Method of low-K/copper dual damascene

• US 6,309,957 B1
• Filed: 04/03/2000
• Issued: 10/30/2001
• Est. Priority Date: 04/03/2000
• Status: Expired due to Term

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Tai, Shih-Kuan, Yeu, Tzu-Shih, Tu, An-Chun
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): HOANG, QUOC DINH
• Application Number:
  US09/541,489
• Time in Patent Office: 575 Days
• Field of Search: 438/584, 438/622, 438/624, 438/625, 438/638, 438/637, 438/645, 438/647, 438/687
• US Class Current: 438/622
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 2221/1026 the via being formed by burying a sacrificial pillar in the dielectric and removing the pillar

Abstract

This invention relates to a method of fabrication used for semiconductor integrated circuit devices, and more specifically to both dual and single inverse copper damascene processes to form conducting copper interconnects and contact vias simultaneously, with low dielectric constant intermetal dielectrics (IMD). The low dielectric constant material, low-K, can be of four types of material: doped oxide, organic materials, highly fluorinated films, porous materials. In addition, spin-on glass (SOG) and spin-on-dielectric (SOD) are applicable. Key to the present invention are the following process steps, that have exceptionally advanced process controls: polysilicon etching of sacrificial polysilicon, plasma ashing of the patterning photoresist, and post cleaning. With conventional dual damascene, wherein dielectric material is patterned into dual damascene, several deleterious effects occur: (1) etching of low-K material can be difficult and can affect the electrical properties, (2) photoresist ashing can impact both the dielectric constant of low-K material and critical dimensional bias control, (3) post cleaning can impact the dielectric constant of low-K material. Using both the inverse dual and single damascene processes disclosed by this invention, the problems associated with convention damascene approaches are circumvented.

Claims

1. A method for fabricating conductive inlaid copper interconnects and contact vias for applications in MOSFET and CMOS semiconductor devices using an inverse copper dual damascene comprising:

providing a substrate over which is formed an interlevel dielectric;

forming a first level of conductive wiring over said interlevel dielectric;

forming an insulating layer around said first level of conductive wiring and over interlevel dielectric;

forming sacrificial polysilicon islands over said first level of conducting wiring and insulating layer;

depositing low dielectric material over said sacrificial polysilicon islands and insulating layer;

planarizing the excess said sacrificial polysilicon islands and excess said low dielectric material;

forming sacrificial polysilicon lines over said polysilicon islands and said low dielectric material;

depositing a layer of low dielectric material over said sacrificial polysilicon lines and low dielectric;

planarizing the excess said sacrificial polysilicon lines and excess said layer of low dielectric material;

removing all of the said sacrificial polysilicon lines and islands forming dual damascene, trench interconnect and contact via openings;

filling said interconnect and via with inlaid copper, planarizing surface to remove excess metal.

2. The method of claim 1, wherein said substrate is semiconductor single crystal silicon or an IC module.

3. The method of claim 1, wherein low dielectric material layers for inverse dual damascene build are selected from the group consisting of doped oxide, organic materials, highly fluorinated films, porous materials, spin-on glass (SOG), chemical vapor deposited (CVD) glass and spin-on-dielectric (SOD), in the thickness range from approximately 3,000 to 5,000 Angstroms thick for each low dielectric material layer.

4. The method of claim 1, wherein the sacrificial material for inverse dual damascene build are selected from the group consisting of polysilicon, silicon nitride, and metal.

5. The method of claim 1, wherein the inverse dual damascene interconnect trench openings and contact via openings are formed by removing sacrificial material from the group consisting of polysilicon, silicon nitride, and metal.

6. The method of claim 1, wherein the excess sacrificial materials and excess low dielectric constant materials for inverse dual damascene build are planarized by removing the excess materials, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching.

7. The method of claim 1, wherein the excess conducting copper metal for dual damascene fill is planarized by removing the excess copper conducting material, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching, leaving copper dual inlaid for interconnects and contact vias.

8. The method of claim 1, wherein multilevel conducting structures are fabricating by repeating the process described herein.

