Drawing device

Abstract

A drawing apparatus capable of reducing the influence of contamination is provided. [Solution] A drawing device that draws a pattern on a sample by irradiating it with a charged particle beam, includes a mark, a deflector that deflects the charged particle beam, a detector that detects secondary charged particles emitted from the sample by irradiating the sample with the charged particle beam, and a control unit that controls the scanning position of the mark to be scanned with the charged particle beam, and the control unit performs a process of determining whether or not there is an effect of contamination based on a signal obtained by detecting the secondary charged particles with the detector while scanning the mark with the charged particle beam, and a process of changing the scanning position of the mark if it is determined that there is an effect of contamination.

Description

[Technical Field]

[0001] The present invention relates to a drawing device. [Background technology]

[0002] Electron beam lithography systems are known that irradiate a material with an electron beam to draw a pattern. In such systems, the pattern is accurately drawn at a desired position on the material using the position of an alignment mark provided on the sample stage as a reference.

[0003] For example, Patent Document 1 discloses a mark position detection method in which an autocorrelation calculation is performed on a backscattered electron signal obtained by scanning an alignment mark with an electron beam, using an approximate value of the width of the signal component obtained from the alignment mark as a period, and the mark position is determined based on the result of the autocorrelation calculation. In this way, by performing an autocorrelation calculation on the backscattered electron signal, the noise level can be sufficiently reduced and the mark position can be accurately detected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-302741 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to accurately detect the position of the mark, it is necessary to reduce the influence of contamination caused by carbon and other particles that adhere to the material when irradiated with the electron beam. [Means for solving the problem]

[0006] One aspect of the drawing device according to the present invention is A drawing apparatus that draws a pattern on a sample by irradiating the sample with a charged particle beam, Mark and a deflector that deflects the charged particle beam; a detector that detects secondary charged particles emitted from the sample by irradiating the sample with a charged particle beam; a control unit that controls a scanning position at which the mark is scanned with a charged particle beam; Including, The control unit a process of determining whether or not there is an influence of contamination based on a signal obtained by detecting secondary charged particles with the detector while scanning the mark with a charged particle beam; a process of changing the scanning position of the mark when it is determined that there is an influence of contamination; Do the following.

[0007] In such a drawing apparatus, the scanning position of the mark is changed when it is determined that there is an influence of contamination, so that the influence of contamination can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the arrangement of a rendering device according to a first embodiment. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a diagram showing an example of the configuration of a control device. [Figure 5] 10 is a flowchart showing an example of alignment processing by the control device. [Figure 6] 5A to 5C are diagrams for explaining each step of the alignment process. [Figure 7] 5A to 5C are diagrams for explaining each step of the alignment process. [Figure 8] 5A to 5C are diagrams for explaining each step of the alignment process. [Figure 9] 5A to 5C are diagrams for explaining each step of the alignment process. [Figure 10] 10 is a flowchart showing an example of a scanning position change process of the control device. [Figure 11]5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 12] 5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 13] 5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 14] 5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 15] 10 is a graph showing the change over time of the maximum value of the autocorrelation signal and a graph showing the change over time of the minimum value of the autocorrelation signal. [Figure 16] 10 is a flowchart showing an example of a scanning position change process of the control device. [Figure 17] 5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 18] 5A to 5C are diagrams for explaining each step of the scanning position change process. [Figure 19] FIG. 11 is a plan view schematically showing a plurality of marks of the drawing device according to the third embodiment. [Figure 20] 10 is a flowchart showing an example of a scanning position change process of the control device. [Figure 21] FIG. [Figure 22] 10 is a flowchart showing an example of a scanning position change process of the control device. [Figure 23] FIG. 13 is a diagram showing an example of the arrangement of a rendering apparatus according to a fifth embodiment. [Figure 24] FIG. [Figure 25] FIG. 4 is a diagram for explaining how an absorption current signal is obtained. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0010] 1. First embodiment 1.1. Drawing device 1.1.1. Drawing device configuration First, a drawing device according to the first embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a drawing device 100 according to the first embodiment. Note that Fig. 1 illustrates an X-axis, a Y-axis, and a Z-axis as three mutually orthogonal axes.

[0011] The lithography apparatus 100 is an electron beam lithography apparatus that irradiates an electron beam to draw a pattern on a sample 2. The sample 2 is, for example, a lithography material such as a semiconductor substrate or a mask blank. The lithography apparatus 100 draws a fine pattern such as a semiconductor integrated circuit pattern on the sample 2, such as a semiconductor substrate or a mask blank. Note that, although a case will be described in which the lithography apparatus 100 irradiates an electron beam to draw a pattern on the sample, a charged particle beam other than an electron beam, such as an ion beam, may also be used to draw a pattern on the sample 2.

[0012] 1, the drawing apparatus 100 includes an electron gun 10, an electron optical system 20, a stage 30, a detector 40, a mark 50, a substrate 60, and a control device 70 (an example of a control unit). The drawing apparatus 100 further includes a deflector driving circuit 72, an A / D converter 74, a signal processing unit 76, and a stage driving circuit 78.

[0013] The electron gun 10 generates an electron beam and emits the generated electron beam. The electron beam emitted from the electron optics 20 travels along the optical axis of the electron optics 20, which is parallel to the Z axis.

[0014] The electron optical system 20 irradiates the sample 2 with the electron beam emitted from the electron gun 10. The electron optical system 20 includes a blanker 22 that blanks the electron beam, a focusing lens 24 that focuses the electron beam, an objective lens 26, and a deflector 28. The deflector 28 deflects the electron beam emitted from the electron gun 10 and focused by the focusing lens 24. By deflecting the electron beam with the deflector 28, the sample 2 can be scanned with the electron beam. The deflector driving circuit 72 is a circuit for operating the deflector 28. Note that the drawing apparatus 100 may be a variable shaped beam type drawing apparatus that divides a drawing pattern into rectangles and draws the divided rectangular patterns with a rectangular electron beam of variable size.

[0015] The stage 30 supports the sample 2. The stage 30 is equipped with an X-movement mechanism that moves the sample 2 along the X-axis and a Y-movement mechanism that moves the sample 2 along the Y-axis. The sample 2 supported by the stage 30 is housed in a sample chamber that can be maintained in a vacuum state. The stage drive circuit 78 is a circuit for operating the stage 30.

[0016] The detector 40 is a backscattered electron detector that detects backscattered electrons emitted from the sample 2 when the sample 2 is irradiated with an electron beam. The detector 40 converts the detected backscattered electrons into an electric signal. The A / D converter 74 converts the input electric signal into a digital signal and outputs it to the signal processing unit 76 as a backscattered electron signal. The signal processing unit 76 performs various arithmetic processing on the backscattered electron signal and outputs the arithmetic results to the control device 70. The functions of the signal processing unit 76 may be realized, for example, by a general-purpose circuit such as a microcontroller or microprocessor that operates according to a program, or may be realized by a dedicated circuit such as an ASIC (application specific integrated circuit).

[0017] The marks 50 are provided on a substrate 60. The substrate 60 on which the marks 50 are provided is placed on a stage 30. The marks 50 are used for various corrections (calibrations) of the drawing apparatus 100. The marks 50 are used, for example, as a reference for positioning when drawing a pattern.

[0018] The control device 70 controls each component of the imaging apparatus 100. The control device 70 controls the deflector 28 via a deflector driving circuit 72. The control device 70 also controls the stage 30 via a stage driving circuit 78.

[0019] Mark Fig. 2 is a plan view that schematically shows the mark 50. Fig. 3 is a cross-sectional view that schematically shows the mark 50. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.

