JP2004294774A - Electron beam drawing method, method for manufacturing master pattern, master pattern, method for manufacturing mold, mold, optical device and electron beam drawing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam drawing method by which an image is drawn in a shorter time and the drawing feature can be uniformly maintained without being influenced by the scanning position of the electron beam in the drawing region. <P>SOLUTION: Frequency signals having controlled amplitudes according to the scanning position (position of a superposition quantity division field) of the electron beam in a specified drawing region (drawing field) are superposed on the input signal to a deflector which deflects the electron beam so as to oscillate an electron beam B in a sub scanning direction (Y direction in the figure) in the drawn plane (surface of a resist layer L) of a substrate 2. Thereby, the electron beam B is made to scan in the main scanning direction (X direction in the figure) while meandering, and the degree of meandering is controlled to a value according to the position of the superposition quantity division field in the field. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drawing technique using an electron beam, and more particularly to a technique for drawing a predetermined pattern, for example, a diffraction pattern corresponding to an optical element, on a substrate to be drawn by an electron beam.
[0002]
[Prior art]
In recent years, attempts have been made to perform drawing using an electron beam drawing apparatus (for example, see Patent Document 1). In such an electron beam writing apparatus, it is generally required to perform writing with a small beam diameter in order to form a fine pattern shape on a base material. On the other hand, when it is desired to finish drawing in a short time to increase production efficiency or to fine-tune the line width to be drawn, it is partially desired to perform drawing with a large beam diameter. is there.
[0003]
[Patent Document 1]
Japanese Patent Application No. 2002-333722
(Paragraphs [0061]-[0160], FIGS. 1 to 4)
[0004]
[Problems to be solved by the invention]
However, for example, in a general spot beam type electron beam writing apparatus, the beam diameter of the electron beam is usually set in a range of several nm to several tens nm, and the beam diameter is reduced in order to shorten the writing time. If the thickness is made larger than this, there is a problem that it becomes impractical due to problems such as aberration.
[0005]
On the other hand, in such an electron beam writing apparatus, even when writing is performed within the same depth of focus within one field, the electron beam slightly varies depending on the scanning position of the electron beam to be drawn. Is generated, a part drawn at the just focus position and a part drawn at the defocus position occur. Since there is a difference in the dose amount, there is a problem that the shape of the resist obtained after development is not uniform.
[0006]
In particular, when the resist layer, which is the layer to be drawn, is drawn so as not to reach the base material, a remarkable difference in the planarity appears on the surface of the resist layer after development.
[0007]
Therefore, in order to improve this, it is desirable to control the position of the substrate so that the drawing height is always constant in order to correct the aberration of the electron beam. If the robot has a three-dimensional structure, if such position control is performed by a mechanical operation using a stage or the like, accurate positioning is difficult, and the number of movements increases, resulting in an increase in productivity. A problem of extremely lowering occurs.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to perform drawing in a shorter time and to form a drawing shape without being influenced by a scanning position in a drawing area of an electron beam. It is an object of the present invention to provide an electron beam writing method capable of maintaining uniformity.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 irradiates an electron beam to a predetermined drawing area on a base material to be drawn, scans in a main scanning direction, and scans the main scanning direction. An electron beam writing method for writing a predetermined pattern by repeating scanning in the sub-scanning direction in the sub-scanning direction, wherein the obtaining step obtains shape data of the predetermined pattern, and based on the shape data of the predetermined pattern. A dividing step of dividing the drawing surface of the base material into the predetermined drawing region, and for each of the divided predetermined drawing regions, an emitted electron beam based on the shape data of the predetermined pattern, A signal generating step of generating a first input signal for deflecting in the main scanning direction and a second input signal for deflecting in the sub-scanning direction; A frequency adjustment step of adjusting a frequency signal having a specific frequency according to the scanning position of the beam; a superimposition step of superimposing the frequency signal on the second input signal; Scanning in the main scanning direction by deflecting in accordance with the first input signal, and scanning in the sub-scanning direction by deflecting in accordance with the second input signal on which the frequency signal is superimposed. It is characterized by the following.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of an electron beam writing method according to the present invention will be specifically described with reference to the drawings.
[0011]
[Configuration of base material]
First, the configuration of the base material drawn by the electron beam drawing apparatus will be described. In this example, a case where a blaze-shaped diffraction grating structure is formed while performing circular drawing on one surface of a base material having a curved surface will be described as an example, but the present invention is not limited thereto. Instead, for example, one surface of the substrate may be a flat surface or the like. Further, the diffraction grating structure may have a binary shape.
[0012]
FIG. 1 shows a drawing pattern formed on one surface of the substrate after the substrate is subjected to the development processing, and a shape of the detail thereof. As shown in FIG. 1, a circular drawing is performed on one surface of the base material 2 as an example of a drawing pattern. When a portion E which is a part of the drawing portion is enlarged, a diffraction grating structure including a plurality of blazes 3 is formed. Is formed. The blaze 3 forms an inclined portion 3b and a side wall 3a, and the inclined portion 3b is formed in a plurality of steps in a curved shape along the circumferential direction.
[0013]
More specifically, as shown in FIG. 2, the base material 2 has a curved surface portion 2a formed on at least one surface, and forms the diffraction grating at every pitch L1 by tilting the diffraction grating. In L1, a side wall 3a rising from the curved surface 2a at the break point of the pitch, a slope 3b formed between the adjacent side walls 3a, 3a, and a boundary region between the side wall 3a and the slope 3b. Is formed.
[0014]
The inclined portion 3b forms an inclined surface having one end in contact with the base end of one side wall 3a and the other end in contact with the tip of the other side wall 3a. Note that, as described later, the diffraction grating structure including the plurality of blazes 3 is formed by drawing a coating material (resist) applied on the curved surface portion 2a using an electron beam drawing apparatus and developing the coating material (resist). The inclined portion 3b, the side wall 3a, and the groove 3c of the blaze 3 form a uniform shape by drawing by an electron beam drawing device described later.
[0015]
[Configuration of Electron Beam Writing Apparatus]
Next, a specific configuration of an electron beam drawing apparatus used for drawing the above-described substrate 2 will be described.
[0016]
FIG. 3 is an explanatory diagram showing the overall configuration of the electron beam writing apparatus. As shown in FIG. 3, the electron beam lithography apparatus 1 forms a high-resolution, high-resolution electron beam probe and scans it at high speed on the substrate 2 to be drawn. An electron gun 12 which is an electron beam irradiation means for forming an electron beam probe and generating an electron beam to irradiate a target with a beam, a slit 14 for passing an electron beam from the electron gun 12, and a slit 14 An electron lens 16 for controlling a focal position of the passing electron beam with respect to the base material 2, an aperture 18 provided on a path from which the electron beam is emitted, and a substrate serving as a target by deflecting the electron beam. It comprises a deflector 20 for controlling the scanning position on the material 2 and the like, and a correction coil 22 for correcting deflection. These components are disposed in the lens barrel 10 and are kept in a vacuum state when emitting an electron beam.
