Planarization of a Material System in a Semiconductor Device by Using a Non-Selective In Situ Prepared Slurry

• US 20110269381A1
• Filed: 12/16/2010
• Published: 11/03/2011
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Hueselitz, Rico, Kitsche, Marco, Steffen, Katja, Groschopf, Johannes
• Granted Patent: US 8,585,465 B2
• Time in Patent Office: Days
• US Class Current: 451/54
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 29/66545 using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
• CPC Class Codes: H01L 29/7833 with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's for thin film transistors H01L29/78618

Abstract

For complex CMP processes requiring the removal of different dielectric materials, possibly in the presence of a polysilicon material, a slurry material may be adapted at the point of use by selecting an appropriate pH value and avoiding agglomeration of the abrasive particles. The in situ preparation of the slurry material may also enable a highly dynamic adaptation of the removal conditions, for instance when exposing the polysilicon material of gate electrode structures in replacement gate approaches.

Claims

1. A method of planarizing a surface of a semiconductor device in the presence of at least two different dielectric materials, the method comprising:

providing a first solution in a manufacturing environment, said first solution having a first pH value and comprising abrasive particles;

providing a second solution in said manufacturing environment, said second solution comprising an acid;

producing a slurry solution in said manufacturing environment from at least said first and second solutions, said slurry solution having a second pH value that is less than said first pH value, said second pH value resulting in an approximation of removal rates of said at least two different dielectric materials for a given percentage of said abrasive particles in said slurry solution so as to adjust a balance of said removal rates; and

performing a planarization process in said manufacturing environment using said slurry solution produced in said manufacturing environment.

2. The method of claim 1, wherein said at least two different dielectric materials comprise silicon dioxide and silicon nitride.

3. The method of claim 2, wherein said planarization process is performed in the presence of polysilicon.

4. The method of claim 1, wherein producing said slurry solution further comprises stabilizing said slurry solution so as to avoid agglomeration of abrasive particles at said second pH value.

5. The method of claim 4, wherein stabilizing said slurry solution comprises adding de-ionized water.

6. The method of claim 4, wherein stabilizing said slurry solution comprises adding a surfactant.

7. The method of claim 1, further comprising adjusting said balance of removal rates of said at least two dielectric materials by dynamically varying said percentage of abrasive particles when producing said slurry solution.

8. The method of claim 7, further comprising obtaining a status signal when performing said planarization process and adjusting said balance of removal rates in correlation to said status signal.

9. The method of claim 1, further comprising forming a silicon dioxide material and a silicon nitride material above a gate electrode structure that comprises a semiconductor material and performing said planarization process so as to expose a surface of said semiconductor material.

10. The method of claim 1, wherein said second pH value is adjusted to a value between 6.5 and 8 and wherein a percentage of said abrasive particles is selected between 6 weight percent and 9 weight percent.

11. A method, comprising:

producing a slurry solution having a matched removal rate for silicon dioxide and silicon nitride by adjusting a pH value and stabilizing said slurry solution so as to avoid agglomeration of abrasive particles of said slurry solution; and

performing a planarization process for removing at least silicon dioxide and silicon nitride from a semiconductor device by using said slurry solution so as to expose a polysilicon material of a gate electrode structure.

12. The method of claim 11, wherein adjusting a pH value of said slurry solution comprises adding an acid to a caustic slurry base material so as obtain a pH value in the range of 6.5 and 8.

13. The method of claim 11, wherein stabilizing said slurry solution comprises adding at least one of de-ionized water and a surfactant.

14. The method of claim 13, wherein at least said surfactant is added so as to further adjust a removal rate of said semiconductor material in said gate electrode structure.

15. The method of claim 11, further comprising dynamically adapting a balance of removal rates of said silicon dioxide material and said silicon nitride material by adjusting a percentage of said abrasive particles.

16. The method of claim 15, wherein dynamically adapting said balance comprises adapting said balance during said planarization process by obtaining a status signal from said planarization process.

17. The method of claim 11, wherein producing said slurry solution and said planarization process are performed in the same manufacturing environment.

18. A chemical mechanical planarization system for concurrently removing at least two different dielectric materials from a single substrate, comprising:

a process chamber configured to receive and hold in place said substrate, said process chamber comprising a slurry supply unit;

a first supply unit for providing a first solution comprising abrasive particles;

a second supply unit for providing a pH value adjusting solution comprising at least one of a surfactant and de-ionized water; and

a mixer unit connected to said first and second supply units and configured to produce a homogenous blend from said first solution and said pH value adjusting solution so as to provide a substantially matched removal rate for silicon dioxide material and silicon nitride material, said mixer unit being operatively connected to said slurry supply unit.

19. The chemical mechanical planarization system of claim 18, further comprising a control unit operatively connected to said mixer unit and configured to cause said mixer unit to dynamically adjust a percentage of said abrasive particles.

20. The chemical mechanical planarization system of claim 19, further comprising a monitor unit configured to generate a status signal indicating a current status of said substrate being processed, wherein said control unit is further configured to cause said mixer unit to dynamically adjust the percentage of said abrasive particles in correlation with said status signal.