Charged particle beam writing method and charged particle beam writing apparatus

Abstract

A charged particle beam drawing method and a charged particle beam drawing device that suppress fluctuations in beam position are provided. The charged particle beam drawing method according to the present embodiment comprises: a process of deflecting a charged particle beam to a position where a deflection offset is added so that a state in which any of the deflection voltages becomes zero is not included in the range of each deflection voltage applied to each of the plurality of electrodes of an electrostatic positioning deflector; a process of irradiating the charged particle beam onto a substrate; and a process of changing the quadrant of the deflection offset based on the origin of the deflection voltage where the total deflection voltage becomes zero at a predetermined timing or based on the drift amount of the charged particle beam.

Description

Technology Field

[0001] This application enjoys priority based on Japanese Patent Application No. 2024-090875 (filing date: June 4, 2024). By referring to this basic application, this application includes all the contents of the basic application.

[0002] The present invention relates to a charged particle beam drawing method and a charged particle beam drawing device. Background Technology

[0003] With the high integration of LSIs, the circuit linewidth required for semiconductor devices is becoming finer year by year. To form desired circuit patterns on semiconductor devices, a method is employed in which a high-precision original pattern (called a mask, or specifically a reticle used in steppers or scanners) formed on quartz is reduced and transferred onto a wafer using a reduction projection exposure device. The high-precision original pattern is drawn by an electron beam lithography device, and so-called electron beam lithography technology is utilized.

[0004] As a form of electron beam lithography device, a multi-electron beam lithography device using multiple beams is known. Compared to a lithography device that uses a single electron beam, a multi-electron beam lithography device can irradiate many beams at once, so throughput can be greatly improved.

[0005] In a multi-electron beam lithography device, the beam of each shot is focused onto the surface of the substrate to be lithographed using an objective lens, and dynamic focus correction (dynamic focus) is performed during lithography using an electrostatic lens to correspond to the irregularities on the substrate surface. When this electrostatic lens is operated in a negative voltage range, secondary electrons generated by electron beam lithography return to the substrate surface, causing charging of the resist and hindering the improvement of dimensional accuracy of the lithograph pattern.

[0006] In order to suppress the effects of the return of secondary electrons, it is desirable to operate an electrostatic lens on the substrate surface in a positive voltage range and induce secondary electrons upward from the substrate surface.

[0007] However, when the electrostatic lens is operated in a positive voltage range, secondary electrons from the surface of the substrate rapidly decelerate after passing through the electrostatic lens and remain in high density on the beam trajectory, or become charged on non-conductive contamination on the inner surface of the deflector electrode, causing the electric field near the electron beam to change and the trajectory of the electron beam to change, thereby degrading the beam position accuracy. The problem to be solved

[0008] One aspect of the present invention provides a charged particle beam drawing method and a charged particle beam drawing device that suppress variations in beam position. means of solving the problem

[0009] A charged particle beam drawing method according to one embodiment of the present invention comprises: a process of deflecting a charged particle beam to a position where a deflection offset is added so that a state in which the deflection voltage of any of the deflection voltages becomes zero is not included in the range of each deflection voltage applied to each of the plurality of electrodes of an electrostatic positioning deflectioner; a process of irradiating the charged particle beam onto a substrate; and a process of changing the quadrant of the deflection offset based on the origin of the deflection voltage where the total deflection voltage becomes zero at a predetermined timing or based on the drift amount of the charged particle beam.

[0010] A charged particle beam drawing device according to one embodiment of the present invention comprises a electrostatic positioning deflector having a plurality of electrodes and deflecting a charged particle beam irradiated onto a substrate to be drawn, and a deflection control circuit that deflects the charged particle beam at a position where a deflection offset is added so as not to include a state in which the deflection voltage of any of the deflection voltages becomes zero within the range of each deflection voltage applied to each of the plurality of electrodes, and changes the quadrant of the deflection offset based on the origin of the deflection voltage where the total deflection voltage becomes zero at a predetermined timing or based on the drift amount of the charged particle beam. Brief explanation of the drawing

