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As the grinding thickness becomes thinner, cracking tends to occur on the outer edge of the wafer. To maintain a good outer edge condition during thin grinding, the wheel grit size, bond type as well as the wheel shape is important. Photos 1 and 2 are photographs that compare the outer edge of wafers that have been ground using a wheel with a different shape but with the same grit size and bond type.By selecting the correct wheel shape, an improvement in the outer edge condition is achieved.
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Photo 1: Wafer edge
Incorrect wheel shape | Photo 2: Wafer edge
Correct wheel shape |
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