Multi charged particle beam drawing method and multi charged particle beam drawing apparatus

Abstract

A method and apparatus for depicting multiple charged particle beams are provided, which can suppress the increase of array distortion while solving the problem of beam position variation caused by the spatial retention of secondary electrons and the charging of deflector electrodes. The method for depicting multiple charged particle beams of this embodiment includes: a step of forming a multiple charged particle beam that irradiates a substrate to be depicted; a step of deflecting the multiple charged particle beam to a position with a predetermined deflection offset, such that the state of each deflection voltage applied to the multiple electrodes of the electrostatic positioning deflector is zero; and a step of irradiating the substrate with the multiple charged particle beam, and applying a positive common voltage to each of the deflection voltages and applying it to each electrode of the positioning deflector.

Description

[0001] This application is based on Japanese Patent Application 2021-135680 (filed August 23, 2021) and Japanese Patent Application 2022-087811 (filed May 30, 2022), and enjoys the priority of those applications. This application incorporates the entire contents of the basic applications by reference. Technical Field

[0002] This invention relates to a method and apparatus for depicting multiple charged particle beams. Background Technology

[0003] With the increasing integration of LSIs, the required linewidths of circuits in semiconductor devices are becoming smaller year by year. To form the desired circuit patterns in semiconductor devices, the following method is used: a reduction projection exposure device is used to reduce and transfer a high-precision original pattern (mask, or, especially, intermediate mask used in steppers and scanners) formed on a quartz wafer onto the wafer. The high-precision original pattern is drawn by an electron beam lithography device using what is known as electron beam lithography.

[0004] As a type of electron beam mapping apparatus, multi-electron beam mapping apparatuses using multiple beams are known. Compared to mapping apparatuses using a single electron beam, multi-electron beam mapping apparatuses can significantly increase productivity because they can irradiate more beams at once.

[0005] In a multi-electron beam mapping apparatus, each emitted beam is focused onto the surface of the substrate to be mapped using an objective lens, and a static lens is used to dynamically correct the focus during mapping in a manner corresponding to the unevenness of the substrate surface (dynamic focusing). When this static lens is used within a negative voltage range, secondary electrons generated by electron beam mapping return to the substrate surface, causing the resist to become charged, which hinders the improvement of the positional accuracy of the mapped pattern.

[0006] To suppress the effects caused by the return of secondary electrons, it is preferable to use an electrostatic lens within a positive voltage range on the substrate surface to guide secondary electrons upward from the substrate surface.

[0007] However, when an electrostatic lens is used within a positive voltage range, secondary electrons from the substrate surface decelerate rapidly after passing through the electrostatic lens and remain in the beam track at a high density. Alternatively, non-conductive dirt (contaminants) on the inner surface of the deflector electrodes may become charged, causing changes in the electric field near the electron beam. This results in changes in the electron beam track and deterioration of the beam position accuracy.

[0008] Non-Patent Literature 1 (Hirofumi Morita, Junichi Kato and Nobuo Shimazu, Basic characteristics of beam position drift and field stitching error caused by electron beam column charging, Japanese Journal of Applied Physics Vol.35(1996), Part 1, No.7, July 1996, pp.4121-4127.) reports a phenomenon that reduces drift by performing deflection (deflection offset) in a narrow region centered on the deflected front end. However, in the variable-shape beam drawing apparatus that is widely used in industry to date and is the subject of the experiment in Non-Patent Literature 1, when the size of the deflection region used in the drawing has a significant impact on the drawing productivity, and drawing is performed only in a narrow region at the deflected front end, a problem arises where productivity is greatly reduced. For this reason, the phenomenon described in Non-Patent Document 1, where drift is reduced if deflection is performed in a narrow region centered on the deflecting tip, is extremely difficult to implement in practice and is unlikely to be used in industry.

[0009] In multi-beam drawing devices, unlike variable-shape beam devices, there is little concern about reduced productivity even if the deflection region size is small, thus creating the possibility of utilizing the aforementioned phenomenon.

[0010] However, by performing deflection (deflection offset) to reduce drift, a new problem arises: increased array distortion (displacement from the ideal position of each individual beam relative to the others). Reducing array distortion is a newly emerging requirement in multi-beam optical systems. Unlike variable-shape beam optical systems that form smaller beams (around 1 μm or less) with very large array beams (e.g., approximately 100 μm in length and width), multi-beam optical systems are prone to increased array distortion, making it very difficult yet crucial to reduce it in the design. Here, if deflection offset is performed to reduce drift, the array distortion caused by the deflection increases, leading to a deterioration in rendering accuracy.

