Method and apparatus for inspecting integrated circuit pattern
First Claim
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1. A circuit pattern inspection method comprising the steps of:
- scanning a first region of a surface of a substrate having a circuit pattern formed thereon with a primary electron beam;
detecting a signal generated secondarily from said first region by said primary electron beam;
forming an electron-beam image of said first region from the detected signal;
storing said electron-beam image of said first region;
scanning a second region of said substrate with a primary electron beam;
detecting a signal generated secondarily from said second region by said primary electron beam;
forming an electron-beam image of said second region from the detected signal;
storing said electron-beam image of said second region;
making comparison between the stored image of said first region and the stored image of said second region; and
making a judgment on a defect in said circuit pattern on said substrate from a result of the comparison;
wherein in the steps of scanning said first and second regions with said primary electron beam, said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before a contrast of said electron-beam image is substantially changed.
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Abstract
A circuit pattern inspection method and an apparatus therefor, in which the whole of a portion to be inspected of a sample to be inspected is made to be in a predetermined charged state, the portion to be inspected is irradiated with an image-forming high-density electron beam while scanning the electron beam, secondary charged particles are detected at a portion irradiated with the electron beam after a predetermined period of time from an instance when the electron beam is irradiated, an image is formed on the basis of the thus detected secondary charged particle signal, and the portion to be inspected is inspected by using the thus formed image.
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Citations
20 Claims
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1. A circuit pattern inspection method comprising the steps of:
- scanning a first region of a surface of a substrate having a circuit pattern formed thereon with a primary electron beam;
detecting a signal generated secondarily from said first region by said primary electron beam;
forming an electron-beam image of said first region from the detected signal;
storing said electron-beam image of said first region;
scanning a second region of said substrate with a primary electron beam;
detecting a signal generated secondarily from said second region by said primary electron beam;
forming an electron-beam image of said second region from the detected signal;
storing said electron-beam image of said second region;
making comparison between the stored image of said first region and the stored image of said second region; and
making a judgment on a defect in said circuit pattern on said substrate from a result of the comparison;
wherein in the steps of scanning said first and second regions with said primary electron beam, said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before a contrast of said electron-beam image is substantially changed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- scanning a first region of a surface of a substrate having a circuit pattern formed thereon with a primary electron beam;
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9. A circuit pattern inspection method comprising the steps of:
- scanning a first region of a surface of a substrate having a circuit pattern formed thereon with a primary electron beam;
detecting a signal generated secondarily from said first region by said primary electron beam;
forming an electron beam-image of said first region from the detected signal;
storing said electron-beam image of said first region;
scanning a second region of said substrate with a primary electron beam;
detecting a signal generated secondarily from said second region by said primary electron beam;
forming an electron-beam image of said second region from the detected signal;
storing said electron-beam image of said second region;
making comparison between the image of said first region and the image of said second region; and
making a judgment on a defect in said circuit pattern on said substrate from a result of the comparison;
wherein said method further comprises the step of applying a zero or negative potential to a sample, or a sample stage, or to a vicinity of said sample and adjusting the applied voltage to thereby control radiation energy of said electron beam onto said sample substrate in the steps of scanning said first and second regions with said primary electron beam, said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before electric potential of said surface is substantially changed.
