JP4532185B2 - Electron beam drawing method - Google Patents

Description

  The present invention relates to an electron beam drawing method for drawing and exposing elements constituting a transfer pattern by irradiating an electron beam onto a resist provided on a disk for forming a concave / convex pattern when a magnetic transfer master carrier is produced. It is about.

  Conventionally, a magnetic field for transfer is applied to a master carrier by applying a magnetic field for transfer in a state in which a magnetic transfer master carrier carrying transfer information by a fine uneven pattern of a magnetic material and a slave medium having a magnetic recording unit that receives the transfer are in close contact. There is known a magnetic transfer method for transferring and recording a magnetization pattern corresponding to information (for example, a servo signal) carried on a slave medium.

  As a method for producing a master carrier used in this magnetic transfer, an optical disc stamper producing method, which is produced based on a master having a concavo-convex pattern formed by a resist corresponding to information to be transferred, is considered. (For example, refer to Patent Document 1).

  When manufacturing the optical disc stamper, the data is converted into pit lengths while rotating the resist-coated disc (glass plate, etc.), and the data irradiated with the laser beam modulated accordingly is applied to the resist. It has been written.

  Also, in the magnetic transfer master carrier, fine patterns are drawn by irradiating a laser beam modulated in accordance with the information to be transferred while rotating a resist-coated disk, as in the case of the optical disperser. It is generally considered to form.

  However, magnetic disk media have been reduced in size and increased in capacity, and when the bit length or track width becomes narrow in response to an increase in recording density (for example, the bit length or track width is 0.3 μm or less). Then, the limit of the drawing diameter is approached with the laser beam, and the shape of the end of the drawn portion becomes an arc shape, making it difficult to form a rectangular element of the pattern. The top surface shape of each element constituting the pattern formed on the master carrier is a shape corresponding to the drawn part, and when the end part shape of the drawn part is an arc shape, the master carrier The shape of the upper surface of the convex portion of the concave / convex pattern of the substrate becomes a shape greatly deviated from a rectangle such as an arc shape, and it becomes difficult to form a desired magnetization pattern on the slave medium.

  On the other hand, in the semiconductor field, patterning using an electron beam that can be exposed with a spot having a diameter smaller than that of a laser beam has already been performed. By using this electron beam, it is possible to pattern a fine pattern with high accuracy. It has become to.

In the production of patterned media, which is expected to be realized as a small and lightweight high-density magnetic recording medium, it has been proposed to perform pattern exposure with an electron beam (see, for example, Patent Document 2).
JP 2001-256644 A JP 2001-110050 A

  By the way, in this magnetic transfer, recording a servo pattern corresponding to a servo signal in each sector of a circumferential track as a transfer pattern requires a long time for recording by a magnetic head of a conventional servo track writer. On the other hand, it has a remarkable characteristic in that it can be simultaneously recorded in a short time on the entire disk surface.

  However, the servo signal, for example, as a burst signal for head positioning, in addition to the preamble (synchronization signal) and gray code (track number identification signal) recorded to the full width of the track, is recorded on one half of the track width. Similarly, the transfer pattern (concave / convex pattern formed of magnetic material) formed on the magnetic transfer master carrier in order to transfer and record the servo signal includes a signal to be recorded, and the convex portion is formed to the full track width. There is a first element corresponding to the preamble and the gray code, and a second element corresponding to the burst signal in which a convex portion corresponding to a half track is arranged. It is necessary to draw the elements of the transfer pattern one by one efficiently and accurately.

  Since the above-described magnetic transfer master carrier needs to be patterned concentrically, a good pattern can be obtained by simply applying the electron beam writing method using an XY stage, which is used in the field of semiconductors. Since formation is difficult, an electron beam writing method capable of good pattern drawing is desired. In particular, the drawing of the second element for the half track described above cannot be performed in the same manner as the first element, and thus needs to be devised. As the number of tracks (number of sectors) increases, the number of elements increases. Therefore, it is desired to shorten the drawing time by improving the drawing speed and to improve the drawing shape and drawing position accuracy in the entire area of the disk.

