JP5380904B2 - Optical element, Nippon disk, confocal optical system, and three-dimensional measuring apparatus - Google Patents

Description

  The present invention relates to an optical element having at least a part of light-shielding properties and low reflection characteristics, a manufacturing method thereof, a Nippon disk using the optical element, a confocal optical system using the Nippon disk, and a three-dimensional measuring apparatus. Is.

  2. Description of the Related Art Conventionally, there has been provided an optical element in which a fine concavo-convex structure including a large number of fine protrusions is formed on the surface of a silicon layer on a substrate such as a quartz substrate (Patent Document 1 below). In this optical element, no film or the like is formed on the surface of the substrate opposite to the silicon layer, and the surface is exposed to the outside. In this optical element, light enters from the side of the fine concavo-convex structure. According to this optical element, light is shielded by the fine concavo-convex structure, the reflectance is reduced, and reflection noise is reduced. Therefore, this optical element can be used as, for example, a mask with little reflection noise. Patent Document 1 includes a Nippon disk as an example of such an optical element, and further discloses a confocal optical system and a three-dimensional measuring apparatus using the Nippon disk.

  Further, in Patent Document 1, when manufacturing such an optical element, the surface of the silicon layer is randomly etched on the surface of the silicon layer by dry etching the surface of the silicon layer while depositing a fine mask material on the surface of the silicon layer. It is disclosed to form a fine concavo-convex structure including a large number of fine protrusions distributed in the region.

  Furthermore, Patent Document 1 discloses an example in which a planar chromium layer is formed between the substrate and the silicon layer in the optical element as described above.

Patent Document 2 below discloses an optical element in which a fine concavo-convex structure including a large number of randomly distributed fine protrusions is formed on the surface of a quartz glass substrate. This fine concavo-convex structure is made of quartz glass and functions as an antireflection layer of a transmissive optical element.
International Publication No. 2006/046502 Pamphlet JP 2005-99707 A

  In the case of an optical element having a fine concavo-convex structure formed on the surface of a silicon layer, light having a wavelength longer than about 620 nm, where the transmittance of the silicon layer increases, reduces the light absorption characteristics of the silicon layer, and incident light that has entered the silicon layer. Reaches the interface between the silicon layer and the quartz glass substrate (transparent substrate), or the interface between the silicon layer and the chromium layer (the chromium layer formed between the quartz glass substrate and the silicon layer). Since the light is reflected at different interfaces and again passes through the silicon layer and exits to the light incident side, the reflectance increases, and the reflection noise reduction effect cannot always be obtained sufficiently.

  In addition, since an optical element having a fine concavo-convex structure formed on a quartz glass substrate transmits light while obtaining an antireflection effect, it is possible to obtain a light shielding property in a wavelength region where quartz glass has translucency. Can not.

  The present invention has been made in view of such circumstances, and at least in part, an optical element capable of enhancing a reflection noise reduction effect while obtaining light shielding properties, a method for manufacturing the same, and a Nippon disk using the optical element Another object of the present invention is to provide a confocal optical system and a three-dimensional measuring apparatus using the Nippon disc.

  In order to solve the above problems, an optical element according to a first aspect of the present invention includes a substrate having a first fine concavo-convex structure including a large number of microprojections formed on one surface, and the first fine concavo-convex structure. A metal layer to be covered; and a film having a second fine concavo-convex structure including a large number of fine protrusions formed on the opposite side of the metal layer from the substrate.

  An optical element according to a second aspect of the present invention includes a substrate, a film formed on one surface side of the substrate, the film having a first fine concavo-convex structure including a large number of minute protrusions, A metal layer that covers one fine concavo-convex structure, and a film that is formed on the opposite side of the metal layer from the substrate and that has a second fine concavo-convex structure including a large number of microprojections. Is.

  According to a third aspect of the present invention, there is provided a method of manufacturing an optical element, wherein the one surface of the substrate is dry-etched while depositing a fine mask material on the one surface of the substrate. Forming a first fine concavo-convex structure including a number of microprojections, forming a metal layer so as to cover the first fine concavo-convex structure, and forming a film on the metal layer; Forming a second fine concavo-convex structure including a large number of minute protrusions on the surface of the film by dry etching the surface of the film while depositing a fine mask material on the surface of the film. Is.

  In the method of manufacturing an optical element according to the fourth aspect of the present invention, the surface of the first film is dry-etched while depositing a fine mask material on the surface of the first film formed on one surface side of the substrate. A step of forming a first fine concavo-convex structure including a number of fine protrusions on the surface of the first film, a step of forming a metal layer so as to cover the first fine concavo-convex structure, Forming a second film on the metal layer, and dry-etching the surface of the second film while depositing a fine mask material on the surface of the second film; And forming a second fine concavo-convex structure including a large number of fine protrusions.

