JP2006018867A - Electron beam lithography method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely and speedily draw a fine pattern including a first element having a track width and a second element sifted by a half pitch, on the overall surface of a disk. <P>SOLUTION: In the method for drawing the first element 13 disposed on the track width of a transfer pattern and the second element 14 sifted by the half track so as to be disposed across the adjacent track, by scanning the disk 11 on which a resist is applied with the electron beam EB, for the transfer pattern of the master carrier for the magnetic transferring, the deflection for shifting the electron beam in one track of the disk with respect to the radial direction is performed, while rotating the disk in one direction so that the drawing of the first element 13 on the track is performed. The defection of the electron beam with respect to the radial direction is simultaneously sifted by the half track so that the drawing of the second element 14 across the adjacent track is performed at a time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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.

  In the magnetic transfer master carrier, fine patterns are drawn by rotating a resist-coated disc and irradiating a laser beam modulated according to the information to be transferred, as in the case of the optical disc stamper. It is generally considered to do.

  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 as a transfer pattern in each sector of a circumferential track 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 are 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 is arranged across an adjacent track with a half-pitch deviation, and is coated on a disc. It is necessary to write the elements of the transfer pattern one by one on the resist with an electron beam 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 that is shifted by a half pitch from the 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 (sector number) 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 second element shifted by a half pitch together with a first element having a track width on the entire surface of a disk with high accuracy and at high speed. It is intended to provide.

In the electron beam drawing method of the present invention, a transfer pattern of a master carrier for magnetic transfer is transferred onto a disk placed on a rotary stage coated with a resist and movable in the radial direction, while rotating the rotary stage, An electron beam drawing method for drawing elements constituting a transfer pattern by scanning,
The transfer pattern includes: a first element arranged in a track width in a transfer region of each sector of a circumferential track; and a second element arranged over an adjacent track with a half track deviation from the track width. Have
While the disk is rotated in one direction, the electron beam is deflected in a radial direction within one track of the disk, and scanning is performed so as to fill the shape of the first element of the track. At the same time that the element is drawn, the radial deflection of the electron beam is shifted by half a track with respect to the drawing of the first element, and scanning is performed so as to fill the shape of the second element across adjacent tracks. Thus, the second element is drawn at once.

  At this time, 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.

  When drawing of the elements of one or more tracks is completed, it is preferable to shift the relative position of the disk and the electron beam in the rotation direction of the disk and draw the transfer pattern on the entire surface 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, and deflecting the electron beam to reciprocate at a high speed in the circumferential direction and to send it in the radial direction. It comprises a deflection scanning means, a means for sending a drawing data signal for scanning the electron beam corresponding to each element of the pattern, and a control means for controlling these operations in linkage.

  In the electron beam writing method of the present invention, the deflection of sending the electron beam in the radial direction is performed while rotating the disk in one direction, the first element having the track width is drawn, and at the same time, the deflection of the electron beam in the radial direction is performed. By drawing the second element across the adjacent tracks by shifting a half track at a time, the first element and the second element shifted by a half pitch can be drawn at a time. 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 pattern of a magnetic transfer master carrier drawn by the electron beam drawing method of the present invention, and FIG. 1B is an enlarged schematic view showing a basic drawing form of elements constituting the pattern. 2 is an enlarged schematic diagram showing the drawing order of servo patterns. FIG. 3 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 2, the concentric track T has a first element 13 and a second element that correspond to the information to be transferred. Elements 14 (see FIG. 2) are arranged and constituted by a collection of them. The shape of the first element 13 in each track T is a rectangular shape with a width W corresponding to the track width and a length (bit length) L, and the second element 14 has a similar rectangular shape. The first element 13 is formed so as to extend over adjacent tracks with a half track shift. 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, as shown in FIG. 2, the preamble (synchronization signal) and the gray code (track number identification signal) are transferred by the first element 13 recorded to the full width of the track. A burst signal for head positioning is recorded by the second element 14 which is shifted in pitch.

  Drawing of the elements 13 and 14 of the pattern 12 is performed, for example, on the outer periphery of the track on the inner peripheral side while the disk 11 having a resist coated on the surface is placed on a rotating stage 41 (see FIG. 3) described below and rotated. The resist is 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.

  As shown in FIG. 1B, the basic mode of the electron beam writing method according to the present invention is that the disk 11 is rotated in one direction A while the disk 11 is rotated in the circumferential direction X perpendicular to the radial direction Y of the disk 11. When viewed visually, the second element 14 that is shifted in the radial direction by a half track is continuously formed together with the rectangular first element 13 at a predetermined phase position of a concentric track T (track width: W) extending linearly. Then, the drawing is performed by scanning with the electron beam EB having a small diameter so as to fill the shape at once.

  In the above scanning, the electron beam EB having a beam diameter smaller than the minimum width of the elements 13 and 14 is vibrated by reciprocating at a constant amplitude L in the circumferential direction X substantially orthogonal to the radial direction Y at high speed. By deflecting the electron beam EB to the feed D and performing the feed D, the electron beam EB scans so that the shape of the first element 13 is filled with a triangular wave-like locus, and the center of the feed D is half the Y-direction deflection voltage. Similarly, the electron beam EB is scanned so as to be filled with a triangular wave trajectory, and the elements 13 and 14 are sequentially drawn. After drawing one track T once, move to the next track T and draw in the same way, and draw a desired fine pattern 12 in the entire area of the disk 11 That.