  In view of the above circumstances, the present invention provides an electron beam writing method capable of drawing a fine pattern including a first element having a track width and a second element corresponding to a half track on the entire surface of a disk with high accuracy and at high speed. It is intended to do.

In the electron beam drawing method of the present invention, the transfer pattern of the magnetic transfer master carrier is drawn on the disk placed on the rotary stage coated with a resist and movable in the radial direction while rotating the rotary stage. An electron beam drawing method for drawing an element constituting a transfer pattern by scanning an electron beam irradiated from an apparatus,
The transfer pattern has a first element arranged in a track width and a second element arranged in a half of the track width in a transfer region of each sector of a circumferential track,
The electron beam drawing apparatus includes a deflection unit that deflects an electron beam to be irradiated in a radial direction of the disk, and a blanking unit that blocks irradiation of the electron beam except for a drawing portion.
While the disk is rotated in one direction, the electron beam is deflected in the radial direction by one track by the deflection means, and the first and second elements are drawn by one track by one rotation of the disk. And
The drawing of the first element is performed by irradiating the electron beam for the deflection corresponding to the track width, while the drawing of the second element is for the half track that is not drawn out of the deflection corresponding to the track width. This deflection is performed by blocking the electron beam irradiation by the blanking means and irradiating the electron beam for the remaining half track deflection.

  In the present invention, it is preferable that the drawing length in the circumferential direction of the element is defined by an amplitude that causes the electron beam to reciprocate at high speed in a circumferential direction substantially perpendicular to the radial direction of the disk.

  The present invention is suitable when the transfer pattern is a servo pattern including a burst portion.

  The `` element constituting the pattern '' is a recording element formed for recording a signal according to information on a track, and is generally a parallelogram including a rectangular shape, a side parallel to the track direction, Surrounded by vertical or inclined edges that intersect the track direction.

  An electron beam drawing apparatus for carrying out the drawing method of the present invention includes a rotary stage that rotatably supports a disk, a mechanism that linearly moves the rotary stage, and a drive control of the rotational speed and linear movement of the rotary stage. Means for generating and emitting an electron beam, blanking means for turning on / off the electron beam irradiation, deflection means for deflecting the electron beam in the circumferential direction and in the radial direction, and a pattern Means for sending a drawing data signal for scanning the electron beam corresponding to each element, and control means for linking and controlling these operations.

  According to the electron beam writing method of the present invention, the deflection of sending the electron beam in the radial direction while rotating the disk in one direction is performed to draw the first element of the track width, and at the same time, the blanking means performs a half track. The first element and the second element for a half track can be drawn at a time by cutting off the irradiation of the electron beam for the second time and drawing the second element continuously. A fine pattern can be drawn on the entire surface at high speed and with high accuracy, and the drawing time can be shortened by improving the drawing efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A is a plan view showing a transfer pattern of a master carrier for magnetic transfer drawn by an electron beam drawing method of the present invention, and an enlarged schematic view showing a drawing method according to the first embodiment of elements constituting the transfer pattern. b) and an enlarged schematic diagram (c) showing a drawing method of an element constituting a transfer pattern according to a reference example not included in the present invention, and FIG. 2 is a drawing of a servo pattern according to the first embodiment of FIG. FIG. 3 is an enlarged schematic diagram showing the drawing order of servo patterns according to the reference example of FIG. 1 (c) . FIG. 4 is a side view (a) and a top view (b) of a main part of an electron beam drawing apparatus according to an embodiment for carrying out the electron beam drawing method of the present invention.

  As shown in FIG. 1 (a), a transfer pattern 12 (servo pattern) having a fine concavo-convex shape formed on a magnetic transfer master carrier is formed on a disk-shaped disk 11 (circular base), an outer peripheral portion 11a and an inner peripheral portion. It is formed in an annular region excluding 11b. This pattern 12 corresponds to a case where the transfer information is a servo signal, and is formed in concentric tracks on the disk 11 at narrow intervals extending in the radial direction from the central portion at equal intervals. In the case of the servo pattern 12 in this example, the servo pattern 12 is formed in a curved radial shape continuous in the radial direction.