[0020] 2, the mark 50 has a cross shape in a plan view, that is, when viewed from the direction along the Z axis. The mark 50 has a first portion 51 extending in the +Y direction from a center O of the mark 50, a second portion 52 extending in the −Y direction from the center O, a third portion 53 extending in the +X direction from the center O, and a fourth portion 54 extending in the −X direction from the center O.

[0021] The width (size along the X-axis) of the first portion 51 and the width (size along the X-axis) of the second portion 52 are equal. The length (size along the Y-axis) of the first portion 51 and the length (size along the Y-axis) of the second portion 52 are equal. Similarly, the width (size along the Y-axis) of the third portion 53 and the width (size along the Y-axis) of the fourth portion 54 are equal. The length (size along the X-axis) of the third portion 53 and the length (size along the X-axis) of the fourth portion 54 are equal.

[0022] The shape of the mark 50 is not particularly limited as long as the position of the mark 50 can be detected. Alternatively, it may be, for example, an L-shape having a first portion 51 and a third portion 53 .

[0023] As shown in FIG. 3, the mark 50 is formed on a substrate 60. The material of the mark 50 is a heavy metal with a high reflected electron emission rate. Examples of the material of the mark 50 include tantalum and gold. The material of the substrate 60 is, for example, a substance with a lower reflected electron emission rate than the mark 50. Examples of the material of the substrate 60 include silicon. The reflected electron emission rate is the ratio of the number of electrons incident on the sample to the number of reflected electrons emitted from the sample, and the higher the reflected electron emission rate, the greater the number of reflected electrons emitted from the sample relative to the number of electrons incident on the sample.

[0024] 1.1.3. Control Unit FIG. 4 is a diagram showing an example of the configuration of the control device 70.

[0025] As shown in FIG. 4, the control device 70 includes a processing unit 700, an operation unit 710, a display unit 720, and a storage unit 730.

[0026] The operation unit 710 is used by the user to input operation information, and outputs the input operation information to the processing unit 700. The functions of the operation unit 710 can be realized by input devices such as a keyboard, a mouse, buttons, a touch panel, or a touch pad.

[0027] The display unit 720 displays the image generated by the processing unit 700. The function of the display unit 720 can be realized by an LCD (Liquid Crystal Display), a touch panel display, or the like.

[0028] The storage unit 730 stores programs, data, etc. for the processing unit 700 to perform various calculation processes and various control processes. The storage unit 730 is also used as a working area for the processing unit 700, and is also used to temporarily store the results of calculations executed by the processing unit 700 in accordance with the various programs. The functions of the storage unit 730 can be realized by a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, etc.

[0029] The functions of the processing unit 700 can be realized by various processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a DSP (Digital Signal Processor) by executing programs stored in a storage unit 730. The processing unit 700 includes an optical system control unit 701, a stage control unit 702, a mark position detection unit 703, a determination unit 704, and a scanning position change unit 705.

[0030] An optical system control unit 701 controls the electron optical system 20. A stage control unit 702 controls the stage 30. A mark position detection unit 703 detects the position of the mark 50 based on a signal obtained by scanning the mark 50. A determination unit 704 determines whether or not there is an influence of contamination based on a reflected electron signal obtained by scanning the mark 50. If the determination unit 704 determines that there is an influence of contamination, a scan position change unit 705 performs processing to change the scan position. Details of the processing by the processing unit 700 will be described later.

[0031] 1.2. Control Device Processing 1.2.1. Alignment process The following describes the alignment process of the control device 70. The alignment process is a process of detecting the position of the mark 50 and correcting the position of the electron beam based on the detected position of the mark 50.

[0032] Fig. 5 is a flowchart showing an example of the alignment process of the control device 70. Figs. 6 to 9 are diagrams for explaining each step of the alignment process.

[0033] 6, the stage control unit 702 causes the stage 30 to move the mark 50 to a position immediately below the optical axis of the electron optical system 20 (step S10). The stage control unit 702 sends a movement instruction to the stage drive circuit 78 to move the mark 50 to a position immediately below the optical axis of the electron optical system 20. In response to the movement instruction, the stage drive circuit 78 operates the stage 30 so that the mark 50 moves to a position immediately below the optical axis of the electron optical system 20. As a result, the mark 50 is positioned immediately below the optical axis of the electron optical system 20.

[0034] Next, as shown in FIG. 7, the optical system control unit 701 causes the deflector 28 to deflect the electron beam so that the first portion 51 of the mark 50 is scanned with the electron beam (step S20).

[0035] The optical system control unit 701 reads out the information on the scanning position SX stored in the storage unit 730, and acquires the information on the scanning position SX of the first portion 51. The scanning position SX is set to an initial position in advance, and is changed when it is determined that the influence of contamination is large in the scanning position change process described later.

[0036] Here, the coordinates of the scanning position are expressed with the center O of the mark 50 as the origin, with the +X direction as positive, the -X direction as negative, the +Y direction as positive, and the -Y direction as negative. For example, the storage unit 730 stores the coordinates of the scanning position as information on the scanning position SX.

[0037] The optical system control unit 701 sends a scan instruction to the deflector driving circuit 72 to scan the scan position SX. In response to the scan instruction, the deflector driving circuit 72 operates the deflector 28 so that the scan position SX is scanned. As a result, the scan position SX of the first portion 51 of the mark 50 is scanned with the electron beam. Scanning of the scan position SX is performed by moving the electron beam along the X axis so as to cross the scan position SX of the first portion 51. The scanning range of the scan position SX is, for example, from a position on the substrate 60 located in the +X direction of the first portion 51, through the first portion 51, to a position on the substrate 60 located in the -X direction of the first portion 51. The memory unit 730 stores information on the scan range as well as information on the scan position.

[0038] The detector 40 detects reflected electrons emitted from the mark 50 by irradiating the mark 50 with an electron beam. The detector 40 converts the detected reflected electrons into an electrical signal and outputs it to the A / D converter 74. The A / D converter 74 converts the input electrical signal into a digital signal and outputs it to the signal processing unit 76 as a reflected electron signal.

[0039] Fig. 8 is a diagram for explaining the processing of the signal processing unit 76. Fig. 8 shows an example of a backscattered electron signal A, an example of a differential signal Ad obtained by first differentiating the backscattered electron signal A, and an example of an autocorrelation signal Z obtained by performing an autocorrelation calculation on the differential signal Ad. The horizontal axis of the graph of the backscattered electron signal A shown in Fig. 8 represents the X coordinate, and the vertical axis represents the signal intensity.

[0040] As shown in FIG. 8, the reflected electron emissivity of the mark 50 is greater than that of the substrate 60. Therefore, the reflected electron signal A has a convex shape. The differential signal Ad shown in FIG. 8 has a peak with a maximum value at a position corresponding to the rising edge of the reflected electron signal A and a peak with a minimum value at a position corresponding to the falling edge of the reflected electron signal A. These two peak positions correspond to the +X-direction edge and the −X-direction edge of the first portion 51 of the mark 50. In other words, the distance between the two peaks of the differential signal Ad corresponds to the width of the first portion 51 of the mark 50.

[0041] The autocorrelation calculation for the differential signal Ad is performed with a period equal to the width of the signal component generated from the mark 50. In the autocorrelation signal Z resulting from this autocorrelation calculation, signals with a period shorter than the width of the mark 50 are removed or sufficiently attenuated. In the autocorrelation signal Z, the distance between two peaks that take the maximum value corresponds to the width of the mark 50, and the position of the peak that takes the minimum value corresponds to the width of the mark 50. The position corresponds to the position of the center O of the mark 50. Such an autocorrelation calculation is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-302741.

