Electron beam drawing method, electron beam drawing device, and program

Abstract

PURPOSE: To provide a method capable of correcting a position deviation of a beam irradiation position and a pattern formation position due to deformation of an irreversible sample by an irradiation of an electron beam.CONSTITUTION: An electron beam drawing method of an embodiment of the present invention, comprises: a step of calculating a first position deviation amount from a position on a design of a pattern generated by an irreversible deformation of a sample after a termination of a drawing processing in the case of drawing the pattern by irradiating the electron beam to the sample irreversibly deformed while depending on an irradiation amount distribution of the electron beam; a step of calculating a correction amount for correcting a position of the pattern when forming the pattern by irradiating the electron beam to the sample or an irradiation position of the electron beam on the basis of the first position deviation amount; and a step of performing the drawing processing for drawing the pattern to the sample on the basis of the correction amount.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] One aspect of the present invention relates to an electron beam lithography method, an electron beam lithography apparatus, and a program, and, for example, to a technique for lithography while correcting positional deviation on a substrate that is irreversibly deformed by irradiation with an electron beam. [Background technology]

[0002] Lithography technology, which is responsible for the advancement of miniaturization of semiconductor devices, is an extremely important process in semiconductor manufacturing that is the only one that generates patterns. In recent years, with the increasing integration of LSIs, the circuit line width required for semiconductor devices has become finer year by year. Here, electron beam (electron beam) drawing technology has inherently excellent resolution, and drawing on wafers and the like is carried out using electron beams.

[0003] For example, there is a lithography device that uses multiple beams. Compared to lithography using a single electron beam, the use of multiple beams allows many beams to be irradiated at once, greatly improving throughput. In such a lithography device using the multi-beam method, for example, an electron beam emitted from an electron gun is passed through a mask with multiple holes to form multiple beams, each of which is blanked, and each beam that is not blocked is reduced in size by an optical system and deflected by a deflector to be irradiated at a desired position on a sample.

[0004] With the widespread use of multi-patterning, PSM masks, EUV masks, and the like, the demand for global pattern position accuracy within a mask is becoming stricter year by year.

[0005] One of the factors that deteriorates the global pattern position accuracy is that the glass substrate used for the sample undergoes reversible deformation due to thermal expansion caused by heating of the glass substrate accompanied by irradiation with an electron beam and subsequent contraction. The deformation of the glass substrate causes a problem of misalignment of the beam irradiation position or the pattern formation position. To address this problem, a technology has been disclosed that calculates the distortion caused by deformation of the substrate due to thermal expansion accompanied by bulk heating and offsets the pattern position (see Patent Document 1).

[0006] On the other hand, to address this issue, blank manufacturers of glass substrates have developed low-thermal expansion substrates (LTEM: low-thermal expansion material substrates) that suppress the thermal expansion of the substrate itself. In such LTEM substrates, the thermal expansion caused by the temperature rise associated with the irradiation of the electron beam is small, and the deformation of the substrate caused by this can be suppressed. This has solved problems such as misalignment due to reversible deformation associated with thermal expansion. However, it has been found that the irradiation of the electron beam causes an irreversible shrinkage phenomenon of the glass substrate. This is due to the fact that the beam irradiation amount has increased by lowering the resist sensitivity to improve local dimensional accuracy, and that the spread of LTEM substrates has made it possible to ignore thermal expansion, and the shrinkage phenomenon of the glass substrate has become relatively apparent. The deformation due to the irreversible shrinkage phenomenon of the glass substrate has caused problems such as deterioration of the global positional accuracy of the beam irradiation position and the pattern formation position. This problem is a problem in both multi-beam writing and single-beam writing. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-312030 A Summary of the Invention [Problem to be solved by the invention]

[0008] One aspect of the present invention provides a method and apparatus capable of correcting positional deviations of a beam irradiation position or a pattern formation position caused by irreversible deformation of a sample due to irradiation with an electron beam. [Means for solving the problem]

[0009] An electron beam lithography method according to one aspect of the present invention includes the steps of: a step of calculating a first positional deviation amount from a design position of a pattern caused by irreversible deformation of a sample after completion of a writing process when the sample is irradiated with an electron beam and a pattern is written thereon; calculating a correction amount for correcting a pattern position or an irradiation position of the electron beam when forming a pattern by irradiating the sample with the electron beam based on the first positional deviation amount; performing a writing process of writing the pattern on a sample based on the correction amount; The present invention is characterized by comprising:

[0010] The above-mentioned writing process further includes a step of calculating a second positional deviation amount from a design position of the pattern caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample before the irradiation time of the electron beam, It is preferable to perform the correction based on the difference between the second positional deviation amount and the first positional deviation amount.

[0011] Moreover, the drawing process includes a first drawing process for drawing the first chip pattern, and a second drawing process that is performed after the first drawing process and for drawing the second chip pattern so as to overlap the first chip pattern, The first positional deviation amount is preferably a positional deviation amount from a designed position of the pattern due to irreversible deformation of the sample after completion of the second writing process.

[0012] and calculating a second positional deviation amount from a designed position at a time point of irradiation of the electron beam, the second positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated onto the sample prior to the time point of irradiation in the first writing process. calculating a third positional deviation amount from a designed position at a time point of irradiation of the electron beam in the second writing process, the third positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated onto the sample prior to the time point of irradiation; Further equipped with The step of calculating the correction amount includes: calculating a first correction amount in the first drawing process based on a difference between the second positional deviation amount and the first positional deviation amount; calculating a second correction amount in the second drawing process based on a difference between the third positional deviation amount and the first positional deviation amount; It is preferable to have the following.

[0013] In addition, alignment marks are formed on the sample in advance, The sample is placed on a movable stage, measuring a first mark position of the mark before the first writing process; calculating a positional deviation of the mark position from the first mark position due to irreversible deformation of the sample after completion of the first writing process; measuring a second mark position of the mark before the start of the second writing process in a state in which the sample is once removed from the stage and is placed on the stage again for the second writing process; calculating a third mark position by correcting the second mark position by an amount of positional deviation of the mark position from the second mark position before starting the second writing process; Equipped with a position of a first chip pattern to be written on the sample in the first writing process is defined based on a first mark position; It is preferable that the position of the second chip pattern drawn on the sample in the second drawing process is defined with reference to the third mark position.

[0014] An electron beam lithography apparatus according to one aspect of the present invention comprises: a stage for mounting a sample that is deformed irreversibly depending on the distribution of the dose of the electron beam; a first positional deviation amount calculation unit that calculates a first positional deviation amount from a designed position of a pattern caused by irreversible deformation of the sample after completion of writing of the pattern on the sample using an electron beam; a correction amount calculation unit that calculates a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the sample is irradiated with the electron beam based on the first positional deviation amount; a writing mechanism for writing the pattern on a sample based on the correction amount; The present invention is characterized by comprising:

[0015] A program according to one aspect of the present invention comprises: a function of calculating a first positional deviation amount from a design position of a pattern caused by irreversible deformation of a sample after completion of a writing process when a pattern is written by irradiating the sample with an electron beam, the sample being irreversibly deformed depending on a distribution of an irradiation amount of the electron beam; a function of storing the first position deviation amount in a storage device; a function of reading out a first positional deviation amount from the storage device, and calculating, based on the first positional deviation amount, a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the electron beam onto a sample; to be executed by the computer.

[0016] Another aspect of the present invention is an electron beam writing method, a step of calculating a first positional deviation amount from a designed position of the first chip pattern at a time point of irradiation of the electron beam, the first positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample before the time point of irradiation of the electron beam, in a first writing process for writing a first chip pattern when a pattern is written by irradiating the electron beam to the sample which irreversibly deforms depending on an irradiation amount distribution of the electron beam; a step of calculating a second positional deviation amount from a designed position of the second chip pattern at a time point of irradiation with the electron beam, the second positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated onto the sample prior to the time point of irradiation in a second writing process for writing the second chip pattern so as to overlap the first chip pattern; calculating a correction amount for correcting a pattern position or an irradiation position of the electron beam when the pattern is formed by irradiating the electron beam onto a sample in a second writing process, based on a difference between the second positional deviation amount and the first positional deviation amount; performing a first writing process for writing a first chip pattern on a sample and a second writing process for writing a second chip pattern on the sample based on the correction amount; The present invention is characterized by comprising:

[0017] Another aspect of the present invention is an electron beam lithography apparatus, a stage for mounting a sample that is deformed irreversibly depending on the distribution of the dose of the electron beam; a positional deviation amount calculation unit that calculates a first positional deviation amount from a designed position of the first chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample before the irradiation time of the electron beam, at a first writing process for writing a first chip pattern when a pattern is written by irradiating the electron beam to a sample, and calculates a second positional deviation amount from a designed position of the second chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample before the irradiation time, at a time of irradiation of the electron beam, at a second writing process for writing a second chip pattern so as to overlap the first chip pattern; a correction amount calculation unit that calculates a correction amount for correcting a pattern position or an irradiation position of the electron beam when the pattern is formed by irradiating the electron beam onto a sample in a second writing process, based on a difference between the second positional deviation amount and the first positional deviation amount; a writing mechanism that performs a first writing process for writing a first chip pattern on a sample and a second writing process for writing a second chip pattern on the sample based on the correction amount; The present invention is characterized by comprising:

[0018] A program according to another aspect of the present invention comprises: a function of calculating a first positional deviation amount from a designed position of a first chip pattern at a time point of irradiation of the electron beam, the first positional deviation amount being caused by irreversible deformation of a sample caused by the electron beam irradiated to the sample prior to the time point of irradiation of the first chip pattern, in a first writing process for writing a first chip pattern when a pattern is written by irradiating the sample with the electron beam on the sample which irreversibly deforms depending on a distribution of the amount of irradiation of the electron beam; a function of calculating, in a second writing process for writing a second chip pattern so as to overlap the first chip pattern, a second positional deviation amount from a designed position of the second chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample prior to the irradiation time of the electron beam, at the time of irradiation of the electron beam; a function of storing the first positional deviation amount and the second positional deviation amount in a storage device; a function of reading out the first positional deviation amount and the second positional deviation amount from the storage device, and calculating, based on a difference between the second positional deviation amount and the first positional deviation amount, a correction amount for correcting a pattern position or an irradiation position of the electron beam when the pattern is formed by irradiating the electron beam onto a sample in a second writing process; to be executed by the computer. Effect of the Invention

[0019] According to one aspect of the present invention, it is possible to correct positional deviations of the beam irradiation position or the pattern formation position caused by irreversible deformation of a sample due to irradiation with an electron beam. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a conceptual diagram showing a configuration of a drawing device in a first embodiment. [Diagram 2] 2 is a conceptual diagram showing a configuration of a shaping aperture array substrate in the first embodiment. FIG. [Diagram 3] 2 is a cross-sectional view showing a configuration of a blanking aperture array mechanism in the first embodiment. FIG. [Figure 4] FIG. 2 is a diagram showing an example of an evaluation board in the first embodiment. [Diagram 5]5 is a diagram showing an example of the relationship between the amount of positional misalignment of an evaluation substrate and an example of deformation of the substrate in the first embodiment. FIG. [Figure 6] 4 is a diagram showing an example of a state when an evaluation substrate is irradiated with a beam in the first embodiment. FIG. [Figure 7] 5A to 5C are diagrams showing an example of a stress state caused by beam irradiation on an evaluation substrate in the first embodiment. [Figure 8] 11 is a diagram showing an example of a state of misalignment on a substrate surface in a first comparative example of the first embodiment. FIG. [Figure 9] FIG. 11 is a diagram showing an example of deformation of a substrate surface in a first comparative example of the first embodiment. [Figure 10] 5A to 5C are diagrams showing an example of a state of misalignment on the substrate surface in the first embodiment. [Figure 11] FIG. 2 is a flow chart showing an example of main steps of the writing method according to the first embodiment. [Figure 12] FIG. 11 is a flowchart showing another example of the main steps of the writing method according to the first embodiment. [Figure 13] 5 is a diagram showing an example of the relationship between the reduction ratio of the substrate and the dose amount in the first embodiment. FIG. [Figure 14] FIG. 2 is a diagram showing an example of a model based on a finite element method in the first embodiment. [Figure 15] FIG. 2 is a conceptual diagram for explaining an example of a drawing operation in the first embodiment. [Figure 16] 3 is a diagram showing an example of a region irradiated with multiple beams and a pixel to be written in the first embodiment. FIG. [Figure 17] FIG. 2 is a diagram for explaining an example of a multi-beam writing operation in the first embodiment. [Figure 18] FIG. 11 is a conceptual diagram showing a configuration of a drawing device in the second embodiment. [Figure 19] FIG. 11 is a diagram for explaining a two-stroke drawing method in the second embodiment. [Figure 20] 13 is a diagram showing an example of a state of misalignment on a substrate surface in a comparative example of the second embodiment. FIG. [Figure 21]13A and 13B are diagrams showing an example of a state of misalignment on the substrate surface in the second embodiment. [Figure 22] FIG. 11 is a flow chart showing an example of main steps of a writing method according to the second embodiment. [Figure 23] 13A and 13B are diagrams showing an example of a state of misalignment on the substrate surface in the third embodiment. [Figure 24] FIG. 13 is a conceptual diagram showing a configuration of a drawing device in a fourth embodiment. [Diagram 25] FIG. 13 is a diagram showing an example of a state of misalignment on a substrate surface in a comparative example of the fourth embodiment. [Figure 26] 13 is a diagram showing an example of a state of misalignment on the substrate surface in the fourth embodiment. FIG. [Figure 27] FIG. 13 is a flow chart showing an example of some of the main steps of a writing method according to the fourth embodiment. [Figure 28] FIG. 13 is a flowchart showing the remaining steps of the example of the main steps of the writing method according to the fourth embodiment. [Figure 29] FIG. 13 is a diagram showing an example of a sample surface on which an alignment mark is formed in the fourth embodiment. [Diagram 30] FIG. 13 is a diagram showing an example of a mark position after a first drawing process in the fourth embodiment. [Diagram 31] FIG. 13 is a diagram showing an example of a mark position after a second drawing process in the fourth embodiment. [Diagram 32] 13A and 13B are diagrams showing an example of a state of misalignment on the substrate surface in the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In the following, in the embodiment, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and may be a beam using charged particles such as an ion beam. In addition, in the embodiment, a case where a multi-beam consisting of a plurality of electron beams is used will be described. However, the correction method described below is not limited to a multi-beam, and can also be applied to a case where a single beam is used.

[0022] Embodiment 1 FIG. 1 is a conceptual diagram showing a configuration of a drawing apparatus in the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing mechanism 150 and a control circuit 160. The drawing apparatus 100 is an example of a multi-charged particle beam drawing apparatus and an example of a multi-charged particle beam exposure apparatus. The drawing mechanism 150 includes an electron lens barrel 102 (electron beam column) and a drawing chamber 103. In the electron lens barrel 102, an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a deflector 208, and a deflector 209 are arranged.

[0023] An XY stage 105 is placed in the drawing chamber 103. A sample 101, such as a mask that will be a drawing target substrate during drawing (exposure) is placed on the XY stage 105. The sample 101 includes an exposure mask used in manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured. The sample 101 also includes a mask blank on which a resist is applied and on which nothing is yet drawn. A low thermal expansion (LTEM) substrate is used as the glass substrate of the sample 101.

[0024] Furthermore, a mirror 210 for measuring the position of the XY stage 105 is also disposed on the XY stage 105 .

[0025] The control system circuit 160 includes a control computer 110, a memory 112, a deflection control circuit 130, digital-to-analog conversion (DAC) amplifier units 132 and 134, a lens control circuit 136, a stage control mechanism 138, a stage position measurement device 139, and storage devices 140 and 142 such as magnetic disk devices. The control computer 110, the memory 112, the deflection control circuit 130, the lens control circuit 136, the stage control mechanism 138, the stage position measurement device 139, and the storage devices 140 and 142 are connected to each other via a bus (not shown). The deflection control circuit 130 is connected to the DAC amplifier units 132 and 134 and a blanking aperture array mechanism 204. The deflector 209 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 132. The deflector 208 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 134. For example, an electromagnetic lens group, such as the illumination lens 202 , the reduction lens 205 , and the objective lens 207 , are controlled by a lens control circuit 136 .

