High-sensitivity optical scanning using memory integration

• US 20030006364A1
• Filed: 06/21/2002
• Published: 01/09/2003
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Orbotech Limited (KLA Corporation)
• Original Assignee: Orbotech Limited (KLA Corporation)
• Inventors: Katzir, Yigal, Gur-Arie, Itay, Malinovich, Yacov
• Granted Patent: US 7,009,163 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002
• CPC Class Codes: G01N 21/8901 Optical details; Scanning details per se G02B
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/768 for time delay and integration [TDI]
• CPC Class Codes: H04N 25/772 comprising A/D, V/T, V/F, I/T or I/F converters
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

An inspection system includes a CMOS integrated circuit having integrally formed thereon an at least two dimensional array of photosensors and providing an inspection output representing an object to be inspected. A defect analyzer is operative to receive the inspection output and to provide a defect report.

Claims

1. An inspection system comprising:

a CMOS integrated circuit having integrally formed thereon an at least two dimensional array of photosensors and providing an inspection output representing an object to be inspected; and

a defect analyzer operative to receive said inspection output and to provide a defect report.

2. The inspection system claimed claim 1 and further comprising a scanner having a support assembly supporting said object to be inspected and wherein said CMOS integrated circuit is operative to acquire a plurality of images of said object during scanning thereof.

3. The inspection system claimed in claim 2 and wherein said plurality of images comprises a plurality of digital images.

4. The inspection system claimed in claim 2 and wherein said plurality of images comprises a first plurality of images associated with a first color spectrum and a second plurality of images associated with a second color spectrum.

5. The inspection system claimed in claim 2 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images.

6. The image system claimed in claim 2 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images by a single row of pixels generated by said at least two dimensional array of photosensors.

7. The inspection system claimed in claim 5 and wherein said CMOS integrated circuit includes a composite image generator operative to generate a composite image of said object by combining said plurality of images.

8. The inspection system claimed in claim 1 and further comprising an illumination assembly generally continuously illuminating said object to be inspected and wherein said CMOS integrated circuit is operative to acquire multiple images of said object during illumination thereof.

9. The inspection system claimed in claim 2 and further comprising an illumination assembly generally continuously illuminating said object to be inspected and wherein said CMOS integrated circuit is operative to acquire said plurality of images during illumination of said object.

10. The inspection system claimed in claim 5 and further comprising an illumination assembly generally continuously illuminating said object to be inspected and wherein said CMOS integrated circuit is operative to acquire said plurality of images during illumination of said object.

11. The inspection system claimed in claim 1 and wherein said CMOS integrated circuit has integrally formed thereon, in addition to said at least two dimensional array of photosensors, at least one A/D converter receiving outputs from said at least two dimensional array of photosensors.

12. The inspection system claimed in claim 11 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

13. The inspection system claimed in claim 11 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

14. The inspection system claimed in claim 11 and wherein said CMOS integrated circuit has additionally integrally formed thereon a plurality of digital registers temporarily storing the outputs of said A/D converters.

15. The inspection system claimed in claim 14 and wherein said CMOS integrated circuit has additionally integrally formed thereon:

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

16. The inspection system claimed in claim 15 and wherein said digital memory comprises an array of digital memory cells.

17. The inspection system claimed in claim 15 and wherein said CMOS integrated circuit comprises timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

18. The inspection system claimed in claim 17 and wherein said CMOS integrated circuit comprises:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

19. The inspection system claimed in claim 18 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

20. The inspection system claimed in claim 7 and further comprising an image analyzer analyzing said composite image to determine defects in said object.

21. The inspection system claimed in claim 20 and wherein said object is an electrical circuit.

40. The method claimed in claim 18 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

22. A method for manufacturing electrical circuits comprising:

depositing a portion of an electrical circuit on a substrate in a given pattern; and

optically inspecting said portion to determine defects in said portion using an inspection system comprising;

a CMOS integrated circuit having integrally formed thereon an at least two dimensional array of photosensors and providing an inspection output representing an electrical circuit to be inspected; and

a defect analyzer operative to receive said inspection output and to provide a defect report.

23. The method claimed in claim 22 and wherein:

said inspection system further comprises a scanner having a support assembly supporting said electrical circuit to be inspected; and

said CMOS integrated circuit is operative to acquire a plurality of images of said electrical circuit during scanning thereof.

24. The method claimed in claim 23 and wherein said plurality of images comprises a plurality of digital images.

25. The method claimed in claim 23 and wherein said plurality of images comprises a first plurality of images associated with a first color spectrum and a second plurality of images associated with a second color spectrum.