  When a part of one pattern 12 is enlarged, as shown in FIGS. 1B and 1C and FIGS. 2 and 3, the concentric tracks T have fine fine patterns corresponding to the information to be transferred. One element 13 and a second element 14 are arranged and constituted by an aggregate thereof. The shape of the first element 13 in each track T is a rectangular shape having a width W corresponding to the track width and a length (bit length) L, and the second element 14 has a half of one side of the track width W. It has a rectangular shape and is formed continuously across the adjacent tracks with a half-track shift from the first element 13 continuously with the second elements 14 of the adjacent tracks T. In the final master carrier, the elements 13 and 14 become convex portions (or concave portions), and the other portions become flat portions (lands).

  In the servo pattern 12, the preamble (synchronization signal) and the gray code (track number identification signal) are transferred by the first element 13, and the head positioning burst signal is recorded by the second element 14. .

  Drawing of the elements 13 and 14 of the pattern 12 is performed, for example, on the outer circumference of the track on the inner circumference side while the disk 11 having the resist coated on the surface is placed on a rotating stage 41 (see FIG. 4) described below and rotated. The resist is irradiated and exposed by scanning the elements 13 and 14 with the electron beam EB one track at a time in order to the side track or in the opposite direction.

  FIG. 1B and FIG. 2 are views showing a first embodiment of the electron beam drawing method of the present invention. Drawing in this embodiment is performed by first and second elements 13 and 14 for one track. Are drawn at once by one rotation (one round) of the disk 11. While rotating the disk 11 in one direction A, a predetermined concentric track T (track width: W) extending linearly in a circumferential direction X perpendicular to the radial direction Y of the disk 11 when viewed microscopically. At the phase position, the rectangular first element 13 and the second element 14 corresponding to a half track are continuously scanned with the electron beam EB having a small diameter so as to fill the shape at a time, and one rotation makes 1 All elements 13 and 14 in the track are drawn.

  The above scanning is performed by irradiating an electron beam EB having a beam diameter smaller than the minimum width of the elements 13 and 14 while reciprocally vibrating at a constant amplitude L in the circumferential direction X substantially orthogonal to the radial direction Y, By deflecting the electron beam EB in the radial direction Y and performing the feed D with the track width W, the electron beam EB scans so that the shape of the first element 13 is filled with a triangular wave locus, and then FIG. As indicated by a broken line in b), only the deflection signal is output in a state where the electron beam EB is cut off by the off operation of the blanking means (aperture 25, blanking 26), which will be described later, and the deflection of half a track at the predetermined phase position After the interruption, the blanking means is turned on from the track center position to start the irradiation of the electron beam EB. Similarly, the electron beam EB is equivalent to the half track of the second element 14. Jo The scans as fill in the triangular locus, for drawing sequential elements 13,14. After drawing one track T once, it moves to the next track T and draws in the same manner, and a desired fine pattern 12 is drawn on the entire area of the disk 11.

  FIG. 2 shows the drawing order of the elements 13 and 14 of a plurality of tracks. First, the T1 track is drawn by aligning the Y-direction deflection center with the center of the T1 track and drawing the first and second elements 13 and 14 in the order of 1 · 1 to 1 · 8. That is, with the rotation direction A, the drawing 1 · 1, 1 · 2 of the two first elements 13 at the head of the sector is performed on the track width W, and then the drawing 1 of the second element 14 of the upper half that follows. For 3, 1 and 4, the lower half is blanked and the electron beam EB is cut off, and only the upper half is irradiated to perform scanning drawing. Subsequently, drawing 1 · 5, 1 · 6 of the second element 14 of the two lower halves is made by drawing the lower half and then blocking the electron beam EB by blanking the upper half. The drawing 1 · 7, 1 · 8 of the first element 13 is performed to the track width W.

