JP2008134482A - Electron beam drawing method, electron beam drawing device, and program to control electron beam drawing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fast and dynamically change an exposure dose of an electron beam which is made thinner so as to draw a fine image with an electron beam. <P>SOLUTION: An electron beam drawing method includes exposing a substrate having a photosensitive layer by moving an electron beam in a drawing direction. The substrate 1 is irradiated with the electron beam while the electron beam is subjected to blanking at a predetermined blanking frequency, as well as the electron beam is relatively moved to oscillate forward and backward in the drawing direction. The movement of oscillation forward and backward is carried out at a frequency higher than the blanking frequency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electron beam drawing method, an electron beam drawing apparatus, and a program for controlling the electron beam drawing apparatus.

  In recent years, optical information recording media have been desired to form fine grooves as the recording density increases. In order to manufacture an optical information recording medium, for example, an optical disc, a stamper for making a resin substrate having a fine groove formed is required, and a stamper master for manufacturing this stamper is required. The stamper and the stamper original plate are required to have a fine and highly accurate groove structure corresponding to the resin substrate.

Conventionally, drawing with an electron beam is used as a method for forming such a groove.
For example, Patent Document 1 discloses a technique for changing the intensity of an electron beam according to the distance from the center of rotation of the substrate.
Further, Patent Document 2 discloses a technique for adjusting an exposure amount by blanking an electron beam.

JP 2006-138923 A JP 2003-51437 A

By the way, as described in Patent Document 1, by changing the intensity of the electron beam, the substrate can be uniformly exposed and the exposure time can be shortened. That is, it is not easy to change the apparatus while it is operating.
In this regard, if the exposure amount is adjusted by blanking as described in Patent Document 2, the intensity of the electron beam can be dynamically changed. However, unless blanking is performed at a sufficiently high blanking frequency. It can only be exposed intermittently. In other words, the exposure speed is limited to a low value in accordance with the limit of the blanking frequency.
Further, in order to form a finer groove on the stamper master, drawing with thinner lines is required.

  The present invention has been made in view of the background as described above. In order to enable fine drawing with an electron beam, the exposure amount of the electron beam can be dynamically changed at a finer and higher speed. An object is to provide an electron beam drawing method and apparatus, and a program for controlling the electron beam drawing apparatus.

  The present invention, which has solved the above-mentioned problems, is an electron beam drawing method for performing exposure while moving an electron beam relative to the drawing direction on a substrate provided with a photosensitive layer, wherein the electron beam has a predetermined blanking frequency. Irradiating the substrate while blanking at the same time, moving the electron beam relatively to vibrate back and forth in the drawing direction, and moving to vibrate back and forth is higher than the blanking frequency. It is performed by frequency.

According to such an exposure method, it is possible to dynamically adjust the intensity of the electron beam while generating the electron beam by blanking. Moreover, since the irradiation position of the electron beam is moved so as to vibrate back and forth in the relative movement direction of the substrate, in other words, the drawing direction at a frequency higher than the blanking frequency, the electron beam moves so as to trace the exposure line, Exposure lines do not become intermittent due to blanking. Therefore, exposure can be performed while relatively moving the substrate at a higher speed than when only blanking is performed. In addition, by such a method, the intensity of the electron beam itself can be reduced while keeping the intensity of the electron beam itself constant, so that it is possible to draw with a thin line and form a fine groove in the manufacture of a stamper master or the like. Can contribute.
Note that the back-and-forth movement here means moving back and forth in the drawing direction.

  In the above-described method, the movement to vibrate back and forth can be performed by deflecting the electron beam to vibrate in the relative movement direction, and the substrate is moved with respect to the electron beam. It can also be done by moving it.

