Patent ID: 8377825

Claim:
A method of reducing surface damage of a semiconductor donor wafer, comprising the steps of: (a) rotating a polishing pad, rotating the semiconductor donor wafer, applying a polishing slurry to the polishing pad, and pressing the semiconductor donor wafer and the polishing pad together; and (b) rotating the polishing pad and the semiconductor donor wafer, discontinuing the application of the polishing slurry, applying a rinsing fluid to the polishing pad, and pressing the semiconductor donor wafer and the polishing pad together, wherein step (a) followed by step (b) is carried out in sequence at least two times, and at least one of the following are reduced in at least two successive intervals of step (a): (i) a pressure at which the semiconductor donor water and the polishing pad are pressed together, (ii) a mean particle size of an abrasive within the polishing slurry, and (iii) a concentration of the polishing slurry by using the slurry diluted with water; wherein the method comprises in sequence: a first interval of step (a), where: (i) the interval lasts between about 200-600 seconds, (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 10-20 pounds per square inch, (iii) the mean particle size of the slurry is between about 60-80 nm, and (iv) the concentration of the slurry is between about 30:1-50:1; a first interval of step (b), where: (i) the interval lasts between about 20-50 seconds, and (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 1-3 pounds per square inch; a second interval of step (a), where: (i) the interval lasts between about 150-220 seconds, (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 10-15 pounds per square inch, (iii) the mean particle size of the slurry is between about 60-80 nm, and (iv) the concentration of the slurry is between about 30:1-50:1; a second interval of step (b), where: (i) the interval lasts between about 20-50 seconds, and (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 1-3 pounds per square inch; a third interval of step (a), where: (i) the interval lasts between about 200-600 seconds, (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 2-5 pounds per square inch, (iii) the mean particle size of the slurry is between about 30-40 nm, and (iv) the concentration of the slurry is between about 600:1-1000:1; and a third interval of step (b), where: (i) the interval lasts between about 10-20 seconds, and (ii) the pressure at which the semiconductor donor wafer and the polishing pad are pressed together is between about 1-3 pounds per square inch.