その他仕様
Flatness・Light Point Defects / Categories of Off-Orientation
Flatness
![Flatness](/sc/products/gaas/img/img_flat_01.gif)
Definitions of Flatness
TTV | Total Thickness Variation: The difference between the highest and the lowest elevation of the top surface of a clamped wafer. The back surface referenced. |
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TIR | Total Indicated Reading: The difference between the highest point above and the lowest point below the front surface referenced focal plane of a clamped wafer. 3 points on the front surface generally used. |
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LTV | Local Thickness Variation: The difference between the highest point and the lowest point within a site of the top surface of a clamped wafer. The back surface referenced. |
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PLTV | Percent LTV: Percentage of sites on a wafer within the specified LTV value. |
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Warp | The difference between the highest point above and the lowest point below the front surface referenced focal plane of an unclamped wafer. A least square fit on the front surface generally used. |
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Light Point Defects
![Light Point Defects](/sc/products/gaas/img/img_flat_06.gif)
Clockwise (EJ) / Counter Clockwise (US)
![Clockwise (EJ) / Counter Clockwise (US)](/sc/products/gaas/img/img_flat_07.gif)
Planar Representation of Cubic Form
![Planar Representation of Cubic Form](/sc/products/gaas/img/img_flat_08.gif)
Example of off-orientation
![Example of off-orientation](/sc/products/gaas/img/img_flat_09.gif)