SACRIFICIAL INORGANIC POLYMER INTERMETAL DIELECTRIC DAMASCENE WIRE AND VIA LINER

• US 20050153505A1
• Filed: 01/14/2004
• Published: 07/14/2005
• Est. Priority Date: 01/14/2004
• Status: Active Grant

• Current Assignee: Auriga Innovations, Inc. (Quarterhill Inc. (f/k/a Wi-LAN Inc.))
• Original Assignee: International Business Machines Corporation
• Inventors: Gambino, Jeffrey P., Stamper, Anthony K.
• Granted Patent: US 7,169,698 B2
• Time in Patent Office: Days
• US Class Current: 438/233
• CPC Class Codes: H01L 21/02118 carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC polymers per se C08G, photoresist per se G03F
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02266 deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/312 Organic layers, e.g. photoresist H01L21/3105, H01L21/32 take precedence; photoresists per se G03C
• CPC Class Codes: H01L 21/3121 Layers comprising organo-silicon compounds
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/3148 Silicon Carbide layers
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/76811 involving multiple stacked pre-patterned masks
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• CPC Class Codes: H01L 21/76835 Combinations of two or more different dielectric layers having a low dielectric constant H01L21/76832 takes precedence
• CPC Class Codes: H01L 2221/1063 Sacrificial or temporary thin dielectric films in openings in a dielectric
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/5329 : Insulating materials
• CPC Class Codes: H01L 23/53295 : Stacked insulating layers
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 : Impedance

Abstract

The present invention provides a method of forming a rigid interconnect structure, and the device therefrom, including the steps of providing a lower metal wiring layer having first metal lines positioned within a lower low-k dielectric; depositing an upper low-k dielectric atop the lower metal wiring layer; etching at least one portion of the upper low-k dielectric to provide at least one via to the first metal lines; forming rigid dielectric sidewall spacers in at least one via of the upper low-k dielectric; and forming second metal lines in at least one portion of the upper low-k dielectric. The rigid dielectric sidewall spacers may comprise of SiCH, SiC, SiNH, SiN, or SiO₂. Alternatively, the via region of the interconnect structure may be strengthened with a mechanically rigid dielectric comprising SiO₂, SiCOH, or doped silicate glass.

Claims

1. A method of forming an interconnect structure comprising the steps of:

providing a lower metal wiring layer having first metal lines located within a lower low-k dielectric;

depositing an upper low-k dielectric atop said lower metal wiring layer;

etching at least one portion of said upper low-k dielectric to provide at least one via to said first metal lines;

forming rigid dielectric sidewall spacers in said at least one via of said upper low-k dielectric, said dielectric sidewall spacers are of a material selected from the group consisting of SiCH, SiCOH, SiC and SiO₂; and

forming second metal lines in said at least one portion of said upper low-k dielectric.

2. The method of claim 1 wherein said upper low-k dielectric and said lower low-k dielectric comprise materials having a dielectric constant ranging from about 1.0 to about 3.5.

3. The method of claim 1 wherein said upper low-k dielectric and said lower low-k dielectric comprise low-k polymers or low-k carbon doped oxides.

4. (canceled)

5. The method of claim 4 wherein said forming rigid dielectric sidewall spacers further comprises:

depositing a conformal rigid dielectric liner atop said upper low-k dielectric and within said at least one via; and

etching horizontal surfaces of said conformal rigid dielectric liner to form said rigid dielectric spacers positioned on vertical sidewalls of said at least one via.

6. The method of claim 5 wherein depositing a conformal rigid dielectric liner further comprises physical vapor deposition (PVD), plasma enhanced chemical vapor deposition (PECVD), high density plasma chemical vapor deposition (HDPCVD), or low pressure chemical vapor deposition (LPCVD).

7. The method of claim 6 wherein said conformal rigid dielectric liner has a thickness ranging from about 10 nm to about 100 nm.

8. The method of claim 7 wherein said etching horizontal surfaces of said conformal rigid dielectric liner further comprises an anisotropic etch process.

9. The method of claim 8 wherein said lower metal wiring layer further comprises a rigid insulating layer deposited atop said lower low-k dielectric, said rigid insulating layer material selected from the group consisting of SiC, SiO₂, and Si₃N₄.

10. A method of forming an interconnect structure comprising the steps of:

providing a lower metal wiring level having first metal lines positioned within a lower low-k dielectric;

depositing a mechanically rigid dielectric layer atop said lower metal wiring level, said mechanically rigid dielectric layer is a material selected from the group consisting of SiO₂, a doped silicate glass, a carbon doped oxide and SiC;

forming at least one via through said mechanically rigid dielectric layer to a portion of said first metal lines; and

forming an upper metal wiring level having second metal lines positioned within a upper low-k dielectric, said second metal lines being electrically connected to said first metal lines through said via, wherein said via comprises a metal having a coefficient of thermal expansion that substantially matches said mechanically rigid dielectric layer, said mechanically rigid dielectric layer separating said upper metal wiring level from said lower metal wiring level.

11. The method of claim 10 wherein said mechanically rigid dielectric comprises a coefficient of thermal expansion ranging from about 0.1 ppm/°

C. to about 5.0 ppm/°

C.

13. The method of claim 10 wherein said mechanically rigid dielectric has a thickness ranging from about 100 nm to about 1000 nm.

14. The method of claim 10 wherein said upper low-k dielectric and said lower low-k dielectric comprise materials having a dielectric constant of less than about 3.5.

15. The method of claim 14 wherein said upper low-k dielectric and said lower low-k dielectric comprise low-k polymers or low-k carbon doped oxides.

16. The method of claim 15 wherein said low-k polymer is a b-staged polymer comprising about 95% carbon.

17. The method of claim 15 wherein said low-k carbon doped oxide is SiCOH.

18. The method of claim 10 wherein said second metal lines, said first metal lines or a combination of said second metal lines and said first metal lines comprise copper, aluminum, silver, gold or alloys thereof.

12. (canceled)

19. An interconnect structure comprising:

a lower metal wiring level comprising first metal lines positioned within a lower low-k dielectric;

an upper metal wiring level atop said lower metal wiring level, said upper metal wiring level comprising second metal lines positioned within an upper low-k dielectric;

and a plurality of vias through a portion of said upper low-k dielectric electrically connecting said lower metal wiring level and said upper metal wiring level, where said plurality of vias comprise a set of rigid dielectric sidewall spacers.

20. The interconnect structure of claim 19 wherein said set of rigid dielectric sidewall spacers comprise SiCH, SiC, SiNH, SiN, or SiO₂.

21. The interconnect structure of claim 20 wherein each of said set of rigid dielectric sidewall spacers have a thickness ranging from about 10 nm to about 100 nm.

22. An interconnect structure comprising:

a lower metal wiring level comprising first metal lines positioned within a lower low-k dielectric;

a mechanically rigid dielectric positioned on said lower metal wiring level, said mechanically rigid dielectric comprising a plurality of metal vias; and

an upper metal wiring level atop said mechanically rigid dielectric, said upper metal wiring level comprising second metal lines positioned within an upper low-k dielectric, where said plurality of metal vias electrically connect said lower metal wiring level and said upper metal wiring level.

23. The interconnect structure of claim 22 wherein said mechanically rigid dielectric comprises SiO₂, SiCOH, or doped silicate glass.

24. The interconnect structure of claim 22 wherein said plurality of metal vias has a coefficient of thermal expansion matched to said mechanically rigid dielectric.