CN112863980A - Calibration method and calibration device for characteristic dimension scanning electron microscope machine - Google Patents

Calibration method and calibration device for characteristic dimension scanning electron microscope machine Download PDF

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CN112863980A
CN112863980A CN202110006982.5A CN202110006982A CN112863980A CN 112863980 A CN112863980 A CN 112863980A CN 202110006982 A CN202110006982 A CN 202110006982A CN 112863980 A CN112863980 A CN 112863980A
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value
standard
sample
electron microscope
scanning electron
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CN112863980B (en
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罗振斌
彭超
芈健
蒋鹏
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Yangtze Memory Technologies Co Ltd
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Yangtze Memory Technologies Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
    • H01J37/153—Electron-optical or ion-optical arrangements for the correction of image defects, e.g. stigmators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/20—Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/22—Optical or photographic arrangements associated with the tube
    • H01J37/224—Luminescent screens or photographic plates for imaging ; Apparatus specially adapted therefor, e.g. cameras, TV-cameras, photographic equipment, exposure control; Optical subsystems specially adapted therefor, e.g. microscopes for observing image on luminescent screen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
    • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams

Abstract

The invention relates to a calibration method and a calibration device for a characteristic dimension scanning electron microscope machine. The calibration method of the characteristic dimension scanning electron microscope machine comprises the following steps: acquiring the previous value of the sample piece and the previous value of the standard piece; the standard value of the standard piece was calculated according to the following formula: OPALtarget＝QCtarget×OPALactual/QCactualIn the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate; scanning electron microscope platform capable of automatically calibrating characteristic dimension according to standard value of standard sheet(ii) a Acquiring a test value of a sample piece by adopting a characteristic size scanning electron microscope machine after automatic calibration; and judging whether the difference value between the test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic size scanning electron microscope machine is finished. The invention saves the calibration time, improves the calibration efficiency of the CDSEM machine, and improves the accuracy and reliability of the measurement result of the CDSEM machine.

Description

Calibration method and calibration device for characteristic dimension scanning electron microscope machine
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to a calibration method and a calibration device for a characteristic dimension scanning electron microscope machine.
Background
A CDSEM (Critical Dimension Scanning Electron Microscope) tool is an instrument used to measure the feature size of a pattern formed on a wafer during a semiconductor manufacturing process. In order to ensure the accuracy of the CDSEM and thus the accuracy of the cd measurement results of the patterns on the wafer, the CDSEM tool needs to be periodically maintained, for example, at least monthly, to meet the best performance of the tool.
In the process of maintaining and maintaining the CDSEM machine, the precision calibration of the CDSEM machine is a crucial step. The current calibration time for a CDSEM tool is about 6.5 hours, and compared to other metrology equipment, a longer calibration time results in a significantly reduced utilization of the CDSEM tool, thereby limiting the improvement of semiconductor processing efficiency.
Therefore, how to improve the calibration efficiency of the CDSEM apparatus and save the calibration time, thereby improving the efficiency of the semiconductor manufacturing process, is a technical problem to be solved.
Disclosure of Invention
The invention provides a calibration method and a calibration device for a characteristic dimension scanning electron microscope machine, which are used for solving the problem of low calibration efficiency of the characteristic dimension scanning electron microscope machine in the prior art, so as to save calibration time and improve the efficiency of semiconductor manufacturing process.
In order to solve the above problems, the present invention provides a calibration method for a characteristic dimension scanning electron microscope stage, comprising the following steps:
acquiring the previous value of the sample piece and the previous value of the standard piece;
the standard value of the standard piece was calculated according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
automatically calibrating a characteristic dimension scanning electron microscope machine according to the standard value of the standard sheet;
acquiring a test value of the sample piece by adopting a characteristic size scanning electron microscope machine after automatic calibration;
and judging whether the difference value between the test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic size scanning electron microscope machine is finished.
