JP2006053311A - Electron beam drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam drawing method for improving the quality of electron beam drawing. <P>SOLUTION: The position of a starting point of electron beams parallel to each other is swung in a predetermined scanning direction, so that, for example, when an irregular distance is produced in a fifth count, the position where an irregular distance is caused is unevenly shifted in the predetermined scanning direction and this improves the quality of electron beam drawing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electron beam drawing method, and more particularly to an electron beam drawing method suitable for manufacturing a mother die for molding an optical element having a fine structure and an optical element molding die.

  For example, in the field of optical pickup devices that have been rapidly developed in recent years, optical elements such as extremely high-precision objective lenses are used. Molding can be said to be suitable for mass production because a uniform shaped product can be rapidly produced when such an optical element is molded using a mold made of plastic or glass. In general, such dies are often manufactured by cutting one by one using, for example, a single crystal diamond tool. However, since the mold is a consumable part that wears out in accordance with the number of uses, it is necessary to replace the mold periodically. Therefore, it is necessary to prepare a mold of the same shape in preparation for replacement, but when a mold is manufactured by cutting with a single crystal diamond tool or the like, it can be said that it is difficult to cut out a mold of the same shape, Therefore, there is a possibility that the shape of the optical element product may vary before and after the mold replacement, and there is a problem that the cost is high.

  On the other hand, there is an attempt to create a die by growing, for example, electroforming on a mother die having a mother optical surface corresponding to the optical surface of the optical element. According to such an attempt, even if the pattern formed on the mother optical surface of the mother die is fine, it can be transferred and formed with high accuracy.

  By the way, the master pattern used for such a purpose is obtained by applying a resist to the mother optical surface of the substrate to be drawn, forming a fine pattern by, for example, electron beam drawing, developing the resist, and then performing dry etching. Can do. After such a mother die is attached to a jig with an adhesive or the like, an electroformed member that becomes a die can be formed by growing electroforming so as to cover the mother optical surface of the mother die.

Here, electron beam drawing will be described. A conventional example of such electron beam drawing is disclosed in Patent Document 1.
JP 2004-107793 A

  Since electron beam drawing forms a fine pattern, a beam running region (called a field) by a fine movement mechanism is extremely small, for example, 0.5 mm × 0.5 mm. On the other hand, an optical element such as an objective lens of the optical pickup device has a diameter of about 3 mm, and the mother optical surface of the drawing base is also sized accordingly. A fine pattern cannot be formed on the optical surface at once. Therefore, after drawing within one field of the electron beam, the electron beam irradiation source and the substrate to be drawn are moved relative to each other so that the next field can be drawn with the electron beam, and then the electron beam is drawn within the next field. A sequential drawing method has been devised. This is called a step-and-repeat method.

  Here, the inventors of the present invention are essentially smooth surfaces in the mother optical surface of the substrate to be drawn obtained by performing electron beam drawing by the step-and-repeat method and further developing. I found that a clear line appeared. Such a line is observed as a continuous convex part or concave part. The reason why such a line appears will be described.

  FIG. 1 is a schematic view showing scanning of an electron beam when performing electron beam writing by a step-and-repeat method according to the prior art. In FIG. 1, the scanning of the electron beam in one drawing field is indicated by an arrow, and the drawing made by the scanning of the electron beam is indicated by a line segment. The electron beam emitted from the electron gun can be arbitrarily deflected by adjusting the electric field through which the electron beam passes. Such deflection can be realized by using two means: a high-precision deflection unit having a position DAC (D / A converter) and a high-speed deflection unit having a scan DAC (D / A converter). First, the electric field is adjusted by the high-precision deflector so that the electron beam start point S1 in the first scan is irradiated with the electron beam. Further, the high-speed deflecting unit deflects the electron beam by a predetermined scanning distance a / n in a predetermined scanning direction every count, and repeats this for n counts (n is an integer of 2 or more) as the counter counts up. Then, the electron beam is scanned from the start point S1 to the end point E1 (see FIG. 1A).

  Subsequently, the starting point S2 of the electron beam in the next scanning is set to a point moved by a predetermined amount b in a direction orthogonal to the predetermined scanning direction, and the electron beam is deflected by the high-precision deflecting unit. Further, the electron beam is deflected by the predetermined scanning distance a / n in the predetermined scanning direction every count by the high-speed deflecting unit, and the electron beam is scanned from the start point S2 to the end point E2 by repeating this for n counts. (See FIG. 1 (b)).