26. The method claimed in claim 23 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images.

27. The image system claimed in claim 23 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images by a single row of pixels generated by said at least two dimensional array of photosensors.

28. The method claimed in claim 26 and wherein:

said CMOS integrated circuit includes a composite image generator operative to generate a composite image of said electrical circuit by combining said plurality of images.

29. The method claimed in claim 22 and wherein said inspection system further comprises:

an illumination assembly generally continuously illuminating said electrical circuit to be inspected and wherein said CMOS integrated circuit is operative to acquire multiple images of said electrical circuit during illumination thereof.

30. The method claimed in claim 23 and wherein:

said inspection system further comprises an illumination assembly generally continuously illuminating said electrical circuit to be inspected; and

said CMOS integrated circuit is operative to acquire said plurality of images during illumination of said electrical circuit.

31. The method claimed in claim 26 and wherein:

said inspection system further comprises an illumination assembly generally continuously illuminating said electrical circuit to be inspected; and

said CMOS integrated circuit is operative to acquire said plurality of images during illumination of said electrical circuit.

32. The method claimed in claim 22 and wherein said CMOS integrated circuit has integrally formed thereon, in addition to said at least two dimensional array of photosensors, at least one A/D converter receiving outputs from said at least two dimensional array of photosensors.

33. The method claimed in claim 32 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

34. The method claimed in claim 32 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

35. The method claimed in claim 32 and wherein said CMOS integrated circuit has additionally integrally formed thereon a plurality of digital registers temporarily storing the outputs of said A/D converters.

36. The method claimed in claim 35 and wherein said CMOS integrated circuit has additionally integrally formed thereon:

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

37. The method claimed in claim 36 and wherein said digital memory comprises an array of digital memory cells.

38. The method claimed in claim 36 and wherein said CMOS integrated circuit comprises timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

39. The method claimed in claim 38 and wherein said CMOS integrated circuit includes:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

41. An inspection system comprising:

an integrated circuit having formed thereon an at least two dimensional array of photosensors and providing a plurality of images, each image representing a portion of an object to be inspected;

a composite image generator digitally adding together said plurality of images and providing a composite image of said object to be inspected; and

a defect analyzer operative to receive said composite image and to provide a defect report.

42. The inspection system claimed claim 41 and further comprising a scanner having a support assembly supporting said object to be inspected and wherein said integrated circuit is operative to acquire said plurality of images during scanning thereof.

43. The inspection system claimed in claim 41 and wherein said plurality of images comprises a plurality of digital images.

44. The inspection system claimed in claim 41 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images.

45. The inspection system claimed in claim 44 and wherein an overlap between a first image and a second image comprises at least half of said second image.

46. The inspection system claimed in claim 44 and wherein an overlap between a first image and a second image comprises all of said second image except for a single row of pixels output by said at least two dimensional array of photosensors.

47. The inspection system claimed in claim 41 and further comprising an illumination assembly generally continuously illuminating said object to be inspected and wherein said integrated circuit is operative to acquire said plurality of images during illumination thereof.

48. The inspection system claimed in claim 41 and further comprising an illumination assembly generally non-continuously illuminating said object to be inspected, and wherein said integrated circuit is operative to acquire said plurality of images during non-continuous illumination thereof.

49. The inspection system claimed in claim 48 and wherein said illumination assembly is operative to provide said non-continuous illumination synchronously with said integrated circuit acquiring images of said object.

50. The inspection system claimed in claim 41 and wherein said integrated circuit has integrally formed thereon, in addition to said at least two dimensional array of photosensors, at least one A/D converter receiving outputs from said at least two dimensional array of photosensors.

51. The inspection system claimed in claim 50 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

52. The inspection system claimed in claim 50 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

53. The inspection system claimed in claim 50 and wherein said CMOS integrated circuit has additionally integrally formed thereon a plurality of digital registers temporarily storing the outputs of said A/D converters.

54. The inspection system claimed in claim 53 and wherein said CMOS integrated circuit has additionally integrally formed thereon:

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

55. The inspection system claimed in claim 54 and wherein said digital memory comprises an array of digital memory cells.

