JP2008094082A - Fine processing method and fine processing substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the quality of a substrate having a fine uneven pattern on its surface and further thin and miniaturize the substrate. <P>SOLUTION: A tabular article to be processed having a smooth resin surface provided on at least one side thereof is used. During a die operation process wherein a die for punching the article to be processed into a predetermined shape is moved from an initial position to be returned to the initial position through a punching position, at least one of a transfer member having an uneven pattern formed on its surface and the article to be processed is raised in temperature by heating and, in this state, the uneven pattern of the transfer member is pressed to the resin surface of the article to be processed to perform a transfer process for transferring the uneven pattern to a place positioned with respect to a predetermined punching shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microfabrication method for forming a highly accurate mirror surface or a fine uneven pattern on a substrate surface, and a microfabrication substrate manufactured by the micromachining method.

  In general, as a typical molding method for optical components, an appropriate amount of molten resin is injected and filled into a cavity having a fixed volume with a mold temperature lower than the softening temperature of the molding resin, and after cooling while controlling the holding pressure, An injection molding method is known in which a mold is opened to take out a molded product.

  In the case of such an injection molding method, it is necessary to change the filling amount depending on the volume of the injection molded product, but if the volume becomes smaller than the predetermined range, the cylinder diameter of the injection molding machine is also changed to a smaller one. Otherwise, there is a problem that the control range of the molding conditions becomes narrow.

  A disk substrate is well known as an injection molded product having a uniform thickness and a fine pattern. The disk substrate is formed by bonding two sheets having an outer diameter of 120 mm, an inner diameter of 15 mm, and a thickness of 1.2 mm or 0.6 mm. The stamper, which is a transfer member, is a Ni plate having an outer diameter of 138 mm, an inner diameter of 22 mm or 34 mm, and a plate thickness of about 0.3 mm, and the inner peripheral portion is mechanically held on one side of the mold by a stamper presser of a mold part. .

  When molding such a disk substrate, the molten resin enters the cavity from the substrate center by the disk gate from the sprue bush of the mold, and immediately after the filling is completed, the inner diameter portion is punched by the cut punch of the mold. . The punched runner is cooled in a cooling water channel in the sprue bush and taken out as a cold runner.

  For this reason, the resin temperature on the inner circumference is high, the cooling proceeds and the resin temperature decreases as it goes to the outer circumference, resulting in a resin viscosity difference along the radial direction, and even if the pattern transfer on the inner circumference is good, There is a problem that the outer peripheral portion is insufficiently transferred.

  In the case of injection molding, as described above, the number of parts such as a stamper, a stamper presser, and a sprue bush increases. Therefore, in designing the machine, it is necessary to design a clearance in consideration of manufacturing tolerances of individual parts. For this reason, the eccentricity with respect to the fine pattern of the inner diameter portion of the disk substrate after molding is unavoidable, and it is inevitable to allow it up to about 10 to 15 μm.

  Furthermore, if the thickness of the substrate is further reduced (for example, 0.4 mm or less) for the purpose of reducing the diameter of the disk substrate, the cooling of the outer peripheral portion is further accelerated and the resin does not reach the outer periphery. Therefore, it is difficult to reduce the thickness of the disk substrate.

  Further, if the inner diameter of the substrate is further reduced (for example, 5 mm or less), it becomes difficult to manufacture a sprue bush, stamper presser, or cut punch with a mold, so it is difficult to reduce the diameter of the disk substrate. Met.

In addition, in recent years, a method has been proposed in which the substrate forming step and the transfer step are performed in separate steps. However, when the relative positional accuracy between the substrate and the concavo-convex pattern is strictly required at the nanometer level, such as a disk or a rotary encoder, positioning takes time. In addition, it is difficult to obtain desired accuracy due to deformation due to heat in the post-process or deviation during operation. Therefore, there is no case where a method of performing the substrate forming process and the transfer process in separate processes is applied to such fine processing.
JP 2002-0465151 A Japanese Patent Laid-Open No. 2003-118025

  In view of the above problems, the present inventor has intensively studied. As a result, the present inventor not only stabilizes the quality of a substrate having a fine uneven pattern on the surface, but also enables a further reduction in thickness and size. A fine processing method was found. In other words, a workpiece obtained by injection molding or extrusion molding is a flat blank substrate having a smooth surface and a uniform thickness. A fine uneven pattern is formed on the workpiece (blank substrate) by a transfer technique (imprint) using a press device during the mold operation process of the die for punching the blank substrate (workpiece) into a predetermined shape. Is formed (transfer process).

  In forming a workpiece by this method, it is only necessary to use a molding machine that is good at each, and the press device does not need to be changed depending on the volume of the molded product. In addition, fine transfer to thin substrates and small-diameter substrates has become possible by selecting the thickness of the workpiece and heating it uniformly with a heater.

  According to a first aspect of the present invention, there is provided a micromachining method according to claim 1, wherein a die for punching a flat workpiece having a smooth resin surface on at least one surface into a predetermined shape is returned from the initial position to the initial position through the punching position. During the mold operation step, in a state where at least one of the transfer member having a concavo-convex pattern formed on the surface or the workpiece is heated, the concavo-convex pattern of the transfer member is applied to the resin surface of the workpiece. It is characterized by performing a transfer step of applying pressure to transfer the uneven pattern to a position positioned with respect to the predetermined punching shape.

  According to a second aspect of the present invention, there is provided a micro-machining method in which a mold for punching a flat workpiece having a smooth resin surface on at least one side is moved from an initial position through a punching position to return to an initial position. A temperature raising step of heating at least one of the transfer member having a concavo-convex pattern formed thereon or the workpiece, a punching step of punching the workpiece into a predetermined shape, and a concavo-convex pattern of the transfer member Is applied to the resin surface of the workpiece to transfer the concavo-convex pattern to a position positioned with respect to the predetermined punching shape, and the concavo-convex pattern is transferred to the position where the concavo-convex pattern is positioned. And a cooling step for cooling the workpiece.

  The micromachining method according to claim 3 of the present invention is the micromachining method according to claim 2, wherein the temperature raising step, the punching step, the transfer step, and the cooling step are performed during the mold operation step. It is characterized by executing in order.

