Apparatus for optical inspection of a working surface having a dynamic reflective spatial attenuator
First Claim
1. An optical surface inspection apparatus for determining the presence of unknown surface conditions on a target surface, comprising:
- illumination means for generating an incidence light beam;
scanning means for scanning the light beam across the target surface, whereby the target surface scatters light in the presence of the light beam;
light collection means for collecting scattered light, said light collection means comprises;
(a) detector means for detecting light;
(b) a dynamic reflective spatial attenuator receiving scattered light from the target surface;
(c) control means for controlling the dynamic reflective spatial attenuator to obtain an attenuation pattern that selectively diverts light to the detector means;
discriminating means for determining the presence of unknown surface conditions based on the light detected by the detector means.
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Accused Products
Abstract
A dynamic reflective spatial attenuator for use in an optical inspection apparatus. The attenuator takes the form of a two-dimensional micro-mechanical reflective array that, in the first operative position of a mirror element, reflects the desired scattered light toward a detector and, in the second operative position of a mirror element, reflects undesired scattered light into a light dump. The mirror array'"'"'s fast response and flexibility allows for changes during mid-scan to increase the defect'"'"'s or contaminant'"'"'s signal relative to the substrate surface'"'"'s signal.
36 Citations
25 Claims
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1. An optical surface inspection apparatus for determining the presence of unknown surface conditions on a target surface, comprising:
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illumination means for generating an incidence light beam;
scanning means for scanning the light beam across the target surface, whereby the target surface scatters light in the presence of the light beam;
light collection means for collecting scattered light, said light collection means comprises;
(a) detector means for detecting light;
(b) a dynamic reflective spatial attenuator receiving scattered light from the target surface;
(c) control means for controlling the dynamic reflective spatial attenuator to obtain an attenuation pattern that selectively diverts light to the detector means;
discriminating means for determining the presence of unknown surface conditions based on the light detected by the detector means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A process of inspecting a specimen to determine the presence of unknown surface conditions on a target surface, comprising the steps:
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scanning an incidence light beam across the target surface, whereby the target surface scatters light in the presence of the light beam;
collecting scattered light by applying a dynamic reflective spatial attenuator to obtain an attenuation pattern that selectively diverts light to a detector;
determining the presence of unknown surface conditions based on the light detected by the detector means. - View Dependent Claims (22, 23, 24, 25)
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Specification