TWO DIMENSIONAL OPTICAL DETECTOR WITH MULTIPLE SHIFT REGISTERS

摘要

Methods and systems for enhancing the throughput of a metrology system generating measurement signals based on at least two different optical properties of the illumination light are presented. A detector having a two dimensional photosensitive area is subdivided into multiple photosensitive stripes by multiple, independent linear arrays of shift register elements located within the photosensitive area. Charge transfer from pixels within each stripe is directed to a distinct linear array of shift register elements. Each photosensitive stripe is able to resolve an optical property dispersed across the length of each stripe with relatively high resolution. In addition, the detector is able to resolve another optical property dispersed across several photosensitive stripes in a direction orthogonal to each linear array of shift registers at a relatively low resolution.

主权项

1. An optical detector comprising:
a photosensitive area having a first dimension in a first direction and a second dimension in a second direction, the first direction orthogonal to the second direction, the first dimension greater than the second dimension, the photosensitive area including:
a first array of photodetectors arranged in a first portion of the photosensitive area along the first direction;a second array of photodetectors arranged in a second portion of the photosensitive area along the first direction; anda first linear array of shift register elements disposed along the first direction between the first and the second array of photosensitive elements, wherein a charge accumulated on the first array of photodetectors is transferred to the first linear array of shift register elements, and wherein a charge accumulated on the second array of photodetectors is transferred to the a second linear array of photodetector elements.