[0011] FIG. 1 is a schematic diagram of a multi-charged particle beam drawing device according to an embodiment of the present invention. Figure 2 is a schematic diagram of a molded aperture array substrate. Figure 3 is a cross-sectional view of the second objective lens. Figures 4(a) and 4(b) are diagrams illustrating the orbits of secondary electrons according to a comparative example. Figure 5 is a diagram illustrating the possible range of bias and the drawing bias area. Figures 6(a) and 6(b) are diagrams illustrating the orbits of secondary electrons. Figures 7(a) to 7(d) are diagrams illustrating the locations of drawing deflection regions where the polarity of the deflection voltage is constant. Figure 8 is a diagram showing an example of the configuration of a positioning deflector. Figures 9(a) and 9(b) are drawings showing examples of the configuration of a positioning deflector. Figures 10(a) to 10(c) are diagrams illustrating the location of a drawing deflection region where the polarity of the deflection voltage is constant. Figures 11(a) and 11(b) are diagrams illustrating the location of a drawing deflection region where the polarity of the deflection voltage is constant. FIG. 12 is a drawing showing an example of a change in the offsetable area where the drawing bias area is located. FIG. 13 is a flowchart illustrating a drawing method according to the same embodiment. Figure 14 is a diagram illustrating the configuration of the positioning deflector and the applied voltage to each electrode. Specific details for implementing the invention

[0012] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0013] In the embodiments, a configuration using an electron beam is 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.

[0014] The drawing device illustrated in FIG. 1 comprises a drawing unit (10) that draws a desired pattern by irradiating an object, such as a mask or wafer, with an electron beam, and a control unit (60) that controls the operation of the drawing unit (10). The drawing unit (10) has an electron optical tube (12) and a drawing chamber (40). In this embodiment, a configuration using a multi-beam drawing device is described as an example of a drawing device.

[0015] Inside the electron optical tube (12), an electron source (14), an illumination lens (16), a molding aperture array substrate (18), a blanking aperture array substrate (20), a projection lens (22), a stopping aperture (limiting aperture member) (24), a first objective lens (26), a positioning deflector (28), a second objective lens (30), and a focus correction lens (32) are arranged. Inside the drawing chamber (40), an XY stage (42) is arranged. A mask blank, which is a substrate (44) to be drawn, is loaded on the XY stage (42).

[0016] The substrate (44) includes, for example, a wafer, or a reduction projection type exposure device such as a stepper or scanner using an excimer laser as a light source, or an extreme ultraviolet exposure device, to transfer a pattern onto the wafer using an exposure mask. Additionally, the substrate (44) includes a mask on which a pattern has already been formed. For example, since a Levenson type mask requires two exposures, a second pattern may be applied to a mask that has been processed once.

[0017] As illustrated in FIG. 2, the molded aperture array substrate (18) has openings (first openings) (18A) formed at a predetermined array pitch, with a vertical column of m × a horizontal column of n (m, n≥2). Each opening (18A) is formed, for example, as a rectangle with all the same dimensions. The shape of the openings (18A) may also be circular. A multi-beam MB is formed by a portion of the electron beam B passing through each of these multiple openings (18A).

[0018] A blanking aperture array substrate (20) is provided below a molded aperture array substrate (18), and a through hole (20A) (second opening) corresponding to each opening (18A) of the molded aperture array substrate (18) is formed. In each through hole (20A), a blanker (not shown) consisting of a pair of two electrodes is disposed. One side of the blanker is fixed at a ground potential, and the other side is switched to a potential different from the ground potential. The electron beam passing through each through hole (20A) is deflected independently by the voltage applied to the blanker. In this way, a plurality of blankers perform blanking deflection of each corresponding beam among the multi-beam MBs that have passed through the plurality of openings (18A) of the molded aperture array substrate (18).

[0019] The stopping aperture (24) shields the beam deflected by the blanker. The beam not deflected by the blanker passes through the opening (24A) (third opening) formed in the center of the stopping aperture (24). The stopping aperture (24) is positioned on the image plane of the crossover (on the light source) where the beam width is reduced, in order to reduce beam leakage during individual blanking by the blanking aperture array substrate (20).

