JP4457340B2 - Processing method, mold, reproduction method and reproduction apparatus - Google Patents

Description

  The present invention relates to a processing method, a mold, a molding method, a molding apparatus, a regeneration method, a regeneration apparatus, and an optical element, and in particular, a treatment method capable of performing fluorine coating, a mold having a fine shape, a molding method, a molding apparatus, a regeneration method, and a regeneration. The present invention relates to an apparatus and an optical element.

  In recent years, optical elements such as objective lenses with extremely high accuracy are used in the field of optical pickup devices that are rapidly developing. When a material such as plastic or glass is molded into such an optical element using a mold, a product having a uniform shape can be quickly produced. It can be said that it is suitable for mass production.

  Furthermore, recent optical pickup devices use a light beam from a semiconductor laser with a shorter wavelength to record high-density information on a recording medium such as an AOD (Advanced Optical Disc) or BD (Blueray Disc) and / or What can be reproduced has been developed, and in order to improve aberration characteristics of the optical system, a diffractive structure which is a fine structure is provided on the optical surface. Further, even in an optical pickup device capable of recording and / or reproducing such high-density information, it is necessary to ensure the recording and / or reproducing of information even with respect to CDs and DVDs that have conventionally been supplied in large quantities. For this reason, a diffractive structure having wavelength selectivity is also provided.

  Here, although the diffraction structure depends on the wavelength of the light source to be used, for example, since the step is a ring zone structure having a minimum level of about 2 μm, in ordinary injection molding, the molten resin is simply injected into the mold. There is a problem that the material is difficult to enter deep in the depth of the formed fine structure, so that the fine structure is not accurately transferred. If the designed diffractive structure is not formed due to transfer defects (sagging of the material), the diffraction characteristics deteriorate, and there is a possibility that a write error or the like occurs in the optical pickup device using such an optical element. For this reason, various ideas such as selection of materials and adjustment of the temperature and pressure of the molten resin have been made. However, it is difficult to completely eliminate sagging with conventional methods.

On the other hand, Patent Document 1 below discloses a method of molding an optical element having a fine pattern on the surface by pressing a glass material in a heat-softened state.
Japanese Patent Laid-Open No. 2002-220241

  However, the technique described in Patent Document 1 is limited to molding a fine shape having a width of about 100 to 50 μm and a height of about 20 to 10 μm with an aspect ratio of about 0.2 on the surface of the glass material. . This is because the elastic modulus of inorganic glass at room temperature is as high as about 70 GPa, so even if a mold heated with a very large force of 3000 N is pressed on its surface, the glass material does not flow smoothly into the back of the microstructure, As a result, only a fine shape having an aspect ratio of about 0.2 could be formed. Therefore, for example, a molded product having a fine shape with an aspect ratio of 1 or more may exist as a prototype, but it does not yet exist as an industrial product with a uniform shape.

  In addition, in recent years, an attempt has been made to add a new optical function to an optical element by applying a fine structure smaller than several times the wavelength of a light source to be used to the optical surface. For example, the normal focusing function due to refraction of a molded lens and the positive dispersion that occurs as a side effect at that time are utilized by utilizing the large negative dispersion due to diffraction obtained by forming a diffraction groove on the surface of the aspheric optical surface. Of these, it has been put to practical use with a pickup objective lens for an optical disk compatible with DVD / CD to add an achromatic function, which is essentially impossible with refraction alone, to a single optical element. This utilizes the diffractive action of a diffraction groove having a size several tens of times the wavelength of light transmitted through the optical element, and the region that handles the diffractive action by a structure sufficiently larger than the wavelength is called a scalar region. It is.

  On the other hand, it has been found that the light reflection suppressing function can be exhibited by forming the conical projections densely on the surface of the optical surface at a minute interval of a fraction of the wavelength of the light transmitted through the optical element. Yes. That is, the refractive index change at the interface with the air when the light wave enters the optical element is not instantaneously changed from 1 to the medium refractive index as in the conventional optical element, but is arranged at a fine interval. By changing the shape of the protrusions gradually, the reflection of light can be suppressed. The optical surface on which such protrusions are formed has a fine structure called a so-called “eyes”, and individual structures can no longer be obtained by arranging structures finer than the wavelength of light with a period shorter than the wavelength. It works as an average refractive index for light waves without being diffracted. Such a region is generally called an equivalent refractive index region. Regarding such an equivalent refractive index region, see, for example, IEICE Transactions C Vol. J83-C No. 3pp. 173-181, described in March 2000.

  According to the microstructure of the equivalent refractive index region, it is possible to obtain a large antireflection effect while reducing the angle dependency and wavelength dependency of the antireflection effect as compared with the conventional antireflection coating, but according to plastic molding or the like, Since the optical surface and fine structure can be created at the same time, the lens function and the antireflection function can be obtained at the same time, and there is also a great merit in production such that post-processing such as antireflection coating treatment after molding is unnecessary as in the past. It is considered and is attracting attention. Furthermore, if such a fine structure of the equivalent refractive index region is arranged so as to have directionality with respect to the optical surface, it is possible to give the optical surface strong optical anisotropy. Thus, the birefringent optical element produced can be obtained by molding, and a new optical function can be added in combination with a refractive or reflective optical element. The optical anisotropy in this case is called structural birefringence.

  Between the above-described scalar region and equivalent refractive index region, there is a resonance region in which the diffraction efficiency changes rapidly due to a slight difference in incident conditions. For example, when the groove width of the diffraction ring zone is narrowed, a phenomenon (anomaly) occurs in which the diffraction efficiency rapidly decreases and increases by several times the wavelength. By utilizing the characteristics of this region, a waveguide mode resonance grating filter that reflects only a specific wavelength can be realized with a fine structure, and the same effect as a normal interference filter can be realized with less angular dependence.

  By the way, when an optical element is formed using a scalar region, an equivalent refractive index region, a resonance region, or the like, it is necessary to form fine protrusions (or depressions) on the optical surface. In order to mass-produce optical elements having such fine protrusions (or dents), it can be said that it is generally suitable to perform molding using a resin as a raw material. The problem is how to form an optical surface transfer surface having a depression (or protrusion) corresponding to the depression.

  That is, for the projections (or depressions) in the equivalent refractive region and the resonance region as described above, the projections (or depressions) must be formed on the optical surface of the optical element at intervals of several tens to several hundreds of nanometers. In conventional injection molding, the resin does not reach the depth of the fine shape of the mold corresponding to it, and it is extremely difficult to accurately transfer the fine shape.

  On the other hand, the temperature of the mold having a fine shape is set higher than the glass transition temperature of a material having an elastic modulus of 1 to 4 (GPa) at room temperature, for example, and the mold is pressed toward the resin material. Therefore, the present inventors have studied a technique capable of transferring the fine shape to a resin material and thereby enabling accurate transfer molding even if the fine shape has a high aspect ratio. However, even if transfer of a fine shape is possible by the above-described technique, there is a problem that the material and the mold are easily stuck when being released, and molding is difficult.

  The present invention has been made in view of such problems of the prior art, and can be applied to a water repellent treatment method, a water repellent treatment mold, a regeneration method thereof, a regeneration device, and a molding, which can be performed easily and at low cost. It is an object to provide a method, a molding apparatus, and an optical element.

The processing method of the first aspect of the present invention is a processing method of a mold made of silicon that is molded by being pressed against the surface of a resin material, and uses fluorine in a fluorine-based gas containing oxygen gas on the surface of the mold. After fixing the mold, the mold is exposed to water vapor so that the surface of the mold can be uniformly coated with fluorine.

