What is claimed is:
1. A saw comprising:
a base;
a saw assembly connected to the base, the saw assembly comprising a pivot arm, an upper blade guard connected to the pivot arm, a motor attached to the upper blade guard, and a blade driven by the motor; and
a fence assembly attached to the base, the fence assembly comprising a fixed fence fixedly attached to the base, a movable fence movably connected to the fixed fence, the movable fence defining a first support plane, and an auxiliary fence disposed behind at least one of the fixed fence and the movable fence, the auxiliary fence defining a second support plane substantially parallel to the first support plane.
2. The saw of claim 1, further comprising a table rotatably attached to the base.
3. The saw of claim 2, wherein the saw assembly is pivotably attached to the table.
4. The saw of claim 2, further comprising a support housing connected to one of the table and the saw assembly, and at least one rail slidably connected to one of the table and the support housing,
5. The saw of claim 4, wherein the saw assembly further comprises a trunnion disposed on the at least one rail, the pivot arm being pivotably attached to the trunnion.
6. The saw of claim 1, wherein the fixed fence has a support surface.
7. The saw of claim 6, wherein the support surface is substantially parallel to an upper surface of the base.
8. The saw of claim 6, wherein the support surface is substantially perpendicular to the first support plane.
9. The saw of claim 1, wherein the fixed fence has a surface which is substantially coplanar with the first support plane.
10. A method for cutting a workpiece comprising:
providing a saw comprising a base, a saw assembly connected to the base, the saw assembly comprising a pivot arm, an upper blade guard connected to the pivot arm, a motor attached to the upper blade guard, and a blade driven by the motor, and a fence assembly attached to the base, the fence assembly comprising a fixed fence fixedly attached to the base, a movable fence movably connected to the fixed fence, the movable fence defining a first support plane, and an auxiliary fence disposed behind at least one of the fixed fence and the movable fence, the auxiliary fence defining a second support plane substantially parallel to the first support plane;
removing the movable fence from the fixed fence;
disposing the workpiece on the fixed fence and against the auxiliary fence; and
pivoting the saw assembly downwardly.
11. The method of claim 10, further comprising the step of providing a block on the base and against the fixed fence.
12. The method of claim 10, wherein the saw further comprises a table rotatably attached to the base.
13. The method of claim 12, wherein the saw assembly is pivotably attached to the table.
14. The method of claim 12, wherein the saw further comprises a support housing connected to one of the table and the saw assembly, and at least one rail slidably connected to one of the table and the support housing,
15. The method of claim 14, wherein the saw assembly further comprises a trunnion disposed on the at least one rail, the pivot arm being pivotably attached to the trunnion.
16. The method of claim 10, wherein the fixed fence has a support surface.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of fabricating a plurality of pillar-like structures on a substrate, said substrate having a plurality of protuberances formed thereon, each of the protuberances having an apex and sidewalls extending downward from an apex area, said method comprising:
forming a protective layer covering each protuberance of the plurality of protuberances with a mask material to cover at least the apex of the each protuberance;
removing the protective layer of the mask material from sidewalls of the each protuberance to expose the sidewalls and leave an island of the mask material covering the apex to form a mask on the apex of the each protuberance; and
etching each of the protuberances anisotropically with an etchant gas in a batch process to form the plurality of pillar-like structures, each pillar-like structure being etched from one of the protuberances and having a shaft extending from the mask towards the substrate, the shaft having along its length a transverse cross-sectional shape substantially defined by the shape of the mask.
2. The method of claim 1, wherein the substrate material is silicon and the etchant gas is one of a fluorine-based gas, a chlorine-based gas and a bromine-based gas.
3. The method of claim 1, wherein the etching of the each protuberance is by a plasma process.
4. The method of claim 3, wherein the plasma process is an ICP-RIE process.
5. The method of claim 4, wherein the substrate material is silicon, the mask material is Cr and the plasma is a SF6C4F8 plasma.
6. The method of claim 5, wherein the mask material Cr is evaporation coated and the removal of the coated Cr from the sidewalls is by physical sputtering with Ar ions.
7. The method of claim 4, wherein the mask material is Al and the gas used in the ICP-RIE process to remove the coated Al from the sidewalls is one of Cl2 and BCl3.
8. The method of claim 1, wherein the protective layer of the mask material on the sidewalls is removed using reactive ion etching with Ar gas.
9. The method of claim 8, wherein the protective layer of the mask material is removed from the sidewalls with Ar ions at such energy that physical process dominates the reactive process.