  The starting point S3 of the electron beam in the next scanning is set as a point moved by a predetermined amount b in a direction orthogonal to the predetermined scanning direction, and is deflected by the high-precision deflecting unit so that the electron beam is irradiated here. Further, the electron beam is deflected by the predetermined scanning distance a / n in the predetermined scanning direction every count by the high-speed deflecting unit, and the electron beam is scanned from the start point S3 to the end point E3 by repeating this for n counts. (See FIG. 1 (c)). In this way, desired drawing can be formed by performing electron beam scanning over the entire area on the surface. Here, the reason why the high-precision deflection unit is used for positioning the start point S1 is that, for example, since the processing of the position information uses a 16-bit signal, the resolution is higher. On the other hand, the reason why the high-speed deflection unit is used for scanning the electron beam is that the processing speed is increased and the scanning can be performed more efficiently because the position information is processed using a 12-bit signal.

  However, in the processing of the high-speed deflection unit, a differential linearity error occurs when converting a digital value into an analog value, and scanning with an incorrect distance longer or shorter than the distance a / n may occur. Such an incorrect distance is slightly longer or shorter than the predetermined distance a / n, and does not impair the entire drawing of the electron beam. However, the irregular distance occurs every predetermined count (for example, 5 counts). Therefore, if the electron beam scanning is performed while moving in parallel, the parts scanned at an incorrect distance are arranged in a line and may be clearly recognized as one line, resulting in a quality problem.

  The present invention has been made in view of the problems of the prior art, and an object thereof is to provide an electron beam drawing method capable of improving the quality in electron beam drawing.

An electron beam drawing method according to a first aspect of the present invention is an electron beam drawing method in which drawing is performed by scanning an electron beam.
A first step of positioning a first starting point of the electron beam;
A second step of scanning in a predetermined scanning direction while irradiating the electron beam from the first start point;
A position where a second start point for starting another electron beam scan is shifted from the first start point by a first predetermined amount in the predetermined scanning direction and in a direction orthogonal to the predetermined scanning direction; And a third step
A fourth step of scanning in the predetermined scanning direction while irradiating the electron beam from the second starting point;
Further, a third starting point for starting scanning of another electron beam is shifted from the second starting point in the predetermined scanning direction by a second predetermined amount different from the first predetermined amount, and in the predetermined scanning direction. A fifth step with a position shifted in a direction orthogonal to
And a sixth step of scanning in the predetermined scanning direction while irradiating the electron beam from the third starting point.

  FIG. 2 is a schematic view showing scanning of an electron beam when performing electron beam drawing according to an example of the first present invention. In FIG. 2, the scanning of the electron beam in one drawing field is indicated by an arrow, and the drawing made by the scanning of the electron beam is indicated by a line segment. The electron beam emitted from the electron gun can be arbitrarily deflected by adjusting the electric field through which the electron beam passes. Such deflection can be realized by using two means: a high-precision deflection unit having a position DAC (D / A converter) and a high-speed deflection unit having a scan DAC (D / A converter). First, the electric field is adjusted by the high-precision deflector so that the electron beam start point S1 in the first scan is irradiated with the electron beam (first step). Further, the high-speed deflecting unit deflects the electron beam by a predetermined scanning distance a / n in a predetermined scanning direction every count, and repeats this for n counts (n is an integer of 2 or more) as the counter counts up. Then, the electron beam is scanned from the start point S1 to the end point E1 (second step; see FIG. 2A). So far, it is the same as the prior art.

  Subsequently, the starting point S2 of the electron beam in the next scanning is shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction, and the first predetermined amount −c (a negative sign is the scanning direction) in the predetermined scanning direction. The point is shifted only by the reverse direction (which means the opposite direction), and the high-precision deflection unit deflects the electron beam so that it is irradiated (third step). Further, the electron beam is deflected by the predetermined scanning distance a / n in the predetermined scanning direction every count by the high-speed deflecting unit, and the electron beam is scanned from the start point S2 to the end point E2 by repeating this for n counts. (Fourth step; see FIG. 2B).

  Further, the electron beam starting point S3 in the next scanning is a point shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction and shifted by a second predetermined amount d (≠ −c) in the predetermined scanning direction. The high-precision deflection unit deflects the electron beam so that it is irradiated here (fifth step). Further, the electron beam is scanned from the start point S3 to the end point E3 by deflecting the predetermined scanning distance a / n in the predetermined scanning direction every count by the high-speed deflecting unit and repeating this for a plurality of counts (sixth point). Step; see FIG. 2 (c)). In this way, desired drawing can be formed by performing electron beam scanning over the entire area on the surface.

