Method and device for mutually aligning a mask pattern formed in a mask and a substrate
AssigneeCarl-Zeiss-Stiftung
InventorBernhard Weigl
Life of this patent
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Abstract
In a method for mutually aligning a mask pattern formed in a mask 1 and a substrate 2, on which the mask pattern is to be imaged, by using setting marks 12a, 12b and 13a or 13b in the mask 1 and in the substrate 2, the alignment is performed with the aid of an imaging system and a light beam with polarized light 9. A phase shift for the first diffraction orders 20 is undertaken in the beam path 9a, 9b. Higher diffraction orders 21 and unwanted light are filtered out after the phase shift, and after the filtering out the light beams of the first diffraction orders 20 are detected, and the result is evaluated for the purpose of alignment.
Claims9
A method for mutually aligning a mask pattern formed in a mask and a substrate, on which the mask pattern is to be imaged, by using setting marks in the mask and in the substrate, the alignment being performed with the aid of an imaging system and a light beam with polarized light, wherein
- a) a phase shift for the first diffraction orders (20) is undertaken in the beam path (9a, 9b),
- b) higher diffraction orders (21) and unwanted light are filtered out after the phase shift, and
- c) after the filtering out the light beams of first diffraction orders (20) are detected, and the result is evaluated for alignment purposes.
Dependencies are inferred from the claim text.