  The Nippon disk according to the fifth aspect of the present invention includes a substrate having a first fine concavo-convex structure including a large number of fine protrusions formed on one surface, a metal layer covering the first fine concavo-convex structure, and the metal A film formed on the opposite side of the substrate from the substrate and having a second fine concavo-convex structure including a large number of fine protrusions, and a part of the metal layer and the second fine concavo-convex An opening is formed in a part of the film having a structure.

  A Nippon disk according to a sixth aspect of the present invention is a substrate, a film formed on one surface side of the substrate, the film having a first fine concavo-convex structure including a large number of microprojections, and the first A metal layer that covers one fine concavo-convex structure, and a film that is formed on the opposite side of the metal layer from the substrate and has a second fine concavo-convex structure including a large number of microprojections, An opening is formed in part of the metal layer and part of the film having the second fine concavo-convex structure.

  A confocal optical system according to a seventh aspect of the present invention includes the Nippon disk according to the fifth or sixth aspect as scanning means for scanning a focus position.

  A three-dimensional measuring apparatus according to an eighth aspect of the present invention includes a Nippon disk according to the fifth or sixth aspect, a stage that supports a measurement object, and an objective optical disposed between the Nippon disk and the stage. System.

  According to the present invention, at least in part, an optical element capable of enhancing the reflection noise reduction effect while obtaining a light shielding property, a method for manufacturing the same, a Nippon disk using the optical element, and a computer using the Nippon disk A focal optical system and a three-dimensional measuring apparatus can be provided.

  Hereinafter, an optical element and a manufacturing method thereof according to the present invention, a Nippon disk using the optical element, a confocal optical system using the Nippon disk, and a three-dimensional measuring apparatus will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a schematic plan view showing a Nipkow Disk 10 as an optical element according to the first embodiment of the present invention. The Nippon disc 10 is a shield having a disc-like outline as a whole. The Nippon disc 10 is provided, for example, in a confocal microscope. Although not shown because it is fine, the Nippon Disc 10 has optical openings 14 (see FIG. 2) of the same diameter optically corresponding to pinholes along a plurality of spiral radial trajectories 10a. Many are formed at predetermined intervals. In the example shown in the figure, a case where only four trajectories 10a where the optical apertures 14 are to be formed is shown.

  FIG. 2 is a schematic sectional view schematically showing the Nippon disc 10 shown in FIG. The Nippon disk 10 includes a substrate 11 having a first fine concavo-convex structure MR1 including a large number of minute protrusions CP1 formed on one surface, a metal layer 12 covering the first fine concavo-convex structure MR1, and a substrate of the metal layer 12. 11 is a film 13 formed on the side opposite to 11 and having a second fine concavo-convex structure MR2 including a large number of minute protrusions CP2.

  In the present embodiment, a transparent substrate made of, for example, quartz glass is used as the substrate 11. The substrate 11 is not limited to quartz glass, but it is desirable that the substrate 11 is excellent in transparency with respect to light of the wavelength used by the Nippon disk 10 and has low expansion.

  In FIG. 2, for convenience of drawing, the microprotrusions CP1 and CP2 are described as being regularly distributed. However, in practice, shapes such as heights and intervals may be randomly distributed.

  The material of the metal layer 12 is not particularly limited, but is preferably selected in consideration of adhesion to the substrate 11, light absorption characteristics for light in a relatively long wavelength range, and the like. Considering such points, it is preferable to use chromium or titanium as the material of the metal layer 12.

  As the material of the film 13 in this embodiment, a material having a large absorption coefficient in a wide wavelength range is preferably used. Specifically, a semimetal such as silicon (Si) or various resins can be used. However, it is preferable to use silicon from the viewpoint of easily forming fine irregularities on the surface. When a resin is used as the material of the film 13, for example, a known resin such as vinyl chloride, ABS, or polycarbonate can be appropriately used. In particular, a resin containing an aromatic ring or an unsaturated bond has a large absorption coefficient in the ultraviolet region. Therefore, it is suitable as a material for the film 13. In order to obtain a larger extinction coefficient, the resin may contain a light-absorbing substance such as carbon black, or a substance that absorbs light in the ultraviolet to visible region, such as a commercially available dye or ultraviolet absorber. May be added.