[0020] The control unit (60) has a control calculator (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 blanker or the positioning deflector (28) provided 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 a Z sensor (not shown) and performs focus correction (dynamic focus).

[0021] The electron beam B emitted from the electron source (14) (emission unit) illuminates the entire molded aperture array substrate (18) nearly vertically by the illumination lens (16). As the electron beam B passes through a plurality of apertures (18A) of the molded aperture array substrate (18), a multi-beam MB consisting of a plurality of electron beams is formed. The multi-beam MB passes through each corresponding blanker of the blanking aperture array (20).

[0022] The multi-beam MB passing through the blanking aperture array substrate (20) is reduced by the projection lens (22) and proceeds toward the opening (24A) at the center of the stopping aperture (24). Here, the electron beam deflected by the blanker of the blanking aperture array substrate (20) is deviated from the opening (24A) of the stopping aperture (24) and is shielded by the stopping aperture (24). Meanwhile, the electron beam not deflected by the blanker passes through the opening (24A) of the stopping aperture (24). Blanking control is performed by turning the blanker on / off, and the beam's on / off is controlled.

[0023] In this way, the stopping aperture (24) shields each beam deflected to the beam OFF state by the blanker of the blanking aperture array substrate (20).

[0024] The multi-beam MB that passes through the stopping aperture (24) is focused by the first objective lens (26), the second objective lens (30), and the focus correction lens (32), and becomes a pattern image of the desired reduction ratio, and is projected onto the substrate (44).

[0025] A positioning deflector (28) positioned between the first objective lens (26) and the second objective lens (30) deflects and irradiates a multi-beam MB to a desired position on a substrate (44) loaded on a continuously moving XY stage (42). The positioning deflector (28) has multiple electrodes, and for example, a 4-pole deflector with 4 electrodes or an 8-pole deflector with 8 electrodes can be used. By changing the applied voltage to each electrode of the positioning deflector (28), the beam deflection position (the beam irradiation position on the substrate (44)) can be changed.

[0026] Since the dimensions of the multi-beam MB irradiated onto the substrate (44) are wide, such as a square with sides of 100 μm, even if the dimensions of the area (drawing deflection area) that the positioning deflector (28) must deflect is narrow compared to the dimensions of the beam array of the multi-beam MB, no problem with the drawing throughput occurs. For example, the dimensions of the drawing deflection area are sufficient to be a square with sides of several μm or a square with sides of 10 μm.

[0027] The focus correction lens (32) is positioned downstream of the multi-beam MB's direction of travel, rather than the positioning deflector (28).

[0028] For the illumination lens (16), projection lens (22), first objective lens (26), and second objective lens (30), an electronic lens (magnetic field type lens) is used, but it is acceptable to use electrostatic lenses for some or all of them. The focus correction lens (32) performs dynamic focus adjustment for height fluctuations on the surface of the substrate (44), and while an electrostatic lens is used, an electronic lens (including a coil that generates an axis-symmetric magnetic field) may also be used. Additionally, it may be configured as a multi-stage lens system in which each applied voltage or excitation current changes in a constant relationship. Alternatively, the second objective lens (30) may be equipped with the function of the focus correction lens (32), or the second objective lens (30) and the focus correction lens (32) may be configured to perform focus adjustment by linking in a constant relationship.

[0029] The second objective lens (30) is an electronic lens and, as shown in FIG. 3, has a coil (30a) and a yoke (30b) that accommodates the coil (30a). The yoke (30b) is made of a material with high permeability such as iron and has a cutout (pole piece (30c)) in part.

[0030] The magnetic field lines created by flowing current through the coil (30a) leak into space through the pole piece (30c) to create a magnetic field.

[0031] The focus correction lens (32) is positioned, for example, inside the second objective lens (30), for example, at the height of the pole piece (30c). The focus correction lens (32) is an electrostatic lens and has a ring-shaped electrode. A positive voltage is applied to the surface of the substrate to this electrode, and the focus correction lens (32) is operated in a positive voltage range with respect to the surface of the substrate.

[0032] When a multi-beam MB (primary beam) is irradiated onto a substrate (44), secondary electrons are emitted from the substrate surface. By operating the focus correction lens (32) in a positive voltage range, the secondary electrons are guided upward from the substrate surface and travel upward within the electron optical barrel (12). By suppressing the secondary electrons from returning to the substrate surface, positional changes caused by charging of the resist can be suppressed.

[0033] In the drawing process, the resist on the surface of the substrate (44) may evaporate due to beam irradiation, and contamination may adhere to the surface of a plurality of electrodes of the positioning deflector (28). Secondary electrons traveling upward within the electron optical tube (12) may reach the contamination on the electrode surface of the positioning deflector (28), become charged, and change the trajectory of the multi-beam MB.

[0034] In a conventional drawing device, in the operation of changing the beam deflection position (the beam irradiation position on the substrate (44)), as illustrated in FIG. 4(a) and FIG. 4(b), the polarity of the deflection voltage applied to each electrode of the position determining deflection device (28) was frequently changed. When the polarity of the deflection voltage changes, the electric field strength and direction within the position determining deflection device (28) change significantly, and the arrival position of secondary electrons, i.e., the charging position, changes significantly across the electrodes. As the charging position changes significantly, a large change in the electric field near the beam occurs, and as a result, a large beam irradiation position variation (drift) occurs.

[0035] Accordingly, in this embodiment, by applying an offset (deflection offset) to the deflection position of the position determining deflector (28), that is, by shifting the deflection position, the secondary electron is removed from near the center of the beam and the secondary electron is moved in a nearly constant direction in the transverse direction. As a result, the secondary electron reaches a limited area on the surface of the deflector, etc.

[0036] For example, as shown in FIG. 5, the drawing deflection region R1 is shifted within a deflectionable range R0 so as not to include the origin of the deflection voltage, that is, the state where the deflection voltage of any electrode of the positioning deflectioner (28) becomes 0 (which deflection voltage is 0) within the drawing deflection region R1. Here, the deflectionable range R0 is the range in which the positioning deflectioner (28) can be deflected to the maximum output of the deflection amplifier included in the deflection control circuit (64). The drawing deflection region R1 is a deflection region required for the drawing process. By not including the origin of the deflection voltage within the drawing deflection region R1, as shown in FIG. 6 (a) and FIG. 6 (b), the change in the arrival position of the secondary electron, that is, the charge position, with respect to the change in the deflection position is suppressed, and thus the beam irradiation position variation (drift) is suppressed.

[0037] In addition, it is more effective to set the deflection offset so that the polarity of the deflection voltage of each electrode (individual electrode) of the positioning deflectioner (28) remains constant and does not change. In order to make the polarity of the deflection voltage of each electrode constant, in the case of a 4-pole deflectioner, the drawing deflection area R1 can be placed into any of the offsetable areas R11 to R14 shown in FIG. 7 (a) to FIG. 7 (d). As a result, the area where secondary electrons come into contact with the deflection electrode is more limited, and thus the range of the location where charging occurs is also more limited. As a result, changes in the electric field strength and direction within the positioning deflectioner (28) are suppressed, beam irradiation position fluctuation (drift) is suppressed, and beam position precision is improved.

[0038] In addition, “setting a bias offset so that the polarity of the bias voltage of each electrode becomes constant” and automatically (necessarily) “not including a state where any bias voltage becomes zero” are satisfied. Therefore, “polarity becomes constant” is a more restrictive condition than “no bias voltage includes zero”.

[0039] In addition, the condition regarding the voltage applied to the deflector contributes more directly to drift reduction. However, as a result, the beam deflection position or deflection area on the substrate surface shifts, and it cannot be said that the beam deflection position or deflection area on the substrate surface itself directly contributes to drift reduction.

[0040] FIG. 8 shows an example of the configuration of a positioning deflector (28). In the example shown in FIG. 8, the positioning deflector (28) is an electrostatic 4-pole deflector having four electrodes (28a to 28d). When the deflection offset is (X0, Y0), the deflection amount for pattern drawing based on the pattern position of the drawing data is (X, Y), and the deflection sensitivity coefficient is k, the deflection voltages V1 to V4 applied to the electrodes (28a to 28d) are as follows.

