Method and system for phase/amplitude error detection of alternating phase shifting masks in photolithography
US7171034B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2002 |
| Grant date | Jan 30, 2007 |
| Priority date | — |
| Expiry date | Mar 26, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/84
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for detecting phase and amplitude error of an alternating phase shifting mask is disclosed. In an exemplary embodiment, the method includes passing a collimated light beam through a pair of adjacent, phase shifted openings in the phase shifting mask. Then, the beam intensities of diffracted light passed through the pair of adjacent openings are recorded as a function of angular position. From the recorded beam intensities, an angle α is determined at which a first diffraction order and a second diffraction order occurs, wherein α represents a deviation from a pair of symmetrically distributed diffraction orders. In addition, a minimum intensity and a maximum intensity are also determined from the recorded beam intensities, wherein the phase error is calculated from the determined value of α, and the amplitude error is calculated from the minimum intensity and said maximum intensity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.