JP2009241582A - Imprinting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imprinting method with high utility by solving a problem in LADI method. <P>SOLUTION: The imprint method comprises a step for irradiating an electromagnetic wave in a state that a transcribed face of a transcribed body is contacted to an uneven face of a mold with the uneven face to soften the transcribed face by transcribing the uneven face shape of the uneven face the transcribed face. The method includes an exothermic layer forming step which forms an exothermic layer that generates heat by absorbing the electromagnetic wave, and a softening step for softening the transcribed face by making the exothermic layer generate heat by irradiating an electromagnetic wave through the mold which is formed of a material that transmits the electromagnetic wave or the transcribed body, and softens the transcribed face. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imprint method for irradiating a mold having a fine uneven surface with electromagnetic waves and transferring the fine uneven shape to a transfer target.

  In recent years, research and development of devices having fine structures processed using nano-order processing techniques have been actively conducted. Among these, the nanoimprint technique is a method of transferring a mold pattern onto a substrate by pressing a mold having a nano-size pattern onto a substrate that is a transfer target. This method is high in productivity and low in cost.

As the nanoimprinting method, the thermal nanoimprinting method and the optical nanoimprinting method are mainly used, but as a method aiming at higher resolution and higher speed processing, a nanoimprinting (LADI) method using laser light has been proposed. In the LADI method, a mold in which a predetermined pattern is formed on a molten crystal is brought into contact with a silicon substrate and pressed, and this state is maintained and XeCl excimer laser pulses are irradiated. At that time, the surface of the silicon substrate is melted and liquefied, and as a result, a predetermined pattern is imprinted on the silicon substrate. Furthermore, it has been suggested that a semiconductor material, metal or alloy, polymer, or ceramic can be formed on the surface of the silicon substrate (see, for example, Non-Patent Document 1 and Patent Document 1).
Stephan Y. Chou et. al. , Appl. Phys. Lett, Vol. 67, Issue 21, pp. 3114-3116 (1995) JP-T-2005-521243

  However, the conventionally proposed LADI method has the following problems. First, when a substrate made of a material that transmits laser light having a predetermined wavelength to be irradiated is used, most of the laser light is transmitted through the substrate, and heat necessary for melting or liquefying the substrate surface. Since imprinting does not occur, imprint cannot be realized. That is, there is a problem that a substrate made of a material that transmits the irradiated laser beam cannot be used.

  As described above, Patent Document 1 and the like suggest that it is also possible to form a semiconductor material, metal or alloy, polymer, or ceramic on the substrate surface. There is no indication of the purpose of providing or a specific solution to the first problem.

  Secondly, when a mold made of a material that does not transmit laser light having a predetermined wavelength to be irradiated is used, the laser light is absorbed by the mold and the substrate surface cannot be melted and liquefied. was there. That is, there is a problem that only a mold made of a material that transmits the irradiated laser beam can be used.

  In addition, since excimer lasers are gas lasers, they must be stable for a long period of time and require maintenance, and the laser beam is incident on the laser beam with the specified wavelength. Therefore, there is a problem that the degree of freedom in device design is low.

  The present invention has been made in view of the above, and an object of the present invention is to solve the problems of the LADI method and provide a more practical imprint method.

  In order to achieve the above object, the first invention is configured to irradiate an electromagnetic wave in a state where the uneven surface of the mold having an uneven surface and the transferred surface of the transferred body are brought into contact with each other. A method of imprinting to soften and transferring the concavo-convex shape of the concavo-convex surface to the transfer surface, the heat generation layer forming step of forming a heat generation layer that absorbs the electromagnetic waves and generates heat on the transfer surface; A softening step of softening the transferred surface by irradiating the heat generating layer with the electromagnetic wave via the mold or the transferred object, one of which is made of a material that transmits the electromagnetic wave, and generating heat in the heated layer; It is characterized by having.

  In a second aspect of the invention, the two uneven surfaces of the mold having two uneven surfaces and the two transferred surfaces of the two transferred objects are brought into contact with each other to irradiate electromagnetic waves to the two transferred objects. An imprinting method for softening a transfer surface and transferring the concavo-convex shape of the two concavo-convex surfaces to the two transferred surfaces, wherein a heat generating layer that absorbs the electromagnetic waves and generates heat on the two transferred surfaces The heat generating layer forming step to be formed, and the heat generating layer is irradiated with the electromagnetic wave through the two transferred objects composed of the material that transmits the electromagnetic wave, and the heat generating layer is heated to generate the two transferred objects. And a softening step for softening the surface.

  According to the present invention, it is possible to solve the problems of the LADI method and to provide a more practical imprint method.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

<First Embodiment>
The imprint method according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 7 are schematic views illustrating an imprint method according to the first embodiment of the invention. 1 to 7, reference numeral 11 denotes an object to be transferred, 12 a heat generating layer, 13 a mold, and 14 an electromagnetic wave. Reference numeral 11a denotes a transfer surface of the transfer body 11, and 13a denotes an uneven surface of the mold 13.

First, in the process shown in FIG. 1, a transfer object 11 is prepared, and a heat generation layer 12 is formed on a transfer surface 11 a of the transfer object 11 (heat generation layer forming process). Examples of the material of the transfer target 11 include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, silicon resin, fluorine resin, ABS resin, and urethane resin. Crystals of resins typified by SiO2, oxides typified by SiO ₂ , Al ₂ O ₃ , nitrides typified by SiN, AlN, and carbides typified by SiC and GC (glassy carbon) Alternatively, a ceramic material and a material used as a so-called substrate such as Si can be used. In the process shown in FIG. 4 to be described later, the heat generating layer 12 absorbs the electromagnetic wave 14 irradiated through the transfer target 11 or the mold 13 made of a material that transmits the electromagnetic wave 14, and This is a layer composed of a heat generating material that generates a quantity of heat that can soften the transfer surface 11a.