  A micromachining method according to a fourth aspect of the present invention is the micromachining method according to the second aspect, wherein the temperature raising step, the transfer step, the punching step, and the cooling step are performed during the mold operation step. It is characterized by executing in order.

  A micromachining method according to a fifth aspect of the present invention is the micromachining method according to any one of the second to fourth aspects, wherein in the punching step, a residual of the work piece outside the predetermined shape is obtained. The workpiece is punched into the predetermined shape with the portion fixed.

  A micromachining method according to a sixth aspect of the present invention is the micromachining method according to any one of the second to fifth aspects, wherein, in the cooling step, the transfer member and the workpiece are forced by a cooling gas. It is characterized by cooling.

  A micromachining method according to a seventh aspect of the present invention is the micromachining method according to any one of the second to sixth aspects, wherein the punched portion punched into the predetermined shape is a punching hole of the workpiece. It is automatically inserted into the portion and can be taken out substantially integrally.

  The micromachining method according to claim 8 of the present invention is the micromachining method according to any one of claims 2 to 7, wherein the smooth surface roughness Ra of the workpiece is 0.5 μm. It is characterized by the following.

  The micromachining method according to claim 9 of the present invention is the micromachining method according to any one of claims 2 to 8, wherein the predetermined shape for punching the workpiece in the punching step is a disc shape. It is characterized by that.

  A micromachining method according to a tenth aspect of the present invention is the micromachining method according to any one of the second to eighth aspects, wherein the predetermined shape for punching the workpiece in the punching step is circular at a center portion. It is characterized by a disk shape having holes.

  A microfabricated substrate according to an eleventh aspect of the present invention is manufactured by the microfabrication method according to any one of the second to eighth aspects.

  According to a twelfth aspect of the present invention, there is provided a disk substrate produced by the microfabrication method according to any one of the second to eighth aspects.

  According to a thirteenth aspect of the present invention, a rotary encoder substrate is produced by the microfabrication method according to any one of the second to eighth aspects.

  According to a fourteenth aspect of the present invention, at least one of the upper die and the lower die that can be heated has a punch fixed to the punch side holder, a hole through which the punch passes, and A stripper biased so as to return when it is pushed in on the basis of a position protruding from the front end surface of the punch, and the other is a die fixed to the die side holder, at least one side The substrate to be processed, which is provided with a smooth resin surface, is sandwiched between the stripper by driving the ram of the press device in the mold closing direction and further cooperates with the punch. A die for punching out the substrate to be processed, and a transfer member disposed in the inner space of the die and having a concavo-convex pattern formed on the surface thereof, and the concavo-convex pattern on the resin surface of the substrate to be processed A method of performing microfabrication using a mold having a pressurizing member capable of pressurization, wherein the punch and die are sandwiched from the initial position to the initial position through the punching position. A temperature raising step of heating at least one of the transfer member or the substrate to be processed by heating at least one of the upper die or the lower die during the mold operation step until returning, and the substrate to be processed has a predetermined shape A punching process for punching the sheet, a transfer process for pressing the uneven pattern of the transfer member against the resin surface of the substrate to be processed, and transferring the uneven pattern to a position positioned with respect to the predetermined punching shape; and A cooling step is performed for cooling the substrate to be processed, which has been transferred to the position where the uneven pattern is positioned.

  A micromachining method according to a fifteenth aspect of the present invention is the micromachining method according to the fourteenth aspect, wherein a member in contact with the pressing device of the upper die or the lower die to be heated is formed of a heat insulating material, and the upper die or It is characterized in that heat conduction from the lower mold to the pressing device is prevented.

  The micromachining method according to a sixteenth aspect of the present invention is the micromachining method according to the fourteenth or fifteenth aspect, wherein the temperature raising step raises the temperature of the transfer member by a heater provided in the pressure member, Further, when the substrate to be processed is sandwiched between the stripper and the die, the substrate to be processed in a portion sandwiched between the punch and the transfer member is heated by a heater provided in the punch. It is characterized by that.

  The microfabrication method according to a seventeenth aspect of the present invention is the micromachining method according to any one of the fourteenth to sixteenth aspects, wherein the workpiece is sandwiched between the stripper and the die. In this state, the portion of the substrate to be processed sandwiched between the punch and the transfer member is punched out as the predetermined shape.

  The microfabrication method according to an eighteenth aspect of the present invention is the microfabrication method according to any one of the fourteenth to seventeenth aspects, wherein the transfer step is performed after the temperature raising step, after the temperature raising step, between the punch and the transfer member. The pressurizing member causes the concavo-convex pattern of the transfer member to be transferred to the resin surface of the substrate to be processed in the sandwiched portion, thereby transferring the surface.

  The micromachining method according to a nineteenth aspect of the present invention is the micromachining method according to any one of the fourteenth to eighteenth aspects, wherein the cooling step cools an outer periphery of the punch with a cooling gas. The outer periphery of the pressurizing member is cooled with a working gas to cool the portion of the substrate to be processed that is sandwiched between the punch and the transfer member.

  A microfabrication method according to a twentieth aspect of the present invention is the microfabrication method according to any one of the fourteenth to nineteenth aspects, wherein the punched substrate punched into the predetermined shape is a punch hole of the substrate to be processed. It is automatically inserted into the portion and can be taken out substantially integrally.

  According to a twenty-first aspect of the present invention, at least one of an upper die and a lower die that can be heated has an outer punch that is fixed to a punch-side holder, and a hole through which the outer punch is passed. And a stripper that is biased so as to return when it is pushed in on the basis of the position protruding from the tip surface of the outer punch, and the other is a die fixed to the die side holder The substrate to be processed, which has a smooth resin surface on at least one side, and is placed between both molds, is sandwiched between the stripper by driving the ram of the press device in the mold closing direction, Further, an outer shape die that punches the workpiece substrate in cooperation with the outer shape punch, and is fixed to the die side holder concentrically with the outer shape die, and the center position of the outer shape punch The inner die punch for punching the substrate to be processed in cooperation with the inner die punching hole formed in the inner die punching hole is disposed in the inner space of the outer die so as to avoid the inner die punch, and the surface is uneven. This is a method of performing microfabrication using a mold provided with a transfer member having a pattern formed at the tip and a pressing member capable of pressing the uneven pattern against the resin surface of the substrate to be processed. During the mold operation process until the outer punch, the outer die and the inner punch are returned from the initial position to the initial position through the punching position and the punching position, A temperature raising step for heating at least one of the transfer member or the substrate to be processed by heating at least one of the molds, a punching step for punching the substrate to be processed into a predetermined shape, and irregularities on the transfer member A transfer step of applying pressure to the resin surface of the substrate to be processed and transferring the uneven pattern to a position positioned with respect to the predetermined punching shape; and transferring the uneven pattern to the position where the uneven pattern is positioned. And a cooling step for cooling the processed substrate.