Optionally, the specific steps of obtaining the sample piece previous value and the standard piece previous value include:
acquiring the characteristic size of a sample pattern in a sample piece by adopting a characteristic size scanning electron microscope machine station before calibration as a previous value of the sample piece;
and acquiring the characteristic dimension of the standard pattern in the standard plate by adopting a characteristic dimension scanning electron microscope machine before calibration as a previous value of the standard plate.
Optionally, the specific step of automatically calibrating the characteristic dimension scanning electron microscope according to the standard value of the standard plate includes:
and inputting the standard value of the standard sheet into an automatic calibration program of a machine, executing the automatic calibration program by adopting the standard sheet, and automatically calibrating the machine of the scanning electron microscope with the characteristic dimension.
Optionally, the specific step of obtaining the test value of the sample piece by using the automatically calibrated characteristic dimension scanning electron microscope comprises:
and acquiring the characteristic dimension of the sample pattern in the sample sheet by adopting the characteristic dimension scanning electron microscope machine calibrated by the machine automatic calibration program to serve as the test value of the sample sheet.
Optionally, before the automatically calibrated characteristic dimension scanning electron microscope is used to obtain the test value of the sample slice, the method further includes the following steps:
and detecting whether static charges exist on the sample sheet, and if so, releasing the static charges.
Optionally, after confirming that the difference between the test value of the sample piece and the target value of the sample piece is beyond the preset range, the method further comprises the following steps:
detecting whether static charges exist on the sample sheet, and if so, releasing the static charges;
acquiring a test value of the sample piece after the static charge is released by adopting a calibrated characteristic dimension scanning electron microscope machine;
and judging whether the difference value between the test value of the sample piece after the static charge is released and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic dimension scanning electron microscope machine is finished.
Alternatively, if it is confirmed that the difference between the test value of the sample piece after releasing the electrostatic charge and the target value of the sample piece is still out of the preset range, the following steps are performed:
taking the test value of the sample wafer obtained by the calibrated characteristic dimension scanning electron microscope machine as the previous value of the sample wafer, taking the test value of the standard wafer obtained by the calibrated characteristic dimension scanning electron microscope machine as the previous value of the standard wafer, and calculating the standard value of the new standard wafer according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
automatically calibrating the characteristic dimension scanning electron microscope machine again according to the standard value of the standard sheet;
acquiring a new test value of the sample slice by adopting a characteristic dimension scanning electron microscope machine after automatic calibration again;
and judging whether the difference value between the new test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic size scanning electron microscope machine is finished.
In order to solve the above problems, the present invention further provides a calibration apparatus for a characteristic dimension scanning electron microscope stage, comprising:
the acquisition module is used for acquiring the previous value of the sample piece and the previous value of the standard piece;
the calculating module is connected with the obtaining module and used for calculating the standard value of the standard sheet according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module is connected with the calculation module and is used for automatically calibrating a characteristic dimension scanning electron microscope machine according to the standard value of the standard sheet, and the acquisition module is also used for acquiring the test value of the sample sheet by adopting the automatically calibrated characteristic dimension scanning electron microscope machine;
and the judging module is connected with the obtaining module and used for judging whether the difference value between the test value of the sample piece and the target value of the sample piece is within a preset range or not, and if so, the completion of the calibration of the characteristic size scanning electron microscope machine is confirmed.
Optionally, the obtaining module obtains the characteristic size of the sample pattern in the sample sheet by using a characteristic size scanning electron microscope platform before calibration, and the characteristic size is used as a previous value of the sample sheet; the obtaining module is also used for obtaining the characteristic size of the standard pattern in the standard plate as the previous value of the standard plate by adopting a characteristic size scanning electron microscope platform before calibration.
Optionally, the calibration module is configured to input the standard value of the standard sheet into an automatic calibration program of a machine, and execute the automatic calibration program by using the standard sheet to perform automatic calibration of a machine of a feature-size scanning electron microscope.
Optionally, the obtaining module is configured to obtain the feature size of the sample pattern in the sample sheet as the test value of the sample sheet by using the feature size scanning electron microscope calibrated by the machine automatic calibration program.
