US5568256A — Method and apparatus utilizing an optical stage f…

Claim 1

Independent Claim 145 words

Apparatus for topographic analysis of a surface comprising at least one light source for radiating divergent light, a first light-distributing surface of a first diffraction grating for receiving light from the at least one light source and for reflecting a first bundle of light under normal optical conditions and a second bundle of light formed by diffraction of the first order, a first optical stage for projecting the first and second bundles from the first light-distributing surface in an optically conjugated form onto an object surface to be analyzed of a sample, light representing the object surface being sharply projected via the first optical stage onto a second light-distributing surface of a second diffraction grating, and a detector for receiving diffracted bundles of light from the second light-distributing surface projected by a second optical stage for detecting radiation enabling topographic analysis of the object surface.

Claim 2

Dependent Claim 145 words

Apparatus for topographic analysis of a surface comprising at least one light source for radiating divergent light, a first light-distributing surface of a first diffraction grating for receiving light from the at least one light source and for reflecting a first bundle of light under normal optical conditions and a second bundle of light formed by diffraction of the first order, a first optical stage for projecting the first and second bundles from the first light-distributing surface in an optically conjugated form onto an object surface to be analyzed of a sample, light representing the object surface being sharply projected via the first optical stage onto a second light-distributing surface of a second diffraction grating, and a detector for receiving diffracted bundles of light from the second light-distributing surface projected by a second optical stage for detecting radiation enabling topographic analysis of the object surface.

Claim 3

Dependent Claim 29 words

Apparatus according to claim 1, wherein the at least one light source is a light source module having a rotating focusing screen on which an extended spot is illuminated.

Claim 4

Dependent Claim 43 words

Apparatus according to claim 1, wherein at least one of the first and second diffraction gratings is at least one of a multiline grating, reflecting diffraction grating and holographic reflecting grating, and is located on one of a straight and a curved surface.

Claim 5

Dependent Claim 43 words

Apparatus according to claim 1, wherein at least one of the first and second diffraction gratings has a grating period selected so that an obliquely incident light beam in the first order of diffraction is radiated substantially orthogonally relative to a grating surface.

Claim 6

Dependent Claim 35 words

Apparatus according to claim 1, wherein at least one of the first and second diffraction gratings is a multi-line reflecting diffraction grating having a grating structure located on a surface matched with the object surface.

Claim 7

Dependent Claim 21 words

Apparatus according to claim 5, wherein the object surface is convex and the grating structure is disposed on a concave surface.

Claim 8

Dependent Claim 23 words

Apparatus according to claim 1, wherein at least one of the first and second light-distributing surfaces have grating structures with different grating periods.

Claim 9

Dependent Claim 30 words

Apparatus according to claim 7, wherein on each line of the grating structures having different grating periods include a small grating period and fine gratings have a higher grating period.

Claim 10

Dependent Claim 21 words

Apparatus according to claim 8, wherein the small grating period include 10 lines/mm and the higher grating period include 1,000 lines/mm.

Claim 11

Dependent Claim 30 words

Apparatus according to claim 1, wherein at least one of the first and second light-distributing surfaces is connected to a computer-controlled microtranslator for enabling application of a phase shift technique.

Claim 12

Dependent Claim 47 words

Apparatus according to claim 1, further comprising a reflector associated with the object surface and arranged in a substantially orthogonal relationship thereto so that one of a compensating plane through the object surface and a combination of the reflector and the object surface form a roof edge.

Claim 13

Dependent Claim 17 words

Apparatus according to claim 1, wherein the first optical stage is configured as a 4 f-type system.

Claim 14

Dependent Claim 48 words

Apparatus according to claim 1, wherein the second optical stage is disposed at a same angle as the first optical stage so as to create an arrangement which is symmetrical relative to the object surface in terms of an axial provision of the first and second optical stages.

Claim 15

Dependent Claim 33 words

Apparatus according to claim 1, wherein the at least one light source is interchangeable in position with a position of the detector so as to enable coverage of surface areas which are shaded.

Claim 16

Dependent Claim 81 words

Apparatus according to claim 1, wherein the first light-distributing surface is disposed obliquely relative to an optical axis of the first optical stage, and the object surface is disposed equally obliquely relative to the optical axis of the first optical stage so that light radiated from the first light source onto the first light-distributing surface arrives obliquely on the object surface to be analyzed via the first optical stage, and the first light-distributing surface and the object surface are optically conjugated.

Claim 17

Dependent Claim 149 words

Apparatus for analyzing a topography of a surface by strip projection comprising at least one light source for radiating light, at least one light-distributing surface for receiving light irradiated from the at least one light source, at least one optical stage, an object surface to be analyzed of a sample, and a detector for detecting radiation of the object surface to be analyzed, the at least one light-distributing surface being disposed obliquely relative to an optical axis of the at least one optical stage, and the object surface being disposed equally obliquely relative to the optical axis of the at least one optical stage so that light radiated from the at least one light source onto the at least one light-distributing surface arrives obliquely on the object surface via the at least one optical stage, and the at least one light-distributing surface and the object surface are optically conjugate.

Claim 18

Dependent Claim 149 words

Apparatus for analyzing a topography of a surface by strip projection comprising at least one light source for radiating light, at least one light-distributing surface for receiving light irradiated from the at least one light source, at least one optical stage, an object surface to be analyzed of a sample, and a detector for detecting radiation of the object surface to be analyzed, the at least one light-distributing surface being disposed obliquely relative to an optical axis of the at least one optical stage, and the object surface being disposed equally obliquely relative to the optical axis of the at least one optical stage so that light radiated from the at least one light source onto the at least one light-distributing surface arrives obliquely on the object surface via the at least one optical stage, and the at least one light-distributing surface and the object surface are optically conjugate.

