BS IEC 63068‑2:2019 pdf download – Semiconductor devices – Non-destructive recognition criteria of defects in silicon carbide homoepitaxial wafer for power devices Part 2: Test method for defects using optical inspection
1 Scope This part of IEC 63068 provides definitions and guidance in use of optical inspection for detecting as-grown defects in commercially available 4H-SiC (Silicon Carbide) epitaxial wafers. Additionally, this document exemplifies optical images to enable the detection and categorization of the defects for SiC homoepitaxial wafers. This document deals with a non-destructive test method for the defects so that destructive methods such as preferential etching are out of scope in this document. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. There are no normative references in this document. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 optical inspection morphological inspection of wafers using optical imaging where an optical image sensor scans the wafer surface under a non-contact test method for obtaining features of defects, e.g. size and shape of defects 3.2 optical imaging technique for capturing, processing and analysing images of defects using light source for illumination, optical components, optical image sensor and computer systems 3.3 illumination application of light to defects and their surroundings so that they can be observed
3.4 reflective illumination illumination for observing the reflected light from defects by irradiating light onto the wafer surface 3.5 directional lighting lighting in which the light to the wafer is incident from a particular direction 3.6 diffused lighting lighting in which the irradiation direction of the light to the wafer is random 3.7 bright-field observation method of image capturing in which an optical image sensor detects both lights reflected and scattered from defects 3.8 dark-field observation method of image capturing in which an optical image sensor detects only light scattered from defects 3.9 differential interference contrast observation method of image capturing in which contrast derives from the difference in optical path between adjacent points on the wafer surface by irradiating two orthogonal polarized lights which are spatially displaced 3.1 0 polarized light observation method of image capturing in which an optical image sensor detects a polarized light using polarizing plates in a path from defects by irradiating polarized light 3.1 1 optical image sensor device to transform an optical image into digital data 3.1 2 optical component lenses, mirrors, filters and other components, which comprise an optical system and are used to capture optical images 3.1 3 image capturing process of creating a two-dimensional original digital image of defects on the wafer surface 3.1 4 original digital image digitized image taken by an optical image sensor, without performing any image processing Note 1 to entry: Original digital images are divided into pixels by a grid, and one grey level is assigned to each pixel. 3.1 5 charge-coupled device CCD light-sensitive integrated circuit that stores and displays the data for optical images