Apparatus and methods for optically inspecting a sample for anomalies
US6833913B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2002 |
| Grant date | Dec 21, 2004 |
| Priority date | — |
| Expiry date | Jun 24, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed are methods and apparatus for detecting a relatively wide dynamic range of intensity values from a beam (e.g., scattered light, reflected light, or secondary electrons) originating from a sample, such as a semiconductor wafer. In other words, the inspection system provides detected output signals having wide dynamic ranges. The detected output signals may then be analyzed to determine whether defects are present on the sample. For example, the intensity values from a target die are compared to the intensity values from a corresponding portion of a reference die, where a significant intensity difference may be defined as a defect. In a specific embodiment, an inspection system for detecting defects on a sample is disclosed. The system includes a beam generator for directing an incident beam towards a sample surface and a detector positioned to detect a detected beam originating from the sample surface in response to the incident beam. The detector has a sensor for detecting the detected beam and generating a detected signal based on the detected beam and a non-linear component coupled to the sensor. The non-linear component is arranged to generate a non-linear detected sig…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.