  A microfabrication method according to a twenty-second aspect of the present invention is the micromachining method according to the twenty-first aspect, wherein the punched substrate punched into the predetermined shape is a punched hole in the remaining portion of the substrate to be processed outside the punched substrate. The two are automatically inserted and can be taken out substantially integrally.

  A micromachining method according to a twenty-third aspect of the present invention is the micromachining method according to the twenty-first or twenty-second aspect, wherein a compressed gas is ejected from a split surface between the inner punch and the pressure member when the mold is opened. Thus, the punched substrate punched into a predetermined shape from the substrate to be processed in the punching step is released from the uneven pattern of the transfer member.

  A micromachining method according to a twenty-fourth aspect of the present invention is the micromachining method according to any one of the twenty-first to twenty-third aspects, wherein compressed gas is ejected from the contact surface of the stripper with the substrate to be processed when the mold is opened. Thus, the remaining portion of the substrate to be processed outside the punched substrate punched into a predetermined shape in the punching step is released.

  A microfabrication method according to a twenty-fifth aspect of the present invention is the micromachining method according to any one of the twenty-first to twenty-fourth aspects, wherein in the outer shape die, the substrate to be processed is cooperated with the outer shape punch. A die main part that also serves as a punching part for punching and a sandwiching part for sandwiching the substrate to be processed between the stripper is configured as a separate part from the other parts, The die main part is exchanged with respect to the part.

  As described above, the present invention is in the mold operation process until the mold for punching a flat workpiece having a smooth resin surface on at least one side into a predetermined shape returns from the initial position to the initial position through the punching position. In addition, in a state where at least one of the transfer member having a concavo-convex pattern formed on the surface or the workpiece is heated, the concavo-convex pattern of the transfer member is pressed against the resin surface of the workpiece, In addition to being able to stably produce and produce a high-quality substrate having a fine concavo-convex pattern on the surface because a transfer process is performed to transfer the concavo-convex pattern to a position positioned with respect to the predetermined punching shape. Thus, further reduction in thickness and size can be realized.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 and FIG. 2 are schematic views in cross section of a main part showing an embodiment of a mold (imprint mold) used in the microfabrication method according to the present invention. The mold (imprint mold) 10 includes a lower mold fixed to a lower ram of a press device (not shown) and an upper mold fixed to an upper ram of the press device.

  The lower die includes an outer shape (outer diameter) punch 20 and a stripper 25, and further includes a lower holder 30 and a lower back plate 35.

  The outer shape (outer diameter) punch 20 is fitted from below into a fitting hole formed at the center position of the lower holder 30. The lower back plate 35 is fixed to the lower holder 30 with bolts, whereby the outer shape (outer diameter) punch 20 is positioned and fixed at the center position of the lower holder 30.

  The outer shape (outer diameter) punch 20 has a structure in which heaters and temperature sensors that are equally arranged in the circumferential direction can be installed, although not shown.

  The stripper 25 has a substrate outer hole having a required gap between the stripper 25 and the outer shape (outer diameter) punch 20. The gap is set to a very small gap that allows the stripper 25 to slide up and down with respect to the outer shape (outer diameter) punch 20.

  Further, the stripper 25 is fixed to the upper end portion of the stripper collar 26 that is penetrated from below through four through holes formed at intervals of 90 ° in the circumferential direction with respect to the centers of the lower holder 30 and the lower back plate 35. Is done.

  Four stripper springs 27 are attached to the lower end portion of the stripper collar 26, and a spring pressing plate 28 that presses the lower end of the stripper spring 27 is fixed to the lower back plate 35 with bolts. The spring retainer plate 28 can be fixed to the lower ram of the press device. The spring retainer plate 28 is preferably made of a heat insulating material so that the heat of the heater installed in the outer shape (outer diameter) punch 20 is not transmitted to the press device.

  Thus, the stripper 25 is positioned slightly higher than the upper end surface of the outer shape (outer diameter) punch 20 by the four stripper collars 26 and the four stripper springs 27 at the time of no load before pressing, that is, 2 mm or less. It is preferably positioned at a height raised upward by about 0.3 to 0.5 mm (see FIG. 1).

  Such a stripper 25 functions as follows when a blank substrate (not shown) larger than the outer shape (outer diameter) punch 20 is placed on the stripper 25 and the upper ram of the press device is lowered. That is, as the upper ram descends, the spring force of the stripper spring 27 starts from the moment when the blank substrate is sandwiched between the lower end surface of the outer (outer diameter) die 50 described later and the upper end surface of the stripper 25. Press down the blank board.

  Further, the stripper 25 prevents the molded substrate after the imprinting from adhering to the upper end surface of the outer shape (outer diameter) punch 20 when the upper ram is raised. It works to be pulled away from the upper end surface of 20 by 2 mm or less, preferably about 0.3 to 0.5 mm upward.

  Furthermore, the lower holder 30 is formed with four press-fitting holes formed at intervals of 90 ° in the circumferential direction with respect to the center thereof, and four guide bushes 40 are press-fitted into the press-fitting holes, It is installed with the axis vertical.

  The upper die includes an outer shape (outer diameter) punching die 50, a stamper 55, and a piston 56, and further includes an upper holder 60 and an upper back plate 65.

  The outer shape (outer diameter) punching die 50 is formed with a board outer hole having a required gap between the stamper 55 and the small diameter portion of the piston 56 to which the stamper 55 is attached at the center thereof. The clearance is set to a very small clearance that allows the outer (outer diameter) punching die 50 to slide up and down relatively with respect to the small diameter portions of the stamper 55 and the piston 56.