56. The inspection system claimed in claim 54 and wherein said CMOS integrated circuit comprises timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

57. The inspection system claimed in claim 56 and wherein said CMOS integrated circuit comprises:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

58. The inspection system claimed in claim 57 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

59. The inspection system claimed in claim 41 and wherein said integrated circuit is a CMOS integrated circuit.

60. The inspection system claimed in claim 41 and wherein said object is an electrical circuit.

61. A method for manufacturing electrical circuits comprising:

depositing a portion of an electrical circuit on a substrate in a given pattern; and

optically inspecting said portion to determine defects in said portion using an inspection system comprising;

an integrated circuit having formed thereon an at least two dimensional array of photosensors and providing a plurality of images, each image representing a portion of an object to be inspected;

a composite image generator digitally adding together said plurality of images and providing a composite image of said object to be inspected; and

a defect analyzer operative to receive said composite image and to provide a defect report.

62. The method claimed in claim 61 and wherein said inspection system further comprises:

a scanner having a support assembly supporting said object to be inspected and wherein said integrated circuit is operative to acquire said plurality of images during scanning thereof.

63. The method claimed in claim 61 and wherein said plurality of images comprises a plurality of digital images.

64. The method claimed in claim 61 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images.

65. The method claimed in claim 64 and wherein an overlap between a first image and a second image comprises at least half of said second image.

66. The method claimed in claim 64 and wherein an overlap between a first image and a second image comprises all of said second image except for a single row of pixels output by said at least two dimensional array of photosensors.

67. The method claimed in claim 61 and wherein said inspection system further comprises:

an illumination assembly generally continuously illuminating said object to be inspected and wherein said integrated circuit is operative to acquire said plurality of images during illumination thereof.

68. The method claimed in claim 61 and wherein said inspection system further comprises:

an illumination assembly generally non-continuously illuminating said object to be inspected, and wherein said integrated circuit is operative to acquire said plurality of images during non-continuous illumination thereof.

69. The method claimed in claim 68 and wherein said illumination assembly is operative to provide said non-continuous illumination synchronously with said integrated circuit acquiring images of said object.

70. The method claimed in claim 61 and wherein said integrated circuit has integrally formed thereon, in addition to said at least two dimensional array of photosensors, at least one A/D converter receiving outputs from said at least two dimensional array of photosensors.

71. The method claimed in claim 70 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

72. The method claimed in claim 70 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

73. The method claimed in claim 70 and wherein said integrated circuit has additionally integrally formed thereon a plurality of digital registers temporarily storing the outputs of said A/D converters.

74. The method claimed in claim 73 and wherein said integrated circuit has additionally integrally formed thereon:

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

75. The method claimed in claim 74 and wherein said digital memory comprises an array of digital memory cells.

76. The method claimed in claim 74 and wherein said integrated circuit comprises timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

77. The method claimed in claim 76 and wherein said integrated circuit further comprises:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

78. The method claimed in claim 77 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

79. The method claimed in claim 61 and wherein said integrated circuit is a CMOS integrated circuit.

80. A method for inspecting objects comprising:

acquiring a plurality of substantially overlapping images each representing a portion of an object to be inspected;

digitally adding together said images to provide a composite image of said object; and

analyzing said composite image to detect defects in said object.

81. The method claimed in claim 80 and wherein said acquiring comprises acquiring said images with a CMOS integrated circuit.

82. The method claimed in claim 80 and wherein said acquiring comprises acquiring images of an electrical circuit.

83. The method claimed in claim 80 and wherein said acquiring further comprises illuminating said object using generally continuous illumination.

84. The method claimed in claim 80 and wherein said acquiring further comprises:

acquiring said images at a frame rate; and

illuminating said object using generally non-continuous illumination fluctuating at a intensity fluctuation rate synchronized with said frame rate.

85. The method claimed in claim 80 and wherein said digitally adding comprises converting an image from an analog format to a digital format.

86. The method claimed in claim 85 and wherein said digitally adding comprises:

retrieving a previously acquired image from a memory;

digitally adding a portion of a newly acquired image in a digital format to a portion of said previously acquired image; and

returning to memory an image resulting from said digitally adding a portion.

87. A method for manufacturing electrical circuits comprising:

depositing a pattern of conductors on an electrical circuit substrate;

acquiring a plurality of substantially overlapping images each representing a portion of said pattern;

digitally adding together said images to provide a composite image of said pattern; and

analyzing said composite image to detect defects in said pattern.

88. The method claimed in claim 87 and wherein said acquiring comprises acquiring said images with a CMOS integrated circuit.

89. The method claimed in claim 87 and wherein said acquiring further comprises illuminating said electrical circuit substrate using generally continuous illumination.