  It is preferable to clean the surface of the mold before the molding.

  It is preferable to create a surface shape of the mold using a dry etching apparatus before the molding. In such a case, it is convenient to perform a fluorine coating simultaneously with the formation of a fine shape by performing a dry etching process using a fluorine gas.

The mold made of silicon that is molded by pressing against the surface of the resin material is preferably treated by the above-described treatment method.

The mold made of silicon to be molded by pressing against the surface of the resin material is preferably processed by the above-described processing method and has a shape in which the aspect ratio of the surface shape of the mold is 1 or more.

  Prior to the present invention, the present inventors have devised a novel method capable of forming a molded product having a fine shape from a completely different viewpoint. For example, in the case of a resin material having an elastic modulus of 1 to 4 (GPa) at room temperature, when a mold having a fine shape is heated and pressed against the mold surface, the pressed surface melts to follow the fine shape. As a result, it has been found that even if the aspect ratio is 1 or more, it is possible to obtain a molded product accurately transferring the fine shape of the mold. In such a case, as described in Patent Document 1, a pressing force of 3000 N is unnecessary, it is sufficient to improve the conventional injection molding machine, the manufacturing equipment is reduced in cost, and a large amount of molding is performed in a short time. It becomes possible to manufacture a thing.

  However, such a molding technique has a problem that the pressed mold and the material stick to each other. On the other hand, if the mold is coated with fluorine, the releasability from the resin material can be improved. However, even if a mold with a fine shape is immersed in a fluorine-based solution or sprayed with the solution, it is difficult to coat with fluorine up to the depth of a submicron-order fine shape, and sufficient mold release properties In addition, there is a risk that the fine shape formed with high accuracy may be damaged by dipping or spraying in the subsequent process.

  Therefore, as a result of diligent research, the inventors of the present invention can perform fluorine coating uniformly on the surface of a fine shape at the same time as fine shape processing if dry etching is performed in an atmosphere of a fluorine-based gas. It was discovered that it was possible to improve the releasability of the resin material. In this specification, “fluorine coat” means that a substance containing fluorine molecules is fixed on the surface. For example, “a type coated with fluorine” means that a substance containing fluorine molecules is fixed on the surface. It shall be a type.

  Incidentally, materials having an elastic modulus of 1 to 4 (GPa) at room temperature include, for example, PMMA (elastic modulus of 1.5 to 3.3 GPa), polycarbonate (elastic modulus of 3.1 GPa), polyolefin (elastic modulus of 2). It is preferable to contain, as a composition component, a resin having an elastic modulus in the range of 1 to 4 such as .5 to 3.1 GPa). Here, room temperature means 25 ° C. These resins preferably have a glass transition point of 50 to 160 ° C. The elastic modulus can be obtained according to JIS-K7161, 7162, and the like. The glass transition temperature can be determined according to JIS R3102-3: 2001.

  In conventional injection molding, since it is difficult for the resin to penetrate deep into the microstructure of the mold corresponding to the diffractive structure, the resulting diffractive structure of the optical element has a sagging corner in the cross section in the optical axis direction and its curvature. The radius greatly exceeds 1 μm, and the light transmittance may be deteriorated. On the other hand, in the optical element of the present invention, the radius of curvature of the corner in the cross section in the optical axis direction of the diffractive structure is less than 1 μm, and higher light transmittance can be obtained. Such a molded product or optical element can be obtained by the following molding method or molding apparatus.

  As shown in FIGS. 1A and 1B, the “aspect ratio” is represented by B / A, where A is the width of the concave or convex portion of the microstructure and B is the depth or height. Value. “Fine shape” means a shape having a value of A of 10 μm or less. The thickness after molding refers to the thickness of the molded product in the direction in which the mold is pressed, and is, for example, the value of T shown in FIG. The thickness after this molding is 0.1 to 20 mm, preferably 1 to 5 mm.

The regeneration method according to the second aspect of the present invention is a regeneration method for regenerating the mold after molding a resin material using a mold in which a fine shape having a fluorine coating to the back of the fine shape is formed. Cleaning the substrate, placing the mold in a first atmosphere made of oxygen gas, generating plasma in the first atmosphere, and forming the mold in a second atmosphere made of fluorine-based gas and oxygen gas And the step of generating plasma in the second atmosphere.

Further, the mold is formed of silicon, and has a step of exposing the surface of the processing object exposed to the plasma to water vapor after generating the plasma in the second atmosphere.

  FIG. 12 is a diagram for explaining the concept of the present invention. In FIG. 12A, the resin material R is molded using a mold M in which a fine shape having a fluorine coating is formed deeply by the above-described dry etching process or the like. Such molding may be normal injection molding, but if the mold M is heated and pressed as described later, the fine shape of the mold M can be transferred to the resin material M with high accuracy.

  However, since the mold M has a fine shape, there is a possibility that the residue of the resin material will remain clogged after forming. Therefore, as shown in FIG. 12B, the mold M is transported to an oxygen gas plasma tank, and the surface thereof is exposed (cleaned) to plasma generated in a (first) atmosphere of oxygen gas. Thereby, the resin material clogged with a fine shape can be removed.

  Subsequently, as shown in FIG. 12C, the mold M is transferred to a fluorine gas + oxygen gas plasma tank, and the surface thereof is exposed to plasma generated in a (second) atmosphere of fluorine gas and oxygen gas. . Thereby, the fluorine coating is applied to the back of the fine shape, and the mold releasability of the mold M can be secured.

  Furthermore, as shown in FIG. 12 (d), high water repellency can be secured in a short time by conveying the mold M to the water tank and exposing the surface to water vapor. Specifically, there are a method in which the inside of the water tank containing the mold M is depressurized and water is vaporized in the tank, and a method in which the mold M is heated with water on a hot plate and exposed to water vapor. The mold M thus regenerated (removing the resin and recoating with fluorine) is used again for molding as shown in FIG.

A reproducing apparatus according to a third aspect of the present invention is a reproducing apparatus that regenerates the mold after molding a resin material using a mold rotating in one direction in which a fine shape formed with a fluorine coating to the back of the fine shape is formed. An apparatus for cleaning the mold, an ashing apparatus for exposing the surface of the mold to a first atmosphere made of oxygen gas at a first rotational position, and generating plasma in the first atmosphere; The surface of the mold is disposed in a second atmosphere composed of a fluorine-based gas and an oxygen gas at a second rotational position after the rotational direction from the first rotational position, and plasma is generated in the second atmosphere. And a coating apparatus.

Further, the mold is formed of silicon, and has a water adding device that exposes the surface of the mold to water vapor at a third rotational position after the second rotational position and in a rotational direction.

  FIG. 13 is a diagram for explaining the concept of the present invention. In FIG. 13, a cylindrical mold M in which a fine shape is formed on the outer peripheral surface by fluorine coating to the back by the dry etching process described above, and a thin plate-shaped resin material R is sandwiched between the opposing rollers RL. ing. The resin material R is unwound from the left roll, and when passing between the rotating mold M and the counter roller RL, the fine shape of the mold M is continuously transferred, and further rolled to the right. It is designed to be wound up.

  Since the outer peripheral surface of the mold M has a fine shape, there is a possibility that the residue of the resin material will remain clogged after forming. Therefore, as shown in the figure, the outer peripheral surface after the molding of the mold M is first rotationally moved to the ashing device (cleaning device) in the first position, and is generated in the (first) atmosphere of oxygen gas. Exposed to plasma. Thereby, the resin material clogged with a fine shape can be removed.