Optionally, the method further includes:
and the detection module is used for detecting whether the sample sheet has static charges or not before the acquisition module acquires the test value of the sample sheet by adopting the automatically calibrated characteristic dimension scanning electron microscope machine, and if so, releasing the static charges.
Optionally, the detecting module is further configured to detect whether there is static charge on the sample sheet again after confirming that the difference between the test value of the sample sheet and the target value of the sample sheet is beyond the preset range, and if so, release the static charge;
the acquisition module is further used for acquiring the test value of the sample piece after the static charge is released by adopting a calibrated characteristic dimension scanning electron microscope machine;
the judging module is further configured to judge whether a difference between the test value of the sample piece after the electrostatic charge is released and the target value of the sample piece is within a preset range, and if so, confirm that the calibration of the characteristic dimension scanning electron microscope machine is completed.
Optionally, after the determining module determines that the difference between the test value of the sample piece after releasing the electrostatic charge and the target value of the sample piece still exceeds the preset range, the calculating module is further configured to calculate a new standard value of the standard piece according to the following formula, with the test value of the sample piece obtained by the calibrated characteristic dimension scanning electron microscope stage as a previous value of the sample piece, and with the test value of the standard piece obtained by the calibrated characteristic dimension scanning electron microscope stage as a previous value of the standard piece:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module is also used for automatically calibrating the characteristic dimension scanning electron microscope machine again according to the standard value of the standard sheet;
the acquisition module is also used for acquiring a new test value of the sample slice by adopting the automatically calibrated characteristic dimension scanning electron microscope machine;
the judging module is further used for judging whether the difference value between the new test value of the sample piece and the target value of the sample piece is within a preset range, and if yes, the fact that the characteristic size scanning electron microscope machine calibration is completed is confirmed.
The invention provides a calibration method and a calibration device of a characteristic dimension scanning electron microscope machine, which are characterized in that a pre-value of a sample piece and a pre-value of a standard piece are obtained before the characteristic dimension scanning electron microscope machine executes an automatic calibration program, a standard value of the standard piece is obtained by calculation according to the pre-value of the sample piece, a target value of the sample piece and the pre-value of the standard piece, then the automatic calibration program is executed according to the standard value of the standard piece, and then whether a difference value between a test value of the sample piece obtained by the automatically calibrated characteristic dimension scanning electron microscope machine and the target value of the sample piece is in a preset range or not is judged to determine whether the calibration meets the requirements or not. The invention does not need manual calibration, thereby saving the calibration time and improving the calibration efficiency of the characteristic dimension scanning electron microscope machine. In addition, because the automatic calibration process is added between two sample sheet collection values, the influence of residual static charges on the sample sheet on the measurement result is reduced or even avoided, and the accuracy and the reliability of the measurement result of the characteristic dimension scanning electron microscope machine are improved.
Drawings
FIG. 1 is a flow chart of a calibration method for a characteristic dimension scanning electron microscope stage according to an embodiment of the present invention;
FIG. 2 is a block diagram of a calibration apparatus for a characteristic dimension scanning electron microscope stage according to an embodiment of the present invention.
Detailed Description
The following describes in detail embodiments of a calibration method and a calibration apparatus for a characteristic dimension scanning electron microscope according to the present invention with reference to the accompanying drawings.
The current method for calibrating a CDSEM bench (i.e., a feature size scanning electron microscope bench) is: firstly, executing an automatic calibration program in a machine table to finish an automatic calibration process; then, respectively acquiring the actual value of the sample piece and the actual value of the standard piece by using a calibrated CDSEM machine; then, manually adjusting FOV (Field Of View) parameters Of the machine table and correcting the electron beams according to the difference between the obtained actual value Of the sample slice and the target value Of the sample slice; and then, acquiring the test value of the sample piece once again by using the CDSEM machine after manual adjustment, judging whether the difference value between the acquired test value of the sample piece and the target value of the sample piece is within a preset range, and if not, performing manual adjustment again until the difference value between the test value of the sample piece acquired by the CDSEM machine and the target value of the sample piece is within the preset range.