  As described above, by shifting the positions of the start points of the parallel electron beams in the predetermined scanning direction, for example, even when an incorrect distance is generated at the fifth count, the position where the incorrect distance is generated is unevenly shifted in the predetermined scanning direction. Thus, the quality of electron beam drawing can be improved. In this sense, it is preferable that one of the first predetermined distance and the second predetermined distance is not a multiple of the other.

An electron beam drawing method according to a second aspect of the present invention is an electron beam drawing method in which drawing is performed by scanning an electron beam.
Every time the counter counts up one by one from the first starting point where the position in the predetermined scanning direction is determined by the count value (k + 0) when k is an arbitrary integer and n is an integer of 2 or more, A first step of moving the electron beam to a position corresponding thereto in the predetermined scanning direction and scanning the electron beam to a first end point determined by a count value (k + n);
A second step of determining a position of a second start point for starting scanning of another electron beam in a direction perpendicular to the predetermined scanning direction to be different from a position of the first start point;
When m is an arbitrary integer different from k, each time the counter sequentially counts up one by one from the second starting point where the position in the predetermined scanning direction is determined by the count value (m + 0) A third step of moving the electron beam to a predetermined position in a predetermined scanning direction and scanning the electron beam to a second end point determined by a count value (m + n).

  FIG. 3 is a schematic view showing scanning of an electron beam when performing electron beam drawing according to an example of the second aspect of the present invention. In FIG. 3, the scanning of the electron beam in one drawing field is indicated by an arrow, and the drawing made by the scanning of the electron beam is indicated by a line segment. The electron beam emitted from the electron gun can be arbitrarily deflected by adjusting the electric field through which the electron beam passes. Such deflection can be realized by using two means: a high-precision deflection unit having a position DAC (D / A converter) and a high-speed deflection unit having a scan DAC (D / A converter). First, the electric field is adjusted by the high-precision deflector so that the electron beam start point S1 in the first scan is irradiated with the electron beam (first step). The integer k of the present invention is 0 here. Further, the high-speed deflecting unit deflects the distance a / n in the predetermined scanning direction every count, and repeats this for n counts (n is an integer of 2 or more) in accordance with the counter count up, thereby starting from the starting point S1. The electron beam is scanned to the end point E1 (first step; see FIG. 3A). So far, it is the same as the prior art.

  Subsequently, the reference point P for electron beam scanning in the next scanning is set to a position shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction and shifted by a distance −e in the predetermined scanning direction. Then, a position shifted from the reference point P by a distance m · a / n (where m ≠ k = 0) is set as an electron beam scanning start point S2, and is deflected by the high-precision deflecting unit so that the electron beam is irradiated here. To do. Further, the stage is moved by the predetermined scanning distance a / n in the predetermined scanning direction every count from the count value m + 1 to m + n by the high-speed deflection unit, and this is repeated for n counts to repeat from the start point S2 to the end point E2. The electron beam is scanned (second step; see FIG. 3B).

  In addition, the reference point P of the electron beam scanning in the next scanning is shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction, and is shifted by a distance −e ′ (where e ≠ e ′) in the predetermined scanning direction. Position. Then, a position shifted from the reference point P by a distance m ′ · a / n (where m ≠ m ′) is set as an electron beam scanning start point S3, and is deflected by the high-precision deflector so that the electron beam is irradiated here. To do. Further, the high-speed deflection unit deflects the count value m ′ + 1 to m ′ + n by the predetermined scan distance a / n in the predetermined scan direction every count, and repeats this for n counts, thereby repeating from the start point S3 to the end point. The electron beam is scanned up to E3 (see FIG. 3C). In this way, desired drawing can be formed by performing electron beam scanning over the entire area on the surface.

  As described above, when the position of the start point of the parallel electron beam is shifted in the predetermined scanning direction, and the shift amount is canceled by the distance corresponding to the count value, for example, when an incorrect distance occurs at the fifth count. However, the position where the incorrect distance is generated is shifted in the predetermined scanning direction, and the quality of electron beam drawing can be improved.