In the above method, the relative velocity of the substrate with respect to the electron beam is A (m / s), the blanking frequency is fb (1 / s), the deflection frequency of the electron beam is fa (1 / s), When the amplitude of the deflection of the electron beam in the relative movement direction on the substrate is B (m),
A / fb <B (1)
And 2fb <fa (2)
It is desirable to satisfy.
Here, A / fb means the distance that the substrate moves relative to the electron beam generator during one blanking period, or the distance that the electron beam moves relative to the substrate. Therefore, by satisfying the expression (1), the irradiation direction of the electron beam is deflected with a width enough to cover the range exposed during one cycle.
Equation (2) defines that the deflection frequency fa is a certain degree higher than the blanking frequency fb, and the exposure line is traced about twice or more with an electron beam during one blanking period. Becomes uniform and high-precision exposure is possible.

  Further, in order to solve the problems of the present invention, an electron beam lithography apparatus for exposing a substrate provided with a photosensitive layer with an electron beam, the electron beam generating apparatus for generating the electron beam, and the electron beam with respect to the electron beam In order to relatively move the substrate, the electron beam or a moving device that moves the substrate, and a control device that controls blanking of the electron beam and an irradiation position on the substrate, the control device includes the electron beam Irradiating while blanking a line at a predetermined blanking frequency, moving the electron beam relatively to vibrate back and forth in the drawing direction, and moving to vibrate back and forth is performed by the blanking. It is characterized by being performed at a frequency higher than the frequency.

  According to such an apparatus, the above-described method can be realized, and exposure with a fine and highly accurate electron beam can be performed at high speed.

  In this electron beam drawing apparatus, the moving device includes a deflector that deflects the irradiation direction of the electron beam, and the control device deflects the electron beam to vibrate in the relative moving direction. Movement that vibrates in the front-rear direction can be performed. In addition, the control device can also move the substrate so as to vibrate back and forth by moving the substrate relative to the electron beam.

In the electron beam lithography apparatus, the relative speed of the substrate with respect to the electron beam is A (m / s), the blanking frequency is fb (1 / s), and the deflection frequency of the electron beam is fa (1 / S), when the amplitude of the deflection of the electron beam in the relative movement direction on the substrate is B (m), the control device
a / fb <B
And 2fb <fa
It is desirable to control the blanking and irradiation direction of the electron beam so as to satisfy.

  Further, in the above-described electron beam drawing apparatus, the moving device includes a rotating device that rotates the substrate, and the control device increases the blanking ratio as the distance from the rotation center of the substrate decreases. Therefore, it is desirable to reduce the exposure amount.

  By doing in this way, even if a board | substrate is rotated at equal speed, the exposure intensity | strength by an electron beam can be made uniform on the whole board | substrate.

  Furthermore, the present invention provides an electron beam generator that generates an electron beam, a deflector that deflects the irradiation direction of the electron beam, a moving device that supports the substrate and moves the substrate relative to the electron beam, A program for controlling an electron beam drawing apparatus that performs exposure with an electron beam on a substrate provided with a photosensitive layer, and a control device that controls the blanking and irradiation direction of the electron beam, Functions as blanking means for irradiating the electron beam with blanking at a predetermined blanking frequency, and deflecting means for deflecting the irradiation direction of the electron beam so as to vibrate back and forth in the drawing direction at a frequency higher than the blanking frequency. It is also possible to configure as a program to be executed.

  According to the present invention, exposure with a fine and highly accurate electron beam can be performed at high speed, and the intensity of the electron beam can be dynamically changed.

  Next, an electron beam drawing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view (a) and a plan view (b) of an essential part of an electron beam lithography apparatus according to an embodiment of the present invention.

As shown in FIG. 1A, an electron beam drawing apparatus 10 includes an electron beam irradiation apparatus 20 that irradiates an electron beam onto a substrate 1, and a substrate movement apparatus (rotation) as an example of a movement apparatus that rotates and moves the substrate 1. Device) 30 and a control device 40 for controlling the operation of the electron beam irradiation device 20 and the substrate moving device 30.
The substrate 1 is a circular substrate coated with an electron beam resist solution, and is rotated in the direction of arrow R shown in FIG.
The substrate moving device 30 includes a rotary stage unit 31 and a linear moving device 35 that moves the rotary stage unit 31 forward and backward in the Y direction of FIG. 1B, that is, in the radial direction of the substrate 1.

The rotary stage unit 31 includes a circular stage 32 and a spindle motor 33. The stage 32 is formed of a horizontally installed disc, and the substrate 1 is placed with its center aligned with the rotation center 34 of the stage 32.
The spindle motor 33 is a motor that rotates the stage 32 around a vertical axis, and the motor axis is fixed to the center of the stage 32.

  The linear moving device 35 includes a shaft 36 extending in the Y direction, a screw shaft 37 supported by the shaft 36 along the shaft 36, and a pulse motor 38 that rotates the screw shaft 37 in the forward direction or the reverse direction. . The screw shaft 37 is engaged with the spindle motor 33 to constitute a ball screw mechanism, and the spindle motor 33 can move in the Y direction by the rotation of the pulse motor 38.

  The electron beam irradiation device 20 includes an electron gun 21 as an electron beam generator that emits an electron beam EB, and a deflector 22 as an example of a moving device that deflects the electron beam EB in the Y direction (radial direction of the substrate 1). A deflector 23 that deflects in the X direction (circumferential direction) orthogonal to the Y direction and an electron optical system 24 that focuses the electron beam EB on the substrate 1 are provided. Thereby, the electron beam EB emitted from the electron gun 21 is irradiated onto the substrate 1 through the deflectors 22 and 23 and the electron optical system 24.

  As shown in FIG. 2, the electron optical system 24 includes an adjustment electron lens 24a that adjusts the irradiation energy of the electron beam EB onto the substrate 1, and an aperture 24b that narrows the electron beam EB that has passed through the adjustment electron lens 24a. The electron beam EB that has passed through the aperture 24b is focused on the substrate 1 and a correcting electron lens 24c that corrects astigmatism. Each of the adjustment electron lens 24a and the correction electron lens 24c includes a plurality of coils that generate a magnetic field when a current flows. The adjustment electron lens 24a and the correction electron lens 24a are controlled by controlling the current flowing through the coils. The intensity of the electron lens 24c is controlled.

Each of the deflectors 22 and 23 is provided with a coil, and a magnetic field is generated by passing a current through each coil, and the electron beam EB can be bent in the Y direction and the X direction, respectively. Note that the deflectors 22 and 23 may generate an electric field by applying a voltage and bend the electron beam EB.
The deflectors 22 and 23 can also be used as a device for intermittently irradiating the electron beam EB, that is, blanking. If a strong magnetic field for bending the electron beam EB is generated in the deflector 22 or the deflector 23, the electron beam EB is blocked by the aperture 24b and does not reach the substrate 1. Therefore, the electron beam EB can be blanked by outputting a signal having an appropriate intensity to the deflectors 22 and 23 in a pulsed manner.
Instead of using the aperture 24b of the electron optical system 24 as a blanking blocking wall, a diaphragm for blocking the electron beam EB may be provided directly below the deflectors 22 and 23. Further, a device for deflecting the electron beam EB for blanking may be provided separately from the deflectors 22 and 23.

  The electron gun 21, the deflectors 22 and 23, the electron optical system 24, and the substrate moving device 30 are each connected to the control device 40, and the operation is controlled by inputting signals for controlling each device from the control device 40. Is done.

Although not shown, the control device 40 includes a storage device including a CPU, a ROM, and a RAM, and a driver for outputting signals to each device, and appropriately reads and executes a program stored in the storage device so that each device can be read. The control signal is output.
Therefore, the control device 40 can draw a desired pattern such as a concentric pattern or a spiral pattern on the substrate 1 by controlling the timing of driving the spindle motor 33 and the pulse motor 38. it can.

  In the electron beam drawing apparatus 10 of the present embodiment, both the blanking and deflection of the electron beam EB are performed by the deflectors 22 and 23, and the control device 40 has a blanking means 41 for blanking. And a program for causing the control device 40 to function as the deflecting means 42 for deflecting at a high frequency.

The blanking means 41 is configured to output a large pulse voltage at a predetermined frequency to the deflector 22 in order to greatly swing the electron beam EB in the Y direction in FIG. Needless to say, the predetermined frequency does not have to be constant and can be dynamically changed according to the exposure position. The blanking ratio (duty ratio) can also be dynamically changed according to the exposure position. For example, by increasing the blanking ratio proportionally as the exposure position is away from the rotation center of the substrate 1 (smaller distance), the exposure amount can be reduced and a uniform exposure amount can be obtained for the entire stamper original. it can.
Further, the direction in which the electron beam EB is greatly shaken for blanking is not limited to the Y direction, and may be the X direction.

The deflecting means 42 vibrates the electron beam EB back and forth at a frequency higher than the blanking frequency of the electron beam EB in the X direction in FIG. 1B, that is, the relative movement direction (drawing direction) of the substrate 1 with respect to the electron beam EB. It is a means to deflect. That is, the electron beam EB moves so as to swing. Therefore, the deflection means 42 is configured to output a low-speed and high-speed pulse signal to the deflector 23.
In this embodiment, since the substrate 1 is rotating, the X direction and the relative movement direction of the substrate 1 with respect to the electron beam EB do not exactly coincide with each other. Since the amplitude of the electron beam EB is smaller than the rotation radius of the exposed point on the substrate 1, the arc that is the locus of this point can be regarded as a straight line.

The amplitude B (m) for oscillating the electron beam EB by the deflecting means 42 is A (m / s) for the relative speed of the substrate 1 with respect to the electron beam EB, fb (1 / s) for the blanking frequency, and the deflection frequency for the electron beam. Is fa (1 / s),
A / fb <B
It is good to satisfy. The relative speed A is a relative speed with respect to the case where the electron beam EB is not vibrated.
Further, the blanking frequency fb and the deflection frequency fa need to satisfy fb <fa at a minimum, but preferably 2fb <fa
It is good to satisfy. Thus, during one blanking, the range in which the substrate 1 moves relatively during the blanking is traced about twice with the electron beam EB (depending on the duty ratio of the blanking signal). Unevenness of drawing can be reduced.

An electron beam drawing method using the electron beam drawing apparatus 10 as described above will be described.
When drawing an electron beam, an electron beam resist solution is applied to the surface of the substrate 1 to provide a photosensitive layer, and the photosensitive layer is fixed on the stage 32 so that the photosensitive layer is on the upper side.
Then, the control device 40 controls the spindle motor 33 to rotate the stage 32 at a constant speed, while sending a control pulse to the pulse motor 38 to rotate the electron beam EB from the inner peripheral side to the outer peripheral side of the substrate 1. The rotary stage unit 31 is moved so that the substrate 1 is irradiated spirally.

The control device 40 generates an electron beam EB from the electron gun 21 and sends a pulse signal to the deflectors 22 and 23 by the blanking means 41 and the deflecting means 42.
That is, as shown in FIG. 3A, a pulse signal is sent as a blanking signal with a large amplitude and a relatively low frequency, and a deflection signal is pulsed with a smaller amplitude and a higher frequency than the blanking signal. Send a signal.
The blanking signal is sent to one or both of the deflectors 22 and 23, and the deflection signal is sent to the deflector 23.
Note that the difference in amplitude between the blanking signal and the deflection signal is not an indispensable condition because they are sent to the deflectors 22 and 23 having the same performance. When a blanking deflector is provided separately, a blanking signal having an amplitude suitable for the deflector may be used.

