| 摘要 |
Methods of determining asymmetric properties of structures are described. A method includes measuring, for a grating structure, a first signal and a second, different, signal obtained by optical scatterometry. A difference between the first signal and the second signal is then determined. An asymmetric structural parameter of the grating structure is determined based on a calculation using the first signal, the second signal, and the difference. |
| 主权项 |
1. A method of determining and applying an asymmetric property of a structure, the method comprising:
measuring for a grating structure, a first signal and a second, different, signal obtained by optical scatterometry of the grating structure, the measurement of the first signal and second signal being performed by an optical metrology tool of an optical metrology system; calculating with a processor of the optical metrology system:
a differential signal, the differential signal being a mathematical difference between the first signal and the second signal calculated by subtracting one of the first signal and the second signal from the other of the first signal and the second signal, anda value of an asymmetric structural parameter of the grating structure based on a calculation using the first signal, the second signal, and the calculated differential signal; and altering one or more parameters or settings for fabrication based at least in part on the calculated asymmetric structural parameter of the grating structure; wherein the first signal and the second signal are measured according to one of the following:
the first signal and the second signal are measured at first and second azimuth angles, respectively, of the grating structure,the first signal and the second signal are measured for first and second angles of incidence, respectively, of the grating structure,the first signal and the second signal are measured at first and second polarizer/analyzer angles, respectively, of the grating structure, orthe first signal and the second signal are measured for first and second measurement targets, respectively, of the grating structure. |