  In particular, in this example, by setting m · a / n−e = 0 and m ′ · a / n−e ′ = 0, the start point and the end point of the parallel electron beams can be aligned. According to the first aspect of the present invention described above, the position where the incorrect distance is generated shifts unevenly in the predetermined scanning direction, but the start point and the end point of the electron beam scanning are also shifted unevenly. Therefore, it is necessary to similarly shift the end point or start point of the electron beam scanning. According to the second aspect of the present invention, such a problem can be solved.

  Accordingly, it is preferable that the position in the predetermined scanning direction at the second start point is shifted from the position in the predetermined scanning direction at the first start point by an amount determined by a count value (km).

An electron beam drawing method according to a third aspect of the present invention is an electron beam drawing method in which drawing is performed by scanning an electron beam.
A first step of positioning a first starting point of the electron beam;
A second step of scanning in a predetermined scanning direction from the first start point to the first end point while irradiating the electron beam;
A third step in which a second start point for starting another electron beam scan is shifted from the first end point in a direction crossing the predetermined scanning direction;
And a fourth step of scanning in the direction opposite to the predetermined scanning direction while irradiating the electron beam from the second starting point.

  FIG. 4 is a schematic view showing scanning of an electron beam when performing electron beam drawing according to an example of the third aspect of the present invention. In FIG. 4, the scanning of the electron beam in one drawing field is indicated by an arrow, and the drawing made by the scanning of the electron beam is indicated by a line segment. The electron beam emitted from the electron gun can be arbitrarily deflected by adjusting the electric field through which the electron beam passes. Such deflection can be realized by using two means: a high-precision deflection unit having a position DAC (D / A converter) and a high-speed deflection unit having a scan DAC (D / A converter). First, the electric field is adjusted by the high-precision deflector so that the electron beam start point S1 in the first scan is irradiated with the electron beam (first step). Further, the high-speed deflecting unit deflects the electron beam by a predetermined scanning distance a / n in a predetermined scanning direction every count, and repeats this for n counts (n is an integer of 2 or more) as the counter counts up. Then, the electron beam is scanned from the start point S1 to the end point E1 (second step; see FIG. 4A). So far, it is the same as the prior art.

  Subsequently, the second start point S2 for starting the scanning of the electron beam in the next scanning is set to a position shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction (it may also be shifted in the predetermined scanning direction). The high-precision deflection unit deflects the electron beam so that it is irradiated here (third step). Further, the electron beam is scanned from the start point S2 to the end point E2 by deflecting the predetermined scanning distance a / n in the direction opposite to the predetermined scanning direction every count by the high-speed deflection unit and repeating this for n counts. (Fourth step; see FIG. 4B).

  Further, the third start point S3 for starting the scanning of the electron beam in the next scanning is set to a position shifted by a predetermined amount b in a direction orthogonal to the predetermined scanning direction (may also be shifted in the predetermined scanning direction) The high-precision deflection unit deflects the electron beam so that it is irradiated there. Further, the high-speed deflection unit deflects the predetermined scanning distance a / n in the predetermined scanning direction (opposite to the second electron beam scanning) every count, and repeats this for n counts to start from the starting point S3. The electron beam is scanned up to the end point E3 (see FIG. 4C). In this way, desired drawing can be formed by performing electron beam scanning over the entire area on the surface.

  As described above, when the position of the end point of the electron beam is shifted in the predetermined scanning direction to be the starting point of another electron beam and then scanned in the reverse direction, for example, when an incorrect distance occurs at the fifth count. However, there is a low possibility that the positions at which the illegal distances are overlapped, so that the quality of electron beam drawing can be improved.

  It is preferable that the resolution of the D / A converter used for positioning the starting point of the electron beam is higher than the resolution of the D / A converter used for scanning the electron beam.

  ADVANTAGE OF THE INVENTION According to this invention, the electron beam drawing method which can aim at the quality improvement in electron beam drawing can be provided.

  Hereinafter, an example of a preferred embodiment of the present invention will be specifically described with reference to the drawings. First, a drawing substrate to be drawn by an electron beam will be described with reference to FIGS. FIG. 5 discloses a drawing pattern drawn on the substrate and a drawing shape of the details thereof.

  As shown in the figure, as an example of a drawing pattern drawn on a drawing base material (hereinafter referred to as a base material) 2 of the present embodiment, a diffraction ring zone by circular drawing is disclosed. When the portion A which is a part of the drawing portion is enlarged, a diffraction zone composed of a plurality of blazes 3 is formed on the base material 2 as shown in FIG.

