System and method for double sided optical inspection of thin film disks or wafers
AssigneeKLA-Tencor Technologies Corporation
InventorSteven W. Meeks
Life of this patent
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Abstract
A double-sided optical inspection system is presented which may detect and classify particles, pits and scratches on thin film disks or wafers in a single scan of the surface. In one embodiment, the invention uses a pair of orthogonally oriented laser beams, one in the radial and one in the circumferential direction on both surfaces of the wafer or thin film disk. The scattered light from radial and circumferential beams is separated via their polarization or by the use of a dichroic mirror together with two different laser wavelengths.
Claims40
A method for measuring a defect on a surface of an object, comprising:
- directing a first light beam in a first plane of incidence toward a first position on the object;
- directing a second light beam in a second plane of incidence toward a second position on the object, wherein the angle between the first plane of incidence and the second plane of incidence is not equal to zero;
- separating a scattered light intensity into a first scattered light beam and a second scattered light beam, wherein the scattered light intensity comprises light intensity scattered from the first position and the second position;
- detecting the first scattered light beam;
- and
- detecting the second scattered light beam;
A method for measuring defects on a first surface and a second surface of a double-sided object comprising:
- directing a first light beam in a first plane of incidence toward a first position on the first surface of the object;
- directing a second light beam in a second plane of incidence toward a second position on the first surface of the object, wherein the angle between the first plane of incidence and the second plane of incidence is not equal to zero;
- directing a third light beam in a third plane of incidence toward a third position on the second surface of the object;
- directing a fourth light beam in a fourth plane of incidence toward a fourth position on the second surface of the object, wherein the angle between the third plane of incidence and the fourth plane of incidence is not equal to zero;
- separating a first surface scattered light intensity into a first scattered light beam and a second scattered light beam, wherein the first surface scattered light intensity comprises light intensity scattered from the first position and the second position;
- separating a second surface scattered light intensity into a third scattered light beam and a fourth scattered light beam, wherein the second surface scattered light intensity comprises light intensity scattered from the third position and the fourth position;
- detecting the first scattered light beam;
- detecting the second scattered light beam;
- detecting the third scattered light beam;
- and
- detecting the fourth scattered light beam.
Dependencies are inferred from the claim text.