[0017]
Note that the electron gun 12 corresponds to the “electron beam irradiation unit” of the present invention. The deflector 20 corresponds to the “electron beam scanning unit” of the present invention.
[0018]
Further, the electron beam writing apparatus 1 includes an XYZ stage 30 serving as a mounting table for mounting the substrate 2 to be written, and a transport for transporting the substrate 2 to a mounting position on the XYZ stage 30. A loader 40 as a means, a measuring device 80 as a measuring means for measuring a reference point on the surface of the substrate 2 on the XYZ stage 30, and a stage driving means 50 as a driving means for driving the XYZ stage 30 A loader driving device 60 for driving the loader; a vacuum exhaust device 70 for evacuating the inside of the lens barrel 10 and the housing 11 including the XYZ stage 30 to a vacuum; and control means for controlling these components And a control circuit 100.
[0019]
The electronic lens 16 generates a plurality of electronic lenses by supplying a current to each of the coils 17a, 17b, and 17c that are separately installed at a plurality of locations along the height direction, and generates the above-described current value. By controlling, the focal position and focal width (width of beam waist) of the electron beam are adjusted.
[0020]
The measuring device 80 includes a first laser length measuring device 82 that measures the base material 2 by irradiating the base material 2 with a laser, and a laser beam (first light measuring device) emitted by the first laser length measuring device 82. (A first irradiation light) reflects the base material 2 and receives the reflected light, and a second laser measuring device that performs irradiation from a different irradiation angle from the first laser measuring device 82. Device 86, and a second light receiving section 88 that reflects the laser light (second irradiation light) emitted from the second laser length measuring device 86 on the base material 2 and receives the reflected light. It is configured.
[0021]
The stage driving means 50 includes an X direction driving mechanism 52 for driving the XYZ stage 30 in the X direction, a Y direction driving mechanism 54 for driving the XYZ stage 30 in the Y direction, and a Z direction driving mechanism for driving the XYZ stage 30 in the Z direction. A mechanism 56 and a θ-direction drive mechanism 58 that drives the XYZ stage 30 in the θ direction are configured. In addition, an α-direction drive mechanism that can be driven to rotate in the α-direction about the Y-axis and a β-direction drive mechanism that can be driven to rotate in the β-direction about the X-axis are provided. You may comprise so that rolling is possible. This makes it possible to operate the XYZ stage 30 three-dimensionally and perform alignment.
[0022]
The control circuit 100 includes an electron gun power supply unit 102 for supplying power to the electron gun 12, an electron gun control unit 104 for adjusting and controlling current, voltage, and the like in the electron gun power supply unit 102, and an electron lens 16 (a plurality of And a lens control unit 108 for adjusting and controlling each current corresponding to each electronic lens in the lens power supply unit 106. Note that the electron gun power supply unit 102 has a D / A converter (not shown) for supplying power to the electron gun 12, and the electron gun control unit 104 operates in the D / A converter (not shown). By controlling the current, voltage, and the like, the dose of the electron beam emitted from the electron gun 12 is adjusted. Therefore, based on the minimum clock of the D / A converter, the dose amount of the minimum adjustment unit of the electron beam writing apparatus is determined.
[0023]
Further, the control circuit 100 includes a coil control unit 110 for controlling the correction coil 22, a shaping / deflecting unit 112 a for deflecting in the shaping direction by the deflector 20, and a deflection in the sub-scanning direction by the deflector 20. Sub-deflector 112b for performing the operation, a main deflector 112c for deflecting in the main scanning direction by the deflector 20, and a high-speed D / D converter for controlling the conversion of digital signals into analog signals for controlling the shaping deflecting unit 112a. A high-speed D / A converter 114b for converting and controlling a digital signal to an analog signal for controlling the A converter 114a, the sub deflection unit 112b, and a conversion control for converting a digital signal to an analog signal for controlling the main deflection unit 112c And a high-precision D / A converter 114c.
[0024]
Further, the control circuit 100 corrects a position error in the deflector 20, that is, supplies a position error correction signal and the like to each of the high-speed D / A converters 114a and 114b and the high-precision D / A converter 114c. A position error correction circuit 116 for prompting the position error correction by supplying the signal to the coil control unit 110 to correct the position error by the correction coil 22; An electric field control circuit 118, which is an electric field control means for controlling the electric field of the electron beam by controlling the D / A converters 114a and 114b and the high-precision D / A converter 114c, and a drawing pattern and the like are generated for the substrate 2. And a pattern generation circuit 120 for performing the operation. Incidentally, the pattern generation circuit 120 generates a predetermined drawing pattern based on information on various drawing pattern shapes stored in the memory 160 as described later.
[0025]
Further, the control circuit 100 includes a first laser drive control circuit 130 that controls the movement of the laser irradiation position and the drive control of the laser irradiation angle by moving the first laser length measuring device 82 up, down, left, and right; A second laser drive control circuit 132 for controlling the movement of the laser irradiation position by moving the second laser length measuring device 86 up, down, left and right and the laser irradiation angle, and the first laser length measuring device A first laser output control circuit 134 for adjusting and controlling the output (laser light intensity) of the laser irradiation light at 82 and an adjustment control for the output of the laser irradiation light at the second laser length measuring device 86 A second laser output control circuit 136, a first measurement calculation unit 140 for calculating a measurement result based on the light reception result of the first light reception unit 84, and a second light reception unit Based on the reception result at 8, and includes a second measurement calculating section 142 for calculating the measurement results.
[0026]
Further, the control circuit 100 includes a stage control circuit 150 for controlling the stage driving means 50, a loader control circuit 152 for controlling the loader driving device 60, and the first and second laser driving circuits 130, 132,. A mechanism control circuit 154 for controlling the first and second laser output control circuits 134 and 136, the first and second measurement calculation sections 140 and 142, the stage control circuit 150, the loader control circuit 152, and the vacuum exhaust device 70 A vacuum evacuation control circuit 156 for controlling vacuum evacuation, a measurement information input unit 158 for inputting measurement information, a memory 160 as storage means for storing the input information and other plural pieces of information, A program memory 162 that stores a control program for performing control, and a control formed by, for example, a CPU or the like that controls these units. Is constructed and a section 170.
[0027]
In the electron beam writing apparatus 1, in the so-called “operation system” or “operation means” including the measurement information input unit 158 and the like, selection of an analog scan method / digital scan method, a drawing pattern of a basic shape is performed. Various command operations such as selection from a plurality of commands are possible.
[0028]
The above-described sub-deflection unit 112b, high-speed D / A converter 114b, electric field control circuit 118, memory 160, program memory 162, and control unit 170 constitute "scanning pitch control means" of the present invention. Further, the above-described XYZ stage 30, stage driving means 50 and stage control circuit 150 constitute "position adjusting means" of the present invention.
[0029]
In the electron beam lithography apparatus 1 having the above-described configuration, when the substrate 2 transported by the loader 40 is placed on the XYZ stage 30, the air in the lens barrel 10 and the housing 11 is evacuated by the vacuum exhaust device 70. After exhausting dust and dust, the electron gun 12 emits an electron beam.
[0030]
The electron beam emitted from the electron gun 12 is deflected by the deflector 20 through the electron lens 16 and is deflected by the electron beam B (hereinafter, only the deflection-controlled electron beam after passing through the electron lens 16 is referred to as “ The electron beam B is sometimes referred to as “electron beam B”), and the drawing is performed by irradiating a drawing position on the surface of the substrate 2 on the XYZ stage 30, for example, a curved portion (curved surface) 2a.
[0031]
At this time, the measuring device 80 measures the drawing position (at least the height position among the drawing positions) on the base material 2 or the position of a reference point, which will be described later, and the control circuit 100 determines the position based on the measurement result. By adjusting and controlling each current value flowing through the coils 17a, 17b, 17c, etc. of the electronic lens 16, the position of the depth of focus of the electron beam B, that is, the focus position is controlled so that the focus position becomes the drawing position. Is controlled.
[0032]
Alternatively, based on the measurement result, the control circuit 100 controls the stage driving means 50 to move the XYZ stage 30 so that the focal position of the electron beam B becomes the drawing position.
[0033]
Further, in this example, the control may be performed by either one of the control of the electron beam and the control of the XYZ stage 30, or may be performed by using both.
[0034]
(measuring device)
Next, the measuring device 80 will be described with reference to FIG. More specifically, as shown in FIG. 4, the measuring device 80 includes a first laser length measuring device 82, a first light receiving unit 84, a second laser length measuring device 86, a second light receiving unit 88, and the like. Have.
[0035]
The first laser beam is emitted from the first laser length measuring device 82 to the substrate 2 in a direction intersecting the electron beam, and the first light beam S1 transmitted through the substrate 2 is received. Is detected.
[0036]
At this time, as shown in FIG. 4, the first light beam S1 is reflected by the flat portion 2b of the base material 2, and thus is reflected on the flat portion 2b of the base material 2 based on the first intensity distribution. The (height) position is measured and calculated. However, in this case, the (height) position on the curved surface portion 2a of the substrate 2 cannot be measured.
[0037]
Therefore, in this example, a second laser length measuring device 86 is further provided. That is, the second laser beam irradiates the substrate 2 with the second laser length measuring device 86 from the direction substantially orthogonal to the electron beam different from the first light beam S1 and transmits through the substrate 2. The second light intensity distribution is detected by receiving the second light beam S2 via the pinhole 84 included in the second light receiving unit 88.
[0038]
In this case, as shown in FIGS. 5A to 5C, the second light beam S2 passes through the curved surface portion 2a, so that the base material 2 is flattened based on the second intensity distribution. The (height) position on the curved surface portion 2a protruding from the portion 2b can be measured and calculated.
[0039]
Specifically, when the second light beam S2 passes through a specific height at a certain position (x, y) on the curved surface portion 2a in the XY reference coordinate system, at this position (x, y), FIG. As shown in (A) to (C), when the second light beam S2 hits the curved surface of the curved surface portion 2a, scattered light SS1 and SS2 are generated, and the light intensity of the scattered light is weakened. In this way, as shown in FIG. 6, the position is measured and calculated based on the second light intensity distribution detected by the second light receiving unit 88.
[0040]
In this calculation, as shown in FIG. 6, the signal output Op of the second light receiving unit 88 has a correlation between the signal output Op and the height of the base material as shown in the characteristic diagram of FIG. Therefore, by storing this characteristic, that is, a correlation table indicating the correlation in advance in the memory 160 or the like of the control circuit 100, the height position of the base material is determined based on the signal output Op from the second light receiving unit 88. Can be calculated.
[0041]
Then, using the height position of the base material as, for example, a drawing position, the focal position of the electron beam is adjusted, and drawing is performed.
[0042]
(Overview of the principle of drawing position calculation)
Next, an outline of the principle of calculating a writing position when writing is performed in the electron beam writing apparatus 1 will be described.
[0043]
First, as shown in FIGS. 8A and 8B, the substrate 2 is preferably formed by an optical element such as a resin, for example, an optical lens, and a flat portion 2b having a substantially flat cross section. And a curved surface portion 2a having a curved surface protrudingly formed from the flat portion 2b. The curved surface of the curved surface portion 2a is not limited to a spherical surface, and may be a free-form surface having a change in any other height direction such as an aspheric surface.
[0044]
In such a substrate 2, before the substrate 2 is previously placed on the XYZ stage 30, a plurality of, for example, three reference points P00, P01, and P02 on the substrate 2 are determined and their positions are measured. (First measurement). Thus, for example, the X axis is defined by the reference points P00 and P01, and the Y axis is defined by the reference points P00 and P02, and the first reference coordinate system in the three-dimensional coordinate system is calculated. Here, the height position in the first reference coordinate system is set to Ho (x, y) (first height position). Thereby, the thickness distribution of the substrate 2 can be calculated.
[0045]
On the other hand, the same processing is performed after the substrate 2 is placed on the XYZ stage 30. That is, as shown in FIG. 8A, a plurality of, for example, three reference points P10, P11, P12 on the base material 2 are determined and their positions are measured (second measurement). Thus, for example, the X axis is defined by the reference points P10 and P11, and the Y axis is defined by the reference points P10 and P12, and the second reference coordinate system in the three-dimensional coordinate system is calculated.
[0046]
Further, a coordinate conversion matrix or the like for converting the first reference coordinate system to the second reference coordinate system is calculated based on these reference points P00, P01, P02, P10, P11, and P12, and this coordinate conversion matrix is calculated. The height position Hp (x, y) (second height position) corresponding to the Ho (x, y) in the second reference coordinate system is calculated using this position, and this position is calculated as the optimum focus position, That is, the drawing position is a position where the focal position of the electron beam should be adjusted. Thereby, the above-described correction of the thickness distribution of the base material 2 can be performed.
[0047]
Note that the above-described second measurement can be performed using the measuring device 80 as the first measuring means of the electron beam writing apparatus 1.
[0048]
Then, the first measurement needs to be performed in advance at another place using another measurement device. As such a measuring device for measuring a reference point in advance before placing the base material 2 on the XYZ stage 30, a measuring device (second measuring means) having the same configuration as the measuring device 80 described above is used. ) Can be adopted.
[0049]
In this case, the measurement result from the measuring device, that is, the thickness distribution information of the base material 2 is input to the measurement information input unit 158 shown in FIG. The data is transferred through the memory 160 and stored in the memory 160. Of course, there may be cases where this measuring device is not required.
[0050]
As described above, the drawing position is calculated, and the focus position of the electron beam is controlled to perform the drawing.
[0051]
Specifically, as shown in FIG. 8C, the focal position of the focal depth FZ of the electron beam (beam waist BW = the narrowest point of the beam diameter) is set to one field of the unit space (three-dimensional reference coordinate system). Adjustment control is performed to the drawing position within (m = 1) (this control is performed by one or both of the adjustment of the current value by the electron lens 16 and the drive control of the XYZ stage 30 as described above). At this time, the focal position of the focal depth FZ of the electron beam (beam waist BW = the narrowest part of the beam diameter) is adjusted to the central part of one field by drive control of the XYZ stage 30. In this example, the fields are set such that the height of one field is longer than the depth of focus FZ, but the present invention is not limited to this. Here, as shown in FIG. 9, the depth of focus FZ indicates the height of the effective range of the beam waist BW of the electron beam B emitted through the electron lens 16. Incidentally, as described above, the width of the beam waist BW is adjusted by controlling each current value flowing through the coils 17a, 17b, 17c and the like of the electronic lens 16. In the case of the electron beam B, as shown in FIG. 9, when the width D of the electron lens 16 and the depth f from the electron lens 16 to the beam waist BW are D / f, about 0.01, for example, It has a resolution of about 50 nm and a depth of focus of, for example, about several tens of microns.
[0052]
Then, as shown in FIG. 8 (C), for example, by sequentially scanning in the X direction while shifting in the Y direction in one field, drawing in one field is performed. Further, if there is an area in which no image is drawn in one field, the area is moved in the Z direction while controlling the above-described focal position, and the same scanning process is performed.
[0053]
Next, after the drawing in one field is performed, in the other fields, for example, the field of m = 2 and the field of m = 3, the drawing processing is performed in real time while measuring and calculating the drawing position as described above. Will be performed. In this manner, when all the drawing is completed for the drawing area to be drawn, the drawing process on the surface of the base material 2 ends.
[0054]
In this example, this drawing area is a drawing layer, and a portion corresponding to the curved surface of the curved surface portion 2a in the drawing layer is a drawing surface.
[0055]
Further, a processing program for performing processing such as the various arithmetic processing, measurement processing, and control processing as described above is stored in the program memory 162 as a control program in advance.
[0056]
(Control system)
Next, a control system in the electron beam writing apparatus 1 will be described with reference to FIG.
[0057]
As shown in FIG. 10, the base material 2 input in advance in the above-described measurement information input unit 158 or transferred in advance through a network (not shown) connected to the control circuit 100 is stored in the memory 160. Is stored as other information 161d. Further, the shape storage table 161 is drawn on, for example, a curved surface portion 2a of the base material 2 set based on the thickness distribution information of the base material 2. Dose distribution information 161a in which a dose distribution corresponding to each scanning position of the side wall portion 3a and the inclined portion 3b of the blaze 3 is defined, and a beam corresponding to each scanning position of the side wall portion 3a and the inclined portion 3b of the blaze 3 as well. Beam diameter information 161b with a predefined diameter, field division corresponding to each drawing position when drawing the side wall 3a and the inclined portion 3b of the blaze 3, and Predefined fields sorting information 161c to the size of the segment of the superposition amount divided fields are stored. Incidentally, the size of the field division is set based on the deflection range (scanning range) of the electron beam B deflected by the deflector 20 by the input signal from the sub-deflection unit 112b. In addition, the size of the section of the superposition amount division field is set based on the size of the section of this field. Further, the memory 160 stores a superimposition amount correction table 164 for correcting the amplitude of a frequency signal superimposed on a deflection signal of the electron beam B described later.
[0058]
On the other hand, the program memory 162 stores a processing program 163a for the control unit 170 to perform processing described later, and other processing programs 163c.
[0059]
Incidentally, the setting means 181 shown in FIG. 10 stores the dose distribution information 161a, the beam diameter information 161b, the field division information 161c included in the shape storage table 161 of the memory 160, the superimposition amount correction table 164 stored in the memory 160, and the like. It is for setting. The display unit 182 is for displaying, for example, dose distribution information for each scanning line.
[0060]
In such a configuration, the control unit 170 controls the blaze 3 based on the dose distribution information 161a and the beam diameter information 161b stored in the shape storage table 161 of the memory 160 according to the processing program 163a stored in the program memory 162. A dose amount corresponding to each scanning position of the side wall portion 3a and the inclined portion 3b is calculated, and this is made to correspond to each of the fields divided based on the field division information 161c. Further, under the control of the control unit 170, the pattern generation circuit 120 generates a drawing pattern corresponding to each of the divided fields. Thereby, the shape data of the drawing pattern is obtained.
[0061]
Further, the control unit 170 calculates a probe current, a scanning pitch, and a diameter of the electron beam B corresponding to each scanning position of the side wall 3a and the inclined portion 3b of the blaze 3 from the above-described dose. Then, based on the calculated probe current, scanning pitch, and diameter of the electron beam B, control of the electron gun control unit 104, the electric field control circuit 118, the lens control unit 108, and the like is performed. As a result, the probe current, the scanning pitch, and the diameter of the electron beam B at the time of drawing are optimized. Note that the diameter of the electron beam B can also be adjusted by changing the size of the opening of the aperture 18.
[0062]
Further, the control unit 170 controls the stage control circuit 150 by the mechanism control circuit 154, and the stage control circuit 150 controls the driving of the stage driving unit 50, so that a predetermined field is located immediately below the emission position of the electron beam B. The XYZ stage 30 is moved so that the central part of the inside is located. Thus, the optimized electron beam B is applied to a predetermined drawing position in a predetermined field.
[0063]
(Frequency superposition circuit)
Next, the sub-deflection unit 112b, which is a characteristic part of the present invention, and more specifically, the frequency superposition circuit forming the sub-deflection unit 112b will be described with reference to FIG.
[0064]
As shown in FIG. 11, based on an input from the high-speed D / A converter 114b, the sub-deflection unit 112b determines a deflection signal in the X direction defined in advance in the apparatus, more specifically, “+” in the X direction. Input / output circuits 113a and 113b for outputting deflection signals having phases of "" and "-" to the respective deflecting plates 21a and 21b opposed to the deflector 20, and deflection signals in the Y direction orthogonal to the X direction. Are input / output circuits 113c and 113d for outputting deflection signals having phases of “+” and “−” in the Y direction to the respective deflecting plates 21c and 21d opposed to the deflector 20, and input / output circuits 113a and 113d. For signals input to any phase side (in this example, the input / output circuits 113b and 113d on the “−” phase side) among the input / output circuits 113b and 113c and 113d, Frequency superposing circuit 115 for superposing the frequency signal (e.g., radio frequency signal) having a frequency of constant, is configured to include a. Incidentally, the input / output circuits 113b and 113d add the deflection signal of the electron beam B input from the high-speed D / A converter 114b and passed through the input / output circuits 113a and 113c and the frequency signal from the frequency superposition circuit 115. By doing so, these are superimposed and their polarities are inverted. Further, these input / output circuits 113b and 113d can be constituted by ordinary arithmetic circuits.
[0065]
The high-frequency superimposing circuit 115 and the input / output circuits 113b and 113d constitute "frequency superimposing means" of the present invention.
[0066]
As described above, the control unit 170 controls the electron gun control unit 104, the electric field control circuit 118, the lens control unit 108, and the like to control the probe current, the scanning pitch, and the diameter of the electron beam B when performing drawing. After the adjustment, the stage control circuit 150 is controlled by the mechanism control circuit 154, and the stage control circuit 150 controls the driving of the stage driving means 50. The XYZ stage 30 is moved so that the electron beam emission position of the electron gun 12 is positioned at the center of the predetermined field.
[0067]
When the electron beam is irradiated from the electron gun 12 after such preparation, the electron beam is deflected by the deflector 20 via the electron lens 16, and the deflected electron beam B is transmitted to the XYZ stage. Irradiation is performed on a surface of the substrate 2 to be drawn on the surface 30, that is, a predetermined position in a predetermined field on the curved surface portion 2a. At this time, the electron beam B is deflected by the above-described deflector 20, and is sequentially scanned in the main scanning direction while shifting the field in the sub-scanning direction, for example (for each predetermined field, the electron beam in the main scanning direction). Is repeated in the sub-scanning direction), thereby drawing a predetermined pattern.
[0068]
Here, for example, when a blazed diffractive structure is formed on the curved surface portion 2a of the base material 2, the sub-deflecting portion 112b having the above-described configuration is controlled by the control portion 170 within one field. Electron beam drawing is performed as described below.
[0069]
In the following, it is assumed that the "X direction defined in advance in the apparatus" and the "Y direction orthogonal to the X direction" correspond to the main scanning direction and the sub-scanning direction of the electron beam B, respectively. Accordingly, the deflection signal in the X direction corresponds to the “first input signal” of the present invention. Further, the deflection signal in the Y direction corresponds to the “second input signal” of the present invention.
[0070]
As described above, after moving the XYZ stage 30 so that the emission position of the electron beam of the electron gun 12 is located at the center in the predetermined field, the XYZ stage 30 is moved to the predetermined position in the predetermined field on the curved surface 2a of the base material 2. When the electron beam B is irradiated with the electron beam B, the electron beam B slightly generates an aberration, and is irradiated in a shape as shown in FIG.
[0071]
As shown in FIG. 12, the shape of the electron beam B is substantially a perfect circle in the drawing area located immediately below the emission position of the electron beam and located at the center of the field. However, as the distance from the drawing area increases, the aberration of the electron beam B increases. As a result, the shape of the electron beam B becomes large and elliptical.
[0072]
As described above, the variation in the shape of the electron beam B due to the position of the drawing area in one field is such that the curved surface portion 2a of the base material 2 has a portion to be drawn at the just focus position and a defocus position. This results in a non-uniform resist shape after development between the part drawn at the just-focused position and the part drawn at the defocused position. Need arises.
[0073]
Therefore, in the electron beam drawing apparatus 1, as shown in FIG. 13A (or FIG. 13B), the electron beam B is swung in the sub-scanning direction (Y direction in the figure) to Is scanned in the main scanning direction (X direction in the figure) while meandering, and at the same time, the degree of the meandering is adjusted according to the position of the drawing area in the field, so that the side wall 3a of the blaze 3 obtained after development and It is assumed that drawing is performed to make the shape of the inclined portion 3b (or the binary shape 4) uniform.
[0074]
Specifically, as shown in FIG. 14, the deflection signal in the Y direction, which is the sub-scanning direction of the electron beam B, is input to the input / output circuit 113d by the frequency superposition circuit 115 of the sub-deflection unit 112b. As shown in FIG. 13A (or FIG. 13B), by superimposing a frequency signal on the deflection signal in the Y direction, the electron beam B is applied to the resist layer L, which is the layer to be drawn, as shown in FIG. By scanning in the Y direction in the figure, the electron beam scans in the X direction while meandering.
[0075]
However, the amplitude of the above-described frequency signal is controlled in accordance with the position of a drawing area (hereinafter, referred to as a superimposition amount division field) in the field, and the frequency signal is controlled as shown in FIG. As shown in FIG. 13B), the amplitude of the scanning line trajectory of the electron beam B is maximized in the overlap amount division field located at the center of the field, and becomes smaller as the distance from the overlap amount division field increases. It is adjusted to. Thereby, the shape of the side wall portion 3a and the inclined portion 3b (or the binary shape 4) of the blaze 3 obtained after the development can be made uniform. The details of the adjustment of the amplitude of the frequency signal will be described later.
[0076]
In this example, since the X direction matches the main scanning direction of the electron beam B, the deflection signal in the X direction, more specifically, the deflection signal in the X direction input to the input / output circuit 113b is used. On the other hand, it is not necessary to superimpose the frequency signal.
[0077]
By the way, in the electron beam writing apparatus 1, when writing the side wall 3 a and the inclined portion 3 b (or the binary shape 4) of the blaze 3 on the curved surface 2 a of the base material 2, compared with the conventional case, Can be reduced. This is because, as is clear from FIGS. 15A and 15B, when the electron beam B is scanned in the X direction while meandering the electron beam by swinging the electron beam B in the Y direction in FIG. BW width D ₂ Is the width D of the conventional beam waist BW ₁ This is because even if the value is the same as that of, a larger range can be drawn.
[0078]
That is, in the electron beam drawing apparatus 1, when drawing the inclined portion 3b (or the binary shape 4) of the blaze 3, the electron beam B is swung in the sub-scanning direction (Y direction) to meander the electron beam. By performing scanning in the main scanning direction (X direction) while performing the scanning, it is possible to obtain the same effect as if the electron beam was scanned with a beam diameter larger than before. Further, by appropriately adjusting such an effect according to the position of the drawing area in one field, that is, by oscillating the electron beam B in the Y direction according to the position of the drawing area in one field, By adjusting the degree of meandering of the electron beam, the variation in the shape of the electron beam B due to the position of the drawing area in one field described above is corrected, and as a result, the side wall of the blaze 3 obtained after development The shapes of the 3a and the inclined portion 3b (or the binary shape 4) can be made uniform.
[0079]
By the way, even when the electron beam B is swung in the Y direction, the electron beam B scans in the X direction while meandering the electron beam, the speed of scanning the electron beam B in the X direction is the same as in the conventional case. It is. This is because the deflection signal in the X direction, which is the main scanning direction of the electron beam B, more specifically, the deflection signal in the X direction input to the input / output circuits 113a and 113b is not different from the conventional one.
[0080]
Therefore, in the electron beam drawing apparatus 1, the electron beam B is swung in the sub-scanning direction, thereby scanning while making the electron beam meander, thereby reducing the number of times the electron beam B is scanned when drawing. And drawing can be completed in a shorter time. Further, even when the number of scans is equal to that in the conventional case, the effect of obtaining a smoother shape can be obtained.
[0081]
However, in such a case, since the dose per unit area of the resist L, which is the layer to be drawn, decreases, the electron gun control unit 104 controls the electron gun power supply unit 102 under the control of the control unit 170. By controlling the voltage and the like, the irradiation amount of the electron beam B irradiated from the electron gun 12 is adjusted (increased), and the dose amount is made equal to the conventional case.
[0082]
Further, in the electron beam drawing apparatus 1, the scanning pitch (drawing) of the adjacent electron beam B is determined in accordance with the amplitude of the frequency signal superimposed on the deflection signal in the Y direction which is the sub-scanning direction of the electron beam B. (Interval) is controlled. The details of the adjustment of the scanning pitch will be described later.
[0083]
Returning to FIG. 11, the frequency superimposing circuit 115 adjusts the amplitude of the frequency signal superimposed on the signal input to the input / output circuits 113b and 113d according to the gain external control signal from the control unit 170. 117b, and a variable frequency circuit 119 that adjusts the frequency of a frequency signal to be superimposed on signals input to the input / output circuits 113b and 113d. Incidentally, the variable gain circuits 117a and 117b can be configured by a variable resistance attenuator or the like. Further, the variable frequency circuit 119 can be constituted by a VCO (Valtage Control Oscillator) or the like.
[0084]
Note that the variable gain circuits 117a and 117b and the control section 170 constitute "amplitude adjusting means" of the present invention.
[0085]
Thus, in the electron beam drawing apparatus 1, as shown in FIGS. 13A and 13B, the electron beam B is swung in the Y direction in the drawing on the resist layer L which is the layer to be drawn. The amplitude related to the trajectory of the scanning line when scanning in the X direction while meandering the beam can be adjusted.
[0086]
That is, for example, according to the position of the overlap amount division field in the field, the frequency related to the trajectory of the scanning line of the electron beam B becomes the maximum in the overlap amount division field located at the center in the field by the variable gain circuit 117b. The deflection signal in the Y direction, which is the sub-scanning direction of the electron beam B, and more specifically, the deflection signal in the Y direction input to the input / output circuit 113d so as to become smaller as the distance from the superimposition amount division field increases. By adjusting the amplitude of the frequency signal to be superimposed, as shown in FIGS. 13A and 13B, the electron beam B is swung in the Y direction in the drawing on the resist layer L which is the layer to be drawn. It is possible to adjust the amplitude related to the trajectory of the scanning line when scanning in the X direction while meandering the electron beam.
[0087]
The deflection signal in the Y direction, which is the sub-scanning direction of the electron beam B, more specifically, the frequency signal superimposed on the deflection signal in the Y direction input to the input / output circuit 113d is a so-called high-frequency signal. Since the electron beam B is close to the response frequency band (cut-off frequency) of the deflector 20, the electron beam B is swung in the Y direction in FIG. It is also possible to adjust the frequency related to the trajectory of the scanning line when scanning in the X direction while meandering B.
[0088]
As described above, the amplitudes of the frequency signals superimposed on the signals input to the input / output circuits 113b and 113d are adjusted by the variable gain circuits 117a and 117b according to a gain external control signal from the control unit 170.
[0089]
At this time, the control unit 170 obtains information on the size and position of the overlapping amount division field in the field from the field division information 161c of the shape storage table 161 stored in the memory 160, and stores the information in the program memory 162. By performing the arithmetic processing according to the processing program 163a, the position of the central part of the field and the position of each superimposition amount division field in the field are determined, and the amplitude of the frequency signal corresponding to the position of each superimposition amount division field is determined. The calculated information is transmitted to the variable gain circuits 117a and 117b as the above gain external control signal.
[0090]
By the way, the control unit 170 performs control for adjusting the scanning pitch (drawing interval) of the adjacent electron beam B in addition to the control for adjusting the amplitude of the scanning line of the electron beam B by the variable gain circuit 117b described above. . Specifically, the control unit 170 determines the scanning interval of the electron beam from the width of the beam waist BW, the amplitude of the scanning line of the electron beam B, and the frequency of the scanning line of the electron beam B. In consideration of the influence of the proximity effect (drawing influence range), the value is determined so that the drawing influence ranges do not overlap each other and there is no part leaking from the drawing influence range. Incidentally, the influence of the proximity effect determined from the width of the beam waist BW and the amplitude and frequency of the trajectory of the scanning line of the electron beam B, that is, the information on the drawing influence range is previously stored in the memory 160 as other information 161d. Is stored.
[0091]
At this time, the control unit 170 performs the processing stored in the program memory 162 based on the information on the amplitude and the frequency of the frequency signal described above and the information on the drawing influence range stored as other information 161d in the memory 160. By performing arithmetic processing according to the program, the drawing interval between adjacent electron beams B is calculated, and further, by controlling the electric field control circuit 118, control is performed to adjust the scanning pitch of the electron beam B to the drawing interval. .
[092]
(Drawing process)
Here, the flow of the drawing process by the control unit 170 of the electron beam drawing apparatus 1 will be described with reference to the flowcharts shown in FIGS. In this example, a case is described in which a blaze-shaped diffraction structure is drawn on the curved surface portion 2a of the base material 2.
[0093]
As shown in FIG. 16, the control unit 170 first sets the beam diameter of the electron beam B to be irradiated to each superimposition amount division field in the field as advance preparation for drawing (S01). Note that the beam diameter of the electron beam B is defined by the positional relationship between the electron beam emission position of the electron gun 12 and each of the overlapping amount division fields in the field. Incidentally, the beam diameter of the electron beam B may be determined from the developed shape of the resist layer, which is the layer to be drawn on the substrate on which the line drawing or the spot drawing has been performed, for example.
[0094]
Next, the control unit 170 creates a superposition amount correction table based on the result of setting the beam diameter of the electron beam B (S02). Specifically, the superposition amount correction table referred to here is superimposed on a deflection signal for deflecting the electron beam B when the electron beam B is scanned in each superposition amount division field in the field. This is for defining a correction value for correcting the amplitude of the frequency signal, and deflects the electron beam B when scanning the electron beam B in each of the overlap amount division fields in the field and the overlap amount division field. Is a table in which a correction value for a reference amplitude of a frequency signal to be superimposed on a deflection signal is associated with the deflection signal. Incidentally, the reference amplitude of the frequency signal is the frequency to be superimposed on the deflection signal for deflecting the electron beam B when scanning the electron beam B in the superposition amount division field located at the center in the field. It is the amplitude of the signal.
[0095]
Next, the controller 170 stores the superimposition amount correction table 164 in the memory 160 (S03).
[0096]
After such preliminary preparations are performed, the control unit 170 performs a process of drawing the side wall portion 3a and the inclined portion 3b of the blaze 3 on the curved surface portion 2a of the base material 2.
[0097]
<Acquisition step>
As shown in FIG. 17, first, the control unit 170 according to the processing program 163 a stored in the program memory 162 based on the dose distribution information 161 a and the beam diameter information 161 b stored in the shape storage table 161 of the memory 160. A dose amount corresponding to each scanning position of the side wall portion 3a and the inclined portion 3b of the blaze 3 is calculated. Further, under the control of the control unit 170, the pattern generation circuit 120 generates a diffraction structure of the blaze 3 to be drawn on the curved surface portion 2a of the base material 2, for example, a drawing pattern relating to the blaze orbicular zone (S04). Thereby, the shape data of the drawing pattern is obtained.
[0098]
<Segmentation step>
Further, the control unit 170 associates these with each of the fields divided based on the field division information 161c. Thereby, a drawing pattern of the blaze 3 corresponding to each field is created (S05).
