Photoresist strip processes for improved device integrity

Patent metadata

Field	Value
Publication number	US-9613825-B2
Application number	US-201213590083-A
Country	US
Kind code	B2
Filing date	Aug 20, 2012
Priority date	Aug 26, 2011
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

Provided herein are methods and apparatus of hydrogen-based photoresist strip operations that reduce dislocations in a silicon wafer or other substrate. According to various embodiments, the hydrogen-based photoresist strip methods can employ one or more of the following techniques: 1) minimization of hydrogen budget by using short processes with minimal overstrip duration, 2) providing dilute hydrogen, e.g., 2%-16% hydrogen concentration, 3) minimization of material loss by controlling process conditions and chemistry, 4) using a low temperature resist strip, 5) controlling implant conditions and concentrations, and 6) performing one or more post-strip venting processes. Apparatus suitable to perform the photoresist strip methods are also provided.

First claim

The invention claimed is:

1. A method comprising:
providing a substrate having an exposed silicon surface and an ion-implanted photoresist, the ion-implanted photoresist including a bulk photoresist and a carbonized outer layer on the bulk photoresist, disposed thereon to reaction chamber;
exposing the substrate to a plasma generated from a process gas consisting essentially of nitrogen (N 2 ) and hydrogen (H 2 ), wherein the volumetric flow percentage of H 2 in the process gas is between about 2% and 16% and the balance of the process gas is N 2 , to thereby remove photoresist from the substrate, wherein the substrate temperature is between about 200° C. and 285° C. and the chamber pressure is between 600 mTorr and 2 Torr.

2. The method of claim 1 , wherein the volumetric flow percentage of H 2 is between about 2% and 10%.

3. The method of claim 1 , wherein the volumetric flow percentage of H 2 is less than about 8%.

4. The method of claim 1 , wherein the volumetric flow percentage of H 2 is about 4%.

5. The method of claim 1 , wherein the substrate is exposed to the plasma for a time t and the cross-product of the volumetric flow percentage of H 2 [H] and the time t ([H]×t) is between about 50 and 2000 sccm-seconds.

6. The method of claim 5 , wherein [H]×t is between about 50 and 500 sccm-seconds.

7. The method of claim 1 , wherein the substrate temperature is between about 200° C. and 250° C.

8. The method of claim 1 , further comprising applying photoresist to the substrate, exposing the photoresist to light, patterning the photoresist and transferring the pattern to the substrate.

9. A method comprising:
providing a substrate having photoresist disposed thereon to reaction chamber;
exposing the substrate to a plasma generated from a process gas consisting essentially of hydrogen gas (H 2 ) and nitrogen gas (N 2 ) wherein H 2 is present at a first volumetric flowrate and the balance of the process gas is N 2 and the N 2 is present in a higher volumetric flow percentage than H 2 to thereby remove photoresist from the substrate, wherein the substrate temperature is between about 200° C. and 285° C. and the chamber pressure is between 600 mTorr and 2 Torr;
after exposing the substrate to the plasma, venting the substrate by exposing the substrate to a thermal anneal at a substrate temperature between about 200° C. and 450° C. to thereby remove incorporated hydrogen from a crystalline silicon (Si) surface of the substrate.

10. The method of claim 9 , further comprising after venting the substrate, performing a high temperature implant drive process at a substrate temperature of at least about 800° C.

11. The method of claim 9 , wherein the volumetric flow percentage of H 2 in the process gas is 16% or greater.

12. The method of claim 9 , wherein the volumetric flow percentage of H 2 in the process gas is less than 16%.

13. The method of claim 9 , wherein the volumetric flow percentage of H 2 in the process gas is less than 10%.

14. The method of claim 9 , wherein the volumetric flow percentage of H 2 in the process gas is less than 5%.

15. The method of claim 9 , wherein the substrate is vented at a temperature less than 400° C.

16. The method of claim 9 , wherein hydrogen is incorporated into the crystalline silicon surface during the exposing operation.

17. An apparatus comprising:
a plasma source,
a gas inlet for introducing a gas mixture into the plasma source,
a showerhead positioned downstream of the gas inlet, and

a substrate support downstream of the showerhead, said substrate support comprising a pedestal and temperature-controlling mechanism to control a temperature of a substrate supported on the substrate support; and, a controller for executing a set of instructions, said set of instructions comprising instructions to introduce a gas mixture to the gas inlet consisting essentially of nitrogen (N 2 ) and hydrogen (H 2 ) and having a volumetric flow percentage of H 2 of between about 2% and 16%, wherein the balance of the gas mixture is N 2 and further wherein said set of instructions comprise instructions to expose the substrate to a plasma generated from the gas mixture for a time t such that the cross-product of the volumetric flow percentage of H 2 [H] and the time t ([H]×t) is between about 50 and 2000 sccm-seconds, and to maintain the substrate temperature between about 200° C. and 285° C. and the chamber pressure between 600 mTorr and 2 Torr.

18. The apparatus of claim 17 , wherein [H]×t is between about 50 and 500 sccm-seconds.

Assignees

• Shaviv Roey
• Ostrowski Kirk
• Cheung David
• Park Joon
• Thedjoisworo Bayu
• Lord Patrick J
• Novellus Systems Inc

Inventors

• Shaviv Roey
• Ostrowski Kirk
• Cheung David
• Park Joon
• Thedjoisworo Bayu
• Lord Patrick J

Classifications

• H10P50/287 Primary

  by chemical means · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• G03F7/427

  using plasma means only · CPC title

• H01J37/32449

  Gas control, e.g. control of the gas flow · CPC title

• H01J37/32724

  Temperature · CPC title