  Subsequently, the outer peripheral surface of the mold M that has passed through the ashing device rotates and moves to the coating device at the second position, and is exposed to the plasma generated in the (second) atmosphere of fluorine gas and oxygen gas. It is like that. Thereby, the fluorine coating is applied to the back of the fine shape, and the mold releasability of the mold M can be secured.

  Further, the outer peripheral surface of the mold M that has passed through the coating apparatus is rotationally moved to the water adding apparatus at the third position, and is subjected to surface treatment by being exposed to water vapor. In this way, the outer peripheral surface of the regenerated mold M is moved to the position facing the opposing roller RL again by rotational movement, and a new resin material R can be molded. Can be performed continuously.

  ADVANTAGE OF THE INVENTION According to this invention, the type | mold, the shaping | molding method, a shaping | molding apparatus, and an optical element which can shape | mold the molding which has a microstructure with a small high aspect ratio or small angle R more easily and low-cost can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a flowchart showing the mold manufacturing method according to the present embodiment. FIG. 3 is a cross-sectional view showing a mold material to be processed in the main steps shown in FIG. In the mold manufactured according to the present embodiment, a fine shape corresponding to the diffraction zone of the optical element is formed on the transfer optical surface.

First, in step S101 of FIG. 1, rough processing is performed on the surface of a mold material 10 having a substantially hemispherical shape made of SiO ₂ or polysilicon. After that, in step S102, the mold material 10 is attached to the chuck of a lathe, which will be described in detail later (including an ultra-precision lathe (SPDT machine) here). Further, in step S103, since the mold material 10 is not rotated, the upper surface thereof is cut with a diamond tool as shown in FIG. 3A to correspond to the transfer optical surface (the optical curved surface of the optical element to be molded). 10a), the peripheral groove 11a (first mark) is cut on the upper surface near the outer periphery, and the outer peripheral surface 10f is further cut. At this time, the position of the optical axis of the transfer optical surface 10a cannot be confirmed from its outer shape, but since it is processed at the same time, the transfer optical surface 10a and the circumferential groove 11a are formed coaxially with high accuracy. The outer peripheral surface 10f of the electrode member 11 formed on the cylindrical surface is also formed coaxially with the optical axis with high accuracy. That is, the outer peripheral surface 10f has a rotation axis, which coincides with the optical axis of the transfer optical surface.

  Here, the circumferential groove 11a may be formed of, for example, a plurality of grooves including a dark field portion (corresponding to a concave portion) and a bright field portion (corresponding to a convex portion). It is more preferable to have one (this can be easily formed if the tip of the diamond tool has irregularities). Further, the uneven shape of the circumferential groove 11a can function as a dike for preventing resist scattering applied as will be described later.

  Further, in step S104, the mold material 10 is removed from the ultra-precision lathe, and in step S105, it is set on a stage of a FIB (Focused Ion Beam) processing machine to be described later. In subsequent step S106, the circumferential groove 11a in the mold material 10 on the stage of the FIB processing machine is read, for example, the position of the optical axis of the mold material 10 is determined from its inner edge, and in step S107, the determined optical axis is determined. Three (or four or more) second marks 11b at equal distances are drawn on the mold material 10 (see FIG. 3B). Since the circumferential groove 11a formed by processing with a diamond tool is relatively wide, using this as a reference for processing may reduce processing accuracy. However, the FIB processing machine uses a line with a width of 20 nm. For example, if a crosshair is formed, a fine mark of 20 nm × 20 nm can be formed. By using the mark as a processing reference, higher-precision processing can be expected.

  In step S108, the mold material 10 is removed from the stage of the FIB processing machine, and in step S109, the protective tape 13 is pasted on the second mark 11b (see FIG. 3B). This protective tape 13 is for preventing the resist L applied on the base material 10 in the post-processing from adhering to the second mark 11b. If the resist L adheres to the second mark 11b, reading may be inappropriate as a processing reference.

  Further, in step S110, the mold material 10 is set on a spin coater (not shown), and in step S111, a press pin is performed while the resist L is allowed to flow onto the mold material 10, and then this spin is performed in step S112. Then, a resist L film is formed (see FIG. 3B). The reason why the press pin and the main spin are separated is that the transfer optical surface 10a, which is a complicated curved surface, is coated with a resist L having a uniform film thickness.

  Thereafter, in step S113, the mold material 10 is removed from the spin coater, and in step S114, baking is performed to stabilize the coating of the resist L. In step S115, the protective tape 13 is peeled off.

  Subsequently, in step S116, the mold material 10 is set in a shape measuring device (not shown) (having an image recognition means and a storage means), and in step S117, the second shape is measured using the image recognition means of the shape measuring device. The mark 11b is detected. Further, in step S118, the three-dimensional coordinates of the transfer optical surface 10a of the mold material 10 used in the ultra-precision lathe are converted into three-dimensional coordinates based on the second mark 11b and stored in the storage means. In this way, the transfer optical surface 10a is re-stored in the new three-dimensional coordinates because the focal depth of the narrow electron beam with respect to the processing surface of the transfer optical surface 10a when performing electron beam drawing in a later process. This is because it is necessary to adjust the relative position between the electron gun and the mold material 10 in order to match the two. Note that the second mark 11b can be used as a position recognition mark for an operator to visually recognize the reference point of coordinates related to measurement data during measurement. Thereafter, in step S119, the mold material 10 is removed from the shape measuring instrument.

  In step S120, the mold material 10 is set on a three-dimensional stage of an electron beam drawing apparatus to be described later. In step S121, the reading material (scanning electron microscope: preferably attached to the electron beam drawing apparatus) is used. The second mark 11b of the mold material 10 is detected, and the shape of the processed surface of the transfer optical surface 10a is obtained from the stored three-dimensional coordinates of the transfer optical surface 10a, and obtained in step S122. The three-dimensional stage is moved so that the electron beam is focused on the shape of the surface to be processed, the electron beam B (see FIG. 3B) is irradiated, and a desired annular zone shape is drawn as a predetermined process. To do. After drawing, in step S123, the mold material 10 is removed from the three-dimensional stage, and development processing is performed in step S124 to obtain a ring-shaped resist. Here, if the irradiation time of the electron beam B at the same point is lengthened, the resist removal amount increases accordingly. Therefore, by adjusting the position and the irradiation time (dose amount), a blazed annular zone is obtained. Resist can be left. Note that a brace-shaped ring zone may be formed on the transfer optical surface as described later by obtaining a ring-shaped resist as described above with reference to the outer peripheral surface 10f of the mold material 10.

In step S125, the resist is removed through dry etching by plasma shower (p), and the surface of the transfer optical surface 10a of the mold material 10 is further engraved to form a blazed ring zone 10b (exaggerated from the actual state). (See FIG. 3C). At this time, by performing dry etching in an atmosphere of fluorine-based gas (SF ₆ , CF _4, etc.), a uniform fluorine coat can be applied to the surface simultaneously with the formation of a fine shape. If dry etching is performed using a gas other than fluorine-based gas, the same uniform fluorine coating can be achieved by generating plasma by filling the atmosphere with fluorine-based gas without opening the atmosphere to the atmosphere. In this way, the mold 10 having a fine shape is formed.

  According to the present embodiment, by applying a fluorine coating to the mold material by using a dry etching apparatus, the coating can be performed while eliminating the intrusion of foreign matters in a vacuum. Etc. In addition, since a fluorine solution or the like is not used, handling is easy, processing is not required, material costs can be reduced, and it is preferable from the viewpoint of environmental protection. Also, if the groove width is 1 μm or less, it is difficult to coat uniformly to the groove bottom due to the surface tension of the liquid when immersed or sprayed with a fluorine-based solution. By reducing plasma generation in the atmosphere, uniform fluorine coating can be achieved up to the bottom of the fine shape.