[0041]

[0042] The possible range of bias in the x direction is -X M To X M , the possible range of bias in the y-direction is -Y M to Y M , the drawing bias region in the x direction is -X W To X W , the drawing bias region in the y direction -Y W to Y W Consider the case where it is done in this way. As shown in FIG. 5, the deflection offset (X0, Y0) for not including the origin of the deflection voltage within the drawing deflection region R1 and for the polarity of the deflection voltage of each electrode of the positioning deflectioner (28) to be constant must satisfy the following condition equation.

[0043]

[0044] A bias offset (X0, Y0) that satisfies the above conditional equation is calculated in advance and stored in the memory (not shown) of the control unit (60).

[0045] When processing the drawing, the control calculator (62) reads the drawing data from the memory device and performs a multi-stage data conversion process to generate the device's unique shot data. The shot data defines the irradiation amount and irradiation position coordinates for each shot. The irradiation position coordinates are calculated using the aforementioned deflection offset (X0, Y0) as the origin of the deflection.

[0046] The control calculator (62) outputs the irradiation amount of each shot to the deflection control circuit (64) based on the shot data. The deflection control circuit (64) calculates the irradiation time t by dividing the input irradiation amount by the current density. Then, when performing the corresponding shot, the deflection control circuit (64) applies a deflection voltage to the corresponding blanker of the blanking aperture array substrate (20) so that the blanker beam ON for the irradiation time t.

[0047] Additionally, the deflection control circuit (64) calculates a drawing deflection amount (X, Y) so that a beam is irradiated at an irradiation position indicated by shot data, adds or subtracts a deflection offset (X0, Y0) to this, and applies the deflection voltage V1 to V4, which is multiplied by a deflection sensitivity coefficient k, to each electrode (28a to 28d) of the position determining deflection device (28). Additionally, when calculating the drawing deflection amount, position information of the XY stage (42) is obtained from a position measuring device (not shown), such as a laser measuring device, and used.

[0048] In this way, by making the polarity of the deflection voltage of each deflection electrode of the positioning deflectioner (28) constant, secondary electrons are guided to a limited area of ​​the positioning deflectioner (28), and by suppressing changes in the deflectioner charge, the beam can be stabilized.

[0049] The positioning deflector (28) may use an 8-pole deflector having 8 electrodes (28a to 28h) as shown in FIG. 9 (a) and FIG. 9 (b). The deflectors shown in FIG. 9 (a) and FIG. 9 (b) differ in their installation angle by 22.5 degrees. In this specification, the arrangement in which the deflection coordinate axis passes through the center of the gap of the deflection electrode as in FIG. 9 (a) is referred to as a 22.5-degree rotation arrangement, and the arrangement in which the deflection coordinate axis passes through the center of the deflection electrode as in FIG. 9 (b) is referred to as a 0-degree rotation arrangement.

[0050] In the 22.5-degree rotation arrangement shown in FIG. 9(a), the deflection voltages V1 to V8 applied to the electrodes (28a to 28h) are expressed as follows using a deflection offset (X0, Y0), a drawing deflection amount (X, Y), and a deflection sensitivity coefficient k.

[0051]

[0052] In order for the polarity of the deflection voltage of each electrode of the positioning deflector (28) to be constant in the 22.5-degree rotation arrangement, the drawing deflection area may be placed in any of the following: the offsetable area Ra (Ra1 to Ra4) at intervals of 90 degrees from 22.5 degrees to 67.5 degrees as shown in FIG. 10 (a), the offsetable area Rb (Rb1, Rb2) at intervals of -22.5 degrees to 22.5 degrees as shown in FIG. 10 (b) and rotated 180 degrees from there, or the offsetable area Rc (Rc1, Rc2) at intervals of 180 degrees from 67.5 degrees to 112.5 degrees as shown in FIG. 10c.

[0053] In order for the drawing bias region to be included in any of the offsetable regions Ra1 to Ra4, the bias offset (X0, Y0) must satisfy the following condition equation.