[0011] To reduce array distortion caused by deflection, it is known that placing the deflector within the lens magnetic field (the so-called in-tube secondary electron detector configuration) is effective. To further reduce array distortion caused by deflection, it is often necessary to configure the deflector in multiple stages and optimize the deflection amount and direction of each deflector. However, for the high distortion reduction required by multi-beam mapping devices, as a prerequisite for optimization, it is practically necessary to place one deflector within the lens magnetic field (in-tube secondary electron detector configuration). On the other hand, to obtain sufficient correction sensitivity (focus correction sensitivity, rotation correction sensitivity) in practical use, it is necessary to place the electrostatic correction lens within the lens magnetic field (again, in-tube secondary electron detector configuration) (see Japanese Patent Application Publication No. 61-101944 and Japanese Patent Application Publication No. 2013-197289). As a result, it is necessary to place the correction lens near the center of the magnetic pole, and the deflector close to directly above the correction lens and positioned where the lens magnetic field exists.

[0012] However, a new problem arises: if the deflector is placed close to the electrostatic correction lens, secondary electrons from the sample surface decelerate and become lodged at the point where they enter the deflector after passing through the correction lens, causing instability (drift) in the primary beam. As a technique to address the drift caused by lodged electrons during deceleration, Japanese Patent Application Publication No. 2018-170435 discloses a technique of placing an electrode with a positive voltage directly above the electrostatic correction lens. Furthermore, Japanese Patent Application Publication No. 2019-212766 discloses a technique of extending the electrode of the electrostatic correction lens with the applied positive voltage upstream to a position where the lens magnetic field decays. However, when using these techniques, the presence of the added electrode and the extended correction lens electrode leads to the following problem: the deflector must be positioned at a position where the magnetic field decays upstream from the lens magnetic poles (i.e., it is impossible to configure a secondary electron detector inside the lens barrel), making it difficult to reduce array distortion caused by deflection.

[0013] As described above, in multi-beam optical systems, in order to reduce the return of secondary electrons to the substrate, it is not possible to simultaneously reduce beam position variation caused by secondary electron deflector charging, reduce beam position variation caused by secondary electron retention, and reduce multi-beam array distortion under the condition that the electrostatic lens operates within a positive voltage range. Summary of the Invention

[0014] This invention provides a method and apparatus for depicting multiple charged particle beams that can suppress the increase in array distortion while addressing the variation in beam position caused by the spatial retention of secondary electrons and the charging of deflector electrodes.

[0015] One aspect of the present invention is a multi-charged particle beam drawing method comprising: a step of forming a multi-charged particle beam that irradiates a substrate to be drawn; a step of deflecting the multi-charged particle beam to a position with a predetermined deflection offset such that there is no state in which each deflection voltage applied to a plurality of electrodes of an electrostatic positioning deflector is zero; and a step of irradiating the substrate with the multi-charged particle beam, and applying a positive common voltage to each of the deflection voltages and applying it to each electrode of the positioning deflector. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a multi-charged particle beam mapping apparatus according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of a substrate with a shaped aperture array.

[0018] Figure 3 This is a cross-sectional view of the second objective lens.

[0019] Figure 4 (a) and (b) are diagrams illustrating the orbitals of the secondary electrons in the comparative example.

[0020] Figure 5 It is a diagram illustrating the deflectable range and depicting the deflection area.

[0021] Figure 6 (a), (b), (c) and (d) are diagrams depicting the location of the deflection region to illustrate the fixed polarity of the deflection voltage.

[0022] Figure 7 This is a diagram showing an example of the configuration of a positioning deflector.

[0023] Figure 8 Figures (a) and (b) are diagrams illustrating examples of the configuration of a positioning deflector.

[0024] Figure 9 (a), (b), and (c) are diagrams depicting the location of the deflection region to illustrate the fixed polarity of the deflection voltage.

[0025] Figure 10 (a) and (b) are diagrams depicting the location of the deflection region to illustrate that the polarity of the deflection voltage is fixed.

[0026] Figure 11 This is a cross-sectional view of the second objective lens when a magnetic field deflector is placed near an electrostatic positioning deflector.

[0027] Figure 12 (a) and (b) are diagrams illustrating the orbits of secondary electrons.

[0028] Figure 13It is a diagram illustrating the structure of the positioning deflector and the voltage applied to each electrode.

