Ion beam etch without need for wafer tilt or rotation
Various embodiments herein relate to methods and apparatus for etching feature on a substrate. In a number of embodiments, no substrate rotation or tilting is used. While conventional etching processes rely on substrate rotation to even out the distribution of ions over the substrate surface, various embodiments herein achieve this purpose by moving the ion beams relative to the ion source. Movement of the ion beams can be achieved in a number of ways including electrostatic techniques, mechanical techniques, magnetic techniques, and combinations thereof.
1. An ion beam etching apparatus for etching material on a substrate, the apparatus comprising:
a reaction chamber;
a substrate support in the reaction chamber;
an ion source comprising:
a plasma region for generating and/or maintaining a plasma, and
an ion extractor positioned proximate the plasma region, the ion extractor comprising:
a first electrode and a second electrode, each of the first and second electrodes comprising a plurality of apertures therein,
sets of deflection plates provided below a lowermost electrode of the ion extractor, the lowermost electrode being one of the first and second electrodes, and
a power supply configured to supply a bias potential to one or more of the first electrode and second electrodes,
wherein the ion extractor is configured to generate a plurality of ion beams emanating from the plurality of apertures in the first and second electrodes, each ion beam having an ion beam trajectory;
an injection head positioned over the substrate support and configured to deliver reactants at a local high pressure to the substrate simultaneous with the plurality of ion beams and configured to scan across a surface of the substrate; and
a controller configured to cause:
(a) generating electric fields between the deflection plates in each set of deflection plates, and passing the ion beams through the electric fields such that the ion beam trajectories are deflected to a non-normal angle with respect to the lowermost electrode of the ion extractor, each of the ion beams trajectories being deflected at the non-normal angle to reach to the substrate during etching, and
(b) vary a strength of the electric fields between the deflection plates in each set of deflection plates to alter the ion beam trajectories such that the ion beams move with respect to the orientation of the substrate during etching.
2. The apparatus of claim 1 , wherein the deflection plates are provided in one or more arrays of parallel conductive bars.
3. The apparatus of claim 2 , wherein the deflection plates are provided in a first array of parallel conductive bars and a second array of parallel conductive bars, the first and second arrays of parallel conductive bars being oriented perpendicular to one another.
4. The apparatus of claim 1 , wherein the deflection plates are provided as conductive plates at least partially positioned within holes in an insulating plate.
5. The apparatus of claim 1 , further comprising one or more electromagnetic coils positioned outside the reaction chamber to generate a magnetic field between the lowermost electrode of the ion extractor and the substrate support, wherein in the controller is further configured to vary a strength of the magnetic field between the lowermost electrode of the ion extractor and the substrate support to alter the ion beam trajectories in a region between the ion source and the substrate support.
6. The apparatus of claim 1 , wherein the substrate support is not configured to tilt the substrate during etching.
7. The apparatus of claim 1 , wherein the substrate support is not configured rotate the substrate during etching.
8. The apparatus of claim 1 , further comprising a hollow cathode emitter electrode.
9. The apparatus of claim 1 , wherein the injection head comprises a reactant delivery region and a vacuum region that surrounds, substantially surrounds, or abuts the reactant delivery region.
10. The apparatus of claim 1 , wherein the ion beam trajectories emanating from the sets of deflection plates are deflected in a direction parallel to one another.
11. An ion beam etching apparatus for etching material on a substrate, the apparatus comprising:
a reaction chamber;
a substrate support in the reaction chamber;
an ion source comprising:
a plasma region for generating and/or maintaining a plasma, and
an ion extractor positioned proximate the plasma region, the ion extractor comprising:
a first electrode and a second electrode, each of the first and second electrodes comprising a plurality of apertures therein, and
a power supply configured to supply a bias potential to one or more of the first and second electrodes,
wherein the ion extractor is configured to generate a plurality of ion beams emanating from the plurality of apertures in the first and second electrodes, each ion beam having an ion beam trajectory;
sets of electromagnetic coils positioned around an outer periphery of the reaction chamber and configured to generate a first magnetic field proximate the ion source;
an injection head positioned over the substrate support and configured to deliver reactants at a local high pressure to the substrate simultaneous with the plurality of ion beams and configured to scan across a surface of the substrate; and
a controller configured to cause:
(a) generating the first magnetic field while generating the ion beams such that the ion beam trajectories are deflected to a non-normal angle with respect to a lowermost electrode of the ion extractor, the lowermost electrode being one of the first and second electrodes, and
(b) vary a strength of the first magnetic field proximate the ion source to alter the ion beam trajectories such that the ion beams move with respect to the orientation of the substrate during etching.
12. The apparatus of claim 11 , further comprising sets of additional electromagnetic coils positioned around an outer periphery of the reaction chamber to generate a second magnetic field between the ion source and the substrate support, the sets of additional electromagnetic coils being positioned in a lower portion of the apparatus and the sets of electromagnetic coils being positioned in an upper portion the apparatus, wherein the controller is configured to vary a strength of the second magnetic field between the ion source and the substrate support to move the ion beams with respect to the orientation of the ion source and substrate.
13. The apparatus of claim 11 , wherein the substrate support is not configured to tilt the substrate during etching.
14. The apparatus of claim 11 , wherein the substrate support is not configured rotate the substrate during etching.
15. The apparatus of claim 11 , further comprising a hollow cathode emitter electrode.
16. The apparatus of claim 11 , wherein the injection head comprises a reactant delivery region and a vacuum region that surrounds, substantially surrounds, or abuts the reactant delivery region.
17. The apparatus of claim 11 , wherein ion beams emanating from apertures in the lowermost electrode emanate parallel to one another.
18. An ion beam etching apparatus for etching material on a substrate, the apparatus comprising:
a reaction chamber;
a substrate support in the reaction chamber;
an ion source comprising:
a plasma region for generating and/or maintaining a plasma, and
an ion extractor positioned proximate the plasma region, the ion extractor comprising:
a first electrode and a second electrode, each of the first and second electrodes comprising a plurality of apertures therein, and
a power supply configured to supply a bias potential to one or more of the first and second electrodes,
wherein the ion extractor is configured to generate a plurality of ion beams emanating from the plurality of apertures in the first and second electrodes, each ion beam having an ion beam trajectory;
an injection head positioned over the substrate support and configured to deliver reactants at a local high pressure to the substrate simultaneous with the plurality of ion beams and configured to scan across a surface of the substrate; and
a controller configured to cause:
(a) generating the ion beams such that a direction of the ion beam trajectories is deflected at a non-normal angle with respect to a lowermost electrode of the ion extractor, the lowermost electrode being one of the first electrode and second electrode;
(b) altering the direction of the ion beam trajectories such that the ion beams move with respect to the orientation of the substrate during etching, wherein the direction of each ion beam trajectory is along the centerline of the ion beam; and
(c) maintaining the reaction chamber below a processing pressure, wherein the local high pressure is at least 10 times higher than the processing pressure.