JP4260645B2 - Manufacturing method of near-field optical head - Google Patents

Description

  The present invention relates to a method for manufacturing a near-field optical head.

  Information recording / reproducing apparatuses using light have evolved toward a larger capacity and a smaller size, and accordingly, a higher recording capacity is required. As a countermeasure, for example, a device using a blue-violet semiconductor laser has been developed. However, these techniques can only improve the current recording density by several times due to the problem of the diffraction limit of light. On the other hand, an information recording / reproducing method using near-field light is expected as a technique for handling optical information in a minute region exceeding the diffraction limit of light.

  This technique uses near-field light generated in the vicinity of an optical minute aperture or minute projection having a size equal to or smaller than the wavelength of light, which is a near-field light generating element formed in a near-field light head. As a method for reproducing optical information, the recording medium surface is irradiated with near-field light generated from a microscopic aperture or a microprotrusion, and the recording medium surface on which the optical constants such as microscopic unevenness and refractive index on which information is recorded is changed. A method (illumination mode) in which scattered light converted by the above interaction is detected by a separately provided light receiving element is possible. Also, near-field light localized on the recording medium can be used. As a method of reproducing optical information, a method of converting near-field light localized on a minute mark on a recording medium into scattered light by interacting with a minute aperture or minute protrusion by irradiating the surface of the recording medium with light ( (Collection mode) is possible. This makes it possible to handle optical information in a region that is less than or equal to the wavelength of light, which is a limit in conventional optical systems. Optical information is recorded by irradiating the surface of the recording medium with near-field light generated from a minute aperture, changing the shape of a minute area on the medium (heat mode recording), or refraction or transmission of the minute area. This is done by changing the rate (photon mode recording). By using these near-field optical heads having optical apertures and projections exceeding the diffraction limit of light, a higher density than that of a conventional information recording / reproducing apparatus is achieved.

  In general, the configuration of a recording / reproducing apparatus using near-field light is almost the same as that of a magnetic disk device, except that a near-field light head is used instead of a magnetic head. A near-field optical head with optical micro-apertures and micro-protrusions attached to the tip of the suspension arm is levitated to a certain height using the flying head technology using air bearings, and an arbitrary data mark on the disk is accessed. To do. In order to make the near-field optical head follow the disk that rotates at high speed, it has a flexure function that stabilizes the posture in response to the waviness of the disk (see, for example, Patent Document 1).

  In such a near-field optical head, an optical fiber or an optical waveguide is connected to the side of the head, and the propagation direction is opened by reflecting the light from the optical fiber or optical waveguide propagating in the horizontal direction to the media surface. A method has been devised in which a minute beam spot is incident on an optical minute aperture using a light reflecting surface directed in the direction. (Refer to Patent Document 2.) This makes it possible to reduce the size and thickness of a recording / reproducing apparatus using near-field light.

  A conventional manufacturing method of such a near-field optical head is shown in FIG. First, as shown in FIG. 6A, a glass substrate 1001 is prepared. Next, as shown in FIG. 6B, a lens 1002 is formed on the upper surface of the glass substrate 1001. When the lens 1002 is a diffractive Fresnel lens or a Fresnel zone plate, it can be formed by a combination of photolithography and dry etching. Next, as shown in FIG. 6C, a protrusion 1003 and an ABS (air bearing surface) 1004 are formed on the lower surface of the glass substrate 1001. For the formation of the protrusion 1003 and the ABS 1004, a combination of photolithography and wet etching capable of isotropic etching is used. Next, as illustrated in FIG. 6D, a light shielding film 1005 is formed on the protrusion 1003, and an optical minute opening 1006 is formed at the apex of the light shielding film 1005. For the formation of the optical minute opening 1006, a method is used in which a part of the light shielding film 1005 is removed by irradiation with a focused ion beam (FIB) so that the apex of the protrusion 1003 is minutely exposed. Alternatively, a method may be used in which the light shielding film 1005 is plastically deformed by pressing a hard flat plate against the light shielding film 1005 on the top of the protrusion 1003 so that the top of the protrusion 1003 is exposed minutely. Next, as shown in FIG. 6E, a silicon substrate 1007 is prepared. Next, as shown in FIG. 6F, a light reflecting surface 1008 and a V groove 1009 are formed by a combination of photolithography and crystal anisotropic etching. Next, as shown in FIG. 6G, a metal film 1010 is formed on the light reflecting surface 1008. Finally, as shown in FIG. 6H, the optical fiber 1011 is bonded along the V-groove 1009, and then the processed glass substrate 1001 and the silicon substrate 1007 are bonded together to complete the near-field optical head.

