Method for evaluating abrasive grains, and method for manufacturing silicon wafer
AssigneeSumco Corporation
InventorYuuji Minamihata
Life of this patent
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Abstract
An evaluation method of abrasive grains used in an ingot-cutting slurry includes: an evaluation solution preparation step in which abrasive grains including polishing grains and impurities are dissolved in a solvent to prepare an evaluation solution; a sedimentation step in which a container containing the evaluation solution is left still to settle the polishing grains; a measurement step in which a turbidity of supernatant of the evaluation solution is measured using the measurement device; and an estimation step in which an amount of the impurities is estimated based on the measurement result of the turbidity of the supernatant.
Claims5
An evaluation method of abrasive grains suitable for an ingot-cutting slurry, the evaluation method comprising:
- providing abrasive grains comprising polishing grains consisting of green silicon carbide, which contributes to cutting an ingot, and
- impurities consisting of a form of tree carbon, which do not contribute to cutting the ingot:
- preparing an evaluation solution by dissolving a test portion of the abrasive grains in a solvent;
- settling the polishing grains by leaving still a container containing the evaluation solution for a period of time sufficient to settle the green silicon carbide but to leave the impurities present in a supernatant of the evaluation solution;
- measuring a turbidity of the supernatant of the evaluation solution using a turbidity measurement device;
- determining that the abrasive grains are unusable if the turbidity of the supernatant exceeds a preset level;
- and
- determining that the abrasive grains is acceptable if the turbidity of the supernatant does not exceed a predetermined level.
Dependencies are inferred from the claim text.