- SEMI MF523 - Practice for Unaided Visual Inspection of Polished Silicon Wafer Surfaces
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 F523; previously published October 2012.
Large volumes of polished silicon wafers are produced by the semiconductor industry and consumed in the production of various devices. Surface defects are frequently deleterious to device properties.
The defects described in this Practice are visible to the unaided eye under proper lighting conditions, and the inspections are common to most consumers and producers. Therefore, it is important that a uniform inspection technique be used to aid in the manufacture of standard-quality polished silicon wafers.
This Practice covers an inspection procedure for determining the surface quality of silicon wafers that have been polished on one side.
This Practice is intended as a large-volume acceptance method and does not require use of a microscope or other optical instruments. The inspection relies heavily on the visual acuity of the operator; therefore, test results may be very operator-sensitive.
Defects visible to the unaided eye on polished wafer surfaces are categorized in three groups by the illumination geometry that best delineates them: front-surface high-intensity light, front-surface diffuse light and back-surface diffuse light. These defects originate from two sources: (1) imperfections in the silicon crystal, and (2) damage from the manufacturing process, including handling and packaging.
The inspection described generally takes place after polishing and post-polish cleaning but before packaging. Although cleaning and packaging procedures are not a part of this Practice, the inspection may be performed on a packaged product to determine the effect of such procedures on the quality of the polished wafers.
The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
Referenced SEMI Standards