Methods for reduced gate resistance FINFET

• US 8,759,181 B2
• Filed: 06/26/2013
• Issued: 06/24/2014
• Est. Priority Date: 12/14/2011
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Jou, Chewn-Pu, Yeh, Tzu-Jin, Hsieh, Hsieh-Hung
• Primary Examiner(s): Sun, Yu-Hsi D
• Assistant Examiner(s): WITHERS, GRANT S
• Application Number:
  US13/927,340
• Publication Number:
  US 20130288443A1
• Time in Patent Office: 363 Days
• Field of Search: 438/283
• US Class Current: 438/283
• CPC Class Codes: H01L 29/42372 characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out H01L29/42324 takes precedence
• CPC Class Codes: H01L 29/66795 with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/785 having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

Methods for forming reduced gate resistance finFETs. Methods for a metal gate transistor structure are disclosed including forming a plurality of semiconductor fins formed over a semiconductor substrate, the fins being arranged in parallel and spaced apart; a metal containing gate electrode formed over the semiconductor substrate and overlying a channel gate region of each of the semiconductor fins, and extending over the semiconductor substrate between the semiconductor fins; an interlevel dielectric layer overlying the gate electrode and the semiconductor substrate; and a plurality of contacts disposed in the interlevel dielectric layer and extending through the interlevel dielectric layer to the gate electrode; a low resistance metal strap formed over the interlevel dielectric layer and coupled to the gate electrode by the plurality of contacts; wherein the plurality of contacts are spaced apart from the channel gate regions of the semiconductor fins. Additional methods are disclosed.

Claims

1. A method comprising:

forming multiple semiconductor fins over a semiconductor substrate, the multiple semiconductor fins spaced apart;

forming a metal containing gate electrode overlying a channel gate region of each of the semiconductor fins, and extending over the semiconductor substrate between the semiconductor fins;

forming an interlevel dielectric layer overlying the metal containing gate electrode and the semiconductor substrate;

forming a plurality of contacts extending through the interlevel dielectric layer to the metal containing gate electrode, each of the plurality of contacts spaced from the channel gate regions of the semiconductor fins; and

forming a metal strap layer over the interlevel dielectric layer coupled to the metal containing gate electrode through the plurality of contacts.

2. The method of claim 1 and further comprising forming a high-K gate dielectric layer between the gate electrode and the channel gate regions of the multiple semiconductor fins.

3. The method of claim 2 wherein the metal containing gate electrode and multiple semiconductor fins form multiple finFET devices.

4. The method of claim 1 wherein each of the plurality of contacts overlies a portion of the gate electrode that is between the multiple semiconductor fins.

5. The method of claim 4, wherein each of the plurality of contacts is formed spaced a minimum distance from the channel gate regions of any of the semiconductor fins, the minimum distance being greater than or equal to about 8 nanometers.

6. The method of claim 1, wherein forming multiple semiconductor fins over a semiconductor substrate further comprises patterning a bulk semiconductor substrate by etching to form the multiple semiconductor fins.

7. The method of claim 1, wherein forming multiple semiconductor fins over a semiconductor substrate further comprises:

forming an insulator layer over the semiconductor substrate;

forming an epitaxial semiconductor layer over the insulator layer; and

patterning the epitaxial layers to form the multiple semiconductor fins.

8. The method of claim 1, and further comprising:

forming the strap layer overlying and in parallel to the metal containing gate electrode.

9. The method of claim 1, wherein the metal strap layer extends over a first portion of the metal containing gate electrode, and a second portion of the metal containing gate electrode is not covered by the metal strap layer.

10. A method for forming a multiple fin finFET device, comprising:

forming multiple semiconductor fins over a semiconductor substrate, the multiple semiconductor fins spaced apart;

forming a gate dielectric layer over the multiple semiconductor fins to define a channel gate region of each of the multiple semiconductor fins

forming a metal containing gate electrode overlying a channel gate region of each of the multiple semiconductor fins, and extending over the semiconductor substrate between the semiconductor fins;

forming an interlevel dielectric layer overlying the metal containing gate electrode and the semiconductor substrate;

forming a plurality of vertical contacts extending through the interlevel dielectric layer to the metal containing gate electrode, each of the plurality of vertical contacts spaced from the channel gate regions of the semiconductor fins; and

forming a metal strap layer over the interlevel dielectric layer coupled to the metal containing gate electrode through the plurality of contacts.

11. The method of claim 10, wherein the gate dielectric layer is one selected from the group consisting essentially of an oxide layer and one of tantalum, aluminum, and hafnium.

12. The method of claim 10, wherein the gate dielectric layer has a dielectric constant K that is greater than about 3.8.

13. The method of claim 12, wherein the gate dielectric layer has a dielectric constant K that is greater than about 10.

14. The method of claim 10, wherein forming the metal containing gate electrode further comprises forming a metal gate electrode with a planar top surface.

15. The method of claim 10, wherein forming the metal containing gate electrode further comprises forming a metal gate electrode that is conformally deposited over the multiple semiconductor fins and between the multiple semiconductor fins.

16. The method of claim 10, and further comprising forming source and drain regions in the multiple semiconductor fins by providing dopants into the multiple semiconductor fins.

17. A method for forming a finFET device, comprising:

providing a semiconductor substrate;

patterning the semiconductor substrate to form multiple semiconductor fins in parallel and spaced apart one from another;

depositing a gate dielectric over the multiple semiconductor fins;

depositing a metal containing gate electrode over the gate dielectric;

patterning the gate dielectric and the metal containing gate electrode to form channel gate regions over the multiple semiconductor fins;

forming an interlevel dielectric layer overlying the metal containing gate electrode and the semiconductor substrate;

forming a plurality of vertical contacts extending through the interlevel dielectric layer to the metal containing gate electrode, each of the plurality of vertical contacts spaced from the channel gate regions of the semiconductor fins; and

forming a metal strap layer over the interlevel dielectric layer coupled to the metal containing gate electrode through the plurality of contacts.

18. The method of claim 17, wherein the metal strap layer further comprises a conductor having a resistance per unit area that is lower than the resistance per unit area of the metal containing gate electrode.

19. The method of claim 17, wherein the plurality of contacts are formed between the semiconductor fins and spaced from the channel gate regions by a minimum spacing distance.

20. The method of claim 19, wherein the minimum spacing distance is between about 8 and about 12 nanometers.