[0099]
<Scanning pitch adjustment step>, <Signal generation step>
At this time, the control unit 170 performs calculation processing in accordance with the processing program stored in the program memory 162, thereby calculating drawing data relating to the blaze 3, specifically, a dose amount corresponding to the shape of the blaze 3, Further, based on the dose, settings are made regarding the probe current, the scanning pitch, the diameter of the electron beam B, and the deflection amount of the electron beam B for each field. That is, at this time, the scanning pitch is adjusted according to the amplitude of the frequency signal (S06), and a deflection signal for deflecting the electron beam B (the above-described deflection signal in the X direction and the Y direction) is generated. (S07).
[0100]
<Position adjustment step>
Next, the control unit 170 controls the driving of the stage driving unit 50 by controlling the stage control circuit 150, and moves the XYZ stage 30 to a desired position. That is, the XYZ stage 30 is moved so that the center of the first field is located immediately below the electron beam emission position of the electron gun 12 (S08).
[0101]
<Frequency adjustment step>
Next, the control unit 170 calculates the scanning position in the first field, that is, the position of the first overlapping amount division field (S09). Further, by referring to the superimposition amount correction table 164 stored in the memory 160, a correction value of the superimposition amount corresponding to the first superimposition amount division field is determined, and a deflection signal for deflecting the electron beam B is determined. It is determined whether there is a change in the amount of superimposition of the frequency signal to be superimposed on (S10). Here, when it is necessary to change (S10, Yes), the superposition amount of the frequency signal, that is, the amplitude is changed based on the superposition amount correction table 164 (S11).
[0102]
<Scanning step>
Next, the control unit 170 controls the electron gun control unit 104, the electric field control circuit 118, the lens control unit 108, and the like based on the above-described probe current, scanning pitch, and diameter of the electron beam B, so that the probe current Then, the drawing is started by optimizing the scanning pitch and the diameter of the electron beam B (S12).
[0103]
Next, the control unit 170 determines whether or not the drawing of all the regions has been completed in all the overlapping amount division fields in the first field (S13). Here, if there is an area where the drawing is not completed (S13, No), the XYZ stage 30 is moved to a desired height while controlling the focal position in the area, and the same operation is performed. A drawing process by scanning is performed (S09 to S12).
[0104]
Thereafter, the steps from S09 to S13 are repeated until all the writing in the first field is completed.
[0105]
When all drawing in the first field is completed (S13, Yes), the control unit 170 determines whether all drawing in all fields is completed (S14). Naturally, since all the drawing in all the fields has not been completed (S14, No), the process is shifted to the drawing in the next field (S15). Specifically, the control unit 170 controls the driving of the stage driving unit 50 by controlling the stage control circuit 150, and moves the XYZ stage 30 to a desired position. That is, the XYZ stage 30 is moved so that the center of the second field is located immediately below the electron beam emission position of the electron gun 12.
[0106]
Thereafter, the steps from S09 to S15 are repeated until all drawing in all fields is completed.
[0107]
In this manner, when all the drawing in all the fields is completed (S14, Yes), the process of drawing the side wall 3a and the inclined portion 3b of the blaze 3 on the curved surface 2a of the base material 2 ends.
[0108]
[Mold manufacturing method]
In the above description, the step of performing precision processing such as diffracted photons on a substrate by the electron beam lithography apparatus according to the present invention has been disclosed. A process for manufacturing a mold for manufacturing an optical lens such as described above by molding will be described with reference to FIG.
[0109]
First, a mold (electroless nickel or the like) is processed by machining (processing step). Next, as shown in FIG. 18A, a substrate 200A having a mother optical surface having a predetermined curved surface is resin-molded by a mold (resin molding step). Further, after the substrate 200 is washed, drying is performed.
[0110]
<Formation step>
Next, the surface treatment of the base material 200 is performed (resin surface treatment step). In this step, for example, a step such as Au deposition is performed. Specifically, as shown in FIG. 18B, the substrate 200 is positioned, and the spinner is rotated while dropping the resist L to perform spin coating. In addition, pre-paking is also performed. Thereby, the base material 200B having the resist film formed on the mother optical surface is obtained.
[0111]
After the spin coating, the thickness of the resist film is measured to evaluate the resist film (resist film evaluation step). Further, as shown in FIG. 18C, while controlling the base 200B in the X, Y, and Z axes, the base 200B is positioned, and a predetermined structure to be formed on the base 200B ( Here, drawing (exposure) by the electron beam B is performed on the resist film according to the diffraction grating structure).
[0112]
<Development step>
Next, the surface of the resist film L on the base material 200B is smoothed (surface smoothing step). Further, as shown in FIG. 18D, a developing process is performed while positioning the base material 200B and the like (developing step). At this time, the drawing influence range due to the drawing of the electron beam B, that is, the exposed portion is removed, and a predetermined structural pattern 202 is formed on the mother optical surface of the base 200B. Further, a surface hardening treatment is performed.
[0113]
Next, a step of evaluating the resist shape by SEM observation, a film thickness measuring device, or the like is performed (resist shape evaluation step).
[0114]
<Etching step>
Here, when etching is necessary to obtain a predetermined shape, that is, when a predetermined shape is obtained by further etching the resist shape obtained in the developing step, an etching process is performed by dry etching or the like. . In this way, a master mold serving as a master of a mold having a predetermined structure is obtained.
[0115]
<Electroforming step>
Then, a metal is vapor-deposited on the resist surface of the mother die 200C, and a pretreatment for electroforming of the die is performed (metal vapor deposition step). Next, as shown in FIG. 18E, an electroforming process or the like is performed on the surface-treated mother die 200C to form an electroformed member 203 on which a predetermined structure on the mother die 200C is transferred. .
[0116]
Next, as shown in FIG. 18 (F), a process of separating the mother die 200C and the electroformed member 203 is performed, and the die 204 is obtained by processing the outer shape.
[0117]
The surface treatment is performed on the mold 200C subjected to the surface treatment and the mold 204 peeled off (mold surface treatment step). Then, the mold 204 is evaluated.
[0118]
As described above, a mold for injection-molding an optical element described below can be easily manufactured.
[0119]
[Production method of optical element]
In the above, the process of manufacturing a mold for manufacturing an optical lens such as an optical element by molding has been described. In the following, however, the steps of the entire process including the above-described steps, that is, the optical lens Will be described with reference to FIG.
[0120]
As shown in FIG. 19A, resin molding for obtaining a molded product 300 is performed using the mold 204 after the above-described evaluation (resin molding step). Next, as shown in FIG. 19B, the molded article 300 is washed and then dried. Further, the molded article 300 is evaluated. Here, if the evaluation is good, the molded article 300 is an optical element as a product.
[0121]
As described above, the optical element can be easily manufactured.
[0122]
【The invention's effect】
As described above, according to the electron beam writing method according to the present invention, writing is performed in a shorter time, and the writing shape is kept uniform without being affected by the scanning position in the electron beam writing area. be able to.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for describing a schematic configuration in an embodiment of a base material that is a prototype of an optical element.
FIG. 2 is an explanatory diagram for describing details of a main part of a base material illustrated in FIG. 1;
FIG. 3 is an explanatory diagram for describing an overall configuration in an embodiment of an electron beam writing apparatus.
FIG. 4 is an explanatory diagram for describing a measurement principle in the measurement device of the electron beam writing apparatus shown in FIG.
