Double-sided wafer polishing method
Provided is a double-sided polishing method of a wafer in which the wafer, which has been set in a wafer loading hole of the carrier, is compressed and held along with the carrier with an upper platen and a lower platen and the upper platen and the lower platen are rotated while supplying slurry to the wafer. The method includes: previously measuring an inclination value of a main surface of each of a plurality of carriers in the vicinity of the edge of the wafer loading hole; selecting, from among the plurality of carriers, those for which the inclination value is equal to or smaller than a threshold based on the measurement results of the inclination value; and applying the double-sided polishing to a wafer using the selected carrier.
1. A double-sided polishing method of a wafer in which, the wafer, which has been set in a wafer loading hole of a carrier, is compressed and held along with the carrier with an upper platen and a lower platen and the upper platen and the lower platen are rotated while supplying slurry to the wafer, the method comprising:
previously measuring an inclination value of a main surface of each of a plurality of carriers in the vicinity of the edge of the wafer loading hole;
selecting, from among the plurality of carriers, one or more carriers for which the inclination value is equal to or smaller than a threshold based on the measurement results of the inclination value of the main surface of each of the plurality of carriers; and
applying the double-sided polishing to the wafer using one or more of the selected carriers.
2. The double-sided polishing method of a wafer as claimed in claim 1 , wherein the threshold is set to 0.25×10 −3 .
3. The double-sided polishing method of a wafer as claimed in claim 1 , wherein the measurement range of the inclination value is set in a range between the inner peripheral edge of the wafer loading hole of the carrier and a 2 mm inward position therefrom.
4. The double-sided polishing method of a wafer as claimed in claim 1 , wherein the inclination value of the main surface of each carrier in the vicinity of the edge of the wafer loading hole is the inclination value at one position of the inner peripheral edge of the wafer loading hole or mean value of the inclination values at a plurality of positions of the inner peripheral edge of the wafer loading hole.
5. The double-sided polishing method of a wafer as claimed in claim 1 , wherein the inclination value of the main surface of each carrier in the vicinity of the edge of the wafer loading hole is an inclination of a regression line derived from the thickness distribution of the carrier within a certain range from the inner peripheral edge of the wafer loading hole.
6. The double-sided polishing method of a wafer as claimed in claim 1 , wherein each of the plurality of the carriers is constituted of a combination of a metal carrier body having a circular opening and a ring-shaped resin inserter provided along the inner periphery of the opening of the carrier body, and the width of the resin inserter is equal to or larger than 2 mm.
7. The double-sided polishing method of a wafer as claimed in claim 1 , wherein a plurality of carriers are used to apply double-sided polishing to a plurality of wafers at a time, the respective inclination values of the main surfaces of the plurality of respective carriers in the vicinity of the edge of a wafer loading hole are equal to or smaller than the threshold, and a variation in thickness among the plurality of carriers falls within ±4 μm.