On-axis focus sensor and method
US9594230B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2012 |
| Grant date | Mar 14, 2017 |
| Priority date | — |
| Expiry date | Mar 24, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/127
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A focus height sensor in an optical system for inspection of semiconductor devices includes a sensor beam source that emits a beam of electromagnetic radiation. A reflector receives the beam of electromagnetic radiation from the sensor beam source and directs the beam toward a surface of a semiconductor device positioned within a field of view of the optical system. The reflector is positioned to receive at least a portion of the beam back from the surface of the semiconductor device to direct the returned beam to a sensor. The sensor receives the returned beam and outputs a signal correlating to a position of the surface within the field of view along an optical axis of the optical system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.