Laser imaging system for inspection and analysis of sub-micron particles
US5479252A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1993 |
| Grant date | Dec 26, 1995 |
| Priority date | — |
| Expiry date | Jun 17, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/006
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A laser imaging system is used to analyze defects on semiconductor wafers that have been detected by patterned wafer defect detecting systems (wafer scanners). The laser imaging system replaces optical microscope review stations now utilized in the semiconductor fab environment to examine detected optical anomalies that may represent wafer defects. In addition to analyzing defects, the laser imaging system can perform a variety of microscopic inspection functions including defect detection and metrology. The laser imaging system uses confocal laser scanning microscopy techniques, and operates under class 1 cleanroom conditions and without exposure of the wafers to operator contamination or airflow. Unlike scanning electron microscopes (SEMs) that have previously been used for defect analysis, the laser imaging system will not damage samples or slow processing, costs significantly less to implement than an SEM, can produce a three dimensional image which provides quantitative dimensional information, and allows sub-surface viewing of defects lying beneath dielectric layers. The laser imaging system is adaptable to cluster or in-situ applications, where examination of defects or stru…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.