- scanning a first region of a surface of a substrate having a circuit pattern formed thereon with a primary electron beam;
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10. A circuit pattern inspection apparatus comprising:
- an electron source for generating a primary electron beam;
a lens means for converging said primary electron beam;
a sample stage for mounting a sample thereon;
a carrying means for carrying a sample to a sample chamber containing said sample stage;
a primary electron beam scanning means for making said converged primary electron beam perform scanning on a sample;
means for detecting secondary charged particles secondarily generated from said sample;
means for forming an image on the basis of a signal from said detector and storing the thus formed image;
means for comparing the image of a concerned region which is stored in said storage means, with another image of another region in which another same circuit pattern is formed; and
means for judging a defect in said circuit pattern from a result of the comparison;
wherein said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before electric potential of said surface is substantially changed. - View Dependent Claims (11)
- an electron source for generating a primary electron beam;
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12. A circuit pattern inspection apparatus, comprising:
- an electron source for generating a primary electron beam;
a lens means for converging said primary electron beam;
a sample stage for mounting a sample thereon;
a carrying means for carrying a sample to a sample chamber containing said sample stage;
a primary electron beam scanning means for making said converged primary electron beam perform scanning on a sample;
means for detecting secondary charged particles secondarily generated from said sample;
means for forming an image on the basis of a signal from said detector and storing the thus formed image;
means for comparing the image of a concerned region, which is stored in said storage means, with another image of another region in which another same circuit pattern is formed; and
means for judging a defect in said circuit pattern from a result of the comparison;
wherein said primary electron beam scanning means is means for performing scanning once with said primary electron beam. - View Dependent Claims (13, 14)
- an electron source for generating a primary electron beam;
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15. A circuit pattern inspection apparatus comprising:
- an electron source for generating a primary electron beam;
a lens means for converging said primary electron beam;
a sample stage for mounting a sample thereon;
a carrying means for carrying a sample to a sample chamber containing said sample stage;
a primary electron beam scanning means for making said converged primary electron beam perform scanning on a sample;
means for detecting secondary charged particles secondarily generated from said sample;
means for forming an image on the basis of a signal from said detector and storing the thus formed image;
means for comparing the image of a concerned region, which is stored in said storage means, with another image of another region in which another same circuit pattern is formed; and
means for judging a defect in said circuit pattern from a result of the comparison;
wherein said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before a contrast of said electron-beam image is substantially changed.
- an electron source for generating a primary electron beam;
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16. A circuit pattern inspection apparatus comprising:
- an electron source for generating a primary electron beam;
an object lens for converging said primary electron beam;
a sample stage for mounting a sample thereon;
a carrier for carrying a sample to a sample chamber containing said sample stage;
a scanning deflector for making said converged primary electron beam perform scanning on a sample;
a detector for detecting secondary charged particles secondarily generated from said sample;
a unit for forming an image on the basis of a signal from said detector and storing the thus formed image;
a comparator for comparing the image of a concerned region, which is stored in said unit, with another image of another region in which another same circuit pattern is formed; and
a system coupled to judge a defect in said circuit pattern from a result of the comparison;
wherein said electron-beam image of a target region is formed by scanning with said electron beam in a manner so that said secondarily generated signal is detected at a time when electric charges due to the electron beam begin to be accumulated on the surface of the substrate and before a contrast of said electron-beam image is substantially changed.
- an electron source for generating a primary electron beam;
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17. A circuit pattern inspection apparatus comprising:
- an electron source for generating a primary electron beam;
an object lens for converging said primary electron beam;
a sample stage for mounting a sample thereon;
a carrier for carrying a sample to a sample chamber containing said sample stage;
a scanning deflector for making said converged primary electron beam perform scanning on a sample;
a detector for detecting secondary charged particles secondarily generated from said sample;
a unit for forming an image on the basis of a signal from said detector and storing the thus formed image;
a comparator for comparing the image of a concerned region, which is stored in said unit, with another image of another region in which another same circuit pattern is formed; and
a system coupled to judge a defect in said circuit pattern from a result of the comparison;
wherein said scanning deflector is means for performing scanning once with said primary electron beam.
- an electron source for generating a primary electron beam;
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18. A circuit pattern inspection apparatus comprising:
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an electron source, a sample stage for mounting a sample thereon, an electronic optical system for irradiating said sample with an electron beam from said electron source, and a memory for storing information obtained by scanning a concerned region on said sample only one time, wherein a defect on said sample is inspected on the basis of said information stored in the memory and information obtained by scanning another region on said sample only one time. - View Dependent Claims (19)
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20. A circuit pattern inspection apparatus comprising:
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an electron source, a sample stage for mounting a sample thereon, an electronic optical system for irradiating said sample with an electron beam from said electron source, and a memory for storing information obtained by scanning a concerned region on said sample and another region on said sample once, respectively, wherein said information includes information of first and second patterns, and wherein a defect on said sample is extracted from said information of said first and second patterns stored in the memory.
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Specification