Claim 19

Dependent Claim 23 words

Apparatus according to claim 16, wherein the object surface to be analyzed is illuminated by an oblique light beam at a wide angle.

Claim 20

Dependent Claim 26 words

Apparatus according to claim 16, wherein an image of the object surface in an area of the detector presents a geometric similarity with the object surface.

Claim 21

Dependent Claim 28 words

Apparatus according to claim 16, further comprising means for one of manually entering and iteratively and automatically determining an optimum sensitivity in the measurement of the object surface.

Claim 22

Dependent Claim 108 words

Apparatus according to claim 16, wherein the at least one optical stage includes a first optical stage of a 4 f-type system having a reflecting diffraction grating providing the at least one light-distributing surface which includes a first light-distributing surface and a second light-distributing surface, wherein a beat created between the reflecting diffraction grating and an image of the reflecting diffraction grating as the first light-distributing surface is projected onto the object surface of the sample and reflected back to the reflecting diffraction grating as the second light-distributing surface, and a beat image is projected onto a detector by a second optical stage for enabling analysis of shape.

Claim 23

Dependent Claim 126 words

A dual beam interferometer comprising a light source, a beam splitter surface at which a reference beam and object beams of an object beam bundle are generated, an object surface, at least one optical path-folding stage and at least one optical stage for projecting a course of the object and reference beams, at least one interference means having an interference pattern recordable via a further optical stage by a CCD camera connected to a computer, the at least one optical path-folding stage being provided with a computer-controlled adjusting element so that an optical path difference in the course of the object and reference beams, following the object surface between the reference beam and the object beams of the object beam bundle, is set approximately to zero.

Claim 24

Dependent Claim 126 words

A dual beam interferometer comprising a light source, a beam splitter surface at which a reference beam and object beams of an object beam bundle are generated, an object surface, at least one optical path-folding stage and at least one optical stage for projecting a course of the object and reference beams, at least one interference means having an interference pattern recordable via a further optical stage by a CCD camera connected to a computer, the at least one optical path-folding stage being provided with a computer-controlled adjusting element so that an optical path difference in the course of the object and reference beams, following the object surface between the reference beam and the object beams of the object beam bundle, is set approximately to zero.

Claim 25

Dependent Claim 49 words

A dual beam interferometer according claim 21, wherein the at least one optical stage is provided in the course of the reference beam and the object beams of the object beam bundle following the object surface and having an optical axis extending substantially in parallel to a beam axis.

Claim 26

Dependent Claim 23 words

A dual beam interferometer according claim 21, wherein the interference means include a light-distributing surface producing one of a light-diffusing and light-diffracting effect.

Claim 27

Dependent Claim 17 words

A dual beam interferometer according to claim 23, wherein the light-distributing surface is a holographic reflecting grating.

Claim 28

Dependent Claim 23 words

A dual beam interferometer according claim 20, wherein the optical path-folding stage is an optical reflecting system having a highly planar reflecting surface.

Claim 29

Dependent Claim 96 words

Apparatus for analyzing a shape of a surface comprising at least one light source for providing a light beam, a beam splitter system for splitting the light beam at least once to create two sub-beams and for generating a lateral shear in one of the two sub-beams relative to the other of the two sub-beams, and means for focusing the two sub-beams onto a sample so as to generate two sub-beams by reflection, and a beam recombination system for recombining the sub-beams and for at least one of reducing or eliminating lateral shear between the sub-beams.

Claim 30

Dependent Claim 96 words

Apparatus for analyzing a shape of a surface comprising at least one light source for providing a light beam, a beam splitter system for splitting the light beam at least once to create two sub-beams and for generating a lateral shear in one of the two sub-beams relative to the other of the two sub-beams, and means for focusing the two sub-beams onto a sample so as to generate two sub-beams by reflection, and a beam recombination system for recombining the sub-beams and for at least one of reducing or eliminating lateral shear between the sub-beams.

Claim 31

Dependent Claim 45 words

Apparatus according to claim 26, wherein the beam splitter system for generating lateral shear includes a Michelson's interferometer having at least two retro-reflectors, one polarization-dependent splitting layer, and one nonpolarizing layer, wherein the sub-beams are focused by projection so as to interfere with each other.

Claim 32

Independent Claim 103 words

A method of analyzing the shape of a surface, comprising the steps of splitting a light beam bundle at least once so as to create two sub-beams, one of the two sub-beams having a lateral shear relative to the other of the two sub-beams and the two sub-beams being focused at least once for arrival at a sample in the form of sub-beams so as to generate two sub-beams by reflection, recombining the sub-beams so as to at least one of reduce or eliminate the lateral shear between the sub-beams, and focusing the sub-beams by projection so as to interfere with each other.

Claim 33

Independent Claim 103 words

A method of analyzing the shape of a surface, comprising the steps of splitting a light beam bundle at least once so as to create two sub-beams, one of the two sub-beams having a lateral shear relative to the other of the two sub-beams and the two sub-beams being focused at least once for arrival at a sample in the form of sub-beams so as to generate two sub-beams by reflection, recombining the sub-beams so as to at least one of reduce or eliminate the lateral shear between the sub-beams, and focusing the sub-beams by projection so as to interfere with each other.

Claim 34

Dependent Claim 25 words

A method according to claim 28, further comprising the step of evaluating by electronic image processing techniques at least one order of interference which occurs.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-10-22	2000-04-22	2000-10-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-10-22	2004-04-22	2004-10-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-10-22	2008-04-22	2008-10-22	$7700.00	Window Closed / Lapsed

Method and apparatus utilizing an optical stage for topographic surface analysis

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