Enhanced high aspect ratio etch performance using accelerated neutral beams derived from gas-cluster ion beams
A method of processing a trench, via, hole, recess, void, or other feature that extends a depth into a substrate to a base or bottom and has an opening with high aspect ratio (into depth from opening to base or bottom divided by minimum space of the trench therebetween) by irradiation with an accelerated neutral beam derived from an accelerated gas cluster ion beam for processing materials at the base or bottom of the opening.
1. A method for processing a trench structure having a proximate opening and a distal base or bottom material therein having an exposed surface deep within the trench accessible through said opening via the trench structure with an aspect ratio, within a range 5:1 to 200:1:
providing a reduced pressure chamber;
forming a gas cluster ion beam comprising gas cluster ions within the reduced pressure chamber;
accelerating and focusing the gas cluster ions to form an accelerated and focused gas cluster ion beam along a beam path within the reduced pressure chamber;
promoting fragmentation and/or dissociation of at least a portion of the accelerated gas cluster ions along the beam path by increasing the range of velocities of ions in the accelerated gas cluster ion beam while substantially maintaining focus of the gas cluster ion beam;
removing charged particles from the beam path to form an accelerated and focused neutral beam along the beam path in the reduced pressure chamber;
holding a workpiece constituting all or part of the base or bottom material of the trench structure in the beam path to direct the neutral beam path through the trench structure opening and to the exposed surface of the base or bottom material; and
treating the base or bottom material exposed surface by irradiating the exposed surface with the accelerated and focused neutral beam.
2. The method of claim 1 , wherein at least a portion of the base or bottom material is removed by the step of treating.
3. The method of claim 2 wherein the at least a portion of the base or bottom material is removed by etching, sputtering, reactive etching, or inert etching.
4. The method of claim 1 , wherein the step of treating grows an epitaxial layer on the base or bottom material.
5. The method of claim 1 , wherein the base or bottom material is at least partially crystalline, and further wherein the step of treating results in formation of an amorphized layer.
6. The method of claim 4 , wherein the treated base or bottom material has exposed dangling bonds.
7. The method of claim 5 , further wherein the amorphized layer is an oxidized amorphous layer.
8. The method of claim 1 , wherein the step of treating deposits a dissimilar material onto the base or bottom material.
9. The method of claim 1 , wherein the irradiating step further includes the step of directing or aligning the accelerated neutral beam with a feature of the trench to facilitate anisotropic processing of the base or bottom surface.
10. A semiconductor material with a surface as processed by treatment per the method of claim 1 .
11. A dielectric material with a surface as processed by treatment per the method of claim 1 .
12. A metallic material with a surface as processed by treatment per the method of claim 1 .
13. A ceramic material with a surface as processed by treatment per the method of claim 1 .