  In the present embodiment, the first minute protrusion CP1 is formed over the entire region of the upper surface of the substrate 11. On the other hand, the metal layer 12 and the film 13 are formed over the entire region other than the optical opening 14, and the optical opening 14 has an opening. The metal layer 12 and the film 13 constitute a light shielding film as a whole.

  In the present embodiment, the optical aperture 14 has a circular shape in plan view, and is disposed, for example, at a position conjugate with an observation point on or inside the object (measurement object) with the objective lens of the confocal microscope interposed therebetween. Is done. The diameter of the optical opening 14 is normally set to the diameter of the air disk, and is about 10 μm in this embodiment. The optical openings 14 as shown in the figure are arranged at equal intervals along the locus 10a shown in FIG.

  The length of the first minute protrusion CP1 is, for example, about 0.3 μm to 5 μm. The thickness of the metal layer 12 is, for example, about 0.03 μm to 0.3 μm. The length of the second minute protrusion CP2 is, for example, about 1 μm to 5 μm. However, it is not limited to these dimensions.

  Next, an example of a manufacturing method of the Nippon disc 10 according to the present embodiment will be described with reference to FIGS. 3 to 5 are schematic cross-sectional views schematically showing each manufacturing process. FIG. 6 is a schematic configuration diagram schematically showing a parallel plate dry etching apparatus 30 used in the process of forming the fine concavo-convex structures MR1 and MR2.

  First, a substrate 11 such as a quartz glass substrate is prepared. Next, the parallel surface dry etching apparatus 30 shown in FIG. 6 is used to dry-etch the one surface of the substrate 11 while depositing the fine mask material SP on the one surface of the substrate 11. A fine concavo-convex structure MR is formed on the surface (FIGS. 3A to 3C). This point will be described below.

  As shown in FIG. 6, the parallel plate dry etching apparatus 30 basically has the same structure as the RIE apparatus, and is applied with an anode electrode 31 connected to the ground and high-frequency power for converting the reaction gas into plasma. A cathode electrode 32 and a vacuum chamber 34 for accommodating these electrodes 31 and 32. The cathode electrode 32 is connected to an AC voltage source 36 that generates a predetermined high-frequency voltage necessary for converting the reaction gas into plasma and forming the fine relief structure MR1.

On the other hand, the vacuum chamber 34 is set to the ground potential similarly to the anode electrode 31. The vacuum chamber 34 can be maintained at an appropriate degree of vacuum by a vacuum pump 38. The reaction gas source 39 is a gas source for supplying a reaction gas to the vacuum chamber 34. By introducing a reaction gas having a necessary flow rate into the vacuum chamber 34, the density of the reaction gas in the vacuum chamber 34 is set to a desired value. Can be set to As the reaction gas supplied from the reaction gas source 39, for example, a mixture of Ar and CF ₄ (carbon tetrafluoride) in an appropriate distribution ratio is used.

  A disc-shaped tray 41 made of alumina, for example, is placed on the cathode electrode 32, and the substrate 11 is placed on the tray 41. The tray 41 functions as a support for the substrate 11 and also functions as a material for a fine mask substance (a fine mask having a low etching rate) SP, as will be described later. The substrate 11 is a simple flat plate before processing. The upper surface of the substrate 11 placed on the tray 41 is etched by the incidence of ions that are converted into plasma and accelerated between the electrodes 31 and 32.

In the case of normal etching, etching is performed uniformly with a predetermined anisotropy in a direction perpendicular to the upper surfaces of both electrodes 31 and 32. However, in this case, since the tray 41 on which the substrate 11 is placed is sputtered and etched by the ions of the reaction gas, fine sputtered particles SP emitted from the tray 41 made of alumina (Al ₂ O ₃ ) are transferred to the substrate. 11 randomly adhere to the surface. However, in the case of a reaction gas composed of Ar and CF ₄ , the sputtering rate of quartz glass (SiO ₂ ) is higher than the sputtering rate of alumina, so that the sputtered particles SP that randomly adhere to the surface of the substrate 11 function as a mask. . As a result, random protrusions CP are formed over the entire surface of the substrate 11 due to the difference in etching rate between the portion where the sputtered particles SP are attached and the portion where the sputtered particles SP are not attached.

  3A to 3C conceptually show the formation of the first fine relief structure MR1 by the apparatus 30 of FIG. FIG. 3A shows an initial stage of forming the first fine uneven structure MR1, FIG. 3B shows an intermediate stage of forming the first fine uneven structure MR1, and FIG. 3C shows the first fine uneven structure MR1. The final stage of formation of uneven structure MR1 is shown.