  The outer shape (outer diameter) punching die 50 is precisely positioned by a dowel pin (not shown) at the center position of the upper holder 60 and fixed by a bolt. The outer shape (outer diameter) punching die 50 includes an air cylinder portion 51.

  The stamper 55 is provided with a fine concavo-convex pattern on one side (the lower surface in FIG. 1) in an arrangement with a desired dimension with respect to the shape of the stamper. Further, the other one surface (the upper surface in FIG. 1) is fixed with a bolt so as to be adhered or detachable so as to be in close contact with the piston 56.

  The piston 56 is provided with an O-ring 57 on the outer periphery. The piston 56 can be pressurized during imprinting by supplying air from the air supply port 61 of the upper holder 60 to the air cylinder portion 51 in the outer (outer diameter) punching die 50.

  Although not shown, the piston 56 has a structure in which heaters and temperature sensors arranged evenly in the circumferential direction can be installed. Thereby, the piston 56 can also perform heating at the time of imprinting.

  Further, the upper back plate 65 is fixed to the upper holder 60 with bolts so that it can be fixed to the upper ram of the press device. The upper back plate 65 is preferably a heat insulating material so that the heat of the heater installed on the piston 56 is not transmitted to the press device.

  Further, the upper holder 60 is formed with four press-fitting holes formed at intervals of 90 ° in the circumferential direction with reference to the center thereof, and four guide posts 70 are press-fitted into the press-fitting holes. Are installed vertically. The guide post 70 and the guide bush 40 are configured to be precisely fitted by a ball bearing (not shown) so that the upper mold and the lower mold can be positioned accurately.

  When the upper ram of the press device is lowered, the outer shape (outer diameter) punch 20 enters the outer shape (outer diameter) punching die 50 while maintaining a uniform punching clearance with respect to the die hole of the outer shape (outer diameter) punching die 50 as shown in FIG. It has a structure to do.

  In this embodiment, the stamper 55 and the piston 56 are two separate parts. However, the present invention is not limited to this, and the stamper 55 and the piston 56 may be integrated into one part.

  The micromachining method according to the present invention using the mold (imprint mold) 10 configured as described above uses a transfer member (stamper 55) having a fine concavo-convex pattern on the surface, and the concavo-convex pattern is the surface. This is a method for producing a microfabricated substrate of a predetermined shape formed in the above.

  That is, in this micromachining method, a plate-shaped workpiece (blank substrate) having a smooth resin surface on at least one surface during a mold operation process from the initial position through the punching position to return to the initial position. ) Or in a state where at least one of the stampers 55 is heated by heating, the uneven pattern of the stamper 55 is pressed against the resin surface of the blank substrate, and the uneven pattern is positioned with respect to the predetermined punched shape of the blank substrate. Is to be transferred to.

  Specifically, this microfabrication method includes a temperature raising step for heating at least one of the stamper 55 or the blank substrate during the mold operation step of the mold 10, a punching step for punching the blank substrate into a predetermined shape, A transfer process of pressing the concave / convex pattern of the stamper 55 against the resin surface of the blank substrate and transferring the concave / convex pattern to a position where the concave / convex pattern is positioned with respect to a predetermined punching shape of the blank substrate; A cooling step for cooling the transferred blank substrate is performed.

  In the microfabrication method, during the mold operating process of the mold 10, the temperature raising process, the punching process, the transfer process, and the cooling process can be executed in this order.

  Moreover, this microfabrication method can perform a heating process, a transfer process, a punching process, and a cooling process in this order during the mold operating process of the mold 10.

  In the punching step, it is preferable that the blank substrate (workpiece) is punched in a state of being fixed outside the predetermined shape to be punched.

  The surface roughness Ra of the surface of the workpiece (blank substrate) is 0.5 μm or less. The surface roughness Ra is defined by JIS_B_0601-1994. This is because, when the surface roughness Ra of the surface of the workpiece (blank substrate) is 0.5 μm or more, the visibility with the concavo-convex pattern to be transferred is deteriorated. The surface roughness Ra can be measured by an atomic force microscope (AFM), a stylus type surface roughness meter, an optical interference type surface roughness meter, or the like according to JIS_B — 0601-1994.

  The workpiece (blank substrate) may be a flat plate made of a thermoplastic resin, a thermosetting resin or an ultraviolet curable resin, or a thermoplastic resin, a thermosetting resin or an ultraviolet curable resin on the substrate surface. It may be a composite type flat plate to which is applied.

  Examples of the thermoplastic resin include polycarbonate resin, polyarylate resin, polyethersulfone resin, polysulfone resin, polyester resin, polymethyl methacrylate resin, polyetherimide resin, cycloolefin polymer resin, polyethylene terephthalate resin, polyamide resin, and the like. It can be suitably used.

  As the thermosetting resin, an epoxy resin is particularly preferably used from the viewpoint of hue. Examples of the epoxy resin include bisphenol A type, bisphenol F type, bisphenol S type and bisphenol types such as hydrogenation thereof, novolak types such as phenol novolak type and cresol novolak type, and triglycidyl isocyanurate type. Nitrogen-containing ring type, such as hindantoin type, alicyclic type, aliphatic type, aromatic type such as naphthalene type, low water absorption type such as glycidyl ether type, biphenyl type, dicyclo type, ester type, ether ester type, etc. These modified types are exemplified.

  These may be used alone or in combination. Among the various epoxy resins, it is preferable to use a bisphenol A type epoxy resin, an alicyclic epoxy resin, or a triglycidyl isocyanurate type epoxy resin from the viewpoint of preventing discoloration.

  As an ultraviolet curable resin, the composition containing the component of a urethane (meth) acrylate or an epoxy (meth) acrylate oligomer, a reaction diluent, a photoinitiator, and a photosensitizer is mentioned, for example. However, it is not particularly limited.

  As the substrate, for example, an acrylic resin, MS resin, polycarbonate resin, polyester resin, polystyrene resin, polyolefin resin, vinyl chloride resin, polyimide resin, or a sheet or film made of a blend of the above resins can be suitably used. From the viewpoint of releasability from the mold, flexible acrylic resin, polycarbonate resin, polyester resin, MS resin and the like are preferable from the viewpoint of light transmittance and flexibility.

