Agilent Technologies, Inc.

Fairchild Semiconductor Corporation

Alan B Ray

Miao Zhu

William Clay Schluchter

Geraint Owen

John J Bockman

Eric Stephen Johnstone

Carol Courville

William R Trutna, Jr

Leonard S Cutler

David C Chu

Kerry D Bagwell

James B Prince

Greg C Felix

Douglas P Woolverton

Louis F Mueller

Kerry Bagw Ell

Paul E Riley

Paul Bayer

Gerry Owen

Jeffrey A Young

An interferometer and corresponding system are provided having several aspects. In a first aspect, there is provided an interferometer adapted to receive separate first and second beams fand ftherein, the interferometer comprising substantially equivalent and separate first and second optical pathways for the first and second beams fand f. In a second aspect, there is provided an interferometer adapted to receive as separate inputs therein first and second beams fand f, where such beams are not mixed or combined until just prior to being output by the interferometer. In a third aspect, an interferometer is provided having one or more beam blockers for intercepting extraneous or undesired light, and keeping such light from contaminating or interfering with separate beams fand f.

Monolithic displacement measuring interferometer with spatially separated but substantially equivalent optical pathways and optional dual beam outputs

A sensor head for use with a measurement grating is described. The sensor head comprises: a splitter grating configured to split a light beam into first and second measurement beams; a first retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating; and a second retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating. In one embodiment the second measurement beam is diffracted by the measurement grating to form first and second sub-beams and one of the first and second sub-beams comprises a zeroth order diffraction component and a first order diffraction component. In another embodiment, the first and second sub-beams each comprise a zeroth order diffraction component and a first order diffraction component.

Displacement measurement sensor head and system having measurement sub-beams comprising zeroth order and first order diffraction components

A displacement measurement apparatus includes a light source, a splitter grating, a measurement grating, and first a second detector arrays. The splitter grating splits a light beam into first and second measurement channels that each illuminates the measurement grating. The first and second measurement channels split into 0and 1order diffraction products at the measurement grating in a first pass and recombine at the measurement grating in a second pass before being measured at the first and second detector arrays.

Displacement measurement system

An apparatus and method for measuring displacement includes a light beam directed to an interferometer core that splits the light beam into first and second component beams. The first component beam is directed to a diffraction grating at approximately a Littrow angle. A diffraction is received by the interferometer core and is combined with the second component beam. The combination of the first and second component beams is measured to determine displacement of the diffraction grating.

Littrow interferometer

A multi-axis plane mirror interferometer uses shared measurement and reference beams that respectively reflect from measurement and reference reflectors before that shared beams are split into individual beams corresponding to the measurement axes of the interferometer. An N-axis interferometer thus requires only N+1 measurement beam paths, one for the shared measurement beam and N for individual measurement beams, to provide for each measurement axis the two reflections that cancel angular misalignment between the measurement and reference reflectors.

Compact multi-axis interferometer

A system and method for acquiring position information of a movable apparatus relevant to a specific axis is disclosed. In one embodiment, an interferometer generates first and second beams and various beam-steering members are located to define beam path segments for the two beams, but no beam path segment varies in length in unity with displacements of the movable apparatus along the specific axis. In another or the same embodiment, each beam path segment in which the first beam either impinges or has been reflected from the movable apparatus is symmetrical to a corresponding beam path segment of the second beam. The movable apparatus may be a wafer stage in which the 'specific axis' is the exposure axis of a projection lens, but with all optical members which cooperate with the stage being located beyond the ranges of the wafer stage in directions perpendicular to the lithographic exposure axis.

System and method of using a side-mounted interferometer to acquire position information

An interferometer returns parallel beams that are subject to walk-off caused by reflector misalignment for an additional pass through the interferometer optics and thereby eliminates beam walk-off. A return reflector can be a plane mirror that directs returning beams to retrace paths through the interferometer optics to combine and exit along the axis of the input beam. Separation optics can separate the combined beam from the input beam. Alternatively, a return reflector such as an isosceles prism or a trapezoidal prism reflects and offsets returning beams so that the combined beam is offset from the input beam. The return reflector more generally responds to a shift in incident beam position with a matching shift of the reflected beam in contrast to a retroreflector, which shifts a reflected beam in a direction opposite to the shift in the incident beam.

Interferometer using beam re-tracing to eliminate beam walk-off

A multi-axis interferometer uses a combined beam for a first pass through the interferometer optics. Measurement and reference components of the combined beam that exit the interferometer optics are subject to walk-off that measurement or reference reflector misalignment can cause. A return reflector and non-polarizing beam splitter system split the combined beam into separated input beams for the various axes of the interferometer and return the separated beams for respective second passes through the interferometer optics. Walk-off for the separated beams in the interferometer optics cancels the walk-off for the combined beam to eliminate beam walk-off in separated output beams. Sharing a combined beam for a first pass through the interferometer optics reduces the sizes required for the interferometer optics and reference and measurement mirrors. The multi-axis interferometer may have a single return reflector.

Compact beam re-tracing optics to eliminate beam walk-off in an interferometer

A method for planarizing an insulating layer overlying an irregular topographic substrate, e.g., a conductive layer, is planarized by use of a sacrificial planarization layer. The planarization layer is removed using an oxygen-containing plasma generated in a parallel electrode reactor operating at a low excitation frequency and high pressure. Once the interface between the planarization layer and the conductive layer is reached, a second plasma with a reduced oxygen content is employed to avoid overetching the planarization layer. It has been observed that oxidizing species liberated during the etching of the insulating layer, typically silicon dioxide, contribute to the oxidation and hence removal of the planarization layer. The process may be monitored by observing the spectral emissions from species generated or consumed during planarization or by changes in the optical interference pattern, allowing termination of the etch at the proper time to avoid over-etching and under-etching of the insulating layer.

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Palo Alto, CA, United States of America

Alan B Ray