Optical method and apparatus for inspecting large area planar objects
First Claim
1. An optical inspection module for inspecting a substrate having first and second opposite planar surfaces, the module comprising:
- a substrate holding position;
a first measurement instrument comprising;
a first illumination path extending to the substrate holding position and having a grazing angle of incidence with respect to the first surface of the substrate when the substrate is held in the substrate holding position, wherein the first illumination path illuminates substantially the entire first surface;
a first optical element, which is oriented to collect non-specularly reflected light that is scattered from the first illumination path by the first surface, the first optical element having a focal plane; and
a first photodetector having a plurality of pixels which are positioned within the focal plane of the first optical element, wherein each pixel corresponds to an area on the first surface and the plurality of pixels together form a field of view that covers substantially the entire first surface; and
a second measurement instrument comprising a sensor oriented for sensing a physical characteristic of the second surface when the substrate is held in the substrate holding position and the first surface is being illuminated.
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Accused Products
Abstract
An optical inspection module is provided for detecting defects on a substrate having first and second opposite planar surfaces. The module includes a substrate holding position and first and second measurement instruments. The first instrument includes a first illumination path extending to the substrate holding position and having a grazing angle of incidence with the first surface, which illuminates substantially the entire first surface. A first optical element is oriented to collect non-specularly reflected light scattered by the first surface. A first photodetector has a plurality of pixels positioned within a focal plane of the first lens, which together form a field of view that covers substantially the entire first surface. The second instrument includes a sensor oriented for sensing a physical characteristic of the second surface when the substrate is held in the substrate holding position and the first surface is being illuminated.
174 Citations
15 Claims
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1. An optical inspection module for inspecting a substrate having first and second opposite planar surfaces, the module comprising:
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a substrate holding position;
a first measurement instrument comprising;
a first illumination path extending to the substrate holding position and having a grazing angle of incidence with respect to the first surface of the substrate when the substrate is held in the substrate holding position, wherein the first illumination path illuminates substantially the entire first surface;
a first optical element, which is oriented to collect non-specularly reflected light that is scattered from the first illumination path by the first surface, the first optical element having a focal plane; and
a first photodetector having a plurality of pixels which are positioned within the focal plane of the first optical element, wherein each pixel corresponds to an area on the first surface and the plurality of pixels together form a field of view that covers substantially the entire first surface; and
a second measurement instrument comprising a sensor oriented for sensing a physical characteristic of the second surface when the substrate is held in the substrate holding position and the first surface is being illuminated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An optical inspection module for inspecting a substrate having first and second opposite planar surfaces, the module comprising:
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a substrate holding position;
a first illumination path extending to the substrate holding position and having a grazing angle of incidence with respect to the first surface of the substrate when the substrate is held in the substrate holding position, wherein the first illumination path illuminates substantially the entire first surface;
a first optical element, which is oriented to collect non-specularly reflected light that is scattered from the first illumination path by the first surface, the first optical element having a focal plane;
a first photodetector having a plurality of pixels which are positioned within the focal plane of the first optical element, wherein each pixel corresponds to an area on the first surface and the plurality of pixels together form a field of view that covers substantially the entire first surface;
a second illumination path extending to the substrate holding position and having a grazing angle of incidence with respect to the second surface of the substrate when the substrate is held in the substrate holding position, wherein the second illumination path illuminates substantially the entire second surface;
a second optical element, which is oriented to collect non-specularly reflected light that is scattered from the second illumination path by the second surface, the second optical element having a focal plane; and
a second photodetector having a plurality of pixels which are positioned within the focal plane of the second optical element, wherein each pixel corresponds to an area on the second surface and the plurality of pixels together form a field of view that covers substantially the entire second surface. - View Dependent Claims (13, 14)
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15. An optical inspection module for inspecting a substrate having an active surface and an opposite, back surface, the module comprising:
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a substrate holding position;
a first measurement instrument comprising;
a first illumination path extending to the substrate holding position and having a grazing angle of incidence with the back surface when the substrate is held in the substrate holding position, wherein the first illumination path illuminates substantially the entire back surface;
a first optical element, which is oriented to collect non-specularly reflected light that is scattered from the first illumination path by the back surface, the first optical element having a focal plane; and
a first photodetector having a plurality of pixels which are positioned within the focal plane of the first optical element, wherein each pixel corresponds to an area on the back surface and the plurality of pixels together form a field of view that covers substantially the entire back surface; and
a second measurement instrument comprising;
a second illumination path extending to the substrate holding position and illuminating at least a portion of the active surface when the substrate is held in the substrate holding position;
a second optical element, which is oriented to collect light reflected from the second illumination path by defects on the active surface and has a focal plane; and
a second photodetector having at least one pixel, which is positioned within the focal plane of the second optical element, wherein the second measurement instrument has a defect sensitivity that is greater than that of the first measurement instrument and is capable of detecting smaller defects on the active surface than the first measurement instrument is capable of detecting on the back surface.
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Specification