  The blaze 3 has a shape in which an inclined portion (slope) 3b and a side wall portion 3a are repeatedly connected. More specifically, as shown in FIG. 7, the base material 2 has a curved surface portion 2a (base optical surface of the base material) formed on at least one surface, and is formed for each pitch L1 by tilting the diffraction grating. , At least one pitch L1 of the diffraction grating, a side wall portion 3a rising from the curved surface portion 2a at the pitch break, a slope portion 3b formed between the adjacent side wall portions 3a and 3a ′, and a side wall A groove 3c formed in a boundary region between the portion 3a and the inclined portion 3b ′ is formed. In addition, it is preferable that this diffraction ring zone is formed by drawing the coating agent (resist) apply | coated on the curved-surface part 2a so that it may mention later.

  Here, a polymer resin material that is cured by heating or ultraviolet rays is used for the resist, and the bond between molecules is broken and decomposed in accordance with the amount of energy given by the electron beam ( The decomposed portion is removed by a developer described later).

  In the step-and-repeat method of the present invention, the area drawn on the substrate shown in FIG. 5 is divided into a plurality of fields (drawing areas), and drawing with a beam is performed sequentially for each field, and the beam and the base. The step of relative movement of the material is repeated, and a predetermined pattern (here, a diffraction zone) is drawn on the substrate.

  Specifically, each field is arranged concentrically according to the drawn diffraction zone, and each field has a fan shape. The fields arranged concentrically in this way are arranged continuously from the center of the concentric circle of the diffraction zone in the radial direction of the concentric circle. In this way, the drawing area on the substrate is divided into a plurality of drawing areas. The number of fields arranged in the radial direction varies depending on the size of the substrate to be drawn and the scannable distance of the beam.

  In this embodiment, among these fields divided into a plurality of fields, the relationship between the field adjacent to the radial direction and the pattern is determined in advance. Can be done.

  Moreover, it is preferable that the base material 2 is a matrix material for forming an optical element used in the optical pickup device, for example, a mold for forming an objective lens. Since a plurality of dies having the same shape are created from the mother die obtained by the above drawing, it is possible to prevent variation in the shape of the optical element product at the time of die replacement. In such an optical element, a diffraction ring zone is provided for aberration correction in an optical pickup device that achieves DVD / CD compatibility using information recording light of different wavelengths. Hereinafter, a specific configuration of an electron beam drawing apparatus which is a premise for forming such a base material will be described.

(Overall configuration of electron beam lithography system)
Next, the overall schematic configuration of the electron beam drawing apparatus will be described with reference to FIGS. FIG. 8 is an explanatory diagram showing the overall configuration of the electron beam lithography apparatus of this example. FIG. 9 is a block diagram showing the position control calculation unit 300.

  As shown in FIG. 8, the electron beam drawing apparatus 1 of the present embodiment forms a high-resolution electron beam probe with a large current and scans the substrate 2 to be drawn at a high speed. An electron gun 12 as means, a slit 14 through which an electron beam from the electron gun 12 passes, an electron lens 16 for controlling the focal position of the electron beam passing through the slit 14 with respect to the substrate 2, and an electron beam An aperture 18 disposed on the path from which the light is emitted, a deflector 20 that controls a scanning position on the base material 2 that is a target by deflecting an electron beam, and a correction coil 22 that corrects the deflection. The high-resolution electron beam probe made of an electron beam is formed, and the target is irradiated with the beam by scanning the electron beam probe. These parts are arranged in the lens barrel 10 and maintained in a vacuum state when the electron beam is emitted.

  Further, the electron beam drawing apparatus 1 includes an XYZ stage 30 that is a placement table for placing the base material 2 to be drawn, and a transport for transporting the base material 2 to a placement 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 of the surface of the base material 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 exhausting the interior of the lens barrel 10 and the housing 11 including the XYZ stage 30 so as to be evacuated, and control means for controlling these And a control circuit 100.

  The electronic lens 16 is controlled by generating a plurality of electronic lenses according to the current values of the coils 17a, 17b, and 17c, which are spaced apart at a plurality of locations along the height direction. The focal position of the electron beam is controlled.

  The measuring device 80 is based on a laser oscillator 82 that measures the position in the height direction of the substrate 2 by irradiating the substrate 2 with a laser, and a laser beam (irradiated light) emitted by the laser oscillator 82. The light receiving portion 84 receives the reflected light when reflected by the material 2. The laser oscillator 82 includes a collimator lens.