  The amount of heat generated in the heat generating layer 12 is adjusted by the amount of absorption of the material constituting the heat generating layer 12 with respect to the electromagnetic wave 14, the thermal conductivity, and the film thickness of the heat generating layer 12. FIG. 8 is a diagram schematically illustrating the relationship between the amount of absorption with respect to the electromagnetic wave 14, the thermal conductivity, the thickness of the heat generating layer 12, and the amount of heat generated in the heat generating layer 12. In FIG. 8, the area of the shaded area surrounded by the triangle is the amount of heat generated in the heat generating layer 12, and the imbalance between the amount of absorption with respect to the electromagnetic wave 14, the thermal conductivity, and the film thickness of the heat generating layer 12 shown in FIG. By optimizing the transfer target 11, a good imprint can be realized.

  For example, a material having a predetermined absorption amount and a predetermined thermal conductivity with respect to the electromagnetic wave 14 is selected, and the heat generation layer 12 generates a necessary amount of heat in consideration of the predetermined absorption amount and the predetermined thermal conductivity. The optimum film thickness of the heat generating layer 12 is determined. The amount of absorption and the thermal conductivity are preferably in the range of about 50 to 100% and about 20 to 400 W / m / k, for example.

  The material constituting the heat generating layer 12 is preferably a material that has good releasability from the transfer target 11 and that generates the same heat upon multiple irradiations of the electromagnetic wave 14. Specifically, Si, Ge as a semiconductor, Sn, Sb, Bi as semimetals, Cu, Au, Pt, Pd as noble metals, Zn, Ni, Co, Cr as transition metals, or alloys thereof In addition, a carbide represented by SiC, TiC or the like, a ceramic material such as an oxygen-deficient oxide represented by SiOx or GeOx, or a composite thereof is preferable. Moreover, it is more preferable that the material constituting the heat generating layer 12 includes a phase change material. This is because the phase change material has a large amount of absorption and heat generation with respect to the electromagnetic wave 14, and therefore the heat generation layer 12 can reduce the optimum film thickness for generating the necessary amount of heat and can improve productivity. .

  The phase change material can be appropriately selected from those used as the material of the recording layer of the rewritable optical recording medium. For example, Sb, Ge, Ga, In, Zn, Mn, Sn, Ag, Mg It is preferable to use a material containing one or more elements selected from Ca, Ag, Bi, Se, and Te. As these phase change materials, desired materials can be used from the viewpoint of thermal characteristics and optical characteristics, but GeSbTe alloy, AgInSbTe alloy, AgInSbTeGe alloy, GaSbSnGe alloy, GeSbSnMn alloy, GeInSbTe alloy, GeSbSnTe alloy and the like are preferable.

  In addition, the heat generating layer 12 may have not only a single layer configuration but also a multilayer configuration in which a plurality of layers are stacked. By adopting a multilayer structure, it is possible to adjust not only the amount of heat generated but also the maintenance of temperature and the cooling rate, and better imprinting can be realized.

Next, in a process shown in FIG. 2, a mold 13 having an uneven surface 13a is manufactured (mold manufacturing process). The uneven surface 13a is, for example, a surface having a nanoscale uneven pattern. Examples of the material of the mold 13 include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, silicon resin, fluorine resin, ABS resin, and urethane resin. Resins, oxides typified by SiO ₂ , Al ₂ O ₃ , nitrides typified by SiN, AlN, etc., crystals or ceramics such as carbides typified by SiC or GC (glassy carbon) Materials, and metal materials such as Ni and Ta, which are generally used in the nanoimprint method, can be used. The uneven surface 13a of the mold 13 can be formed by, for example, FIB (Focused Ion Beam) processing. As is well known, FIB (Focused Ion Beam) processing is a processing method that uses a finely focused Ga (gallium) ion beam, and a complicated shape can be produced with submicron level accuracy.

  Next, in the step shown in FIG. 3, the heat generating layer 12 formed on the transfer surface 11 a of the transfer body 11 and the convex portion of the uneven surface 13 a of the mold 13 are brought into contact with each other. The contact is performed by strongly pressing the transfer body 11 and the mold 13 with external pressure. As a specific method of contact, a method of pressing with a mechanical force using a dedicated pressing machine may be used, but the space between the heat generating layer 12 and the uneven surface 13a of the mold 13 is evacuated, and pressure bonding is performed by an external air pressure. A method using vacuum adsorption is preferable (vacuum adsorption step).

  Vacuum adsorption can be realized using a general-purpose apparatus, and it is easy to maintain the adsorption state. Further, even when the mechanical strength of the transfer target 11 or the mold 13 is not strong, a minimum necessary pressure can be obtained so as not to destroy the transfer target 11 or the mold 13. By using vacuum suction, a good imprint can be realized. For example, the vacuum suction is realized by an existing vacuum bonding apparatus used for bonding two substrates constituting a DVD-ROM, which is a well-known optical recording medium, in a vacuum in which there is no gas that causes bubbles. can do.

  Next, in the process shown in FIG. 4, the heat generating layer 12 is irradiated with the electromagnetic wave 14 through the transferred object 11 or the mold 13 made of a material that transmits the electromagnetic wave 14, and the heat generating layer 12 generates heat to be transferred. The transferred surface 11a of the body 11 is softened (softening step). Since the transfer body 11 and the mold 13 are strongly bonded to each other by, for example, vacuum adsorption via the heat generation layer 12, the heat generation layer 12 generates heat by irradiation of the electromagnetic wave 14, and the transfer surface 11a of the transfer body 11 is transferred. Is softened, the transfer surface 11a of the transfer body 11 is deformed according to the uneven shape of the uneven surface 13a of the mold 13. Needless to say, the softening point or melting point of the material constituting the mold must be equal to or higher than the softening point or melting point of the material constituting the transfer target.

  Here, it is necessary that at least one of the transfer target 11 and the mold 13 is made of a material that transmits the electromagnetic wave 14. When the mold 13 is made of a material that transmits the electromagnetic wave 14, the heat generation layer 12 is irradiated with the electromagnetic wave 14 through the mold 13 as shown in FIG. When the transfer body 11 is made of a material that transmits the electromagnetic wave 14, the heat generation layer 12 is irradiated with the electromagnetic wave 14 through the transfer body 11 as shown in FIG.