  The microfabricated substrate obtained by the microfabrication method of the present invention includes a rotary encoder substrate, a disk substrate, a hard disk substrate, a light guide plate, a touch panel substrate, a fuel cell separator, a reflector, a biochip, a lens, etc. Means various substrates.

  Next, an embodiment of imprinting on a substrate when the fine processing method according to the present invention is performed using the mold (imprint mold) 10 configured as described above will be described.

  First, the heater provided in the outer shape (outer diameter) punch 20 and the piston 56 is energized, and the outer shape (outer diameter) punch 20, the piston 56 and the stamper 55 are brought to the glass transition temperature of synthetic resin around −10 to + 40 ° C. Set.

  In this state, a flat blank substrate made of a synthetic resin and having a thickness of about 0.5 mm and a surface roughness Ra of 0.005 μm is placed on the stripper 25. Then, the upper ram position of the press device is lowered by a predetermined amount from the initial value, the blank substrate is sandwiched between the stripper 25 and the outer shape (outer diameter) punching die 50, and the upper surface of the stripper 25 is the outer shape (outer diameter) punching punch 20. Push until it matches the top surface. The position of the upper ram of the press device at this time is set as a holding value (see FIG. 9).

  At this position, the blank substrate is sandwiched between the outer shape (outer diameter) punching punch 20 and the stamper 55 by putting an appropriate low-pressure air into the air cylinder portion 51. In this state, the blank substrate is held for a predetermined time until the temperature is raised to a temperature suitable for the punching process (temperature raising process).

  After the blank substrate is held for a predetermined time required to raise the temperature (temperature raising step), the upper ram is further lowered to lower the bottom dead center as shown in FIG. Accordingly, the blank substrate is punched into a predetermined outer shape (outer diameter) shape by the outer shape (outer diameter) punch 20 and the outer shape (outer diameter) punching die 50 (punching step). At this time, the peripheral substrate (outer substrate) between the stripper 25 and the outer shape (outer diameter) punching die 50 is opposed to the substrate to be punched out on the upper surface of the outer shape (outer diameter) punch 20 (punched substrate). Going down.

  The press position by the upper ram is held at this bottom dead center position (see FIG. 9). At this position, the internal pressure of the air cylinder portion 51 is appropriately increased and adjusted so that the applied pressure is 2 to 3 MPa with respect to the area of the stamper 55. Thus, a process (transfer process) in which a fine uneven pattern applied to the stamper 55 is imprinted on the punched substrate is entered. The imprint (transfer process) takes about 5 to 240 seconds depending on the resin used and the fine uneven pattern.

  Note that the air pressure in the air cylinder 51 is not limited to the method of switching from the low pressure in the temperature raising process and the punching process to the high pressure in the transfer process as described above. That is, as long as there is no problem in punching even at a predetermined high pressure, the pressing force of 2 to 3 MPa may be kept constant with respect to the area of the stamper 55 from the punching process.

  In this case, in the temperature raising step, the pressure can be kept low, or the blank substrate is sandwiched between the stamper 55 and the outer shape (outer diameter) punch 20 by the weight of the piston 56 without applying pressure. You can also.

  After the imprint (transfer process) is completed, the heaters provided in the outer shape (outer diameter) punch 20 and the piston 56 are turned off, and the temperature of the outer shape (outer diameter) punch 20 and the piston 56 is changed to the glass transition temperature -5 to -40. Enter the cooling process to lower to around ℃. At this time, the air pressure in the air cylinder portion 51 may be switched to a low pressure as appropriate.

  In the cooling process, the mold parts and the molded substrate (punching / transfer substrate) around the stamper 55, such as the stamper 55 and the piston 56, are forced to use a cooling gas such as N2 in order to shorten the processing time. It is desirable to cool down.

  When the temperature of the outer shape (outer diameter) punch 20 and the piston 56 falls to the set temperature, the upper ram is raised and returned to the initial value. Thereby, mold opening is performed (refer FIG. 9). At this time, for example, by releasing release air from the divided surfaces of the piston 56 and the stamper 55 and the outer shape (outer diameter) punching die 50, the release of the molded substrate and the surrounding outer substrate and the upper die is promoted. Is preferred. Similarly, for example, it is preferable to urge release of the molded substrate and the surrounding outer substrate and the lower die by blowing release air from the dividing surface of the outer shape (outer diameter) punch 20 and the stripper 25.

  In addition, since the clearance between the outer diameter of the outer shape (outer diameter) punch 20 and the inner diameter of the outer shape (outer diameter) punching die 50 is very small, the stripper 25 is restored by urging at the time of mold opening, so that a predetermined amount is obtained. The punched substrate (molded substrate) punched into the shape is automatically inserted into the punched hole in the remaining portion (outer substrate) of the blank substrate. Thereby, the molded substrate and the outer substrate are taken out substantially integrally (substrate release step). FIG. 9 shows an example of a timing chart of each process based on the mold operating process of the mold described above.

  As described above, an imprint molding substrate in which a fine uneven pattern is transferred to a position positioned with respect to a predetermined punching shape by entering an imprint process during a mold operation process while pressing a blank substrate is created. Can do.

  In addition, although the fine unevenness | corrugation processing is given to the lower surface of the stamper 55, the same fine unevenness | corrugation processing can be given also to the upper end surface of the external shape (outer diameter) punching punch 20, for example. In this way, it is also possible to produce a molded substrate in which imprints with fine irregularities are formed on both the front and back surfaces.

  In addition, the air cylinder 51 is configured to be pressurized during imprinting by supplying air. For example, the piston position is controlled by a connecting pin or the like from the upper ram side of the press device. Thus, pressurization during imprinting may be realized.

  In this embodiment, the procedure for entering the imprint process (transfer process) is taken when the upper ram position reaches the bottom dead center, that is, after the punching process. However, the present invention is not limited to this. Depending on the material of the blank substrate, for example, the upper ram position is at the hold value and the imprint process (transfer process) starts after the temperature raising process, and then the upper ram is lowered to the bottom dead center, It is also possible to take a procedure of punching into an (outer diameter) shape (punching process) and finally entering a cooling process.