FIGS. 5A to 5C are explanatory diagrams for explaining a method of measuring the surface height of a base material.
FIG. 6 is an explanatory diagram for describing a relationship between light projection and light reception of the measurement device of the electron beam writing apparatus shown in FIG.
FIG. 7 is a characteristic diagram showing a relationship between a signal output from a light receiving unit of the measuring device and a height of a base material.
8 (A) and 8 (B) are explanatory views showing a substrate to be drawn by the electron beam drawing apparatus shown in FIG. 1, and FIG. 8 (C) is for explaining the drawing principle; FIG.
FIG. 9 is an explanatory diagram for describing a beam waist of an electron beam.
FIG. 10 is a functional block diagram showing details of a control system of the electron beam writing apparatus shown in FIG.
11 is an explanatory diagram for describing a configuration of a peripheral portion including a sub-deflection unit of the electron beam writing apparatus shown in FIG.
FIG. 12 is an explanatory diagram for explaining that when irradiating each drawing area in a field with an electron beam, the diameter of the electron beam varies due to aberration of the electron beam.
FIG. 13 is an explanatory diagram for describing an example of an electron beam drawing method performed in the electron beam drawing apparatus shown in FIG. 1;
14 is an explanatory diagram for describing a process in which a frequency signal is superimposed on a deflection signal by a frequency superimposing circuit in a sub-deflection unit of the electron beam drawing apparatus shown in FIG.
FIG. 15A is an explanatory diagram for explaining a drawing range in a conventional electron beam scanning, and FIG. 15B is a diagram showing an electron beam performed by the electron beam drawing apparatus shown in FIG. FIG. 9 is an explanatory diagram for describing a drawing range in the scan of FIG.
16 is a flowchart illustrating a flow of a writing process in a control unit when writing is performed by the electron beam writing apparatus illustrated in FIG. 1;
17 is a flowchart illustrating a flow of a writing process in a control unit when writing is performed by the electron beam writing apparatus illustrated in FIG. 1;
FIGS. 18A to 18F are explanatory views for explaining an overall processing procedure when a molding die is formed using a base material.
FIGS. 19A and 19B are explanatory diagrams for explaining the overall processing procedure when an optical element is molded using a mold.
[Explanation of symbols]
1. Electron beam writing system
2 Base material
2a curved surface
3 Blaze
3a Side wall
3b Inclined part
3c groove
4 Binary shape
12 electron gun
16 Electronic lens
18 Aperture
20 Deflector
21a-21d deflection plate
30 XYZ stage
50 Stage drive means
100 control circuit
112b Sub deflection unit
113a-113d I / O circuit
115 Frequency superposition circuit
116 Position error correction circuit
117a, 117b Variable gain circuit
118 Electric field control circuit
119 Variable frequency circuit
120 pattern generator
150 Stage control circuit
154 Mechanism control circuit
160 memory
161 Shape memory table
161a Dose distribution information
161b Beam diameter information
161c Field classification information
161d Other information
162 program memory
163a Processing program
163c Other processing programs
164 Superposition amount correction table
170 control unit
181 Setting means
182 display means
B electron beam
BW Beam West
L resist layer

Claims (16)

The substrate to be drawn is irradiated with an electron beam for each predetermined drawing area, and is scanned in the main scanning direction, and the scanning in the main scanning direction is repeated in the sub-scanning direction, thereby forming a predetermined pattern. An electron beam drawing method for drawing,
An acquiring step of acquiring shape data of the predetermined pattern;
Based on the shape data of the predetermined pattern, a dividing step of dividing a drawing surface of the base material into the predetermined drawing area,
A first input signal for deflecting the emitted electron beam in the main scanning direction and a sub-scanning direction based on the shape data of the predetermined pattern for each of the divided predetermined drawing areas; A signal generating step of generating a second input signal for:
Frequency adjustment step of adjusting a frequency signal having a specific frequency according to the scanning position of the electron beam in the predetermined drawing area,
Superimposing the frequency signal on the second input signal;
Scanning in the main scanning direction by deflecting the emitted electron beam in accordance with the first input signal, and scanning in the sub-scanning direction by deflecting in accordance with the second input signal on which the frequency signal is superimposed. An electron beam writing method. 2. The electron beam writing method according to claim 1, wherein the amplitude of the frequency signal is adjusted according to a scanning position of the electron beam in the predetermined writing area. A position adjusting step of adjusting the center of the predetermined drawing area to a position immediately below the emission position of the electron beam, wherein the amplitude decreases as the distance from the center of the predetermined drawing area increases. 3. The electron beam writing method according to claim 2, wherein the adjustment is performed. 4. The apparatus according to claim 1, further comprising: a scanning pitch adjusting step of adjusting a scanning pitch of the electron beam in a sub-scanning direction according to an amplitude of the frequency signal. 5. Electron beam drawing method. 5. The electron beam writing method according to claim 1, wherein the predetermined pattern is a diffractive structure having a blazed shape. The electron beam drawing method according to any one of claims 1 to 5, wherein the drawing surface of the base material has a curved surface shape. A method of manufacturing a mold for manufacturing an optical element using a substrate drawn by the electron beam drawing method according to any one of claims 1 to 6. So,
Before drawing the base material, a forming step of forming a resist film on the base material,
Developing a resist film on the drawn base material to obtain a matrix having a predetermined structure. The method according to claim 7, further comprising an etching step of etching the base material developed in the developing step. A mother die manufactured by the method of manufacturing a mother die according to claim 7. A method for manufacturing a mold, comprising: performing an electroforming process using the matrix of claim 9 to obtain a mold on which the predetermined structure on the matrix has been transferred. A mold manufactured by the method for manufacturing a mold according to claim 10. An optical element formed by the mold according to claim 11. In order to draw a predetermined pattern on the substrate to be drawn,
Electron beam irradiation means for irradiating the base material with an electron beam for each predetermined drawing area,
The electron beam emitted from the electron beam irradiation means is scanned in the main scanning direction by deflecting the electron beam in accordance with a first input signal, and is scanned in the main scanning direction by deflecting in accordance with a second input signal. Electron beam scanning means repeating in the direction,
Frequency superimposing means for superimposing a frequency signal having a specific frequency adjusted in accordance with the scanning position of the electron beam in the predetermined drawing area on the second input signal. Electron beam writing apparatus. 14. The electron beam writing apparatus according to claim 13, wherein said frequency superimposing means has an amplitude adjusting means for adjusting an amplitude of said frequency signal in accordance with a scanning position of said electron beam in said predetermined drawing area. . Position adjusting means for adjusting the center of the predetermined drawing area immediately below the emission position of the electron beam, the amplitude adjusting means sets the amplitude of the frequency signal at the center of the predetermined drawing area. 15. The electron beam writing apparatus according to claim 14, wherein the distance is adjusted so as to be smaller as the distance from the unit increases. 14. The apparatus according to claim 13, further comprising scanning pitch control means for controlling a scanning pitch of the electron beam in a sub-scanning direction by controlling the electron beam scanning means according to the amplitude of the frequency signal. The electron beam writing apparatus according to claim 15.

Images