MX 102-12
	300 mm Wafer Thickness and Flatness Gauge
	Abstract
	Based on a turntable used with 4" to 8" wafers, the MX 102-12 yields four radial profiles, each consisting of 300 thickness values. The number of profiles can be increased to cover the entire area of the wafer. The gauge uses one pair of capacitive sensors having a resolution of 10 nanometers. Within a few seconds, it can be adapted to different thickness ranges. Before every scan, the gauge recalibrates itself automatically by means of a certified gauge block.
	Extended Range Mode
	The MX 102-12 was originally designed for thickness measurements after the grinding or lapping stages. In these cases, the TTV of the wafers is small, and the resolution the instrument is supposed to have is high. There are other process stages, however, especially after cutting or after backside grinding, where a higher thickness range is more important than a resolution of some nanometers. In the PC controlled setup, the measuring range of the instrument can be set to normal or extended.
	SCAN8XN
	The standard four radial scans are sufficient for many applications. Theoretically, it might be possible to increase the number of scans so that almost 50 percent of the wafer area could be covered. The remaining area, however, lies in the 'shadow' of the four wafer supports. A simple additional movement solves this problem. After the first part of the measurement cycle, the wafer is raised and held by two pneumatic stamps while the turntable beneath the wafer performs a rotational movement of 45 degrees. After the wafer is lowered back to the supports and reclamped by the vacuum chuck, the second part of the measurement cycle may begin, which will cover the remaining part of the wafer area. This, of course, increases the measuring time correspondingly.
	The additionally offered measuring program SCAN8XN provides a compromise between resolution and throughput: the second scan cycle has an offset of 22.5 degrees, yielding eight cross scans with a total number of about 2300 measuring points. A simple three-dimensional graphic representation gives a global impression of the wafer's shape.
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