90. The method claimed in claim 87 and wherein said acquiring further comprises:

acquiring said images at a frame rate; and

illuminating said electrical circuit substrate using generally non-continuous illumination fluctuating at a intensity fluctuation rate synchronized with said frame rate.

91. The method claimed in claim 87 and wherein said digitally adding comprises converting an image from an analog format to a digital format.

92. The method claimed in claim 91 and wherein said digitally adding comprises:

retrieving a previously acquired image from a memory;

digitally adding a portion of a newly acquired image in a digital format to a portion of said previously acquired image; and

returning to memory an image resulting from said digitally adding a portion.

93. An imaging system comprising:

an integrated circuit having formed thereon an at least two dimensional array of photosensors and providing a plurality of images, each image representing a partially overlapping portion of an object to be imaged; and

a composite image generator digitally adding together said plurality of images and providing a composite image of said object.

94. The imaging system claimed claim 93 and further comprising a scanner having a support assembly supporting said object to be inspected and wherein said integrated circuit is operative to acquire said plurality of images during scanning thereof.

95. The imaging system claimed in claim 93 and wherein said plurality of images comprises a plurality of digital images.

96. The imaging system claimed in claim 93 and wherein each image in said plurality of images at least partially overlaps another image in said plurality of images.

97. The imaging system claimed in claim 96 and wherein an overlap between a first image and a second image comprises at least half of said second image.

98. The imaging system claimed in claim 96 and wherein an overlap between a first image and a second image comprises all of said second image except for a single row of pixels output by said at least two dimensional array of photosensors.

99. The imaging system claimed in claim 93 and further comprising an illumination assembly generally continuously illuminating said object to be imaged and wherein said integrated circuit is operative to acquire said plurality of images during illumination thereof.

100. The imaging system claimed in claim 93 and further comprising an illumination assembly generally non-continuously illuminating said object to be imaged, and wherein said integrated circuit is operative to acquire said plurality of images during non-continuous illumination thereof.

101. The imaging system claimed in claim 100 and wherein said illumination assembly is operative to provide said non-continuous illumination synchronously with said integrated circuit acquiring images of said object.

102. The imaging system claimed in claim 93 and wherein said integrated circuit has integrally formed thereon, in addition to said at least two dimensional array of photosensors, at least one A/D converter receiving outputs from said at least two dimensional array of photosensors.

103. The imaging system claimed in claim 102 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

104. The imaging system claimed in claim 102 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

105. The imaging system claimed in claim 102 and wherein said integrated circuit has additionally integrally formed thereon a plurality of digital registers temporarily storing the outputs of said A/D converters.

106. The imaging system claimed in claim 105 and wherein said integrated circuit has additionally integrally formed thereon:

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

107. The imaging system claimed in claim 106 and wherein said digital memory comprises an array of digital memory cells.

108. The imaging system claimed in claim 106 and wherein said integrated circuit comprises timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

109. The imaging system claimed in claim 108 and wherein said integrated circuit comprises:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

110. The imaging system claimed in claim 109 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

111. The imaging system claimed in claim 93 and wherein said integrated circuit is a CMOS integrated circuit.

112. The imaging system claimed in claim 93 and wherein said object is an electrical circuit.

114. The method claimed in claim 113 and wherein said acquiring comprises scanning an at least two dimensional array of photosensors relative to said object.

115. The method claimed in claim 114 and wherein said acquiring comprises acquiring said images using an at least two dimensional array of photosensors disposed on a CMOS integrated circuit.

116. The method claimed in claim 113 and wherein said acquiring comprises acquiring said images using an at least two dimensional array of photosensors disposed on a CMOS integrated circuit.

117. The method claimed in claim 113 and wherein said acquiring comprises acquiring images of an electrical circuit.

118. The method claimed in claim 113 and wherein said acquiring further comprises illuminating said object using generally continuous illumination.

119. The method claimed in claim 113 and wherein said acquiring further comprises:

acquiring said images at a frame rate; and

illuminating said object using generally non-continuous illumination fluctuating at an intensity fluctuation rate synchronized with said frame rate.

120. The method claimed in claim 113 and wherein said digitally adding comprises converting an image from an analog format to a digital format.

121. The method claimed in claim 120 and wherein said digitally adding comprises:

retrieving a previously acquired image from a memory;

digitally adding a portion of a newly acquired image in a digital format to a portion of said previously acquired image; and

returning to memory an image resulting from said digitally adding a portion.

