Alignment and exposure apparatus
AssigneeCanon Kabushiki Kaisha
InventorsNoriyuki Mitome, Hideki Ina
Life of this patent
Estimating the term…
Abstract
An alignment and exposure apparatus for aligning an original such as a reticle and a workpiece such as a wafer and for photolithographically transferring a pattern of the original onto the workpiece. The alignment of the original and the workpiece is achieved by detecting diffractively scattered light from alignment marks of the original and the workpiece. For this alignment, plural and different wavelengths are used. One of the wavelengths which is close to an exposure wavelength is used to detect both the original and the workpiece. Another wavelength is used to detect only the workpiece. By this, high-accuracy alignment of the original and the workpiece is ensured.
Claims6
A projection exposure apparatus for projecting a pattern of an original having an alignment mark on a workpiece having an alignment mark, said exposure apparatus comprising:
- a first stage for supporting the original;
- a second stage for supporting the workpiece;
- an illumination system for illuminating the original with light having a predetermined wavelength;
- a projection lens system for projecting the pattern of the original illuminated by said illumination system on the workpiece;
- an alignment mark illuminating arrangement for providing a first light of a first wavelength, substantially the same as the predetermined wavelength, and a second light of a second wavelength different from the first wavelength, said illuminating arrangement being adapted to direct the first and second lights toward the original and the workpiece so that the first light is focused on the original while the second light is not focused on the original and such that both the first and second lights are focused on the workpiece through said projection lens system, and said illuminating arrangement including means for scanning the first and second lights so that the alignment marks of the original and the workpiece are scanned with the first and second lights;
- converting means for receiving diffracted light components from the alignment marks of the original and the workpiece, scanned with the first and second lights, and for photoelectrically converting the received light components into electric signals;
- and
- adjusting means for adjusting a positional relationship between the original and the workpiece on the basis of the signals from said converting means.
Dependencies are inferred from the claim text.