[0029] Figure 14 It is a diagram illustrating the structure of the positioning deflector and the voltage applied to each electrode.

[0030] Symbol Explanation

[0031] 10: Drawing section; 12: Electron optical lens tube; 14: Electron gun; 16: Illumination lens; 18: Shaping aperture array substrate; 20: Blanking aperture array substrate; 22: Projection lens; 24: Stop aperture; 26: First objective lens; 28: Positioning deflector; 29: Magnetic field deflector; 30: Second objective lens; 32: Focus correction lens; 40: Drawing chamber; 42: XY stage; 44: Substrate; 60: Control section. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. In the embodiments, an electron beam configuration will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and may also be an ion beam, etc.

[0033] Figure 1 The depiction apparatus shown includes: a depiction unit 10, which irradiates an object such as a mask or wafer with an electron beam and depicts a desired pattern; and a control unit 60, which controls the operation of the depiction unit 10. The depiction unit 10 is an example of a multi-beam depiction apparatus having an electron optical lens 12 and a depiction chamber 40.

[0034] Within the electron optical lens barrel 12, an electron gun (emitter) 14, an illumination lens 16, a forming aperture array substrate 18, a blanking aperture array substrate 20, a projection lens 22, a stop aperture (aperture limiting component) 24, a first objective lens 26, a positioning deflector 28, a second objective lens 30, and a focus correction lens 32 are disposed. An XY stage 42 is disposed within the drawing chamber 40. On the XY stage 42, a substrate 44, i.e., a mask blank, which is the object to be drawn, is placed.

[0035] The substrate 44 includes, for example, a wafer and an exposure mask. The exposure mask transfers a pattern onto the wafer using a reduction projection type exposure apparatus such as a stepper or scanner that uses an excimer laser as a light source, or an extreme ultraviolet exposure apparatus. Furthermore, the substrate 44 also includes a mask that already has a pattern formed on it. For example, because a Levinson type mask requires two drawing steps, a second pattern is sometimes drawn on the object that has already been drawn once and processed into a mask.

[0036] like Figure 2As shown, on the shaped aperture array substrate 18, openings (first openings) 18A with a longitudinal length of m columns and a transverse length of n rows (m, n≥2) are formed at a specified spacing. Each opening 18A is formed as a rectangle of the same size and shape. The shape of the openings 18A can be circular. A portion of the electron beam B passes through these multiple openings 18A, thereby forming a multi-beam MB.

[0037] A blanking aperture array substrate 20 is disposed below a shaped aperture array substrate 18 and has through holes 20A (second openings) in the shaped aperture array substrate 18 corresponding to each opening 18A. A blanking device (not shown) consisting of a pair of electrodes is disposed in each through hole 20A. One blanking device is fixed at ground potential, while the other is switched to a potential different from ground potential. The electron beam passing through each through hole 20A is independently deflected by the voltage applied to the blanking device. Thus, multiple blanking devices perform blanking deflection on the corresponding beams in the multiple beams MB passing through the multiple openings 18A of the shaped aperture array substrate 18.

[0038] The stop aperture 24 blocks the beam deflected by the blanking device. The beam not deflected by the blanking device passes through the opening 24A (third opening) formed in the center of the stop aperture 24. The stop aperture 24 is located on the imaging surface at the intersection (light source image) where the beam expansion decreases in order to reduce beam leakage during individual blanking based on the blanking aperture array substrate 20.

[0039] The control unit 60 includes a control computer 62, a deflection control circuit 64, and a lens control circuit 66. The deflection control circuit 64 controls the applied voltage to the electrodes of the blanking device and the positioning deflector 28 disposed on the blanking aperture array substrate 20. The lens control circuit 66 controls the applied voltage to the illumination lens 16, the projection lens 22, the first objective lens 26, the second objective lens 30, and the focus correction lens 32. For example, the lens control circuit 66 controls the voltage applied to the focus correction lens 32 based on the surface height of the substrate 44 detected by the Z-sensor (not shown), performing focus correction (dynamic focusing).

[0040] An electron beam B emitted from electron gun 14 illuminates the entire shaped aperture array substrate 18 substantially perpendicularly through illumination lens 16. The electron beam B passes through multiple openings 18A in the shaped aperture array substrate 18, thereby forming a multi-beam MB composed of multiple electron beams. The multi-beam MB passes through the corresponding blanking devices in the blanking aperture array 20.