123. The single chip integrated circuit claimed in claim 122 and wherein said at least one A/D converter comprises an A/D converter associated with each photosensor in said array.

124. The single chip integrated circuit claimed in claim 122 and wherein said at least one A/D converter comprises an A/D converter associated with a plurality of photosensors.

125. The single chip integrated circuit claimed in claim 122 and wherein said digital memory comprises an array of digital memory cells.

126. The single chip integrated circuit claimed in claim 122 and further comprising timing circuitry associated with said array, said adders and said digital memory, said timing circuitry generating a sequence of clock cycles.

127. The single chip integrated circuit claimed in claim 126 and further comprising:

an input pointer indicating at each clock cycle a location in said digital memory at which to add an output of said at least one A/D converters; and

an output pointer indicating at each clock cycle a location in said digital memory from which to retrieve said image data.

128. The single chip integrated circuit claimed in claim 127 and wherein said clock is operative to change a location of said input pointer and to change a location of said output pointer at each clock cycle.

130. A device according to claim 129, wherein the timing circuitry is further adapted to generate an output pointer and to advance the output pointer in the successive cycles of the array clock so that at each cycle of the array clock, the summed signal values are read out of the cells in one of the memory rows that is indicated by the output pointer.

131. A device according to claim 130, wherein the timing circuitry is adapted to control the input and output pointers so that the summed signal values read out at each cycle of the array clock are summed over a predetermined number of the sensor elements.

132. A device according to claim 130, wherein the radiation incident on the sensor elements is received from an object that is in motion relative to the device, and wherein the timing circuitry is adapted to generate the array clock in synchronization with the motion, so that the summed signal values read out of the cells make up an image of the object.

133. A device according to claim 132, wherein the timing circuitry is adapted to select a direction in which to advance the input and output pointers in the successive cycles of the array clock responsive to the direction of the motion.

134. A device according to claim 129, wherein the sensor rows are arranged in a row order from a first row to a last row in the array, and wherein the timing circuitry is adapted to control the array so that the signal is read out of the array both in a first readout order beginning from the first row and in a second readout order beginning from the last row.

135. A device according to claim 134, wherein the timing circuitry is adapted to control the array so that the signal is read out in the first and second readout orders in alternation.

136. A device according to claim 129, wherein the timing circuitry is controllable so as to vary a direction in which the input pointer is advanced from each of the memory rows to its neighboring row in each of the clock cycles.

137. A device according to claim 129, wherein the sensor elements comprise CMOS sensor elements.

138. A device according to claim 137, wherein the CMOS sensor elements comprise active pixel sensors.

139. A device according to claim 137, wherein the array, memory, adders and timing circuitry are fabricated together on a single integrated circuit chip.

140. A device according to claim 129, and comprising a multiplicity of analog/digital (A/D) converters, each such A/D converter coupled to receive and digitize the signal from the sensor elements in a respective one of the sensor columns, and to output the digitized signal to a corresponding one of the adders.

141. A device according to claim 140, wherein each of the adders is coupled to output the summed signal values to the memory cells in a corresponding one of the memory columns.

142. A device according to claim 129, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to radiation incident thereon in a respective wavelength band, selected from among multiple wavelength bands that the array is configured to receive.

144. A device according to claim 143, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band.

145. A device according to claim 144, wherein the timing circuitry is adapted to generate an input pointer for each of the wavelength bands, such that at each cycle of the array clock, the signal from the sensor elements in each of the sensor rows is summed by the adders with the stored signal value in the cells in a respective one of the memory rows that is determined by the input pointer for the respective wavelength band.

146. A device according to claim 145, wherein the timing circuitry is adapted to advance the input pointer for each of the wavelength bands in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns.

147. A device according to claim 146, wherein the timing circuitry is further adapted to generate an output pointer for each of the wavelength bands and to advance the output pointer for each of the wavelength bands in the successive cycles of the array clock so that at each cycle of the array clock, the summed signal values for each of the wavelength bands are read out of the cells in one of the memory rows that is indicated by the output pointer.

148. A device according to claim 144, wherein the sensor rows are arranged in two or more groups, each of the groups comprising two or more mutually-adjacent rows, such that the sensor elements in each of the groups are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band.

149. A device according to claim 144, wherein the sensor rows are arranged so that each of the sensor rows has a different respective wavelength band from the other sensor rows that are adjacent to it.