  3-7 is the schematic which made the principal part the cross section which shows other embodiment of the metal mold | die (imprint metal mold | die) used for the microfabrication method by this invention in cross section. The mold (imprint mold) 110 is generally the same as the mold (imprint mold) 10 shown in FIGS. 1 and 2 as a whole. A reference numeral added with 100 is added to the reference numeral used in FIG.

  This mold (imprint mold) 110 is greatly different from the mold (imprint mold) 10 shown in FIGS. 1 and 2 in that not only the outer shape (outer diameter) but also the inner shape (inner diameter) is punched concentrically. Different. Therefore, the upper mold is provided with an inner shape (inner diameter) punch 175, and the lower mold is provided with an inner shape (inner diameter) punching die hole 145.

  That is, the inner shape (inner diameter) punch 175 is fitted into a hole formed at the center position of the upper holder 160 and is positioned concentrically with the outer shape (outer diameter) punch 150. Further, the inner shape (inner diameter) punch 175 can receive a punching load by the upper back plate 165. Further, an O-ring 176 is installed in the inner shape (inner diameter) punch 175 so that air from the air cylinder portion 151 does not escape.

  In the center of the stamper 155, an inner shape (inner diameter) hole is formed with a very small clearance (one side of 3 μm or less) that can slide with respect to the inner shape (inner diameter) punch 175. On the surface of one side of the stamper 155 (the lower surface in FIG. 3), a fine concavo-convex pattern is processed on the circumference concentrically with the inner shape (inner diameter) hole. An escape hole for the inner shape (inner diameter) punch 175 is also formed in the center of the piston 156.

  The inner shape (inner diameter) punching die hole 145 is formed at the center position of the outer shape (outer diameter) punching punch 120. Then, as shown in FIG. 5, the inner shape (inner diameter) punch 175 enters the punch diameter while maintaining a uniform punch clearance.

  Next, an embodiment of imprinting onto a small-diameter disk substrate or rotary encoder substrate when the fine processing method according to the present invention is performed using the mold (imprint mold) 110 configured as described above. Will be described.

  First, the heaters provided in the outer shape (outer diameter) punch 120 and the piston 156 are energized, and the outer shape (outer diameter) punch 120, the piston 156 and the stamper 155 are set around 160 ° C.

  In this state, a flat blank substrate made of polycarbonate resin and having a surface roughness of 0.002 μm is placed on the stripper 125 (see FIG. 3). Then, the upper ram of the press device is lowered by a predetermined amount, the blank substrate is sandwiched between the stripper 125 and the outer shape (outer diameter) punching die 150, and the upper surface of the stripper 125 matches the upper surface of the outer shape (outer diameter) punching punch 120. Push in until you see (see Fig. 4). The position of the upper ram of the press device at this time is set as a holding value (see FIG. 9).

  At this position, the blank substrate is held for a predetermined time until the temperature rises to a temperature suitable for the punching process (around 150 ° C.), and then the upper ram is further lowered to lower the bottom dead center as shown in FIG. As a result, the blank substrate is punched into a predetermined outer shape (outer diameter) by the outer shape (outer diameter) punch 120 and the outer shape (outer diameter) punching die 150, and the inner shape (inner diameter) punch 175 and the inner shape are punched out. A (inner diameter) punching die hole 145 is punched into a predetermined inner shape (inner diameter) shape. At this time, the residue punched out from the inner shape (inner diameter) of the blank substrate falls down from the inner shape (inner diameter) punching die hole 145.

  The press position by the upper ram is held at this bottom dead center position (see FIG. 5). At this position, the internal pressure of the air cylinder portion 151 is appropriately increased and adjusted so that a pressing force of 2.5 MPa is applied to the area of the stamper 155. Thereby, the process (transfer process) in which the fine uneven | corrugated pattern given to the stamper 155 is imprinted on a shaping | molding board | substrate is entered. The imprint (transfer process) takes about 50 seconds.

  After the imprint (transfer process) is completed, the heater provided to the outer shape (outer diameter) punch 120 and the piston 156 is turned off, and the cooling process to lower the temperature of the outer shape (outer diameter) punch 120 and the piston 156 to around 140 ° C. enter. When the temperature of the outer shape (outer diameter) punch 120 and the piston 156 falls to the set temperature, the upper ram is raised and returned to the initial value.

  At the time of opening the mold, the punched molded substrate is pressed against the upper surface of the outer shape (outer diameter) punch 120 via the stamper 155 by the pressure of the piston 156. At the same time, the outer substrate located on the outer periphery of the molded substrate is pushed up by the spring force of the stripper 125. Since the clearance between the outer diameter of the outer shape (outer diameter) punch 120 and the inner diameter of the outer shape (outer diameter) punching die 150 is very small, the molded substrate is reinserted into the punched hole of the outer substrate (see FIG. 6). ).

  Since the substrate in this state is cooled first from the outer peripheral side, the outer periphery of the molded substrate is held so as to be fastened to the punched hole of the outer substrate, and becomes an integrated state. This substrate (molded substrate and outer substrate) can be mechanically released (substrate release step). Therefore, the molded substrate is also mechanically peeled off from the stamper 155 integrally with the outer substrate (see FIG. 7), and there is a great advantage that the stamper 155 need not be treated with a release agent or the like.

  Since the molded substrate taken out integrally with the outer substrate is once punched, it can be mechanically pushed out from the outer substrate.

  In the cooling step, it is desirable to forcibly cool using an appropriate cooling gas in order to shorten the processing time. An example is shown in FIG. That is, the cooling gas is introduced from the upper cooling gas introduction hole 152 to cool the outer periphery of the piston 156. Similarly, the cooling gas is introduced from the cooling gas introduction hole 136 of the lower mold, and the outer shape (outer diameter) punch 120 is cooled.

  In the substrate release step, it is desirable to forcibly release using an appropriate compressed gas. An example is shown in FIG. That is, a compressed gas (release gas) is introduced from the upper mold compressed gas introduction hole 153 so that the punched substrate (molded substrate) is easily released from the uneven pattern of the stamper 155 when the die is opened. (Inner diameter) Compressed gas is ejected from the dividing surface of the punch 175, the piston 156 and the stamper 155.

