The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 22, 2021
Filed:
May. 15, 2018
Asml Netherlands B.v., Veldhoven, NL;
Stefan Michiel Witte, Hoofddorp, NL;
Alessandro Antoncecchi, Amsterdam, NL;
Hao Zhang, Amsterdam, NL;
Stephen Edward, Amsterdam, NL;
Paulus Clemens Maria Planken, Jaarsveld, NL;
Sebastianus Adrianus Goorden, Eindhoven, NL;
Simon Reinald Huisman, Eindhoven, NL;
Irwan Dani Setija, Utrecht, NL;
David Ferdinand Vles, Eindhoven, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A method for determining a characteristic of a feature in an object, the feature being disposed below a surface of the object is disclosed. The surface of the object is irradiated with a pulsed pump radiation beam so as to produce an acoustic wave in the object. The surface of the object is then irradiated with a measurement radiation beam. A portion of the measurement radiation beam scattered from the surface is received and a characteristic of the feature in the object is determined from at least a portion of the measurement radiation beam scattered from the surface within a measurement time period. A temporal intensity distribution of the pulsed pump radiation beam is selected such that in the measurement time period a signal to background ratio is greater than a signal to background ratio achieved using a single pulse of the pulsed pump radiation beam. The signal to background ratio is a ratio of: (a) signals generated at the surface by reflections of acoustic waves from the feature to (b) background signals generated at the surface by reflections of acoustic waves which have not reflected from the feature.