Film deposition assisted by angular selective etch on a surface

Abstract

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.

What is claimed is: 
     
         1 . A method of thin film deposition on a substrate having a surface with a three dimensional feature, wherein the feature is characterized by a long axis and an angle α′ between feature wall and bottom in corner areas, the method comprising:
 rotating the substrate in a vacuum chamber by sweeping an azimuthal angle of the substrate about an initial azimuthal index angle, followed by rotating the substrate to a second azimuthal index angle, and sweeping the azimuthal angle of the substrate about the second azimuthal index angle; 
 repeating the step of rotating the substrate by sweeping a plurality of times; 
 directing a beam of particles toward a surface of the substrate for deposition thereon, at an angle relative to the plane of the substrate surface substantially equal to α′/2, wherein the directed beam of particles is substantially orthogonal to the long axis of the feature when the substrate is at the initial azimuthal index angle; 
 simultaneously directing a beam of energetic particles toward a surface of the substrate for etching thereof, at an angle relative to the plane of the substrate surface substantially equal to α′/2, wherein the directed beam of energetic particles is substantially orthogonal to the long axis of the feature at the initial azimuthal index angle. 
 
     
     
         2 . The method of  claim 1  wherein the fluxes of the beam of particles and the beam of ions provide 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 
     
     
         3 . The method of  claim 1  wherein the critical incidence deposition angle is between 55 to 75 degrees. 
     
     
         4 . The method of  claim 1  wherein the deposited dielectric film is Al2O3. 
     
     
         5 . The method of  claim 1  wherein other deposited thin film is selected from the group consisting of SiO2 and Ta2O5. 
     
     
         6 . The method of  claim 1  wherein the deposited thin film is selected from the group consisting of Al, Cr, Ti, and Ta. 
     
     
         7 . The method of  claim 1  wherein the deposited thin film is selected from the group consisting of Si and Ge. 
     
     
         8 . The method of  claim 1  wherein generating a beam of particles comprises sputtering of target material. 
     
     
         9 . The method of  claim 8  wherein generating a beam of particles comprises sputtering target material by gas ions. 
     
     
         10 . The method of  claim 9  wherein sputtering target material by gas ions comprises magnetron sputtering of target material. 
     
     
         11 . The method of  claim 10  wherein an erosion area of the target exceeds a diameter of the substrate. 
     
     
         12 . The method of  claim 9  wherein magnetron sputtering of target material comprises inert gas ions bombardment 
     
     
         13 . The method of  claim 9  wherein magnetron sputtering of target material comprises inert gas and reactive gas ions bombardment. 
     
     
         14 . The method of  claim 13  wherein the inert gas is Ar, and the reactive gas is O2. 
     
     
         15 . The method of  claim 10  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. 
     
     
         16 . The method of  claim 1  wherein generating a beam of particles comprises extracting ions from at least one plasma source. 
     
     
         17 . The method of  claim 16  wherein the plasma source comprises single beam end hall ion source. 
     
     
         18 . The method of  claim 15  wherein the plasma source comprises a multibeamlet ion beam source. 
     
     
         19 . The method of  claim 18  wherein the multibeamlet ion source comprises a gridded large area ion source. 
     
     
         20 . The method of  claim 18  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. 
     
     
         21 . The method of  claim 16  further comprising adjusting an ion beam flux uniformity by inert gas ion beam plume distribution. 
     
     
         22 . The method of  claim 21  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. 
     
     
         23 . The method of  claim 21  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.