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US 7,623,229 B1Granted
Systems and methods for inspecting wafers
AssigneeKLA-Tencor Corporation
InventorsMehdi Vaez-Iravani, Stephen Biellak
Life of this patent
Estimating the term…
Abstract
Systems and methods for inspecting wafers are provided. One system includes a detection subsystem configured to separately and simultaneously detect light scattered from different portions of a single spot obliquely, or normally, illuminated on a wafer and to separately generate output responsive to the separately detected light that can be used to detect defects on the wafer. The system can, therefore, effectively perform a multi-spot type of inspection of the wafer using only a single obliquely or normally illuminated spot on the wafer.
Claims21
A system configured to inspect a wafer, comprising:
- an illumination subsystem configured to direct light to a spot on the wafer at an oblique angle of incidence;
- a first detection subsystem configured to detect light scattered from one portion of the spot on the wafer and to generate output responsive to the detected light;
- a second detection subsystem configured to separately and simultaneously detect light scattered from different portions of the spot on the wafer and to separately generate different output responsive to the separately detected light, wherein the entire collection space of the second detection subsystem spans only a portion of azimuthal angles at which the first detection subsystem detects the scattered light, wherein the second detection subsystem comprises a first detector configured to separately and simultaneously detect the light scattered from the different portions of the spot and a second detector configured to separately and simultaneously detect the light scattered from the different portions of the spot, and wherein the first and second detectors are positioned such that there is a half pixel shift between the first and second detectors;
- and
- a computer subsystem configured to detect defects on the wafer using the output generated by the first detection subsystem and the different output separately generated by the second detection subsystem.
2 more elements
A method for inspecting a wafer, comprising:
- directing light to a spot on the wafer at an oblique angle of incidence;
- detecting light scattered from one portion of the spot on the wafer and generating first output responsive to the detected light scattered from the one portion;
- separately and simultaneously detecting light scattered from different portions of the spot on the wafer and separately generating different output responsive to the separately detected light using a detection subsystem, wherein the light scattered from the different portions is detected at only a portion of the azimuthal angles at which the light scattered from the one portion is detected, wherein the detection subsystem comprises a first detector configured to separately and simultaneously detect the light scattered from the different portions of the spot and a second detector configured to separately and simultaneously detect the light scattered from the different portions of the spot, and wherein the first and second detectors are positioned such that there is a half pixel shift between the first and second detectors;
- and
- detecting defects on the wafer using the first output and the separately generated different output.
2 more elements
A system configured to inspect a wafer, comprising:
- an illumination subsystem configured to direct light to a spot on the wafer at a substantially normal angle of incidence;
- a first detection subsystem configured to detect light scattered from one portion of the spot on the wafer and to generate output responsive to the detected light;
- a second detection subsystem configured to separately and simultaneously detect light scattered from different portions of the spot on the wafer and to separately generate different output responsive to the separately detected light, wherein the entire collection space of the second detection subsystem spans only a portion of azimuthal angles at which the first detection subsystem detects the scattered light, wherein the second detection subsystem comprises a first detector configured to separately and simultaneously detect the light scattered from the different portions of the spot and a second detector configured to separately and simultaneously detect the light scattered from the different portions of the spot, and wherein the first and second detectors are positioned such that there is a half pixel shift between the first and second detectors;
- and
- a computer subsystem configured to detect defects on the wafer using the output generated by the first detection subsystem and the different output separately generated by the second detection subsystem.
2 more elements
Dependencies are inferred from the claim text.