  According to the experimental results of the present inventors, the contact angle of water droplets when pure water was dropped on a silicon substrate was 39 degrees, whereas the silicon substrate was immersed in a fluorine-based solution. The contact angle of water droplets in the comparative example in which the surface was coated with fluorine was about 100 degrees. On the other hand, by generating plasma in an atmosphere of fluorine-based gas holding a silicon base material, the contact angle of water droplets in the embodiment in which the surface is fluorine-coated is about 100 degrees, which is the same as when immersed. Water repellent effect was observed.

  FIG. 14 is a diagram showing the results of XPS analysis performed by the present inventors. According to the XPS analysis result, as shown in FIG. 14, the fluorine element was measured in the state where the incident angle of X-ray was changed from 30 degrees to 90 degrees. The amount of fluorine element was larger in the whole area. That is, it can be seen that the fluorine coating was performed uniformly regardless of the location.

  FIG. 15 is a diagram showing the experimental effect of the water treatment performed by the present inventors. According to such experimental results, when the treated surface of the silicon base material is not exposed to water vapor after dry etching, it takes 6 hours or more to obtain a predetermined water repellency, whereas it is exposed to water vapor. It was found that it took less than a few minutes to obtain the same water repellency.

  FIG. 4 is a cross-sectional view of an optical element molding apparatus capable of performing the molding method according to the present embodiment. In FIG. 4, a circular upper die 2 is movably disposed on the lower die 1. A cylindrical movable mold 3 is included so as to be slidable with respect to the upper mold 2, and a movable mold 10 manufactured by the manufacturing method of FIGS. Has been.

  On the lower surface of the movable mold 3, an aspherical shape 3a of the optical element to be molded and a fine shape 3b corresponding to a shape causing structural birefringence are formed. A heater 4 is installed inside the movable mold 3. On the upper surface of the movable mold 10, an aspherical shape 10a of the optical element to be molded and a fine shape 10b corresponding to the diffractive structure are formed. A heater 4 ′ is installed inside the movable mold 10. In the present embodiment, the lower mold 1 and the upper mold 2 constitute a fixed mold.

  FIG. 5 is a flowchart showing the molding method according to the present embodiment. Such a molding method will be described with reference to FIG. First, in step S201, the lower mold 1, the upper mold 2, the movable molds 3 and 10 are arranged in the state shown in FIG. 4, and so-called mold clamping is performed. Subsequently, in step S202, the resin material heated and melted by an external heating cylinder (not shown) is injected into the lower mold 1 and the upper mold 2 through the gate G (step of injecting the material).

  In step S203, the injected material is cooled (either natural cooling or forced cooling in which at least one of the movable molds 3 and 10 is retracted to expose the material to the atmosphere). At this time, the aspherical shapes 3a and 10b of the movable molds 3 and 10 are transferred to the surface of the material. However, it is difficult to sufficiently transfer the fine shapes 3b and 10b only by injection of the material. Therefore, in step S204, the movable molds 3 and 10 are heated by the heaters 4 and 4 'so that the temperature is equal to or higher than the glass transition point of the resin material (step of setting the mold temperature higher than the glass transition temperature of the material). Thereafter, in step S205, when the movable molds 3 and 10 are pressed toward the resin material with a slight force (the movable mold 3 on the upper side in the direction of gravity may have its own weight) by a driving unit (not shown), the fine shapes 3b and 10b are formed. The surface of the corresponding resin material melts and reaches the groove bottoms of the fine shapes 3b and 10b (step of transferring the fine shape). Therefore, even a fine shape having an aspect ratio of 1 or more and a fine shape having a radius of curvature of a corner of the cross section in the optical axis direction of 1 μm or less can be accurately transferred.

  Thereafter, in step S206, heating of the heaters 4 and 4 ′ is stopped, and the resin material is cooled and solidified (cooling step). In step S207, the lower mold 1 and the upper mold 2 are moved using the driving unit (not shown). By opening the molds 3 and 10 to retract, an optical element that obtains a highly accurate fine shape can be formed. At this time, since the surfaces of the aspherical shapes 3a and 10a and the fine shapes 3b and 10b are uniformly coated with fluorine, it is possible to prevent the resin material from sticking when the mold is opened.

  In the conventional injection molding, a cycle time of about several tens of seconds is required when the fine shape is not transferred, and about one minute is required when the fine shape is transferred, but according to the molding method of the present invention, In the case where the fine shape is transferred to the surface of the workpiece that has been previously molded within the design shape error range and the shape is shaped, the molding is completed in a cycle time of 2 to 3 seconds. Also, even when starting from the step of injecting the molding material, when transferring the fine shape and shaping the shape, it is difficult with the prior art, just adding a process of +2 to 3 seconds to the conventional injection molding The fine shape can be accurately and reliably transferred within an error of several nm.

  FIG. 6 is a diagram showing an example of an optical element molded by the above molding method. The optical element 15 having the shape shown in the perspective view of FIG. 6 (a) has a fine shape 15a of structural birefringence on the surface as shown in FIG. 6 (b). As shown, the back surface has a diffractive structure 15b having a sawtooth cross section in the optical axis direction. The fine shape 15a of structural birefringence has a ring-shaped rectangular groove, and has a cross-sectional shape shown in FIG. Here, as an example, if the refractive index of the material of the optical element 15 is 1.92 and the wavelength of incident light is λ, the dimensions of each part in the fine shape 15a of structural birefringence are d1 = 0.25λ, d2 (Groove width) = 0.39λ, d3 = 2λ, d4 (groove depth) = 1.22λ. In FIG. 6C, the radius of curvature R of the corner portion in the cross section in the optical axis direction of the sawtooth diffraction structure 15b is less than 1 μm.

  FIG. 7 is a diagram showing another example of an optical element molded by the above molding method. The optical element 20 having the shape shown in the cross-sectional view of FIG. 7A has a diffractive structure 20a having a serrated cross section in the optical axis direction on the surface, as shown in FIG. 7B. Furthermore, a large number of conical holes 20b having a diameter reduced in the depth direction are formed on the inclined surface of the diffractive structure 20a. The hole 20b having the antireflection function occupies 20% to 40% (preferably 30%) of the area of the inclined surface.

(Ultra-precision lathe: SPDT processing equipment)
Hereinafter, a schematic configuration of a control system of an ultra-precision lathe used for cutting the mold material 10, for example, SPDT (Single Point Diamond Turning), will be described with reference to FIGS. 8A and 8B.

  As shown in FIG. 8A, the ultra-precision lathe 100 is provided with a fixed portion 111 that is a rotation holding member for fixing a workpiece 110 such as a mold material 10 and the workpiece 110 for processing. The diamond tool 112 that is the cutting edge of the cutting tool, the Z-axis slide table 120 that moves the fixed portion 111 in the Z-axis direction, and the X-axis direction (or in addition to the Y-axis direction) while holding the diamond tool 112 The X-axis slide table 122 to be moved, and the surface plate 124 that holds the Z-axis slide table 120 and the X-axis slide table 122 movably are configured. In addition, a rotation drive unit (not shown) for rotating and driving either one or both of the fixed portion 111 and the diamond tool 112 is provided, and is electrically connected to a control unit 138 described later.

  Further, as shown in FIG. 8A, the ultra-precision lathe 100 is driven (or added) in the X-axis direction by the Z-direction drive means 131 for controlling the drive of the Z-axis slide table 120 and the X-axis slide table 122. X-direction drive means 132 and Y-direction drive means 133 for controlling the drive in the Y-axis direction, feed amount control means 134 for controlling the feed amount by these, and cut amount control means 135 for controlling the cut amount. And a temperature control means 136 for controlling the temperature, a storage means 137 for storing various control conditions and control tables or processing programs, and a control means 138 for controlling these parts.

  As shown in FIG. 8 (b), the diamond tool 112 includes a diamond tip 113 constituting the main body portion, a rake face 114 composed of the apex angle α formed at the tip portion, and a first relief constituting the side surface portion. It comprises a surface 115 and a second flank 116. On the cutting edge included in the rake face 114, a plurality of uneven portions 114a are formed in advance or due to wear.

  The ultra-precision lathe 100 having the above-described configuration operates as follows in general. That is, the workpiece 110 is processed by the relative movement of the diamond tool 112 with respect to the workpiece 110 that is the set material 10. At this time, since the cutting edge of the diamond tool 112 has an R bite configuration, the point on which the cutting edge strikes sequentially changes and is resistant to wear.

  And in this Embodiment, when processing the raw material 10 of the said mold | die using the above ultra-precision lathes, while controlling temperature, controlling the feed amount and the cutting amount, the curved surface The part will be cut.

(About focused ion beam (FIB) processing equipment)
Next, a schematic configuration of the focused ion beam processing apparatus for forming the second mark 11b will be described with reference to FIG.

  A focused ion beam processing apparatus (FIB) is a scan obtained by processing a mold material 10 with a focused ion beam using a metal ion source such as Ga or scanning a focused ion beam onto the mold material 10. Image observation (SIM: Scanning Ion Microscope) is performed, and an ion beam generated from an ion source and accelerated is finely focused by an electrostatic condenser lens, an objective lens or the like, and irradiated onto a mold material 10. The ion beam irradiation point on the mold material 10 is scanned by a deflector, and, for example, secondary electrons generated from the mold material 10 are detected by this scanning. Based on this detection signal, a scanned image or the like is detected. To display.

  The focused ion beam processing apparatus 200 is maintained in a high vacuum. As shown in FIG. 9, a liquid metal ion source 201 serving as an ion source, an extraction electrode 202 that extracts ions, and a plurality of ions that accelerate the ion beam to a desired energy. Accelerating tube 203 composed of stages, condenser lens 204 whose aperture can be varied by an aperture 205 for limiting the ion beam, objective lens 206 whose aperture can be variably adjusted by an aperture 207, and which focuses the ion beam and irradiates the sample, deflector 208, E × B mass analyzer 209 with blanking / E × B restriction aperture, emitter alignment 210, alignment set stigmator 211, alignment set 212, alignment set stigmator 213, and material 10 of the mold to be processed Placed mold material 10 A stage 214 whose position and inclination can be freely adjusted, a detector 215 for detecting a position recognition mark and the like, a laser interferometer 217 including a laser supply source 216 and an optical system, a stage driving means 220 for driving the stage 214, and these And a control circuit 230 for controlling each part of the apparatus, an operation input unit 261 for performing operation input, an image recognition unit 260 for observing and recognizing the mold material 10 and the scanned image, a power source (not shown), and the like. .

  The apertures 205 and 207 have openings that can change the diameter of the ion beam, for example, by restricting the path of the ion beam, and have a thickness that allows the ion beam to pass through other than the openings. . The aperture may be formed in N stages.

  The detector 215 is for detecting, for example, secondary electrons generated based on the irradiation of the ion beam onto the mold material 10.

  The stage driving means 220 includes an X direction driving mechanism 221 for driving the stage in the X direction, a Y direction driving mechanism for driving in the Y direction, a Z direction driving mechanism for driving in the Z direction, and a θ direction. And a θ-direction drive mechanism for driving the motor.

  The control circuit 230 includes an ion source control circuit 231 that controls the ion source 201, an acceleration tube control circuit 232 that controls the acceleration tube 203, a first focusing control circuit 233 that controls focusing by the condenser lens 204, and an objective lens. Generated by a second focusing control circuit 234 for controlling focusing by 206, a deflection control circuit 235 for controlling the deflector of the deflector 208, a stage control circuit 236 for controlling the stage driving means 220, and the mold material 10. By controlling a detector control circuit 237 that controls signal processing from the detector 21 that detects secondary ions, a laser interferometer control circuit 238 that controls the laser interferometer 217, and the E × B mass analyzer 209. Ion selection control circuit 239 for selecting ions, emitter alignment 210 and alignment set stigmator 21 The first to fourth alignment control circuits 240, 241, 242, and 243 for controlling the alignment set 212 and the alignment set stigmator 213, various control tables, a storage unit 250 that stores a program, and various display images A display processing unit 251 that performs display processing and a control unit 252 such as a CPU that controls these operations are included.

  The storage unit 250 is realized as an area of a storage device such as a semiconductor memory or a disk device, and stores a combination of image data and position data. For example, a combination of position data including cross-section position coordinates and cross-sectional image data in which the pixels constituting each cross-sectional image data are stored in the scanning order can be stored as a pair of data. The storage unit 250 is provided with a plurality of areas for storing the data, and stores the data corresponding to the cross sections formed at specific positions of the mold material 10 in, for example, the order of the position data. it can.

  The display processing unit 251 performs processing so as to display, for example, an image or the like on the image recognition unit 260 based on each image data and position data stored in the storage unit 250 in order to display a specific location. The display processing unit 251 can read pixel data of arbitrary X, Y, and Z coordinates from the data stored in the storage unit 250 and display a stereoscopic image viewed from a desired viewpoint on the image recognition unit 260. It is good. Various display methods can be considered. For example, a contour is extracted from adjacent pixel data, and the front-rear relation of the contour is determined so that a hidden portion can be displayed with a broken line or the like. It is preferable. Also, the image data is subjected to image processing such as contour extraction based on changes in brightness, and the size and position of characteristic portions of the surface of the mold material 10 such as holes and lines formed by ion beams are recognized. Then, the stage 214 can determine whether or not the mold material 10 is arranged at a desired position and whether or not holes and lines of a desired size are formed in the mold material 10 by the ion beam. It's okay.

  The control unit 252 receives a detection signal from the detector 215 via, for example, the detector control circuit 237, forms image data, and sets each unit based on an instruction from the operation input unit 261 or image data. Set various conditions. Further, the stage 214 and each unit for ion beam irradiation can be controlled in accordance with an operator instruction input from the operation input unit 261 or the like.

  The control unit 252 receives all detection signals from the detector 215 converted into digital values by the detector control circuit 237. The detection signal changes according to the position where the ion beam is scanned, that is, the deflection direction of the ion beam. Therefore, by synchronizing the deflection direction and the detection signal, the surface shape and material of the mold material 10 at each scanning position of the ion beam can be detected. The control unit 252 can reconstruct these corresponding to the scanning positions and display the image data of the surface of the mold material 10 on the image recognition unit 260.

(Description of operation)
In the focused ion beam apparatus 200 having the configuration as described above, first, a material 10 of a type in which the transfer optical surface 10 and the first mark 11b are formed on one surface on a stage 214 provided in the focused ion beam apparatus 200. The focused ion beam apparatus 200 is set up so that the surroundings are in a vacuum state and the ion beam can be scanned onto the mold material 10.

  Next, a certain area on the mold material 10 is scanned with an ion beam. At this time, ions from the ion source 201 are generated at an extraction voltage of 5 to 10 kV and accelerated by the acceleration tube 203. The accelerated ion beam is focused by the condenser lens 204 and the objective lens 206 and reaches the mold material 10 on the stage 214.

  When an alloy ion source such as Au—Si—Be is used, only necessary ions are moved straight by the E × B mass analyzer 209, and the necessary ions are separated by bending the trajectory of unnecessary ions. You can choose.

  In addition, when handling an ion having an isotope such as Si, it is preferable that the crossover point of the ion beam by the condenser lens 204 is adjusted and controlled so as to be at the center of the E × B mass analyzer 209. . Thereby, it is possible to effectively use isotopes without separating them. In this way, the ions can be focused at one point on the mold material 10 by the objective lens 206 and scanned, for example, in a raster pattern.

  By scanning, secondary electrons and secondary ions emitted from the surface of the mold material 10 are detected, and based on the detection results, image processing is performed by the display processing unit 251 to generate a SIM image indicating the surface shape of the region. The image is displayed on the image recognition unit 260. For example, each time the stage 214 is moved, a SIM image is displayed and the stage 214 is aligned so that a specific location can be displayed.

  For example, the operator may specify, for example, a processing region, a processing time, and an ion beam current value as a processing condition setting for a SIM image displaying a specific location using the operation input unit 261 or the like. . For example, a SIM image of the surface of the mold material 10 is acquired, a processing region is set for a specific location, a processing time of the processing region, an ion beam diameter and an electric current value of an ion beam used for processing, Is specified. The state of the mold material 10 may be observed using another observation optical system (not shown).

  Here, in the present embodiment, the image recognition unit 260 recognizes the first mark 11 a on the mold material 10 based on the detection signal from the detector 215.

  A parallel line parallel to the line of the first mark 11a is formed by an ion beam. At this time, it is preferable to form the parallel lines so as to draw a part of the arc or linearly by the relative movement of the stage 214 and the ion beam.

  At this time, the focused ion beam processing apparatus 200 scans the processing region. The amount of sputtering is determined by the material of the mold material 10, the type of ion beam (difference in ion beam current value), energy, dose amount, etc., so that the processing region is brought to a substantially constant depth by one scan. You can dig up. Corresponding to scanning, all detection signals of secondary electrons and secondary ions are stored in the storage unit 250, image data at a specific location is acquired, and an image at an arbitrary position is obtained in accordance with an operator's instruction. be able to.

  Next, an orthogonal line substantially orthogonal to the parallel line is formed by an ion beam. By forming a plurality of these, for example, three places in the direction along the circumference of the concentric circle of the first mark 11a, a plurality of second marks 11b can be formed.

  Note that the formation procedure when forming the second marks 11b at three locations is not limited to the above, and the parallel lines at the three locations are formed by rotating the stage 214 intermittently in advance. Then, an orthogonal line for each location may be formed.

  Furthermore, these control procedures are stored in advance in the storage unit 250 as a control program, and when the operation input unit 261 forms, for example, three second marks 11b, “3”, 5 When forming the location, by inputting “5”, the first mark 11a is automatically detected and the point where the second mark 11b is to be formed is automatically calculated, and the execution start button or the like is pressed. By doing so, it is preferable that the second mark 11b is automatically formed.

  In this way, using the focused ion beam device, the observation optical system of the focused ion beam device or the secondary ion image is used for observation, the first mark is recognized, and the coordinates are determined at the stage position of the focused ion beam device. know. The second mark can be formed by scanning the focused ion beam at the coordinate position.

  Here, the line width (beam focusing) is preferably about 1 nm to about 50 nm, for example. However, this is limited to the case where Ga ions are implanted. More preferably, it is about 20 nm. This is because the positional deviation of the central axis of the optical element needs to be within 1 μm, and the position can be determined by a sufficiently small diameter with respect to this 1 μm.

  Note that the focused ion beam processing apparatus is not limited to such an example, and processing with an ion beam and surface observation are simultaneously performed, and images of a plane parallel to the surface of the mold material 10 are sequentially acquired to obtain a three-dimensional image. While storing as data, you may have the structure which acquires arbitrary cross sections by image conversion.

(About electron beam lithography system)
Next, the overall schematic configuration of the electron beam drawing apparatus will be described with reference to FIG. FIG. 10 is an explanatory diagram showing the overall configuration of the electron beam lithography apparatus of this example.

  As shown in FIG. 10, the electron beam drawing apparatus 401 forms a high-resolution electron beam probe with a large current and scans the material 10 of the drawing target mold at a high speed. , An electron gun 412 which is an electron beam generating means for generating an electron beam and irradiating the target with a beam, a slit 414 for passing the electron beam from the electron gun 412, and an electron passing through the slit 414 An electron lens 416 for controlling the focal position of the beam with respect to the material 10 of the type, an aperture 418 disposed on the path through which the electron beam is emitted and having a desired electron beam shape by an aperture, and an electron A deflector 420 that controls the scanning position on the target material 10 by deflecting the beam, and a correction coil that corrects the deflection. It is configured to include a 422, a. These parts are arranged in the lens barrel 410 and maintained in a vacuum state when the electron beam is emitted.

  Further, the electron beam drawing apparatus 411 transports the mold material 10 to an XYZ stage 430 which is a mounting table for placing the mold material 10 to be drawn, and a placement position on the XYZ stage 430. A loader 440 as a transport means, a measuring device 480 as a measuring means for measuring the reference point of the surface of the mold material 10 on the XYZ stage 430, and a stage as a driving means for driving the XYZ stage 430 Driving means 450, loader driving device 460 for driving the loader, vacuum exhausting device 470 for exhausting the interior of the lens barrel 410 and the housing 411 including the XYZ stage 430 to be evacuated, and the mold material 10 An observation system 491 for observing the top and a control circuit 492 which is a control means for controlling these operations are included.

  The electronic lens 416 is respectively controlled by generating a plurality of electronic lenses according to the current values of the coils 417a, 417b, and 417c, which are separately provided at a plurality of locations along the height direction. The focal position of the electron beam is controlled.

  The measuring apparatus 480 includes a first laser length measuring device 482 that measures the mold material 10 by irradiating the mold material 10 with a laser, and a laser beam emitted by the first laser length measuring device 482. The first light receiving unit 484 that receives the first reflected light from the mold material 10 and receives the reflected light, and the second laser irradiating from a different irradiation angle from the first laser length measuring device 482. A laser length measuring device 486 and a second light receiving portion 488 that receives the reflected light when the laser light (second irradiation light) emitted by the second laser length measuring device 486 reflects the mold material 10. And.

  The stage driving unit 450 includes an X direction driving mechanism 452 that drives the XYZ stage 430 in the X direction, a Y direction driving mechanism 454 that drives the XYZ stage 430 in the Y direction, and a Z direction driving that drives the XYZ stage 430 in the Z direction. A mechanism 456 and a θ-direction drive mechanism 458 for driving the XYZ stage 430 in the θ direction are configured. As a result, the XYZ stage 430 can be operated three-dimensionally and alignment can be performed.

  Although not shown, the control circuit 492 includes an electron gun power supply unit for supplying power to the electron gun 412, an electron gun control unit for adjusting and controlling current, voltage, and the like in the electron gun power supply unit, an electron lens 416 ( A lens power supply unit for operating each of the plurality of electronic lenses, and a lens control unit for adjusting and controlling each current corresponding to each electronic lens in the lens power supply unit.

