With the development of modern precision optical systems, optical detecting system requires the accuracy of wavefront aberration to arrive to sub-nanometer level. When the incident field with polarization information, the polarization information will have a significant impact on the accuracy of measurement results by interacting with polarization-sensitive optical components in the lateral shearing interferometer. We propose the integrated interferometer wavefront sensor (IIWS) system, which is based on the traditional lateral shearing interferometer. This wavefront is sheared by a two-dimension diffraction grating in our system, the two-dimension diffraction grating is the key element to analysis the metrology performance. When using a different grating period and shearing direction, the wavefront shearing and phase shifting with polarization information will produce different error, moreover the impact will vary in the different diffraction orders. In this paper, calculation is based on the finite difference time domain (FDTD) algorithm. When calculation of different polarization state distribution of the incident field, the interaction analysis of shearing phase shifted grating and incidence light play an important role in error analysis. Finally we can get the effect of polarization for grating performance.
The semiconductor industry is aggressively pushed to produce smaller and smaller feature size from their existing base of lithography system, wavefront aberration should be derived by comparing ideal and real wavefronts at the wafer plane of a high resolution lithography system. In modern optical metrology, shearing interferometer is used more and more widely. We proposed a two-dimensional shearing interferometer, using two-dimensional Ronchi grating instead of a traditional one-dimensional grating, which can realize multidirectional and multidimensional shear. In order to further improve the detection accuracy of metrology system, vector diffraction theory is introduced. By comparing the vector and scalar light field, finally we can get the impact of vector light field on the performance of the shearing interferometer. This is for us to further improve the accuracy of detection system to provide rich information, which is crucial for the development of the lithography process.
The semiconductor industry is aggressively pushed to produce smaller and smaller feature size from their existing base
of lithography system, wavefront aberration should be derived by comparing ideal and real wavefronts at the wafer plane of a high resolution lithography system. We propose the IIWS (Integrated Interferometer Wavefront Sensor) system. On the base of traditional lateral shearing interferometer, two-dimensional phase-shifting shearing interferometry and vectorial optical analysis are used in this paper. By adjusting polarization state and polarization distribution, the metrology accuracy of the wavefront aberration of the system, which is significant for the modern semiconductor industry, is greatly increased.
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