With this blanking signal and deflection signal, the drawing pattern can be a continuous and thin pattern as shown in FIG.
Further, in the case of the present embodiment (in the case of FIG. 3A), the reason why the line width of the drawing pattern becomes narrow even with the same beam diameter is that the energy distribution of the cross section of the electron beam EB is higher in the center, This is because it is weak. Since the electron beam EB is weakened as a whole, the portion having an energy capable of sufficiently exposing the photosensitive layer is only near the center, and the line width is narrowed.

The effect of this embodiment will be described in comparison with a case where electron beam drawing is performed by a conventional method. FIG. 3B shows a case in which neither blanking nor deflection to vibrate is performed, and drawing is performed with a thick line although it is continuous.
In addition, as shown in FIG. 3C, when only blanking is performed and deflection for vibration is not performed, the drawing pattern is intermittent with a thick line. Of course, when the blanking frequency is sufficiently high with respect to the velocity of the substrate 1 with respect to the electron beam EB, the pattern does not become intermittent as shown in FIG. When the substrate 1 is rotated at a high speed above a certain level, a difference between the intermittent pattern and the continuous pattern as shown in FIGS. 3A and 3C appears.

  In this way, the electron beam EB can be weakened by blanking, and the drawing pattern can also be thinned. Such a change in drawing thickness can be dynamically changed by changing the duty ratio of the blanking signal while irradiating the electron beam EB. Therefore, the present invention can be suitably used when it is desired to change the intensity of the electron beam EB according to the distance from the rotation center 34 of the substrate 1. Further, by only blanking the electron beam EB, the electron beam EB is vibrated in the relative movement direction (drawing direction) of the substrate 1 even if the speed of the substrate 1 is so high that the drawing pattern becomes intermittent. Therefore, a continuous drawing pattern can be formed, and as a result, high-speed drawing is possible.

As described above, according to the electron beam drawing apparatus 10 and the electron beam drawing method according to the embodiment of the present invention, the electron beam EB can be weakened, and the exposure with the fine and highly accurate electron beam EB can be performed at high speed. it can. In addition, the intensity of the electron beam can be changed dynamically.
INDUSTRIAL APPLICABILITY The method and apparatus of the present invention are effective for manufacturing a stamper master for optical information recording media having fine grooves with a groove width of 80 to 180 nm and a depth of 60 nm or less, and stampers having two or more different groove widths. In the case of manufacturing an original plate, the line width, that is, the groove width can be changed while the electron beam drawing apparatus 10 is in operation, so that it can be used particularly effectively.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.
For example, the drawing of the spiral on the substrate 1 may be performed not only from the inner periphery of the substrate 1 but also from the outer periphery.
Moreover, not only when rotating the board | substrate 1, you may draw a straight line and a curve by moving in parallel. In this case, the relative movement of the electron beam in the drawing direction is not only performed by fixing the position of the electron beam and moving the substrate 1 in parallel, but also relative to vibrate the electron beam in the drawing direction. The substrate 1 may be moved by parallel movement so as to vibrate the substrate 1 finely.
The moving device may be any device that moves the relative position between the electron beam EB and the substrate. Therefore, the moving device is not limited to the device that moves the substrate 1, and the deflector 22 that fixes the substrate 1 and moves the electron beam EB. 23 may be used as a moving device for determining the drawing direction. That is, it is possible to perform drawing while displacing the irradiation position of the electron beam EB by controlling the current sent to the deflectors 22 and 23 while the substrate 1 is fixed.

A spiral groove pattern was drawn with an electron beam by using a blanking signal and a deflection signal when a stamper master for an optical information recording disk was manufactured by the same electron beam drawing apparatus as in the above-described embodiment.
The drawing conditions at this time were as follows.
Linear velocity (relative velocity of the substrate with respect to the electron beam) 0.5 m / s
Blanking frequency fb 1MHz
Duty ratio of blanking signal 50%
Electron beam deflection frequency fa 10MHz
Amplitude of deflection 1μm

  As a result, a continuous groove pattern with a line width of 140 nm could be drawn.