  In the initial stage shown in FIG. 3A, the surface of the tray 41 is sputtered and etched together with the surface of the substrate 11, so that countless sputtered particles SP that are fine particles of alumina fly from the tray 41 to the substrate 11. , And randomly adhere to the surface of the substrate 11. In the drawing, the sputtered particles SP are distributed at a constant period, but actually, the sputtered particles SP have a random distribution without regularity.

  In the intermediate stage shown in FIG. 3B, since the sputtered particles SP attached to the surface of the substrate 11 function as a mask, anisotropic etching by reactive gas ions GI is performed in a region where the sputtered particles SP are not attached. As it progresses, countless cone-shaped projections CP1 are formed corresponding to the positions of the sputtered particles SP. Although the etching rate is slower than that of the substrate 11, the sputtered particles SP adhering to the surface of the substrate 11 are also etched by the ions GI, so that the tips of the projections CP1 are gradually exposed. However, another sputtered particle SP tends to adhere again to the tip of the protrusion CP1, and as a result, the protrusion CP1 gradually grows as a whole.

  In the final stage shown in FIG. 3C, the protrusion CP1 grows to a size of nanometer order, and the upper layer of the substrate 11 is in a state where the first minute protrusions CP1 are formed densely at random. Thus, the upper layer portion on which the large number of first minute protrusions CP1 are formed constitutes the first minute uneven structure MR1.

  After forming the first fine concavo-convex structure MR1 on one surface of the substrate 11 in this way, the metal layer 12 is formed on the first fine concavo-convex structure MR1 by vapor deposition or the like (FIG. 4A).

  Next, an opening 12a corresponding to the optical opening 14 is formed in the metal layer 12 by photolithography (FIG. 4B).

  Subsequently, a film 13 made of silicon is formed on the metal layer 12 and the first fine concavo-convex structure MR1 by plasma CVD or sputtering, for example, with a thickness of 1 to 10 μm (FIG. 4C).

Thereafter, the top surface of the film 13 is dry-etched while depositing the fine mask material SP on the top surface (surface) of the film 13, thereby forming the second fine relief structure MR2 on the top surface of the film 13 (FIG. 5A). )). Specifically, the same etching as described above may be performed using the parallel plate dry etching apparatus 30 shown in FIG. However, as the reaction gas, for example, a gas composed of Ar, SF ₆ and C ₂ Cl ₄ is used.

  Finally, an opening 13a corresponding to the optical opening 14 is formed in the film 13 by photolithography (FIG. 5B). Thus, the Nippon disc 10 according to the present embodiment is completed.

  Here, a Nippon disc 50 according to a comparative example compared with the Nippon disc 10 according to the present embodiment will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view schematically showing a Nippon disc 50 according to this comparative example, and corresponds to FIG. The difference between the Nippon disk 50 according to this comparative example and the Nippon disk 10 according to this embodiment is that the upper surface of the substrate 11 is not formed on the upper surface of the substrate 11 and the upper surface of the substrate 11 is flat. In connection with this, the metal layer 12 is only formed in a planar shape. The Nippon disc 50 according to this comparative example performs the first fine concavo-convex structure MR1 forming step (steps shown in FIGS. 3A to 3C) among the steps described in the method for manufacturing the Nippon disc 10 described above. It can manufacture by performing the process after Fig.4 (a) without it.

  In the Nippon disk 10 according to the present embodiment and the Nippon disk 50 according to the comparative example, the second fine concavo-convex structure MR2 side (upper side in the figure) is the light incident side. In the following description, the film 13 is described as being made of silicon, but the same applies to the case where the film 13 is a carbon black-containing resin or the like.

  As shown in FIGS. 2 and 7, in any of the Nippon disk 10 according to the present embodiment and the Nippon disk 50 according to the comparative example, the light L1 incident on the optical opening 14 is the film 13 and the metal in the optical opening 14. Since the layer 12 is not formed, the light enters the substrate 11, passes through the substrate 11, and is emitted from the substrate 11.

  Further, in any of the Nippon disks 10 and 50, light in a relatively short wavelength region out of the light L2 incident on the region other than the optical aperture 14 is incident on the incident side due to the antireflection effect by the second fine concavo-convex structure MR2. It is absorbed by the film 13 with almost no return.

  In both of the Nippon discs 10 and 50, the light absorption characteristics of the silicon layer are deteriorated in light having a wavelength longer than about 620 nm in which the transmittance of the silicon layer is increased in the incident light L 2, and a part of the light enters the film 13. It reaches the metal layer 12 without being absorbed. At this time, in the Nippon disk 50 according to the comparative example, since the metal layer 12 is formed in a flat plate shape, the light that has reached the metal layer 12 is reflected at the interface between the film 13 and the metal layer 12, and again passes through the film 13. Since the light passes through and exits to the light incident side, the reflectance increases, and the reflection noise reduction effect cannot always be obtained sufficiently.