  Similarly, the substrate of the stripper 125 is introduced by introducing a compressed gas (release gas) from the lower mold compressed gas introduction hole 129 so that the outer substrate positioned on the outer periphery of the molded substrate is easily released when the mold is opened. Compressed gas is ejected from the contact surface.

  Furthermore, the outer shape (outer diameter) punching die 150 may not be integral. For example, the die main portion 150a that also serves as a punching portion for punching a blank substrate in cooperation with the outer shape (outer diameter) punching punch 120 and a sandwiching portion for sandwiching the blank substrate between the stripper 125, and other portions It is configured as a separate part from 150b. In such a divided die, for example, when the wear of the punched portion is severe, the die main portion 150a can be replaced with the other portion 150b.

  According to the above method, the fine uneven pattern is eccentric only by 3 μm on one side at the maximum with respect to the clearance of the inner shape (inner diameter) of the stamper 155 with respect to the inner shape (inner diameter) punch 175. ) There is no need to align the processing. Moreover, since the inner shape (inner diameter) punch 175 is positioned concentrically by the outer shape (outer diameter) punching die 150 and the upper holder 160, the outer shape (outer diameter) and inner shape (inner diameter) of the stamper (transfer member) 155. ) And a molded substrate having a substrate outer shape (outer diameter) with no eccentricity relative to the inner shape (inner diameter) of the substrate.

  Such a molded substrate having no eccentricity is particularly effective in the case of a product that rotates at high speed with reference to the inner diameter, such as a rotary encoder, because no blurring occurs during rotation.

  FIG. 10 is a perspective view of the small-diameter disk substrate 1 obtained as described above. FIG. 11 is a perspective view of the rotary encoder substrate 2 obtained in the same manner. In all cases, the eccentricity with respect to the fine uneven pattern in the inner diameter portion was 3 μm or less.

It is the schematic which shows the principal part of one Embodiment of the metal mold | die (imprint metal mold | die) used for the microfabrication method by this invention in cross section. It is the schematic of the state which lowered | hung the metal mold | die (imprint metal mold | die) of FIG. 1 to the bottom dead center. It is the schematic of the initial state which shows the principal part of other embodiment of the metal mold | die (imprint metal mold | die) used for the microfabrication method by this invention in cross section. It is the schematic of the state which lowered | hung the metal mold | die (imprint metal mold | die) of FIG. 3 to the holding position. It is the schematic of the state which lowered | hung the metal mold | die (imprint metal mold | die) of FIG. 3 to the bottom dead center. It is the schematic of the state which returned the metal mold | die (imprint metal mold | die) of FIG. 3 to the holding position. It is the schematic of the state which returned the metal mold | die (imprint metal mold | die) of FIG. 3 to the initial position. It is the schematic which shows the detail of each part in the metal mold | die (imprint metal mold | die) of FIG. It is a timing chart which shows an example of each process based on a mold operation process of a metallic mold (imprint metallic mold). It is a perspective view which shows an example of the board | substrate for disks obtained by the microfabrication method of this invention. It is a perspective view which shows an example of the board | substrate for rotary encoders obtained by the microfabrication method of this invention.

Explanation of symbols

1 Disc substrate 2 Rotary encoder substrate 10, 110 Mold (imprint mold)
20, 120 Outer (outer diameter) punch 25, 125 Stripper 26, 126 Stripper collar 27, 127 Stripper spring 28, 128 Spring retainer plate 129 Lower mold compressed gas (release gas) introduction hole 30, 130 Lower holder 35 , 135 Lower back plate 136 Lower die cooling gas introduction hole 40, 140 Guide bush 145 Inner shape (inner diameter) die hole 50, 150 Outer die (outer diameter) die 51, 151 Air cylinder portion 152 Upper die cooling Gas inlet hole 153 Upper mold compressed gas (release gas) inlet hole 55, 155 Stamper 56, 156 Piston (pressurizing member)
57,157 O-ring 60,160 Upper holder 61,161 Air supply port 65,165 Upper back plate 70,170 Guide post 175 Inner shape (inner diameter) punch 176 O-ring

Claims (25)

