3D information or surface topography, an accurate method of measuring, determining and isolating defects.
These three images are screenshots taken from the measurement of different parts of a semiconductor die taken on the Zygo NewView 6300. A magnification of 20X (10x objective coupled to a 2x zoom) provided detailed surface topography of the semiconductor device with a lateral resolution close to 1 micron. In this application the aim was to identify defects in the 3D structure of the device against a reference structure which was defect free. As many defects in such devices are not confined to just variations in reflected light the use of 3D information or surface topography is a far more accurate method of determining and isolating defects.
Figure 1
This measurement shows an isolated D shaped structure with a raised surface defect shown as a line on the intensity image map. By taking a 2D profile the height of this defect approximately 1 micron can be clearly seen.
Figure 2
Measurement of the die in this particular area is seen to be free of defects and can be used as a reference 3D map.
Figure 3
This measurement shows two sets of finger like or rib structures where the set on the left show that material has coalesced to create a defect. This is particularly evident when examining the 2D surface profile created by placing a snap line across the 3D topographic data.