  At the time of the next rotation, the center of deflection in the Y direction is aligned with the center of the T2 track, and the first element 13 and the second element 14 are similarly drawn using blanking in the order of 2 · 1 to 2 · 8. In the next rotation, the center of deflection in the Y direction is aligned with the center of the T3 track, and the first element 13 and the second element 14 are similarly drawn using blanking in the order of 3 · 1 to 3 · 8.

FIG. 1C and FIG. 3 are diagrams showing an electron beam drawing method of a reference example not included in the present invention. The drawing of this reference example is performed by first and second elements 13 and 14 for one track. Is drawn in half a track by two revolutions (two revolutions) by one revolution (one revolution) of the disk 11.

  That is, while rotating the disk 11 in one direction A, the half track together with the half of the rectangular first element 13 is placed at a predetermined phase position of the inner half track of the concentric track T (track width: W). The second element 14 located at the same position is drawn in the same manner, and the second element 14 located at the half track along with the remaining half of the first element 13 is placed at a predetermined position on the outer half track at the next rotation. Drawing is performed in the same manner, and all elements 13 and 14 in one track are drawn by two rotations.

  As in the previous example, the above scanning is performed by reciprocally vibrating at a constant amplitude L in the circumferential direction X substantially perpendicular to the radial direction Y while irradiating the electron beam EB having a beam diameter smaller than the minimum width of the elements 13 and 14. By swinging and deflecting the electron beam EB in the radial direction Y and feeding D with a half track width W / 2, the electron beam EB fills the half track shape of the first element 13 with a triangular wave locus. Then, as shown by a broken line in FIG. 1 (c), the electron beam is interrupted by the blanking 26, which will be described later, and the next drawing phase position is waited in a state where the electron beam is blocked. At this position, the blanking means is turned on to scan the shape of the remaining half of the first element 13 and the half track of the second element 14 so as to be filled with a triangular wave locus. For drawing of the instrument 13 and 14. This is repeated to draw one track T twice, then move to the next track T and draw in the same manner, and draw a desired fine pattern 12 in the entire area of the disk 11.

  FIG. 3 shows the drawing order of the elements 13 and 14 of a plurality of tracks. First, the drawing of the T1 track is performed by adjusting the deflection width in the Y direction to the inner half track width of the T1 track, and along the rotation direction A, the drawing 1 of the inner half of the first two elements 13 at the head of the sector.・ After performing 1, 1 and 2 to the half track width, wait for the blanking 26 to reach the phase position of the second element 14 of the next lower half, and draw at the position 1 ・ 3, 1 ・ 4 In the same way, the inner half of the subsequent two first elements 13 are drawn 1, 5, 1 and 6, and the deflection width in the Y direction is changed to the outer half of the T1 track by the next rotation. In accordance with the rotation direction A, the drawing of the outer half of the first first element 13 at the head of the sector 1 · 7, 1 · 8 is performed to the half track width, and then the second upper half of the second half is blanked. Wait until it reaches the phase position of element 14, and draw 1 ・ 9, 1 ・ 10 at that position, Make two outer periphery of the half drawing 1, 11,1, 12 of the first element 13 of the.

  At the time of the next rotation, the blanking 26 is applied to the inner half of the T2 track, and the inner half of the first element 13 and the second element 14 of this half track in the same order of 2 · 1 to 2 · 6. At the time of further rotation, the outer half track of the T2 track, the second half of the first element 13 and the second element 14 of this half track in the same order of 2 · 7 to 2 · 12 are used. Draw using blanking.

  The track movement of the electron beam EB is performed by linearly moving a rotary stage 41 described later in the radial direction Y. The movement is performed for each drawing of one track or for each drawing of a plurality of tracks in accordance with the deflectable range of the electron beam EB.

