RETICLE DEFECT INSPECTION APPARATUS AND RETICLE DEFECT INSPECTION METHOD
First Claim
1. A reticle defect inspection method in which an image sensor (11) is moved relative to a reticle (1), and an optical image obtained by amplifying an output of each pixel of the image sensor by a sensor amplifier (15) is compared with a reference image defined as a standard image relative to the optical image to perform a defect inspection of the reticle,the sensor amplifier (15) being capable of calibrating a gain and an offset of a signal amplitude every pixel, the reticle defect inspection method comprising, before the defect inspection:
- imaging some of patterns of the reticle (1) by the image senor (11), and storing bottom and peak values of an amount-of-light signal of each pixel amplified by the sensor amplifier (15);
setting a plurality of offsets in the sensor amplifier by setting each offset of a signal amplitude for each pixel of the sensor amplifier (15), based on stored bottom value of each pixel; and
setting a plurality of gains in the sensor amplifier by setting each gain of a signal amplitude for each pixel of the sensor amplifier (15), based on the offset of the signal amplitude of each pixel and on stored peak value of each pixel.
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Accused Products
Abstract
The present invention provides a reticle defect inspection method and a reticle defect inspection apparatus capable of calibrating the offset and gain of a sensor amplifier using a product reticle even though black and white regions each sufficiently wider than a TDI sensor imaging area do not exist in the product reticle. An output of each pixel of the TDI sensor is amplified by the sensor amplifier. A bottom value of the amplified amount-of-light signal of each pixel is stored by bottom value storing means of offset/gain calibrating means, and a peak value thereof is stored by peak value storing means. The offset of each pixel is calculated by offset calculating means based on the bottom value of each pixel. The gain of each pixel is calculated by gain calculating means based on the offset of each pixel and the peak value of each pixel. The calculated offset and gain of each pixel are stored in a register and thereby the offset and gain of the sensor amplifier are calibrated.
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Citations
20 Claims
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1. A reticle defect inspection method in which an image sensor (11) is moved relative to a reticle (1), and an optical image obtained by amplifying an output of each pixel of the image sensor by a sensor amplifier (15) is compared with a reference image defined as a standard image relative to the optical image to perform a defect inspection of the reticle,
the sensor amplifier (15) being capable of calibrating a gain and an offset of a signal amplitude every pixel, the reticle defect inspection method comprising, before the defect inspection: -
imaging some of patterns of the reticle (1) by the image senor (11), and storing bottom and peak values of an amount-of-light signal of each pixel amplified by the sensor amplifier (15); setting a plurality of offsets in the sensor amplifier by setting each offset of a signal amplitude for each pixel of the sensor amplifier (15), based on stored bottom value of each pixel; and setting a plurality of gains in the sensor amplifier by setting each gain of a signal amplitude for each pixel of the sensor amplifier (15), based on the offset of the signal amplitude of each pixel and on stored peak value of each pixel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A reticle defect inspection apparatus comprising:
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a light irradiating mechanism (6,7) for irradiating a reticle (1) formed with each pattern with light; driving means (4A,4B,4C,14) for driving a stage (2) which holds the reticle (1) thereon; an image sensor (11) for detecting an amount-of-light signal of light transmitted through or reflected from the reticle (1) at a plurality of pixels; a sensor amplifier (15) for amplifying an output of each pixel of the image sensor (11) every pixel and generating an optical image, the sensor amplifier being capable of calibrating a gain and an offset of a signal amplitude every pixel; reference image generating means (18) for generating a reference image defined as a standard image relative to the optical image; detecting means (19) for comparing the optical image with the reference image thereby to detect a defect of each pattern of the reticle (1); storing means (16a,16b), when the stage (2) is driven by the driving means (4A,4B,4C,14) before the inspection by the detecting means (19) to image some of the patterns by the image sensor (11), for storing bottom and peak values of an amount-of-light signal of each pixel amplified by the sensor amplifier (15); offset setting means (16c,16) for setting an offset of a signal amplitude for each pixel of the sensor amplifier (15), based on the bottom value of each pixel stored by the storing means (16a); and gain setting means (16d) for setting a gain of a signal amplitude for each pixel of the sensor amplifier (15), based on the offset of the signal amplitude for each pixel and the peak value of each pixel stored by the storing means (16b). - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification