JP2008302519A - Nanoimprint apparatus and nanoimprint method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nanoimprint apparatus capable of shortening a molding tact time. <P>SOLUTION: The nanoimprint apparatus includes: a mold holder; a rubber sheet; a mold having a minute pattern on the surface thereof; a substrate holder; a first heat source metallic die; and a second heat source metallic die. The rubber sheet, the mold, a thermoplastic substrate and the substrate holder are layered in this order on the mold holder so that the minute pattern of the mold is opposed to the thermoplastic substrate to obtain a laminate. The laminate is held between the first heat source metallic die and the second heat source metallic die so that the first heat source metallic die is opposed to the side of the substrate holder and the second heat source metallic die is opposed to the side of the mold holder. The held laminate is hot-pressed to transfer the minute pattern of the mold to the thermoplastic substrate. When the held laminate is hot-pressed, the thermoplastic substrate is heated by the first heat source metallic die so that the temperature of the thermoplastic substrate becomes higher than the glass transition temperature thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nanoimprint apparatus and a nanoimprint method.

  In recent years, with the increase in the amount of information, the demand for large-capacity high-recording density media such as hard disks has increased. In addition, high capacity and high recording density media are also required for reliability and cost reduction. Optical discs have the reliability to meet these expectations and are low in cost, so the demand area is wide.

  However, since the recording capacity of one optical disk is smaller than that of a hard disk or the like, further increase in recording density can be said to be a current problem. High-density optical media using a blue laser in which the spot diameter of a laser used for recording and reproduction is narrowed, such as HDDVD (registered trademark) and Bluray Disk (registered trademark), have appeared. These can increase the density of the optical disk by making the land prepits (groove shape) on the pattern surface of the disk finer than the current DVD in forming the disk. Very strict.

  Thus, a flexible optical disk in which the disk substrate itself is thinned has been widely developed to further increase the recording density by utilizing the conventional technology. Even if the disk thickness is reduced, if the conventional recording capacity can be reproduced as it is, a large capacity can be realized even if a large number of sheets are filled, although the size is the same.

  Mainly, injection molding is used for molding the disk substrate. However, when the substrate thickness is 0.3 mm or less, the flatness of the substrate cannot be maintained, and the molding is very difficult. Therefore, by sandwiching a thermoplastic substrate such as polycarbonate with a thickness of 0.3 mm or less between a Ni mold having a fine pattern on the surface and a substrate holding plate, and heating and pressing, the Ni mold fine pattern is applied to the substrate. Substrate molding with a thickness of 0.3 mm or less became possible by using nanoimprint technology for thermal transfer. An example of such a nanoimprint technique is described in Patent Document 1.

  Further, in order to uniformly transfer a large area such as an optical disk having a diameter of 120 mm, a rubber sheet for uniformly distributing a load on the back side of the Ni mold is often used.

JP 2003-1705 A

  In the process of thermally transferring a fine pattern to a thin plastic substrate with a thermal nanoimprinting device, the rubber sheet for uniformly dispersing the load used on the back side of the Ni mold is generally low in thermal conductivity. There is a problem that it takes time for heat to be transferred to the plastic substrate and the molding tact time becomes long.

  In view of the foregoing, it is an object of the present invention to provide a nanoimprint apparatus and method that can shorten the forming tact.

  The present inventors are able to perform heating necessary for nanoimprinting more quickly by heating from the thermoplastic substrate side rather than from the mold side having a rubber sheet having low thermal conductivity as in the past. I came up with it.

  The nanoimprint apparatus of the present invention includes a mold holder, a rubber sheet, a mold having a fine pattern on the surface, a substrate holder, a first heat source mold, and a second heat source mold, the mold holder, A rubber sheet, the mold, a thermoplastic substrate, and the substrate holder are laminated in this order so that the fine pattern of the mold faces the thermoplastic substrate from the substrate holder side. A nanoimprint apparatus for transferring a fine pattern of the mold to the thermoplastic substrate by sandwiching the first heat source mold from the mold holder with the second heat source mold and performing heat press, and during the heat press, The first heat source mold is formed from the glass point transfer temperature of the thermoplastic substrate. Wherein the heating to the temperature. By shortening the heating time, the molding tact can be shortened.

  At the time of hot pressing, the second heat source mold may generate heat at a temperature lower than that of the first heat source mold for heat retention.

  At the time of hot pressing, preferably, the first heat source mold heats the thermoplastic substrate to a temperature of 10 ° C. or more from its glass point transfer temperature.