150. A device according to claim 149, wherein the radiation incident on the sensor elements is received from an object, and wherein the summed signal values make up a multiple-wavelength image of the object, and wherein the timing circuitry is adapted to control the array so that the sensor elements in two or more of the adjacent sensor rows receive the radiation from a common point on the object simultaneously during one of the clock cycles.

151. A device according to claim 149, wherein the radiation incident on the sensor elements is received from an object, and wherein the summed signal values make up a multiple-wavelength image of the object, and wherein the timing circuitry is adapted to control the array so that the sensor elements in the adjacent sensor rows receive the radiation from a given point on the object in successive clock cycles.

152. A device according to claim 143, wherein the radiation incident on the sensor elements is received from an object that is in motion relative to the device, and wherein the timing circuitry is adapted to generate the array clock in synchronization with the motion, so that the summed signal values read out of the cells make up an image of the object.

153. A device according to claim 143, wherein the sensor elements comprise CMOS sensor elements.

154. A device according to claim 153, wherein the CMOS sensor elements comprise active pixel sensors.

155. A device according to claim 153, wherein the array, memory, adders and timing circuitry are fabricated together on a single integrated circuit chip.

157. Apparatus according to claim 156, wherein the timing circuitry is adapted to generate the array clock in synchronization with the translational motion.

158. Apparatus according to claim 156, wherein the scanning device is adapted to cause the imaging device to scan over the object in first and second opposing directions, parallel to the sensor columns, and wherein the timing circuitry is adapted to select a direction in which to advance the input pointer in the successive cycles of the array clock responsive to the direction of the scan.

161. A method according to claim 160, and comprising:

generating an output pointer;

at each cycle of the array clock, reading out the summed signal values from the cells in one of the memory rows that is indicated by the output pointer; and

advancing the output pointer in the successive cycles of the array clock.

162. A method according to claim 161, wherein advancing the input and output pointers comprises controlling the input and output pointers so that the summed signal values read out at each cycle of the array clock are summed over a predetermined number of the sensor elements.

163. A method according to claim 161, wherein the radiation incident on the sensor elements is received from an object that is in motion relative to the method, and wherein generating the array clock comprises synchronizing the array clock with the motion, so that the summed signal values read out of the cells make up an image of the object.

164. A method according to claim 163, wherein advancing the input and output pointers comprises selecting a direction in which to advance the input and output pointers in the successive cycles of the array clock responsive to the direction of the motion.

165. A method according to claim 160, wherein the sensor rows are arranged in a row order from a first row to a last row in the array, and wherein summing the signal output by the sensing elements comprises reading the signal out of the array both in a first readout order beginning from the first row and in a second readout order beginning from the last row.

166. A method according to claim 165, wherein reading the signal out of the array comprises controlling the array so that the signal is read out in the first and second readout orders in alternation.

167. A method according to claim 160, wherein advancing the input pointer comprises varying a direction in which the input pointer is advanced from each of the memory rows to its neighboring row in the successive cycles of the array clock.

168. A method according to claim 160, wherein summing the signal comprises digitizing the signal output by the sensing elements using multiple analog/digital (A/D) converters, each such A/D converter receiving and digitizing the signal from the sensor elements in a respective one of the sensor columns, and summing the digitized signal with the stored signal value.

169. A method according to claim 160, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to radiation incident thereon in a respective wavelength band, selected from among multiple wavelength bands that the array is configured to receive, and wherein generating the summed signal values comprises generating respective summed signal values for the multiple wavelength bands.

171. A method according to claim 170, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band, and comprising generating an input pointer for each of the wavelength bands, wherein summing the signal comprises summing the signal from the sensor elements in each of the sensor rows with the stored signal value in the cells in a respective one of the memory rows that is determined by the input pointer for the respective wavelength band.

172. A method according to claim 171, wherein generating the input pointer comprises advancing the input pointer for each of the wavelength bands in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns.

173. A method according to claim 172, and comprising:

generating an output pointer for each of the wavelength bands;

at each cycle of the array clock, reading out the summed signal values for each of the wavelength bands from the cells in one of the memory rows that is indicated by the output pointer; and

advancing the output pointer for each of the wavelength bands in the successive cycles of the array clock.

174. A method according to claim 170, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band, the sensor rows being arranged in two or more groups, each of the groups comprising two or more mutually-adjacent rows, such that the sensor elements in each of the groups are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band, and wherein summing the signal comprises summing the signal output by the sensor elements in the mutually-adjacent rows in each of the groups.