  Further, the control circuit 492 includes a coil control unit for controlling the correction coil 422, a shaping deflection unit for deflecting in the molding direction by the deflector 420, and a secondary for performing deflection in the sub-scanning direction by the deflector 420. A deflection unit, a main deflection unit for deflecting in the main scanning direction by the deflector 420, an electric field control circuit that is an electric field control means for controlling the electric field of the electron beam, a drawing pattern, and the like are generated for the material 10 of the type. Pattern generating circuit, various laser control systems, stage control circuit for controlling stage driving means 450, loader control circuit for controlling loader driving device 460, measurement information input unit for inputting measurement information, A memory that is a storage means for storing stored information and a plurality of other information, a program memory that stores a control program for performing various controls, and each unit Your system is configured to include a control unit, which is formed by a CPU for example controls the these units.

(Description of operation)
In the electron beam lithography apparatus 401 having the above-described configuration, when the mold material 10 conveyed by the loader 440 is placed on the XYZ stage 430, the vacuum exhaust device 470 causes the lens barrel 410 and the housing 411 to be in the interior. After exhausting air or dust, an electron beam is irradiated from the electron gun 412.

  The electron beam irradiated from the electron gun 412 is deflected by the deflector 420 via the electron lens 416, and the deflected electron beam B (hereinafter, only with respect to the deflection-controlled electron beam after passing through the electron lens 416) “Electron beam B” may be given a symbol), and drawing is performed by irradiating the drawing position on the surface of the mold material 10 on the XYZ stage 430, for example, the curved surface (curved surface) 12. .

  At this time, the measuring device 480 measures the drawing position on the mold material 10 (at least the height position among the drawing positions) or the position of a reference point as described later, and the control circuit 492 displays the measurement result. Based on this, the current value flowing through the coils 417a, 417b, 417c and the like of the electron lens 416 is adjusted and controlled, and the position of the focal depth of the electron beam B, that is, the focal position is controlled, and the focal position becomes the drawing position. The movement is controlled as follows.

  Alternatively, based on the measurement result, the control circuit 492 moves the XYZ stage 430 so that the focal position of the electron beam B becomes the drawing position by controlling the stage driving unit 450.

  In this example, the control may be performed by either the electron beam control or the XYZ stage 430 control, or by using both.

  Next, the first laser beam length 482 of the measuring device 480 irradiates the mold material 10 with the first light beam S1 from the direction intersecting the electron beam, and transmits the first material beam 10 through the mold material 10. The first light intensity distribution is detected by receiving the light beam S1.

  At this time, since the first light beam S1 is reflected on the bottom of the mold material 10, the (height) position on the flat portion of the mold material 10 is measured and calculated based on the first intensity distribution. Will be. However, in this case, the (height) position of the mold material 10 on the transfer optical surface 10 cannot be measured.

  Therefore, in this example, a second laser length measuring device 486 is further provided. That is, the second laser length measuring device 486 irradiates the mold material 10 with the second light beam S2 from a direction substantially orthogonal to the electron beam different from the first light beam S1, and the mold material 10 The second light beam S2 that is transmitted is received by the second light receiving unit 488, whereby the second light intensity distribution is detected, and based on this, the position is measured and calculated.

  Then, using the height position of the material 10 of this type as a drawing position, for example, the focal position of the electron beam is adjusted and drawing is performed.

(About the configuration of the plasma etching system)
Next, a schematic configuration of a plasma etching apparatus for performing a dry (plasma) etching process on the mold material 10 will be described. As an example of performing anisotropic etching, an inductively coupled plasma processing apparatus capable of generating high-density plasma is shown here.

  In a typical structure of an inductively coupled plasma processing apparatus, a dielectric wall (window plate) is disposed on the ceiling of an airtight processing chamber, and a radio frequency (RF) antenna is disposed on the dielectric wall. An induction electric field is formed in the processing chamber by the high-frequency antenna, and the processing gas is converted into plasma by the electric field. By using the plasma of the processing gas generated in this way, the substrate disposed in the processing chamber is subjected to processing such as etching.

  FIG. 11 is a schematic cross-sectional view showing the inductively coupled plasma etching apparatus according to the present embodiment. As shown in FIG. 11, the plasma etching apparatus 301 includes an airtight container 320 that is assembled so as to be disassembled from a housing made of a conductive material, for example, aluminum. The container 320 is grounded by a ground wire 321. In addition, the inner wall surface of the container 320 is anodized by anodization so that contaminants are not generated from the wall surface.

  It is preferable that the inside of the container 320 be hermetically isolated by the upper antenna chamber 324 and the processing chamber 326. The partition structure partitioned upon isolation is formed by a support portion 334 including a dielectric wall 332 formed by combining segments made of quartz or the like. The lower surface of the support part 334 is formed in a substantially uniform state on a horizontal plane.

  The lower surface of the support portion 334 is preferably further covered with a dielectric cover (not shown) made of quartz or the like having a smooth lower surface. On the other hand, the PTFE (polytetra It is preferable to dispose a resin plate (not shown) made of fluoroethylene) or the like.

  A heater 361 is disposed in the antenna chamber 324 and is connected to a power source 362. The partition structure including the dielectric wall 332 is heated by the heater 361 via the support portion 334, thereby preventing the by-product from adhering to the lower surface of the partition structure exposed to the processing chamber 326.

  The support portion 334 is formed of a hollow member made of a conductive material, preferably a metal, for example, an aluminum housing, and is also used as a shower housing for forming a shower head. The inner and outer surfaces of the casing constituting the support portion 334 are anodized by anodization so that contaminants are not generated from the wall surface. The support / shower housing 334 has a gas flow path formed therein, and a plurality of gas supply holes that communicate with the gas flow path and open to a susceptor, that is, a mounting table 371 described later, are formed on the lower surface. The

  A gas supply pipe 351 communicating with a gas flow path in the support part 334 is disposed in a tubular pipe part 335 connected to the center of the support part 334. The gas supply pipe 351 passes through the ceiling of the container 320 and is connected to the processing gas source unit 350 disposed outside the container 320. That is, during the plasma processing, the processing gas is supplied from the processing gas source unit 350 through the gas supply pipe 351 into the support / shower casing 334 and is released into the processing chamber 326 through the gas supply hole on the lower surface thereof. The

  In the antenna chamber 324, a high frequency (RF) antenna 331 disposed on the partition structure is disposed so as to face the dielectric wall 332.

  The antenna 331 is a planar coil antenna whose part on the partition structure forms, for example, a spiral shape. One end of the antenna 331 is led out from the approximate center of the ceiling of the container 320 and is connected to the high-frequency power source 342 via the matching unit 341. On the other hand, the other end is connected to the container 320 and thereby grounded.

  During the plasma processing, high-frequency power for generating an induction electric field is supplied to the antenna 331 from the high-frequency power source 342. An induction electric field is formed in the processing chamber 326 by the antenna 331, and the processing gas supplied from the supporter / shower casing 334 is converted into plasma by the induction electric field. For this reason, the high frequency power supply 342 is set so that high frequency power can be supplied with an output sufficient to generate plasma.

  A susceptor 371, which is a mounting table for mounting a substrate, is disposed in the processing chamber 326 so as to face the high-frequency antenna 331 with the dielectric wall 332 interposed therebetween. The susceptor 371 is made of a conductive material, for example, an aluminum member, and its surface is anodized by anodization so as not to generate contaminants. A holding member 373 for fixing the base material is disposed around the susceptor 371.

  The susceptor 371 is housed in the insulator frame 372 and further supported on a hollow column. The support column penetrates the bottom of the container 320 in an airtight manner and is supported by driving means 374 disposed outside the container 320. That is, the susceptor 371 is driven, for example, in the vertical direction by the driving means 374 when the mold material 10 is loaded / unloaded.

