Film deposition assisted by angular selective etch on a surface
View Patent ↗An ion etch assisted deposition apparatus deposits a thin film upon a substrate having a three dimensional feature, using an ion etching source and deposition source arranged at similar angles relative to the substrate and at an angle α relative to each other. The angle α is selected to be substantially equal the supplement of the angle α′ formed between the three dimensional feature on the substrate and the substrate surface. In this configuration the relative flux of energetic etch ions and deposition atoms is adjusted to prevent the growth of poor quality deposited material.
1. A method of thin film deposition of a conforming film on a substrate having a surface with a three dimensional feature the method comprising:
rotating the substrate in a vacuum chamber;
directing a beam of particles toward a surface of the substrate for deposition thereon;
simultaneously directing a beam of energetic particles toward a surface of the substrate for etching thereof;
wherein the beam of particles for deposition has an axis and the beam of particles for etching has an axis and said axes are arranged at an angular separation α relative to each other, wherein angular separation α is the supplementary angle of an angle α′ formed between the three dimensional feature and the substrate surface, and wherein the substrate is tilted to an angle of approximately α′/2 relative to the axis of the beam of particles for deposition and the substrate is tilted to an angle of approximately α′/2 relative to the axis of the beam of particles for etching; and
wherein the fluxes of the beam of particles and the beam of ions provide a net positive deposition rate in areas of the substrate where the incidence angle of said beams is less than a critical incidence angle, while also providing an average etch rate of the substrate surface that is equal or higher than the average deposition rate of said particles when the incidence angles of said beams is greater than a critical incidence deposition angle.
2. The method of claim 1 wherein the critical incidence deposition angle is between 55 to 75 degrees.
3. The method of claim 1 wherein the deposited dielectric film is Al2O3.
4. The method of claim 1 wherein other deposited thin film is selected from the group consisting of SiO2 and Ta2O5.
5. The method of claim 1 wherein the deposited thin film is selected from the group consisting of Al, Cr, Ti, and Ta.
6. The method of claim 1 wherein the deposited thin film is selected from the group consisting of Si and Ge.
7. The method of claim 1 wherein a beam of particles for deposition is generated by sputtering of target material.
8. The method of claim 7 wherein a beam of particles for deposition is generated by sputtering target material by gas ions.
9. The method of claim 8 wherein sputtering target material by gas ions comprises magnetron sputtering of target material.
10. The method of claim 9 wherein an erosion area of the target exceeds a diameter of the substrate.
11. The method of claim 8 wherein magnetron sputtering of target material comprises inert gas ions bombardment.
12. The method of claim 8 wherein magnetron sputtering of target material comprises inert gas and reactive gas ions bombardment.
13. The method of claim 12 wherein the inert gas is Ar, and the reactive gas is O2.
14. The method of claim 9 further comprising collimating particles with a physical collimator located 1-3 inches from the target in plane of target, between the target and the substrate.
15. The method of claim 1 wherein the beam of energetic particles is generated by extracting ions from at least one plasma source.
16. The method of claim 15 wherein the plasma source comprises single beam end hall ion source.
17. The method of claim 14 wherein the plasma source comprises a multibeamlet ion beam source.
18. The method of claim 17 wherein the multibeamlet ion source comprises a gridded large area ion source.
19. The method of claim 17 wherein the multibeamlet ion source comprises multiple end hall ion sources with outlets located in the same plane and with the same axis as single source.
20. The method of claim 15 further comprising adjusting an ion beam flux uniformity by adjusting the inert gas ion beam plume distribution.
21. The method of claim 20 wherein adjusting the inert gas ion beam plume distribution comprises tilting the ion source with respect to an axis normal to the plane of the substrate.
22. The method of claim 20 wherein adjusting the inert gas ion beam plume distribution comprises offsetting a central axis of the ion source relative to a center point of the substrate.