  Further, when both the transfer target 11 and the mold 13 are made of a material that transmits the electromagnetic wave 14, the electromagnetic wave 14 is transmitted to the heat generating layer 12 through the mold 13 as shown in FIG. As shown in FIG. 4B, the heat generation layer 12 may be irradiated with the electromagnetic wave 14 through the transfer target 11, but as shown in FIG. It is preferable to irradiate the heat generating layer 12 with the electromagnetic wave 14 through the transfer body 11.

  This is because when the electromagnetic wave 14 is irradiated to the heat generating layer 12 through the mold 13, there is a possibility that the electromagnetic wave 14 may be interfered by the uneven shape of the uneven surface 13 a of the mold 13. This is because when the interference occurs, the electromagnetic wave 14 is not uniformly applied to the heat generating layer 12, which may cause a decrease in the accuracy of the concavo-convex shape transferred to the transfer surface 11 a of the transfer target 11. On the other hand, in the case where the heat generating layer 12 is irradiated with the electromagnetic wave 14 via the transfer target 11, the transfer of the transfer target 11 is continued until the heat generation layer 12 generates heat and the transfer surface 11a of the transfer target 11 is softened. Since the transfer surface 11a is flat, the above problem does not occur.

  The wavelength of the electromagnetic wave 14 is preferably 2000 nm or less. This is because there are few heat generating materials that sufficiently absorb electromagnetic waves at wavelengths longer than 2000 nm. Laser light is most preferable as the electromagnetic wave 14. This is because by using laser light, the light intensity per unit area on the heat generating layer 12, that is, the energy density can be increased. Furthermore, a semiconductor laser is particularly preferable as the laser that emits laser light. This is because the semiconductor laser is small and easy to maintain, low cost and long life.

  The softening process shown in FIG. 4 preferably includes a focusing process for focusing the electromagnetic wave 14 emitted from the light source on the heat generating layer 12. The electromagnetic wave 14 can be efficiently irradiated by the focusing process. Further, when imprinting is performed by two-dimensionally moving an optical head (not shown) having a light source that emits electromagnetic waves 14 or the transfer target 11 and the mold 13 or both, focus servo is performed in the focusing process. It is preferable to carry out. By executing the focus servo, it is possible to eliminate the mechanical error and reliably focus the electromagnetic wave 14 on the heat generating layer 12, and to realize a good imprint.

  Here, the case where imprinting is performed by two-dimensionally moving an optical head (not shown) having a light source that emits the electromagnetic wave 14 or the transfer target 11 and the mold 13 or both, is, for example, an embodiment described later. As shown in 1 etc., it refers to a case where an electromagnetic wave is irradiated while a vacuum-adsorbed mold and a transfer object are placed on a turntable and rotated. The focus servo can be realized by a known method used when focusing (condensing) laser light so as to follow the rotating optical recording medium during recording or reproduction of the optical recording medium.

  Next, in the step shown in FIG. 5, the mold 13 is released from the transfer target 11 (release step). Next, in the step shown in FIG. 6, by removing the heat generation layer 12 formed on the transfer surface 11a of the transfer body 11 (heat generation layer removal step), as shown in FIG. The uneven shape 13 a is transferred to the transfer surface 11 a of the transfer body 11. The heat generating layer 12 can be removed by wet etching, for example. Wet etching is etching using a liquid chemical having a property of corrosive dissolution of a target metal or the like.

  In the conventional imprinting method, a transfer surface of a transfer object that is made of a material that does not transmit electromagnetic waves is irradiated with electromagnetic waves through a mold that is made of a material that transmits electromagnetic waves. The transfer surface of the mold was softened, and the uneven shape of the uneven surface of the mold was transferred to the transfer surface of the transfer body. That is, the material constituting the mold is limited to a material that transmits electromagnetic waves, and the material that forms the transfer target is limited to a material that does not transmit electromagnetic waves (a material that absorbs electromagnetic waves and generates heat).

  In the imprint method according to the first embodiment of the present invention, the heat generation layer 12 that absorbs the electromagnetic wave 14 and generates heat is formed on the transfer surface 11a of the transfer body 11, and the heat generation layer 12 is irradiated with the electromagnetic wave 14. In order to heat the heat generating layer 12 and soften the transferred surface 11a of the transferred body 11, it is sufficient that at least one of the transferred body 11 and the mold 13 is made of a material that transmits electromagnetic waves.

  That is, according to the imprint method according to the first embodiment of the present invention, a mold made of a material that transmits electromagnetic waves, which is a conventional imprint method, and a cover made of a material that does not transmit electromagnetic waves. Of course, it is composed of a combination of a mold that is made of a material that does not transmit electromagnetic waves and a transfer body that is made of a material that transmits electromagnetic waves, and a material that transmits electromagnetic waves. Imprinting can be performed even in a combination of a mold and a transfer target composed of a material that transmits electromagnetic waves, and a more practical imprinting method can be realized.

<Second Embodiment>
The imprint method according to the second embodiment of the present invention will be described with reference to FIGS. The imprint method according to the second embodiment of the present invention is characterized in that a mold having two concavo-convex surfaces is used and two concavo-convex surfaces are transferred to the transfer surface of the transfer object. This is different from the imprint method according to the first embodiment.

  9 to 15 are schematic views illustrating an imprint method according to the second embodiment of the invention. 9 to 15, reference numerals 21 and 31 denote transferred materials, reference numerals 22 and 32 denote heat generating layers, reference numeral 23 denotes a mold, and reference numeral 24 denotes an electromagnetic wave. Reference numerals 21a and 31a denote transfer surfaces of the transfer bodies 21 and 31, and 23a and 23b denote uneven surfaces of the mold 23.

First, in the process shown in FIG. 9, transferred objects 21 and 31 are prepared, and heat generating layers 22 and 32 are formed on the transferred surfaces 21 a and 31 a of the transferred objects 21 and 31 (heat generating layer forming process). Examples of the material of the transferred bodies 21 and 31 include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, silicon resin, fluorine resin, ABS resin, and urethane. Resins typified by resins, oxides typified by SiO ₂ , Al ₂ O ₃ , nitrides typified by SiN, AlN, carbides typified by SiC and GC (glassy carbon), etc. A material used as a so-called substrate such as Si or a ceramic material, or Si can be used. The heat generating layers 22 and 32 absorb the electromagnetic wave 24 irradiated through the transferred bodies 21 and 31 made of a material that transmits the electromagnetic wave 24 in the step shown in FIG. This is a layer composed of a heat generating material that generates a quantity of heat sufficient to soften the 31 transfer surfaces 21a and 31a. Since the adjustment of the amount of heat generated in the heat generating layers 22 and 32 and the materials constituting the heat generating layers 22 and 32 are the same as in the case of the heat generating layer 12 in the imprint method according to the first embodiment of the present invention, The description is omitted.

Next, in a process shown in FIG. 10, a mold 23 having uneven surfaces 23a and 23b is manufactured (mold manufacturing process). The uneven surfaces 23a and 23b are surfaces having a nanoscale uneven pattern, for example. Examples of the material of the mold 23 include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, silicon resin, fluorine resin, ABS resin, and urethane resin. Resins, oxides typified by SiO ₂ , Al ₂ O ₃ , nitrides typified by SiN, AlN, etc., crystals or ceramics such as carbides typified by SiC or GC (glassy carbon) A material and a mold material generally used in a nanoimprint method such as a metal material typified by Ni or Ta can be used, but a film-like material is particularly preferable. The uneven surfaces 23a and 23b of the mold 23 can be formed by, for example, FIB (Focused Ion Beam) processing or the like. As is well known, FIB (Focused Ion Beam) processing is a processing method that uses a finely focused Ga (gallium) ion beam, and a complicated shape can be produced with submicron level accuracy.

  Next, in the step shown in FIG. 11, the heat generation layers 22 and 32 formed on the transfer surfaces 21a and 31a of the transfer bodies 21 and 31 are brought into contact with the convex portions of the uneven surfaces 23a and 23b of the mold 23. The contact is performed by strongly pressing the transferred bodies 21 and 31 and the mold 23 with an external pressure. As a specific method of contact, a method of pressing with a mechanical force using a dedicated pressing machine may be used. However, a vacuum is applied between the heat generation layers 22 and 32 and the concave and convex surfaces 23a and 23b of the mold 23 to externally. A method using vacuum adsorption in which pressure bonding is performed by the atmospheric pressure is preferable (vacuum adsorption step). Since vacuum suction is the same as in the case of the imprint method according to the first embodiment of the present invention, description thereof is omitted.

  Next, in the process shown in FIG. 12, the heat generating layers 22 and 32 are irradiated with the electromagnetic wave 24 through the transferred bodies 21 and 31 made of a material that transmits the electromagnetic wave 24, thereby causing the heat generating layers 22 and 32 to generate heat. Thus, the transfer surfaces 21a and 31a of the transfer bodies 21 and 31 are softened (softening step). Since the transfer bodies 21 and 31 and the mold 23 are strongly bonded by, for example, vacuum suction via the heating layers 22 and 32, the heating layers 22 and 32 generate heat by irradiation of the electromagnetic wave 24, and the transfer body is transferred. When the transferred surfaces 21 a and 31 a of 21 and 31 are softened, the transferred surfaces 21 a and 31 a of the transferred bodies 21 and 31 are deformed according to the uneven shape of the uneven surfaces 23 a and 23 b of the mold 23. Needless to say, the softening point or melting point of the material constituting the mold must be equal to or higher than the softening point or melting point of the material constituting the transfer target.

  Here, it is necessary that both the transfer target members 21 and 31 are made of a material that transmits the electromagnetic wave 24. The electromagnetic wave 24 may be sequentially applied to the heat generating layers 22 and 32 via the transfer target 21 or 31, but the electromagnetic wave 24 is simultaneously applied to the heat generating layers 22 and 32 from both sides of the transfer target 21 and 31. Productivity can be improved. Since the wavelength of the electromagnetic wave 24 is the same as that of the electromagnetic wave 14 in the imprint method according to the first embodiment of the present invention, the description thereof is omitted.

  The softening process shown in FIG. 12 preferably includes a focusing process for focusing the electromagnetic wave 24 emitted from the light source on the heat generating layers 22 and 32. The electromagnetic wave 24 can be efficiently irradiated by the focusing process. Further, when imprinting is performed by two-dimensionally moving an optical head (not shown) having a light source that emits an electromagnetic wave 24 or the transferred objects 21 and 31 and the mold 23, or both, It is preferable to execute the servo. By executing the focus servo, it is possible to eliminate the mechanical error and reliably focus the electromagnetic wave 24 on the heat generating layers 22 and 32. As a result, it is possible to realize a good imprint.

  Here, the case where imprinting is performed by two-dimensionally moving an optical head (not shown) having a light source that emits the electromagnetic wave 24 or the transferred bodies 21 and 31 and the mold 23, or both, will be described later, for example. As shown in Example 1 or the like, it refers to a case in which electromagnetic waves are irradiated while a vacuum-adsorbed mold and a transfer target are placed on a turntable and rotated. The focus servo can be realized by a known method used when focusing (condensing) laser light so as to follow the rotating optical recording medium during recording or reproduction of the optical recording medium.

  When electromagnetic waves are simultaneously irradiated from both sides of the transferred body while the vacuum-adsorbed mold and the transferred body are placed on the turntable and rotated, for example, two A mechanism different from that of a conventional information recording / reproducing apparatus having an optical head is required, but such a mechanism can be realized within the scope of the prior art.

  Next, in the step shown in FIG. 13, the mold 23 is released from the transferred bodies 21 and 31 (release step). Next, in the step shown in FIG. 14, the heat generation layers 22 and 32 formed on the transfer surfaces 21a and 31a of the transfer bodies 21 and 31 are removed (heat generation layer removal step), as shown in FIG. The uneven shapes of the uneven surfaces 23 a and 23 b of the mold 23 are transferred to the transfer surfaces 21 a and 31 a of the transfer bodies 21 and 31. The heat generating layers 22 and 32 can be removed by wet etching, for example. Wet etching is etching using a liquid chemical having a property of corrosive dissolution of a target metal or the like.

  In the conventional imprinting method, a transfer surface of a transfer object that is made of a material that does not transmit electromagnetic waves is irradiated with electromagnetic waves through a mold that is made of a material that transmits electromagnetic waves. The transfer surface of the mold was softened, and the uneven shape of the uneven surface of the mold was transferred to the transfer surface of the transfer body. That is, the material constituting the mold is limited to a material that transmits electromagnetic waves, and the material that forms the transfer target is limited to a material that does not transmit electromagnetic waves (a material that absorbs electromagnetic waves and generates heat). It was not possible to perform double-sided imprinting by contacting the transfer object.

  In the imprint method according to the second embodiment of the present invention, the heat generation layers 22 and 32 that generate heat by absorbing the electromagnetic wave 24 are formed on the transfer surfaces 21 a and 31 a of the transfer bodies 21 and 31. And 32 are irradiated with the electromagnetic wave 24, the heat generating layers 22 and 32 are heated, and the transferred surfaces 21a and 31a of the transferred bodies 21 and 31 made of a material that transmits the electromagnetic waves are softened. The concavo-convex shapes of the concavo-convex surfaces 23 a and 23 b are transferred to the transfer surfaces 21 a and 31 a of the transfer bodies 21 and 31.

  That is, according to the imprint method according to the second embodiment of the present invention, unlike the conventional imprint method, it is possible to use a transfer body made of a material that transmits electromagnetic waves. A highly practical imprint method (double-sided imprint method) can be realized. In addition, according to the imprint method according to the second embodiment of the present invention, it is possible to realize an imprint method (double-sided imprint method) that is fast and excellent in productivity.

<Example 1>
FIG. 16 is a plan view illustrating a schematic shape of the mold 43 used in Example 1 of the present invention. FIG. 17 is a cross-sectional view illustrating the schematic shape of the mold 43 used in Example 1 of the present invention. The mold 43 shown in FIGS. 16 and 17 is a substrate used for an HD DVD-RW disc made of polycarbonate resin having a diameter of about φ120 mm, a thickness of about 0.6 mm, and a central hole diameter of about φ15 mm. A groove 45 having a track pitch TP1 = about 400 nm, a groove (recess) width W1 = about 200 nm, and a depth D1 = about 27 nm is formed in a spiral shape in the range of about φ48 to φ118 mm on one side of the mold 43. Yes. Unless otherwise specified in the first embodiment, the mold pattern indicates the spiral groove 45. The surface of the mold 43 on which the groove 45 is formed is referred to as an uneven surface 43a.

  FIG. 18 is a diagram for explaining the bonded sample 46. A substrate made of a polycarbonate resin having the same external dimensions as the mold 43 and having no grooves 45 formed thereon was prepared for the transfer target 41. A Ge film (film thickness: about 10 nm) was formed as a heat generating layer 42 on the transfer surface 41a of the transfer body 41 by sputtering. As shown in FIG. 18, the heat generation layer 42 formed on the transfer surface 41 a of the transfer body 41 and the protrusions of the uneven surface 43 a of the mold 43 are brought into contact with each other in a vacuum to maintain vacuum suction. A bonded sample 46 was prepared.

  POP120-7A manufactured by Hitachi Computer Equipment Co., Ltd. was used as the irradiation device that radiates electromagnetic waves. This irradiation apparatus is used for initialization of a phase change optical recording medium, and is equipped with an optical head having a semiconductor laser having a wavelength of about 830 nm, which is an electromagnetic wave light source. This optical head has an autofocus servo mechanism, and condenses laser light emitted from a semiconductor laser, which is an electromagnetic wave light source, on the heat generation layer 42 of the bonded sample 46. The size of the focused beam is about 75 μm long and about 1 μm wide in the radial direction of the bonded sample 46.

  The imprint itself is almost the same as the initialization of the phase change optical recording medium. The bonded sample 46 is placed on the turntable provided in the irradiation device, rotated at an arbitrary rotation number, and the focus servo is executed. The laser beam was irradiated from the transferred object 41 side. Further, while irradiating the laser beam, the optical head was moved in the radial direction of the bonded sample 46, and the entire range where the groove 45 was formed was irradiated with the laser beam.

  Note that tracking servo is not executed when the laser beam is irradiated. In Example 1, imprinting was performed under the setting conditions as shown in Table 1. Under this condition, the work is completed in about 40 seconds per sheet. However, in Example 1, the work was stopped halfway so that the imprint state could be seen.

After irradiating the laser beam, the transferred object 41 and the mold 43 are peeled off, and the transferred surface 41a of the transferred object 41 that is in contact with the uneven surface 43a of the mold 43 is visually observed. Since the interference color due to the light interference was observed in the same manner as above, it was found that the uneven shape of the uneven surface 43a of the mold 43 was imprinted on the transfer surface 41a of the transfer body 41. In addition, the interference color of the transfer surface 41a of the transfer body 41 is no longer the portion where the laser beam irradiation is stopped, and the interference color cannot be confirmed at the outer peripheral portion. I understood.

  Furthermore, in order to confirm by other methods that the uneven shape of the uneven surface 43a of the mold 43 is imprinted on the transfer surface 41a of the transfer body 41, an Ag film is formed on the transfer surface 41a of the transfer body 41. About 200 nm. For comparison, an Ag film having a thickness of about 200 nm was also formed on the uneven surface 43 a of the mold 43.

  After depositing the Ag film, the signal of the imprinted surface 41a of the imprinted object 41 in the tracking servo Off and On is checked using an optical disk evaluation apparatus (ODU-1000 manufactured by Pulstec). It was. FIG. 19 is a diagram showing the total light amount signal 47, the trigger signal 48, and the push-pull signal 49 when the tracking servo is turned off. Here, the total light quantity signal 47 is a signal indicating the reflectance, the trigger signal 48 is a signal representing the time corresponding to one round, and the push-pull signal 49 is a signal used for a tracking error signal or the like. The horizontal axis indicates time, and the vertical axis indicates voltage. In FIG. 19, since the push-pull signal 49 is observed, it can be seen that the uneven shape of the uneven surface 43 a of the mold 43 is imprinted on the transfer surface 41 a of the transfer body 41.

  FIG. 20 is a diagram showing the total light amount signal 47, the trigger signal 48, and the push-pull signal 49 when the tracking servo is turned on. Here, the total light quantity signal 47 is a signal indicating the reflectance, the trigger signal 48 is a signal representing the time corresponding to one round, and the push-pull signal 49 is a signal used for a tracking error signal or the like. The horizontal axis indicates time, and the vertical axis indicates voltage. In FIG. 20, since the tracking servo can be executed without any problem, it can be seen that the uneven shape of the uneven surface 43a of the mold 43 is imprinted satisfactorily on the transfer surface 41a of the transfer body 41. In the evaluation by this optical disk evaluation apparatus, the same result was obtained in all the areas irradiated with laser.

  According to the present invention, unlike the conventional imprint method, the heat generation layer 42 that generates heat by absorbing electromagnetic waves is formed on the transfer surface 41a of the transfer body 41, and the heat generation layer 42 is irradiated with electromagnetic waves. Since the surface 42a of the transfer body 41 is softened by generating heat, the imprint method can be imprinted on the transfer body 41 made of a material that transmits electromagnetic waves, and is more practical. Can be realized.

  The effects of the present invention are not limited to the materials and layer configurations used in Example 1, the duplicating apparatus, the duplicating method, and the evaluation apparatus.

<Examples 2 to 9>
In Examples 2 to 9, as in Example 1, the heat generating layer 42 was formed on the transfer surface 41a of the transfer object 41 by sputtering. First, in Examples 2 to 4, Ge was used as the material of the heat generating layer 42, and the film thicknesses shown in Table 2 were formed and imprinted. The results are shown in Table 2 at the same time, and it has been found that there is an optimum range for imprinting on the Ge film thickness. The reason for this is that if the Ge film is too thin, the laser beam cannot be sufficiently absorbed and the amount of heat generated for imprinting does not occur. Conceivable.

Next, in Examples 5 to 9, Ag was used as the material of the heat generating layer 42, and the film thicknesses shown in Table 3 were formed and imprinted. The results are shown in Table 3 at the same time, but could not be imprinted regardless of the Ag film thickness. The reason for this is considered that the thermal conductivity of Ag itself is too high, so that the amount of heat necessary for imprinting cannot be generated.

  In Tables 2 and 3, the film thickness was measured using a spectroscopic ellipsometer (JA.Woollam M2000DI). The presence or absence of a groove signal by the optical disk evaluation apparatus was determined by whether or not a push-pull signal at the time of tracking servo off shown in FIG. 19 can be observed.

The results shown in Tables 2 and 3 indicate that the amount of heat generated for imprinting can be adjusted by the amount of heat generated by the heat generating material constituting the heat generating layer 42 with respect to the laser light, the thermal conductivity, and the thickness of the heat generating layer 42. It is very important. This is a content that could not be found in the prior art.

  According to the present invention, unlike the conventional imprint method, the heat generation layer 42 that generates heat by absorbing electromagnetic waves is formed on the transfer surface 41a of the transfer body 41, and the heat generation layer 42 is irradiated with electromagnetic waves. Since the surface 42a of the transfer body 41 is softened by generating heat, the imprint method can be imprinted on the transfer body 41 made of a material that transmits electromagnetic waves, and is more practical. Can be realized.

  The effects of the present invention are not limited to the materials and layer configurations used in this embodiment, the duplicating apparatus, the duplicating method, and the evaluation apparatus.

<Example 10>
In Example 10, double-sided imprinting was performed using a commercially available hologram sheet as the mold 53. FIG. 21 is a photomicrograph of the hologram sheet that is the mold 53. The hologram sheet as the mold 53 shown in FIG. 21 is a rectangular parallelepiped thin sheet having an outer shape of 25 × 20 × 0.1 mm. FIG. 22 is an AFM image showing the unevenness of the hologram sheet as the mold 53, which was evaluated using an AFM apparatus (VN-8000 manufactured by Keyence Corporation). The evaluation of the AFM image shown in FIG. 22 confirmed that the hologram sheet as the mold 53 had irregularities with a height of about 130 nm and a pitch of about 800 nm (hereinafter, the hologram sheet as the mold 53 has an irregular surface. (It is referred to as “uneven surface 53a”).

  FIG. 23 is a diagram for explaining the bonded sample 56. Two molds 53 were prepared. In addition, substrates to be transferred 51 and 61 are prepared by a substrate made of polycarbonate resin having the same outer dimensions as the mold 43 shown in FIG. Ge films (thickness: about 10 nm) were formed as the heat generating layers 52 and 62 on the transfer surfaces 51a and 61a of the transfer bodies 51 and 61 by sputtering. As shown in FIG. 23, the two molds 53 do not overlap with each other with the concave / convex surface 53a of one mold 53 facing upward and the concave / convex surface 53a of the other mold 53 facing downward. The heat generation layer 52 formed on the convex portion of the one uneven surface 53a and the transferred surface 51a of the transferred body 51, and the convex portion of the other uneven surface 53a and the transferred surface 61a of the transferred body 61 are formed. The heat generation layer 62 was brought into contact with each other in a vacuum, and bonded together in a state where the vacuum suction was maintained, whereby a bonded sample 56 was produced.

  The bonded sample 56 thus produced was irradiated with laser light using the same apparatus and procedure as in Example 1. However, due to the dimensional relationship between the mold 53 and the transferred bodies 51 and 61, there is a portion where the mold 53 is not sandwiched between the transferred bodies 51 and 61. When the autofocus mechanism is used, there is no mold 53. Fixed focus was used because the device stopped at that point. As the setting conditions, the conditions shown in Table 4 were used.

After irradiating the laser beam one side at a time, the transferred objects 51 and 61 are peeled off, and the transferred surfaces 51 a and 61 a of the transferred objects 51 and 61 that are in contact with the mold 53 are visually observed. Interference color due to interference was observed. FIG. 24 is a photomicrograph of the transferred surface 51a of the transferred object 51. FIG. 25 is an AFM image showing the state of the transfer surface 51a of the transfer object 51, and is evaluated using an AFM apparatus (VN-8000 manufactured by Keyence Corporation). From the evaluation of the AFM image shown in FIG. 25, it was confirmed that the transfer surface 51a of the transfer target 51 had irregularities with a height of about 70 nm and a pitch of about 820 nm. In the same way, it was confirmed that the transfer surface 61a of the transfer body 61 also has the same unevenness as the transfer surface 51a of the transfer body 51.

  The concavo-convex shape transferred to the transfer surfaces 51 a and 61 a of the transfer bodies 51 and 61 is about half the height of the concavo-convex shape of the concavo-convex surface 53 a of the hologram sheet as the mold 53. Good imprint. The reason why the height is reduced to about half is considered to be that the focus of the laser beam is fixed and the focus is insufficient, and a sufficient amount of heat generation cannot be obtained. From this, it can be said that the shape and size of the transfer target can be adjusted by adjusting the irradiation condition of the laser beam (particularly the parameter relating to the light intensity).

  In Example 10, for convenience of the experimental environment, two hologram sheets having a concavo-convex surface 53 a on one side are used as the mold 53, and the other mold 53 is provided with the concavo-convex surface 53 a of one mold 53 facing upward. With the concave and convex surface 53a facing downward, the two molds 53 are overlapped in a vacuum so as to be sandwiched between the transferred bodies 51 and 61 so that the vacuum suction is maintained so that the two molds 53 do not overlap. Bonding and a bonding sample 56 were produced.

  However, from the results of Example 10, as shown in the second embodiment of the present invention, two transferred objects that are made of a material that transmits electromagnetic waves using a mold having uneven surfaces on both sides are used. It is easily imagined that double-sided imprinting can be realized by irradiating electromagnetic waves through two transferred materials with a mold interposed therebetween.

  According to the present invention, double-sided imprinting is possible, and a more practical imprinting method can be realized. Further, according to the present invention, it is possible to realize an imprint method that is fast and excellent in productivity. The effects of the present invention are not limited to the materials and layer configurations used in this embodiment, the duplicating apparatus, the duplicating method, and the evaluation apparatus.

<Example 11>
In Example 11, similarly to Example 1, a Ge film (film thickness: about 10 nm) was formed as a heat generating layer 42 on the transfer surface 41a of the transfer object 41 by a sputtering method. As the mold, a quartz substrate having the same shape as that of the mold 43 used in Example 1 was prepared, and a textured structure shown in FIG. 26 was prepared on the surface of the prepared quartz substrate. FIG. 26 is a photomicrograph of a textured structure produced on the surface of a quartz substrate that is a mold. The size of the texture structure shown in FIG. 26 is a dot pitch of 400 nm and a height of 500 nm. The texture structure shown in FIG. 26 corresponds to the uneven surface 43a of the first embodiment. The texture structure refers to a repetitive pattern that can be arranged according to a predetermined rule, such as a structure having a large number of minute uneven shapes on the surface.

  Subsequently, the texture structure produced on the surface of the quartz substrate as a mold was transferred to the transfer surface 41a of the transfer target 41 by the same method as in Example 1. FIG. 27 is a diagram illustrating a light transmission spectrum of the transfer target 41 to which the texture structure is transferred. In FIG. 27, Δ is the transferred object 41 having the texture structure transferred to the transferred surface 41a, × is the quartz substrate that is a mold having the texture structure formed on the surface used for transfer, and ○ is FIG. 2 shows a quartz substrate having no texture structure formed on the surface. The transmittance of the mold and the quartz substrate (without the texture structure) is described for comparison with the transmittance of the transfer target 41.

  As shown in FIG. 27, the quartz substrate (×) used for the transfer as the mold 41 (Δ) is also a quartz substrate (600) having a texture structure on the surface in the wavelength region of 600 nm or more. The transmittance is higher than ○). This is due to the antireflection effect of the texture structure, and the transfer target 41 exhibits the same characteristics as the quartz substrate used for transfer as a mold, so that it can be seen that good transfer is performed. .

  From the above results, the present invention can also imprint a mold having a texture structure on the surface.

  The effects of the present invention are not limited to the materials and layer configurations used in this embodiment, the duplicating apparatus, the duplicating method, and the evaluation apparatus.

<Example 12>
In Example 12, as in Example 1, a Ge film (film thickness: about 10 nm) was formed as a heat generating layer 42 on the transfer surface 41a of the transfer object 41 by sputtering. And the bonding sample 46 was produced similarly to Example 1, and it imprinted by irradiating the laser beam to the bonding sample 46 from the mold 43 side. The transferred object 41 thus produced was scanned 2500 tracks (about 1 mm width) while tracking using the optical disk evaluation apparatus used in Example 1. At this time, the rotational linear velocity of the transfer object 41 was changed as shown in Table 5, and the presence or absence of tracking off was confirmed. ○ indicates that there is no tracking error, and × indicates that there is tracking error. For comparison, the case of Example 1 is also shown. As shown in Table 5, it was confirmed that, in the transferred object 41 imprinted by irradiating the laser beam from the mold 43 side in Example 12, the tracking out occurred when the rotational linear velocity was higher than a predetermined value.

From the above results, it is possible to realize an imprint method in which transferability is further improved when laser light is incident from the transfer target side.

  The effects of the present invention are not limited to the materials and layer configurations used in this embodiment, the duplicating apparatus, the duplicating method, and the evaluation apparatus.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and the above-described embodiments can be performed without departing from the scope of the present invention. Various modifications and substitutions can be added to the embodiments and examples.