  Further, when the electron gun that emits the electron beam EB is fixed as described later, the rotary stage 41 rotates during drawing of one rectangular element 13 and 14, and the drawing locus is shifted. When the influence cannot be ignored, it is necessary to perform deflection feed D in the radial direction Y while deflecting the swing center of the reciprocal vibration (X direction) of the electron beam EB in the same direction as the rotation direction according to the rotational speed. . On the other hand, when the shape of the elements 13 and 14 of the pattern 12 is not rectangular but is a parallelogram having an angle with respect to the track direction, the center of reciprocal vibration of the electron beam EB is corresponding to the angle. A deflection feed D in the radial direction Y is performed while deflecting.

  The drawing length L in the circumferential direction X of the elements 13 and 14 is defined by the amplitude of the reciprocating vibration in the circumferential direction of the electron beam EB. When the circumferential length L of the elements 13 and 14 exceeds the deflection range of the electron beam EB, drawing is performed in a plurality of times.

  Further, with respect to the movement of the drawing position in the drawing area of the disk 11 in the radial direction, that is, the track movement, the linear velocity is the same in the entire drawing area in both the outer peripheral side and the inner peripheral side of the disk 11. It is preferable to adjust the rotation speed of the rotary stage 41 so that it is slow when drawing on the outer circumference side and fast when drawing on the inner circumference side, and drawing with the electron beam EB from the viewpoint of obtaining uniform exposure and securing the drawing position accuracy. .

  In order to draw the elements 13 and 14, the electron beam EB is scanned as described above, and a drawing data signal for performing scanning control of the electron beam EB is transmitted. The timing and phase of this transmission signal are controlled based on a reference clock signal generated according to the rotation of the rotary stage 41.

  On the other hand, when the recording method of the pattern 12 is the CAV (constant angular velocity) method, the circumferential length L of the elements 13 and 14 varies depending on the outer circumference side track as the sector length changes on the inner and outer circumferences. Thus, it is long and short on the inner track. In this case, when drawing the elements 13 and 14, the speed of the deflection feed D in the radial direction Y is changed so that the feed for drawing the outer track is slow and the feed for drawing the inner track is fast. To do. That is, the drawing area is changed so as to become slower as the distance from the rotation center of the disk 11 becomes larger, and the drawing area of the electron beam EB per unit time is made constant in each element 13, 14. Thereby, the exposure of the elements 13 and 14 can be performed evenly under the same conditions. That is, it can be performed under stable conditions in which the frequency of the reciprocal vibration in the circumferential direction of the electron beam EB is constant and the electron beam intensity is constant.

  In order to perform the above drawing, an electron beam drawing apparatus 40 as shown in FIG. 4 is used. The electron beam drawing apparatus 40 includes a rotary stage unit 45 including a rotary stage 41 that supports the disk 11 and a spindle motor 44 that has a motor shaft provided so as to coincide with the central axis 42 of the stage 41, and a rotary stage. A shaft 46 that penetrates a part of the unit 45 and extends in one radial direction Y of the rotary stage 41 and a linear moving means 49 for moving the rotary stage unit 45 along the shaft 46 are provided. A part of the rotary stage unit 45 is screwed with a precise threaded rod 47 arranged in parallel with the shaft 46 so that the rod 47 is rotated forward and backward by a pulse motor 48. The rod 47 and the pulse motor 48 constitute a linear moving means 49 of the rotary stage unit 45. Further, a means (not shown) for generating a reference clock signal according to the rotation of the rotary stage 41 is provided.

  Further, the electron beam drawing apparatus 40 includes an electron gun 23 that emits an electron beam EB, deflection means 21 and 22 that deflect the electron beam EB in the Y direction (disk radial direction) and the X direction (circumferential direction) perpendicular to the Y direction. The aperture 25 and the blanking 26 (deflector) are provided as blanking means for turning on / off the irradiation of the electron beam EB. The electron beam EB emitted from the electron gun 23 is deflected by the deflecting means 21 and 22 and illustrated. Irradiated onto the disk 11 through a lens or the like that does not. At the time of pattern drawing, the deflecting means 21 and 22 are controlled to cause the electron beam EB to vibrate minutely in the circumferential direction X of the disk 11 with a constant amplitude.