[0026] The position of the XY stage 105 is controlled by driving motors for each axis (not shown) controlled by a stage control mechanism 138. A stage position measuring device 139 receives reflected light from a mirror 210 and measures the position of the XY stage 105 based on the principle of laser interference.

[0027] In the control computer 110, a dose map creating unit 50, a final positional deviation amount calculating unit 52, a positional deviation amount during writing calculating unit 54, a correction amount calculating unit 56, a correction amount map creating unit 58, a shot data generating unit 70, a data processing unit 72, a transfer processing unit 74, and a writing control unit 76 are arranged. Each of the "~ units" such as the dose map creating unit 50, the final positional deviation amount calculating unit 52, the positional deviation amount during writing calculating unit 54, a correction amount calculating unit 56, a correction amount map creating unit 58, the shot data generating unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76 has a processing circuit. Such a processing circuit includes, for example, an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each of the "~ units" may use a common processing circuit (the same processing circuit) or may use different processing circuits (separate processing circuits). Information input to and output from the dose map creation unit 50, the final positional deviation calculation unit 52, the writing positional deviation calculation unit 54, the correction amount calculation unit 56, the correction amount map creation unit 58, the shot data generation unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76, as well as information being calculated, are stored in the memory 112 each time.

[0028] The drawing operation of the drawing apparatus 100 is controlled by a drawing control unit 76. Moreover, the transfer process of the irradiation time data of each shot to the deflection control circuit 130 is controlled by a transfer processing unit 74.

[0029] Moreover, drawing data (chip data) is input from outside the drawing device 100 and stored in the storage device 140. The chip data defines information on a plurality of graphic patterns that constitute the chip pattern. Specifically, for example, a coordinate string of each vertex coordinate is defined for each graphic pattern. In addition, it is also preferable that a graphic code or the like is defined. Alternatively, the graphic code, coordinates, and size may be defined.

[0030] 1 shows the configuration necessary for explaining the embodiment 1. The drawing device 100 may also include other configurations that are normally required.

[0031] FIG. 2 is a conceptual diagram showing the configuration of the shaping aperture array substrate in the first embodiment. In FIG. 2, holes (openings) 22 are formed in a matrix of p columns (y direction)×q columns (x direction) (p, q≧2) at a predetermined arrangement pitch in the shaping aperture array substrate 203. In the example of FIG. 2, for example, 512×512 columns of holes 22 are formed in the vertical and horizontal directions (x and y directions). The number of holes 22 is not limited to this. For example, 32×32 columns of holes 22 may be formed. Each hole 22 is formed in a rectangular shape with the same dimensions. Alternatively, it may be a circle with the same diameter. A part of the electron beam 200 passes through each of the multiple holes 22, thereby forming a multibeam 20. In other words, the shaping aperture array substrate 203 forms and emits the multibeam 20. The shaping aperture array substrate 203 is an example of an emission source of the multibeam 20.

[0032] FIG. 3 is a cross-sectional view showing the configuration of the blanking aperture array mechanism in the first embodiment. As shown in FIG. 3, the blanking aperture array mechanism 204 has a blanking aperture array substrate 31 using a semiconductor substrate made of silicon or the like arranged on a support substrate 33. In a membrane region 330 at the center of the blanking aperture array substrate 31, a passing hole 25 (opening) for passing each beam of the multi-beam 20 is opened at a position corresponding to each hole 22 of the shaping aperture array substrate 203 shown in FIG. 2. Then, a pair of a control electrode 24 and a counter electrode 26 (blanker: blanking deflector) is arranged at a position facing each other across the corresponding passing hole 25 among the plurality of passing holes 25. In addition, a control circuit 41 (logic circuit) that applies a deflection voltage to the control electrode 24 for each passing hole 25 is arranged inside the blanking aperture array substrate 31 near each passing hole 25. The counter electrode 26 for each beam is connected to ground.

[0033] An amplifier (one example of a switching circuit) (not shown) is disposed within the control circuit 41. As one example of the amplifier, a CMOS (Complementary MOS) inverter circuit serving as a switching circuit is disposed. Either an L (low) potential (e.g., ground potential) lower than the threshold voltage or an H (high) potential (e.g., 1.5 V) equal to or higher than the threshold voltage is applied as a control signal to the input (IN) of the CMOS inverter circuit. In the first embodiment, when an L potential is applied to the input (IN) of the CMOS inverter circuit, the output (OUT) of the CMOS inverter circuit applied to the control circuit 41 becomes a positive potential (Vdd), and the corresponding beam is deflected by an electric field due to a potential difference with the ground potential of the counter electrode 26, and the beam is controlled to be turned OFF by being shielded by the limiting aperture substrate 206. On the other hand, when an H potential is applied to the input (IN) of the CMOS inverter circuit (active state), the output (OUT) of the CMOS inverter circuit becomes ground potential, and since there is no potential difference with the ground potential of the opposing electrode 26 and the corresponding beam is not deflected, the beam is controlled to be turned ON by passing through the limiting aperture substrate 206. Blanking control is performed by such deflection.

[0034] Next, a specific example of the operation of the drawing mechanism 150 will be described. An electron beam 200 emitted from an electron gun 201 (emission source) illuminates the entire shaping aperture array substrate 203 almost perpendicularly by an illumination lens 202. A plurality of rectangular holes 22 (openings) are formed in the shaping aperture array substrate 203, and the electron beam 200 illuminates an area including all of the plurality of holes 22. Each part of the electron beam 200 irradiated to the position of the plurality of holes 22 passes through each of the plurality of holes 22 of the shaping aperture array substrate 203, thereby forming a multi-beam (a plurality of electron beams) 20 having, for example, a rectangular shape. The multi-beam 20 passes through the corresponding blankers of a blanking aperture array mechanism 204. The blankers perform blanking control on the beams passing through them individually so that the beams are in an ON state for a set drawing time (irradiation time).

[0035] The multi-beam 20 that has passed through the blanking aperture array mechanism 204 is reduced by the reduction lens 205 and advances toward the central hole formed in the limiting aperture substrate 206. Here, the electron beams deflected by the blanker of the blanking aperture array mechanism 204 are displaced from the central hole of the limiting aperture substrate 206 and are blocked by the limiting aperture substrate 206. On the other hand, the electron beams that have not been deflected by the blanker of the blanking aperture array mechanism 204 pass through the central hole of the limiting aperture substrate 206 as shown in FIG. 1. In this way, the limiting aperture substrate 206 blocks each beam that has been deflected by the blanker of the blanking aperture array mechanism 204 to be in a beam OFF state. Then, each beam for one shot is formed by the beams that have passed through the limiting aperture substrate 206 and that have been formed from when the beam is turned ON until the beam is turned OFF. The multi-beams 20 that have passed through the limiting aperture substrate 206 are focused by the objective lens 207 to become a pattern image with a desired reduction ratio, and the entire multi-beams 20 that have passed through the limiting aperture substrate 206 are deflected in the same direction by the deflectors 208 and 209, and each beam is irradiated onto its respective irradiation position on the sample 101. Also, for example, when the XY stage 105 is moving continuously, the deflector 208 performs tracking control so that the irradiation position of the beam follows the movement of the XY stage 105. The multi-beams 20 irradiated at one time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the multiple holes 22 in the shaping aperture array substrate 203 by the desired reduction ratio described above.

[0036] Here, by using an LTEM substrate as the sample to be written, thermal expansion caused by irradiation with a single or multiple electron beams hardly occurs. Therefore, the problem of misalignment of the writing position caused by thermal expansion has been greatly improved to a negligible level. However, it has been found that the accumulation of the dose caused by multiple electron beam irradiations causes an irreversible shrinkage phenomenon in the glass substrate that serves as the sample 101.

[0037] FIG. 4 is a diagram showing an example of an evaluation substrate in the first embodiment. An LTEM substrate is used as the evaluation substrate. Specifically, a mask blank is used in which, for example, a chromium (Cr) film is formed on an LTEM substrate and a resist film is formed on the Cr film. FIG. 4 shows an example of a pattern after three drawing processes. Each drawing process is performed in the y direction from the lower side to the upper side of the evaluation substrate. In the first drawing process (1S), multiple cross patterns are drawn in a lattice pattern on the entire evaluation substrate. In the second drawing process (2S), L-shaped patterns are drawn in the vicinity of each cross pattern, for example, in the upper right and lower left, and a rectangular pattern with different pattern density in the lower and upper halves of the evaluation substrate is drawn as the background of the multiple cross patterns. For example, the background of the lower half drawn in the first half is set to a pattern density of, for example, 3%. The background of the upper half drawn in the second half is set to a pattern density of, for example, 75%. In the third drawing process (3S), L-shaped patterns are drawn in the vicinity of each cross pattern, for example, in the upper left and lower right. After each drawing process, the position of each drawn pattern is measured. The position of the pattern is measured by a position measuring device (not shown).

[0038] 5 is a diagram showing an example of the relationship between the amount of misalignment of an evaluation substrate in the first embodiment and an example of deformation of the substrate. FIG. 5 shows an example of a graph of the amount of misalignment Δx in the x direction in a state (2S-1S) obtained by subtracting the position of each pattern after drawing process 1S from the position of each pattern after drawing process 2S. As shown in the graph (2S-1S), it can be seen that the amount of misalignment Δx is small when the background pattern density is 3%, whereas the amount of misalignment Δx increases as the area subjected to drawing process increases when the background pattern density is 75%. This shows that deformation due to shrinkage of the glass substrate increases depending on the amount of irradiation. FIG. 5 shows an example of a graph of the positional deviation Δx in the x direction and an example of a graph of the positional deviation Δy in the y direction in the state (3S-1S) where the position of each pattern after the writing process 1S is subtracted from the position of each pattern after the writing process 3S. As shown in the graph of (3S-1S), the positional deviation Δx at 2S continues to remain after 3S. It can also be seen that the lower half of the substrate is also deformed in response to the contraction of the upper half of the substrate, and at the stage of 3S, a shift occurs in the substrate position and the positional deviation Δx becomes large. It can also be seen that the positional deviation ΔY in the y direction also gradually increases in the upper half of the substrate. This is due to the fact that the upper half of the substrate is irradiated with a relatively large amount of beam, causing a large deformation due to contraction in the upper half. As shown in this figure, 2S causes large shrinkage and deformation in the upper half of the substrate.

[0039] FIG. 6 is a diagram showing an example of a state when the evaluation substrate is irradiated with a beam in the first embodiment. In FIG. FIG. 7 is a diagram showing an example of a stress state caused by beam irradiation on an evaluation substrate in the first embodiment. In FIG. As described above, a mask blank in which, for example, a chromium (Cr) film 13 is formed on an LTEM substrate 12 and a resist film 16 is formed on the Cr film 13 is used as the evaluation substrate in FIG. 6. When an electron beam is irradiated to such an evaluation substrate, the electron beam reaches the LTEM substrate 12 and penetrates about several tens of μm from the surface of the LTEM substrate 12. This causes irreversible local contraction at the irradiated position of the LTEM substrate 12. By irradiating the beam at multiple points, tensile stress is generated near the substrate surface due to each local contraction in the entire beam-irradiated region. This causes irreversible deformation due to the contraction phenomenon near the surface of the LTEM substrate 12. Note that, since the deformation at a depth of, for example, 20 μm is small in volume compared to the thickness dimension (for example, 6.35 mm) of the LTEM substrate 12, the nature of the thermal deformation in the entire substrate does not change. Therefore, reversible deformation caused by thermal expansion can be ignored.

[0040] FIG. 8 is a diagram showing an example of a state of misalignment on the substrate surface in Comparative Example 1 of the first embodiment. In FIG. FIG. 9 is a diagram showing an example of deformation of a substrate surface in Comparative Example 1 of the first embodiment. 8 and 9 respectively show a state before the start of the drawing process, a state when drawing at a desired position, and a state after the drawing process is completed. In FIG. 8, the designed beam irradiation position is indicated by vector A. As the writing process proceeds on the target LTEM substrate, at the time when the position of vector A is written, the position of vector A before the writing process starts has physically moved to the position of vector B due to deformation caused by the contraction of the substrate as shown in FIG. 9. Then, as the writing process proceeds further, after the writing process on the entire substrate is completed, the position of vector A before the writing process starts has physically moved to the position of vector C due to further deformation as shown in FIG. 9. Therefore, if the position of vector A before the writing process starts is written as it is, after the writing process on the entire substrate is completed, the written beam irradiation position will be shifted to a position (vector A+(vector C-vector B)) that is moved by the vector indicated by (vector C-vector B) from the position of vector A before the writing process starts. Therefore, in the first embodiment, even if such irreversible deformation occurs on the substrate, the irradiation position during writing (pattern formation position) is corrected so that the beam irradiation position after the writing process is completed will be the position of vector A before the writing process starts.

[0041] FIG. 10 is a diagram showing an example of a state of positional deviation of the substrate surface in the first embodiment. An example of deformation of the substrate surface in the first embodiment is the same as that in FIG. 9. In FIG. 10, the designed beam irradiation position is indicated by vector A. As the writing process proceeds with respect to the target LTEM substrate, at the time when the position of vector A is written, the position of vector A before the writing process starts has physically moved to the position of vector B due to deformation caused by the contraction of the substrate as shown in FIG. 9. Then, as the writing process proceeds further, after the writing process of the entire substrate is completed, the position of vector A before the writing process starts has physically moved to the position of vector C due to further deformation as shown in FIG. 9. Therefore, during writing, a position (vector A+(vector B-vector C)) corrected by the vector indicated by (vector B-vector C) from the position of vector A before the process starts is written as the beam irradiation position (or pattern formation position). As a result, after the drawing process for the entire substrate is completed, the drawn beam irradiation position (or pattern formation position) can be located at the position of vector A, which is a position moved from the position (vector A + (vector B - vector C)) by the vector indicated by (vector C - vector B).

[0042] Fig. 11 is a flow chart showing an example of main steps of the writing method in the first embodiment. Fig. 11 shows a flow chart showing a case where writing processing is performed in a real-time mode in which a calculation process for correcting a beam irradiation position (or a pattern formation position) of a next region is performed while writing operation is being performed. In Fig. 11, the writing method in the first embodiment performs a series of steps including a dose map creation step (S102), a final positional deviation amount (vector C) calculation step (S104), a writing schedule creation step (S106), a writing positional deviation amount (vector B) calculation step (S108), a correction amount calculation step (S110), a writing step (S170), and a determination step (S172).

[0043] Fig. 12 is a flow chart showing another example of the main steps of the writing method in the first embodiment. Fig. 12 shows a flow chart showing a case where writing processing is performed in a pre-processing mode in which a calculation process for correcting the beam irradiation positions (or pattern formation positions) of all regions is performed as a pre-processing, and then writing operation is started. In Fig. 12, the writing method in the first embodiment performs a series of steps including a dose map creation step (S102), a final positional deviation amount (vector C) calculation step (S104), a writing schedule creation step (S106), a writing positional deviation amount (vector B) calculation step (S108), a correction amount calculation step (S110), a determination step (S112), a correction amount map creation step (S114), and a writing step (S170).

[0044] The writing process is performed for each stripe region (described later) obtained by dividing the writing region of the sample 101 in the y direction, for example. In the real-time mode, the writing operation for the k-th stripe region and the correction calculation process for the k+m-th stripe region are performed simultaneously. In the pre-processing mode, the writing operation is started after the correction calculation processes for all stripe regions are completed.