[0042] The mark position detection unit 703 acquires the autocorrelation signal Z from the signal processing unit 76 (step S30) and identifies the X coordinate of the center O of the mark 50 from the autocorrelation signal Z (step S40). The mark position detection unit 703 identifies the position of the center O of the mark 50 based on the autocorrelation signal Z. Specifically, the mark position detection unit 703 finds the position where the autocorrelation signal Z takes the minimum value. This makes it possible to identify the X coordinate of the center O of the mark 50. By identifying the position of the mark 50 from the autocorrelation signal Z, the influence of noise can be reduced and the position of the mark 50 can be accurately detected in a short time.

[0043] By the above process, the X coordinate of the center O of the mark 50 can be identified.

[0044] Next, the Y coordinate of the center O of the mark 50 is identified. As shown in Fig. 9, the optical system control unit 701 causes the deflector 28 to deflect the electron beam so that the scanning position SY of the third portion 53 of the mark 50 is scanned with the electron beam (step S50).

[0045] The optical system control unit 701 reads out the information on the scanning position SY stored in the storage unit 730 and acquires the information on the scanning position SY of the third portion 53. The scanning position SY is set to an initial position in advance, and is changed when it is determined that the influence of contamination is large in the scanning position change process described below.

[0046] The optical system control unit 701 sends a scan instruction to the deflector driving circuit 72 to scan the scan position SY. In response to the scan instruction, the deflector driving circuit 72 operates the deflector 28 so that the scan position SY is scanned. As a result, the scan position SY of the third portion 53 of the mark 50 is scanned with the electron beam. By scanning the scan position SY, the detector 40 converts the detected reflected electrons into an electric signal, and the A / D converter 74 converts the electric signal into a digital signal and outputs it to the signal processing unit 76 as a reflected electron signal. The signal processing unit 76 first differentiates the reflected electron signal to generate a differential signal, performs an autocorrelation operation on the differential signal, and outputs an autocorrelation signal.

[0047] Next, the mark position detection unit 703 acquires the autocorrelation signal from the signal processing unit 76 (step S60), and identifies the Y coordinate of the center O of the mark 50 from the autocorrelation signal (step S70). The process S70 for identifying the Y coordinate of the center O is the same as the process S40 for identifying the X coordinate of the center O, and therefore a description thereof will be omitted.

[0048] The above processing makes it possible to detect the position of the mark 50. That is, the above processing makes it possible to identify the coordinates (X, Y) of the center O of the mark 50.

[0049] Next, the optical system control unit 701 corrects the position of the electron beam (writing position) based on the detected position of the mark 50 (step S80). For example, the optical system control unit 701 calculates the difference between the position of the mark 50 detected in the current alignment process and the position of the mark 50 detected in the previous alignment process as the positional deviation amount of the electron beam. The optical system control unit 701 corrects the electron beam based on the calculated positional deviation amount. The correction of the electron beam position is performed by applying a value (-ΔX, -ΔY) obtained by inverting the sign of the measured positional deviation amount (ΔX, ΔY) to the deflector 28. After correcting the position of the electron beam, the processing unit 700 ends the alignment process.

[0050] 1.2.2. Scanning position change processing When the same scanning position is repeatedly scanned with an electron beam, carbon and other contaminants accumulate on the scanning position due to the irradiation of the electron beam. This contamination causes the backscattered electron signal The waveform of A becomes dull, the difference between the maximum and minimum values ​​of the autocorrelation signal Z becomes small, and the position of the center O of the mark 50 may not be detected accurately.

[0051] The waveform of the backscattered electron signal A is due to the difference between the backscattered electron emissivity of the substrate 60 and that of the mark 50. Here, if contaminants such as carbon accumulate to cover the substrate 60 and the mark 50 through repeated scanning of the electron beam, the amount of backscattered electrons emitted from the contaminants increases. As a result, the backscattered electrons emitted from the contaminants become dominant in the backscattered electron signal A, and the waveform of the backscattered electron signal A becomes dull. Therefore, the difference between the maximum and minimum values ​​of the differential signal Ad becomes smaller, and the difference between the maximum and minimum values ​​of the autocorrelation signal Z also becomes smaller.

[0052] Therefore, in order to reduce the influence of contamination, the drawing device 100 performs a process of determining whether or not there is an influence of contamination based on a signal obtained by detecting reflected electrons with the detector 40 while scanning the mark 50 with an electron beam, and a process of changing the scanning position of the mark 50 if it is determined that there is an influence of contamination.

[0053] Fig. 10 is a flowchart showing an example of the scanning position change processing of the control device 70. Figs. 11 to 14 are diagrams for explaining each step of the scanning position change processing.

[0054] When an instruction to start the scanning position change process is input to the processing unit 700, the stage control unit 702 causes the stage 30 to move the mark 50 to directly below the optical axis of the electron optical system 20, as shown in FIG. 6 (step S100).

[0055] Next, the optical system control unit 701 causes the deflector 28 to deflect the electron beam so that the mark 50 is scanned with the electron beam (step S102).

[0056] The scanning position is set to the scanning position stored in the storage unit 730. For example, the storage unit 730 stores in advance the scanning position SX-1 of the first portion 51, which is the initial position. When the scanning position is updated in the scanning position change process, the updated scanning position is stored in the storage unit 730.

[0057] Here, a case will be described where scanning position SX-1 is stored in storage unit 730. Scanning position SX-1, which is the initial position, is a position that is a distance D1 away in the +Y direction from the center O of mark 50. Process S102 is performed in the same manner as process S20 shown in FIG.

[0058] 11, by executing process S102, the scanning position SX-1 of the first portion 51 of the mark 50 is scanned with the electron beam. As a result, the electrical signal output from the detector 40 is converted into a digital signal by the A / D converter 74 and output as a reflected electron signal to the signal processing unit 76. The signal processing unit 76 performs first-order differentiation of the reflected electron signal to generate a differential signal, performs autocorrelation calculation on the differential signal, and outputs an autocorrelation signal.

[0059] The decision unit 704 acquires the autocorrelation signal output from the signal processing unit 76 (step S104), and calculates the difference between the maximum and minimum values ​​of the autocorrelation signal (step S106).

[0060] 12, the determination unit 704 detects the maximum and minimum values ​​of the autocorrelation signal obtained at the scanning position SX-1, calculates the difference between the maximum and minimum values, and determines whether the difference between the maximum and minimum values ​​of the autocorrelation signal is greater than a threshold value (step S108).

[0061] The determining unit 704 determines that there is no influence of contamination when the difference between the maximum and minimum values ​​of the autocorrelation signal is greater than the threshold. If it is not large, it is determined that there is an influence of contamination.

[0062] The threshold value used as the basis for judgment can be set appropriately depending on the required detection accuracy of the mark 50. For example, the difference between the maximum and minimum values ​​of the autocorrelation signal obtained by scanning with the electron beam a mark 50 that has never been scanned with the electron beam may be calculated, and a value that is about 50% of this difference may be used as the threshold value.

[0063] When the determination unit 704 determines that the difference is not greater than the threshold value (No in step S108), the scanning position changing unit 705 changes the scanning position from the scanning position SX-1 to the scanning position SX-2 (step S110).