[0041] The multiple electron beams MB passing through the blanking aperture array substrate 20 are reduced in size by the projection lens 22 and travel toward the opening 24A at the center of the stop aperture 24. Here, the electron beams deflected by the blanking device of the blanking aperture array substrate 20 are deviated from their position from the opening 24A of the stop aperture 24 and are blocked by the stop aperture 24. On the other hand, the electron beams not deflected by the blanking device pass through the opening 24A of the stop aperture 24. Blanking control is performed by using the pass / block (ON / OFF) of the blanking device to control the pass / block of the beams.

[0042] Thus, the stop aperture 24 blocks the beams deflected by the blanking device of the blanking aperture array substrate 20 in a beam-blocking state.

[0043] The multi-beam MB passing through the stop aperture 24 is focused by the first objective lens 26, the second objective lens 30 and the focus correction lens 32 to form a pattern image with the desired reduction ratio, and is then irradiated onto the substrate 44.

[0044] A positioning deflector 28, positioned between the first objective lens 26 and the second objective lens 30, deflects the multi-beam MB to a desired position on a substrate 44 placed on a continuously moving XY stage 42. The positioning deflector 28 can be a quadrupole deflector with multiple electrodes, such as a quadrupole deflector with four electrodes or an octupole deflector with eight electrodes. By changing the voltage applied to each electrode of the positioning deflector 28, the beam deflection position (the beam irradiation position on the substrate 44) can be changed.

[0045] The area irradiated by the multi-beam MB onto the substrate 44 is as wide as 100 micrometers square. Therefore, even if the area to be deflected by the positioning deflector 28 (the deflection area) is narrower than the size of the multi-beam MB, there will be no problem with deflection productivity. For example, a size from a few micrometers square to about 10 micrometers square is sufficient. This is very different from the case of variable-shape electron beam deflection apparatuses, which require a deflection area as wide as about 100 micrometers square to achieve deflection productivity.

[0046] The focus correction lens 32 is positioned downstream of the multi-beam MB in the direction of travel, compared to the positioning deflector 28.

[0047] Electromagnetic lenses (magnetic field type lenses) are used for the illumination lens 16, projection lens 22, first objective lens 26, and second objective lens 30, but it is acceptable to use electrostatic lenses for some or all of them. The focus correction lens 32 is a component that dynamically adjusts the focus by changing the height of the surface of the substrate 44. An electrostatic lens is used, but an electromagnetic lens (including a coil that generates an axisymmetric magnetic field) can also be used. In addition, it can be composed of a multi-stage lens system in which the applied voltage and excitation current change in a certain relationship. Alternatively, the second objective lens 30 can also function as the focus correction lens 32, or the second objective lens 30 and the focus correction lens 32 can be configured to perform focus adjustment in a certain relationship.

[0048] The second objective lens 30 is an electromagnetic lens, such as... Figure 3 As shown, the device includes a coil 30a and a yoke 30b for housing the coil 30a. The yoke 30b is made of a material with high magnetic permeability, such as iron, and has a cutout (pole piece 30c) in a portion of it.

[0049] The magnetic field lines generated by the current flowing through the coil 30a leak into space through the pole piece 30c, thus generating a magnetic field.

[0050] The focus correction lens 32 is configured, for example, to fit the interior of the second objective lens 30, for example, the height of the electrode 30c. The focus correction lens 32 is an electrostatic lens and has an annular electrode. A positive voltage is applied to this electrode relative to the substrate surface, and the focus correction lens 32 is used relative to the substrate surface within a positive voltage range.

[0051] When the multi-beam MB (primary beam) is irradiated onto the substrate 44, secondary electrons are emitted from the substrate surface. By using a focus-correcting lens 32 within a positive voltage range, the secondary electrons are guided upward from the substrate surface and travel upward within the electron optics barrel 12. This suppresses the return of secondary electrons to the substrate surface, thereby suppressing positional changes caused by the charging of the resist.

[0052] During the painting process, the resist on the surface of the substrate 44 may sometimes evaporate due to beam irradiation, causing contaminants (dirt) to adhere to the surfaces of the multiple electrodes of the positioning deflector 28. Secondary electrons traveling upward within the electron optical barrel 12 may become charged upon reaching the contaminants on the electrode surfaces of the positioning deflector 28, potentially causing changes in the trajectory of the multi-beam MB.

