Method and apparatus for producing and measuring dynamically focussed, steered, and shaped oblique laser illumination for spinning wafer inspection system

摘要

A method and apparatus for producing high frequency dynamically focused oblique laser illumination for a spinning wafer inspection system. The focus is changed by changing the beam direction incidence angle so as to bring focal spot onto the wafer surface.;Disclosed herein is a system and method for automatic beam shaping (i.e., spot size) and steering (i.e., position) for a spinning wafer inspection system, combined into a single module. Also disclosed is a method and system for measuring the beam position/size/shape and angle with sufficient resolution to make corrections using feedback from the monitor.

主权项

1. A spinning wafer inspection system for inspecting a wafer surface including a high frequency fast auto focus mechanism, wherein;
said high frequency fast auto focus mechanism dynamically adjusts tilt of a rotatable mirror to bring and maintain a laser beam focal spot onto said wafer surface; and; wherein there are no focusing optics in said laser beam's optical path between said rotatable mirror and said wafer surface; wherein said high frequency fast auto focus mechanism comprises a control system configured to utilize feedback from position-sensitive detectors to dynamically calculate actual beam position, actual position of said wafer surface, and intercept point between the beam and said wafer surface at any sampling time.