175. A method according to claim 170, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band, the sensor rows being arranged so that each of the sensor rows has a different respective wavelength band from the other sensor rows that are adjacent to it, and wherein the radiation incident on the sensor elements is received from an object, so that the summed signal values make up a multiple-wavelength image of the object, and wherein generating the array clock comprises controlling the array so that the sensor elements in two or more of the adjacent sensor rows receive the radiation from a common point on the object simultaneously during one of the clock cycles.

176. A method according to claim 170, wherein the sensor elements in each of the sensor rows are adapted to output the signal responsive to the radiation incident thereon in the same respective wavelength band, the sensor rows being arranged so that each of the sensor rows has a different respective wavelength band from the other sensor rows that are adjacent to it, and wherein the radiation incident on the sensor elements is received from an object, so that the summed signal values make up a multiple-wavelength image of the object, and wherein generating the array clock comprises controlling the array so that the sensor elements in the adjacent sensor rows receive the radiation from a given point on the object in successive clock cycles.

177. A method according to claim 170, wherein the radiation incident on the sensor elements is received from an object that is in motion relative to the method, and wherein generating the array clock comprises synchronizing the array clock with the motion, so that the summed signal values read out of the cells make up an image of the object.

179. A method according to claim 178, wherein generating the array clock comprises synchronizing the array clock with the scanning of the array.

180. A method according to claim 178, wherein scanning the array comprises reversing a direction of scanning the array over the object, and wherein advancing the pointer comprises reversing the direction of advancing the pointer in the successive cycles of the array clock responsive to the direction of the scan.

113. A method for imaging objects comprising:

acquiring a plurality of substantially overlapping images each representing a portion of an object to be imaged; and

digitally adding together said images to provide a composite image of said object.

122. A single chip integrated circuit suitable for use in an imaging system and comprising:

a CMOS integrated circuit having integrally formed thereon;

an at least two dimensional array of photosensors;

at least one A/D converter receiving outputs from said at least two dimensional array of photosensors;

a plurality of digital registers temporarily storing the outputs of said A/D converters;

a digital memory storing image data provided by said array; and

a plurality of digital adders adding the outputs of said digital registers to corresponding image data stored in said digital memory.

129. An imaging device, comprising:

an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation incident thereon;

a memory, comprising memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

one or more adders, adapted to sum the signal output by the sensing elements with the signal value stored in the memory cells; and

timing circuitry, coupled to control the array, memory and adders, and adapted to generate an input pointer and an array clock having clock cycles, such that at each cycle of the array clock, the signal from the sensor elements in each of the sensor rows is summed by the adders with the stored signal value in the cells in a respective one of the memory rows that is determined by the input pointer, thus generating summed signal values that are stored in the memory cells, the timing circuitry further being adapted to advance the input pointer in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns.

143. An imaging device, comprising:

an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation incident thereon in a respective wavelength band, selected from among multiple wavelength bands that the array is configured to receive;

a memory, comprising memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

one or more adders, adapted to sum the signal output by the sensing elements with the signal value stored in the memory cells; and

timing circuitry, coupled to control the array, memory and adders, and adapted to generate an array clock having clock cycles, such that at each cycle of the array clock, the signal from each of the sensor elements is summed by the adders with the stored signal value in a designated one of the memory cells, thus generating summed signal values that are stored in the memory cells, each of the summed signal values comprising a sum of the signals output by a plurality of the sensor elements in a given one of the sensor columns responsive to the radiation in one of the multiple wavelength bands, such that different ones of the memory cells contain the summed signal values for different, respective wavelength bands.

156. Apparatus for automated optical inspection of an object, comprising:

an imaging device, which comprises;

an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation from the object that is incident thereon;

a memory, comprising memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

one or more adders, adapted to sum the signal output by the sensing elements with the signal value stored in the memory cells; and

timing circuitry, coupled to control the array, memory and adders, and adapted to generate an input pointer and an array clock having clock cycles, such that at each cycle of the array clock, the signal from the sensor elements in each of the sensor rows is summed by the adders with the stored signal value in the cells in a respective one of the memory rows that is determined by the input pointer, thus generating summed signal values that are stored in the memory cells, the summed signal values corresponding to pixels in an image of the object, the timing circuitry further being adapted to advance the input pointer in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns;

a scanning device, adapted to impart translational motion to at least one of the imaging device and the object, causing the imaging device to scan over the object while the radiation is incident on the sensor elements, and while the device operates to generate the summed signal values; and

an image processor, coupled to receive the summed signal values from the memory and to analyze the values so as to evaluate a characteristic of the object.