[0045] In the dose map creation step (S102), the dose map creation unit 50 creates a dose map in which a dose amount is defined for each pixel, which will be described later. Specifically, the operation is as follows. The dose map creation unit 50 first virtually divides a drawing region (e.g., a stripe region) into a plurality of proximity mesh regions (mesh regions for calculating proximity effect correction) in a mesh shape of a predetermined size. The size of the proximity mesh region is preferably set to about 1 / 10 of the range of influence of the proximity effect, for example, about 1 μm. The dose map creation unit 50 reads out drawing data from the storage device 140, and calculates, for each proximity mesh region, a pattern area density ρ″ of a pattern arranged in the proximity mesh region.

[0046] Next, the dose map creation unit 50 calculates a proximity effect correction irradiation coefficient Dp(x) for correcting the proximity effect for each proximity mesh region. The unknown proximity effect correction irradiation coefficient Dp(x) can be defined by a threshold model for proximity effect correction similar to the conventional method, using a backscattering coefficient η, a dose threshold Dth of a threshold model, a pattern area density ρ″, and a distribution function g(x).

[0047] Next, the dose map creation unit 50 calculates the incident dose D(x) (dose) for each pixel to irradiate the pixel. The incident dose D(x) may be calculated as, for example, a value obtained by multiplying the reference dose Dbase by the proximity effect correction irradiation coefficient Dp and the pattern area density ρ'. The reference dose Dbase may be defined as, for example, Dth / (1 / 2+η). In this way, the incident dose D(x) for each pixel, in which the proximity effect is corrected based on the layout of a plurality of figure patterns defined in the drawing data, can be obtained. Alternatively, the dose map creation unit 50 calculates an irradiation coefficient for irradiating the pixel for each pixel. The irradiation coefficient d(x) may be calculated as, for example, a value obtained by multiplying the proximity effect correction irradiation coefficient Dp by the pattern area density ρ'. In other words, it may be calculated as a modulation rate of the reference dose Dbase. This makes it possible to obtain the dose (irradiation coefficient) d(x) as a relative value normalized with the reference dose Dbase as 1, rather than the absolute value of the dose.

[0048] Next, the dose map creation unit 50 creates a dose map with the dose of each pixel as an element. In other words, each pixel (position) (x, y) is defined in association with the dose D (or d) of that pixel. The created dose map is stored in the storage device 142. The dose map creation unit 50 creates a dose map for the entire drawing in which drawing processing is performed according to the drawing data (chip data).

[0049] In the final positional deviation amount (vector C) calculation step (S104), the final positional deviation amount calculation unit 52 calculates a final positional deviation amount (first positional deviation amount) of a pattern from a designed position caused by irreversible deformation of the sample 101 after completion of writing processing when a pattern is written by irradiating the sample 101 with an electron beam, the sample 101 being irreversibly deformed depending on the distribution of the dose of the electron beam. In other words, the final positional deviation amount calculation unit 52 calculates a final positional deviation amount (first positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position caused by irreversible deformation of the sample 101 after completion of writing when a pattern is written using an electron beam on the sample 101 being irreversibly deformed by irradiation with the electron beam. Specifically, the final positional deviation amount calculation unit 52 calculates a positional deviation amount (vector C) of each position after completion of writing processing on the sample 101.

[0050] The range of influence of the global misalignment amount is in the range of several hundreds of μm to several mm. Therefore, the range of influence of the global misalignment amount is larger than the beam array size (x direction and y direction) of the multi-beam 20, for example, several tens of μm. Therefore, the final misalignment amount calculation unit 52 first virtually divides the area of ​​the sample 101 surface into a plurality of global mesh areas 11 in a mesh shape with a predetermined size, as shown in FIG. 15. It is preferable to set the size of the global mesh area 11 to about 1 / 10 of the range of influence of the global misalignment amount, that is, several tens of μm to several hundreds of μm. For example, when the beam array size is about 80 μm, it is preferable to set it to about half of that, about 40 μm. However, it is not limited to the case where it is smaller than the beam array size. It may be a size equal to or larger than the beam array size.

[0051] Then, the final positional deviation calculation unit 52 calculates a vector C at a representative point (e.g., a central position) in each global mesh region 11 (position). Each vector C is calculated as a final positional deviation (dxfinal-i, dyfinal-i), where i indicates the index of each global mesh region 11. The final positional deviation of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the final positional deviation of the pattern formation position or beam irradiation position. The final positional deviation amount (dxfinal-i, dyfinal-i) of each global mesh region 11 depends on the dose (dosage coefficient) defined in the dose map, and can be calculated using, for example, the finite element method.

[0052] FIG. 13 is a diagram showing an example of the relationship between the reduction ratio and the dose of the substrate in the first embodiment. In FIG. 13, the vertical axis shows the reduction ratio, and the horizontal axis shows the dose. In the example of FIG. 13, dies a to d are drawn with variable pattern area density ρ and irradiation dose D. Then, the distortion (reduction ratio: ΔL / L) in each die is calculated, and the relationship between the distortion (reduction ratio) and ρD (total dose per unit area) is calculated. L indicates the size of the substrate, and ΔL indicates the amount of positional deviation. As shown in the example of FIG. 13, it can be seen that the distortion (reduction ratio) increases in proportion to ρD. Therefore, the distortion (reduction ratio) can be obtained using the irradiation amount (irradiation coefficient) defined in the dose map.

[0053] Fig. 14 is a diagram showing an example of a model based on the finite element method in embodiment 1. In the example of Fig. 14, a 6-inch mask, which is an example of the sample 101, is divided into triangular pyramid elements. A triangular pyramid element has four vertices, each of which is related to a displacement vector u = (u x ,u y ,u z ) three-dimensional displacement information. In other words, one unit element has a total of 4 × 3 = 12 variables. In the relational equation ε = Bu between this displacement vector u (12 × 1) and the strain vector ε (6 × 1), the strain-displacement matrix M1 (6 × 12) of the unit element is expressed, for example, by the following equation (1).

[0054]

number

[0055] On the other hand, in the relational equation σ = Dε between the stress vector σ (6 × 1) and the strain vector ε (6 × 1), the material property matrix M2 (6 × 6) of the unit element is expressed as the following equation (2) using the Young's modulus E and Poisson's ratio ν of the quartz substrate.

[0056]

number

[0057] Here, the distortion e of the substrate surface caused by the charged particle beam irradiation dose Q (=ρD) is defined by the following equation (3) using coefficients c0 and c1.

[0058]

number

[0059] If we assume that the shear strain caused by charged particle beam irradiation is zero, the strain vector ε of the unit element can be defined by the following equation (4).

[0060]

number

[0061] The stiffness matrix per unit element is then written as follows:

[0062]

number

[0063] Here, t means the transposed matrix. The above equations are combined for all elements, and the displacement vectors U of all vertices, the global stiffness matrix K, and the equivalent nodal forces f are defined as the following equations (6-1), (6-2), and (6-3).

[0064]

number

[0065] As a result, it is expressed as the following equation (7).

[0066]

number

[0067] Finally, the total displacement vector U can be calculated using the following equation (8).

[0068]

number

[0069] To calculate the final positional deviation (dxfinal-i, dyfinal-i) for each position, first, the value of the element of the dose map created from the layout is substituted into Q in equation (3) to obtain the distortion e of each element and the distortion vector ε of equation (4). Then, f of equation (6-3) is obtained under the obtained distortion vector ε of each element, and equation (8) is solved to obtain the total displacement vector U including the displacement vector u of each element when all dose irradiation of drawing is completed. The displacement amount (u x ,u y ) can be obtained as the final positional deviation amount (dxfinal-i, dyfinal-i). The calculated final positional deviation amount for each position is stored in the storage device 142.

[0070] In the writing schedule creation step (S106), the writing control unit 76 creates a writing schedule that defines the shot order of each pixel defined in the dose map. This allows the position and dose of irradiation to be known for each shot up to the time when the shot is performed (writing time).

[0071] As a writing positional deviation amount (vector B) calculation step (S108), the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) from a design position of a pattern generated at the time of electron beam irradiation in the writing process due to irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before the irradiation time of the electron beam. In other words, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) of a pattern formation position or a beam irradiation position from a design position at the time of irradiation of a target electron beam caused by irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before the irradiation of the target electron beam. Specifically, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (vector B) of a representative position in each global mesh region 11. The vector B of each global mesh region 11 is calculated as a writing positional deviation amount (dxwrite-n, dywrite-n). n indicates an index of each global mesh region 11. The positional deviation amount at the time of writing of the global mesh region 11 including the pattern formation position or the beam irradiation position corresponds to the positional deviation amount at the time of writing of the pattern formation position or the beam irradiation position. The positional deviation amount at the time of writing (dxwrite-n, dywrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, by using the finite element method, as described above. Specifically, the dose of each element when irradiation up to n is completed among the doses defined in the dose map is substituted for Q in formula (3) to obtain the distortion e of each element and the distortion vector ε in formula (4). Then, f in formula (6-3) is obtained under the obtained distortion vector ε of each element, and formula (8) is solved to obtain the total displacement vector U including the displacement vector u of each element when irradiation up to n is completed, and the displacement amount (u x ,uy ) can be calculated as the amount of positional deviation during writing (dxwrite-n, dywrite-n).

[0072] In the above example, the amount of misregistration during drawing is calculated for each global mesh region 11, but the present invention is not limited to this. It is also preferable to calculate the amount of misregistration during drawing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0073] In the correction amount calculation step (S110), the correction amount calculation unit 56 calculates a correction amount (vector B-vector C) (first correction amount) for correcting the pattern position or the electron beam irradiation position when forming a pattern by irradiating the sample 101 with an electron beam based on the final positional deviation amount. In other words, the correction amount calculation unit 56 calculates a correction amount (vector B-vector C) (first correction amount) for correcting the pattern formation position or the beam irradiation position when irradiating the sample 101 with the multi-beam 20 (electron beam), based on the final positional deviation amount due to irreversible deformation of the sample 101 after writing is completed. The correction amount (vector B-vector C) (first correction amount) is calculated based on the difference between the writing positional deviation amount (vector B) and the final positional deviation amount (vector C). In other words, the correction amount (dxn, dyn) of each position in the global mesh area 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the writing positional deviation amount (dxwrite-n, dywrite-n) from the final positional deviation amount (dxfinal-n, dyfinal-n).

[0074] The correction amount map creating unit 58 creates a correction amount map in which the correction amount (dxn, dyn) for each global mesh region (xn, yn) is defined. The correction amount map is stored in the storage device 142.

[0075] When the process up to the calculation of the correction amount is completed for each stripe region, the process proceeds to the writing step (S170) in the real-time mode.

[0076] 15 is a conceptual diagram for explaining an example of the writing operation in the embodiment 1. As shown in FIG 15, the position of a writing region 30 (bold line) of the sample 101 is defined based on the position of an alignment mark 14. The writing area 30 (bold line) is virtually divided into a plurality of rectangular stripe areas 32 with a predetermined width in the y direction, for example. The example of FIG. 15 shows a case where the writing area 30 of the sample 101 is divided into a plurality of stripe areas 32 with a width size substantially the same as the size of the designed irradiation area 34 (beam array area) that can be irradiated by one irradiation of the multibeam 20, for example, in the y direction. The size in the x direction of the designed irradiation area 34 of the multibeam 20 can be defined by the number of beams in the x direction × the beam pitch in the x direction. The size in the y direction of the rectangular irradiation area 34 can be defined by the number of beams in the y direction × the beam pitch in the y direction.

[0077] First, the XY stage 105 is moved and adjusted so that the irradiation area 34 of the multi-beam 20 is positioned at the left end of the first stripe area 32 or at a position further to the left, and the first stripe area 32 is written. When writing the first stripe area 32, the XY stage 105 is moved, for example, in the -x direction, so that writing proceeds relatively in the x direction. The XY stage 105 is moved continuously, for example, at a constant speed. After writing the first stripe area 32 is completed, the stage position is moved in the -y direction by the size of the width of the stripe area 32.

[0078] Next, the irradiation area 34 of the multibeam 20 is adjusted to be located at the left end of the second stripe area 32 or at a position further to the left, and the XY stage 105 is moved, for example, in the -x direction, thereby relatively progressing the drawing in the x direction, thereby drawing the second stripe area 32. Thereafter, drawing is similarly performed in order from the lower stripe area 32 toward the upper side (y direction).

[0079] In the example of FIG. 15, the stripe regions 32 are drawn in the same direction, but the present invention is not limited to this. For example, the stripe region 32 to be drawn next to the stripe region 32 drawn in the x direction may be drawn in the -x direction by moving the XY stage 105 in the x direction, for example. By drawing while changing the direction alternately in this way, the stage movement time can be shortened, and thus the drawing time can be shortened. In one shot, a plurality of shot patterns, the same number as the number of holes 22 at most, are formed at once by the multi-beam 20 formed by passing through each hole 22 of the shaping aperture array substrate 203.

[0080] FIG. 16 is a diagram showing an example of a multibeam irradiation area and a pixel to be written in the first embodiment. In FIG. 16, the stripe area 32 is divided into a plurality of mesh areas in a mesh shape by the beam size of the multibeam 20, for example. Each mesh area is a pixel 36 to be written (unit irradiation area, irradiation position, or writing position). The size of the pixel 36 to be written is not limited to the beam size, and may be an arbitrary size regardless of the beam size. For example, the size may be 1 / n (n is an integer equal to or greater than 1) of the beam size. The example of FIG. 16 shows a case where the writing area of ​​the sample 101 is divided into a plurality of stripe areas 32 in the y direction, for example, with a width substantially equal to the size of the irradiation area 34 (writing field) that can be irradiated by one irradiation of the multibeam 20. The size of the rectangular irradiation area 34 in the x direction can be defined by the number of beams in the x direction x the beam pitch in the x direction. The size of the rectangular irradiation area 34 in the y direction can be defined by the number of beams in the y direction x the beam pitch in the y direction. In the example of FIG. 32, for example, a 512×512 array of multi-beams is shown in an abbreviated form to an 8×8 array of multi-beams. A plurality of pixels 28 (beam drawing positions) that can be irradiated with one shot of the multi-beam 20 are shown in the irradiation area 34. The pitch between adjacent pixels 28 is the pitch between each beam of the multi-beam. A rectangular area surrounded by the size of the beam pitch in the x and y directions constitutes one sub-irradiation area 29 (pitch cell). In the example of FIG. 32, a case is shown in which each sub-irradiation area 29 is constituted by, for example, 4×4 pixels.

[0081] In the writing process (S170), first, the shot data generating unit 70 calculates the incident irradiation amount D(x) (dose amount) for each pixel 36 to be irradiated to the pixel 36. The incident irradiation amount D(x) may be calculated, for example, as a value obtained by multiplying the reference irradiation amount Dbase by the proximity effect correction irradiation coefficient Dp and the pattern area density ρ'. The reference irradiation amount Dbase may be defined, for example, as Dth / (1 / 2+η). In this way, the incident irradiation amount D(x) for each pixel 36, in which the proximity effect is corrected based on the layout of the multiple figure patterns defined in the writing data, can be obtained. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. If the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as it is.

[0082] Next, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0083] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0084] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount. In other words, the drawing mechanism 150 corrects the pattern position or the electron beam irradiation position when the sample 101 is irradiated with the electron beam to form a pattern based on the final positional deviation amount, and performs drawing processing to draw a pattern on the sample 101. The drawing mechanism 150 performs such correction based on the difference between the positional deviation amount at the time of drawing and the final positional deviation amount. The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dxn, dyn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the center beam) for each tracking cycle of the multi-beam 20 described later. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the central position or the position of the central beam).

[0085] Fig. 17 is a diagram for explaining an example of a multi-beam writing operation in the first embodiment. The example of Fig. 17 shows a case where writing is performed with four different beams in each sub-irradiation area 29 that includes one beam irradiation position of each of the multi-beams 20 and is surrounded by the inter-beam pitch. Also, the example of Fig. 17 shows a writing operation in which the XY stage 105 moves continuously at a speed of moving by a distance of, for example, two beam pitches while writing an area of ​​1 / 4 (one of the number of beams used for irradiation) in each sub-irradiation area 29. The example of Fig. 17 shows a case where each sub-irradiation area 29 is composed of, for example, 4 x 4 pixels.

