What is claimed is:
1. A method of grinding wafers, said method comprising:
providing a cut wafer having initial thickness variations between first and second wafer surfaces;
applying a polymer to said first surface to form a substantially smooth outer surface;
positioning said wafer on a grinding tool; and
grinding said second surface to form a substantially planar second surface.
2. The method as in claim 1 wherein said applying said polymer comprises applying a liquid polymer to said first surface.
3. The method as in claim 2 further comprising curing said liquid polymer before grinding said second surface.
4. The method as in claim 3 wherein said curing comprises a heat cure.
5. The method as in claim 3 wherein said curing comprises an ultraviolet light cure.
6. The method as in claim 3 wherein said curing comprises a cure with electromagnetic energy.
7. The method as in claim 1 wherein said applying said polymer forms a polymer film having a thickness between about five (5) microns and about thirty (30) microns.
8. The method as in claim 1 wherein said positioning comprises placing said outer surface on a grinding tool platen.
9. The method as in claim 1 further comprising grinding said polymer and said first surface.
10. The method as in claim 9 further comprising cleaning said second surface prior to said grinding said polymer and said first surface.
11. The method as in claim 9 wherein said grinding said second surface, said polymer and said first surface substantially removes said thickness variations.
12. The method as in claim 9 wherein said grinding removes substantially all of said polymer, and a portion of said first and second surfaces.
13. The method as in claim 1 further comprising:
cleaning said wafer after grinding said second surface;
repositioning said wafer on said grinding tool to expose said outer surface; and
grinding said polymer and said first surface.
14. The method as in claim 1 further comprising applying said polymer while simultaneously rotating said wafer.
15. A method of preparing a substrate for grinding operations, said method comprising:
providing a substrate having first and second surfaces;
applying a curable liquid to said first surface;
curing said curable liquid to form a substantially smooth outer surface;
positioning said outer surface on a grinding tool platen to expose said second surface to a grinder.
16. A wafer grinding apparatus, comprising:
an applicator for applying a curable liquid to a wafer surface;
a curer for curing said curable liquid;
a platen for holding said wafer; and
a grinder for grinding said wafer surface.
17. The apparatus as in claim 16 further comprising a rotation device coupled to said platen for rotating said wafer.
18. The apparatus as in claim 16 wherein said applicator comprises a spin on applicator and said curable liquid comprises a liquid polymer.
19. The apparatus as in claim 16 wherein said curer comprises an ultraviolet light source.
20. The apparatus as in claim 16 wherein said curer comprises an electromagnetic energy source.
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 device for estimating a frequency offset of a received signal, comprising:
a plurality of phase estimation units, each of the plurality of phase estimation units adapted for receiving one of a plurality of data parts of the received signal and estimating a phase caused by frequency offset from the received data part, wherein the plurality of data parts comprises payload data and known symbols in the received signal; and
a frequency offset estimation unit for estimating the frequency offset from a plurality of phases estimated by the plurality of phase estimation units.
2. The device according to claim 1, wherein each of the plurality of phase estimation units comprises:
a reconstruction unit for reconstructing a data part by remodulating and filtering it and outputting a reconstructed data part;
a combining unit for generating a product of the data part with a conjugation of the reconstructed data part; and
a phase calculation unit for calculating the phase from the product.
3. The device according to claim 2, wherein each of the plurality of phase estimation units further comprises a gating unit for gating the product generated by the combining unit with a predetermined threshold.
4. The device according to claim 2, wherein each of the plurality of phase estimation units further comprises an averaging unit for averaging a plurality of products generated by the combining unit.
5. The device according to claim 3, wherein each of the plurality of phase estimation units further comprises an averaging unit for averaging a plurality of products gated by the gating unit.
6. The device according to claim 1, wherein the device is implemented in a Global System for Mobile Communications (GSM) system.
7. The device according to claim 1, wherein the known symbols comprise left and right tail symbols.
8. The device according to claim 1, wherein the known symbols further comprise a training sequence code.
9. A method for estimating a frequency offset of a received signal, comprising:
estimating a plurality of phases caused by the frequency offset from a plurality of data parts of the received signal, wherein the plurality of data parts comprises payload data and known symbols in the received signal; and
estimating the frequency offset from the estimated plurality of phases.
10. The method according to claim 9, wherein estimating the plurality of phases comprises:
reconstructing the plurality of data parts by remodulating and filtering the plurality of data parts and outputting a plurality of reconstructed data parts;
generating a product of the plurality of the data parts with a conjugation of the plurality of reconstructed data parts; and
calculating the plurality of phases from the product generated for each of the plurality of the data parts.
11. The method according to claim 10, wherein estimating the plurality of phases further comprises gating the product generated for each of the plurality of the data parts with a predetermined threshold.
12. The method according to claim 10, wherein estimating the plurality of phases further comprises averaging a plurality of products generated for each of the plurality of the data parts.
13. The method according to claim 11, wherein estimating the plurality of phases further comprises averaging a plurality of products gated for each of the plurality of the data parts.
14. The method according to claim 9, wherein the method is implemented in a Global System for Mobile Communications (GSM) system.
15. The method according to claim 9, wherein the known symbols comprise right and left tail symbols.
16. The method according to claim 9, wherein the known symbols further comprise a training sequence code.
17. A computer program product comprising program codes, which, when run on a computer, executed in the computer to implement a method, comprising:
estimating a plurality of phases caused by the frequency offset from a plurality of data parts of the received signal, wherein the plurality of data parts comprises payload data and known symbols in the received signal; and
estimating the frequency offset from the estimated plurality of phases.
18. The computer program product according to claim 17, the method further comprising:
reconstructing the plurality of data parts by remodulating and filtering the plurality of data parts and outputting a plurality of reconstructed data parts;
generating a product of the plurality of the data parts with a conjugation of the plurality of reconstructed data parts; and
calculating the plurality of phases from the product generated for each of the plurality of the data parts.
19. The computer program product according to claim 18, wherein estimating the plurality of phases further comprises gating the product generated for each of the plurality of the data parts with a predetermined threshold.
20. The computer program product according to claim 18, wherein estimating the plurality of phases further comprises averaging a plurality of products generated for each of the plurality of the data parts.