Edge registration for interferometry
AssigneeCorning Incorporated
InventorsTHOMAS JAMES DUNN, Paul Francis Michaloski
Life of this patent
Estimating the term…
Abstract
A metrology apparatus has an illumination source that directs collimated light to a reference surface and to an optical component having a test surface that is in parallel with the reference surface. A first imaging lens defines a Fourier transform plane for light reflected from the reference surface and the test surface. A spatial filtering element is actuable to a blocking position that blocks specular light at the transform plane. A second imaging lens forms, at an image plane, an image of the test surface. A sensor array generates image data from received light at the image plane.
Claims15
A metrology apparatus comprising:
- a) an illumination source that directs collimated light to a reference surface and to an optical component having a test surface that is in parallel with the reference surface;
- b) a first imaging lens that defines a Fourier transform plane for light reflected from both the reference surface and the test surface;
- c) a spatial filtering element that is actuable to a blocking position that blocks specular light at the transform plane;
- d) a second imaging lens that forms, at an image plane, an image of the test surface;
- and
- e) a sensor array disposed to generate image data from received light at the image plane.
A metrology apparatus comprising:
- a) an interferometer having a test surface and a reference surface;
- b) a first imaging lens that defines a Fourier transform plane for light reflected from the test and reference surfaces;
- c) a spatial filtering element that is actuable to a blocking position that blocks specular light from the test and reference surfaces at the Fourier transform plane and allows passage of scattered or diffracted light from the test surface;
- d) a second imaging lens that is disposed to form, at an image plane, an image of the test surface, from the light at the transform plane;
- e) a sensor array disposed to generate image data from received light at the image plane;
- and
- f) a display in signal communication with the sensor array for rendering the generated image data.
A method for substrate registration in an interferometer, the method comprising:
- a) directing a collimated light to a reference surface and to an optical component having a test surface disposed in parallel with the reference surface;
- b) forming a Fourier transform plane with light reflected from the reference surface and the test surface;
- c) actuating a spatial filtering element to a blocking position that blocks at least a portion of the reflected light at the transform plane;
- d) forming a dark field image of the test surface at an image plane, from the light at the transform plane;
- and
- e) acquiring image data from a sensor array that is disposed at the image plane.
Dependencies are inferred from the claim text.