  The aperture 25 in the blanking means is provided with a through-hole through which the electron beam EB passes at the center, and the blanking 26 does not deflect the electron beam EB at the time of an on signal when the on / off signal is input. When the signal is off, the electron beam EB is deflected and blocked by the aperture 25 without passing through the aperture 25 so as not to irradiate the electron beam EB. To do. When the elements 13 and 14 are being drawn, an ON signal is input to irradiate the electron beam EB, and when moving between the elements 13 and 14, an OFF signal is input to interrupt the electron beam EB and exposure is performed. It is controlled not to perform. Using this blanking means, the first and second elements 13 and 14 are drawn as described above.

  Driving the spindle motor 44, that is, the rotational speed of the rotary stage 41, driving the pulse motor 48, that is, linear movement by the linear moving means 49, modulation of the electron beam EB, control of the deflecting means 21 and 22, and on / off control of the blanking 26. Are performed based on the reference clock signal by the drawing data signal sent from the controller 50 as the control means.

  The disk 11 installed on the rotary stage 41 is made of, for example, silicon, glass or quartz, and a positive electron beam drawing resist is coated on the surface thereof in advance.

  It is desirable to adjust the output of the electron beam EB and the beam diameter in consideration of the shape of each element 13 and the sensitivity of the electron beam drawing resist.

The top view (a) which shows the transfer pattern of the master carrier for magnetic transfer drawn by the electron beam drawing method of this invention, the enlarged schematic diagram (b) which shows the drawing system by 1st Embodiment of the element which comprises a transfer pattern, and An enlarged schematic diagram (c) showing a drawing method according to a reference example not included in the present invention of elements constituting a transfer pattern FIG. 1B is an enlarged schematic diagram showing a servo pattern drawing order according to the first embodiment. FIG. 1C is an enlarged schematic diagram showing the servo pattern drawing order according to the reference example . Side view (a) and top view (b) of main parts of an electron beam drawing apparatus according to an embodiment for carrying out the electron beam drawing method of the present invention.

Explanation of symbols

11 discs
12 patterns
13 First element
14 Second element D Deflection feed
EB electron beam T track X circumferential direction Y disk radial direction
21, 22 Deflection means
23 electron gun
25 Aperture
26 Blanking (Blanking means)
40 Electron beam lithography system
41 Rotating stage
44 Spindle motor
45 Rotating stage unit
49 Linear movement means
50 controller

Claims (3)

The transfer pattern of the master carrier for magnetic transfer is scanned with an electron beam irradiated from an electron beam drawing device while rotating the rotary stage on a disk placed on a rotary stage coated with a resist and movable in the radial direction. An electron beam drawing method for drawing an element constituting a transfer pattern by
The transfer pattern has a first element arranged in a track width and a second element arranged in a half of the track width in a transfer region of each sector of a circumferential track,
The electron beam drawing apparatus includes a deflection unit that deflects an electron beam to be irradiated in a radial direction of the disk, and a blanking unit that blocks irradiation of the electron beam except for a drawing portion.
While the disk is rotated in one direction, the electron beam is deflected in the radial direction by one track by the deflecting means, and the first and second elements are drawn by one track by one rotation of the disk. And
The drawing of the first element is performed by irradiating an electron beam for a deflection corresponding to the track width, while the drawing of the second element is for a half track that is not drawn out of the deflection corresponding to the track width. The electron beam writing method is characterized in that the electron beam irradiation is performed by blocking the electron beam irradiation by the blanking means and irradiating the electron beam for the remaining half track deflection. A circumferential drawing the length of the element, electron beam lithography according to the electron beam to claim 1, characterized in that defined by the amplitude reciprocally vibrate at high speed to substantially perpendicular to the circumferential direction and a radial direction of said disk Method. The transfer pattern, electron beam writing method of claim 1 or 2, characterized in that a servo pattern including a burst portion.

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