Shallow defect analyzer

01/01/1999

Shallow defect analyzer

This optical shallow defect analyzer, the OSDA-2000, finds defects by irradiating two laser beams of different wavelengths onto a silicon wafer surface, then detecting the scattered light created by the crystal defects inside the wafer. It is designed for nondestructive detection and measurement of defects as small as 0.02 ?m inside the wafer and 0.05 ?m on the surface. Typical defects found include grown-in defects, stacking faults, oxygen precipitation, crystal originated particles, polishing and process induced damage, epitaxial layer defects, slip lines, haze, and surface particles. Crystal defects near the surface and shallow region of a silicon wafer can cause gate oxide breakdown, degradation of P-N junctions, and inferior refresh function capability of DRAMs. OSDA-2000 finds defects as small as 0.02 ?m while providing the depth information needed to distinguish between shallow-and-small and deep-and-large defects. The analyzer features a 0.5-?m measurement range with depth information and a 5-?m maximum detectable depth. Depth resolution is ?0.1 ?m. Hitachi Scientific Instruments, Mountain View, CA; ph 650/969-1100, e-mail [email protected], www.nissei.com.