Edge etched silicon wafers
View Patent ↗The present disclosure generally relates to the manufacture of silicon wafers, and more particularly to edge etching apparatus and methods for etching the edge of a silicon wafer.
1. A silicon wafer comprising a central axis, a front surface and a back surface that are generally perpendicular to the central axis, a radius, R, extending from the central axis to a point along the peripheral edge, a point along the peripheral edge nearest the central axis, edge portions of the front and back surfaces of the wafer that extend from the nearest peripheral edge point to a point between the nearest peripheral point and the central axis and no more than about 15 mm from the nearest peripheral edge point, and central portions of the front and back surfaces of the wafer that extend from the point between the nearest peripheral point and the central axis and the central axis; wherein:
the front and back surfaces of the wafer have a total thickness variation of at least 20 microns;
the central portions of the front and back surfaces of the wafer have a surface roughness of at least about 0.3 μm Ra; and
the edge portions of the front and back surfaces of the wafer have a surface roughness of less than about 0.3 μm Ra, the central portions of the front and back surfaces of the wafer having a surface roughness greater than the surface roughness of the edge portions of the front and back surface of the wafer.
2. The silicon wafer of claim 1 wherein the front and back surfaces of the wafer have a total thickness variation of at least about 25 microns.
3. The silicon wafer of claim 1 wherein the front and back surfaces of the wafer have a total thickness variation of at least about 35 microns.
4. The silicon wafer of claim 1 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 0.3 to about 2.5 μm Ra.
5. The silicon wafer of claim 1 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 0.7 to about 2 μm Ra.
6. The silicon wafer of claim 1 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 1 to about 1.5 μm Ra.
7. The silicon wafer of claim 1 wherein the edge portions of the front and back surfaces of the wafer have a surface roughness of from about 0.2 μm Ra.
8. The silicon wafer of claim 1 wherein the edge portions of the front and back surfaces of the wafer have a surface roughness of from about 0.1 μm Ra.
9. The silicon wafer of claim 1 wherein R is at least about 150 mm.
10. The silicon wafer of claim 1 wherein the peripheral edge comprises two bevels and an apex.
11. The silicon wafer of claim 1 wherein the peripheral edge is rounded.
12. A silicon wafer comprising a central axis, a front surface and a back surface that are generally perpendicular to the central axis, a radius, R, extending from the central axis to a point along the peripheral edge, a point along the peripheral edge nearest the central axis, edge portions of the front and back surfaces of the wafer that extend from the nearest peripheral edge point to a point between the nearest peripheral point and the central axis, and central portions of the front and back surfaces of the wafer that extend from the point between the nearest peripheral point and the central axis and the central axis; wherein:
the front and back surfaces of the wafer have a total thickness variation of at least 20 microns;
the central portions of the front and back surfaces of the wafer have a surface roughness of at least about 0.3 μm Ra; and
the edge portions of the front and back surfaces of the wafer have a surface roughness of less than about 0.2 μm Ra.
13. The silicon wafer of claim 12 wherein the front and back surfaces of the wafer have a total thickness variation of at least about 25 microns.
14. The silicon wafer of claim 12 wherein the front and back surfaces of the wafer have a total thickness variation of at least about 35 microns.
15. The silicon wafer of claim 12 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 0.3 to about 2.5 μm Ra.
16. The silicon wafer of claim 12 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 0.7 to about 2 μm Ra.
17. The silicon wafer of claim 12 wherein the central portions of the front and back surfaces of the wafer have a surface roughness of from about 1 to about 1.5 μm Ra.
18. The silicon wafer of claim 12 wherein the edge portions of the front and back surfaces of the wafer have a surface roughness of from about 0.1 μm Ra.
19. The silicon wafer of claim 12 wherein R is at least about 150 mm.
20. The silicon wafer of claim 12 wherein the peripheral edge comprises two bevels and an apex.
21. The silicon wafer of claim 12 wherein the peripheral edge is rounded.