Automatic high speed optical inspection system
First Claim
1. Inspection apparatus for inspecting surface features of a substrate comprising:
- memory means for storing the desired features of the surface of the substrate;
illumination means for critical illumination of a region of the surface of the substrate to be inspected;
TDI sensor means for imaging the region of the substrate illuminated by the illumination means; and
comparison means responsive to the memory and TDI sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate.
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Accused Products
Abstract
In each configuration, at least one TDI sensor is used to image the portions of interest of the substrate that are substantially uniformly or critically illuminated. In one configuration, the substrate is compared to the expected characteristic features prestored in memory. In a second configuration, a first and second pattern in a region of at least one substrate are inspected by comparing one pattern against the other and noting whether they agree with each other. This is accomplished by illuminating the two patterns, imaging the first pattern and storing its characteristics in a temporary memory, then imaging the second pattern and comparing it to the stored characteristics from the temporary memory. Then the comparisons continue sequentially with the second pattern becoming the first pattern in the next imaging/comparison sequence against a new second pattern. With each comparison whether there has been agreement between the two patterns is noted. After all of the patterns are sequentially compared, the bad ones are identified by identifying those that did not compare with other patterns in the test process. This inspection technique is useful for doing die-to-die inspections, as well as repeating patern inspections within the same die. A variation of the second configuration uses two TDI sensors to simultaneously image the first and second patterns eliminating the need for the temporary memory.
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Citations
56 Claims
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1. Inspection apparatus for inspecting surface features of a substrate comprising:
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memory means for storing the desired features of the surface of the substrate; illumination means for critical illumination of a region of the surface of the substrate to be inspected; TDI sensor means for imaging the region of the substrate illuminated by the illumination means; and comparison means responsive to the memory and TDI sensor means for comparing the imaged region of the substrate with the stored desired features of the substrate. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for inspecting surface features of a substrate, said method comprising the steps of:
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a. storing the desired features on the surface of the substrate; b. illuminating by means for critical illumination a region of the surface of the substrate to be inspected; c. imaging the region of the substrate illuminated with a TDI sensor; and d. comparing the imaged region of the substrate with the stored desired features of the substrate. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for inspecting surface features of a substrate, said method comprising the steps of:
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a. illuminating by means of critical illumination at least a first pattern in a region of the surface of the substrate to be inspected; b. imaging a first pattern in the illuminated region of the substrate illuminated in step a. with a TDI sensor; c. storing the imaged pattern of step b.; d. illuminating by means of critical illumination at least a second pattern in a region of the surface of the substrate to be inspected; e. imaging a second pattern in the illuminated region of the substrate illuminated in step d. with a TDI sensor; and f. comparing the imaged second pattern of step e. with the first pattern stored in step c. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for inspecting surface features of a substrate, said method comprising the steps of:
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a. illuminating by means of substantially uniform illumination at least a first pattern in a region of the surface of the substrate to be inspected; b. imaging a first pattern in the illuminated region of the substrate illuminated in step a. with a TDI sensor; c. storing the imaged pattern of step b.; d. illuminating by means of substantially uniform illumination at least a second pattern in a region of the surface of the substrate to be inspected; e. imaging a second pattern in the illuminated region of the substrate illuminated in step d. with a TDI sensor; and f. comparing the imaged second pattern of step e. with the image of the first pattern stored in step c. - View Dependent Claims (20, 21, 22)
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23. A method for inspecting surface features of a substrate, said method comprising the steps of:
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a. illuminating by means of critical illumination at least a first and second pattern of the surface of the substrate to be inspected; b. simultaneously imaging the first and second pattern in the illuminated region of the substrate illuminated in step a. with a first and a second TDI sensor, respectively; c. comparing the imaged first and second patterns of step b. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A method for inspecting surface features of a substrate, said method comprising the steps of:
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a. illuminating by means of substantially uniform illumination at least a first and second pattern of the surface of the substrate to be inspected; b. simultaneously imaging the first and second pattern in the illuminated region of the substrate illuminated in step a. with a first and a second TDI sensor, respectively; c. comparing the imaged first and second patterns of step b. - View Dependent Claims (30, 31, 32, 33, 34)
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35. Inspection apparatus for inspecting surface features of a substrate comprising:
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illumination means for critical illumination of a first and second pattern in a region of the surface of at least one substrate to be inspected; TDI sensor means for sequentially imaging said first and second patterns; memory means for storing the imaged first pattern as that pattern is imaged by said TDI sensor means; and comparison means responsive to the memory and TDI sensor means for comparing the imaged second pattern with the first pattern stored in the memory means. - View Dependent Claims (36, 37, 38, 39, 40)
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41. Inspection apparatus for inspecting surface features of a substrate comprising:
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illumination means for substantially uniform illumination of a first and second pattern in a region of the surface of at least one substrate to be inspected; TDI sensor means for sequentially imaging said first and second patterns; memory means for storing the imaged first pattern as that pattern is imaged by said TDI sensor means; and comparison means responsive to the memory and TDI sensor means for comparing the imaged second pattern with the image of the first pattern stored in the memory means. - View Dependent Claims (42, 43, 44)
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45. Inspection apparatus for inspecting surface features of a substrate comprising:
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illumination means for the simultaneous critical illumination of a first and second pattern in a region of the surface of at least one substrate to be inspected; a pair of TDI sensor means for sequentially imaging said first and second patterns; and comparison means responsive to said pair of TDI sensor means for comparing the imaged first and second patterns. - View Dependent Claims (46, 47, 48, 49, 50)
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51. Inspection apparatus for inspecting surface features of a substrate comprising:
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illumination means for the simultaneous substantially uniform illumination of a first and second pattern in a region of the surface of at least one substrate to be inspected; a pair of TDI sensor means for sequentially imaging said first and second patterns; and comparison means responsive to said pair of TDI sensor means for comparing the imaged first and second patterns. - View Dependent Claims (52, 53, 54, 55, 56)
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Specification