  On the other hand, in the Nippon disk 10 according to the present embodiment, the metal layer 12 is formed so as to cover the first fine concavo-convex structure MR1 formed on the surface of the substrate 11, so that the metal layer 12 is reached. The light having a relatively long wavelength is partially reflected by the metal layer 12 and the remaining part enters the metal layer 12 and is absorbed. A part of light reflected by the metal layer 12 without entering the metal layer 12 is incident again on the metal layer on the adjacent minute protrusion CP1, and these operations are repeated, so that light having a relatively long wavelength is emitted. It is absorbed by the metal layer 12. For this reason, in the optical element 10 according to the present embodiment, the light having a relatively long wavelength out of the incident light L2 is hardly reflected and returned to the incident side. Therefore, according to the present embodiment, it is possible to enhance the reflection noise reduction effect while obtaining a light shielding property in a region other than the optical aperture 14.

  As described above, in the Nippon disk 10 according to the present embodiment, the metal layer 12 formed so as to cover the first fine concavo-convex structure MR1 formed on the surface of the substrate 11 efficiently absorbs long-wavelength light. Since it functions as a fine light trap, low reflection can be realized even for long-wavelength light transmitted through the film 13.

  As a sample of an example of the present invention, a sample corresponding to the Nippon disc 10 according to the present embodiment was actually manufactured by the manufacturing method described above. However, in the sample of this example, the optical opening 14 was not formed without performing the photolithography etching process of FIG. 4B and the photolithography etching process of FIG. Further, a sample corresponding to the Nippon disc 50 according to the comparative example was actually produced by the manufacturing method described above. Also in the sample of this comparative example, the optical aperture 14 was not formed.

Their actual manufacturing conditions were as follows. First, the manufacturing conditions and the like of the sample of this example will be described. In the case of the sample of this example, a quartz glass substrate having a square shape with a side of 3 inches and a thickness of 2.5 mm was used as the substrate 11. Then, a first fine concavo-convex structure MR1 was formed on one surface of the quartz glass substrate using a parallel plate dry etching apparatus 30 shown in FIG. At this time, the tray 41 is made of alumina, CF ₄ gas from the reaction gas source 39 is introduced into the vacuum chamber 34 at a flow rate of 10 sccm, and Ar gas is introduced into the vacuum chamber 34 at a flow rate of 10 sccm. A high frequency RF power density of 0.1 w / cm ² was applied to 32 and the dry etching described above was performed. The etching time was 20 minutes. According to the electron micrograph, the length of the first minute protrusion CP1 of the first fine concavo-convex structure MR1 formed thereby was approximately 1 μm. A Cr film having a thickness of 0.2 μm was formed as the metal layer 12 on the first fine relief structure MR1 by vapor deposition. Further, a silicon film having a thickness of 2.5 μm was formed as the film 13 by RF sputtering. Thereafter, a second fine concavo-convex structure MR2 was formed on the surface of the silicon film (film 13) using a parallel plate dry etching apparatus 30 shown in FIG. At this time, the tray 41 is made of alumina, and C ₂ Cl ₄ gas is introduced into the vacuum chamber 34 from the reaction gas source 39 at a flow rate of 20 sccm, O ₂ gas at a flow rate of 10 sccm, and SF ₆ gas at a flow rate of 10 sccm. The pressure in the chamber 34 was 6 Pa, a high frequency RF power density of 0.07 w / cm ² was applied to the cathode electrode 32, and the dry etching described above was performed. The etching time was 30 minutes. According to the electron micrograph, the length of the second minute protrusion CP2 of the second fine concavo-convex structure MR2 formed thereby was approximately 2 μm. Thereby, the sample of the present Example was completed.

  The manufacturing conditions of the sample of the comparative example were the same as those of the sample of the example except that the first fine concavo-convex structure MR1 was not formed.

  The reflection spectrum was measured for the sample of this example and the sample of the comparative example prepared in this way. The measurement results are shown in FIG.

  As can be seen from FIG. 8, the reflectance of the sample of the comparative example is large in the wavelength region of about 680 μm or more, whereas the sample of the example is almost 0% in the wavelength region of about 680 μm or more. Therefore, low reflection is realized even for long wavelength light.

  [Second Embodiment]

  FIG. 9 is a schematic sectional view showing a Nippon disc 60 according to the second embodiment of the present invention, and corresponds to FIG. 9, elements that are the same as or correspond to elements in FIG. 2 are given the same reference numerals, and redundant descriptions thereof are omitted.