The above calibration process has at least the following two disadvantages: on one hand, since the automatic calibration procedure itself includes calibration related to electron beam correction, when the difference between the actual value of the sample piece obtained after automatic adjustment and the target value of the sample piece exceeds the preset range, the manual adjustment process needs to perform electron beam correction again, and repeated electron beam correction can greatly increase the calibration time and affect the calibration efficiency; on the other hand, since the process of manually adjusting the FOV parameters and correcting the electron beam is relatively short in time compared to the process of executing the auto-calibration procedure, the time interval between the actual value of the acquired sample piece and the test value of the acquired sample piece is short, so that the static charges remaining on the sample piece cannot be released in time, thereby affecting the accuracy of the test result.
In order to improve the calibration efficiency of the CDSEM apparatus and improve the accuracy and reliability of the test result of the CDSEM apparatus, the present embodiment provides a calibration method of the CDSEM apparatus, and fig. 1 is a flowchart of the calibration method of the CDSEM apparatus according to the present embodiment. As shown in fig. 1, the calibration method of the CDSEM apparatus provided in the present embodiment includes the following steps:
step S11, the previous value of the sample piece and the previous value of the standard piece are acquired.
Optionally, the specific steps of obtaining the sample piece previous value and the standard piece previous value include:
acquiring the characteristic size of a sample pattern in a sample piece by using a CDSEM machine before calibration as a previous value of the sample piece;
and acquiring the characteristic size of the standard pattern in the standard wafer by adopting a CDSEM machine before calibration as a previous value of the standard wafer.
Specifically, the standard sheet has a plurality of pattern areas, and the standard pattern in a pattern area is the same as the sample pattern in the sample sheet in shape and/or arrangement. The sample sheet may be a 3D NAND semiconductor structure, and accordingly, the sample pattern in the sample sheet may be a channel hole pattern, a gate pattern, and the like, which can be selected by a person skilled in the art according to actual needs.
Step S12, calculating the standard value of the standard sheet according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetRepresenting standard sheetsStandard value, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
specifically, before calibrating the CDSEM machine, the pre-value QC of the sample wafer is obtained by the CDSEM machineactualAnd the front value OPAL of the standard tabletactualThen, the standard value of the standard piece is calculated by the formula shown above based on the previous value of the sample piece, the previous value of the standard piece, and the target value of the sample piece. For example, the original standard value of the standard plate is 500nm, when the previous value QC of the sample plate isactualAt 4020nm, the front value OPAL of the standardactualTarget value QC of the sample chip at 505nmtargetThe standard value of the standard plate is 502.5 according to the calculation of the formula, wherein the standard value is 4000 nm. Therefore, the standard value of the standard sheet obtained by calculation is different from the original standard value determined in the standard sheet manufacturing process, and compared with the mode of calibration by using the original standard value, the calibration by using the corrected standard value (i.e. the standard value of the standard sheet obtained by calculation according to the formula) is performed in the specific embodiment, so that the calibration with specific characteristics of the CDSEM machine can be considered, and a foundation is laid for improving the accuracy and reliability of subsequent CDSEM measurement. The target value of the sample piece refers to the original feature size of the sample pattern on the sample piece determined during the manufacturing process. Due to the measurement accuracy limitation of the CDSEM tool, there is a certain difference between the feature size of the sample pattern measured by the CDSEM tool and the original feature size of the sample pattern, but as long as the difference is within a preset range, the CDSEM measurement result can be considered to be accurate and reliable.
And step S13, automatically calibrating the CDSEM machine according to the standard value of the standard sheet.
Optionally, the specific step of automatically calibrating the CDSEM machine according to the standard value of the standard sheet includes:
and inputting the standard value of the standard sheet into an automatic calibration program of a machine, and executing the automatic calibration program by adopting the standard sheet to perform automatic calibration of the CDSEM machine.
