Techniques for forming low stress mask using implantation

Patent metadata

Field	Value
Publication number	US-10515802-B2
Application number	US-201816030311-A
Country	US
Kind code	B2
Filing date	Jul 9, 2018
Priority date	Apr 20, 2018
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

A method may include depositing a mask layer on a substrate using physical vapor deposition, wherein an absolute value of a stress in the mask layer has a first value; and directing a dose of ions into the mask layer, wherein the absolute value of the stress in the mask layer has a second value, less than the first value, after the directing the dose.

First claim

What is claimed is:

1. A method, comprising:
depositing a mask layer on a substrate using physical vapor deposition, the mask layer having a mask thickness, wherein an absolute value of a stress in the mask layer has a first value; and
directing a dose of ions into the mask layer, wherein the absolute value of the stress in the mask layer has a second value, less than the first value, after the directing the dose of ions, wherein the directing the dose of ions comprises:
choosing an ion species and ion energy for the dose of ions,
wherein the directing the dose of ions causes the ion species to be implanted to an implant range R p , wherein R p is between 40% and 66% of the mask thickness;
and causes the ion species to be implanted to an implant depth, the implant depth being given by R p +3(LS), where LS is longitudinal straggle, and wherein the value of the implant depth is greater than 50% of the mask thickness and less than 100% of the mask thickness.

2. The method of claim 1 , wherein the mask layer is a SiN material.

3. The method of claim 1 , comprising: implanting the dose of ions at room temperature.

4. The method of claim 1 , comprising implanting the dose of ions at less than 0° C.

5. The method of claim 1 , comprising implanting the dose of ions at −100° C.

6. The method of claim 2 , wherein the first value comprises a level of compressive stress between 200 MPa and 3 GPa.

7. The method of claim 6 , wherein the second value comprises a stress value between 200 MPa compressive stress to 200 MPa tensile stress.

8. The method of claim 2 , wherein the dose of ions comprises Si ions, Ar ions, BF 2 ions, Ge ions, As ions, or Xe ions.

9. The method of claim 2 , wherein the dose of ions comprises a dose range of 2E15/cm 2 to 1E16/cm 2 .

10. The method of claim 1 , wherein the implant range is between 40% and 50% of the mask thickness.

11. The method of claim 1 , wherein the mask layer comprises a mask thickness of 20 nm to 100 nm.

12. A method for fabricating a low stress layer, comprising:
depositing a mask layer, comprising SiN, on a substrate using physical vapor deposition, wherein an absolute value of a stress in the mask layer has a first value;
cooling the substrate to an implantation temperature, the implantation temperature being below room temperature; and
directing a dose of ions into the mask layer when the substrate is at the implantation temperature, wherein the absolute value of the stress in the mask layer has a second value, less than the first value, after the directing the dose, wherein the directing the dose of ions comprises:
choosing an ion species and ion energy for the dose of ions,
wherein the directing the dose of ions causes the ion species to be implanted to an implant range R p , wherein R p is between 40% and 66% of the mask thickness;
and causes the ion species to be implanted to an implant depth, the implant depth being given by R p +3(LS), where LS is longitudinal straggle, and wherein the value of the implant depth is greater than 50% of the mask thickness and less than 100% of the mask thickness.

13. The method of claim 12 , wherein the implantation temperature is −100° C.

14. The method of claim 12 , wherein the first value corresponds to a compressive stress in a range of 200 MPa to 2 GPa.

15. A method for fabricating a low stress layer, comprising:
depositing a SiN layer on a substrate using physical vapor deposition, wherein an absolute value of a stress in the SiN layer has a first stress value, and wherein the SiN layer exhibits a first density; and
directing a dose of ions into the SiN layer, wherein the absolute value of the stress in the mask layer has a second value, less than the first value, and wherein the SiN layer exhibits a second density, at least 90% of the first density, after the directing the dose, wherein the directing the dose of ions comprises:
choosing an ion species and ion energy for the dose of ions,
wherein the directing the dose of ions causes the ion species to be implanted to an implant range R p , wherein R p is between 40% and 66% of the mask thickness;
and causes the ion species to be implanted to an implant depth, the implant depth being given by R p +3(LS), where LS is longitudinal straggle, and wherein the value of the implant depth is greater than 50% of the mask thickness and less than 100% of the mask thickness.

16. The method of claim 15 , wherein the first stress value corresponds to a compressive stress in a range of 200 MPa to 2 GPa.

17. The method of claim 15 , wherein the first density is 2.

Assignees

• Varian Semiconductor Equipment Ass Inc

Inventors

• Prasad Rajesh
• Liu Tzu-Yu
• Arevalo Edwin
• Mittal Deven
• Norasetthekul Somchintana
• Shim Kyuha
• Liaw Lauren
• Shimizu Takaski
• Sasaki Nobuyuki
• Muira Ryuichi
• Ito Hiro

Classifications

• H10P30/226

  at a temperature lower than room temperature · CPC title

• H10P14/69433 Primary

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P14/6518

  by introduction of substances into an already-existing insulating layer · CPC title

• H10P14/6329

  using physical ablation of a target, e.g. physical vapour deposition or pulsed laser deposition · CPC title

• H10P76/4085 Primary

  characterised by the processes involved to create the masks · CPC title