  The difference between the Nippon disk 60 according to the present embodiment and the Nippon disk 10 according to the first embodiment is that the first fine concavo-convex structure MR1 is not formed on the surface of the substrate 11 and the surface of the substrate 11 is flat. The first fine concavo-convex structure MR1 is formed on the surface of the film 62 such as a silicon film formed on the substrate 11, and the film 62 is the same as the metal layer 12 and the film 13. In addition, the optical opening 14 has only an opening.

  Here, an example of a manufacturing method of the Nippon disc 60 according to the present embodiment will be described with reference to FIGS. 10 to 12 are schematic cross-sectional views schematically showing each manufacturing process.

  First, a substrate 11 such as a quartz glass substrate is prepared, and a film 62 made of silicon is formed on the substrate 11 by plasma CVD or sputtering, for example, with a thickness of 1 to 10 μm (FIG. 10A).

Next, the first fine concavo-convex structure MR1 is formed on the upper surface of the film 62 by dry-etching the upper surface of the film 62 while depositing the fine mask material SP on the upper surface (front surface) of the film 62 (FIG. 10 ( b)). Specifically, the same etching as described above may be performed using the parallel plate dry etching apparatus 30 shown in FIG. However, as the reaction gas, for example, a gas composed of Ar, SF ₆ and C ₂ Cl ₄ is used.

  Next, a metal layer 12 is formed on the first fine concavo-convex structure MR1 by vapor deposition or the like (FIG. 11A).

  Next, an opening 12a corresponding to the optical opening 14 is formed in the metal layer 12 by photolithography (FIG. 11B).

  Subsequently, a film 13 made of silicon is formed on the metal layer 12 and the first fine concavo-convex structure MR1 by plasma CVD or sputtering, for example, with a thickness of 1 to 10 μm (FIG. 11C).

Thereafter, the top surface of the film 13 is dry-etched while depositing the fine mask material SP on the top surface (surface) of the film 13, thereby forming the second fine relief structure MR2 on the top surface of the film 13 (FIG. 12A). )). Specifically, the same etching as described above may be performed using the parallel plate dry etching apparatus 30 shown in FIG. However, as the reaction gas, for example, a gas composed of Ar, SF ₆ and C ₂ Cl ₄ is used.

  Finally, openings 13a and 62a corresponding to the optical openings 14 are formed in the films 13 and 62, respectively, by photolithography (FIG. 12B). Thus, the Nippon disc 60 according to the present embodiment is completed.

  The same advantage as the Nippon disk 10 according to the first embodiment can be obtained by the Nippon disk 60 according to the present embodiment.

  [Third Embodiment]

  FIG. 13 is a schematic configuration diagram showing a three-dimensional measuring apparatus 200 according to the third embodiment of the present invention. In this three-dimensional measuring apparatus, the Nippon disk 10 or 60 according to the first or second embodiment is mounted.

  The three-dimensional measuring apparatus 200 includes an epi-illumination light source 250 for illuminating the measurement target MO mounted on the stage ST, and condenses the illumination light from the epi-illumination light source 250 on the measurement target MO. An epi-focal confocal optical system 260 for extracting reflected light from the MO, an imaging device 270 that captures the reflected light extracted by the epi-focal confocal optical system 260, and a camera for observing an entity image of the measurement target MO An observation optical system 280 and a laser AF system 290 for adjusting the focus during camera observation are provided.

  The epi-illumination light source 250 incorporates a mercury lamp as a light source, and guides the illumination light from the lamp device 255 to the polarization beam splitter 252 through the fiber 251. A polarizing plate 254 that aligns the polarization direction of the illumination light in a specific direction is disposed between the fiber 251 and the polarization beam splitter 252.

  The epi-illumination confocal optical system 260 includes first and second objective lenses 261 and 262 that are both-side telecentric objective optical systems, and a Nippon disk 10 (60) that rotates at a constant speed. The first objective lens 261 is disposed on the measurement object MO side, and can be displaced to an appropriate position in the optical axis OA direction by the focus shifting mechanism 264. The second objective lens 262 collects the image light collimated by the first objective lens 261 on the light shielding layer of the Nippon disk 10 (60) at an appropriate magnification. The Nippon disc 10 (60) is the one described in the first embodiment and the second embodiment, and functions as scanning means in the incident-light confocal optical system 260.