It is the principal part side view (a) and top view (b) of the electron beam drawing apparatus which concern on embodiment. It is detail drawing explaining an electron beam optical system. It is a figure showing the relationship between a blanking signal, a deflection signal, and a drawing pattern. When (a) is the present embodiment, (b) is when neither a blanking signal nor a deflection signal is used, (c) is a blanking signal. The case where only is used is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 10 Electron beam drawing apparatus 20 Electron beam irradiation apparatus 21 Electron gun 22 Deflector 23 Deflector 24 Electron optical system 30 Moving apparatus 40 Control apparatus 41 Blanking means 42 Deflection means EB Electron beam

Claims (10)

An electron beam drawing method for performing exposure while moving an electron beam relative to a drawing direction on a substrate provided with a photosensitive layer,
While irradiating the substrate while blanking the electron beam at a predetermined blanking frequency, moving the electron beam relatively back and forth in the drawing direction, and vibrating back and forth. The electron beam drawing method, wherein the movement is performed at a frequency higher than the blanking frequency.   2. The electron beam drawing method according to claim 1, wherein the movement for vibrating back and forth is performed by deflecting the electron beam so as to vibrate in the relative movement direction.   2. The electron beam drawing method according to claim 1, wherein the movement for vibrating back and forth is performed by moving the substrate with respect to the electron beam. The relative speed of the substrate with respect to the electron beam is A (m / s), the blanking frequency is fb (1 / s), the deflection frequency of the electron beam is fa (1 / s), and the relative movement of the electron beam When the amplitude of the deflection in the direction on the substrate is B (m),
A / fb <B
And 2fb <fa
The electron beam drawing method according to any one of claims 1 to 3, wherein: An electron beam lithography apparatus that performs exposure with an electron beam on a substrate provided with a photosensitive layer,
An electron beam generator for generating the electron beam;
A moving device for moving the electron beam or the substrate in order to move the substrate relative to the electron beam;
A control device for controlling the blanking of the electron beam and the irradiation position on the substrate;
The controller is
The electron beam is irradiated while being blanked at a predetermined blanking frequency, the electron beam is relatively moved so as to vibrate back and forth in the drawing direction, and the movement that vibrates back and forth is performed as described above. An electron beam drawing apparatus characterized by being performed at a frequency higher than a blanking frequency. Including a deflector for deflecting an electron beam irradiation direction as the moving device;
6. The electron beam drawing apparatus according to claim 5, wherein the control device moves the electron beam so as to vibrate in the front-rear direction by deflecting the electron beam so as to vibrate in the relative movement direction. .   The electron beam drawing apparatus according to claim 5, wherein the control device moves the substrate relative to the electron beam to vibrate forward and backward. The relative speed of the substrate with respect to the electron beam is A (m / s), the blanking frequency is fb (1 / s), the deflection frequency of the electron beam is fa (1 / s), and the relative movement of the electron beam When the amplitude of the deflection in the direction on the substrate is B (m),
The controller is
A / fb <B
And 2fb <fa
The electron beam drawing apparatus according to any one of claims 5 to 7, wherein blanking and irradiation directions of the electron beam are controlled so as to satisfy the following conditions. The moving device includes a rotating device that rotates the substrate,
9. The control device according to claim 5, wherein the control device reduces the exposure amount by increasing the blanking ratio as the distance from the rotation center of the substrate is smaller. Electron beam drawing device. An electron beam generating device for generating an electron beam; a deflector for deflecting an irradiation direction of the electron beam; a moving device for supporting the substrate and moving the substrate relative to the electron beam; and blanking of the electron beam And a control device for controlling the irradiation direction, and a program for controlling an electron beam drawing apparatus that performs exposure with an electron beam on a substrate provided with a photosensitive layer,
The control device;
Blanking means for irradiating the electron beam with blanking at a predetermined blanking frequency;
A program that functions as a deflection unit that deflects the irradiation direction of the electron beam so as to vibrate back and forth in a drawing direction at a frequency higher than the blanking frequency.

Images