Active planar autofocus
US8643835B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 2010 |
| Grant date | Feb 4, 2014 |
| Priority date | — |
| Expiry date | Dec 29, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for inspecting a depth relative to a layer using a sensor with a fixed focal plane. A focus sensor senses the surface of the substrate and outputs focus data. In setup mode the controller scans a first portion of the substrate, receives the focus data and XY data, and stores correlated XYZ data for the substrate. In inspection mode the controller scans a second portion of the substrate, receives the focus data and XY data, and subtracts the stored Z data from the focus data to produce virtual data. The controller feeds the virtual data plus an offset to the motor for moving the substrate up and down during the inspection, thereby holding the focal plane at a desired Z distance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.