  The Nippon disk 10 (60) is arranged perpendicular to the optical axis OA so that the normal direction of the disk and the optical axis OA are in the same direction, and is driven by the driving device 265 to be a rotation axis RA parallel to the optical axis OA. It rotates at a constant speed around. At this time, the pinhole 10b (corresponding to the optical opening 14 in FIG. 2) formed in the Nippon disk 10 (60) and the measurement object MO are arranged at conjugate positions. Therefore, a large number of focused spots scan and move along the XY cross section of the measurement object MO, and reflected light from the focused spots passes through the pinhole 10b and is guided to the imaging device 270 side. Thereby, an XY cross-sectional image of the measurement object MO can be obtained.

  The imaging device 270 includes, for example, a projection system 271 for projecting an image of the pinhole 10b formed on the Nippon disk 10 (60) at an equal magnification, a half mirror 272 arranged at the rear stage of the projection system 271, and a half mirror. 272 includes a high-sensitivity camera 273 disposed on an optical path that goes straight through 272 and a low-sensitivity camera 274 disposed on an optical path bent by the half mirror 272. Among these, the projection system 271 is a double-sided telecentric system composed of a pair of lenses 271a and 271b, and a polarizing plate 276 that extracts polarized light in a specific direction from the observation light is disposed between the lenses 271a and 271b. The high-sensitivity camera 273 is for observing a scanning image of the measurement target MO with the Nippon disc 10 (60) or the like with high sensitivity, and the low-sensitivity camera 274 is a measurement target with the Nippon disc 10 (60) or the like. This is for observing the scanning image of the MO at a low speed.

  The observation optical system 280 includes an advancing / retracting mirror 281 that can be moved back and forth on the optical axis OA of the epi-focal confocal optical system 260, an optical path bending mirror 282 that is fixedly disposed, and a zoom optical system 283 for zooming. A bright field camera 284 for bright field observation, a coaxial illumination device 285 for bright field observation, and a beam splitter 286 for guiding bright field illumination light onto the observation optical path. When the forward / backward mirror 281 is arranged on the optical axis OA, the zoom optical system 283 can be adjusted while observing with the bright field camera 284, and the real image of the measurement object MO can be scaled.

  The laser AF system 290 includes a half mirror 291, a relay system 292, a splitter mirror 293, a pair of lenses 294 and 295, and a pair of sensors 296 and 297. By monitoring the outputs of the pair of sensors 296, 297, the in-focus state with respect to the measurement object MO can be detected, and the in-focus state is maintained by appropriately moving the first objective lens 261 by the defocusing mechanism 264. Can do.

  The operation of the apparatus shown in FIG. 13 will be described. Light emitted from the epi-illumination light source 250 is reflected by the polarization beam splitter 252 and applied to the Nippon disk 10 (60). This light passes through the pinhole 10b (corresponding to the optical aperture 14 shown in FIG. 2) of the Nippon disk 10 (60), and is condensed on the measurement object MO by the objective lenses 261 and 262. The reflected light from the measurement object MO passes through the pinhole 10b of the Nippon disk 10 (60) via the objective lenses 261 and 262 again. Here, the pinhole 10b through which the reflected light passes is the same as the original pinhole 10b through which the illumination light condensed on the measurement object MO has passed. In this way, the light that has passed through the pinhole 10 b of the Nippon disk 10 (60) passes through the polarization beam splitter 252 and forms an image on the imaging surfaces of the cameras 273 and 274 via the projection system 271.

  At this time, since the Nippon disk 10 (60) is rotationally driven by the driving device 265, the spot-like illumination light guided to the measurement target MO is scanned in the XY plane on the measurement target MO. The cameras 273 and 274 can obtain an image of the entire measurement target MO within the above-described scanning range by loading. In detecting such an image, if the first objective lens 262 is displaced by the defocusing mechanism 264, sectioning of the measurement object MO is possible, and if the image thus obtained is analyzed, the measurement object MO is analyzed. The three-dimensional characteristic distribution and shape can be determined.

  In the above three-dimensional measuring apparatus 200, since the Nippon disk 10 (60) with little reflected light is used, it is difficult for noise to be placed on the observation light detected by the high-sensitivity camera 273 or the like. Therefore, a tomographic image or the like can be measured with high accuracy for the measurement object MO. Furthermore, since the in-focus position gradually changes up and down by gradually moving the first objective lens 261 by the focus shift mechanism 264, a three-dimensional image in which the position in the depth direction for extracting the tomographic image is changed can be simplified. In addition, it can be obtained with high accuracy.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

  For example, the optical element according to the present invention is not limited to a Nippon disk, but can be applied to various masks having a predetermined pattern of light shielding layer or light shielding layer on a transparent substrate, a diaphragm, and the like. When the optical element according to the present invention is used as a light absorbing member that absorbs unnecessary light or the like, it is not necessary to form the optical opening 14, and the substrate 11 does not necessarily have to be transparent.