[0054]

[0055] For the drawing bias region to be included in the offsetable region Rb1 or Rb2, the bias offset (X0, Y0) must satisfy the following condition.

[0056]

[0057] For the drawing bias region to be included in the offsetable region Rc1 or Rc2, the bias offset (X0, Y0) must satisfy the following condition.

[0058]

[0059] In the 0-degree rotation arrangement shown in FIG. 9(b), the deflection voltages V1 to V8 applied to the electrodes (28a to 28h) are expressed as follows using a deflection offset (X0, Y0), a drawing deflection amount (X, Y), and a deflection sensitivity coefficient k'.

[0060]

[0061] In order for the polarity of the deflection voltage of each electrode of the positioning deflector (28) to be constant in the 0-degree rotation arrangement, the drawing deflection area may be placed in either the offsetable area Rd (Rd1 to Rd4) which is symmetric with respect to the x-axis, y-axis, and origin as shown in FIG. 11 (a), or the offsetable area Re (Re1 to Re4) which is symmetric with respect to the x-axis, y-axis, and origin as shown in FIG. 11 (b).

[0062] In order for a drawing bias region to be included in any of the offsetable regions Rd1 to Rd4, the bias offset (X0, Y0) must satisfy the following conditional equation.

[0063]

[0064] In order for the drawing bias region to be included in the offsetable region Re1 to Re4, the bias offset (X0, Y0) must satisfy the following conditional equation.

[0065]

[0066] Maintaining a constant deflection offset during the drawing process is effective for reducing drift. However, if, for example, contamination already exists in the direction of the deflection offset, keeping the offset constant may cause the contamination to grow significantly, altering the beam's trajectory and potentially leading to large drift.

[0067] Accordingly, in the present embodiment, during the drawing process, drift measurement is performed at predetermined time intervals, and when the amount of drift exceeds a predetermined threshold value, the quadrant (and size) of the bias offset is changed, and the offsetable region where the drawing bias region is located is changed to another offsetable region. For example, as shown in FIG. 12, the offsetable region where the drawing bias region R1 is located is changed from the offsetable region Ra1 to the offsetable region Ra4. By doing so, the growth of contamination can be suppressed and the drift reduced.

[0068] Here, changing the quadrant of the deflection offset means moving the center position of the drawing deflection region to another quadrant (a position where the polarity of at least one of X and Y is changed) in the circumferential direction centered on the origin of the deflection voltage (see FIG. 5). In addition, changing the magnitude of the deflection offset means increasing or decreasing the distance between the center position of the drawing deflection region and the origin of the deflection voltage.

[0069] A drawing method according to the present embodiment is described following the flowchart shown in FIG. 13. A new positioning deflector (28) is mounted on the drawing device, and a deflection offset is set (steps S1, S2). For example, as shown in FIG. 9 (a), an 8-pole deflector is rotated 22.5 degrees, and a deflection offset is set so that the drawing deflection area enters the offsetable area Ra1 shown in FIG. 10 (a).

[0070] A beam is irradiated onto a substrate (44) to draw a pattern (step S3). The irradiation position coordinates are calculated using the deflection offset set in step S2 as the origin of the deflection, the deflection offset is added to or subtracted from the deflection amount for drawing, and a deflection voltage is applied to each electrode of the position determining deflection device (28).

[0071] The position determining deflector (28) is used continuously until the usage time exceeds a predetermined value (Step S4: No), and when the time for exchange is reached after using it for a predetermined time (Step S4: Yes), it is exchanged (Step S5).

[0072] While the drawing process is being performed using the positioning deflector (28), the drawing process is stopped at a predetermined timing, and drift measurement is performed (Step S6: e.g., Step S7). The method of drift measurement is not limited, and known methods may be used. For example, only a specific beam (or a beam group including multiple beams) among the multi-beams is turned on, a mark (not shown) on the XY stage (42) is scanned with the beam, and reflected electrons are detected by a detector (not shown). A control calculator (62) calculates the beam position from the waveform of the detected amount of reflected electrons and the stage position, and calculates the amount of drift from the difference between the calculated beam position and the abnormal value. Instead of a reflective mark, a transmissive mark may be used, the transmissive mark is scanned, and the beam passing through the opening of the transmissive mark is detected, and the beam position may be calculated from the waveform of the detected amount of electrons and the stage position.