[0086] In the drawing operation shown in the example of FIG. 17, for example, while the XY stage 105 moves a distance of two beam pitches in the x direction, the deflector 209 shifts the irradiation position (pixel 36) in sequence, and four shots of the multibeam 20 are fired in a shot cycle T to draw (expose) four different pixels 36 in the same sub-irradiation region 29. While drawing (exposing) the four pixels 36, the deflector 208 deflects the entire multibeam 20 collectively so that the relative position of the irradiation region 34 to the sample 101 does not shift due to the movement of the XY stage 105, thereby making the irradiation region 34 follow the movement of the XY stage 105. In other words, tracking control is performed. In the example of FIG. 17, the tracking cycle is given as an example of the time for the XY stage 105 to move a distance of two beam pitches in the x direction, but is not limited thereto. It may be the time for moving a distance greater than the distance of two beam pitches, for example, a distance of 8 beam pitches or a distance of 16 beam pitches.

[0087] When one tracking cycle is completed, tracking is reset and the system returns to the previous tracking start position. Since the drawing of the first pixel row from the left of each sub-irradiation region 29 is completed, the deflector 209 first deflects (shifts) the drawing position of the beam different from the first pixel row so as to draw an undrawn pixel row, for example, the second pixel row from the left, of each sub-irradiation region 29 in the next tracking cycle after tracking reset. By repeating this operation during drawing of the stripe region 32, the position of the irradiation region 34 (34a to 34o) of the multi-beam 20 moves sequentially as shown in the lower diagram of FIG. 15, and drawing is performed.

[0088] Therefore, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a position corrected by the correction amount (dxn, dyn) of the global mesh region 11 including the representative position of the beam array (e.g., the central position, or the position of the central beam) for each tracking cycle, and during the tracking cycle, while each beam draws (exposes), for example, four pixels 36 at that position, the deflector 208 deflects the entire multi-beam 20 collectively so that the beam array (irradiation region 34) does not shift in relative position to the sample 101 due to the movement of the XY stage 105, thereby causing the beam array (irradiation region 34) to follow the movement of the XY stage 105.

[0089] As shown in the lower diagram of FIG. 15, the position of the irradiation area 34 (34a to 34o) of the multi-beam 20 gradually moves. Therefore, there are cases where the multi-beam 20 is shot in a state where the irradiation area 34 (beam array) straddles adjacent global mesh areas 11. Including such cases, it is sufficient to use the correction amount (dxn, dyn) of the global mesh area 11 that includes the representative position (for example, the center position or the position of the central beam) of the irradiation area 34 (beam array).

[0090] 11, while the drawing process is being performed, shot data for the stripe region 32 to be subjected to the drawing process later is generated in parallel. For example, while drawing is being performed on the k-th stripe region 32, shot data for the k+2-th stripe region 32 is generated in parallel.

[0091] In the determination step (S172), the writing control unit 76 determines whether writing has been completed for all the stripe regions 32. If writing has not been completed yet, the process returns to the writing misalignment amount calculation step (S108), and the steps from the writing misalignment amount calculation step (S108) to the determination step (S172) are repeated for the next stripe region 32. In this manner, the steps from the writing misalignment amount calculation step (S108) to the determination step (S172) are repeated until writing has been completed for all the stripe regions 32.

[0092] 12, after performing the correction amount calculation step (S110) for each stripe region 32, the writing control unit 76 determines whether or not calculation of the correction amount has been completed for all stripe regions 32 as a determination step (S112). If not yet completed, the process returns to the writing misalignment amount calculation step (S108), and the writing misalignment amount calculation step (S108) to the determination step (S112) are repeated for the next stripe region 32. In this manner, the writing misalignment amount calculation step (S108) to the determination step (S112) are repeated until writing of all stripe regions 32 is completed.

[0093] In the correction amount map creating step (S114), the correction amount map creating unit 58 creates a correction amount map for the entire surface of the sample 101, in which the correction amount for each global mesh region 11 is an element value.

[0094] In the writing step (S170), the writing mechanism 150 writes a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount. The contents of the writing step (S170) are the same as those in the real-time mode. However, since a correction amount map for the entire area of ​​the sample 101 has already been created, it is not necessary to calculate the correction amount while writing. It is sufficient to write each stripe region 20 in sequence.

[0095] In the above example, the deflection position (beam irradiation position) of the beam array is corrected by the correction amount, but the method of correction is not limited to this. A modification of the first embodiment will be described below.

[0096] In a modification of the first embodiment, the shot data generation unit 70 first corrects the formation position of the pattern on the drawing data based on the correction amount map. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in that global mesh region 11 by the correction amount defined for that global mesh region 11.

[0097] Then, the shot data generating unit 70 creates a new dose map using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0098] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0099] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount. In the modification of the first embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dxn, dyn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, a center position or a position of a center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) for example, four pixels 36 at that position, the deflector 208 deflects the entire multi-beam 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0100] In the above-mentioned first embodiment, a case where one writing process is performed on the sample 101 has been described. Note that this one writing process refers to a process from the start of writing to the completion of writing of the entire writing region (chip region) of the sample 101. Therefore, this process may include, for example, multiple writing in which writing processes are repeated so that overlapping parts are written in multiple while shifting positions in stripe units in the y direction so that the overlapping parts are written in multiple, or multiple writing in which, for example, during one stripe writing of each stripe region 20, the same region written with a beam arranged on the front side of the writing direction of the multibeams 20 is repeatedly written with a beam arranged on the rear side of the writing direction of the multibeams 20.

[0101] As described above, according to the first embodiment, it is possible to correct positional deviations of the beam irradiation position and the pattern formation position caused by irreversible deformation of the sample 101 due to irradiation with the multi-beams 20 (electron beams).

[0102] Embodiment 2 In the second embodiment, a case will be described in which, after the drawing process for the entire drawing area (chip area) of the sample 101 has been completed, two-stroke drawing is performed again to draw the entire drawing area (chip area) of the sample 101 using the same layout pattern.

[0103] FIG. 18 is a conceptual diagram showing the configuration of the writing apparatus in the second embodiment. In FIG. 18, the writing position deviation amount calculation unit 62, the correction amount calculation unit 64, and the correction amount map creation unit 66 are further arranged in the control computer 110, and the configuration is the same as FIG. 1. Each of the "~ units" such as the dose map creation unit 50, the final position deviation amount calculation unit 52, the writing position deviation amount calculation unit 54, the correction amount calculation unit 56, the correction amount map creation unit 58, the writing position deviation amount calculation unit 62, the correction amount calculation unit 64, the correction amount map creation unit 66, the shot data generation unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76 has a processing circuit. Such a processing circuit includes, for example, an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each of the "~ units" may use a common processing circuit (the same processing circuit) or may use different processing circuits (separate processing circuits). Information input to and output from the dose map creation unit 50, the final positional deviation amount calculation unit 52, the writing positional deviation amount calculation unit 54, the correction amount calculation unit 56, the correction amount map creation unit 58, the writing positional deviation amount calculation unit 62, the correction amount calculation unit 64, the correction amount map creation unit 66, the shot data generation unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76, as well as information being calculated, are stored in the memory 112 each time. Either the writing positional deviation amount calculation unit 54 or the writing positional deviation amount calculation unit 62 may be configured to have the functions of both. In that case, the other can be omitted.

[0104] FIG. 19 is a diagram for explaining a method of two-stroke writing in the second embodiment. In FIG. 19, in the first writing process (first stroke), writing is performed in sequence from the lower stripe region 32 of the sample 101 toward the upper side (y direction). The diagram on the left side of FIG. 19 shows a state in which writing is performed at a certain position (indicated by x) during the first writing process. Then, after the first writing process of the entire writing region (chip region) of the sample 101 is completed, a second writing process (second stroke) is performed in which writing is repeatedly performed using writing data of the same pattern layout while the sample 101 is still placed on the stage 105. The diagram on the right side of FIG. 19 shows a state in which writing is performed at a certain position (indicated by x: the same position as in the diagram on the left side) during the second writing process.

[0105] FIG. 20 is a diagram showing an example of a state of misalignment on the substrate surface in a comparative example of the second embodiment. Figure 20 shows the state before the start of the first drawing process, the state when drawing at the desired position in the first drawing process, the state after the first drawing process is completed, the state when drawing at the desired position in the second drawing process, and the state after the second drawing process is completed.

[0106] In FIG. 20, the designed beam irradiation position is indicated by vector A. As the first drawing process proceeds on the target LTEM substrate, at the time when the position of vector A is drawn in the first drawing process, the position of vector A before the start of drawing process has physically moved to the position of vector B1 due to deformation caused by contraction of the substrate as shown in FIG. 20. Then, the drawing process proceeds further, and after the first drawing process is completed, the position of vector A before the start of drawing process has physically moved to the position of vector C1 due to further deformation as shown in FIG. 20. Then, the second drawing process is started, the drawing process proceeds, and at the time when the position of vector A is drawn in the second drawing process, the position of vector A before the start of drawing process has physically moved to the position of vector B2 due to deformation caused by contraction of the substrate as shown in FIG. Then, the drawing process proceeds further, and after the second drawing process is completed (after the drawing process of the entire substrate is completed), the position of vector A before the start of drawing process has physically moved to the position of vector C2 due to further deformation as shown in FIG. 20.

[0107] Therefore, if the position of vector A before the start of drawing processing is drawn as it is in the first drawing process, after the drawing processing of the entire substrate is completed, the drawn beam irradiation position will be shifted to a position (vector A+(vector C2-vector B1)) moved by the vector indicated by (vector C2-vector B1) from the position of vector A before the start of drawing processing. Similarly, if the position of vector A before the start of drawing processing is drawn as it is in the second drawing process, after the drawing processing of the entire substrate is completed, the drawn beam irradiation position will be shifted to a position (vector A+(vector C2-vector B2)) moved by the vector indicated by (vector C2-vector B2) from the position of vector A before the start of drawing processing. Therefore, in embodiment 2, even if such irreversible deformation occurs in the substrate, the irradiation position during drawing (pattern formation position) is corrected so that after the drawing process is completed, the beam irradiation position becomes the position of vector A before the drawing process started.

[0108] FIG. 21 is a diagram showing an example of a state of positional deviation of the substrate surface in the second embodiment. The state of deformation of the substrate surface in the second embodiment is not shown. In FIG. 21, the designed beam irradiation position is indicated by vector A. As the first drawing process proceeds with respect to the target LTEM substrate, at the time when the position of vector A is drawn in the first drawing process, the position of vector A before the start of the drawing process has physically moved to the position of vector B1 due to deformation caused by contraction of the substrate as shown in FIG. 21. Then, after the first drawing process is completed and the second drawing process is completed, the position of vector A before the start of the drawing process has physically moved to the position of vector C2 due to further deformation as shown in FIG. 21.

[0109] Therefore, when drawing in the first drawing process, it is sufficient to correct only the positional deviation amount (vector C2-vector B1) from the position at that time (vector B1) to the position after the drawing process of the entire substrate is completed (vector C2). Therefore, when drawing in the first drawing process, a position (vector A+(vector B1-vector C2)) corrected by the vector indicated by (vector B1-vector C2) from the position of vector A before the process starts is drawn as the beam irradiation position (or pattern formation position). As a result, after the drawing process of the entire substrate is completed after the second drawing process, the beam irradiation position (or pattern formation position) drawn in the first drawing process can be the position of vector A, which is the position moved by the vector indicated by (vector C2-vector B1) from the position (vector A+(vector B1-vector C2)).

[0110] Then, when the position of vector A is drawn in the second drawing process, the position of vector A before the drawing process starts has physically moved to the position of vector B2 due to deformation caused by shrinkage of the board, as shown in Figure 21. After the second drawing process ends and drawing processing of the entire board is completed, the position of vector A before the drawing process starts has physically moved to the position of vector C2, as described above.

[0111] Therefore, when drawing in the second drawing process, it is sufficient to correct only the positional deviation amount (vector C2-vector B2) from the position at that time (vector B2) to the position after the drawing process of the entire substrate is completed (vector C2). Therefore, when drawing in the second drawing process, a position (vector A+(vector B2-vector C2)) corrected by the vector indicated by (vector B2-vector C2) from the position of vector A before the process starts is drawn as the beam irradiation position (or pattern formation position). As a result, after the drawing process of the entire substrate is completed after the second drawing process, the beam irradiation position (or pattern formation position) drawn in the second drawing process can be the position of vector A, which is the position moved by the vector indicated by (vector C2-vector B2) from the position (vector A+(vector B2-vector C2)).

[0112] As a result of the above, the beam irradiation position drawn in the first drawing process and the beam irradiation position drawn in the second drawing process can both be made to be at the position of vector A before the drawing process started after the drawing process for the entire substrate is completed.

[0113] Fig. 22 is a flow chart showing an example of main steps of the writing method in the embodiment 2. In Fig. 22, the writing method in the embodiment 2 performs a series of steps including a dose map creating step (S101), a final positional deviation amount (vector C2) calculating step (S105), a writing schedule creating step (S107), a writing positional deviation amount (vector B1) calculating step (S120), a correction amount calculating step (S122), a determination step (S124), a first correction amount map creating step (S126), a writing positional deviation amount (vector B2) calculating step (S130), a correction amount calculating step (S132), a determination step (S134), a second correction amount map creating step (S136), a first writing step (S174), and a second writing step (S176). The writing process in the second embodiment includes a first writing process for writing a first chip pattern, and a second writing process that is performed after the first writing process and writes a second chip pattern so as to overlap the first chip pattern. In the second embodiment, the second chip pattern is the same chip pattern as the first chip pattern.

[0114] 22 shows a flowchart for performing drawing processing in a preprocessing mode in which a drawing operation is started after a calculation process for correcting the beam irradiation position (or the pattern formation position) of all regions is performed as a preprocessing. A flowchart for performing drawing processing in a real-time mode in which a calculation process for correcting the beam irradiation position (or the pattern formation position) of the next region is performed while a drawing operation is being performed is omitted.

[0115] In the real-time mode, the drawing operation of the kth stripe region in the first drawing process and the correction calculation process (drawing position deviation amount (vector B1) calculation process (S120), correction amount calculation process (S122), judgment process (S124), and first correction amount map creation process (S126)) of the k+mth stripe region are performed simultaneously. Then, the first drawing process (S174) is performed sequentially for the stripe regions 32 for which the correction calculation process has been completed. Similarly, the writing operation of the kth stripe region in the second writing process and the correction calculation process (writing position deviation amount (vector B2) calculation process (S130), correction amount calculation process (S132), judgment process (S134), and second correction amount map creation process (S136)) of the k+mth stripe region are performed simultaneously. Then, the second writing process (S176) is sequentially performed for the stripe regions 32 for which the correction calculation process has been completed.

[0116] In the dose map creating step (S101), the dose map creating unit 50 creates a dose map in which the dose amount is defined for each pixel. Here, a dose map for the first drawing process (first dose map) and a dose map for the second drawing process (second dose map) are created. Since the drawing process of the same layout pattern is performed in two strokes, for example, the dose amount incident on each pixel is divided in half. In such a case, the first dose map and the second dose map are generally the same dose map. The method of creating the dose map may be the same as the contents of the dose map creating step (S102) described above.

[0117] In the final positional deviation amount (vector C2) calculation step (S105), the final positional deviation amount calculation unit 52 calculates a final positional deviation amount (first positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position due to irreversible deformation of the sample 101 after writing is completed when a pattern is written using an electron beam on the sample 101 that is irreversibly deformed by irradiation with the electron beam. Specifically, the final positional deviation amount calculation unit 52 calculates a positional deviation amount (vector C2) of each position after the first writing process and the second writing process are completed and the writing process on the sample 101 is completed. In other words, the final positional deviation amount is a positional deviation amount from a designed position of a pattern due to irreversible deformation of the sample 101 after the second writing process is completed.