[0064] As shown in FIG. 13, the scanning position changing unit 705 adds a preset distance a to the distance D1 between the scanning position SX-1 and the center O. That is, the scanning position changing unit 705 adds a to the Y coordinate of the scanning position SX-1. Thereby, the scanning position is changed from the scanning position SX-1 to the scanning position SX-2. That is, the distance D2 between the scanning position SX-2 and the center O is A + a. The scanning position changing unit 705 updates the scanning position stored in the storage unit 730 from the scanning position SX-1 to SX-2.

[0065] Next, the scanning position changing unit 705 counts the number N of times the process of changing the scanning position is repeated (step S112), and determines whether the number of repetitions N is less than the threshold value T (step S114).

[0066] If the process S110 of changing the scanning position is repeated and it is determined that there is an influence of contamination at all the scanning positions of the first portion 51, the scanning position will be located outside the mark 50. Therefore, the number of repetitions N is limited so that the scanning position is not located outside the mark 50.

[0067] Specifically, as shown in FIG. 13, the distance between the center O of the mark 50 and the tip in the +Y direction of the first portion 51 is L, that is, the length of the first portion 51 is L, the distance added when the scanning position is changed is a, and the number of repetitions is N. When L < D1 + a×N is satisfied, the scanning position is located outside the mark 50. Therefore, the minimum value of N that satisfies L < D1 + a×N is set as the threshold value T. That is, when the number of repetitions N is less than the threshold value T, the scanning position is located within the mark 50, and when the number of repetitions N is greater than or equal to the threshold value T, the scanning position is located outside the mark 50.

[0068] When the scanning position changing unit 705 determines that N < T is satisfied (Yes in step S114), it returns to step S102, and the optical system control unit 701 deflects the electron beam so that the first portion 51 of the mark 50 is scanned by the electron beam on the deflector 28 (step S102). Since the scanning position SX-2 is stored in the storage unit 730, the optical system control unit 701 deflects the electron beam so that the scanning position SX-2 of the first portion 51 is scanned by the electron beam on the deflector 28.

[0069] The determination unit 704 acquires the autocorrelation signal output from the signal processing unit 76 (step S104), and calculates the difference between the maximum value and the minimum value of the autocorrelation signal (step S106). The determination unit 704 determines whether the difference between the maximum value and the minimum value of the autocorrelation signal is greater than the threshold value (step S108). When the determination unit 704 determines that the difference is not greater than the threshold value (No in step S108), the scanning position changing unit 705 changes the scanning position from the scanning position SX-2 to the scanning position SX-3 (step S110). The scanning position changing unit 705 counts the number of repetitions N, and determines whether the number of repetitions N is less than the threshold value T (step S114).

[0070] In this way, the processing unit 700 repeats the processing from step S102 to step S114 until it is determined that the difference between the maximum value and the minimum value of the autocorrelation signal is greater than the threshold value, that is, until it is determined that there is no influence of contamination, or until it is determined that N < T is not satisfied. Therefore, every time it is determined that the difference is not greater than the threshold value, as shown in FIG. 14, the scanning position becomes larger by a distance a from the center O. That is, every time it is determined that the difference is not greater than the threshold value, a is added to the Y coordinate of the scanning position. In the example shown in FIG. 14, the scanning position is first changed from the scanning position SX-1 at a distance D1 from the center O to the scanning position SX-2 at a distance D1 + a from the center O. Next, the scanning position is changed from the scanning position SX-2 to the scanning position SX-3 at a distance D1 + 2×a from the center O.

[0071] When the determination unit 704 determines that the difference between the maximum value and the minimum value of the autocorrelation signal is greater than the threshold value, that is, when it is determined that there is no influence of contamination (Yes in step S108), the processing unit 700 ends the scanning position change process. As a result, information on the scanning position without the influence of contamination is stored in the storage unit 730.

[0072] Also, when the scanning position change unit 705 determines that N<T is not satisfied, that is, when the scanning position is located outside the mark 50 (No in step S114), the scanning position change unit 705 generates abnormal information indicating that the scanning position is located outside the mark 50 (step S116).

[0073] Here, in the first portion 51, when the process of changing the scanning position is repeated and it is determined that there is an influence of contamination at all the scanning positions in the first portion 51, N<T is not satisfied. Therefore, the scanning position change unit 705 generates abnormal information. That is, the abnormal information can also be said to be information indicating that dirt has accumulated throughout the first portion 51 and there is no scanning position in the first portion 51 that is not affected by contamination.

[0074] The scanning position change unit 705 stores the generated abnormal information in the storage unit 730. The scanning position change unit 705 may display the abnormal information on the display unit 720 to notify the user that the scanning position is located outside the mark 50. After storing the abnormal information in the storage unit 730, the processing unit 700 ends the scanning position change process. In this case, the abnormal information is stored in the storage unit 730 together with the scanning position information.

[0075] In the above description, the process of changing the scanning position of the first portion 51 of the mark 50 has been described. However, the process of changing the scanning position of the third portion 53 of the mark 50 is the same, and the description thereof is omitted. After the process of changing the scanning position of the first portion 51 of the mark 50 described above, the process of changing the scanning position of the third portion 53 of the mark 50 may be performed.

[0076] In the scanning position change process shown in Fig. 10 described above, a scanning position that is not affected by contamination is stored in the storage unit 730. In process S20 shown in Fig. 5 in which the deflector 28 is caused to scan the scanning position SX, the scanning position stored in the storage unit 730 is read out and set as the scanning position, so that the effect of contamination can be reduced by executing the scanning position change process. Furthermore, if abnormality information is stored in the storage unit 730, for example, the alignment process shown in Fig. 5 may be interrupted.

[0077] 1.2.3. Effect of scanning position change processing Figure 15 shows the graph G showing the time course of the maximum value of the autocorrelation signal. Max , and graph G showing the time evolution of the minimum of the autocorrelation signal. Min Graph G Max The horizontal axis of Graph G is the number of days, and the vertical axis is the maximum value of the autocorrelation signal. Min The horizontal axis of Graph G is the number of days, and the vertical axis is the minimum value of the autocorrelation signal. Max When the X coordinate of mark 50 is specified, The maximum value (X) of the autocorrelation signal used to identify the Y coordinate of the mark 50 is plotted in the graph G. Min , the maximum value (X) of the autocorrelation signal used to identify the X coordinate of the mark 50 and the maximum value (Y) of the autocorrelation signal used to identify the Y coordinate of the mark 50 are plotted.

[0078] Scans were performed at the same scanning position from day 0 to day 21. Due to the effects of contamination, the maximum value of the autocorrelation signal decreased and the minimum value of the autocorrelation signal increased as the days passed. Therefore, on day 21, the difference between the maximum and minimum values ​​of the autocorrelation signal was at its smallest.

[0079] The scanning position was changed on day 22. As a result, the maximum value of the autocorrelation signal increased and the minimum value of the autocorrelation signal decreased on day 22 compared to day 21. Therefore, the difference between the maximum and minimum values ​​of the autocorrelation signal was larger on day 22 compared to day 21.

[0080] In this way, by changing the scanning position, the difference between the maximum and minimum values ​​of the autocorrelation signal can be increased, and the influence of contamination can be reduced.

[0081] Effects The writing apparatus 100 includes a mark 50, a deflector 28 that deflects the electron beam, a detector 40 that detects reflected electrons emitted from the sample 2 when the sample 2 is irradiated with the electron beam, and a control device 70 as a control unit that controls the scanning position of the mark 50 scanned with the electron beam. The control device 70 performs a process of determining whether or not there is an effect of contamination based on a signal obtained by detecting the reflected electrons with the detector 40 while scanning the mark 50 with the electron beam, and a process of changing the scanning position of the mark 50 when it is determined that there is an effect of contamination.