1 is a schematic plan view showing a Nippon disc according to a first embodiment of the present invention. It is a schematic sectional drawing which shows typically the Nippon disc shown in FIG. It is process drawing which shows the manufacturing method of the Nippon disc shown in FIG. FIG. 4 is a process diagram illustrating a process subsequent to FIG. 3. It is process drawing which shows the process following FIG. It is a schematic block diagram which shows typically the parallel plate dry etching apparatus used with the manufacturing method of the Nippon disk shown in FIG. It is a schematic sectional drawing which shows typically the Nippon disc by a comparative example. It is a figure which shows the reflection spectrum of the sample of the Example of this invention, and the sample by a comparative example. It is a schematic sectional drawing which shows the Nippon disk by the 2nd Embodiment of this invention. It is process drawing which shows the manufacturing method of the Nippon disc shown in FIG. It is process drawing which shows the process following FIG. FIG. 12 is a process diagram illustrating a process continued from FIG. 11. It is a schematic block diagram which shows the three-dimensional measuring apparatus by the 3rd Embodiment of this invention.

Explanation of symbols

10,60 Nippon disc (optical element)
DESCRIPTION OF SYMBOLS 11 Board | substrate 12 Metal layer 13 Film | membrane CP1, CP2 Microprotrusion MR1 1st fine uneven structure MR2 2nd fine uneven structure

Claims (12)

A substrate having a first fine relief structure including a plurality of randomly distributed microprojections formed on one surface;
A metal layer covering the first fine relief structure;
A film having a second fine concavo-convex structure including a large number of randomly distributed microprojections formed on the opposite side of the metal layer from the substrate;
An optical aperture through which incident light passes;
An optical element comprising:
The substrate is a transparent substrate at the wavelength used;
The incident light passes through the substrate after passing through the optical opening and is emitted to the outside of the optical element.
An optical element. A substrate,
A film formed on one surface side of the substrate, the film having a first fine concavo-convex structure including a large number of randomly distributed microprojections;
A metal layer covering the first fine relief structure;
A film formed on the opposite side of the metal layer from the substrate and having a second fine concavo-convex structure including a large number of randomly distributed microprojections;
An optical aperture through which incident light passes;
An optical element comprising:
The substrate is a transparent substrate at the wavelength used;
The incident light passes through the substrate after passing through the optical opening and is emitted to the outside of the optical element.
An optical element.   The distribution pattern of the large number of microprotrusions of the first fine concavo-convex structure and the distribution pattern of the large number of microprotrusions of the second fine concavo-convex structure are independent of each other. 2. The optical element according to 2. It said second film having a fine relief structure, an optical element according to any one of claims 1 to 3, characterized in that it consists of silicon or resin. The optical element according to any one of claims 1 to 4, characterized in that said substrate is made of quartz glass. The optical element according to any one of claims 1 to 5 wherein the metal layer is characterized by comprising a chromium or titanium. Some of the film having a part and the second of the fine unevenness of the metal layer, in any one of claims 1 to 6, characterized in that openings corresponding to the optical apertures are formed The optical element described. A substrate having a first fine relief structure including a plurality of randomly distributed microprojections formed on one surface;
A metal layer covering the first fine relief structure;
A film formed on the opposite side of the metal layer from the substrate and having a second fine concavo-convex structure including a large number of randomly distributed microprojections;
With
A Nippon disk, wherein an opening is formed in a part of the metal layer and a part of the film having the second fine concavo-convex structure. A substrate,
A film formed on one surface side of the substrate, the film having a first fine concavo-convex structure including a large number of randomly distributed microprojections;
A metal layer covering the first fine relief structure;
A film formed on the opposite side of the metal layer from the substrate and having a second fine concavo-convex structure including a large number of randomly distributed microprojections;
With
A Nippon disk, wherein an opening is formed in a part of the metal layer and a part of the film having the second fine concavo-convex structure. Wherein the first of said plurality of said plurality of microprojections of the distribution pattern of the distribution pattern and the second of the fine unevenness of the microprojections of the fine unevenness, claim 8 or characterized by being independent independently of one another 9. The Nippon disc according to 9 . The Nipkow disk according to any one of claims 8 to 10, a confocal optical system characterized by comprising a scanning means for scanning the focus position. The Nippon disc according to any one of claims 8 to 10 ,
A stage that supports the measurement object;
An objective optical system disposed between the Nippon disc and the stage;
A three-dimensional measuring apparatus comprising:

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