  The stage drive means 50 includes an X direction drive mechanism 52 that drives the XYZ stage 30 in the X direction, a Y direction drive mechanism 54 that drives the XYZ stage 30 in the Y direction, and a Z direction drive that drives the XYZ stage 30 in the Z direction. The mechanism 56 includes a θ-direction drive mechanism 58 that drives the XYZ stage 30 in the θ direction. As a result, the XYZ stage 30 can be operated three-dimensionally and alignment can be performed. That is, if the base material 2 is placed on the XYZ stage 30, the relative position with the electron gun 12 as a beam irradiation source can be arbitrarily changed, so that drawing can be performed by the above-described step-and-repeat method.

  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 and voltage in the electron gun power supply unit 102, and an electron lens 16 (multiple A lens power supply unit 106 for operating each of the electronic lenses, and a lens control unit 108 for adjusting and controlling currents corresponding to the electronic lenses in the lens power supply unit 106. The

  Further, the control circuit 100 includes a high-speed deflection unit 112a for deflecting the electron beam by the deflector 20 to scan the substrate, and a position of a region in which the high-speed deflection unit 112a scans the electron beam by the deflector 20. And a high-precision deflecting unit 112b for designating.

  The control circuit 100 calculates a position error in the deflector 20 and prompts the high-speed deflection unit 112a and the high-precision deflection unit 112b to correct the position error, and the high-speed deflection unit 112a and the high-precision deflection. An electric field control circuit 118 that controls the electric field of the electron beam by controlling the unit 112b, and a pattern generation circuit 120 for generating a drawing pattern or the like on the substrate 2 are configured. The pattern generation circuit 120 generates a predetermined drawing pattern based on information regarding the shapes of various drawing patterns stored in the memory 160. The detailed configuration of the position control calculation unit 300 will be described later. By providing the position control calculation unit 300, for example, a line including a diagonal line can be drawn with high accuracy and high speed.

  Furthermore, the control circuit 100 adjusts and controls the output of laser irradiation light (laser light intensity) from the laser oscillator 82 and the measurement result based on the light reception result from the light receiving unit 84. And a measurement calculation unit 140 for calculation.

  Furthermore, 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, a laser output control circuit 134, a measurement calculation unit 140, and a stage control circuit. 150 and the mechanism control circuit 154 for controlling the loader control circuit 152, the vacuum exhaust control circuit 156 for controlling the vacuum exhaust of the vacuum exhaust device 70, and the information input unit 158 for inputting information on the property and shape of the substrate 2. A memory 160 that is a storage unit for storing input information and other plural information, a program memory 162 that stores a control program for performing various controls, and a CPU that controls each of these units, for example And the control unit 170 formed by the above.

  The position control calculation unit 300 will be described with reference to FIG. As shown in FIG. 9, the position control calculation unit 300 of the electron beam drawing apparatus 1 calculates a drawing pattern end point error and controls the calculation unit 301 for calculating drawing conditions and the high-precision deflection unit 112b. A high-precision D / A converter (position DAC) 302 that converts and controls a digital signal to an analog signal, and the attenuation factor of the variable attenuator 307 transmitted from the arithmetic unit 301 to designate the attenuation factor of the variable attenuator 307 An ATTD / A converter 303 that converts a signal related to a digital signal into an analog signal, a counter circuit 304 that counts the number of scanning clocks (count) of a high-speed D / A converter (scan DAC) 306, and an operation of the arithmetic unit 301 Based on the result, the clock generation circuit 305 for setting the number of scanning clocks of the high-speed D / A converter 306 and the high-speed deflection unit 112a are controlled. Therefore, a high-speed D / A converter 306 that converts and controls a digital signal to an analog signal, and line segment data output from the high-speed D / A converter 306 are attenuated according to a predetermined attenuation factor calculated by the arithmetic unit 301. And a variable attenuator 307.

  The high-speed D / A converter 306 processes, for example, with 12 bits, and the high-precision D / A converter 302 processes, for example, with 16 bits or 18 bits. In the case of drawing the same line, it is possible to draw at high speed by driving the deflector 20 by the high-speed D / A converter 306, and high accuracy by driving the deflector 20 by the high-speed D / A converter 302. Can be drawn.