[0053] In conventional drawing apparatuses, during the operation of changing the beam deflection position (beam irradiation position in substrate 44), such as Figure 4As shown in (a) and (b), the polarity of the deflection voltage applied to each electrode of the positioning deflector 28 changes. If the polarity of the deflection voltage changes, the strength and direction of the electric field within the positioning deflector 28 change significantly, and the arrival position of the secondary electrons, i.e., their charged position, changes significantly across the electrodes. This significant change in the charged position leads to a significant change in the electric field near the beam, resulting in a large beam irradiation position shift (drift).

[0054] Therefore, in this embodiment, by applying an offset (deflection offset) to the deflection position of the positioning deflector 28, that is, by displacing the deflection position, the secondary electrons are removed from the vicinity of the beam center and move in a generally fixed lateral direction, being guided to a defined area such as the deflector surface. For example, as Figure 5 As shown, the deflection region R1 is shifted within the deflectable range R0 so that the deflection voltage of all electrodes excluding the origin of the deflection voltage within the deflection region R1, i.e., excluding the positioning deflector 28, is 0 (all deflection voltages are 0). Here, the deflectable range R0 is the range within which the deflection amplifier included in the deflection control circuit 64 can be deflected at its maximum output. The deflection region R1 is the deflection region required in the deflection process. By setting it to be the origin excluding the deflection voltage within the deflection region R1, as... Figure 12 As shown in (a) and (b), the change in the arrival position of the secondary electron, i.e. the change in the charged position, is suppressed relative to the change in the deflection position, thus suppressing the beam irradiation position variation (drift).

[0055] Furthermore, it is even more effective if the deflection offset is set so that the polarity of the deflection voltage of each electrode (each electrode) of the positioning deflector 28 remains constant. To fix the polarity of the deflection voltage of each electrode, in a four-electrode deflector, as long as... Figure 6 The deflection region R1 can be included in any of the regions R11 to R14 shown in (a) to (d). Therefore, since the area where secondary electrons hit the deflection electrode is further defined, the range of the charged position is also further defined. As a result, changes in the intensity and direction of the electric field within the positioning deflector 28 are suppressed, and beam irradiation position variations (drift) are suppressed, improving beam position accuracy.

[0056] Furthermore, when "the deflection offset is set so that the polarity of the deflection voltage of each electrode is fixed", the condition "excluding all states where the deflection voltage is 0" is automatically (and necessarily) satisfied. Therefore, "fixed polarity" is a further condition that limits "all deflection voltages to 0".

[0057] Furthermore, conditions related to the voltage applied to the deflector contribute more directly to reducing drift. Ultimately, as a result, the beam deflection position and deflection region on the substrate surface are displaced, meaning that the beam deflection position and deflection region on the substrate surface themselves may not directly contribute to reducing drift.

[0058] Here, by setting the motion parameters, a fixed deflection offset is always applied during drawing, so that the origin of the deflection during drawing is located at the position displaced by the deflection offset, thereby allowing the beam to be irradiated to the desired position on the substrate 44. The drawing deflection area usable due to the deflection offset is narrower, but since a wide drawing deflection area is not required in a multi-beam drawing apparatus, this is not a problem in practical use. Furthermore, fixing the deflection offset during the drawing operation is most effective in reducing drift. Additionally, as mentioned above, as long as the conditions such as "deflection voltage not exceeding 0" or "polarity is fixed" are met, the deflection offset can be slightly varied during the drawing operation. In this case, the position of the XY stage 42 needs to be adjusted according to the amount of change in the deflection offset.

[0059] Figure 7 This illustrates an example of the configuration of the positioning deflector 28. Figure 7 In the example shown, the positioning deflector 28 is an electrostatic quadrupole deflector with four electrodes 28a to 28d. With the deflection offset set to (X0, Y0), the deflection amount used for pattern drawing based on the pattern position of the drawing data set to (X, Y), and the deflection sensitivity coefficient set to k, the deflection voltages V1 to V4 applied to the electrodes 28a to 28d are as follows.

[0060] V1 = k(X0 + X)

[0061] V2 = k(Y0 + Y)

[0062] V3 = k(-X0-X)

[0063] V4 = k(-Y0-Y)

[0064] Consider setting the deflectable range in the x-direction to start from -X. M To X M Set the deflection range in the y-direction to -Y. M To Y M Set the drawing deflection region in the x-direction to start from -X. W To X W Set the drawing deflection region in the y-direction to start from -Y. W To Y W The situation. For example... Figure 5As shown, a deflection offset (X0, Y0) that is used to locate the origin of the deflection voltage within the deflection region R1, excluding the origin of the deflection voltage, and where the polarity of the deflection voltage of each electrode of the deflector 28 is fixed, can be achieved by satisfying the following condition.

