High accuracy measurement system for focusing and leveling
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Dec 19, 2017
Issued Date -
N/A
app pub date -
Jan 15, 2016
filing date -
Nov 10, 2015
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
The present disclosure provides a high accuracy measurement system for focusing and leveling. The system determines an off-focus distance in the perpendicular direction within the exposure field and an inclination in the horizontal direction by measuring heights of four detection points on a substrate by using a four-channel detection method, thereby achieving focusing and leveling of the substrate. The detection of the substrate heights is implemented by a focusing method based on dual-channel light intensity modulation. Two superposed grating fringes are formed with phase difference of π/2. The shift can be resolved by the phase variation of corresponding fringes. According to the method, the off-focus distance can be derived. The present disclosure effectively eliminates the error due to the intensity changes caused by the fluctuations of the source or the reflectance of the substrate surface. The apparatus for focusing and leveling is easy to be implemented and has an accuracy of nanoscale.
First Claim
Family
International Classification(s)
- [Classification Symbol]
- [Patents Count]
Cited Art Landscape
Patent Citation Ranking
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully