Method and system for in-line optical scatterometry

A method for 2θ scatterometry comprising:

• collimating and polarizing, using optical components, an optical beam from a laser light source to produce a collimated and polarized optical beam;
• sweeping the collimated and polarized optical beam across a surface of a parabolic mirror resulting a focal spot on a sample with a sweep of an angle of incidence of ranging from about 15° to about 65°;
• collecting, by a third optical system, light reflected from the sample at an optical detector;
• recording a signal from the optical detector giving the reflectivity vs. angle of incidence of the sample;
• and
• interpreting the recorded angular spectrum to monitor the status of the sample.

A system for 2θ scatterometry comprising:

• a laser light source configured to provide a laser beam;
• one or more control optics configured to collimate and polarize of the laser beam;
• a first optical system configured to project a focal spot of the laser beam onto a first surface of a sample with a dynamically variable angle of incidence and at a scanning speed such that a duration of an angular scan is at least fast enough that the sample has not moved by more than a spot size of the laser beam on the sample during a scan;
• a second optical system configured to collect reflected light from the sample and project collected reflected light onto an optical detector;
• and
• a digital oscilloscope configured to average and record a signal from the optical detector.