[0065] X W <|X0|≤X M -X W

[0066] Y W <|Y0|≤Y M -Y W

[0067] The deflection offset (X0, Y0) that satisfies the above condition is calculated in advance, and the deflection offset is stored in the memory (not shown) of the control unit 60.

[0068] During the drawing process, the control computer 62 reads the drawing data from the storage device and performs multi-level data conversion processing to generate the device's inherent emission data. The emission data defines the illumination amount and illumination position coordinates for each emission. The illumination position coordinates are calculated using the aforementioned deflection offset (X0, Y0) as the origin of the deflection.

[0069] The control computer 62 outputs the irradiation amount of each emission to the deflection control circuit 64 based on the emission data. The deflection control circuit 64 divides the input irradiation amount by the current density to calculate the irradiation time t. Then, when performing the corresponding emission, the deflection control circuit 64 applies a deflection voltage to the corresponding blanker of the blanking aperture array substrate 20 so that the blanker passes through the beam during the irradiation time t.

[0070] Furthermore, the deflection control circuit 64 calculates the deflection amount (X, Y) for drawing, adds or subtracts the deflection offset amount (X0, Y0), and applies the aforementioned deflection voltages V1 to V4, multiplied by the deflection sensitivity coefficient k, to each electrode 28a to 28d of the positioning deflector 28 to irradiate the beam at the irradiation position shown in the emission data. Additionally, when calculating the aforementioned deflection amount for drawing, the position information of the XY stage 42 is obtained from a position measuring device (not shown) such as a laser length measuring device and utilized.

[0071] Thus, by setting the polarity of the deflection voltage of each deflection electrode of the positioning deflector 28 to be fixed, secondary electrons are guided to the defined area of ​​the positioning deflector 28, suppressing changes in the charge of the deflector, thereby stabilizing the beam.

[0072] Positioning deflector 28 can be used Figure 8 The octet deflector with eight electrodes 28a to 28h shown in (a) and (b) is shown. Figure 8The deflectors shown in (a) and (b) have a phase difference of 22.5 degrees. In this specification, as... Figure 8 As shown in (a), the deflector configured such that the deflection coordinate axis passes through the center of the gap between the deflection electrodes is called a 22.5-degree rotational configuration, as... Figure 8 As shown in (b), a deflector configured such that the deflection coordinate axis passes through the center of the deflection electrode is called a 0-degree rotation configuration.

[0073] exist Figure 8 In the 22.5-degree rotation configuration shown in (a), the deflection voltages V1 to V8 applied to electrodes 28a to 28h are expressed as follows using deflection offset (X0, Y0), deflection amount (X, Y) for plotting, and deflection sensitivity coefficient k.

[0074] V1 = k{(X0+X)+a(Y0+Y)}

[0075] V2 = k{(Y0+Y)+a(X0+X)}

[0076] V3 = k{(Y0+Y)-a(X0+X)}

[0077] V4 = k{-(X0+X)+a(Y0+Y)}

[0078] V5 = k{-(X0+X)-a(Y0+Y)}

[0079] V6 = k{-(Y0+Y)-a(X0+X)}

[0080] V7 = k{-(Y0+Y)+a(X0+X)}

[0081] V8 = k{(X0+X)-a(Y0+Y)}

[0082]

[0083] In the 22.5-degree rotation configuration, to fix the polarity of the deflection voltage of each electrode of the positioning deflector 28, the deflection area only needs to be contained within... Figure 9 (a) shows the range from 22.5 degrees to 67.5 degrees and the regions Ra (Ra1 to Ra4) that extend every 90 degrees therefrom. Figure 9 (b) shows the region Rb (Rb1, Rb2) from -22.5 degrees to 22.5 degrees and rotated 180 degrees from there, or Figure 9 It can be any one of the regions Rc (Rc1, Rc2) shown in (c) from 67.5 degrees to 112.5 degrees and rotated 180 degrees from there.

[0084] In order to include the deflection region within region Ra, the deflection offset (X0, Y0) only needs to satisfy the following condition.

[0085]

[0086]

[0087] |X0|≤X M -X W

[0088] |Y0|≤Y M -Y W

[0089] In order to include the deflection region in the region Rb, the deflection offset (X0, Y0) only needs to satisfy the following condition.

[0090]

[0091]

[0092] |X0|≤X M -X W

[0093] |Y0|≤Y M -Y W

[0094] In order to include the deflection region within region Rc, the deflection offset (X0, Y0) only needs to satisfy the following condition.