10. The method of claim 9, wherein the Ar ions are streamed toward the sidewalls of the protuberance at an incidence angle between 15 degrees and 40 degrees.
11. The method of claim 1, wherein the mask material is one of a metal or SiO2.
12. The method of claim 11, wherein the protective layer of SiO2 is formed by oxidization of silicon.
13. The method of claim 11, wherein the metal is selected from the group consisting of Cr, Ti, Ni, and Al.
14. The method of claim 1, wherein the protective layer of the mask material on the sidewalls is removed using a predominantly physical process.
15. The method of claim 14, wherein the protective layer of the mask material on the sidewalls is removed using one of ion milling, chemically assisted ion beam etching, or plasma etching.
16. The method of claim 1, further comprising:
covering each of the plurality of protuberances with a protective layer of second mask material after covering the plurality of protuberances with the mask material, the protective layer of the second mask material covering at least the mask material that covers the apex of the each protuberance, and
removing the protective layer of second mask material from sidewalls of the each protuberance to expose sidewalls covered by the second mask material after removing the coated mask material from the sidewalls.
17. The method of claim 16, wherein the mask material and the second mask material pair is either CrTi or AlSi.
18. The method of claim 16, wherein the second mask material is more resistive to removal than the mask material with respect to a gas ion used for removing the protective layer of the mask material from sidewalls of the pyramids.
19. The method of claim 16, wherein the protective layer of the second mask material is formed thicker than the protective layer of the mask material.
20. The method of claim 1, wherein the mask material has a selectivity of at least 1:10 with respect to the substrate material when etching with the etchant gas.
21. The method of claim 1, wherein the shaft has a shaft aspect ratio, the shaft aspect ratio being selectable by controlling etching rate and etching time at the step of etching the protuberances.
22. The method of claim 21, wherein the shaft aspect ratio is selected to be least 10.
23. The method of claim 1, wherein size of the transverse cross-sectional area is selectable by controlling size of the mask.
24. The method of claim 23, wherein the size of the mask is controlled by selecting thickness of the protective layer of the mask material covering the each protuberance and etching time applied to remove the protective layer of the mask material from the sidewalls.
25. A method of fabricating a nano-scale structure on a substrate, said substrate having at least one protuberance formed thereon, the at least one protuberance having a top surface defining the shape of the nano-scale structure and sloped sidewalls extending downward from the top surface, said method comprising:
forming a protective layer covering the at least one protuberance with mask material to cover at least the top surface;
removing the protective layer of the mask material from sidewalls of the at least one protuberance to expose the sidewalls and to form a mask covering the top surface of the at least one protuberance;
simultaneously etching the sloped sidewalls of the at least one protuberance anisotropically with an etchant gas to form substantially vertical walls extending from the mask toward the substrate, each of the substantially vertical walls being etched from one of the sloped sidewalls.
26. The method of claim 25, wherein the mask material has a selectivity of at least 1:10 with respect to the substrate material when etching using the etchant gas.
27. The method of claim 25, wherein the mask material is a metal.
28. The method of claim 25, wherein the mask material is selected from the group consisting of Cr, Ti, Ni, Cu, Al, and SiO2.
29. The method of claim 28, wherein the protective layer of SiO2 is formed by oxidization of silicon.
30. The method of claim 25, wherein the mask material is Cr and the mask material on the sloped sidewalls is removed using dry etch with Ar gas.
31. The method of claim 25, wherein the substrate material is silicon and the etchant gas is one of a fluorine-based gas, a chlorine-based gas and a bromine-based gas.
32. An array of silicon pillars on a silicon substrate, the array of silicon pillars being formed on a substrate, each of the silicon pillars being unitarily formed from the substrate, each silicon pillar comprising:
an apex spaced from the substrate,
a base integrally formed on the substrate, and
a shaft extending between the apex and the base, the shaft having a transverse cross-sectional shape substantially the same along its length,
wherein the shaft has a shaft aspect ratio that is larger than the base’s aspect ratio.
33. The array of silicon pillars of claim 32, wherein the shaft is tapered towards the apex.
34. The array of silicon pillars of claim 32, wherein the shaft is thinner in a middle section than either end of the shaft.
35. The array of silicon pillars of claim 32, wherein the shaft aspect ratio is at least 5.
36. The array of silicon pillars of claim 35, wherein the shaft aspect ratio is at least 10.
37. The array of silicon pillars of claim 32, wherein the array has a density of at least 480 silicon pillars per 100 cm2.