[0082] Therefore, in the drawing apparatus 100, when it is determined that there is an influence of contamination, the scanning position of the mark 50 is changed, thereby reducing the influence of contamination and enabling the position of the mark 50 to be detected with high accuracy. Also, in the drawing apparatus 100, the control device 70 automatically changes the scanning position, enabling the mark 50 to be easily detected with high accuracy. Therefore, in the drawing apparatus 100, the position of the electron beam can be accurately corrected in the alignment process.

[0083] In the lithography system 100, the control device 70 determines whether there is an effect of contamination based on the waveform of the backscattered electron signal. Specifically, the control device 70 determines a change in the waveform of the backscattered electron signal due to the effect of contamination from the difference between the maximum and minimum values ​​of the autocorrelation signal. Therefore, the lithography system 100 can easily determine whether there is an effect of contamination.

[0084] 1.5. Variations 1.5.1. First variant In the above-described scanning position change process, the number of repetitions N is counted in step S112, and if the number of repetitions N is not smaller than the threshold value T in step S114, it is determined that the scanning position is located outside the mark 50 and abnormality information is generated, but the method of determining whether the scanning position is located outside the mark 50 is not limited to this.

[0085] For example, it may be possible to determine whether the scanning position is located outside the mark 50 by setting an upper limit value of the distance D between the scanning position and the center O. For example, it is possible to determine whether the scanning position is located outside the mark 50 by setting the upper limit value of the distance D between the scanning position and the center O to the length L of the first portion 51 shown in FIG.

[0086] Specifically, in the process of step S112, the scanning position changing unit 705 calculates the distance D between the scanning position and the center O, and determines in step S114 whether the distance D is smaller than the length L. If the scanning position changing unit 705 determines that the distance D is smaller than the length L (Yes in step S114), the process returns to step S102. On the other hand, if the scanning position changing unit 705 determines that the distance D is not smaller than the length L (No in step S114), the process generates anomaly information (step S116).

[0087] In the above, whether the scanning position is located outside the mark 50 is determined based on whether the distance D is smaller than the length L of the first part 51. However, whether the scanning position is located outside the mark 50 may also be determined based on whether the Y coordinate of the scanning position is smaller than the Y coordinate of the tip of the first part 51 of the mark 50.

[0088] In addition, in the scanning position change process, it is also possible to perform both a process of determining whether the scanning position is located outside the mark 50 based on whether the number of repetitions N is less than the threshold value T, and a process of determining whether the scanning position is located outside the mark 50 based on whether the distance D between the scanning position and the center O is less than the upper limit value.

[0089] 1.5.2. Second modification example As the distance D between the center O of the mark 50 and the scanning position increases, the accuracy of detecting the position of the center O of the mark 50 may deteriorate under the influence of the mounting error of the mark 50. For example, when the mark 50 is mounted inclined with respect to the substrate 60, that is, when the extending direction of the first portion 51 is inclined with respect to the Y-axis, the detection error of the position of the center O increases as the distance D between the center O and the scanning position increases.

[0090] Therefore, even when the scanning position is within the mark 50, a threshold value may be set so that abnormal information is generated when the distance D between the center O and the scanning position becomes equal to or greater than the upper limit value.

[0091] For example, the upper limit value of the distance D between the scanning position and the center O described in the first modification example may be set to the upper limit value distance D0 (D0 < L) within the range where the influence of the mounting error of the mark 50 can be tolerated. Specifically, in the process of step S112, the scanning position change unit 705 calculates the distance D between the scanning position and the center O, and in step S114, determines whether the distance D is less than the distance D0.

[0092] When the scanning position change unit 705 determines that the distance D is less than the distance D0 (Yes in step S114), it returns to step S102. On the other hand, when the scanning position change unit 705 determines that the distance D is not less than the distance D0 (No in step S114), it generates abnormal information (step S116). Thereby, for example, when the scanning position is outside the range where the influence of the mounting error of the mark 50 can be tolerated, an abnormality can be notified.

[0093] In addition, in the scanning position change process, both a process of determining whether the scanning position is located outside the mark 50 based on whether the number of repetitions N is smaller than a threshold value T, and a process of determining whether the scanning position is in a range where the influence of the attachment error of the mark 50 is large based on whether the distance D between the scanning position and the center O is smaller than an upper limit value may be performed.

[0094] 2. Second embodiment 2.1. Drawing device Next, a description will be given of a drawing device according to a second embodiment. The configuration of the drawing device according to the second embodiment is the same as the configuration of the drawing device 100 according to the first embodiment shown in Fig. 1, and therefore a description thereof will be omitted.

[0095] 2.2. Scanning position change processing In the first embodiment described above, the scanning position is repeatedly changed in the first portion 51 of the mark 50, and when it is determined that there is an effect of contamination at all scanning positions in the first portion 51, anomaly information is generated and the scanning position change process is terminated. In contrast, in the second embodiment, when it is determined that there is an effect of contamination at all scanning positions in the first portion 51, the scanning position is changed from the first portion 51 to the second portion 52.

[0096] Fig. 16 is a flowchart showing an example of the scanning position change processing of the control device 70. Fig. 17 and Fig. 18 are diagrams for explaining each step of the scanning position change processing.

[0097] When an instruction to start the scanning position change process is input to the processing unit 700, the stage control unit 702 causes the stage 30 to move the mark 50 to directly below the optical axis of the electron optical system 20, as shown in FIG. 6 (step S200).

[0098] Next, the optical system control unit 701 causes the deflector 28 to deflect the electron beam so that the mark 50 is scanned with the electron beam (step S202). The scanning position is set to the scanning position stored in the storage unit 730.

[0099] The processes of step S202 to step S214 are the same as the processes of step S102 to step S114 shown in FIG. 10 described above. Therefore, the description of the processes of step S202 to step S214 is omitted.

[0100] When the scanning position changing unit 705 determines that N<T is not satisfied, that is, when the scanning position is located outside the mark 50 (No in step S214), it determines whether the sign of the Y coordinate of the scanning position is negative (step S216). When the scanning position changing unit 705 determines that the sign of the Y coordinate of the scanning position is not negative, that is, when the scanning position is the first part 51 (No in step S216), it changes the scanning position from the first part 51 to the second part 52 (step S218).

[0101] As shown in FIG. 17, the scanning position changing unit 705 changes the scanning position to the initial position of the scanning position in the second part 52, which is the scanning position SX-1(-). Here, the Y coordinate of the scanning position SX-1 is positive, and the Y coordinate of the scanning position SX-1(-) is negative. The scanning position SX-1(-) of the second part 52 is a position that is separated from the center O of the mark 50 by a distance D1 in the -Y direction. The scanning position changing unit 705 updates the scanning position stored in the storage unit 730 to the scanning position SX-1(-) of the second part 52.

[0102] After the scanning position changing unit 705 changes the scanning position from the first part 51 to the second part 52 (after step S218), it returns to step S202, and the optical system control unit 701 deflects the electron beam so that the mark 50 is scanned by the electron beam on the deflector 28 (step S202). Since the scanning position SX-1(-) of the second part 52 is stored in the storage unit 730, the optical system control unit 701 deflects the electron beam so that the scanning position SX-1(-) of the second part 52 is scanned by the electron beam on the deflector 28.