[0095]

[0096]

[0097] |X0|≤X M -X W

[0098] |Y0|≤Y M -Y W

[0099] exist Figure 8 In the 0-degree rotation configuration shown in (b), the deflection voltages V1 to V8 applied to electrodes 28a to 28h are expressed as follows using deflection offset (X0, Y0), deflection amount (X, Y) for plotting, and deflection sensitivity coefficient k'.

[0100] V1 = k'(X0 + X)

[0101] V2=k'b{(X0+X)+(Y0+Y)}

[0102] V3 = k'(Y0 + Y)

[0103] V4=k'b{-(X0+X)+(Y0+Y)}

[0104] V5 = -k'(X0 + X)

[0105] V6 = -k'b{(X0+X)+(Y0+Y)}

[0106] V7 = -k'(Y0 + Y)

[0107] V8 = -k'b{-(X0+X)+(Y0+Y)}

[0108] b = 1 / √2 ≈ 0.707

[0109] In the 0-degree rotation configuration, to fix the polarity of the deflection voltage of each electrode of the positioning deflector 28, the deflection area only needs to be contained within... Figure 10 (a) shows the region Rd (Rd1 to Rd4) symmetrical about the x-axis, y-axis, and origin, ranging from 0 to 45 degrees. Figure 10 It can be any one of the regions Re (Re1 to Re4) shown in (b) which are 45 degrees to 90 degrees and symmetrical about the x-axis, y-axis and origin.

[0110] In order to include the deflection region within region Rd, the deflection offset (X0, Y0) only needs to satisfy the following condition.

[0111] |Y0|+Y W <|X0|-X W

[0112] |X0|≤X M -X W

[0113] |Y0|≤Y M -Y W

[0114] |Y0|>Y W

[0115] In order to include the deflection region in region Re, the deflection offset (X0, Y0) only needs to satisfy the following condition.

[0116] |X0|+X W <|Y0|-Y W

[0117] |X0|≤X M -X W

[0118] |Y0|≤Y M -YW

[0119] |X0|>X W

[0120] like Figure 13 As shown, if a common voltage Vc, which is positive relative to the substrate surface, is applied to the voltage applied to each electrode of the positioning deflector 28, drift can be reduced more reliably. This common voltage Vc is preferably a positive voltage V applied to the focus correction lens 32. F The value is above the upper limit. Therefore, the secondary electrons after passing through the focus correction lens 32 move to the positioning deflector 28 without deceleration. Thus, it is possible to prevent the secondary electrons from lingering between the focus correction lens 32 and the positioning deflector 28, improving the beam illumination position accuracy. Although the electrostatic deflector is positioned close to the focus correction lens, since drift caused by the lingering of secondary electrons does not occur, the deflector can be positioned at the location where the lens magnetic field exists, reducing array distortion caused by deflection. Even with an applied deflection offset, the increase in array distortion can be suppressed. Furthermore, as... Figure 14 As shown in the example, by setting the positioning deflector to level 2, placing one positioning deflector 28 close to the focal correction lens, and optimizing the deflection amount and direction of the two positioning deflectors 28 and 28', the increase in array distortion caused by the deflection offset can be further reduced.

[0121] In addition, a ring-shaped ground electrode is usually arranged between the electrodes of the electrostatic deflector and the focus correction lens where the voltage is applied. However, if such a ground electrode is not arranged and the electrodes of the two (where the voltage is applied) are arranged close together, there will be no temporary deceleration (deceleration of secondary electrons) in a short range near the ground electrode. Therefore, it is possible to further reliably reduce drift caused by stagnation.

[0122] For example, in the case of Figure 7 In the case of a positioning deflector composed of a quadrupole deflector, the voltage applied to each electrode is as follows.

[0123] V1 = Vc + k(X0 + X)

[0124] V2 = Vc + k(Y0 + Y)

[0125] V3 = Vc + k(-X0 - X)

[0126] V4 = Vc + k(-Y0 - Y)

[0127] In the above formula, the left side represents the applied voltage to each electrode, the first term (Vc) on the right side is the common voltage, and the second term on the right side (the term multiplied by k) is the deflection voltage already explained. Furthermore, in this specification, the terms "applied voltage" and "deflection voltage" are distinguished for the deflector. "Applied voltage" is the voltage applied to each electrode, obtained by adding the common voltage and the deflection voltage. "Deflection voltage" is the voltage that contributes to the generation of the deflection electric field, thereby deflecting the incident beam and secondary electrons. Additionally, when no common voltage is applied, the "applied voltage" and "deflection voltage" for the deflector are the same.

