초록 ▼

A photomask and reticle inspection method and apparatus wherein a selected surface area of an object is inspected and a first stream of data having signal values representing the image content of each pixel thereof is generated, a second stream of data having signal values representing the intended

A photomask and reticle inspection method and apparatus wherein a selected surface area of an object is inspected and a first stream of data having signal values representing the image content of each pixel thereof is generated, a second stream of data having signal values representing the intended image content of each pixel of the first stream of data is generated, corresponding portions of the first and second streams of data are stored in memory, any misalignment between the stored portions of the first and second streams of data is detected, the misaligned first and second portions of data are then aligned using shifts of an integral number of pixels and/or subpixel interpolation to correct the detected misalignment therebetween, corresponding subportions of the stored and aligned first and second portions of data are then compared to detect difference therebetween, and upon detecting a difference exceeding a predetermined threshold, the presence of a defect at a particular pixel location on the inspected object is indicated.

대표청구항 ▼

A method of detecting defects in objects such as photomasks, reticles, wafers, printed circuit boards, and the like, comprising the steps of: inspecting a selected surface area of an object and generating a first stream of data having signal values representing the image content of each pixel thereo

A method of detecting defects in objects such as photomasks, reticles, wafers, printed circuit boards, and the like, comprising the steps of: inspecting a selected surface area of an object and generating a first stream of data having signal values representing the image content of each pixel thereof; generating a second stream of data having signal values representing the image content of each pixel of said second stream of data; storing corresponding portions of the first and second streams of data in memory; detecting with a resolution to a fraction of a pixel any misalignment between the stored portions of said first and second streams of data; aligning the stored first and second portions of data using subpixel interpolation to correct any detected misalignment therebetween; and comparing corresponding subportions of the stored and aligned first and second portions of data to detect differences therebetween, and upon detecting a difference, indicating the presence of a defect at a particular pixel location on the inspected object.