  FIG. 2 shows the drawing order of the elements 13 and 14 of a plurality of tracks. First, the T1 track is drawn with the deflection center in the Y direction aligned with the center of the T1 track, and the first and second elements 13 and 14 are drawn in the order of 1 · 1 to 1 · 6. That is, in accordance with the rotation direction A, after the drawing of the first first element 13 at the head of the sector 1 · 1, 1 · 2 is performed, the second second element 14 continues by shifting the deflection center in the Y direction by a half track. Drawings 1, 3, 1, and 4 are performed, the deflection center in the Y direction is returned to the center of the T 1 track, and the subsequent two first elements 13 are drawn 1, 5, 1, and 6.

  In the next rotation, the Y-direction deflection center is aligned with the center of the T2 track, and the first element 13 and the second element 14 are similarly drawn in the order of 2 · 1 to 2 · 6. At the next rotation, the deflection center 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 in the order of 3 · 1 to 3 · 6.

  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.

  The second element 14 corresponding to the half pitch of the innermost track or the outermost track is drawn by cutting the electron beam EB for the half track using an aperture 25 and blanking 26, which will be described later, and drawing only half. Can be done.

  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. 3 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. And an aperture 25 and a blanking 26 (deflector) for turning on / off the irradiation of the electron beam EB. The electron beam EB emitted from the electron gun 23 is applied to the deflecting means 21 and 22 and a lens (not shown). After that, the light is irradiated onto the disk 11. 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 has a through-hole through which the electron beam EB passes in the center, and the blanking 26 has a through-hole in the aperture 25 without deflecting the electron beam EB when the on-signal is input in response to the input of the on / off signal. On the other hand, at the time of an off signal, the electron beam EB is deflected and blocked by the aperture 25 without passing through the aperture 25, so that the electron beam EB is not irradiated. 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.

  The drive of the spindle motor 44, that is, the rotational speed of the rotary stage 41, the drive of the pulse motor 48, that is, the linear movement by the linear movement means 49, the modulation of the electron beam EB, the control of the deflection means 21 and 22, the control of the blanking 26, etc. This is performed based on the reference clock signal by the drawing data signal sent from the controller 50 as means.

  When the concentric pattern is drawn, the rotary stage 41 is moved by a predetermined distance every time the rotary stage 41 is rotated, and when the spiral pattern is drawn, the rotary stage 41 is linearly moved almost continuously.

  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.

  At the time of drawing by the drawing device 40, the disk 11 is rotated in the A direction, and the Y-direction and X-direction deflecting means 21 and 22 are controlled in synchronization with each other by a periodic function signal such as a triangular wave to control the electron beam EB. By periodically oscillating with a constant amplitude in a predetermined direction, the electron beam EB is scanned in the circumferential direction X of the element 13 a plurality of times as a result, the shape is drawn, and the pattern 12 is drawn by repeating this. I do. In particular, when the second element 14 is drawn, the driving voltage of the Y-direction deflecting means 21 is applied by being overlapped by a half track, and the fluctuation center of the width W in the Y direction is shifted to the outer peripheral side by a half track. By performing the control, both the elements 13 and 14 are drawn continuously by one rotation of the disk.

  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 figure which shows the pattern of the master carrier for magnetic transfer drawn by the electron beam drawing method of this invention, and the enlarged schematic diagram which shows the basic drawing form of the element which comprises a pattern Enlarged schematic diagram showing servo pattern drawing order FIG. 1 is a side view and a top view of an essential part 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 2nd element D Deflection feed
EB electron beam T track X circumferential direction Y disk radial direction
21, 22 Deflection means
23 electron gun
40 Electron beam lithography system
41 Rotating stage
44 Spindle motor
45 Rotating stage unit
49 Linear movement means
50 controller

Claims (4)

The transfer pattern of the magnetic transfer master carrier is constituted by scanning the electron beam 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,
The transfer pattern includes: a first element arranged in a track width in a transfer region of each sector of a circumferential track; and a second element arranged over an adjacent track with a half track deviation from the track width. Have
While the disk is rotated in one direction, the electron beam is deflected in a radial direction within one track of the disk, and scanning is performed so as to fill the shape of the first element of the track. At the same time that the element is drawn, the radial deflection of the electron beam is shifted by half a track with respect to the drawing of the first element, and scanning is performed so as to fill the shape of the second element across adjacent tracks. An electron beam writing method, wherein the second element is drawn at a time.   2. The electron beam drawing according to claim 1, wherein 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. Method.   3. When the drawing of one or more track elements is completed, the transfer pattern is drawn on the entire surface of the disk by shifting the relative position of the disk and the electron beam in the rotation direction of the disk. The electron beam drawing method described in 1.   The electron beam drawing method according to claim 1, wherein the transfer pattern is a servo pattern including a burst portion.

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