159. Apparatus for automated optical inspection of an object, comprising:

an imaging device, comprising;

an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation from the object that is incident thereon in a respective wavelength band, selected from multiple wavelength bands that the array is configured to receive;

a memory, comprising memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

one or more adders, adapted to sum the signal output by the sensing elements with the signal value stored in the memory cells; and

timing circuitry, coupled to control the array, memory and adders, and adapted to generate an array clock having clock cycles, such that at each cycle of the array clock, the signal from each of the sensor elements is summed by the adders with the stored signal value in a designated one of the memory cells, thus generating summed signal values that are stored in the memory cells, the summed signal values corresponding to pixels in an image of the object, each of the summed signal values comprising a sum of the signals output by a plurality of the sensor elements in a given one of the sensor columns responsive to the radiation in one of the multiple wavelength bands, such that different ones of the memory cells contain the summed signal values for different, respective wavelength bands.

a scanning device, adapted to impart translational motion to at least one of the imaging device and the object, causing the imaging device to scan over the object while the radiation is incident on the sensor elements, and while the device operates to generate the summed signal values; and

an image processor, coupled to receive the summed signal values from the memory and to analyze the values so as to evaluate a characteristic of the object.

160. A method for imaging, using an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation incident thereon, and a memory, which includes memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value, the method comprising:

generating an array clock having clock cycles and an input pointer that points to one or more of the memory rows;

at each cycle of the array clock, summing the signal output by the sensing elements in each of the sensor rows with the signal value stored in the memory cells in a respective one of the memory rows that is determined by the input pointer, thus generating summed signal values that are stored in the memory cells; and

advancing the input pointer in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns.

170. A method for imaging, using an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to radiation incident thereon in a respective wavelength band, selected from among multiple wavelength bands that the array is configured to receive, and a memory, which includes memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value, the method comprising:

generating an array clock having clock cycles and an input pointer that points to one or more of the memory rows; and

at each cycle of the array clock, summing the signal output by each of the sensing elements with the signal value stored in a designated one of the memory cells, thus generating summed signal values that are stored in the memory cells, each of the summed signal values comprising a sum of the signals output by a plurality of the sensor elements in a given one of the sensor columns responsive to the radiation in one of the multiple wavelength bands, such that different ones of the memory cells contain the summed signal values for different, respective wavelength bands.

178. A method for automated optical inspection of an object, comprising:

collecting radiation from the object to impinge on an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to the radiation incident thereon;

coupling the array to a memory, which includes memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

generating an array clock having clock cycles and an input pointer that points to one or more of the memory rows;

at each cycle of the array clock, summing the signal output by the sensing elements in each of the sensor rows with the signal value stored in the memory cells in a respective one of the memory rows that is determined by the input pointer, thus generating summed signal values that are stored in the memory cells;

advancing the input pointer in successive cycles of the array clock so that the summed signal value stored in each of the memory cells comprises a sum of the signals output by a plurality of the sensing elements in a given one of the sensor columns;

scanning the array over the object while the radiation is incident on the sensor elements, and while generating the array clock, summing the signal, and advancing the input pointer, to generate the summed signal values; and

receiving and processing the summed signal values from the memory so as to evaluate a characteristic of the object.

181. A method for automated optical inspection of an object, comprising:

collecting radiation from the object to impinge on an array of sensor elements, arranged in a matrix of sensor rows and sensor columns, each such sensor element being adapted to output a signal responsive to the radiation incident thereon in a respective wavelength band, selected from multiple wavelength bands that the array is configured to receive;

coupling the array to a memory, which includes memory cells arranged in memory rows and memory columns, each such memory cell being adapted to store a signal value;

generating an array clock having clock cycles and an input pointer that points to one or more of the memory rows; and

at each cycle of the array clock, summing the signal output by each of the sensing elements with the signal value stored in a designated one of the memory cells, thus generating summed signal values that are stored in the memory cells, each of the summed signal values comprising a sum of the signals output by a plurality of the sensor elements in a given one of the sensor columns responsive to the radiation in one of the multiple wavelength bands, such that different ones of the memory cells contain the summed signal values for different, respective wavelength bands;

scanning the array over the object while the radiation is incident on the sensor elements, and while generating the array clock and summing the signal to generate the summed signal values; and

receiving and processing the summed signal values from the memory for the different wavelength bands so as to e valuate a characteristic of the object.