[0118] Then, the final positional deviation calculation unit 52 calculates a vector C2 at a representative point (e.g., a central position) in each global mesh region 11 (position). Each vector C2 is calculated as a final positional deviation (dxfinal-i, dyfinal-i), where i indicates the index of each global mesh region 11. The final positional deviation of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the final positional deviation of the pattern formation position or beam irradiation position. The final positional deviation amount (dxfinal-i, dyfinal-i) of each global mesh region 11 depends on the irradiation dose (irradiation coefficient) defined in the dose map, and can be calculated, for example, using the finite element method, as described above.

[0119] In the writing schedule creation step (S107), the writing control unit 76 creates a writing schedule that defines the shot order of each pixel defined in the dose map. Here, a writing schedule is created for each of the first writing process and the second writing process. This makes it possible to know the irradiated position and the irradiation amount for each shot up to the time when the shot is performed (at the time of writing).

[0120] As a writing positional deviation amount (vector B1) calculation step (S120), the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) from a designed position caused by irreversible deformation of the sample 101 caused by the electron beam irradiated to the sample 101 before the irradiation time of the electron beam in the first writing process at the time of irradiation of the electron beam. In other words, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position at the time of irradiation of the target electron beam in the first writing process caused by irreversible deformation of the sample 101 caused by the electron beam irradiated to the sample 101 before the irradiation of the target electron beam in the first writing process. Specifically, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (vector B1) of a representative position in each global mesh region 11. The vector B1 of each global mesh region 11 is calculated as the amount of misalignment at the time of writing (dx1stwrite-n, dy1stwrite-n), where n indicates the index of each global mesh region 11. The amount of misalignment at the time of writing of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the amount of misalignment at the pattern formation position or beam irradiation position at the time of writing. The amount of misalignment at the time of writing (dx1stwrite-n, dy1stwrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, using the finite element method, as described above.

[0121] In the above example, the amount of misregistration during drawing is calculated for each global mesh region 11, but the present invention is not limited to this. It is also preferable to calculate the amount of misregistration during drawing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0122] In the correction amount calculation step (S122), the correction amount calculation unit 56 calculates a correction amount (vector B1-vector C2) (first correction amount) for correcting a pattern formation position or a beam irradiation position when the sample 101 is irradiated with a target electron beam (multibeam 20) in the first writing process, based on a final positional deviation amount due to irreversible deformation of the sample 101 after writing is completed. The correction amount (vector B1-vector C2) (first correction amount) is calculated based on a difference between the writing positional deviation amount (vector B1) and the final positional deviation amount (vector C2) of the first writing process. In other words, the correction amount calculation unit 56 calculates the first correction amount in the first writing process based on a difference between the writing positional deviation amount and the final positional deviation amount of the first writing process. In other words, the correction amount (dx1stn, dy1stn) of each position within the global mesh region 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the positional deviation amount at the time of drawing (dx1stwrite-n, dy1stwrite-n) from the final positional deviation amount (dxfinal-n, dyfinal-n).

[0123] In the determination step (S124), the writing control unit 76 determines whether calculation of the correction amount for the first writing process has been completed for all stripe regions 32. If not yet completed, the process returns to the writing position deviation amount calculation step (S120) and repeats the writing position deviation amount calculation step (S120) to the determination step (S124) for the next stripe region 32. In this manner, the writing position deviation amount calculation step (S120) to the determination step (S124) are repeated until writing of all stripe regions 32 is completed.

[0124] As a first correction amount map creation step (S126), the correction amount map creation unit 58 creates a first correction amount map for the entire surface of the sample 101, in which the element values ​​are the correction amounts (dx1stn, dy1stn) for the first rendering process for each global mesh region 11 (xn, yn). The first correction amount map is stored in the storage device 142.

[0125] As a writing positional deviation amount (vector B2) calculation step (S130), the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (third positional deviation amount) from a designed position caused by irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before the irradiation time of the electron beam in the second writing process. In other words, the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (third positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position caused by an electron beam irradiated in the second writing process corresponding to a target electron beam in the first writing process, caused by irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before the irradiation of the electron beam in the second writing process corresponding to the target electron beam in the first writing process. Specifically, the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (vector B2) of a representative position in each global mesh region 11. The vector B2 of each global mesh region 11 is calculated as the amount of misalignment during writing (dx2ndwrite-n, dy2ndwrite-n), where n indicates the index of each global mesh region 11. The amount of misalignment during writing of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the amount of misalignment during writing of the pattern formation position or beam irradiation position. The amount of misalignment during writing (dx2ndwrite-n, dy2ndwrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, using the finite element method, as described above.

[0126] As described above, it is also preferable to calculate the amount of positional deviation during writing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0127] In the correction amount calculation step (S132), the correction amount calculation unit 64 calculates a correction amount (vector B2-vector C2) (second correction amount) for correcting a pattern formation position or a beam irradiation position when the sample 101 is irradiated with an electron beam (multi-beam 20) in the second writing process corresponding to the target electron beam in the first writing process, based on a final positional deviation amount due to irreversible deformation of the sample 101 after writing is completed. The correction amount (vector B2-vector C2) (second correction amount) is calculated based on the difference between the writing positional deviation amount (vector B2) and the final positional deviation amount (vector C2) in the second writing process. In other words, the correction amount calculation unit 64 calculates the second correction amount in the second writing process based on the difference between the writing positional deviation amount and the final positional deviation amount in the second writing process. In other words, the correction amount (dx2ndn, dy2ndn) of each position within the global mesh region 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the amount of positional deviation at the time of drawing (dx2ndwrite-n, dy2ndwrite-n) from the final amount of positional deviation (dxfinal-n, dyfinal-n).

[0128] In the determination step (S134), the writing control unit 76 determines whether calculation of the correction amount for the second writing process has been completed for all stripe regions 32. If not yet completed, the process returns to the writing position deviation amount calculation step (S130) and repeats the writing position deviation amount calculation step (S130) to the determination step (S134) for the next stripe region 32. In this manner, the writing position deviation amount calculation step (S130) to the determination step (S134) are repeated until writing for all stripe regions 32 for the second writing process is completed.

[0129] As a second correction amount map creation step (S136), the correction amount map creation unit 66 creates a second correction amount map for the entire surface of the sample 101, in which the element values ​​are the correction amounts (dx2ndn, dy2ndn) for the second drawing process for each global mesh region 11 (xn, yn). The second correction amount map is stored in the storage device 142.

[0130] In the first writing step (S174), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose amount) for irradiating the pixel 36 for the first writing process. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as is.

[0131] Next, the shot data generation unit 70 calculates the irradiation time for the first drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0132] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the first drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0133] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx1stn, dy1stn). In other words, the drawing mechanism 150 performs the first correction in the first drawing process based on the difference between the positional deviation amount at the time of drawing in the first drawing process and the final positional deviation amount. The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx1stn, dy1stn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the central beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the central beam).

[0134] In the second writing process (S176), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose) for irradiating the pixel 36 for the second writing process. In other words, the incident irradiation amount D(x) (dose) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose) is defined in the dose map, it may be used as is.

[0135] Next, the shot data generation unit 70 calculates the irradiation time for the second drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0136] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the second drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0137] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx2ndn, dy2ndn). In other words, the drawing mechanism 150 performs the second correction in the second drawing process based on the difference between the positional deviation amount at the time of drawing in the second drawing process and the final positional deviation amount. The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx2ndn, dy2ndn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the center beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the center beam).

[0138] In the modification of the second embodiment, similarly to the modification of the first embodiment, the formation position of the pattern may be corrected on the pattern data.

[0139] In the modification of the second embodiment, in the first writing process (S174), the shot data generation unit 70 first corrects the formation position of the pattern on the writing data based on a first correction amount map having the correction amount (dx1stn, dy1stn) for the first writing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0140] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0141] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0142] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the first writing process. In the modified example of the second embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx1stn, dy1stn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, the center position or the position of the center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) for example four pixels 36 at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0143] Similarly, in the second drawing process (S176), the shot data generation unit 70 first corrects the formation position of the pattern on the drawing data based on a second correction amount map having the correction amount (dx2ndn, dy2ndn) for the second drawing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0144] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0145] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0146] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the second writing process. In the modified example of the second embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx2ndn, dy2ndn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, a center position or a position of a center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) four pixels 36, for example, at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0147] As described above, according to the second embodiment, it is possible to correct positional deviations of the beam irradiation position and the pattern formation position in two-stroke writing caused by irreversible deformation of the sample 101 due to irradiation with the multibeams 20 (electron beams).

[0148] Embodiment 3 In the third embodiment, for the two-stroke drawing described in the second embodiment, a case is explained in which, when the first drawing process is performed without correction, the second drawing process is performed in accordance with the position drawn in the first drawing process. The configuration of the imaging device 100 in the third embodiment is similar to that in FIG. 18, except that the final positional deviation amount calculation unit 52, the correction amount calculation unit 56, and the correction amount map creation unit 58 are omitted.

[0149] FIG. 23 is a diagram showing an example of a state of misalignment on the substrate surface according to the third embodiment. Figure 23 shows the state before the start of the first drawing process, the state when drawing at the desired position in the first drawing process, the state after the first drawing process is completed, the state when drawing at the desired position in the second drawing process, and the state after the second drawing process is completed.

[0150] In Fig. 23, the designed beam irradiation position is indicated by vector A. If, in the first drawing process for the target LTEM substrate, the position of vector A before the start of the drawing process is drawn as is without any correction, then at the time when the position of vector A is drawn in the second drawing process, the position of vector A before the start of the drawing process will have physically moved to a position (vector A+(vector B2-vector B1)) that is moved by the vector indicated by (vector B2-vector B1) from the position of vector A before the start of the drawing process due to deformation caused by contraction of the substrate, as shown in Fig. 23.

[0151] In the third embodiment, the second writing process is performed with the same layout pattern as the first writing process, so that the second writing process also performs writing on the beam irradiation position in the first writing process. Therefore, when drawing in the second drawing process, a position (vector A+(vector B2-vector B1)) obtained by correcting the position of vector A before the start of the process by the vector indicated by (vector B2-vector B1) is drawn as the beam irradiation position (or pattern formation position). As a result, after the drawing process of the entire substrate after the second drawing process is completed, the beam irradiation position (or pattern formation position) drawn in the first drawing process and the beam irradiation position (or pattern formation position) drawn in the second drawing process can be at the same position, although they are different from the position of vector A before the start of the process.

[0152] A flowchart showing an example of the main steps of the writing method in the third embodiment is the same as that in Fig. 22, except that the final positional deviation amount (vector C2) calculation step (S105), the correction amount calculation step (S122), the determination step (S124), and the first correction amount map creation step (S126) are omitted. In the third embodiment, no correction is made in the first writing process, and therefore no calculation of the correction amount is performed in the first writing process.

[0153] The contents of the dose map creation process (S103), the drawing schedule creation process (S107), and the drawing position deviation amount (vector B1) calculation process (S120) in embodiment 3 are similar to those described in the dose map creation process (S103), the drawing schedule creation process (S107), and the drawing position deviation amount (vector B1) calculation process (S120) in Figure 22. In other words, in the writing positional deviation amount (vector B1) calculation step (S120), the writing positional deviation amount calculation unit 54 calculates a positional deviation amount (another example of a first positional deviation amount) of a pattern formation position or a beam irradiation position from a design position at the time of irradiation of a target electron beam due to irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before irradiation of the target electron beam irradiated to the pattern formation position or the beam irradiation position in the first writing process, in a case where a first writing process and a second writing process performed after the first writing process are performed using an electron beam on the sample 101 that is irreversibly deformed by irradiation of the electron beam. Specifically, the writing positional deviation amount calculation unit 54 calculates a positional deviation amount (vector B1) at the time of writing of a representative position in each global mesh region 11. The vector B1 of each global mesh region 11 is calculated as a writing positional deviation amount (dx1stwrite-n, dy1stwrite-n). n indicates an index of each global mesh region 11. The amount of misregistration during writing of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the amount of misregistration during writing of the pattern formation position or beam irradiation position. The amount of misregistration during writing (dx1stwrite-n, dy1stwrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, by using the finite element method, as described above.

[0154] In the above example, the amount of misregistration during drawing is calculated for each global mesh region 11, but the present invention is not limited to this. It is also preferable to calculate the amount of misregistration during drawing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0155] The contents of the drawing positional deviation amount (vector B2) calculation step (S130) in the third embodiment are similar to those described in the drawing positional deviation amount (vector B2) calculation step (S130) in FIG.

[0156] In the correction amount calculation step (S132), the correction amount calculation unit 64 calculates a correction amount (vector B2-vector B1) (another example of the first correction amount) for correcting the pattern formation position or beam irradiation position at the time of irradiation with the electron beam in the second writing process corresponding to the target electron beam in the first writing process, based on the positional deviation amount (vector B1). The correction amount (vector B2-vector B1) (another example of the first correction amount) is calculated based on the difference between the writing positional deviation amount (vector B2) of the second writing process and the writing positional deviation amount (vector B1) of the first writing process. In other words, the correction amount (dx2ndn, dy2ndn) of each position in the global mesh region 11 that is irradiated (written) with the beam for the nth time can be calculated by the writing positional deviation amount (dx2ndwrite-n, dy2ndwrite-n)-writing positional deviation amount (dx1stwrite-n, dy1stwrite-n).

[0157] The contents of the determination step (S134) and the second correction amount map creation step (S136) in the third embodiment are similar to those described in the determination step (S134) and the second correction amount map creation step (S136) in FIG.

[0158] In the first writing step (S174), the shot data generation unit 70 uses the dose map for the first writing process to calculate the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0159] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0160] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) as a first writing process. In the third embodiment, in both the real-time mode and the pre-processing mode, under the control of the deflection control circuit 130, when writing, the deflector 208 deflects the beam array to a design position for a representative position (for example, a center position or a position of a center beam) of the beam array for each tracking cycle, and while each beam writes (exposes) for example, four pixels 36 at that position during the tracking cycle, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation region 34) does not shift in relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation region 34) follow the movement of the XY stage 105.

[0161] In the second writing step (S176), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose amount) for irradiating the pixel 36 for the second writing process. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as is.

[0162] Next, the shot data generation unit 70 calculates the irradiation time for the second drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0163] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the second drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0164] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx2ndn, dy2ndn). The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx2ndn, dy2ndn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the central beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the central beam).

[0165] In the modification of the third embodiment, similarly to the modification of the second embodiment, the formation position of the pattern may be corrected on the pattern data.

[0166] The content of the first writing step (S174) in the modification of the third embodiment is similar to that of the first writing step (S174) in the third embodiment.

[0167] In the second drawing process (S176) in the modified example of the third embodiment, the shot data generation unit 70 first corrects the formation position of the pattern on the drawing data based on a correction amount map having the correction amount (dx2ndn, dy2ndn) for the second drawing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0168] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0169] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0170] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the second writing process. In the modified example of the third embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx2ndn, dy2ndn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, the center position or the position of the center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) four pixels 36, for example, at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0171] As described above, according to the third embodiment, even if the positional deviation of the beam irradiation position or the pattern formation position in the first stroke of two-stroke writing is not corrected, the positional deviation of the beam irradiation position or the pattern formation position due to the irreversible deformation of the sample 101 caused by the irradiation of the multi-beam 20 (electron beam) can be corrected in the second stroke.

[0172] Embodiment 4 In embodiment 4, a case is described in which, after the first drawing process of the entire drawing area (chip area) of sample 101 has been completed, sample 101 is removed and development, etching, resist coating, etc. are performed, and then sample 101 is placed back on stage 105 and overlapping drawing is performed to perform a second drawing process of the entire drawing area (chip area) of sample 101 using a different layout pattern.

[0173] Fig. 24 is a conceptual diagram showing the configuration of a writing device in embodiment 4. In Fig. 24, a mark shift amount calculation unit 67, a GMC (Grid Matching Correction) correction unit 68, and a mark position correction unit 69 are further arranged in a control computer 110, a detection circuit 137 is further arranged, and a detector 212 is further arranged in an electron lens barrel 102. Other than this, the configuration is the same as that in Fig. 18.

[0174] Each of the "~" units, such as the dose map creation unit 50, the final positional deviation amount calculation unit 52, the writing positional deviation amount calculation unit 54, the correction amount calculation unit 56, the correction amount map creation unit 58, the writing positional deviation amount calculation unit 62, the correction amount calculation unit 64, the correction amount map creation unit 66, the mark deviation amount calculation unit 67, the GMC correction unit 68, the mark position correction unit 69, the shot data generation unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76, has a processing circuit. Such a processing circuit includes, for example, an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. Each of the "~" units may use a common processing circuit (the same processing circuit) or may use different processing circuits (separate processing circuits). Information input to and output from the dose map creation unit 50, the final positional deviation amount calculation unit 52, the writing positional deviation amount calculation unit 54, the correction amount calculation unit 56, the correction amount map creation unit 58, the writing positional deviation amount calculation unit 62, the correction amount calculation unit 64, the correction amount map creation unit 66, the mark deviation amount calculation unit 67, the GMC correction unit 68, the mark position correction unit 69, the shot data generation unit 70, the data processing unit 72, the transfer processing unit 74, and the writing control unit 76, as well as information being calculated, are stored in the memory 112 each time. As in the second embodiment, one of the writing positional deviation amount calculation unit 54 and the writing positional deviation amount calculation unit 62 may be configured to have the functions of both. In that case, the other may be omitted.

[0175] In the first drawing process, drawing is performed in sequence from the lower stripe region 32 of the sample 101 toward the upper side (y direction) as in Fig. 19. After the first drawing process of the entire drawing region (chip region) of the sample 101 is completed, the sample 101 is taken out of the drawing apparatus 100, and is developed, etched, resist-coated, and so on. Then, in a state where it is placed back on the stage 105, a second drawing process is performed in which drawing data of a different pattern layout is used to draw the pattern layout that has already been drawn, as shown in the right diagram of Fig. 19. The right diagram of Fig. 19 shows a state where a certain position (indicated by x: a position that is paired with the position indicated by x in the diagram on the left) is drawn during the second drawing process.

[0176] FIG. 25 is a diagram showing an example of a state of misalignment on the substrate surface in a comparative example of the fourth embodiment. In FIG. Figure 25 shows the state before the start of the first drawing process, the state when drawing at the desired position in the first drawing process, the state after the first drawing process is completed, the state when drawing at the desired position in the second drawing process, and the state after the second drawing process is completed.

[0177] In Fig. 25, the designed beam irradiation position in the first writing process is indicated by vector A11. The designed beam irradiation position in the second writing process is indicated by vector A21. As the first writing process progresses on the target LTEM substrate, by the time the position of vector A11 is written in the first writing process, the position of vector A11 before the writing process starts has physically moved to the position of vector B11 due to deformation caused by shrinkage of the substrate as shown in Fig. 25. Similarly, the position of vector A21 before the writing process starts has physically moved to the position of vector B21 due to deformation caused by shrinkage of the substrate as shown in Fig. 25.

[0178] Then, as the rendering process progresses further, after the first rendering process is completed, the position of vector A11 before the start of the rendering process has physically moved to the position of vector C11 due to further deformation, as shown in Figure 25. Similarly, the position of vector A21 before the start of the rendering process has physically moved to the position of vector C21.

[0179] Then, the second drawing process is started, the drawing process progresses, and by the time the position of vector A21 is drawn in the second drawing process, the position of vector A11 before the start of the drawing process has physically moved to the position of vector B12 due to deformation caused by contraction of the board, as shown in Figure 25. Similarly, the position of vector A21 before the start of the drawing process has physically moved to the position of vector B22.

[0180] Then, as the drawing process progresses further, after the second drawing process is completed (after the drawing process for the entire board is completed), the position of vector A11 before the start of the drawing process has physically moved to the position of vector C12 due to further deformation, as shown in Figure 25. Similarly, the position of vector A21 before the start of the drawing process has physically moved to the position of vector C22.

[0181] Therefore, if the position of vector A11 before the start of drawing processing is drawn as it is in the first drawing process, after the drawing processing of the entire substrate is completed, the drawn beam irradiation position will be shifted to a position (vector A+(vector C12-vector B11)) moved by the vector indicated by (vector C12-vector B11) from the position of vector A11 before the start of drawing processing. Similarly, if the position of vector A21 before the start of drawing processing is drawn as it is in the second drawing process, after the drawing processing of the entire substrate is completed, the drawn beam irradiation position will be shifted to a position (vector A21+(vector C12-vector B12)) moved by the vector indicated by (vector C12-vector B12) from the position of vector A21 before the start of drawing processing. Therefore, in embodiment 4, even if such irreversible deformation occurs in the substrate, the irradiation position during drawing (pattern formation position) is corrected so that after the drawing process is completed, the beam irradiation position of the first drawing process becomes the position of vector A11 before the drawing process starts, and the beam irradiation position of the second drawing process becomes the position of vector A21 before the drawing process starts.

[0182] Fig. 26 is a diagram showing an example of a state of positional deviation on the substrate surface in the fourth embodiment. The state of deformation on the substrate surface in the fourth embodiment is not shown. In Fig. 26, the designed beam irradiation position in the first writing process is indicated by vector A11. The designed beam irradiation position in the second writing process is indicated by vector A21.

[0183] As the first writing process proceeds on the target LTEM substrate, by the time the position of vector A11 is written in the first writing process, the position of vector A11 before the writing process starts has physically moved to the position of vector B11 due to deformation caused by shrinkage of the substrate, as shown in Figure 26. Similarly, the position of vector A21 before the writing process starts has physically moved to the position of vector B21 due to deformation caused by shrinkage of the substrate, as shown in Figure 26.

[0184] Then, after the first drawing process is completed and then the second drawing process is completed, the position of vector A11 before the start of the drawing process is physically moved to the position of vector C12 due to further deformation as shown in Figure 26. Similarly, the position of vector A21 before the start of the drawing process is physically moved to the position of vector C22.

[0185] Therefore, when drawing in the first drawing process, it is sufficient to correct only the positional deviation amount (vector C12-vector B11) from the position at that time (vector B11) to the position after the drawing process of the entire substrate is completed (vector C12). Therefore, when drawing in the first drawing process, a position (vector A11+(vector B11-vector C12)) corrected by the vector indicated by (vector B11-vector C12) from the position of vector A11 before the process starts is drawn as the beam irradiation position (or pattern formation position). As a result, after the drawing process of the entire substrate is completed after the second drawing process, the beam irradiation position (or pattern formation position) drawn in the first drawing process can be the position of vector A11, which is the position moved by the vector indicated by (vector C12-vector B11) from the position (vector A11+(vector B11-vector C12)).

[0186] Then, when the position of vector A21 is drawn in the second drawing process, the position of vector A21 before the start of the drawing process has physically moved to the position of vector B22 due to deformation caused by contraction of the board, as shown in Fig. 26. This is the same as the amount of positional deviation (vector B12 - vector A11) by which the position of vector A11 before the start of the process has moved to the position of vector B12. After the second drawing process is completed and the drawing process is completed for the entire substrate, the position of vector A21 before the start of drawing process has physically moved to the position of vector C22 as described above. This is the same as the amount of positional deviation (vector C12-vector A11) that occurs when the position of vector A11 before the start of processing has moved to the position of vector C12.

[0187] Therefore, when writing in the second writing process, it is sufficient to correct only the positional deviation amount (vector C22-vector B22) from the position at that time (vector B22) to the position after the writing process of the entire substrate is completed (vector C22). This is the same as the positional deviation amount (vector C12-vector B12) from the position (vector B12) to the position after the writing process of the entire substrate is completed (vector C12). Therefore, when writing in the second writing process, the position (vector A21+(vector B12-vector C12)) corrected by the vector indicated by (vector B12-vector C12) from the position of vector A21 before the process starts is written as the beam irradiation position (or pattern formation position). As a result, after the second drawing process has been completed for the entire substrate, the beam irradiation position (or pattern formation position) drawn in the second drawing process can be located at the position of vector A21, which is a position moved from the position (vector A21 + (vector B12 - vector C12)) by the vector indicated by (vector C12 - vector B12).

[0188] As a result, the beam irradiation position drawn in the first drawing process and the beam irradiation position drawn in the second drawing process can be both located at the positions of vectors A11 and A21 before the start of the drawing process after the drawing process of the entire substrate is completed, and the relative positional relationship between them can be maintained.

[0189] FIG. 27 is a flow chart showing an example of some of the main steps of the writing method according to the fourth embodiment. FIG. 28 is a flow chart showing the remaining steps of the example of the main steps of the writing method according to the fourth embodiment. 27 and 28, the writing method in the fourth embodiment includes a dose map creating step (S101), a final positional deviation amount (vector C2) calculating step (S103), a writing schedule creating step (S107), a writing positional deviation amount (vector B11) calculating step (S121), a correction amount calculating step (S123), a determination step (S124), a first correction amount map creating step (S127), a writing positional deviation amount (vector B12) calculating step (S131), and a correction amount calculating step (S133). A series of steps are performed, including a determination step (S134), a second correction amount map creation step (S137), a first mark measurement step (S180), a first GMC correction step (S182), a first writing step (S184), a development / etching / resist application step (S186), a mark shift amount calculation step (S188), a second mark measurement step (S190), a mark position correction step (S192), a second GMC correction step (S194), and a second writing step (S196). The writing process in the fourth embodiment includes a first writing process for writing a first chip pattern, and a second writing process that is performed after the first writing process and writes a second chip pattern so as to overlap the first chip pattern. The second chip pattern in the fourth embodiment is different from the first chip pattern.

[0190] 27 and 28 show flowcharts for performing drawing processing in a preprocessing mode in which a drawing operation is started after a calculation process for correcting the beam irradiation position (or the pattern formation position) of all regions is performed as a preprocessing. A flowchart for performing drawing processing in a real-time mode in which a calculation process for correcting the beam irradiation position (or the pattern formation position) of the next region is performed while a drawing operation is being performed is omitted.

[0191] In the real-time mode, after the first mark measurement step (S180) and the first GMC correction step (S182) are performed, the writing operation of the kth stripe region in the first writing process and the correction calculation process (writing position deviation amount (vector B11) calculation step (S121), correction amount calculation step (S123), judgment step (S124), and first correction amount map creation step (S127)) of the k+mth stripe region are performed simultaneously. Then, the first writing step (S194) is sequentially performed for the stripe regions 32 for which the correction calculation process has been completed. Thereafter, a developing / etching / resist coating step (S186), a mark shift amount calculation step (S188), a second mark measurement step (S190), a mark position correction step (S192), and a second GMC correction step (S194) are performed, and then the drawing operation of the kth stripe region in the second drawing process and the correction calculation process of the k+mth stripe region (drawing position shift amount (vector B12) calculation step (S131), correction amount calculation step (S133), judgment step (S134), and second correction amount map creation step (S136)) are performed simultaneously. Then, the second drawing process (S196) is performed sequentially for the stripe regions 32 for which the correction calculation process has been completed.

[0192] In the dose map creating step (S101), the dose map creating unit 50 creates a dose map in which the dose amount is defined for each pixel. Here, a dose map for the first drawing process (first dose map) and a dose map for the second drawing process (second dose map) are created. The method of creating the dose map may be the same as the content of the dose map creating step (S102) described above.

[0193] In a final positional deviation amount (vector C12) calculation step (S103), the final positional deviation amount calculation unit 52 calculates a final positional deviation amount (first positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position due to irreversible deformation of the sample 101 after writing is completed when a pattern is written using an electron beam on the sample 101 that is irreversibly deformed by irradiation with the electron beam. Specifically, the final positional deviation amount calculation unit 52 calculates a positional deviation amount (vector C12) of each position after the first writing process and the second writing process are completed and the writing process on the sample 101 is completed.

[0194] Then, the final positional deviation calculation unit 52 calculates a vector C12 at a representative point (e.g., a central position) in each global mesh region 11 (position). Each vector C12 is calculated as a final positional deviation (dxfinal-i, dyfinal-i), where i indicates the index of each global mesh region 11. The final positional deviation of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the final positional deviation of the pattern formation position or beam irradiation position. The final positional deviation amount (dxfinal-i, dyfinal-i) of each global mesh region 11 depends on the irradiation dose (irradiation coefficient) defined in the dose map, and can be calculated, for example, using the finite element method, as described above.

[0195] In the writing schedule creation step (S107), the writing control unit 76 creates a writing schedule that defines the shot order of each pixel defined in the dose map. Here, a writing schedule is created for each of the first writing process and the second writing process. This makes it possible to know the irradiated position and the irradiation amount for each shot up to the time when the shot is performed (at the time of writing).

[0196] As a writing positional deviation amount (vector B11) calculation step (S121), the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) from a designed position caused by irreversible deformation of the sample 101 caused by the electron beam irradiated to the sample 101 before the irradiation time of the electron beam at the time of irradiation of the electron beam in the first writing process. In other words, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (second positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position at the time of irradiation of the electron beam of the target caused by irreversible deformation of the sample 101 caused by the electron beam irradiated to the sample 101 before the irradiation of the electron beam of the target irradiated to the pattern formation position or the beam irradiation position in the first writing process. Specifically, the writing positional deviation amount calculation unit 54 calculates a writing positional deviation amount (vector B11) of a representative position in each global mesh region 11. A vector B11 of each global mesh region 11 is calculated as a positional deviation amount at the time of writing (dx1stwrite-n, dy1stwrite-n), where n indicates an index of each global mesh region 11. The positional deviation amount at the time of writing of a global mesh region 11 including a pattern formation position or a beam irradiation position corresponds to the positional deviation amount at the time of writing of the pattern formation position or the beam irradiation position. The positional deviation amount at the time of writing (dx1stwrite-n, dy1stwrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, by using the finite element method, as described above.

[0197] In the above example, the amount of misregistration during drawing is calculated for each global mesh region 11, but the present invention is not limited to this. It is also preferable to calculate the amount of misregistration during drawing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0198] In the correction amount calculation step (S123), the correction amount calculation unit 56 calculates a correction amount (vector B11-vector C12) (first correction amount) for correcting a pattern formation position or a beam irradiation position when the sample 101 is irradiated with a target electron beam (multi-beam 20) based on a final positional deviation amount due to irreversible deformation of the sample 101 after writing is completed. The correction amount (vector B11-vector C12) (first correction amount) is calculated based on a difference between a positional deviation amount at the time of writing (vector B11) of the first writing process and a final positional deviation amount (vector C12). In other words, the correction amount calculation unit 56 calculates the first correction amount in the first writing process based on a difference between a positional deviation amount at the time of writing of the first writing process and a final positional deviation amount. In other words, the correction amount (dx1stn, dy1stn) of each position within the global mesh region 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the positional deviation amount at the time of drawing (dx1stwrite-n, dy1stwrite-n) from the final positional deviation amount (dxfinal-n, dyfinal-n).

[0199] In the determination step (S124), the writing control unit 76 determines whether calculation of the correction amount for the first writing process has been completed for all stripe regions 32. If not yet completed, the process returns to the writing misalignment amount calculation step (S121) and repeats the writing misalignment amount calculation step (S121) through the determination step (S124) for the next stripe region 32. In this manner, the writing misalignment amount calculation step (S120) through the determination step (S124) are repeated until writing is completed for all stripe regions 32.

[0200] As a first correction amount map creation step (S127), the correction amount map creation unit 58 creates a first correction amount map for the entire surface of the sample 101, in which the element values ​​are the correction amounts (dx1stn, dy1stn) for the first drawing process for each global mesh region (xn, yn). The first correction amount map is stored in the storage device 142.

[0201] As a writing positional deviation amount (vector B12) calculation step (S131), the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (third positional deviation amount) from a designed position caused by irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before the irradiation time of the electron beam in the second writing process at the time of irradiation of the electron beam. In other words, the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (third positional deviation amount) of a pattern formation position or a beam irradiation position from a designed position at the time of irradiation of the electron beam in the second writing process corresponding to the target electron beam in the first writing process caused by irreversible deformation of the sample 101 caused by an electron beam irradiated to the sample 101 before irradiation of the electron beam in the second writing process corresponding to (paired with) the target electron beam in the first writing process. Specifically, the writing positional deviation amount calculation unit 62 calculates a writing positional deviation amount (vector B12) of a representative position in each global mesh region 11. The vector B12 of each global mesh region 11 is calculated as the amount of misalignment during writing (dx2ndwrite-n, dy2ndwrite-n), where n indicates the index of each global mesh region 11. The amount of misalignment during writing of the global mesh region 11 including the pattern formation position or beam irradiation position corresponds to the amount of misalignment during writing of the pattern formation position or beam irradiation position. The amount of misalignment during writing (dx2ndwrite-n, dy2ndwrite-n) of each global mesh region 11 depends on the dose (irradiation coefficient) defined in the dose map, and can be calculated in the same manner, for example, using the finite element method, as described above.

[0202] As described above, it is also preferable to calculate the amount of positional deviation during writing for each representative position (for example, the center position or the position of the center beam) of the beam array during an actual shot.

[0203] In the correction amount calculation step (S133), the correction amount calculation unit 64 calculates a correction amount (vector B12-vector C12) (second correction amount) for correcting a pattern formation position or a beam irradiation position when the sample 101 is irradiated with an electron beam (multi-beam 20) in the second writing process corresponding to (paired with) the target electron beam in the first writing process, based on a final positional deviation amount due to irreversible deformation of the sample 101 after writing is completed. The correction amount (vector B12-vector C12) (second correction amount) is calculated based on the difference between the writing positional deviation amount (vector B12) and the final positional deviation amount (vector C12) in the second writing process. In other words, the correction amount calculation unit 64 calculates the second correction amount in the second writing process based on the difference between the writing positional deviation amount and the final positional deviation amount in the second writing process. In other words, the correction amount (dx2ndn, dy2ndn) of each position within the global mesh region 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the amount of positional deviation at the time of drawing (dx2ndwrite-n, dy2ndwrite-n) from the final amount of positional deviation (dxfinal-n, dyfinal-n).

[0204] In the determination step (S134), the writing control unit 76 determines whether calculation of the correction amount for the second writing process has been completed for all stripe regions 32. If not yet completed, the process returns to the writing position deviation amount calculation step (S131) ​​and repeats the writing position deviation amount calculation step (S131) ​​to the determination step (S134) for the next stripe region 32. In this manner, the writing position deviation amount calculation step (S131) ​​to the determination step (S134) are repeated until writing is completed for all stripe regions 32 for the second writing process.

[0205] As a second correction amount map creation step (S137), the correction amount map creation unit 66 creates a second correction amount map for the entire surface of the sample 101, in which the element values ​​are the correction amounts (dx2ndn, dy2ndn) for the second drawing process for each global mesh region (xn, yn). The second correction amount map is stored in the storage device 142.

[0206] In the first mark measurement step (S180), before the first drawing process, the mark position (first mark position) of the alignment mark 14 is measured. Specifically, the sample 101 is carried into the drawing apparatus 100, and in a state in which the sample 101 is placed on the stage 103, the mark positions of the alignment marks 14 formed, for example, at the four corners of the sample 101 are measured.

[0207] FIG. 29 is a diagram showing an example of a sample surface on which alignment marks are formed in the fourth embodiment. In FIG. 29, an alignment mark 14 for alignment is formed in advance on the sample 101. For example, a plurality of alignment marks 14 are formed. As each alignment mark 14, for example, a cross pattern is preferably formed as shown in FIG. 29. In the example of FIG. 29, a chip region for forming a pattern is provided in the center of the sample 101 surface. Then, the alignment marks 14 are formed, for example, at each of the four corners on the sample 101 surface. Under the control of the drawing control unit 76, the drawing mechanism 150 scans each alignment mark 14 with an electron beam, and the detector 212 detects secondary electrons emitted from the sample 101 surface including the alignment marks 14. The intensity data detected by the detector 212 is output to the detection circuit 137. The detection circuit 137 converts the analog data into digital data, amplifies it, and outputs it to the control computer 110.

[0208] In the first GMC correction step (S182), the GMC correction unit 68 performs grid matching correction on the pattern data based on the measured positions of each alignment mark 14. For example, the lower left mark position of the sample 101 is set as the origin, and an x-axis connecting the origin and the lower right mark position and a y-axis connecting the origin and the upper left mark position are set. The position of the chip pattern (first chip pattern) to be written on the sample 101 during the first writing process is defined based on the measured mark position (first mark position). Therefore, the GMC correction unit 68 corrects the pattern data so that the coordinate system of the pattern data defined in the writing data is aligned with the x-axis and y-axis. As a result, each pattern data can be translated, rotated, and reduced / enlarged based on the origin obtained from the multiple alignment marks 14. The method of data conversion may be the same as that of a conventional method, and therefore will not be described.

[0209] In overlay writing, the relative positional relationship between the pattern written in the first writing process and the pattern written in the second writing process is important. Meanwhile, the sample 101 is removed from the stage 103 between the first writing process and the second writing process. Therefore, the sample 101 is not necessarily placed at exactly the same position on the stage 103 in the first writing process and the second writing process. Therefore, the pattern formation position in the first writing process and the pattern formation position in the second writing process are aligned based on the mark position.

[0210] In each of the above-mentioned embodiments, it is preferable to perform mark measurement and GMC correction, so that a pattern can be written based on the mark position on the surface of the sample 101.

[0211] In the first writing step (S184), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose amount) for irradiating the pixel 36 for the first writing process. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as is.

[0212] Next, the shot data generation unit 70 calculates the irradiation time for the first drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0213] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the first drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0214] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx1stn, dy1stn). In other words, the drawing mechanism 150 performs the second correction in the first drawing process based on the difference between the positional deviation amount at the time of drawing in the first drawing process and the final positional deviation amount. The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx1stn, dy1stn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the central beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the central beam).

[0215] In the developing / etching / resist coating step (S186), the sample 101 is carried out from the drawing apparatus 100, and developing / etching / resist coating are performed. As a result, the pattern drawn in the first drawing process is formed on the surface of the sample 101. For example, the sample 101 has a light-shielding film of chromium (Cr) or the like formed on a glass substrate, and a resist film is applied on the light-shielding film. In the first drawing process, a chip pattern in the first drawing process (first chip pattern) is drawn on the resist film. Then, a resist pattern according to the chip pattern is formed by development, and the chip pattern on the light-shielding film is formed by etching and the subsequent ashing. Subsequently, in order to perform the second drawing process, a resist film is applied to the sample 101 again, and the sample 101 is carried into the drawing apparatus 100 and placed on the stage 103.

[0216] FIG. 30 is a diagram showing an example of a mark position after the first drawing process in the fourth embodiment. Fig. 31 is a diagram showing an example of the mark positions after the second writing process in the fourth embodiment. The sample 101 is irreversibly deformed by the first writing process as shown in Fig. 30. Then, the sample 101 is further irreversibly deformed by the second writing process as shown in Fig. 31. Therefore, the physical positions of the alignment marks 14 on the sample 101 are shifted by the first writing process and the second writing process.

[0217] In the mark shift amount calculation step (S188), the mark shift amount calculation unit 67 calculates the amount of positional shift of the mark position from the mark position (first mark position) before the start of the first writing process due to irreversible deformation of the sample 101 after the end of the first writing process. Specifically, the mark shift amount calculation unit 67 calculates the amount of positional shift (mark shift amount) of a representative position in the global mesh region 11 including each of the alignment marks 14 at a timing after the end of the first writing process and before the start of the second writing process. The amount of positional shift of each global mesh region 11 including each of the alignment marks 14 is calculated as the mark shift amount (dxmark-n, dymark-n). n indicates the index of each global mesh region 11. The mark shift amount (dxmark-n, dymark-n) after the first drawing process of the global mesh region 11 including each of the alignment marks 14 depends on the dose (exposure coefficient) defined in the dose map, and can be calculated in the same manner as described above, for example, by using the finite element method. The data of the calculated mark shift amount (dxmark-n, dymark-n) is stored in the storage device 142.

[0218] The developing / etching / resist coating step (S186) and the mark shift amount calculation step (S188) may be performed in any order, or may be performed simultaneously.

[0219] In a second mark measurement step (S190), the sample 101 is temporarily removed from the stage 103, and in a state in which the sample 101 is placed again on the stage 103 for the second writing process, the mark position (second mark position) of the alignment mark 14 is measured before the start of the second writing process. The method of measuring the mark position may be the same as in the first mark measurement step (S180).

[0220] The data of the chip pattern drawn in the first writing process and the data of the chip pattern drawn in the second writing process are created on the assumption that there is no irreversible deformation of the sample 101 due to beam irradiation. Therefore, when the chip pattern drawn in the second writing process is written based on the mark positions measured in the second mark measurement step (S190), the relative positions of the pattern drawn in the first writing process and the pattern drawn in the second writing process are shifted by the amount of positional deviation due to the irreversible deformation of the sample 101. Therefore, in the fourth embodiment, the mark positions serving as the reference in the second writing process are corrected for the amount of positional deviation due to the irreversible deformation of the sample 101 from the measurement results. This will be described below.

[0221] In the mark position correction step (S192), the mark position correction unit 69 calculates a mark position (third mark position) obtained by correcting the mark shift amount (dxmark-n, dymark-n) which is the amount of positional shift of the mark position from the measured mark position (second mark position) before the start of the second drawing process. Since the sample 101 is once removed from the position on the stage 103 of the sample 101 in the first mark measurement step (S180) and the position on the stage 103 of the sample 101 in the second mark measurement step (S190), a positional shift different from the positional shift due to the irreversible deformation of the sample 101 due to the first drawing process is further generated. Therefore, the mark position correction step (S192) can correct the amount of positional shift of the alignment mark 14 due to the irreversible deformation of the sample 101 due to the first drawing process from the mark position measured in the second mark measurement step (S190).

[0222] As a second GMC correction step (S194), the GMC correction unit 68 performs grid matching correction on the pattern data based on the corrected positions (third mark positions) of each alignment mark 14. For example, the lower left mark position of the sample 101 is set as the origin, and an x-axis connecting the origin and the lower right mark position and a y-axis connecting the origin and the upper left mark position are set. The position of the chip pattern (second chip pattern) to be written on the sample 101 during the second writing process is defined based on the corrected mark position (third mark position). Therefore, the GMC correction unit 68 corrects the pattern data so that the coordinate system of the pattern data defined in the writing data is aligned with the x-axis and y-axis. As a result, each pattern data can be translated, rotated, and reduced / enlarged based on the origin obtained from the corrected alignment marks 14. The method of data conversion may be the same as that of a conventional method, and therefore will not be described.

[0223] In the second writing process (S196), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose amount) for irradiating the pixel 36 for the second writing process. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as is.

[0224] Next, the shot data generation unit 70 calculates the irradiation time for the second drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0225] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the second drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0226] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx2ndn, dy2ndn). In other words, the drawing mechanism 150 performs the second correction in the second drawing process based on the difference between the positional deviation amount at the time of drawing in the second drawing process and the final positional deviation amount. The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx2ndn, dy2ndn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the center beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the center beam).

[0227] In the modification of the fourth embodiment, similarly to the modification of the second embodiment, the formation position of the pattern may be corrected on the pattern data.

[0228] In the modification of the fourth embodiment, in the first writing process (S194), the shot data generation unit 70 first corrects the formation position of the pattern on the writing data based on a first correction amount map having the correction amount (dx1stn, dy1stn) for the first writing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0229] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0230] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0231] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the first writing process. In the modification of the fourth embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx1stn, dy1stn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, the center position or the position of the center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) for example four pixels 36 at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0232] Similarly, in the second drawing process (S196), the shot data generation unit 70 first corrects the formation position of the pattern on the drawing data based on a second correction amount map having the correction amount (dx2ndn, dy2ndn) for the second drawing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0233] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0234] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0235] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the second writing process. In the modification of the fourth embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx2ndn, dy2ndn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, the center position or the position of the center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) for example four pixels 36 at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0236] As described above, according to the fourth embodiment, it is possible to correct positional deviations of beam irradiation positions and pattern formation positions in overlay writing caused by irreversible deformation of the sample 101 due to irradiation with the multibeams 20 (electron beams).

[0237] Embodiment 5. In the fifth embodiment, with regard to the overlay drawing described in the fourth embodiment, a case is described in which, when the first drawing process is performed without correction, the second drawing process is performed so as to maintain the relative position to the position drawn in the first drawing process. The configuration of the drawing device 100 in the fifth embodiment is similar to that in FIG. 24, except that the final positional deviation amount calculation unit 52, the correction amount calculation unit 56, and the correction amount map creation unit 58 are omitted.

[0238] FIG. 32 is a diagram showing an example of a state of misalignment on the substrate surface in the fifth embodiment. Figure 32 shows the state before the start of the first drawing process, the state when drawing at the desired position in the first drawing process, the state after the first drawing process is completed, the state when drawing at the desired position in the second drawing process, and the state after the second drawing process is completed.

[0239] In FIG. 32, the designed beam irradiation position in the first writing process is indicated by vector A11. The designed beam irradiation position in the second writing process is indicated by vector A21. If the position of vector A11 before the start of writing process is written as it is without correction in the first writing process on the target LTEM substrate, at the time of writing the position of vector A21 in the second writing process, the position of vector A11 before the start of writing process is physically moved to a position (vector A11+(vector B12-vector B11)) that is moved by the vector indicated by (vector B12-vector B11) from the position of vector A11 before the start of writing process due to deformation caused by contraction of the substrate as shown in FIG. 32. Similarly, the position of vector A21 before the start of writing process is physically moved to a position (vector A21+(vector B12-vector B11)) that is moved by the vector indicated by (vector B12-vector B11) from the position of vector A21 before the start of writing process due to deformation caused by contraction of the substrate as shown in FIG. 32.

[0240] In the fifth embodiment, the second drawing process is performed using a layout pattern different from that of the first drawing process, and therefore the second drawing process performs overlapping drawing while maintaining the beam irradiation position and the relative positional relationship in the first drawing process. Therefore, when drawing in the second drawing process, a position (vector A21+(vector B12-vector B11)) obtained by correcting the position of vector A21 before the start of the process by the vector indicated by (vector B12-vector B11) is drawn as the beam irradiation position (or pattern formation position). As a result, after the drawing process of the entire substrate after the second drawing process is completed, the beam irradiation position (or pattern formation position) drawn in the first drawing process and the beam irradiation position (or pattern formation position) drawn in the second drawing process are different from the positions of vectors A11 and A21 before the start of the process, but can have the same relative positional relationship.

[0241] A flowchart showing a part of an example of the main steps of the writing method in the fifth embodiment is similar to that in Fig. 27, except that the final positional deviation amount (vector C12) calculation step (S103), the correction amount calculation step (S123), the determination step (S124), and the first correction amount map creation step (S127) are omitted. A flowchart showing the rest of the example of the main steps of the writing method in the fifth embodiment is similar to that in Fig. 28. In the fifth embodiment, no correction is made in the first writing process, so the correction amount is not calculated in the first writing process.

[0242] The contents of the dose map creation process (S101), the drawing schedule creation process (S107), and the drawing position deviation amount (vector B11) calculation process (S121) in embodiment 5 are similar to the contents of the dose map creation process (S101), the drawing schedule creation process (S107), and the drawing position deviation amount (vector B11) calculation process (S121) in Figure 27 described in embodiment 4. In other words, in the drawing positional deviation amount (vector B11) calculation process (S121), the drawing positional deviation amount calculation unit 54 calculates the drawing positional deviation amount (first positional deviation amount) from the designed position of the first chip pattern caused by the irreversible deformation of the sample 101 due to the electron beam irradiated to the sample 101 prior to the irradiation time of the electron beam in the first drawing process for drawing the first chip pattern when the sample 101, which irreversibly deforms depending on the distribution of the electron beam dose, is irradiated with an electron beam to draw a pattern.

[0243] The contents of the drawing positional deviation amount (vector B12) calculation step (S131) ​​in the fifth embodiment are similar to the contents of the drawing positional deviation amount (vector B12) calculation step (S131) ​​in FIG. In other words, in the drawing positional deviation amount (vector B12) calculation process (S131), the drawing positional deviation amount calculation unit 62 calculates the drawing positional deviation amount (second positional deviation amount) from the designed position of the second chip pattern caused by the irreversible deformation of sample 101 due to the electron beam irradiated to sample 101 prior to the irradiation time of the electron beam in the second drawing process in which the second chip pattern is drawn so as to overlap the first chip pattern.

[0244] In the correction amount calculation step (S133), the correction amount calculation unit 64 calculates a correction amount (vector B12-vector B11) (another example of a first correction amount) for correcting a pattern formation position or a beam irradiation position when irradiating an electron beam in a second writing process corresponding to a target electron beam in the first writing process, based on the positional deviation amount (vector B11). Based on the difference between the positional deviation amount at writing in the second writing process (vector B12) and the positional deviation amount at writing in the first writing process (vector B11), a correction amount (vector B12-vector B11) (another example of a first correction amount) for correcting a pattern position or an electron beam irradiation position when irradiating an electron beam to a sample 101 to form a pattern in the second writing process is calculated. In other words, the correction amount (dx2ndn, dy2ndn) of each position within the global mesh region 11 that is irradiated (drawn) with the beam for the nth time can be calculated by subtracting the positional deviation amount at time of drawing (dx2ndwrite-n, dy2ndwrite-n) from the positional deviation amount at time of drawing (dx1stwrite-n, dy1stwrite-n).

[0245] The contents of the determination step (S134) and the second correction amount map creation step (S137) in embodiment 5 are similar to the contents of the determination step (S134) and the second correction amount map creation step (S137) in FIG. 27 described in embodiment 4.

[0246] The contents of the first mark measurement step (S180) and the first GMC correction step (S182) in the fifth embodiment are similar to those described in the first mark measurement step (S180) and the first GMC correction step (S182) in FIG. 28.

[0247] The drawing mechanism 150 in the fifth embodiment corrects the position of a pattern or the irradiation position of the electron beam when the sample 101 is irradiated with an electron beam to form a pattern in the second drawing process, based on the difference between the amount of positional deviation during drawing in the second drawing process and the amount of positional deviation during drawing in the first drawing process. The drawing mechanism 150 also performs a first drawing process of drawing a first chip pattern on the sample 101, and a second drawing process of drawing a second chip pattern on the sample 101 based on the above-mentioned correction amount. A specific description will be given below.

[0248] In the first writing step (S184), the shot data generation unit 70 uses the dose map for the first writing process to calculate the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0249] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0250] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) as a first writing process. In the fifth embodiment, in both the real-time mode and the pre-processing mode, under the control of the deflection control circuit 130, when writing, the deflector 208 deflects the beam array to a design position for a representative position (for example, a center position or a position of a center beam) of the beam array for each tracking cycle, and while each beam writes (exposes) for example, four pixels 36 at that position during the tracking cycle, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation region 34) does not shift in relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation region 34) follow the movement of the XY stage 105.

[0251] The contents of each step from the developing / etching / resist coating step (S186) to the second GMC correction step (S194) are the same as the contents of each step from the developing / etching / resist coating step (S186) to the second GMC correction step (S194) in FIG. 28 described in the fourth embodiment.

[0252] In the second writing step (S196), the shot data generation unit 70 calculates, for each pixel 36, an incident irradiation amount D(x) (dose amount) for irradiating the pixel 36 for the second writing process. In other words, the incident irradiation amount D(x) (dose amount) is calculated by multiplying the irradiation amount defined in the dose map by the reference irradiation amount Dbase. When the incident irradiation amount D(x) (dose amount) is defined in the dose map, it may be used as is.

[0253] Next, the shot data generation unit 70 calculates the irradiation time for the second drawing process for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0254] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in the shot order for the second drawing process, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the shot order.

[0255] Under the control of the drawing control unit 76, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-beam 20 (electron beam) based on the beam irradiation position corrected by the correction amount (dx2ndn, dy2ndn). The drawing mechanism 150 draws while moving the XY stage 105. Specifically, under the control of the deflection control circuit 130 (an example of a correction unit), the deflector 208 deflects the beam array (irradiation area) to a position corrected by the correction amount (dx2ndn, dy2ndn) of the global mesh area 11 including the representative position of the beam array (for example, the center position or the position of the central beam) for each tracking cycle of the multi-beam 20. The deflection position of the beam array (irradiation area 34) is set based on the representative position of the beam array described above (for example, the center position or the position of the central beam).

[0256] In the modification of the fifth embodiment, similarly to the modification of the fourth embodiment, the formation position of the pattern may be corrected on the pattern data.

[0257] The content of the first writing step (S194) in the modification of the fifth embodiment is similar to that of the first writing step (S194) in the fifth embodiment.

[0258] In the second drawing process (S196) in the modified example of the fifth embodiment, the shot data generation unit 70 first corrects the formation position of the pattern on the drawing data based on a correction amount map having the correction amount (dx2ndn, dy2ndn) for the second drawing process for each global mesh region (xn, yn) as an element value. Specifically, the operation is as follows. For each global mesh region 11, the shot data generation unit 70 corrects the position of the pattern included in the global mesh region 11 by the correction amount defined for the global mesh region 11.

[0259] Then, the shot data generating unit 70 creates a dose map for the first drawing process again using the corrected pattern layout. The method of creating the dose map is the same as that described above. Then, the shot data generating unit 70 calculates the irradiation time for each pixel 36. The irradiation time for each pixel 36 can be calculated by dividing the incident irradiation amount D(x) of the pixel by the current density J.

[0260] Then, the data processing unit 72 rearranges the obtained irradiation time data for each pixel 36 in shot order, and stores the data in the storage device 142. The transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in shot order.

[0261] Under the control of the writing control unit 76, the writing mechanism 150 writes a pattern on the sample 101 using the multibeams 20 (electron beams) based on the beam irradiation position corrected by the correction amount as the second writing process. In the modified example of the fifth embodiment, the position of the pattern on the pattern data has already been corrected by the correction amount (dx2ndn, dy2ndn) in both the real-time mode and the pre-processing mode. Therefore, when writing, under the control of the deflection control circuit 130, the deflector 208 deflects the beam array to a design position for a representative position (for example, a center position or a position of a center beam) of the beam array for each tracking cycle, and during the tracking cycle, while each beam writes (exposes) four pixels 36, for example, at that position, the deflector 208 deflects the entire multibeams 20 collectively so that the beam array (irradiation area 34) does not shift its relative position with respect to the sample 101 due to the movement of the XY stage 105, thereby making the beam array (irradiation area 34) follow the movement of the XY stage 105.

[0262] As described above, according to the fifth embodiment, even if the positional deviation of the beam irradiation position or the pattern formation position in the first drawing process in the overlay drawing is not corrected, the positional deviation of the beam irradiation position or the pattern formation position due to the irreversible deformation of the sample 101 caused by the irradiation of the multi-beam 20 (electron beam) in the second drawing process can be corrected.

[0263] Although the embodiments have been described above with reference to specific examples, the present invention is not limited to these specific examples. Furthermore, the functions of the processes described in each embodiment may be executed by a computer, and a program for causing a computer to execute such functions of the processes may be stored in a non-transitory, tangible, readable recording medium such as a magnetic disk device.

[0264] Although the description of the device configuration, control method, and other parts not directly necessary for the explanation of the present invention have been omitted, the required device configuration and control method can be appropriately selected and used. For example, the description of the control unit configuration that controls the drawing device 100 has been omitted, but it goes without saying that the required control unit configuration can be appropriately selected and used.

[0265] In addition, all electron beam writing methods, electron beam writing apparatuses, and programs that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. [Explanation of symbols]

[0266] 12 LTEM board 13Cr membrane 14 Alignment Mark 16 Resist film 20 Multibeam 22 holes 24 Control electrode 25 Passing hole 26 Counter electrode 29 Sub-irradiation area 30 drawing area 31 Blanking aperture array board 32 Stripe Area 33 Support substrate 34 Irradiation area 36 pixels 41 Control circuit 50 Dose Map Creation Department 52 Final position deviation calculation unit 54 Drawing position deviation calculation unit 56 Correction amount calculation section 58 Correction amount map creation section 62 Drawing position deviation amount calculation unit 64 Correction amount calculation section 66 Correction amount map creation section 67 Mark deviation amount calculation unit 68 GMC correction section 69 Mark position correction unit 70 Shot data generation unit 72 Data Processing Department 74 Transfer Processing Unit 76 Drawing control section 100 drawing device 101 Sample 102 Electron Tube 103 Drawing room 105 XY Stage 110 Control computer 112 Memory 130 Deflection control circuit 132,134 DAC amplifier unit 136 Lens control circuit 137 Detection Circuit 138 Stage Control Mechanism 139 Stage Position Measuring Instrument 140,142 Storage device 150 Drawing mechanism 160 Control Circuits 200 Electron Beam 201 Electron Gun 202 Lighting lens 203 Shaped aperture array substrate 204 Blanking Aperture Array Mechanism 205 Reduction Lens 206 Limiting Aperture Board 207 Objective Lens 208 Deflector 209 Deflector 210 Mirror 212 Detector 330 Membrane Region

Claims

1. a step of calculating a first positional deviation amount from a design position of a pattern caused by irreversible deformation of a sample after completion of a writing process when the pattern is written by irradiating the sample with an electron beam, the sample being irreversibly deformed depending on an irradiation dose distribution of the electron beam; calculating a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the sample with the electron beam based on the first positional deviation amount; performing a writing process of writing the pattern on the sample based on the correction amount; 1. An electron beam writing method comprising:

2. The method further includes a step of calculating a second positional deviation amount from a design position of the pattern caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample prior to the irradiation time of the electron beam, at a time point of the irradiation of the electron beam, in the writing process; 2. The electron beam writing method according to claim 1, wherein the correction is performed based on a difference between the second positional deviation amount and the first positional deviation amount.

3. the drawing process includes a first drawing process for drawing a first chip pattern, and a second drawing process, which is performed after the first drawing process, for drawing a second chip pattern so as to overlap the first chip pattern, 2. The electron beam writing method according to claim 1, wherein the first positional deviation amount is a positional deviation amount from a designed position of the pattern due to irreversible deformation of the workpiece after the second writing process is completed.

4. calculating a second positional deviation amount from the designed position at a time point of irradiation of the electron beam in the first writing process, the second positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated onto the sample prior to the time point of irradiation; calculating a third positional deviation amount from the designed position at a time point of irradiation of the electron beam in the second writing process, the third positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated onto the sample prior to the time point of irradiation; Further equipped with The step of calculating the correction amount includes: calculating a first correction amount in the first drawing process based on a difference between the second positional deviation amount and the first positional deviation amount; calculating a second correction amount in the second drawing process based on a difference between the third positional deviation amount and the first positional deviation amount; 4. The electron beam writing method according to claim 3, further comprising the steps of:

5. An alignment mark is formed in advance on the sample, The sample is placed on a movable stage; measuring a first mark position of the mark before the first writing process; calculating a positional deviation of a mark position from the first mark position due to an irreversible deformation of the sample after completion of the first writing process; measuring a second mark position of the mark before the start of the second writing process in a state in which the sample is once removed from the stage and is placed on the stage again for the second writing process; calculating a third mark position by correcting the second mark position by an amount of positional deviation of the mark position from the second mark position before starting the second writing process; Equipped with a position of the first chip pattern drawn on the sample during the first drawing process is defined based on a position of the first mark; a position of the second chip pattern drawn on the sample during the second drawing process is defined based on the third mark position; 4. The electron beam writing method according to claim 3.

6. a stage for mounting a sample that is deformed irreversibly depending on the distribution of the dose of the electron beam; a first positional deviation amount calculation unit that calculates a first positional deviation amount from a designed position of the pattern caused by irreversible deformation of the sample after completion of writing of the pattern on the sample using an electron beam; a correction amount calculation unit that calculates a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the sample is irradiated with the electron beam based on the first positional deviation amount; a writing mechanism that writes the pattern on the sample based on the correction amount; 1. An electron beam lithography apparatus comprising:

7. a function of calculating a first positional deviation amount from a design position of a pattern caused by irreversible deformation of a sample after completion of a writing process when the pattern is written by irradiating the sample with an electron beam, the sample being irreversibly deformed depending on a distribution of an irradiation amount of the electron beam; a function of storing the first positional deviation amount in a storage device; a function of reading out the first positional deviation amount from the storage device, and calculating, based on the first positional deviation amount, a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the sample with the electron beam; A program for causing a computer to execute the following.

8. a step of calculating a first positional deviation amount from a designed position of the first chip pattern at a time point of irradiation of the electron beam, the first positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample before the time point of irradiation of the electron beam, in a first writing process for writing a first chip pattern when a pattern is written by irradiating the electron beam to the sample which irreversibly deforms depending on an irradiation amount distribution of the electron beam; a step of calculating a second positional deviation amount from a designed position of the second chip pattern caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample before the irradiation time of the electron beam in a second writing process for writing a second chip pattern so as to overlap the first chip pattern; correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the sample with the electron beam in the second writing process based on a difference between the second positional deviation amount and the first positional deviation amount; performing the first writing process of writing the first chip pattern on the sample and the second writing process of writing the second chip pattern on the sample based on the correction amount; 1. An electron beam writing method comprising:

9. a stage for mounting a sample that is deformed irreversibly depending on the distribution of the dose of the electron beam; a positional deviation amount calculation unit that calculates a first positional deviation amount from a designed position of the first chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample before the irradiation time at the time of the electron beam irradiation in a first writing process for writing a first chip pattern when a pattern is written by irradiating the sample with the electron beam, and calculates a second positional deviation amount from a designed position of the second chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample before the irradiation time at the time of the electron beam irradiation in a second writing process for writing a second chip pattern so as to overlap the first chip pattern; a correction amount calculation unit that calculates a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the sample with the electron beam in the second writing process, based on a difference between the second positional deviation amount and the first positional deviation amount; a writing mechanism that performs the first writing process of writing the first chip pattern on the sample and the second writing process of writing the second chip pattern on the sample based on the correction amount; 1. An electron beam lithography apparatus comprising:

10. a function of calculating a first positional deviation amount from a design position of the first chip pattern at a time point of irradiation of the electron beam, the first positional deviation amount being caused by irreversible deformation of the sample caused by the electron beam irradiated to the sample prior to the time point of irradiation of the first chip pattern, in a first writing process for writing a first chip pattern when a pattern is written by irradiating the electron beam to the sample which irreversibly deforms depending on an irradiation amount distribution of the electron beam; a function of calculating, in a second writing process for writing a second chip pattern so as to overlap the first chip pattern, a second positional deviation amount from a designed position of the second chip pattern caused by irreversible deformation of the sample due to the electron beam irradiated to the sample before the irradiation time of the electron beam at the time of irradiation of the electron beam; a function of storing the first positional deviation amount and the second positional deviation amount in a storage device; a function of reading out the first positional deviation amount and the second positional deviation amount from the storage device, and calculating a correction amount for correcting a position of the pattern or an irradiation position of the electron beam when the pattern is formed by irradiating the sample with the electron beam in the second writing process, based on a difference between the second positional deviation amount and the first positional deviation amount; A program for causing a computer to execute the following.

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