Lithographic apparatus, level sensor, method of inspection, device manufacturing method, and device manufactured thereby
First Claim
Patent Images
1. A plurality of lithographic projection apparatus comprising:
- a radiation system configured to provide a projection beam of radiation;
a support structure configured to support a patterning structure, the patterning structure serving to pattern the projection beam according to a desired pattern;
a substrate table configured to hold a substrate; and
a projection system configured to project the patterned beam onto a target portion of the substrate,wherein each lithographic apparatus includes a level sensor comprising;
a first reflector positioned to direct light from a light source towards a wafer surface; and
a second reflector positioned to direct light reflected from the wafer surface to a detector,wherein the first reflectors of the level sensors of the plurality of lithographic apparatus are substantially identical to one another,wherein the second reflectors of the level sensors of the plurality of lithographic apparatus are substantially identical to one another,wherein the first and the second reflectors are configured to incur a minimal process dependent apparent surface depression.
1 Assignment
0 Petitions
Accused Products
Abstract
A level sensor for a lithographic projection apparatus according to one embodiment of the invention includes a light source, a first reflector, a second reflector and a detector. The first reflector is positioned to direct light from the light source towards a wafer surface, and the second reflector is positioned to direct light reflected from the wafer surface to the detector. The first and second reflectors are selected to incur a minimal process dependent apparent surface depression.
49 Citations
22 Claims
-
1. A plurality of lithographic projection apparatus comprising:
-
a radiation system configured to provide a projection beam of radiation; a support structure configured to support a patterning structure, the patterning structure serving to pattern the projection beam according to a desired pattern; a substrate table configured to hold a substrate; and a projection system configured to project the patterned beam onto a target portion of the substrate, wherein each lithographic apparatus includes a level sensor comprising; a first reflector positioned to direct light from a light source towards a wafer surface; and a second reflector positioned to direct light reflected from the wafer surface to a detector, wherein the first reflectors of the level sensors of the plurality of lithographic apparatus are substantially identical to one another, wherein the second reflectors of the level sensors of the plurality of lithographic apparatus are substantially identical to one another, wherein the first and the second reflectors are configured to incur a minimal process dependent apparent surface depression. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A lithographic apparatus comprising a level sensor, said level sensor comprising:
-
a first reflector configured to direct a beam from a light source toward a wafer surface; and a second reflector configured to direct the beam from the wafer surface to a detector, wherein a reflective surface of the first reflector has a coating, said coating having an optical thickness of 430 nanometers+/−
60 nanometers at a central wavelength of the beam,wherein a reflective surface of the second reflector has a coating, said coating having an optical thickness of 430 nanometers+/−
60 nanometers at a central wavelength of the beam,wherein the first and the second reflectors are configured to incur a minimal process dependent apparent surface depression. - View Dependent Claims (10, 11, 12, 13)
-
-
14. A lithographic apparatus comprising a level sensor configured to measure a height of a wafer surface, said level sensor comprising:
-
a first reflector configured to direct a beam from a light source toward the wafer surface; and a second reflector configured to direct the beam from the wafer surface to a detector, wherein a reflective surface of at least one of the first and second reflectors comprises aluminum having a coating of native oxide, and wherein the first and the second reflectors are configured to incur a minimal process dependent apparent surface depression. - View Dependent Claims (15, 16, 17, 18)
-
-
19. A lithographic apparatus comprising a level sensor, said level sensor comprising:
-
a first reflector system configured to direct a beam from a light source toward a wafer surface; and a second reflector system configured to direct the beam from the wafer surface to a detector, wherein the first reflector system includes a first surface configured to direct the beam toward the wafer surface and a second surface configured to direct the beam toward the first surface, wherein the second reflector system includes a first surface configured to direct the beam to the detector and a second surface configured to direct the beam toward the first surface, and wherein the first and the second reflectors systems are configured to incur a minimal process dependent apparent surface depression. - View Dependent Claims (20, 21, 22)
-
Specification