Spot grid array imaging system
US6639201B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2001 |
| Grant date | Oct 28, 2003 |
| Priority date | — |
| Expiry date | Mar 1, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8806
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A high data-rate spot-grid array imaging system is provided that compensates for stage vibrations and overcomes the severe linearity requirements of prior art systems. Embodiments include an imaging system with a two-dimensional and periodic array of lenses, each lens imaging a spot in an object plane, such as a semiconductor substrate to be inspected, upon an image plane to image a two-dimensional and periodic array of spots. A sensor is provided in a conjugate image plane with a two-dimensional and periodic array of readout elements, each collecting the signal from one of the spots. A mechanical system moves the substrate in a direction which is nearly parallel to an axis of the array of spots such that as the substrate is moved across the spot array in the scan direction (the y-direction) the spots trace a path which leaves no gaps in the mechanical cross-scan direction (the x-direction). A compensator, such as a servo or a movable mirror, compensates for mechanical inaccuracies in the moving stage, thereby increasing imaging accuracy. In other embodiments, the motion of the mechanical system provides a small overlap between coverage areas of lenses of the lens array in consecut…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.