During the mold operation process until the mold for punching a flat plate-like workpiece having a smooth resin surface on at least one side returns to the initial position from the initial position through the punching position,
In a state where at least one of the transfer member having a concavo-convex pattern formed on the surface or the workpiece is heated by heating, the concavo-convex pattern of the transfer member is pressed against the resin surface of the workpiece, A fine processing method, comprising performing a transfer step of transferring a pattern to a position positioned with respect to the predetermined punching shape. During the mold operation process until the mold for punching a flat plate-shaped workpiece having a smooth resin surface on at least one side returns to the initial position from the initial position through the punching position,
A temperature raising step of raising the temperature of at least one of the transfer member having the concavo-convex pattern formed thereon or the workpiece by heating,
Punching process for punching the workpiece into a predetermined shape,
A transfer step of pressing the concavo-convex pattern of the transfer member against the resin surface of the workpiece and transferring the concavo-convex pattern to a position positioned with respect to the predetermined punching shape; and the concavo-convex pattern is the positioning A cooling step of cooling the workpiece transferred to the place
A fine processing method characterized in that   The micromachining method according to claim 2, wherein the temperature raising step, the punching step, the transfer step, and the cooling step are executed in this order during the mold operation step.   3. The micromachining method according to claim 2, wherein the temperature raising step, the transfer step, the punching step, and the cooling step are executed in this order during the mold operating step.   5. The punching process according to claim 2, wherein in the punching step, the workpiece is punched into the predetermined shape in a state where a remaining portion of the workpiece outside the predetermined shape is fixed. The fine processing method according to claim 1.   6. The microfabrication method according to claim 2, wherein in the cooling step, the transfer member and the workpiece are forcibly cooled by a cooling gas.   The punched portion punched into the predetermined shape is automatically inserted into a portion of the punched hole of the workpiece so that the two can be taken out substantially integrally. The microfabrication method according to any one of the above.   The micromachining method according to any one of claims 2 to 7, wherein a surface roughness Ra of the smooth resin surface of the workpiece is 0.5 µm or less.   The micromachining method according to any one of claims 2 to 8, wherein the predetermined shape for punching the workpiece in the punching step is a disc shape.   The micromachining method according to any one of claims 2 to 8, wherein the predetermined shape for punching the workpiece in the punching step is a disc shape having a circular hole in a central portion.   A microfabricated substrate produced by the microfabrication method according to claim 2.   A disk substrate produced by the microfabrication method according to claim 2.   A substrate for a rotary encoder produced by the microfabrication method according to any one of claims 2 to 8. Either the upper mold or the lower mold, at least one of which can be heated,
A punch fixed to the punch side holder,
A stripper that has a hole through which the punch passes and is biased so as to return when pressed from a position protruding from the tip surface of the punch,
The other is
A die fixed to a die-side holder, provided with a smooth resin surface on at least one side, and a substrate to be processed placed between both dies, when the ram of the press device is driven in the mold closing direction, A die which is sandwiched between a stripper and punches the substrate to be processed in cooperation with the punch;
Gold provided with a transfer member disposed at the inner space of the die and having a concavo-convex pattern formed on the surface thereof, and a pressing member capable of pressing the concavo-convex pattern against the resin surface of the substrate to be processed A method for performing microfabrication using a mold,
During the mold operation process until the punch and die return from the initial position to the initial position through the clamping position and the punching position for punching,
A temperature raising step of raising the temperature of at least one of the transfer member or the substrate to be processed by heating at least one of the upper die or the lower die;
A punching process for punching the substrate to be processed into a predetermined shape;
A transfer step of pressing the concavo-convex pattern of the transfer member against the resin surface of the substrate to be processed, and transferring the concavo-convex pattern to a position positioned with respect to the predetermined punching shape; and the concavo-convex pattern is the positioning A cooling step of cooling the substrate to be processed transferred to the place,
A fine processing method characterized in that   The member which contacts the said press apparatus of the said upper mold | type or the lower mold | type heated is comprised with a heat insulating material, The heat conduction from the said upper mold | type or a lower mold | type to the said press apparatus is prevented. Fine processing method.   In the temperature raising step, the temperature of the transfer member is raised by a heater provided in the pressurizing member, and the heater provided in the punch when the substrate to be processed is sandwiched between the stripper and the die. 16. The microfabrication method according to claim 14, wherein the temperature of the substrate to be processed at a portion sandwiched between the punch and the transfer member is increased by the step.   In the punching step, the substrate to be processed is punched as the predetermined shape in a portion sandwiched between the punch and the transfer member in a state where the substrate to be processed is sandwiched between the stripper and the die. The microfabrication method according to any one of claims 14 to 16, characterized in that   In the transfer step, after the temperature raising step, the pressure member adds a concavo-convex pattern of the transfer member to the resin surface of the substrate to be processed that is sandwiched between the punch and the transfer member. The fine processing method according to claim 14, wherein the transfer is performed by pressing.   In the cooling step, the outer periphery of the punch is cooled by a cooling gas, and the outer periphery of the pressure member is cooled by a cooling gas, so that the portion of the portion sandwiched between the punch and the transfer member is cooled. The fine processing method according to claim 14, wherein the substrate to be processed is cooled.   20. The punched substrate punched into the predetermined shape is automatically inserted into a punched hole portion of the substrate to be processed, and the two can be taken out substantially integrally. The microfabrication method according to any one of the above. Either the upper mold or the lower mold, at least one of which can be heated,
An outline punch fixed to the punch side holder,
A stripper that has a hole through which the outer punch is passed, and is biased so as to return when it is pushed in with respect to a position protruding from the tip surface of the outer punch,
The other is
A die fixed to a die-side holder, provided with a smooth resin surface on at least one side, and a substrate to be processed placed between both dies, when the ram of the press device is driven in the mold closing direction, An outer die that is sandwiched between a stripper and punches the workpiece substrate in cooperation with the outer punch;
An inner die punch that is fixed to the die side holder concentrically with the outer die, and punches the workpiece substrate in cooperation with an inner die punching hole formed at the center position of the outer punch,
A transfer member that is arranged in the inner space of the outer shape punch die so as to avoid the inner shape punch and is provided with a concavo-convex pattern on the surface thereof, and the concavo-convex pattern is pressed against the resin surface of the substrate to be processed A method of performing microfabrication using a mold provided with a possible pressure member,
During the mold operation process until the outer punch, the outer die and the inner punch are returned from the initial position to the initial position through the punching position and the punching position for punching,
A temperature raising step of raising the temperature of at least one of the transfer member or the substrate to be processed by heating at least one of the upper die or the lower die;
A punching process for punching the substrate to be processed into a predetermined shape;
A transfer step of pressing the concavo-convex pattern of the transfer member against the resin surface of the substrate to be processed, and transferring the concavo-convex pattern to a position positioned with respect to the predetermined punching shape; and the concavo-convex pattern is the positioning A cooling step of cooling the substrate to be processed transferred to the place,
A fine processing method characterized in that   The punched substrate punched into the predetermined shape is automatically inserted into a punched hole in the remaining portion of the substrate to be processed outside thereof, and both can be taken out substantially integrally. The fine processing method according to claim 21.   When the mold is opened, the transfer substrate is formed by punching a punched substrate that has been punched into a predetermined shape from the substrate to be processed in the punching step by ejecting compressed gas from the divided surface of the inner punch and the pressure member. 23. The microfabrication method according to claim 21, wherein the mold is released from the uneven pattern.   When the mold is opened, the remaining portion of the substrate to be processed outside the punched substrate punched into a predetermined shape in the punching process is ejected from the contact surface of the stripper with the substrate to be processed. 24. The microfabrication method according to any one of claims 21 to 23, wherein the mold is released.   In the outer shape punching die, a die main portion serving as a punching portion for punching the workpiece substrate in cooperation with the outer shape punching punch and a clamping portion for sandwiching the workpiece substrate between the stripper, 25. The microfabrication according to any one of claims 21 to 24, wherein the die main part is configured as a separate part from the other part, and the die main part is exchanged for the other part of the outer die. Method.

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