FIG. 3 is a schematic diagram (part 1) illustrating the imprint method according to the first embodiment of the invention. FIG. 6 is a schematic diagram (part 2) illustrating the imprint method according to the first embodiment of the invention. FIG. 6 is a schematic diagram (part 3) illustrating the imprint method according to the first embodiment of the invention; FIG. 6 is a schematic diagram (part 4) illustrating the imprint method according to the first embodiment of the invention; FIG. 10 is a schematic diagram (part 5) illustrating the imprint method according to the first embodiment of the invention; FIG. 10 is a schematic diagram (part 6) illustrating the imprint method according to the first embodiment of the invention; FIG. 10 is a schematic diagram (part 7) illustrating the imprint method according to the first embodiment of the invention; It is a figure which illustrates typically the relationship between the amount of absorption with respect to electromagnetic waves 14, the heat conductivity, the film thickness of the heat generating layer 12, and the amount of heat generated in the heat generating layer 12. It is a schematic diagram (the 1) which illustrates the double-sided imprint method which concerns on the 2nd Embodiment of this invention. FIG. 6 is a schematic diagram (part 2) illustrating a double-sided imprint method according to a second embodiment of the invention. FIG. 10 is a schematic diagram (part 3) illustrating the double-sided imprint method according to the second embodiment of the invention; FIG. 10 is a schematic diagram (part 4) illustrating a double-sided imprint method according to the second embodiment of the invention; FIG. 10 is a schematic diagram (part 5) illustrating a double-sided imprint method according to the second embodiment of the invention; FIG. 10 is a schematic diagram (part 6) illustrating a double-sided imprint method according to the second embodiment of the invention; FIG. 14 is a schematic diagram (part 7) illustrating the double-sided imprint method according to the second embodiment of the invention; It is a top view which illustrates the schematic shape of the mold 43 used in Example 1 of this invention. It is sectional drawing which illustrates the schematic shape of the mold 43 used in Example 1 of this invention. It is a figure for demonstrating the bonding sample 46. FIG. It is a figure which shows the total light quantity signal 47, the trigger signal 48, and the push pull signal 49 at the time of tracking servo Off. It is a figure which shows the total light quantity signal 47, the trigger signal 48, and the push pull signal 49 at the time of tracking servo On. 3 is a photomicrograph of a hologram sheet that is a mold 53; 4 is an AFM image showing the unevenness of a hologram sheet that is a mold 53; It is a figure for demonstrating the bonding sample 56. FIG. 2 is a photomicrograph of a transferred surface 51a of a transferred body 51. 2 is an AFM image showing a state of a transfer surface 51a of a transfer object 51. It is a microscope picture of the texture structure produced on the surface of the quartz substrate which is a mold. It is a figure which illustrates the light transmission spectrum of the to-be-transferred body 41 to which the texture structure was transcribe | transferred.

Explanation of symbols

11, 21, 31, 41, 51, 61 Transfer object 11a, 21a, 31a, 41a, 51a, 61a Transfer object surface of transfer object 12, 22, 32, 42, 52 Heat generation layer 13, 23, 43, 53 Molds 13a, 23a, 23b, 43a, 53a Uneven surface of the mold 14, 24 Electromagnetic wave 45 Groove 46, 56 Bonded sample 47 Total light quantity signal 48 Trigger signal 49 Push-pull signal

Claims (15)

In a state where the uneven surface of the mold having the uneven surface and the transferred surface of the transfer object are in contact with each other, electromagnetic waves are applied to soften the transferred surface, and the uneven shape of the uneven surface is transferred to the transferred surface. An imprint method for transferring to a surface,
A heat generation layer forming step of forming a heat generation layer that absorbs the electromagnetic wave and generates heat on the transfer surface;
A softening step in which at least one of the heat generation layer is irradiated with the electromagnetic wave through the mold or the transfer target body made of a material that transmits the electromagnetic wave, and the heat generation layer generates heat to soften the transfer surface. And an imprint method characterized by comprising: In a state where the two uneven surfaces of the mold having two uneven surfaces and the two transferred surfaces of the two transferred objects are in contact with each other, electromagnetic waves are applied to soften the two transferred surfaces, An imprint method for transferring the uneven shape of the two uneven surfaces to the two transferred surfaces,
A heat generating layer forming step of forming a heat generating layer that absorbs the electromagnetic wave and generates heat on the two transferred surfaces;
A softening step of irradiating the heat generating layer with the electromagnetic waves through the two transferred bodies made of a material that transmits the electromagnetic waves, and heating the heat generating layers to soften the two transferred surfaces; The imprint method characterized by having.   3. The imprint method according to claim 2, wherein, in the softening step, the electromagnetic wave is simultaneously irradiated onto the heat generating layer through the two transferred objects.   Furthermore, the uneven surface of the mold is brought into contact with the heat generating layer formed on the transferred surface of the transferred body using vacuum suction between the heat generating layer forming step and the softening step. The imprint method according to claim 1, further comprising a vacuum suction step.   5. The imprint method according to claim 1, wherein the softening step includes a focusing step of focusing the irradiated electromagnetic wave on the heat generating layer. 6.   6. The imprint method according to claim 5, wherein focus servo is executed in the focusing step. Further, before the heat generation layer forming step, a mold manufacturing step of manufacturing the mold having the uneven surface,
The method further comprises: after the softening step, a release step of releasing the mold from the transferred body, and a heat generation layer removing step of removing the heat generation layer formed on the transfer surface. Item 7. The imprint method according to any one of Items 1 to 6.   The film thickness of the heat generating layer is determined in consideration of the amount of absorption of the electromagnetic wave and the thermal conductivity of the material constituting the heat generating layer. Imprint method.   The material constituting the heat generating layer is made of any one of a metal, a semiconductor, a dielectric, a semimetal, an organic material, or a mixture thereof. How to print.   The imprint method according to claim 9, wherein the material forming the heat generating layer includes a phase change material.   The imprint method according to claim 1, wherein the heat generating layer has a configuration in which a single layer or a plurality of layers are stacked.   The imprint method according to claim 1, wherein a maximum wavelength of the electromagnetic wave is 2000 nm or less.   The imprint method according to claim 1, wherein the electromagnetic wave is a laser beam.   The imprint method according to claim 13, wherein the laser that emits the laser light is a semiconductor laser.   The imprint method according to claim 1, wherein the mold has a film shape.