[0103] The processing unit 700 repeats the processing from step S202 to step S214 until it is determined that the difference between the maximum value and the minimum value of the autocorrelation signal is greater than the threshold value, or until it is determined that N<T is not satisfied. Therefore, every time it is determined that the difference is not greater than the threshold value, as shown in FIG. 18, the scanning position increases by a in the distance from the center O. That is, every time it is determined that the difference is not greater than the threshold value, -a is added to the Y coordinate of the scanning position. In the example shown in FIG. 18, the scanning position first changes from the scanning position SX-1(-) whose distance from the center O is D1 to the scanning position SX-2(-) whose distance from the center O is D1 + a is changed to. Next, the scanning position is changed from the scanning position SX-2(-) to the scanning position SX-3(-) whose distance from the center O is D1 + 2×a

[0104] When the scanning position changing unit 705 determines that N<T is not satisfied (No in step S214), the scanning position changing unit 705 determines whether the sign of the Y coordinate of the scanning position is negative (step S216). When the scanning position changing unit 705 determines that the sign of the Y coordinate of the scanning position is negative (Yes in step S216), the scanning position changing unit 705 generates abnormal information indicating that the scanning position is located outside the mark 50 (step S220). The processing in step S220 is performed in the same manner as the processing in step S116 shown in FIG. 10 described above

[0105] When the determination unit 704 determines that the difference between the maximum value and the minimum value of the autocorrelation signal is greater than the threshold value (Yes in step S208), or after the scanning position changing unit 705 generates abnormal information (after step S220), the processing unit 700 ends the scanning position changing process

[0106] In the above, the process of changing the scanning position from the first part 51 to the second part 52 of the mark 50 has been described. However, the process of changing the scanning position from the third part 53 to the fourth part 54 of the mark 50 is the same, and the description thereof is omitted

[0107] 2.3. Effects In the writing device 100, the mark 50 has a first portion 51 extending from a center O of the mark 50 in a +Y direction (an example of a first direction) and a second portion 52 extending from the center O of the mark 50 in a −Y direction (an example of a second direction) opposite to the +Y direction. The control device 70 repeats a process of determining whether or not there is an influence of contamination based on a signal obtained by scanning the first portion 51, and a process of changing the scanning position in the first portion 51 when it is determined that there is an influence of contamination. Furthermore, the control device 70 changes the scanning position from the first portion 51 to the second portion 52 when it is determined that there is an influence of contamination at all scanning positions in the first portion 51.

[0108] Therefore, the drawing device 100 can perform alignment processing using not only the first portion 51 of the mark 50 but also the second portion 52. Therefore, the drawing device 100 can extend the life of the alignment mark 50.

[0109] In the imaging device 100, when the control device 70 determines that the number of times the process of changing the scanning position in the first portion 51 has been repeated is equal to or greater than a predetermined number N, the control device 70 changes the scanning position from the first portion 51 to the second portion 52. Therefore, in the imaging device 100, when there is an effect of contamination at all scanning positions in the first portion 51, the control device 70 can change the scanning position from the first portion 51 to the second portion 52.

[0110] 3. Third embodiment 3.1. Drawing device Next, a drawing device according to a third embodiment will be described. Fig. 19 is a plan view schematically showing a plurality of marks 50 of the drawing device 100 according to the third embodiment. The drawing device 100 according to the third embodiment has the same configuration as the drawing device 100 according to the first embodiment shown in Fig. 1, except that it has a plurality of marks 50. Therefore, the following will describe only the differences from the drawing device 100 according to the first embodiment, and will omit a description of the similarities.

[0111] 19, the drawing device 100 has a plurality of marks 50. In the example shown in Fig. 19, the drawing device 100 has a first mark 50A, a second mark 50B, a third mark 50C, and a fourth mark 50D. The first mark 50A, the second mark 50B, the third mark 50C, and the fourth mark 50D have the same shape.

[0112] The first mark 50A has a first portion 51A extending in the +Y direction from the center OA of the first mark 50A, a second portion 52A extending in the -Y direction from the center OA, a third portion 53A extending in the +X direction from the center OA, and a fourth portion 54A extending in the -X direction from the center OA. The second mark 50B has a first portion 51B extending in the +Y direction from the center OB of the mark 50, a second portion 52B extending in the -Y direction from the center OB, a third portion 53B extending in the +X direction from the center OB, and a fourth portion 54B extending in the -X direction from the center OB. The tip of the fourth portion 54A of the first mark 50A and the tip of the third portion 53B of the second mark 50B are in contact with each other.

[0113] The third mark 50C and the fourth mark 50D also have the same shape as the first mark 50A and the second mark 50B.

[0114] Although the above description has been given of a case where there are four marks 50, the number of marks 50 is not particularly limited as long as it is two or more.

[0115] 3.2. Scanning position change processing In the drawing device 100, the control device 70 repeats the process of changing the scanning position at the first mark 50A, and when it determines that all scanning positions at the first mark 50A are affected by contamination, it changes the scanning position from the first mark 50A to the second mark 50B.

[0116] FIG. 20 is a flowchart showing an example of the scanning position change process of the control device 70.

[0117] When an instruction to start the scanning position change process is input to the processing unit 700, as shown in FIG. 6, the stage control unit 702 moves the mark 50 directly below the optical axis of the electron optical system 20 to the stage 30 (step S300).

[0118] Next, the optical system control unit 701 deflects the electron beam so that the mark 50 is scanned with the electron beam on the deflector 28 (step S302). The scanning position is set to the scanning position stored in the storage unit 730.

[0119] The processes of step S302 to step S318 are the same as the processes of step S202 to step S218 shown in FIG. 16 described above. Therefore, the description of the processes of step S302 to step S318 is omitted.

[0120] By repeating the processes of step S302 to step S318 by the processing unit 700, the repetition count N becomes larger than the threshold value T. That is, it is determined that all the scanning positions of the first portion 51A of the first mark 50A are affected by contamination, and the scanning position is changed from the first portion 51A to the second portion 52A. Further, by repeating the processes of step S302 to step S318 by the processing unit 700, the repetition count N becomes larger than the threshold value T. That is, it is determined that all the scanning positions of the second portion 52A are affected by contamination.

[0121] After determining that N<T is not satisfied (No in step S314), when the scanning position change unit 705 determines that the Y coordinate of the scanning position is negative (Yes in step S316), it determines whether there is another mark that has not been scanned (step S320). Information on the mark 50 is stored in the storage unit 730 in advance. The scanning position change unit 705 determines whether there is another mark based on the information on the mark 50 stored in the storage unit 730. Here, information on the first mark 50A, the second mark 50B, the third mark 50C, and the fourth mark 50D is stored in the storage unit 730. The scanning position change unit 705 is the first mark In addition to 50A, there are other marks that have not been scanned, namely, second mark 50B, third mark 50C, and fourth mark 50D, and therefore it is determined that there are other marks.

[0122] If it is determined that another mark exists (Yes in step S320), the scanning position changing unit 705 changes the scanning position from the first mark 50A to the second mark 50B (step S322). The scanning position changing unit 705 changes the scanning position to the initial position of the first portion 51B of the second mark 50B. The scanning position changing unit 705 updates the scanning position stored in the storage unit 730 to the initial position of the first portion 51B of the second mark 50B.

[0123] After the scanning position changing unit 705 changes the scanning position from the first mark 50A to the second mark 50B (after step S322), the process returns to step S302, and the optical system control unit 701 causes the deflector 28 to deflect the electron beam so that the mark 50 is scanned with the electron beam (step S202). The scanning position is set to the initial position of the first portion 51B of the second mark 50B stored in the storage unit 730.

