Scanning electron microscope
First Claim
1. A method of setting an application voltage for an electrostatic chuck provided on a sample stage of a scanning electron microscope, the method comprising:
- a testing sample mounting step of mounting on the electrostatic chuck a testing sample whose degree of warp and pattern of warp are known;
a step of detecting an attraction state of the testing sample with respect to the electrostatic chuck while increasing the application voltage for the electrostatic chuck;
an application voltage storage step of storing a critical application voltage at which the attraction state of the testing sample changed from “
bad”
to “
good”
;
an inspection target sample measuring step of measuring a flatness of an inspection target sample before the inspection target sample is transported into a processing chamber of the scanning electron microscope;
a step of detecting a degree of warp and pattern of warp of the inspection target sample from the flatness of the inspection target sample;
an application voltage setting step of setting the application voltage for the electrostatic chuck based on the degree of warp and pattern of warp of the inspection target sample and the critical application voltage stored in the application voltage storage step; and
an application voltage step in which the inspection target sample is transported into the processing chamber of the scanning electron microscope and mounted on the electrostatic chuck, and in which the application voltage that has been set in the application voltage setting step is applied.
1 Assignment
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Accused Products
Abstract
There is provided a technique that is capable of attracting a sample without making the voltage applied to an electrostatic chuck unnecessarily large. Attraction experiments with respect to the electrostatic chuck are performed using a testing sample whose degree of warp and pattern of warp are known, and a critical application voltage at which the attraction state changes from “bad” to “good” is found. When measuring an inspection target sample, the flatness of the inspection target sample is measured, and the degree of warp and pattern of warp of the inspection target sample are detected. Based on the degree of warp and pattern of warp of the inspection target sample and on the known critical application voltage, the application voltage for the electrostatic chuck is set.
14 Citations
20 Claims
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1. A method of setting an application voltage for an electrostatic chuck provided on a sample stage of a scanning electron microscope, the method comprising:
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a testing sample mounting step of mounting on the electrostatic chuck a testing sample whose degree of warp and pattern of warp are known; a step of detecting an attraction state of the testing sample with respect to the electrostatic chuck while increasing the application voltage for the electrostatic chuck; an application voltage storage step of storing a critical application voltage at which the attraction state of the testing sample changed from “
bad”
to “
good”
;an inspection target sample measuring step of measuring a flatness of an inspection target sample before the inspection target sample is transported into a processing chamber of the scanning electron microscope; a step of detecting a degree of warp and pattern of warp of the inspection target sample from the flatness of the inspection target sample; an application voltage setting step of setting the application voltage for the electrostatic chuck based on the degree of warp and pattern of warp of the inspection target sample and the critical application voltage stored in the application voltage storage step; and an application voltage step in which the inspection target sample is transported into the processing chamber of the scanning electron microscope and mounted on the electrostatic chuck, and in which the application voltage that has been set in the application voltage setting step is applied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A scanning electron microscope comprising:
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a scanning coil that scans primary electrons from an electron source; an objective lens that focuses, and irradiates a sample with, the primary electrons; a secondary electron detector that detects secondary electrons from the sample; an electrostatic chuck that holds the sample; and a control device that controls an application voltage for the electrostatic chuck, wherein on the control device and with respect to a testing sample whose degree of warp and pattern of warp are known, there is stored measurement data representing a relationship between the application voltage for the electrostatic chuck and an attraction state of the testing sample with respect to the electrostatic chuck, and when an inspection target sample is mounted on the electrostatic chuck, the application voltage for the electrostatic chuck is set based on a degree of warp and pattern of warp of the inspection target sample and the measurement data stored on the control device. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A scanning electron microscope comprising:
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a scanning coil that scans primary electrons from an electron source; an objective lens that focuses, and irradiates a sample with, the primary electrons; a secondary electron detector that detects secondary electrons from the sample; an electrostatic chuck that holds the sample; a control device that controls an application voltage for the electrostatic chuck; and an attraction state detection device that detects an attraction state of the sample with respect to the electrostatic chuck, wherein the electrostatic chuck is a bipolar electrostatic chuck comprising a main body, a circular internal electrode disposed within the main body, and a ring-shaped internal electrode disposed around the circular internal electrode, the ring-shaped internal electrode has an outer diameter that is greater than an outer diameter of the sample attracted to the electrostatic chuck, the application voltage for the electrostatic chuck is set to an optimal value capable of supporting the sample in a flat state if a position of a measurement point on an inspection target sample is located further inward than an edge of the sample, and the application voltage for the electrostatic chuck is set to a value greater than the minimum value if the position of the measurement point on the inspection target sample is at the edge of the sample. - View Dependent Claims (19, 20)
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Specification