  The high-precision D / A converter 302 includes a high-precision XD / A converter 302a that controls the position of the X component of the line to be drawn and a high-precision YD / A that controls the position of the Y component of the line to be drawn. A converter 302b. The variable attenuator 307 includes a variable attenuator (X) 307a that attenuates the X component of the line to be drawn and a variable attenuator (Y) 307b that attenuates the Y component of the line to be drawn. The ATTD / A converter 303a converts and controls the signal related to the attenuation rate transmitted from the computing means 301 from a digital signal to an analog signal in order to designate the attenuation rate of the variable attenuator (X) 307a. A converter 303a and an ATTYD / A converter 303b that controls the conversion of the signal related to the attenuation factor transmitted from the arithmetic unit 301 from a digital signal to an analog signal in order to designate the attenuation factor of the variable attenuator (Y) 307b. It is configured. By controlling the position control calculation unit 300, it is possible to perform position control of a line segment drawn from an arbitrary start point to an end point on the base material 2, thereby realizing drawing as shown in FIGS.

  In the electron beam drawing apparatus 1 having the above-described configuration, when the base material 2 transported by the loader 40 is placed on the XYZ stage 30, the air in the lens barrel 10 and the casing 11 is evacuated by the vacuum exhaust device 70. After exhausting dust and dust, an electron beam is irradiated from the electron gun 12.

  The electron beam irradiated from the electron gun 12 is deflected by the deflector 20 through the electron lens 16 and is deflected by the deflected electron beam B (hereinafter, only with respect to the electron beam whose deflection is controlled after passing through the electron lens 16, “ Drawing may be performed by irradiating the drawing position on the surface of the base material 2 on the XYZ stage 30, for example, the curved surface portion (curved surface) 2a.

  At this time, the drawing position on the substrate 2 (at least the height position among the drawing positions) or the position of a reference point as will be described later is measured by the measuring device 80, and the control circuit 100 is based on the measurement result. The position of the focal depth of the electron beam B, that is, the focal position is controlled by adjusting and controlling the respective current values flowing through the coils 17a, 17b, 17c, etc. of the electron lens 16, so that the focal position becomes the drawing position. The movement is controlled.

  Alternatively, based on the measurement result, the control circuit 100 controls the stage driving unit 50 to move the XYZ stage 30 so that the focal position of the electron beam B becomes the drawing position.

  In this example, the control may be performed by either one of the electron beam control and the XYZ stage 30 control, or by using both.

  The measuring device 80 will be described with reference to FIG. The measuring device 80 includes a laser oscillator 82 and a light receiving unit 84.

  The laser oscillator 82 irradiates the substrate 2 with the first light beam S1 from the direction intersecting the electron beam and receives the light beam S1 reflected from the flat portion 2a of the substrate 2 to detect a change in the reflection position. Is done.

  At this time, as shown in FIG. 10, since the light beam S1 is reflected by the flat portion 2a of the base material 2, the (height) position on the flat portion 2a of the base material 2 based on the change of the reflection position. Will be measured and calculated.

  Accordingly, the focal position of the electron beam is adjusted based on the height position of the base material 2, and then drawing is performed.

  11 and 12 show a comparison between the surface (a) of the substrate formed by the conventional electron beam drawing method and the surface (b) of the substrate formed by the electron beam drawing method of the present embodiment. . When drawing is performed by the conventional electron beam drawing method as shown in FIG. 1, it can be seen that a high peak is formed at the position indicated by the arrow on the surface of the substrate. On the other hand, when drawing is performed by the electron beam drawing method of the present embodiment as shown in FIGS. 2 to 4, the large peak disappears, and the surface roughness is also halved compared to that of the prior art, clearly. It can be seen that the quality of the substrate is improved.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, the beam writing method of the present invention is applicable not only to electron beams but also to other beams. Further, the present invention can be applied not only to a mold for molding an optical element but also to various kinds of drawing.

