Patent EP0214436A2 successfully refreshed from Google Patents.
EP0214436A2
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Method and apparatus for detecting defect information in a holographic image pattern
Assignee: Applied Materials Inc
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Filing: 1986-07-28
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Granted: —
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Expires: 2006-07-28
Abstract
Abstract A method and an apparatus detect in a light pattern the presence of defects (l0') in a photomask (l0) to which the light pattern corresponds. An inspection area (36) that includes the light pattern is partitioned into stripe regions (72). The width (70) of a stripe region corresponds to the maximum extent of the image window (54) of a charge-coupled camera device (42) that is employed to scan continuously each stripe region at a nominally constant speed. Each stripe region is divided into a first array (90) of pixel elements (92) arranged in rows (94) and columns (96). The camera device comprises plural light detecting elements (84) that are arranged in a second array (82) of rows (86) and columns (88). The camera continuously traverses the columns of the first array in a direction along the length of the stripe region and acquires in row-by-row fashion quantities of charge which correspond to the intensities of light present in the pixel elements with which the light detecting elements are aligned. The charge quantity measured for each pixel element in a row is shifted serially along a corresponding column of the second array in synchronism with, but in a direction opposite to, the motion of the camera device. The total charge quantity for each pixel element appears in the last row of light detecting elements. Each total charge quantity is converted to digital form by an analog-to-digital converter (222) and is then transferred to a threshold detector (224) which determines whether the quantity of light indicates the presence of a defect in the photomask.
Inventors
- 👤 Daniel L. Cavan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 08:21
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
160 words
A method of detecting in a light pattern the presence of defects in a specimen subject to which the light pattern corresponds, the light pattern comprising plural adjacent stripe regions, each stripe region including plural pixel elements arranged in a first array of rows and columns, comprising: providing a light detecting means comprising light detecting elements arranged in a second array of rows and columns, each light detecting element being operable to provide a measured energy value corresponding to the amount of light present in any one of the pixel elements; successively aligning each one of the light detecting elements in a column of the second array with a pixel element to acquire a number of the energy values that equals the number of light detecting elements in the column; accumulating the number of energy values; and determining from the accumulated energy values whether the amount of light present in the pixel element represents a defect in the specimen subject.
Claim 2
Independent Claim
160 words
A method of detecting in a light pattern the presence of defects in a specimen subject to which the light pattern corresponds, the light pattern comprising plural adjacent stripe regions, each stripe region including plural pixel elements arranged in a first array of rows and columns, comprising: providing a light detecting means comprising light detecting elements arranged in a second array of rows and columns, each light detecting element being operable to provide a measured energy value corresponding to the amount of light present in any one of the pixel elements; successively aligning each one of the light detecting elements in a column of the second array with a pixel element to acquire a number of the energy values that equals the number of light detecting elements in the column; accumulating the number of energy values; and determining from the accumulated energy values whether the amount of light present in the pixel element represents a defect in the specimen subject.
Claim 3
Independent Claim
49 words
The method of claim l in which the light pattern is stationary and the successive alignment of the light detecting elements in the column is accomplished by continuously moving the second array of light detecting elements along the light pattern stripe region in which the pixel element is located.
Claim 4
Independent Claim
96 words
The method of claim l in which each one of the light detecting elements in the column comprises a part of a charge-coupled device and produces a quantity of charge which represents an energy value, and the number of energy values are accumulated by moving the light detecting elements in the column in a direction serially past the pixel element and shifting in the opposite direction along the column the quantity of charge measured by the light detecting element in present alignment with the pixel element to the next adjacent light detecting element in the column.
Claim 5
Dependent Claim
197 words
Apparatus for detecting in a light pattern the presence of defects in a specimen subject to which the light pattern corresponds, the light pattern comprising plural adjacent stripe regions, each stripe region including a first array of pixel elements arranged in rows and columns, comprising: a light detecting means comprising light detecting elements arranged in a second array of rows and columns, each light detecting element being operable to provide a measured energy value corresponding to the amount of light present in any one of the pixel elements; scanning means to scan the light detecting means along a stripe region so that each light detecting element in one column of the second array traverses each pixel element in one column of the first array; accumulating means to accumulate for each one of the pixel elements in the one column of the first array the energy values acquired by all of the light detecting elements in the one column of the second array; and means to determine from the accumulated energy values for any one pixel element in the one column whether the amount of light in the one pixel element represents a defect in the specimen subject.
Claim 6
Dependent Claim
197 words
Apparatus for detecting in a light pattern the presence of defects in a specimen subject to which the light pattern corresponds, the light pattern comprising plural adjacent stripe regions, each stripe region including a first array of pixel elements arranged in rows and columns, comprising: a light detecting means comprising light detecting elements arranged in a second array of rows and columns, each light detecting element being operable to provide a measured energy value corresponding to the amount of light present in any one of the pixel elements; scanning means to scan the light detecting means along a stripe region so that each light detecting element in one column of the second array traverses each pixel element in one column of the first array; accumulating means to accumulate for each one of the pixel elements in the one column of the first array the energy values acquired by all of the light detecting elements in the one column of the second array; and means to determine from the accumulated energy values for any one pixel element in the one column whether the amount of light in the one pixel element represents a defect in the specimen subject.
Claim 7
Dependent Claim
15 words
The apparatus of claim 4 in which the light detecting means is a charge-coupled device.
Claim 8
Dependent Claim
41 words
The apparatus of claim 4 in which the stripe regions remain stationary and the scanning means further comprises positioning means to position the light detecting means across each one of the stationary stripe regions to scan them in a serial manner.
Claim 9
Dependent Claim
20 words
The apparatus of claim 6 in which the positioning means moves the light detecting means continuously across each stripe region.
Claim 10
Dependent Claim
122 words
The apparatus of claim 4 in which the second array has a first row and N total number of rows and which further comprises position-detecting means for detecting the position of the second array relative to the stripe region, the position-detecting means cooperating with the accumulating means so that each one of the light detecting elements in the first row of the one column never accumulates more than one energy value for any one of the pixel elements of the first array with which it becomes aligned, and each one of the light detecting elements in the Nth row of the one column has accumulated N number of energy values for any one of the pixel elements with which it becomes aligned.
Claim 11
Dependent Claim
23 words
The apparatus of claim 4 in which the light pattern is derived from reconstruction of a hologram that corresponds to the specimen pattern.
Claim 12
Dependent Claim
16 words
l0. The apparatus of claim 4 in which the specimen pattern is that of a photomask.
References Cited (Backward Citations)
No citation records indexed.
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