Specifically, an automatic calibration program is pre-built in the CDSEM machine, after the standard value of the standard sheet is calculated through the calculating step, the automatic calibration program is loaded into the CDSEM machine, and the calculated standard value of the standard sheet is input into a corresponding working point of the automatic calibration program, for example, the calculated standard value of the standard sheet is input at a Fine Magnification (Fine Magnification), and then the automatic calibration program is executed by using the standard sheet, so as to complete the automatic calibration of the CDSEM machine. The automatic calibration procedure may be the same as the automatic calibration procedure in the CDSEM in the prior art, and this detailed description is omitted here.
And step S14, acquiring the test value of the sample piece by using the CDSEM machine after automatic calibration.
Optionally, the specific step of obtaining the test value of the sample sheet by using the CDSEM machine after automatic calibration includes:
and acquiring the characteristic size of the sample pattern in the sample sheet by adopting the CDSEM machine after the calibration of the machine automatic calibration program, and taking the characteristic size as the test value of the sample sheet.
Because the execution step of the automatic calibration program is added between the test value of the sample piece and the previous value of the sample piece, and the execution time of the automatic calibration program is relatively long, the residual static charge on the sample piece can be fully released, and the influence of the residual static charge on the accuracy of the test result when the test value of the sample piece is obtained is avoided.
In order to ensure that the static charge remaining on the sample wafer is completely removed when the test value of the sample wafer is obtained, thereby further ensuring the accuracy and reliability of the test result of the CDSEM machine, optionally, before the test value of the sample wafer is obtained by using the automatically calibrated CDSEM machine, the method further comprises the following steps:
and detecting whether static charges exist on the sample sheet, and if so, releasing the static charges.
Step S15, determining whether a difference between the test value of the sample piece and the target value of the sample piece is within a preset range, and if so, determining that the CDSEM machine calibration is completed.
The specific value of the preset range may be set according to actual requirements of a semiconductor manufacturing process, for example, according to a requirement for measurement accuracy of a CDSEM apparatus, which is not limited in the present embodiment.
Optionally, after confirming that the difference between the test value of the sample piece and the target value of the sample piece is beyond the preset range, the method further comprises the following steps:
detecting whether static charges exist on the sample sheet, and if so, releasing the static charges;
acquiring a test value of the sample piece after the static charge is released by adopting a calibrated CDSEM machine;
and judging whether the difference value between the test value of the sample piece after the static charge is released and the target value of the sample piece is within a preset range, and if so, confirming that the CDSEM machine calibration is finished.
Alternatively, if it is confirmed that the difference between the test value of the sample piece after releasing the electrostatic charge and the target value of the sample piece is still out of the preset range, the following steps are performed:
taking the test value of the sample piece acquired by the calibrated CDSEM machine as the previous value of the sample piece, taking the test value of the standard piece acquired by the calibrated CDSEM machine as the previous value of the standard piece, and calculating the standard value of the new standard piece according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
automatically calibrating the CDSEM machine again according to the standard value of the standard sheet;
acquiring a new test value of the sample sheet by adopting the CDSEM machine after automatic calibration again;
and judging whether the difference value between the new test value of the sample piece and the target value of the sample piece is within a preset range, and if so, determining that the CDSEM machine calibration is completed.
Specifically, when the difference between the test value of the sample piece obtained after one automatic calibration and the target value of the sample piece is out of the preset range, it is first necessary to determine whether the cause of the inaccurate test result is due to the residual electrostatic charge on the sample piece. The method comprises the steps of firstly detecting whether static charges exist on the sample sheet, if so, acquiring a test value of the sample sheet after the static charges are released by adopting a calibrated CDSEM machine after the residual static charges on the sample sheet are fully released, judging whether a difference value between the re-acquired test value of the sample sheet and a target value of the sample sheet is within a preset range, if so, confirming that the test result is inaccurate due to the residual static charges on the sample sheet, and finishing the calibration process of the CDSEM machine.
