Terms, definitions and characteristics
| Term | Ref.symbol | Definitions |
|---|---|---|
| Material | ||
| Synthetic quartz crystal |
SQC | Synthetic quartz crystal with quality grade C or better, inclusion density Grade II and etch channel density Grade 2, ( according EN/IEC 60758 ) |
| Lithium Niobate | LN | Crystal material with Curie temperature within specified value and with single domain structure by polarization process |
| Lithium Tantalate | LT | Crystal material with Curie temperature within specified value and with single domain structure by polarization process |
| Dimensions | ||
| Diameter | D | Diameter of circular portion of wafer in millimeters or inchs |
| Thickness | T | Thickness at the center of wafer measured by thickness meter having an accuracy of 1 µm |
| Orientation flat | OF | Cut surface intersecting around wafer for indication of wafer orientation |
| Index flat ( secondary ) |
IF | Cut surface intersecting around wafer for additional indication of wafer orientation (according customer specification) |
| Bevel | A round shaping of wafer on the edge | |
| Surface orientation | Crystallographical orientation of the axis perpendicular to the surface of wafer | |
| Surface characteristics |
||
| Flatness | TV5 | Thickness variation of wafer for five points (one at the center and 4 points at the edge) |
| LTV | Local thickness variation | |
| Bow | Bending deformation of wafer | |
| Warp | Deformation of wafer, definition see IEC 62276, Ed.1 | |
| Defects | Perturbations on polished ( working ) wafer surface. Detail definitions of defects, see IEC 62276. |
|
| Back surface roughness |
Ra | Definition according ISO 468, value according customer specification Alternative: specification by abrasive grain size. |