[0124] In this way, the processing unit 700 repeats the processes of steps S302 to S322 until it is determined that there are no other marks 50. If it is determined that there are no other marks (No in step S320), the scanning position changing unit 705 generates abnormality information indicating that there are no scannable marks (step S324). The scanning position changing unit 705 stores the generated abnormality information in the storage unit 730.

[0125] If the determination unit 704 determines that the difference between the maximum and minimum values ​​of the autocorrelation signal is greater than the threshold value (Yes in step S308), or after the scanning position change unit 705 generates abnormality information (after step S324), the processing unit 700 terminates the scanning position change process.

[0126] Note that, although the above describes the process of changing the scanning position of the mark 50 used to detect the X coordinate of the mark 50, the process of changing the scanning position of the mark 50 used to detect the Y coordinate of the mark 50 is similar, and therefore the description thereof will be omitted.

[0127] Effects The writing device 100 has a plurality of marks 50, and the control device 70 repeats the following steps: determining whether or not there is an influence of contamination based on a signal obtained by scanning a first mark 50A of the plurality of marks; and, if it is determined that there is an influence of contamination, changing the scanning position of the first mark 50A. Furthermore, if it is determined that there is an influence of contamination at all scanning positions of the first mark 50A, the control device 70 changes the scanning position from the first mark 50A to a second mark 50B of the plurality of marks.

[0128] Therefore, the drawing apparatus 100 can perform alignment processing using a plurality of marks 50. Therefore, the drawing apparatus 100 can extend the life of the alignment marks.

[0129] 4. Fourth embodiment 4.1. Drawing device Next, a description will be given of a drawing device according to a fourth embodiment. The configuration of the drawing device according to the fourth embodiment is the same as the configuration of the drawing device 100 according to the first embodiment shown in FIG. 1, and therefore a description thereof will be omitted.

[0130] 4.2. Scanning position change processing In the drawing device 100, a plurality of types of correction (calibration) are performed using the marks 50. For example, the writing apparatus 100 can measure the drift of the sample 2 by the alignment process shown in Fig. 5 and correct the positional deviation of the sample 2 due to the drift of the sample 2 (hereinafter also referred to as drift correction). Also, for example, the writing apparatus 100 can detect the position of the mark 50 and correct the amount of deflection of the electron beam by the deflector 28 (hereinafter also referred to as deflection amount correction).

[0131] FIG. 21 is a plan view schematically showing the mark 50. As shown in FIG.

[0132] In deflection amount correction, for example, correction is not performed frequently, but it is necessary to accurately detect the position (coordinates) of the mark 50. Therefore, the range for setting the scanning position is set to the first region 510 of the first portion 51. This reduces the influence of attachment errors of the mark 50, and enables the position of the mark 50 to be accurately detected.

[0133] On the other hand, in drift correction, the position of the mark 50 detected at predetermined time intervals is compared, so correction is performed frequently, but is not affected by installation errors of the mark 50. Therefore, in drift correction, the range for setting the scanning position is set to the second region 520 of the first portion 51, which is farther from the center O of the mark 50 than the first region 510. In this way, the drawing device 100 sets the range for setting the scanning position based on information on the type of correction.

[0134] FIG. 22 is a flowchart showing an example of the scanning position change process of the control device 70.

[0135] The user inputs information about the type of correction via the operation unit 710. For example, the user may input the information about the type of correction by operating a GUI (Graphical User Interface) displayed on the display unit 720 using the operation unit 710. After inputting the information about the type of correction, the user inputs an instruction to start the scanning position change process.

[0136] When an instruction to start the scanning position change process is input to the processing unit 700, the scanning position change unit 705 acquires the input information on the type of correction (step S400).The scanning position change unit 705 determines the range in which the scanning position is to be set based on the information on the type of correction (step S402).

[0137] Information on the type of correction and the scanning area are stored in advance in association with each other in the storage unit 730. For example, the storage unit 730 stores deflection amount correction as information on the type of correction, and stores the first area 510 in association with the deflection amount correction. Similarly, the storage unit 730 stores the second area 520 in association with drift correction.

[0138] The scanning position changing unit 705 reads out area information associated with the input correction type information from the storage unit 730 and determines the range in which the scanning position is to be set. For example, if the input correction type information is deflection amount correction, the scanning position changing unit 705 sets the range in which the scanning position is to be set to the first area 510. If the input correction type information is drift correction, the scanning position changing unit 705 sets the range in which the scanning position is to be set to the second area 520.

[0139] After setting the range in which the scanning position is to be set (after step S402), the scanning position changing unit 705 performs scanning position changing processing S404. In the scanning position changing processing S404, for example, the scanning position changing processing shown in FIG. 10 described above is performed.

[0140] The scanning position change unit 705 stores information on the scanning position for each type of correction in the storage unit 730. For example, the storage unit 730 stores the initial position of the scanning position for each type of correction. Furthermore, when the scanning position is changed by the scanning position change process S404, the scanning position information stored in the storage unit 730 is updated for each type of correction. Furthermore, in the process S114 for determining whether the number of repetitions N is smaller than a threshold value, a threshold value may be set for each type of correction. Furthermore, for example, in the process of step S114, a threshold value T is set so that abnormality information is generated when the scanning position is set outside the range in which the scanning position is set.

[0141] In the scanning position change process S404, the scanning position change process shown in FIG. 16 may be performed, or the scanning position change process shown in FIG. 20 may be performed.

[0142] Furthermore, the above describes the process of changing the scanning position of the mark 50 used to detect the X coordinate of the mark 50, but the process of changing the scanning position of the mark 50 used to detect the Y coordinate of the mark 50 is similar, and therefore the description thereof will be omitted.

[0143] Effects In the imaging device 100, the control device 70 receives information on the type of correction using the mark 50 and sets a range for setting the scanning position based on the information on the type of correction. Therefore, the imaging device 100 can extend the life of the mark 50.

[0144] In the writing device 100, the first portion 51 of the mark 50 has a first region 510 and a second region 520 that is located at a greater distance from the center O of the mark 50 than the first region 510. Furthermore, when the information on the type of correction is information on the first correction (deflection amount correction), the control device 70 sets the range for setting the scanning position to the first region 510, and when the information on the type of correction is information on the second correction (drift correction) that is different from the first correction, the control device 70 sets the range for setting the scanning position to the second region 520. Therefore, the writing device 100 can extend the life of the mark 50.

[0145] 5. Fifth embodiment Next, a drawing device according to a fifth embodiment will be described with reference to the drawings. Fig. 23 is a diagram showing an example of the configuration of a drawing device 100 according to the fifth embodiment. Hereinafter, in the drawing device 100 according to the fifth embodiment, components having the same functions as those of the drawing device 100 according to the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0146] As shown in FIG. 23, the drawing device 100 includes a mark 80, a detector 90, an A / D converter 75, and a signal processing unit 77.

[0147] The mark 80 is a knife edge used to measure the current, size, position, and blur of the electron beam of the electron beam. In the drawing apparatus 100, similar to the mark 50 described above, multiple types of correction (calibration) can be performed by scanning the mark 80 with the electron beam.

[0148] The detector 90 detects the electron beam. The detector 90 is, for example, a Faraday cup. The mark 80 and the detector 90 are provided on the stage 30, for example.

[0149] The detector 90 converts the detected electron beam into an electrical signal and outputs it to the A / D converter 75. The A / D converter 75 converts the input electrical signal into a digital signal and outputs it to the signal processing unit 77. The signal processing unit 77 receives the digital signal and generates an absorption current signal that indicates the relationship between the current amount of the electron beam and its position on the stage 30.