If the difference between the test value of the sample piece after releasing the electrostatic charge and the target value of the sample piece is confirmed to be still beyond the preset range, taking the test value of the sample piece obtained by the calibrated CDSEM machine as the previous value of the sample piece, and taking the test value of the standard piece obtained by the calibrated CDSEM machine as the previous value of the standard piece, then executing steps S12-S15 again. And circulating until the difference value between the test value of the sample piece and the target value of the sample piece is within the preset range.
Moreover, the present embodiment further provides a calibration apparatus for a CDSEM machine, and fig. 2 is a block diagram of the calibration apparatus for a CDSEM machine according to the present embodiment. The calibration apparatus of the CDSEM apparatus according to the present embodiment may be calibrated by using the calibration method of the CDSEM apparatus shown in fig. 1. As shown in fig. 2, the calibration apparatus of the CDSEM apparatus according to the present embodiment includes:
an obtaining module 20, configured to obtain a previous value of the sample sheet and a previous value of the standard sheet;
the calculating module 21 is connected to the acquiring module 20, and is configured to calculate a standard value of the standard sheet according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module 22 is connected to the calculation module 21 and is configured to automatically calibrate the CDSEM apparatus according to the standard value of the standard sheet, and the acquisition module is further configured to acquire the test value of the sample sheet by using the automatically calibrated CDSEM apparatus;
and the judging module 23 is connected to the obtaining module 22, and is configured to judge whether a difference between the test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirm that the CDSEM machine calibration is completed.
Optionally, the obtaining module 20 obtains the characteristic size of the sample pattern in the sample sheet by using a CDSEM bench before calibration as a previous value of the sample sheet; the obtaining module 20 further obtains the feature size of the standard pattern in the standard wafer as a previous value of the standard wafer by using the CDSEM station before calibration.
Optionally, the calibration module 22 is configured to input the standard value of the standard sheet into an automatic calibration program of a machine, and execute the automatic calibration program by using the standard sheet to perform automatic calibration of the CDSEM machine.
Optionally, the obtaining module 20 is configured to obtain, as the test value of the sample sheet, the characteristic size of the sample pattern in the sample sheet by using the CDSEM machine calibrated by the machine automatic calibration program.
Optionally, the calibration apparatus of the CDSEM apparatus further includes:
a detecting module 24, configured to detect whether there is electrostatic charge on the sample sheet before the obtaining module 20 obtains the test value of the sample sheet by using the CDSEM machine after automatic calibration, and if so, release the electrostatic charge.
Optionally, the detecting module 24 is further configured to detect whether there is electrostatic charge on the sample sheet again after confirming that the difference between the test value of the sample sheet and the target value of the sample sheet is beyond the preset range, and if so, release the electrostatic charge;
the obtaining module 20 is further configured to obtain a test value of the sample sheet after the electrostatic charge is released by using a calibrated CDSEM machine;
the determining module 23 is further configured to determine whether a difference between the test value of the sample sheet after the electrostatic charge is released and the target value of the sample sheet is within a preset range, and if so, determine that the CDSEM machine calibration is completed.
Optionally, the calculating module 21 is further configured to calculate a new standard value of the standard sheet according to the following formula, after the determining module 23 confirms that the difference between the test value of the sample sheet after releasing the electrostatic charge and the target value of the sample sheet still exceeds the preset range, with the test value of the sample sheet obtained by the calibrated CDSEM machine as the previous value of the sample sheet, and with the test value of the standard sheet obtained by the calibrated CDSEM machine as the previous value of the standard sheet:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module 22 is further configured to automatically calibrate the CDSEM machine again according to the standard value of the standard sheet;
the obtaining module 20 is further configured to obtain a new test value of the sample sheet by using the CDSEM machine after automatic calibration again;
the determining module 23 is further configured to determine whether a difference between the new test value of the sample sheet and the target value of the sample sheet is within a preset range, and if so, determine that the CDSEM machine calibration is completed.