[0073] If the amount of drift is less than a predetermined value (Step S8: No), pattern drawing continues without changing the bias offset.

[0074] If the amount of drift is greater than a predetermined value (Step S8: Yes), since it is believed that contamination is growing significantly in the quadrant of the current bias offset, the quadrant of the bias offset is changed, and the offsetable area where the drawing bias area is located is changed to another offsetable area (Step S9). For example, as shown in FIG. 12, the offsetable area where the drawing bias area R1 is located (entered) is changed from offsetable area Ra1 to offsetable area Ra4. The bias offset after the change is set, and the drawing process is resumed (Step S3).

[0075] In this way, according to the present embodiment, since the focus correction lens (32) is operated in a positive voltage range with respect to the substrate surface, secondary electrons can be guided upward from the substrate surface and the spatial retention of secondary electrons can be suppressed. In addition, by setting a deflection offset so as not to include a state where the deflection voltage of any electrode of the positioning deflectioner (28) becomes zero, the drawing deflection area is shifted, and when the amount of drift increases, the quadrant (and size) of the deflection offset is changed to change the offsetable area where the drawing deflection area is located, thereby suppressing fluctuations in the beam position caused by the charging of the deflectioner electrodes and improving the drawing precision.

[0076] In step S9 of FIG. 13, the change location (quadrant of the change location) of the offsetable area where the drawing bias area is located may be selected randomly, or the amount of drift in each offsetable area may be measured and the optimal offsetable area where the amount of drift is minimized may be selected. For example, when changing the offsetable area where the drawing bias area is located from the offsetable area Ra1 of FIG. 10 (a) to any of the other offsetable areas Ra2 to Ra4, drift measurement is performed while the drawing bias area is located in each of the offsetable areas Ra2 to Ra4, and the offsetable area where the amount of drift is minimized is selected.

[0077] The drift amount for each offsetable region is stored in memory (city omitted), and when changing the bias offset thereafter, the offsetable regions may be selected in order of smallest stored drift amount.

[0078] In the above embodiment, the quadrant of the bias offset is changed using a positioning biaser, but the quadrant of the bias offset may be changed using a biaser different from the positioning biaser.

[0079] In the above embodiment, an example was described in which the bias offset is changed when the measured drift amount exceeds a predetermined value, but the bias offset may also be changed when the drawing time or the number of drawing cycles (number of drawn substrates) reaches a predetermined value.

[0080] In the above embodiment, an example was described in which the offsetable area where the drawing bias area is located is changed by changing the bias offset, but the drawing bias area may be moved within the same offsetable area.

[0081] As illustrated in FIG. 14, a positive common voltage Vc with respect to the substrate surface may be added to the applied voltage for each electrode of the positioning deflector (28). This common voltage Vc is the defined voltage V applied to the focus correction lens (32). F It is desirable to set the value to be greater than or equal to the upper limit value. By doing so, in order for the secondary electrons passing through the focus correction lens (32) to move to the position determining deflector (28) without decelerating, the retention of secondary electrons between the focus correction lens (32) and the position determining deflector (28) can be prevented, thereby improving the beam irradiation position accuracy.

[0082] In the above embodiment, a drawing device using a multi-beam was described, but the drawing method can also be applied to a drawing device using a single beam.