  The susceptor 371 is connected to a high-frequency power source 382 through a matching unit 381 by a power feeding rod arranged in a hollow column. During the plasma processing, a high frequency power for bias is applied to the susceptor 371 from the high frequency power supply 382. This bias high-frequency power is used to effectively attract ions in the plasma excited in the processing chamber 326 to the substrate.

  Further, in the susceptor 371, a temperature adjusting means 375 and a temperature sensor (not shown) including a heating means such as a heater and a refrigerant flow path are disposed to control the temperature of the base material. It is connected to temperature control means 376 for controlling. Pipes and wirings for these mechanisms and members are all led out of the container 320 through hollow columns.

  A vacuum exhaust mechanism including a vacuum pump and the like is connected to the bottom of the processing chamber 326 through an exhaust pipe 377. The inside of the processing chamber 326 is exhausted by the vacuum exhaust mechanism, and the inside of the processing chamber 326 is set and maintained in a vacuum atmosphere and a predetermined pressure atmosphere during the plasma processing.

  Control means 394 for controlling the supply of bias power is connected to the bias high-frequency power supply 382 for outputting the bias power according to the present embodiment.

  On the other hand, the control means 394 is also connected to a plasma generation high-frequency power source 342 that outputs plasma generation power having a relatively higher frequency than the bias power, and the control means 394 controls the plasma generation power. Is controlled. The control unit 394 further includes a display unit 393 for displaying various setting input values, an operation input unit 392 for performing operation input, a storage storing various tables, various control programs, setting information, and the like. A means 391 is connected. Information including various correction coefficients set and calculated in the electron beam drawing apparatus by connecting the control means 394 and the control circuit of the electron beam drawing apparatus described above to the network through various communication means. Is preferably stored in the storage means 391 so that it can be used for control.

  Next, the case where the plasma etching process is performed on the mold material 10 using the inductively coupled plasma etching apparatus of FIG. 11 will be described.

First, after the mold material 10 is placed on the placement surface of the susceptor 371 by the conveying means through the gate valve 322, the base member is fixed to the susceptor 371 by the holding member 373. Next, a processing gas containing an etching gas (for example, a mixed gas having a mixing ratio of 9: 1, for example, of SF ₆ and O ₂ ) is discharged from the gas supply source 350 into the processing chamber 326, and the processing chamber 326 is connected via the exhaust pipe 377. The inside of the processing chamber 326 is maintained in a predetermined pressure atmosphere by evacuating the inside.

  Next, by applying predetermined high frequency power from the high frequency power source 342 to the antenna 331, a uniform induction electric field is formed in the processing chamber 326 through the partition wall structure. Due to the induction electric field, the processing gas is converted into plasma in the processing chamber 326, and high-density inductively coupled plasma is generated. The ions in the plasma generated in this way are effectively drawn into the mold material 10 by a predetermined high-frequency power applied to the susceptor 371 from the high-frequency power source 382, and the ions having a resist mask pattern are used. A desired etching process is performed on the material 10.

  At this time, under the control of the control means 394, the high frequency power of the first power having a predetermined first frequency is applied from the high frequency power source 342 for plasma generation, and the high frequency power source 382 for bias is passed through the matching unit 381. The high frequency power of the second power, which is the second frequency relatively lower than the first power for plasma generation, is applied intermittently, for example.

  Here, the bias power is controlled by alternately repeating the on cycle in which the bias power is applied and the off cycle in which the bias power is not applied, and the duty (on cycle time / (on cycle time + off cycle time)). Is preferably controlled. Thereby, for example, the ratio (the etched amount of the base layer / the etched amount of the resist layer) at a specific portion of the substrate can be controlled. In order to generate the on / off cycle of the bias power, a special pulse power supply may be used, or the power on / off may be controlled by software.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. The present invention is not limited to an optical element for an optical pickup device, but can also be applied to molding various optical elements or an inkjet printer head.

It is a figure for demonstrating an aspect-ratio. It is a flowchart figure which shows the manufacturing method of the type | mold concerning this Embodiment. It is sectional drawing which shows the raw material of the type | mold processed in the main processes shown in FIG. It is sectional drawing of the shaping | molding apparatus of the optical element which can implement the shaping | molding method concerning this Embodiment. It is a flowchart figure which shows the shaping | molding method concerning this Embodiment. It is a figure which shows the example of the optical element shape | molded by the shaping | molding method concerning this Embodiment. It is a figure which shows another example of the optical element shape | molded by the shaping | molding method concerning this Embodiment. FIG. 8A is a schematic configuration diagram showing an example of the configuration of an ultra-precision lathe used for machining the member A, and FIG. 8B is a diamond used in the ultra-precision lathe of FIG. 8A. It is a perspective view which shows an example of the blade edge | tip of a tool. It is explanatory drawing which shows an example of a structure of the focused ion beam processing apparatus used for the process of the member A. It is explanatory drawing which shows an example of a structure of an electron beam drawing apparatus. It is a schematic block diagram which shows a plasma etching apparatus. It is a figure for demonstrating the concept of this invention. It is a figure for demonstrating the concept of this invention. It is a figure which shows the experimental result which the present inventors conducted. It is a figure which shows the experimental result which the present inventors conducted.

Explanation of symbols

1 Lower mold 2 Upper mold 3 Movable mold 4 Heater 10 Mold material 11a First mark (circumferential groove)
11b Second mark 100 Super-precision lathe (SPDT processing equipment)
200 focused ion beam processing apparatus 301 plasma etching apparatus 401 electron beam drawing apparatus

Claims (9)

In the processing method of the mold made of silicon that is molded by pressing against the resin material surface,
A treatment method characterized in that after the fluorine atoms are fixed using plasma in a fluorine-based gas containing oxygen gas on the mold surface, the mold is exposed to water vapor . The method according to claim 1, characterized in that prior to the forming, cleaning the mold surface. The processing method according to claim 1 or 2 , wherein the surface shape of the mold is created using a dry etching apparatus before the molding. Type, characterized by being processed by the processing method according to claim 1 or 2. A mold having a shape which is processed by the processing method according to claim 3 and has an aspect ratio of 1 or more of the surface shape of the mold. A recycling method for regenerating the mold after molding a resin material using a mold in which a fine shape formed with a fluorine coat to the back of the fine shape is formed,
Washing the mold;
Placing the mold in a first atmosphere of oxygen gas and generating plasma in the first atmosphere;
And disposing the mold in a second atmosphere comprising a fluorine-based gas and an oxygen gas, and generating plasma in the second atmosphere. 7. The method according to claim 6 , wherein the mold is formed of silicon, and after the plasma is generated in the second atmosphere, the surface of the processing object exposed to the plasma is exposed to water vapor. The playback method described. A recycling apparatus that regenerates the mold after molding a resin material using a mold that rotates in one direction in which a fine shape formed with a fluorine coat to the back of the fine shape is formed,
An apparatus for cleaning the mold;
An ashing device for exposing the surface of the mold to a first atmosphere of oxygen gas at a first rotational position and generating plasma in the first atmosphere;
The mold surface is placed in a second atmosphere composed of a fluorine-based gas and an oxygen gas at a second rotational position after the rotational direction from the first rotational position, and plasma is generated in the second atmosphere. And a coating apparatus for performing the reproduction. 9. The mold according to claim 8 , wherein the mold is made of silicon, and has a hydration device that exposes the surface of the mold to water vapor at a third rotational position after the second rotational position and after the rotational direction. The reproducing apparatus as described.

Images