It is the schematic which showed the scanning of the electron beam at the time of performing electron beam drawing by the step and repeat system by a prior art. It is the schematic which showed the scanning of the electron beam at the time of performing electron beam drawing by the step and repeat system by the example of 1st this invention. It is the schematic which showed the scanning of the electron beam at the time of performing electron beam drawing by the step and repeat system by the example of 2nd this invention. It is the schematic which showed the scanning of the electron beam at the time of performing electron beam drawing by the step and repeat system by the example of the 3rd this invention. It is explanatory drawing which shows an example of schematic structure of the base material of this invention. It is explanatory drawing which shows the principal part of the base material of FIG. 5 in detail. It is a schematic sectional drawing of a diffraction ring zone. It is explanatory drawing which shows the schematic structure of the whole beam drawing apparatus of this invention. 3 is a block diagram showing a position control calculation unit 300. FIG. It is explanatory drawing for demonstrating the principle of a measuring apparatus. It is an enlarged photograph of the substrate surface (a) on which electron beam drawing has been performed by the electron beam drawing method according to the prior art and the substrate surface (b) on which electron beam drawing has been performed by the electron beam drawing method according to the present embodiment. The roughness of the substrate surface (a) on which the electron beam is drawn by the electron beam drawing method according to the prior art and the surface of the substrate (b) on which the electron beam is drawn by the electron beam drawing method according to the present embodiment are three-dimensionally measured. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electron beam drawing apparatus 2 Base material 2a Flat part 3 Blaze 3a Side wall part 3b Inclination part 3c Groove part 10 Lens barrel 11 Case 12 Electron gun 14 Slit 16 Electron lens 17a Coil 17a Each coil 18 Aperture 20 Deflector 22 Correction coil 30 Stage 40 Loader 50 Stage drive means 52 X direction drive mechanism 54 Y direction drive mechanism 56 Z direction drive mechanism 58 θ direction drive mechanism 60 Loader drive device 70 Vacuum evacuation device 80 Measurement device 82 Laser oscillator 84 Light receiving unit 100 Control circuit 102 Electron gun Power supply unit 104 Electron gun control unit 106 Lens power supply unit 108 Lens control unit 112a High-speed deflection unit 112b High-precision deflection unit 118 Electric field control circuit 120 Pattern generation circuit 134 Laser output control circuit 140 Measurement calculation unit 150 Stage control circuit 152 Control circuit 154 Mechanism control circuit 156 Vacuum exhaust control circuit 158 Information input unit 160 Memory 162 Program memory 170 Control unit 300 Position control calculation unit 301 Calculation means 302 High precision D / A converter 302a High precision XD / A converter 302b High precision YD / A converter 303 ATTD / A converter 303a ATTXD / A converter 303b ATTYD / A converter 304 Counter circuit 305 Clock generation circuit 306 High-speed D / A converter 307 Variable attenuator 307a Variable attenuator (X)
307b Variable attenuator (Y)

Claims (5)

In an electron beam drawing method for drawing by scanning an electron beam,
A first step of positioning a first starting point of the electron beam;
A second step of scanning in a predetermined scanning direction while irradiating the electron beam from the first start point;
A position where a second start point for starting another electron beam scan is shifted from the first start point by a first predetermined amount in the predetermined scanning direction and in a direction orthogonal to the predetermined scanning direction; And a third step
A fourth step of scanning in the predetermined scanning direction while irradiating the electron beam from the second starting point;
Further, a third starting point for starting scanning of another electron beam is shifted from the second starting point in the predetermined scanning direction by a second predetermined amount different from the first predetermined amount, and in the predetermined scanning direction. A fifth step with a position shifted in a direction orthogonal to
And a sixth step of scanning in the predetermined scanning direction while irradiating the electron beam from the third starting point. In an electron beam drawing method for drawing by scanning an electron beam,
Every time the counter counts up one by one from the first starting point where the position in the predetermined scanning direction is determined by the count value (k + 0) when k is an arbitrary integer and n is an integer of 2 or more, A first step of moving the electron beam to a position corresponding thereto in the predetermined scanning direction and scanning the electron beam to a first end point determined by a count value (k + n);
A second step of determining a position of a second start point for starting scanning of another electron beam in a direction perpendicular to the predetermined scanning direction to be different from a position of the first start point;
When m is an arbitrary integer different from k, every time the counter sequentially counts up one by one from the second starting point where the position in the predetermined scanning direction is determined by the count value (m + 0) A third step of moving the electron beam to a predetermined position in a predetermined scanning direction and scanning the electron beam to a second end point determined by a count value (m + n).   The position in the predetermined scanning direction at the second starting point is shifted from the predetermined scanning direction position at the first starting point by an amount determined by a count value (km). Item 3. The electron beam drawing method according to Item 2. In an electron beam drawing method for drawing by scanning an electron beam,
A first step of positioning a first starting point of the electron beam;
A second step of scanning in a predetermined scanning direction from the first start point to the first end point while irradiating the electron beam;
A third step in which a second start point for starting another electron beam scan is shifted from the first end point in a direction crossing the predetermined scanning direction;
And a fourth step of scanning in the direction opposite to the predetermined scanning direction while irradiating the electron beam from the second starting point. The resolution of the D / A converter used for positioning the starting point of the electron beam is higher than the resolution of the D / A converter used for scanning the electron beam. The electron beam drawing method described in 1.

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