of material includes a metal interconnect structure in electrical communication between the first active region and the second active region.

7. The integrated circuit device of claim 6, wherein the metal interconnect structure includes a refractory metal.

8. The integrated circuit device of claim 6, wherein the metal interconnect structure includes tungsten.

9. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a cured aerogel; and

a metal interconnect structure located over a portion of the cured aerogel and electrically in communication with the first active region and the second active region.

10. The integrated circuit device of claim 9, wherein the cured aerogel includes a silica aerogel.

11. The integrated circuit device of claim 9, wherein the cured aerogel includes a methylsilsesquioxane (MSSQ) material.

12. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with an air gap; and

a conducting layer located over a portion of the air gap, wherein the conducting layer forms a direct interface with the air gap.

13. The integrated circuit device of claim 12, wherein the conducting layer includes a metal interconnect structure in electrical communication between the first active region and the second active region.

14. The integrated circuit device of claim 13, wherein the metal interconnect structure includes a refractory metal.

15. The integrated circuit device of claim 13, wherein the metal interconnect structure includes tungsten.

16. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed polyimide material; and

a metal interconnect structure located over a portion of the foamed polyimide material and electrically in communication with the first active region and the second active region.

17. The integrated circuit device of claim 16, wherein the a foamed polyimide material includes an elastic modulus of less than about 1.4 GPa and a coefficient of thermal expansion of about 20 μ

m/m°

C.

18. The integrated circuit device of claim 16, wherein the a foamed polyimide material includes an elastic modulus of less than about 2.4 GPa and a coefficient of thermal expansion of about 40 μ

m/m°

C.

19. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed Type I polyimide material; and

a metal interconnect structure located over a portion of the foamed Type I polyimide material and electrically in communication with the first active region and the second active region.

20. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed Type III polyimide material; and

a metal interconnect structure located over a portion of the foamed Type III polyimide material and electrically in communication with the first active region and the second active region.

21. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed polynorbornene material; and

a metal interconnect structure located over a portion of the foamed polynorbornene material and electrically in communication with the first active region and the second active region.

22. An integrated circuit device, comprising:

a first active region formed in a substrate;

a second active region formed in the substrate;

a trench formed in the substrate and interposed between the first active region and the second active region;

wherein the trench is filled with a foamed methylsilsesquioxane material; and

a metal interconnect structure located over a portion of the foamed methylsilsesquioxane material and electrically in communication with the first active region and the second active region.

23. A semiconductor die, comprising:

an integrated circuit supported by a substrate and having a plurality of semiconductor devices, wherein at least two of the plurality of semiconductor devices are isolated by an interposing trench, and wherein the trench contains cells of gaseous components; and

a metal interconnect structure located over a portion of the cells of gaseous components and electrically in communication with the plurality of semiconductor devices.

24. The semiconductor die of claim 23, wherein the trench contains a fill material selected from the group consisting of a foamed polymeric material, a cured aerogel and an air gap.

25. The semiconductor die of claim 24, wherein the foamed polymeric material comprises a polymeric material selected from the group consisting of methylsilsesquioxane, polyimides and polynorbornenes.

26. The semiconductor die of claim 24, wherein the foamed polymeric material comprises a polymeric material selected from the group consisting of Type I and Type III polyimides.

27. A semiconductor die, comprising:

an integrated circuit supported by a substrate and having a plurality of semiconductor devices, wherein at least two of the plurality of semiconductor devices are isolated by an interposing trench, and wherein the trench is filled with a foamed polymeric material; and

a metal interconnect structure located over a portion of the foamed polymeric material and electrically in communication with the plurality of semiconductor devices.

28. A semiconductor die, comprising:

an integrated circuit supported by a substrate and having a plurality of semiconductor devices, wherein at least two of the plurality of semiconductor devices are isolated by an interposing trench, and wherein the trench is filled with a cured aerogel; and

a metal interconnect structure located over a portion of the cured aerogel and electrically in communication with the plurality of semiconductor devices.

29. A semiconductor die, comprising:

an integrated circuit supported by a substrate and having a plurality of semiconductor devices, wherein at least two of the plurality of semiconductor devices are isolated by an interposing trench, and wherein the trench is filled with an air gap; and

a conducting layer located over a portion of the air gap, wherein the conducting layer forms a direct interface with the air gap.