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AssigneeMapper Lithography IP B.V.
InventorsGuido De Boer, Niels Vergeer
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The invention relates to a substrate for use in a lithography system, said substrate being provided with an at least partially reflective position mark comprising an array of structures, the array extending along a longitudinal direction of the mark, characterized in that said structures are arranged for varying a reflection coefficient of the mark along the longitudinal direction, wherein said reflection coefficient is determined for a predetermined wavelength. In an embodiment a specular reflection coefficient varies along the substrate, wherein high order diffractions are substantially absorbed by the substrate. A position of a beam on a substrate can thus be determined based on the intensity of its reflection in the substrate. The invention further relates to a positioning device and lithography system for cooperation with the substrate, and a method of manufacture of the substrate.
Substrate for use in a lithography system, said substrate being provided with an at least partially reflective position mark comprising an array of structures, the array extending along a longitudinal direction of the mark, wherein said structures are arranged for varying a reflection coefficient of the mark along the longitudinal direction, wherein said reflection coefficient is determined for a predetermined wavelength, characterized in that a pitch between a first structure of the array and a second structure of the array neighboring said first structure is different from a pitch between said second structure and a third structure of the array neighboring said second structure, and wherein the pitch between neighboring structures along the longitudinal direction follows a sinusoid function of the position of said structures along the longitudinal direction.
Substrate according to any one of the preceding claims, wherein said structures each have a width along the longitudinal direction, said width being less than said predetermined wavelength, and wherein a distance between neighboring structures along the longitudinal direction is less than said predetermined wavelength.
Substrate according to any one of the preceding claims, wherein said substrate comprises a wafer.
Substrate according to any one of the preceding claims, wherein the structures are aligned on points which are equidistantly spaced along the longitudinal direction.
Substrate according to any one of the preceding claims, adapted for cooperation with a positioning system which is adapted for emitting a light beam onto the substrate for generating a beam spot on said substrate, wherein the light beam has a wavelength equal to the predetermined wavelength, wherein a maximum distance between neighboring structures along the longitudinal direction is at most equal to the diameter of the beam spot.
Substrate according to any one of the preceding claims, wherein said structures form a periodic pattern of structures repeating along said longitudinal direction, and wherein the period of said pattern is larger than said diameter of the beam spot, preferably at least twice as large.
Substrate according to any one of the preceding claims, wherein said substrate is formed as an integrated unit from a single material.
Substrate according to any one of the preceding claims, wherein a maximum reflection coefficient of an area of the position mark for said wavelength is substantially equal to 1.
Method for manufacturing an alignment and/or positioning mark on a substantially reflective substrate to be illuminated by a beam, comprising a step of:
Dependencies are inferred from the claim text.