  The nanoimprint method of the present invention includes a mold holder, a rubber sheet, the mold having a fine pattern on the surface, the thermoplastic substrate, and a substrate holder in this order, and the fine pattern of the mold is the thermoplastic. A step of laminating the plastic substrate to face each other, the laminated mold holder, the rubber sheet, the mold, the thermoplastic substrate, and the substrate holder from the substrate holder side to the first heat source metal A mold, sandwiched by a second heat source mold from the mold holder side, the first heat source mold heating and pressing the thermoplastic substrate above its glass point transfer temperature, and after the heating press, A step of cooling the thermoplastic substrate to a predetermined temperature, and the thermoplastic plastic After the plate is cooled to a predetermined temperature, characterized in that it comprises a step of removing the thermoplastic substrate from the mold.

  According to the present invention, the molding tact time can be shortened in the nanoimprint technology.

An embodiment of a nanoimprint apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of the configuration of the nanoimprint apparatus of the present invention. First, as shown in FIG. 1 (a), a rubber sheet 2 having a disk shape and a center hole is stacked on a mold holder 1 having a center pin, and a fine pattern is formed on the surface thereof. The mold 3 having a center hole is overlapped so that the fine pattern is on top, the edge portion is pressed with the mold presser 4, and the center hole is formed in a disc shape with a thickness of 0.3 mm or less. A thermoplastic substrate 5 is stacked, and a disk-shaped substrate holder 6 having a center hole is stacked thereon.

  As the thermoplastic substrate 5, methyl methacrylate resin (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like is used. When using as an optical disk, it is desirable to use PC from the birefringence characteristic.

The rubber sheet 2 is for uniformly dispersing the load, and generally a silicone rubber sheet or a fluorine rubber sheet is used. The thickness is preferably 1 to 3 mm.
The mold 3 is preferably made of Ni, NiP or the like.

  The substrate holder 6 is made of a metal having high thermal conductivity. When flatness is required, SUS metal, nickel phosphorus, aluminum alloy or the like is usually used. Further, beryllium copper may be used to increase thermal conductivity. Preferably, the thermal conductivity is 15 to 400 (W / m · K). The side facing the thermoplastic substrate 5 is preferably mirror-finished with a surface roughness Ra = 10 nm or less.

  As shown in FIG. 1B, a laminated body in which the mold holder 1, the rubber sheet 2, the mold 3, the mold presser 4, the thermoplastic substrate 5 and the substrate holder 6 are stacked as shown in FIG. The first heat source mold 7 and the second heat source mold 8 are sandwiched in the stacking direction. The first heat source mold 7 and the second heat source mold 8 each have a built-in heater, and nanoimprinting is performed by applying a weight while heating the laminated body sandwiched therebetween.

  In order to transfer the fine pattern of the mold 3 to the thermoplastic substrate 5 by nanoimprinting, it is necessary to heat the surface where the thermoplastic substrate 5 and the mold 3 are in contact with each other to the glass transition temperature Tg or more of the thermoplastic substrate 5. , And preferably heated to about Tg + 10 ° C. In the nanoimprint apparatus of the present invention, the thermoplastic substrate 5 and the mold 3 are heated mainly from the thermoplastic substrate 5 side, that is, heated by the first heat source mold 8.

  The thermoplastic substrate 5 and the mold 3 are quickly heated to Tg or higher because the rubber sheet 2 having a low thermal conductivity is heated from the side of the thermoplastic substrate 5 having the substrate holder 6 having a high thermal conductivity instead of the side of the mold 3 having the low thermal conductivity. It is possible to shorten the nanoimprint tact time.

  In the nanoimprint, since it is desired to apply heat only during the application of a load, the first heat source mold 7 is usually heated so that the thermoplastic substrate 5 and the mold 3 are Tg or less or Tg + 10 ° C. or less before and after applying the load. . Only during the application of weight, the first heat source mold 7 is heated so that the thermoplastic substrate 5 and the mold 3 have a temperature of about Tg + 10 ° C.

  At this time, heat can be prevented from escaping from the mold 3 side by keeping the second heat source mold 8 at a temperature that is the same as or lower than that of the first heat source mold 7. It becomes possible to heat the thermoplastic substrate 5 and the mold 3 faster. However, heating from the mold 3 side also increases the time required for cooling, so it is desirable not to set the temperature too high.

  For example, when the material of the thermoplastic substrate 5 is polycarbonate, since Tg is about 150 ° C., it is necessary to heat it to about 160 ° C. or more. Therefore, if the first heat source mold 7 is set to 200 ° C. and the second heat source mold is set to 150 ° C., the thermoplastic substrate 5 and the mold 3 can be heated to Tg (150 ° C.) + 10 ° C. or more. .

  After the laminate is heated and pressed by the first heat source mold 7 and the second heat source mold 8, the heat source mold 7 and the second heat source mold 8 are removed, and as shown in FIG. If the substrate 5 is peeled from the mold 3, the thermoplastic substrate 5 to which the fine pattern of the mold 3 is transferred is obtained.