In the calibration method and calibration apparatus for CDSEM station according to this embodiment, before the CDSEM station executes the automatic calibration procedure, the previous value of the sample piece and the previous value of the standard piece are obtained, the standard value of the standard piece is obtained according to the previous value of the sample piece, the target value of the sample piece, and the previous value of the standard piece, then the automatic calibration procedure is executed according to the standard value of the standard piece, and then it is determined whether the difference between the test value of the sample piece obtained by the CDSEM station after the automatic calibration and the target value of the sample piece is within the preset range, so as to determine whether the calibration meets the requirement. Because this embodiment need not to carry out manual calibration, consequently, practiced thrift calibration time, improved the calibration efficiency of CDSEM board. In addition, because the automatic calibration process is added between two sample sheet collection values, the influence of residual static charges on the sample sheets on the measurement result is reduced or even avoided, and the accuracy and the reliability of the measurement result of the CDSEM machine are improved.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (14)

1. A calibration method for a characteristic dimension scanning electron microscope machine is characterized by comprising the following steps:
acquiring the previous value of the sample piece and the previous value of the standard piece;
the standard value of the standard piece was calculated according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPresentation standardThe pre-value of the patch;
automatically calibrating a characteristic dimension scanning electron microscope machine according to the standard value of the standard sheet;
acquiring a test value of the sample piece by adopting a characteristic size scanning electron microscope machine after automatic calibration;
and judging whether the difference value between the test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic size scanning electron microscope machine is finished.
2. The method of calibrating a characteristic dimension scanning electron microscope stage according to claim 1, wherein the step of obtaining the pre-value of the sample wafer and the pre-value of the standard wafer comprises:
acquiring the characteristic size of a sample pattern in a sample piece by adopting a characteristic size scanning electron microscope machine station before calibration as a previous value of the sample piece;
and acquiring the characteristic dimension of the standard pattern in the standard plate by adopting a characteristic dimension scanning electron microscope machine before calibration as a previous value of the standard plate.
3. The method for calibrating a CD-SEM tool as claimed in claim 2, wherein the step of automatically calibrating the CD-SEM tool according to the standard value of the standard plate comprises:
and inputting the standard value of the standard sheet into an automatic calibration program of a machine, executing the automatic calibration program by adopting the standard sheet, and automatically calibrating the machine of the scanning electron microscope with the characteristic dimension.
4. The method for calibrating a CD-SEM tool of claim 3, wherein the step of obtaining the test value of the sample wafer using the automatically calibrated CD-SEM tool comprises:
and acquiring the characteristic dimension of the sample pattern in the sample sheet by adopting the characteristic dimension scanning electron microscope machine calibrated by the machine automatic calibration program to serve as the test value of the sample sheet.
5. The method for calibrating a CD-SEM tool of claim 3, wherein before the automatically calibrated CD-SEM tool is used to obtain the test value of the sample piece, the method further comprises the following steps:
and detecting whether static charges exist on the sample sheet, and if so, releasing the static charges.
6. The method for calibrating a characteristic dimension scanning electron microscope stage according to claim 1, further comprising the following steps after confirming that the difference between the test value of the sample piece and the target value of the sample piece is beyond the preset range:
detecting whether static charges exist on the sample sheet, and if so, releasing the static charges;
acquiring a test value of the sample piece after the static charge is released by adopting a calibrated characteristic dimension scanning electron microscope machine;
and judging whether the difference value between the test value of the sample piece after the static charge is released and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic dimension scanning electron microscope machine is finished.
7. The method of claim 6, wherein if the difference between the test value of the sample piece after releasing the electrostatic charge and the target value of the sample piece is determined to be still beyond the preset range, the following steps are performed:
taking the test value of the sample wafer obtained by the calibrated characteristic dimension scanning electron microscope machine as the previous value of the sample wafer, taking the test value of the standard wafer obtained by the calibrated characteristic dimension scanning electron microscope machine as the previous value of the standard wafer, and calculating the standard value of the new standard wafer according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
automatically calibrating the characteristic dimension scanning electron microscope machine again according to the standard value of the standard sheet;
acquiring a new test value of the sample slice by adopting a characteristic dimension scanning electron microscope machine after automatic calibration again;
and judging whether the difference value between the new test value of the sample piece and the target value of the sample piece is within a preset range, and if so, confirming that the calibration of the characteristic size scanning electron microscope machine is finished.
