Chromatic confocal area sensor
AssigneeKLA-Tencor Corporation
InventorsChristophe Wouters, Kristof Joris, Johan De Greeve
Life of this patent
Estimating the term…
Abstract
3D measurements of features on a workpiece, such as ball height, co-planarity, component thickness, or warpage, are determined. The system includes a broadband light source, a microlens array, a tunable color filter, a lens system, and a detector. The microlens array can focus a light beam to points in a focal plane of the microlens array. The tunable color filter can narrow the light beam to a band at a central wavelength. The lens system can provide longitudinal chromatic aberration whereby different wavelengths are imaged at different distances from the lens system.
Claims18
A system comprising:
- a broadband light source that generates a light beam;
- a stage configured to hold a workpiece;
- a microlens array positioned in a path of the light beam, wherein the microlens array focuses the light beam to a plurality of points in a focal plane of the microlens array, and wherein the microlens array is configured as a spatial filter for the light beam that is reflected from the workpiece on the stage thereby only passing the light beam that is in focus at the workpiece on the stage;
- a tunable color filter positioned in the path of the light beam, wherein the tunable color filter is configured to narrow the light beam to a band at a central wavelength;
- a lens system positioned to image the plurality of points onto the workpiece using the light beam, wherein the lens system is configured to provide longitudinal chromatic aberration whereby different wavelengths are imaged at different distances from the lens system;
- and
- a detector positioned to receive the light beam from the workpiece on the stage, wherein the light beam reflected from the workpiece on the stage is directed through the microlens array before being received by the detector.
A method comprising:
- generating a light beam using a broadband light source;
- focusing, using a microlens array, the light beam into a plurality of points in a focal plane of the microlens array, wherein the microlens array is configured as a spatial filter;
- narrowing the light beam to a band at a central wavelength using a tunable color filter;
- imaging a plurality of points onto a workpiece using a lens system, wherein the lens system is configured to provide longitudinal chromatic aberration whereby different wavelengths are imaged at different distances from the lens system;
- passing the light beam reflected from the workpiece that is in focus at the workpiece using the microlens array;
- and
- receiving the light beam reflected from the workpiece at a detector.
Dependencies are inferred from the claim text.