[0083] Furthermore, the present invention is not limited to the above embodiments, but can be embodied by modifying the components during the implementation phase without departing from the gist thereof. Additionally, various inventions can be formed by appropriate combinations of a plurality of components disclosed in the above embodiments. For example, some components may be deleted from the entire set of components disclosed in the embodiments. Furthermore, components spanning different embodiments may be appropriately combined. Explanation of the symbols

[0084] 10: Drawing Department 12: Electro-optical barrel 14: Electron gun 16: Lighting lens 18: Molded Aperture Array Substrate 20: Blanking Aperture Array Board 22: Projection lens 24: Stopping Aperture 26: First objective lens 28: Position determination biaser 30: Second objective lens 32: Focus correction lens 40: Drawing Room 42: XY Stage 44: Substrate 60: Control unit

Claims

Claim 1 A charged particle beam drawing method comprising: a process of deflecting a charged particle beam to a position with a deflection offset added such that the range of each deflection voltage applied to each of a plurality of electrodes of an electrostatic positioning deflector does not include a state in which any of the deflection voltages becomes zero; a process of irradiating the charged particle beam onto a substrate; and a process of changing the quadrant of the deflection offset based on the origin of the deflection voltage at which the total deflection voltage becomes zero at a predetermined timing or based on the drift amount of the charged particle beam. Claim 2 A method for drawing a charged particle beam according to claim 1, wherein the charged particle beam is deflected at a position where the voltage polarity of each electrode is added so as not to fluctuate within the range of each deflection voltage, wherein the deflection offset is added. Claim 3 A method for drawing a charged particle beam according to claim 1, wherein the amount of drift of the charged particle beam is measured, and the quadrant of the deflection offset is changed when the amount of drift exceeds a threshold value. Claim 4 A charged particle beam drawing method according to paragraph 3, wherein when the amount of drift exceeds a threshold value, the quadrant and magnitude of the bias offset are changed. Claim 5 A charged particle beam drawing method according to paragraph 3, wherein the change point of the quadrant of the bias offset is randomly selected. Claim 6 A charged particle beam drawing method according to claim 3, wherein the change of the quadrant of the bias offset and the measurement of the drift amount are performed multiple times, and the quadrant where the drift amount is minimized is selected as the change point. Claim 7 A method for drawing a charged particle beam according to claim 1, wherein a focus correction lens positioned downstream of the direction of travel of the charged particle beam is operated in a defined voltage range. Claim 8 A charged particle beam drawing method according to claim 7, wherein a common voltage greater than or equal to the upper limit of the voltage applied to the focus correction lens is added to the voltage applied to each of the plurality of electrodes of the position determining deflector. Claim 9 A charged particle beam drawing device comprising: an electrostatic positioning deflector having a plurality of electrodes and deflecting a charged particle beam irradiated onto a substrate of a drawing target; and a deflection control circuit that deflects the charged particle beam at a position where a deflection offset is added so as not to include a state where the deflection voltage of any of the electrodes becomes zero within the range of each deflection voltage applied to each of the plurality of electrodes, and changes the quadrant of the deflection offset based on the origin of the deflection voltage where the total deflection voltage becomes zero at a predetermined timing or based on the drift amount of the charged particle beam. Claim 10 In claim 9, the deflection control circuit deflects the charged particle beam to a position at which the deflection offset is added, so that the voltage polarity of each electrode does not fluctuate within the range of each deflection voltage, in a charged particle beam drawing device. Claim 11 In claim 9, the bias control circuit measures the amount of drift of the charged particle beam and changes the quadrant of the bias offset when the amount of drift exceeds a threshold value, a charged particle beam drawing device. Claim 12 In claim 11, the above-described bias control circuit changes the quadrant and magnitude of the bias offset when the amount of drift exceeds a threshold value, in a charged particle beam drawing device. Claim 13 In claim 11, the above-described bias control circuit randomly selects a change point of the quadrant of the bias offset, a charged particle beam drawing device. Claim 14 In claim 11, the bias control circuit performs a change of the quadrant of the bias offset and a measurement of the drift amount multiple times, and selects the quadrant where the drift amount is minimized as the change point, a charged particle beam drawing device. Claim 15 In claim 9, the deflection control circuit operates a focus correction lens positioned downstream of the direction of travel of the charged particle beam from the position determining deflector in a defined voltage range, in a charged particle beam drawing device. Claim 16 In claim 15, the deflection control circuit adds a common voltage greater than or equal to the upper limit of the voltage applied to the focus correction lens to the voltage applied to each of the plurality of electrodes of the position determining deflector, a charged particle beam drawing device.

Images