8. The utility model provides a calibrating device of characteristic dimension scanning electron microscope board which characterized in that includes:
the acquisition module is used for acquiring the previous value of the sample piece and the previous value of the standard piece;
the calculating module is connected with the obtaining module and used for calculating the standard value of the standard sheet according to the following formula:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module is connected with the calculation module and is used for automatically calibrating a characteristic dimension scanning electron microscope machine according to the standard value of the standard sheet, and the acquisition module is also used for acquiring the test value of the sample sheet by adopting the automatically calibrated characteristic dimension scanning electron microscope machine;
and the judging module is connected with the obtaining module and used for judging whether the difference value between the test value of the sample piece and the target value of the sample piece is within a preset range or not, and if so, the completion of the calibration of the characteristic size scanning electron microscope machine is confirmed.
9. The apparatus for calibrating a cs stage according to claim 8, wherein the obtaining module obtains the characteristic dimension of the sample pattern in the sample sheet as the previous value of the sample sheet by using the pre-calibration cs stage; the obtaining module is also used for obtaining the characteristic size of the standard pattern in the standard plate as the previous value of the standard plate by adopting a characteristic size scanning electron microscope platform before calibration.
10. The apparatus of claim 9, wherein the calibration module is configured to input the standard value of the standard plate into an automatic calibration program of the machine, and perform the automatic calibration program using the standard plate to perform automatic calibration of the machine of the CD SEM.
11. The apparatus of claim 9, wherein the obtaining module is configured to obtain the feature size of the sample pattern in the sample sheet as the test value of the sample sheet by using the stage of the sem calibrated by the stage auto-calibration procedure.
12. The apparatus for calibrating a characteristic dimension scanning electron microscope stage according to claim 9, further comprising:
and the detection module is used for detecting whether the sample sheet has static charges or not before the acquisition module acquires the test value of the sample sheet by adopting the automatically calibrated characteristic dimension scanning electron microscope machine, and if so, releasing the static charges.
13. The apparatus for calibrating a stage of a sem as claimed in claim 12, wherein the detecting module is further configured to detect whether there is static charge on the sample sheet again after confirming that the difference between the test value of the sample sheet and the target value of the sample sheet is beyond the preset range, and if so, to discharge the static charge;
the acquisition module is further used for acquiring the test value of the sample piece after the static charge is released by adopting a calibrated characteristic dimension scanning electron microscope machine;
the judging module is further configured to judge whether a difference between the test value of the sample piece after the electrostatic charge is released and the target value of the sample piece is within a preset range, and if so, confirm that the calibration of the characteristic dimension scanning electron microscope machine is completed.
14. The apparatus for calibrating a cd-sem stand of claim 13, wherein the calculating module is further configured to calculate the standard value of a new standard sheet according to the following formula, after the determining module confirms that the difference between the test value of the sample sheet after releasing the electrostatic charge and the target value of the sample sheet still exceeds the preset range, with the test value of the sample sheet obtained by the calibrated cd-sem stand as the previous value of the sample sheet, and with the test value of the standard sheet obtained by the calibrated cd-sem stand as the previous value of the standard sheet:
OPALtarget＝QCtarget×OPALactual/QCactual
in the formula, OPALtargetIndicating the standard value of the standard plate, QCactualRepresenting the pre-value, QC, of the sample chiptargetIndicating the target value, OPAL, of the sample pieceactualPre-value representing standard plate;
the calibration module is also used for automatically calibrating the characteristic dimension scanning electron microscope machine again according to the standard value of the standard sheet;
the acquisition module is also used for acquiring a new test value of the sample slice by adopting the automatically calibrated characteristic dimension scanning electron microscope machine;
the judging module is further used for judging whether the difference value between the new test value of the sample piece and the target value of the sample piece is within a preset range, and if yes, the fact that the characteristic size scanning electron microscope machine calibration is completed is confirmed.
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