[0128] like Figure 11 As shown, a magnetic field deflector 29 can be placed near the electrostatic positioning deflector 28. By energizing the magnetic field deflector 29, a deflection offset opposite to that of the positioning deflector 28 is generated, thereby canceling out part or all of the deflection offset of the incident beam (multi-beam MB) on the substrate surface, further reducing the distortion and aberration of the incident beam. The energizing amount of the magnetic field deflector 29 only needs to be set according to the deflection offset of the positioning deflector 28 and does not need to be changed in conjunction with the deflection positioning operation. Alternatively, based on canceling out the deflection offset of the positioning deflector 28, a portion of the energizing amount can be changed in conjunction with the deflection positioning operation. When the magnetic field deflector 29 cancels out all of the deflection offset of the positioning deflector 28, the deflection area (delineated on the substrate surface) Figure 5 Since the center of R1 is 0, it does not actually generate a bias in the deflection position. However, as mentioned above, it is not the deflection position or the deflection region itself on the substrate surface that directly affects the reduction of drift. That is, by satisfying the conditions related to the deflection voltage mentioned above, the effect of reducing drift can be obtained. In addition, since the deflection direction of the magnetic field deflection is opposite to the direction of beam travel, it does not hinder the deflection of secondary electrons traveling in the opposite direction to the incident beam.

[0129] Furthermore, this invention is not directly limited to the above-described embodiments, and can be embodied by modifying the constituent elements during the implementation phase without departing from its spirit. Moreover, various inventions can be formed through appropriate combinations of the multiple constituent elements disclosed in the above embodiments. For example, some constituent elements can be deleted from all the constituent elements shown in the embodiments. Furthermore, constituent elements applicable to different embodiments can be appropriately combined.

Claims

1. A method for depicting multiple charged particle beams, comprising: A process for forming a beam of multiple charged particles that irradiates a substrate onto which the object is being depicted; The process of deflecting the aforementioned multi-charged particle beam to a position with a predetermined deflection offset, such that it does not include the process of applying zero deflection voltages to the electrodes of the electrostatic positioning deflector; and The process of irradiating the substrate with the aforementioned multiple charged particle beams The focus correction lens, positioned downstream of the aforementioned positioning deflector in the direction of travel of the multiple charged particle beams, operates within a positive voltage range. A positive common voltage, which is a value above the upper limit of the positive voltage applied to the focus correction lens, is added to each of the above deflection voltages and applied to each electrode of the positioning deflector.

2. The method for depicting multiple charged particle beams according to claim 1, wherein, The process includes the following steps: deflecting the above-mentioned multi-charged particle beam to a position with the above-mentioned specified deflection offset, so that the polarity of the voltage of each electrode is fixed within the range of the above-mentioned deflection voltages.

3. The method for depicting multiple charged particle beams according to claim 1, wherein, A magnetic field deflector is used to generate a deflection in the opposite direction to the aforementioned deflection offset.

4. A multi-charged particle beam mapping device, comprising: An electrostatic positioning deflector has multiple electrodes to deflect a beam of multiple charged particles irradiating a substrate of the object being depicted. The deflection control circuit deflects the multiple charged particle beams to a position with a predetermined deflection offset, so as to avoid a state in which all the deflection voltages applied to the multiple electrodes are zero. The focus correction lens is positioned downstream of the aforementioned positioning deflector in the direction of travel of the multiple charged particle beams. as well as The lens control circuit ensures that the aforementioned focus-correcting lens operates within a positive voltage range. A positive common voltage, which is a value above the upper limit of the positive voltage applied to the focus correction lens, is added to each of the above deflection voltages and applied to each electrode of the positioning deflector.

5. The multi-charged particle beam mapping apparatus according to claim 4, wherein, The aforementioned deflection control circuit deflects the aforementioned multi-charged particle beam to a position plus the aforementioned predetermined deflection offset, so that the polarity of the voltage of each electrode is fixed within the range of the aforementioned deflection voltages.

6. The multi-charged particle beam mapping apparatus according to claim 4, wherein, It also has a magnetic field deflector that generates a deflection in the opposite direction to the aforementioned deflection offset.

7. The multi-charged particle beam mapping apparatus according to claim 4, wherein, The aforementioned positioning deflector consists of two deflectors.

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