Development of Calibration-Free Imaging Ellipsometry Using Dual-Rotation of Polarizer and Analyzer

Abstract

Imaging ellipsometry is developed in the dual-rotation mode of a polarizer and an analyzer. In this system, the polarizer and analyzer are rotated by a stepping motor at 1:1 ratio and the offset between the azimuths of both elements is kept constant. For data reduction, a two-dimensional array detector collects multiple intensity images during rotation and waveform analysis is performed for each pixel. This system generates second and fourth harmonics in intensity waveform and {Δ, Ψ} images are deduced from the amplitudes of these harmonics without considering their phases, which leads to calibration-free imaging ellipsometry. This system works well with an offset between two elements but it becomes less susceptible to an offset-setting error with a smaller offset. Besides the ease of operation, this system is simple to construct as no complicated control mechanism is required for each component.

Optical Investigation of Deep Ultraviolet Degradation of Pellicles

“…11) An imaging ellipsometer operated at 520 nm was also used to investigate the microscopic uniformity of a pellicle upon exposure. 12) This ellipsometer employs an objective lens and a two-dimensional array detector in a single-wavelength ellipsometer configuration. Thus, it can be used to acquire microscopic images of ellipsometric parameters in approximately 10 s. In other words, functionally, it is a single-wavelength ellipsometer with a micrometer level lateral resolution.…”

Comparison null imaging ellipsometry using polarization rotator

“…In IE, imaging lenses and a two-dimensional sensor are integrated into an ellipsometer to acquire ellipsometric images in a small area of a surface. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] One of the popular operating principles of IE is based on the null principle, where two ellipsometric angles ðÁ; ÉÞ are obtained from the azimuths of the polarizer, compensator, and analyzer at which the extinction of the reflected light from the sample occurs. [18][19][20][21][22][23][24][25][26] However, null IE is not designed to obtain ðÁ; ÉÞ images over the entire points of an imaging area.…”

Fast Imaging Ellipsometer Using a LiNbO3 Electrooptic Crystal

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] According to application needs, IEs with different measurement methods, based on single-point ellipsometry, have been developed and employed. Null ellipsometry, 14) rotating polarizer/analyzer ellipsometry, 23,29) and rotating compensator ellipsometry 26) are used for an entire view measurement. Scanning imaging ellipsometry 17,20,27) maps the ellipsometric image by moving the samples.…”