1. A method of polishing a substrate, comprising:
holding the substrate on a polishing pad with a polishing head;
creating relative motion between the substrate and the polishing pad to polish a layer on the substrate;
directing a light beam from the side of the substrate with the layer towards the substrate to cause the light beam to impinge on the layer being polished;
receiving light reflected from the substrate at a detector to generate an interference signal; and
computing a measure of uniformity of the thickness of the layer from the interference signal.
2. The method of claim 1, wherein creating relative motion between the substrate and the polishing pad includes rotating the polishing head.
3. The method of claim 2, wherein creating relative motion between the substrate and the polishing pad includes rotating a platen supporting the polishing pad.
4. The method of claim 1, further comprising generating relative lateral motion between the light beam and the carrier head.
5. The method of claim 4, wherein generating relative lateral motion between the light beam and the carrier head comprises laterally translating the carrier head across the polishing pad.
6. The method of claim 1, wherein the light beam is a laser beam.
7. The method of claim 1, further comprising:
comparing the measure of uniformity to a reference; and
generating an alert when the measure of uniformity diverges from the reference by more than a predetermined amount.
8. The method of claim 1, wherein the interference signal includes a low frequency component and wherein computing the measure of uniformity includes measuring an amplitude of the low frequency component.
9. The method of claim 8, further comprising filtering the interference signal to obtain the low frequency component.
10. The method of claim 8, wherein the interference signal includes a high frequency component and wherein computing the measure of uniformity includes measuring an amplitude of the high frequency component.
11. The method of claim 10, further comprising filtering the interference signal to obtain the high frequency component.
12. The method of claim 10, wherein computing the measure of uniformity includes calculating a ratio of the amplitude of the high frequency component and the amplitude of the low frequency component.
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 polishing head provided at least with an annular rigid ring, a rubber film bonded to the rigid ring with a uniform tension, a mid plate joined to the rigid ring and forming a space together with the rubber film and the rigid ring, and an annular template provided concentrically with the rigid ring in a peripheral portion on a lower face part of the rubber film and having an outer diameter larger than an inner diameter of the rigid ring, in which a pressure of the space can be changed by a pressure adjustment mechanism, a back face of a work is held on the lower face part of the rubber film, and a surface of the work is brought into sliding contact with the polishing pad attached onto a turn table for performing polishing, wherein an inner diameter of the template is smaller than an inner diameter of the rigid ring, and a ratio between an inner diameter difference between the rigid ring and the template and a difference between the inner diameter and an outer diameter of the template is 26% or more and 45% or less.
2. The polishing head according to claim 1, wherein the inner diameter of the template is larger than the outer diameter of the work by 0.5 mm or more and 2.0 mm or less, and the outer diameter of the template is larger than the outer diameter of the work by 10% or more and 20% or less.
3. The polishing head according to claim 1, wherein the work to be polished is a silicon single crystal wafer with a diameter of 300 mm or more.
4. The polishing head according to claim 2, wherein the work to be polished is a silicon single crystal wafer with a diameter of 300 mm or more.
5. The polishing head according to claim 1, wherein, when the work is held by the polishing head, a thickness of the template is set so that a position of a lower face of the work is lower than a position of 60 \u03bcm above the lower face of the template and higher than a position of 5 \u03bcm below the lower face of the template.
6. The polishing head according to claim 2, wherein, when the work is held by the polishing head, a thickness of the template is set so that a position of a lower face of the work is lower than a position of 60 \u03bcm above the lower face of the template and higher than a position of 5 \u03bcm below the lower face of the template.
7. The polishing head according to claim 3, wherein, when the work is held by the polishing head, a thickness of the template is set so that a position of a lower face of the work is lower than a position of 60 \u03bcm above the lower face of the template and higher than a position of 5 \u03bcm below the lower face of the template.
8. The polishing head according to claim 4, wherein, when the work is held by the polishing head, a thickness of the template is set so that a position of a lower face of the work is lower than a position of 60 \u03bcm above the lower face of the template and higher than a position of 5 \u03bcm below the lower face of the template.
9. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 1 as a polishing head for holding the work.
10. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 2 as a polishing head for holding the work.
11. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 3 as a polishing head for holding the work.
12. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 4 as a polishing head for holding the work.
13. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 5 as a polishing head for holding the work.
14. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 6 as a polishing head for holding the work.
15. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 7 as a polishing head for holding the work.
16. A polishing apparatus used when a surface of a work is polished and provided at least with a polishing pad attached onto a turn table, a polishing agent supply mechanism for supplying a polishing agent onto the polishing pad, and the polishing head according to claim 8 as a polishing head for holding the work.