| 摘要 |
PROBLEM TO BE SOLVED: To prevent a water from being scratched at its underside or being cracked in the lapping. SOLUTION: Each carrier 13 is perforated with a plurality of through holes 19 in its thickness direction. The total opening area of the through holes 19 is set between 0.8% and 20% of the whole surface area of the carrier 13. Slurry is fed through the through holes 19 to the underside of wafers 14. Opening area ratios below 0.8% insufficiently feed slurry to the underside of the wafers 14, causing scratches on their underside, while those over 20% lower the mechanical strength of the carrier 13, resulting in an imperfect hold of the wafers 14 and thus their cracks. The opening area of each through hole 19 is preferably not larger than 60cm<2> . The plural through holes 19 are dispersively formed over the whole surface of the carrier 13 in a uniform way. The slurry used in the lapping includes FO. That arrangement prevents scratches on the wafers 14 and their cracks. |
