Inspection systems performing two-dimensional imaging with line light spot
AssigneeApplied Materials, Inc.
InventorsSilviu Reinhron, Gilad Almogy
Life of this patent
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Abstract
A wafer inspection system is described. The wafer is illuminated by an elongated “linear” or “line spot.” The “line spot” is basically an elongated illumination on the wafer surface, such that it covers several pixels aligned to form a line. The linear spot is held stationary with respect to one direction, but the wafer is scanned under it in the other direction. Thus, a two dimensional area is covered and can be imaged. Imaging is preferably performed using a sensor array, such as a line CCD. In the preferred embodiment, two linear spots are used in conjunction with two line CCD's. When inspecting a patterned wafer, the linear spots are projected at complementing 45° angles to the “streets and avenues” axis of the wafer.
Claims14
Method for the illumination of a two dimensional area on a substrate, comprising:
- illuminating a line spot on the substrate;
- scanning the substrate in a single direction;
- collecting reflected light at a first angle with respect to a normal to said substrate;
- and
- collecting scattered light at a second angle with respect to said normal to said substrate;
- and
- illuminating the substrate with a second line spot oriented at 90° with respect to the line spot.
A system for two dimensional scanning of a substrate, comprising:
- a light source providing a light beam;
- a conversion system converting the light beam into a main line beam;
- a beam splitter splitting the main line beam into a first and a second line beams;
- a first optical system projecting the first line beam onto the substrate to illuminate the substrate with a first line spot;
- a second optical system projecting the second line beam onto the substrate to illuminate the substrate with a second line spot;
- a scanning system providing a relative displacement between the first and second line beams and the substrate;
- and,
- a first sensor array associated with the first line spot;
- and
- a second sensor array associated with the second line spot.
A system for two dimensional imaging of a substrate having two perpendicular axis defined thereon, comprising:
- a light source providing a light beam;
- a conversion system converting the light beam into a main line beam;
- a beam splitter splitting the main line beam into a first and a second line beams;
- a first optical system projecting the first line beam onto the substrate to illuminate the substrate with a first line spot positioned at 45° to the axis;
- a second optical system projecting the second line beam onto the substrate to illuminate the substrate with a second line spot, positioned at 90° to the first line spot;
- a scanning system providing a relative displacement between the first and second line beams and the substrate;
- and,
- a first sensor array associated with the first line spot;
- and
- a second sensor array associated with the second line spot.
Dependencies are inferred from the claim text.