- SEMI MF950 - Test Method for Measuring the Depth of Crystal Damage of a Mechanically Worked Silicon Wafer Surface by Angle Polished and Defect Etching
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on February 1, 2018. Available at www.semiviews.org and www.semi.org in July 2018; originally published by ASTM International as ASTM F950; previously published September 2012.
The principal application of this Test Method is for determining the depth of damage of the nonpolished back surface of a silicon wafer that has had intentionally added work damage. This Test Method is intended for use in process control where each individual location is responsible to determine the internal repeatability to its satisfaction.
This Test Method provides a means for measuring the depth of mechanical damage in silicon wafers in the range from 5 to 200 µm.
This Test Method can be used for process control or research and development purposes. It is not recommended for use in material acceptance.
This Test Method covers a technique to measure the depth of damage, on or beneath the surface of silicon wafers prior to any heat treatment of the wafer. Such damage results from mechanical surface treatments such as sawing, lapping, grinding, sandblasting, and shot peening.
The damage is revealed by a preferential etch that removes silicon in the region of the deformation. Preferential etching occurs because the chemical potential in the region of the deformation is changed by the stress fields associated with the deformation. The depth of damage is expressed in micrometers.
The measurement is destructive because a specimen is prepared from a section of a silicon wafer.
Depth of damage can be measured in the range of 5 to 200 μm using this method.
Referenced SEMI Standards
SEMI C28 — Specification and Guide for Hydrofluoric Acid
SEMI M59 — Terminology for Silicon Technology
SEMI MF672 — Test Method for Measuring Resistivity Profiles Perpendicular to the Surface of a Silicon Wafer Using a Spreading Resistance Probe
SEMI MF1809 — Guide for Selection and Use for Etching Solutions to Delineate Structural Defects in Silicon