초록 ▼

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

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.

대표청구항 ▼

What is claimed is: 1. 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

What is claimed is: 1. 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. The system of claim 1, wherein the one portion of the spot has an area on the wafer that is approximately equal to the entire area of the spot on the wafer. 3. The system of claim 1, wherein an area of the one portion of the spot is larger than an area of each of the different portions of the spot. 4. The system of claim 1, wherein none of the different portions within the spot overlap any other of the different portions within the spot. 5. The system of claim 1, wherein the different portions in combination extend across an area within the spot that is smaller than the entire area of the spot. 6. The system of claim 1, wherein the first detection subsystem comprises an ellipsoidal collector configured to collect the light scattered from the one portion of the spot on the wafer. 7. The system of claim 1, wherein the second detection subsystem is further configured to detect the light scattered from the different portions at one or more polar angles that are closer to the wafer than polar angles at which the first detection subsystem detects the scattered light. 8. The system of claim 1, wherein the second detection subsystem is further configured to preserve information about the different portion of the spot from which the separately detected light was scattered and to not preserve information about polar and azimuthal angles within the entire collection space of the second detection subsystem at which the light was scattered from the different portions of the spot. 9. The system of claim 1, wherein the second detection subsystem further comprises a collector configured to collect the light scattered from the different portions of the spot. 10. The system of claim 1, wherein the first detector comprises a multi-anode photomultiplier tube. 11. The system of claim 1, wherein the first detector comprises physically separated detection elements, and wherein the second detection subsystem further comprises a mask positioned in front of the first detector to increase optical separation between the physically separated detection elements. 12. The system of claim 1, wherein the second detection subsystem further comprises optical fibers configured to separately and simultaneously direct the light scattered from the different portions to different detection elements such that the different detection elements separately and simultaneously detect the light scattered from the different portions of the spot, and wherein the second detection subsystem further comprises micro-lenses positioned in front of the optical fibers and configured to eliminate dead spaces between adjacent optical fibers. 13. The system of claim 1, wherein the second detection subsystem is further configured such that the different output separately generated by the second detection subsystem is substantially unaffected by movement of the wafer in a direction substantially perpendicular to a surface of the wafer being inspected. 14. The system of claim 1, wherein the illumination subsystem is further configured to direct the light to the spot on the wafer at the oblique angle of incidence and a first azimuthal angle, wherein the second detection subsystem is further configured to separately and simultaneously detect the light scattered from the different portions of the spot at one or more azimuthal angles different than the first azimuthal angle, and wherein the first azimuthal angle and the one or more azimuthal angles are not opposite to each other. 15. The system of claim 1, further comprising a third detection subsystem configured to separately and simultaneously detect light scattered from the different portions of the spot on the wafer and to separately generate different output responsive to the scattered light separately detected by the third detection subsystem, wherein the second and third detection subsystems collect and detect the scattered light at different azimuthal angles. 16. The system of claim 1, further comprising a third detection subsystem configured to detect light scattered from the one portion of the spot on the wafer and to generate output responsive to the scattered light detected by the third detection subsystem, wherein the third detection subsystem comprises a refractive collector positioned such that an optical axis of the refractive collector is substantially perpendicular to a surface of the wafer being inspected. 17. The system of claim 1, further comprising a third detection subsystem configured to separately and simultaneously detect light scattered from the different portions of the spot on the wafer and to separately generate different output responsive to the scattered light separately detected by the third detection subsystem, wherein the third detection subsystem comprises a refractive collector positioned such that an optical axis of the refractive collector is substantially perpendicular to a surface of the wafer being inspected. 18. The system of claim 1, wherein the computer subsystem is further configured to perform a convolution on the different output separately generated by the second detection subsystem and to detect the defects on the wafer using results of the convolution. 19. The system of claim 1, further comprising a stage configured to rotate and translate the wafer while the light is directed to the spot on the wafer by the illumination subsystem such that the light directed to the spot is scanned across the wafer. 20. 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. 21. 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.