[0150] Fig. 24 is a plan view schematically showing the mark 80. Fig. 25 is a diagram for explaining how an absorption current signal is obtained.

[0151] As shown in Fig. 24, a rectangular opening 82 is formed in the mark 80. The detector 90 is disposed below the mark 80, i.e., in the -Z direction. As shown in Fig. 25, when the electron beam EB is scanned across the mark 80 in the -X direction so as to cross an edge 83 of the opening 82 of the mark 80 along the Y axis, the proportion of the electron beam EB passing through the opening 82 gradually increases from a state in which the electron beam EB is entirely blocked by the mark 80. Therefore, the amount of current detected by the detector 90 increases as the scanning of the electron beam EB progresses.

[0152] In this way, while the electron beam EB is scanning the edge 83 of the opening 82 of the mark 80, the detector 90 measures the amount of current of the electron beam that has passed through the opening 82, thereby obtaining an absorbed current signal.

[0153] Various correction processes can be performed from the absorbed current signal obtained in this way. For example, by detecting the rising position of the absorbed current signal, the X coordinate of the edge 83 can be identified. This allows drift correction. Furthermore, for example, the size and focus of the electron beam can be measured from the waveform of the absorbed current signal.

[0154] Here, if contaminants such as carbon accumulate on the edge 83 of the opening 82 of the mark 80 due to repeated scanning of the electron beam, the amount of reflected electrons emitted from the contaminants increases. As a result, the waveform of the absorbed current signal becomes dull. In this way, the absorbed current signal is also affected by contamination, just like the reflected electron signal.

[0155] Therefore, the imaging device 100 according to the fifth embodiment performs the scanning position change process shown in Fig. 10. The scanning position change process in the imaging device 100 according to the fifth embodiment is the same as the scanning position change process shown in Fig. 10 except that the mark 80 is used instead of the mark 50, the detector 90 is used instead of the detector 40, and the absorbed current signal is used instead of the reflected electron signal, and therefore a description thereof will be omitted.

[0156] 16 may be performed in the drawing device 100 according to the fifth embodiment. In this case, the first portion 51 of the mark 50 corresponds to an edge 83 of the opening 82 of the mark 80 in the +X direction, and the second portion 52 of the mark 50 corresponds to an edge 85 of the opening 82 of the mark 80 in the −X direction.

[0157] 6. Variations The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0158] 6.1. First Variant In the above-described first embodiment, as shown in FIG. 8 , the change in the waveform of the backscattered electron signal A due to the influence of contamination is evaluated based on the difference between the maximum and minimum values ​​of the autocorrelation signal Z. However, the method for evaluating the change in the waveform of the backscattered electron signal A due to the influence of contamination is not particularly limited.

[0159] For example, the influence of contamination may be evaluated based on the difference between the maximum and minimum values ​​of the differential signal Ad shown in FIG. 8. The influence of contamination may also be evaluated based on the maximum value of the autocorrelation signal Z. For example, when the maximum value of the autocorrelation signal Z is smaller than a threshold value, it may be determined that there is an influence of contamination. The influence of contamination may also be evaluated based on the minimum value of the autocorrelation signal Z. For example, when the minimum value of the autocorrelation signal Z is larger than a threshold value, it may be determined that there is an influence of contamination. stomach.

[0160] In this way, there are no particular limitations on the method of evaluating the waveform of the backscattered electron signal when determining whether or not there is an influence of contamination based on the waveform of the backscattered electron signal.

[0161] The same applies to the second to fourth embodiments. In the fifth embodiment, when determining whether or not there is an influence of contamination based on the waveform of the absorption current signal, a parameter of the focus information may be calculated from the absorption current signal or a differential signal obtained by first differentiating the absorption current signal, and if the value exceeds a threshold, it may be determined that there is an influence of contamination.

[0162] 6.2. Second Variant In the above-described first embodiment, an electron beam is irradiated onto the mark 50, and reflected electrons emitted from the mark 50 are detected. However, a charged particle beam such as an ion beam may be irradiated onto the mark 50, and secondary charged particles emitted from the mark 50 may be detected. Examples of secondary charged particles include secondary electrons, reflected electrons, and ions.

[0163] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0164] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially identical to the configurations described in the embodiments. A substantially identical configuration means, for example, a configuration with the same function, method, and result, or a configuration with the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0165] 2...sample, 10...electron gun, 20...electron optical system, 22...blanker, 24...focusing lens, 26...objective lens, 28...deflector, 30...stage, 40...detector, 50...mark, 50A...first mark, 50B...second mark, 50C...third mark, 50D...fourth mark, 51...first part, 51A...first part, 51B...first part, 52...second part, 52A...second part, 52B...second part, 53...third part, 53A...third part, 53B...third part, 54...fourth part, 54A...fourth part, 54B...fourth part, 6 0...substrate, 70...control device, 72...deflector drive circuit, 74...A / D converter, 75...A / D converter, 76...signal processing unit, 77...signal processing unit, 78...stage drive circuit, 80...mark, 82...opening, 83...edge, 85...edge, 90...detector, 100...drawing device, 510...first region, 520...second region, 700...processing unit, 701...optical system control unit, 702...stage control unit, 703...mark position detection unit, 704...determination unit, 705...scanning position change unit, 710...operation unit, 720...display unit, 730...storage unit

Claims

1. A drawing apparatus that draws a pattern on a sample by irradiating the sample with a charged particle beam, Mark and a deflector that deflects the charged particle beam; a detector that detects secondary charged particles emitted from the sample by irradiating the sample with a charged particle beam; a control unit that controls a scanning position at which the mark is scanned with a charged particle beam; Including, The control unit a process of determining whether or not there is an influence of contamination based on a signal obtained by detecting secondary charged particles with the detector while scanning the mark with a charged particle beam; a process of changing the scanning position of the mark when it is determined that there is an influence of contamination; A drawing device that performs the following functions:

2. In claim 1, The mark is a first portion extending in a first direction from a center of the mark; a second portion extending from a center of the mark in a second direction opposite to the first direction; and The control unit determining whether or not there is an effect of contamination based on the signal obtained by scanning the first portion; a process of changing a scanning position in the first portion when it is determined that there is an influence of contamination; Repeat a writing apparatus that changes the scanning position from the first portion to the second portion when it is determined that there is an influence of contamination at all scanning positions of the first portion;

3. In claim 2, The control unit changes the scanning position from the first portion to the second portion when it determines that the number of times the process of changing the scanning position in the first portion has been repeated is equal to or greater than a predetermined number.

4. In claim 1, A plurality of the marks are provided, The control unit a process of determining whether or not there is an influence of contamination based on the signal obtained by scanning a first mark of the plurality of marks; a process of changing a scanning position of the first mark when it is determined that there is an influence of contamination; Repeat a writing apparatus that, when it is determined that there is an influence of contamination at all scanning positions of the first mark, changes the scanning position from the first mark to a second mark of the plurality of marks.

5. In claim 1, The control unit a process of receiving information on the type of correction using the mark; A process of setting a range for setting a scanning position based on the information on the type of correction; A drawing device that performs the following functions:

6. In claim 5, The mark is A first region; a second region having a larger distance from the center of the mark than the first region; and The control unit If the information on the type of correction is information on the first correction, the range in which the scanning position is set is set to the first region; When the information on the type of correction is information on a second correction different in type from the first correction, the imaging device sets a range for setting the scanning position to the second region.

7. In any one of claims 1 to 6, The control unit determines whether or not there is an influence of contamination based on the waveform of the signal.

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