  As described above, when the thermoplastic substrate 5 is taken out after the heating press, it is necessary to remove the first heat source mold 7 and the second heat source mold 8 and cool the laminated body, but the thermal conductivity is low even during the cooling. Since there is the rubber sheet 2, the heat radiation on the mold 3 side is worse than that on the thermoplastic substrate 5 side. Therefore, the nanoimprint apparatus of the present invention in which the heating temperature from the mold 3 side is lower than the heating temperature on the thermoplastic substrate 5 side can shorten the cooling time compared to the conventional nanoimprint apparatus that heats from the mold 3 side. There is an effect.

<Example>
Using the nanoimprint apparatus of the present invention as described above, the time for heating and cooling when actually transferring the fine pattern of the mold to the thermoplastic substrate was measured. The configuration of the nanoimprint apparatus was the same as that shown in FIG. A polycarbonate sheet substrate having a thickness of 0.1 mm was used as the thermoplastic substrate. A silicon rubber sheet was used as the rubber sheet. As the substrate holder, a stainless steel mirror plate was used.

  As an example of the present invention, the temperature at the time of the heat press of the first heat source mold on the thermoplastic substrate side is set to 200 ° C., and the temperature at the time of the heat press of the second heat source mold on the mold side is set to 150 ° C. did.

  As a comparative example, the temperature at the time of heating the second heat source mold on the mold side was set to 200 ° C., and heating was performed only from the mold side as in the past.

  In both the examples and comparative examples, after heat pressing, cooling was performed, and when the temperature reached 100 ° C., the thermoplastic substrate was peeled from the mold.

  Fig.2 (a) is a graph which shows the temperature change of the thermoplastic sheet at the time of the hot press of an Example and a comparative example, FIG.2 (b) is a graph which shows the temperature change at the time of cooling. The vertical axis represents the temperature [° C.] of the thermoplastic substrate, and the horizontal axis represents time [min]. Examples are indicated by solid lines, and comparative examples are indicated by dotted lines.

  As can be seen from these graphs, both the heating and the cooling time, the example reached the predetermined temperature earlier than the comparative example, and the example could finish the nanoimprint process about 2 minutes earlier than the comparative example. . From this measurement result, it was demonstrated that the nanoimprint apparatus of the present invention can realize a shorter tact time than the conventional nanoimprint apparatus.

  The present invention is applicable to a nanoimprint apparatus.

(A), (b) and (c) are the schematic which shows an example of a structure of the nanoimprint apparatus of this invention. It is a graph which shows the result of the heating experiment of the thermoplastic sheet in the Example and comparative example of this invention, (a) shows the result at the time of heating, (b) shows the result at the time of cooling.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold holder 2 Rubber sheet 3 Mold 4 Mold presser 5 Thermoplastic substrate 6 Substrate holder 7 First heat source mold 8 Second heat source mold

Claims (6)

A mold holder, a rubber sheet, a mold having a fine pattern on the surface, a substrate holder, a first heat source mold, and a second heat source mold;
The mold holder, the rubber sheet, the mold, the thermoplastic substrate, and the substrate holder are laminated in this order so that the fine pattern of the mold faces the thermoplastic substrate. The nanoimprinting apparatus transfers the fine pattern of the mold to the thermoplastic substrate by sandwiching and pressing the first heat source mold from the substrate holder side and the second heat source mold from the mold holder side. And
The nanoimprint apparatus, wherein the first heat source mold heats the thermoplastic substrate to a temperature higher than a glass point transfer temperature during the heating press.   The nanoimprint apparatus according to claim 1, wherein the second heat source mold generates heat to a temperature lower than that of the first heat source mold.   3. The nanoimprint apparatus according to claim 1, wherein the first heat source mold heats the thermoplastic substrate to a temperature of 10 ° C. or more from its glass point transfer temperature during hot pressing. A nanoimprint method for transferring a fine pattern of a mold to a thermoplastic substrate,
A mold holder, a rubber sheet, the mold having a fine pattern on the surface, the thermoplastic substrate, and a substrate holder are laminated in this order so that the fine pattern of the mold faces the thermoplastic substrate. And a process of
The mold holder, the rubber sheet, the mold, the thermoplastic substrate, and the substrate holder that are laminated are a first heat source mold from the substrate holder side and a second heat source metal from the mold holder side. Sandwiching by a mold, the first heat source mold heating and pressing the thermoplastic substrate above its glass point transfer temperature; and
After the heating press, cooling the thermoplastic substrate to a predetermined temperature;
And a step of peeling the thermoplastic substrate from the mold after the thermoplastic substrate is cooled to a predetermined temperature.   5. The nanoimprint method according to claim 4, wherein, in the heating and pressing step, the second heat source mold generates heat at a lower temperature than the first heat source mold.   6. The nanoimprint method according to claim 4, wherein, in the heating and pressing step, the first heat source mold is heated to a temperature of 10 ° C. or more from a glass point transition temperature of the thermoplastic substrate.

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