9. A method for fabricating conductive inlaid copper interconnect/contact vias for applications in MOSFET and CMOS semiconductor devices using an inverse copper single damascene comprising:

providing a substrate over which is formed an interlevel dielectric;

forming a first level of conductive wiring over said interlevel dielectric;

forming an insulating layer around said first level of conductive wiring and over said interlevel dielectric;

forming sacrificial polysilicon structures over said first level of conducting wiring and said insulating layer;

depositing low dielectric constant material over said sacrificial polysilicon structures and said insulating layer;

planarizing the excess said sacrificial polysilicon. and excess said low dielectric constant material;

removing all of the said sacrificial polysilicon forming single damascene trench/via openings;

filling said trench/via openings with inlaid copper, planarizing surface to remove excess metal.

10. The method of claim 9, wherein said substrate is semiconductor single crystal silicon or an IC module.

11. The method of claim 9, wherein low dielectric constant material layer for inverse single damascene build is selected from the group consisting of doped oxide, organic materials, highly fluorinated films, porous materials, spin-on glass (SOG), chemical vapor deposited (CVD) glass and spin-on-dielectric (SOD), in the thickness range from approximately 3,000 to 5,000 Angstroms thick.

12. The method of claim 9, wherein the sacrificial material for inverse single damascene build is selected from the group consisting of polysilicon, silicon nitride, and metal.

13. The method of claim 9, wherein the inverse single damascene interconnect trench opening/contact via opening is formed by removing sacrificial material from the group consisting of polysilicon, silicon nitride, and metal.

14. The method of claim 9, wherein the excess sacrificial material and excess low dielectric constant material for inverse single damascene build is planarized by removing the excess materials, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching.

15. The method of claim 9, wherein the excess conducting copper metal for single damascene fill is planarized by removing the excess copper conducting material, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching, leaving copper single inlaid for interconnect/contact via.

16. The method of claim 9, wherein multilevel conducting structures are fabricating by repeating the process described herein.

17. A method for fabricating conductive inlaid interconnects and contact vias for applications in semiconductor devices using an inverse dual damascene process comprising:

providing a substrate over which is formed an interlevel dielectric;

forming a first level of conductive wiring over said interlevel dielectric;

forming an insulating layer around said first level of conductive wiring and over interlevel dielectric;

forming islands consisting of sacrificial material over said first level of conducting wiring and said insulating layer;

forming a first layer of low dielectric constant material around and over said islands and over said insulating layer;

removing the excess said sacrificial material and excess said low dielectric constant material to planarize the surface;

forming lines consisting of sacrificial material over said islands and said first layer of low dielectric constant material;

forming a second layer of low dielectric constant material around and over said lines and over the first layer of low dielectric constant material;

removing the excess said sacrificial material and excess said low dielectric material to planarize the surface;

removing all of the said sacrificial material, lines and islands, to form dual damascene, trench interconnect and contact via openings;

filling said interconnect and via openings with inlaid conducting material, planarizing the surface to remove excess conductive material.

18. The method of claim 17, wherein said substrate is semiconductor single crystal silicon or an IC module.

19. The method of claim 17, wherein low dielectric material layers for inverse dual damascene build are selected from the group consisting of doped oxide, organic materials, highly fluorinated films, porous materials, spin-on glass (SOG), chemical vapor deposited (CVD) glass and spin-on-dielectric (SOD), in the thickness range from approximately 3,000 to 5,000 Angstroms thick for each low dielectric material layer.

20. The method of claim 17, wherein the sacrificial material for inverse dual damascene build are selected from the group consisting of polysilicon, silicon nitride, and metal.

21. The method of claim 17, wherein the inverse dual damascene interconnect trench openings and contact via openings are formed by removing sacrificial material from the group consisting of polysilicon, silicon nitride, and metal.

22. The method of claim 17, wherein the excess sacrificial materials and excess low dielectric constant materials for inverse dual damascene build are planarized by removing the excess materials, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching.

23. The method of claim 17, wherein the conducting material to fill the dual damascene openings for interconnect lines and contact vias is selected from the group consisting of:

copper, aluminum-copper alloys, aluminum, tungsten.

24. The method of claim 17, wherein the excess conducting material for dual damascene fill is planarized by removing the excess copper conducting material, selected from the group consisting of planarization by:

chemical mechanical polish (CMP), milling, ion milling, and/or etching, leaving copper dual inlaid for interconnects and contact vias.

25. The method of claim 17, wherein multilevel conducting structures are fabricating by repeating the process described herein.

26. The method of claim 17, wherein the inverse dual damascene interconnect trench openings and contact via openings are formed by removing sacrificial material from the group consisting of polysilicon, silicon nitride, and metal, using highly selective etch processing selected from the group consisting of chemical dry etching, wet etching and spin-process etching.