Moreover, a lens can be abolished by making a light reflection surface into a curved surface. (See Patent Document 2.) First, a silicon substrate is crystal-anisotropically etched to form an inverted pyramid-shaped depression composed of four oblique planes. By laminating a material to be an optical waveguide sufficiently thick on a silicon substrate including four oblique planes, four curved surfaces are formed on the surface of the optical waveguide laminated on the four oblique planes. Further, processing is performed by photolithography so as to leave at least one of the curved surfaces. A metal film is formed on the remaining curved surface to form a light reflecting surface. The light passing through the optical waveguide strikes this light reflecting surface and is guided while being condensed to an optical minute aperture provided below the silicon substrate.
Japanese Patent Application Laid-Open No. 2001-34981 (page 4, FIG. 1) International Patent Publication No. 00/28536 pamphlet (pages 41 to 46, FIGS. 5 and 6)

  However, it can be said that the structure of the near-field optical head according to the conventional method considers mass productivity because it can be manufactured by applying the semiconductor manufacturing process. However, the number of steps is large, and the shape of each element, especially the light reflecting surface, is controlled. Therefore, it is not always an excellent method for mass-producing near-field optical heads with sufficient performance.

  Further, since the degree of freedom of the shape obtained by the conventional method is low, it is difficult to improve the performance of the near-field optical head.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a near-field optical head that can obtain a degree of freedom in shape and is superior in mass productivity and low cost.

  In order to solve the above problems, a method of manufacturing a near-field optical head of the present invention includes a substrate, a near-field light generating element including a cone or a frustum formed on the lower surface of the substrate, and a near-field light generating element. As a manufacturing method for manufacturing a near-field optical head having an air bearing surface that is substantially coplanar, it is formed by a rough shape forming process in which a rough shape of the near field optical head is formed by mold transfer processing, and a rough shape forming process. A polishing process for polishing the top surface of the rough shape of the pyramid or frustum and the rough shape of the air bearing surface, and a shaping process for etching the rough shape of the pyramid or frustum and the air bearing surface And forming a near-field light generating element and an air bearing.

The polishing step may be performed by simultaneously polishing the approximate top surface of the cone or frustum and the approximate top surface of the air bearing surface. This enables an air bearing surface that is substantially flush with the near-field light generating element.
When the near-field optical head has an optical component, the optical component may be simultaneously formed on the upper surface of the substrate by a rough shape forming process.

Then, after the rough shape forming step, a protective film forming step of forming a protective film for maintaining the shape of the optical component on the upper surface of the substrate may be included.
In the near-field optical head manufacturing method of the present invention, a resist pattern having the shape of an optical component is formed on the substrate, and the substrate is etched while etching the resist pattern, whereby the shape of the optical component is transferred to the upper surface of the substrate. Including the step of: This resist pattern may be formed using a gray scale mask or may be formed using an electron beam exposure apparatus.

  Further, in the method of manufacturing the near-field optical head of the present invention, the substrate is divided into an upper substrate on which optical components are formed, a near-field light generating element, and a lower substrate on which an air bearing surface is formed. A step of forming the air bearing surface on the lower substrate, forming the optical component on the upper substrate, and bonding the upper substrate and the lower substrate may be included.

  According to the present invention, most structures of the near-field optical head can be formed by mold transfer processing. Further, the near-field light generating element and the air bearing surface can be formed on substantially the same plane by polishing. Further, the cone or frustum included in the near-field light generating element can be formed by etching. Accordingly, the near-field optical head can be mass-produced at low cost while maintaining the conventional performance.

  Further, according to the present invention, since the projection having the light reflecting surface can be formed by mold transfer processing, a near-field optical head with uniform performance can be mass-produced by using a mold having a good shape accuracy. Can do.

  Further, according to the present invention, since the lens can be formed by mold transfer processing, a high performance near-field optical head can be easily manufactured.

  Further, according to the present invention, the shape of the die, the shape of the frustum, the shape of the projection having the light reflecting surface, and the shape of the lens can be freely formed by forming the shape of the mold freely. Thereby, a high performance near-field optical head can be easily manufactured.

  Further, according to the present invention, since a relatively inexpensive material such as an optical glass for a molded lens can be used as the material, a near-field optical head can be produced at a low cost.

  In addition, according to the present invention, almost all structures of the near-field optical head can be formed by a small number of photolithography processes and etching processes, so that the near-field light having the same performance can be maintained while maintaining the conventional performance. The head can be mass-produced at a low cost.

  Further, according to the present invention, the shape of a cone or a frustum, the shape of a projection having a light reflecting surface, and the shape of a lens can be freely formed by using a gray mask technology or an EB drawing technology. Thereby, a high performance near-field optical head can be easily manufactured.

  Further, according to the present invention, a material that is relatively difficult to process, such as quartz glass, can be used.

  In addition, according to the present invention, since a plurality of near-field optical heads can be formed at the same time, it can be mass-produced at a lower cost.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a trihedral view showing the configuration of a near-field optical head according to Embodiment 1 of the present invention.

  The optically transparent substrate 101 has a protrusion 103 on its lower surface. The protrusion 103 is covered with a light shielding film 104, and an optical minute opening 102 is formed at the tip of the protrusion 103. Further, an ABS (air bearing surface) 105 is formed on the lower surface of the substrate 101, and the ABS 105 constitutes substantially the same plane as the optical minute aperture 102. On the upper surface of the substrate 101, a concave mirror 106 having a substantially quadrispherical shape is formed. However, the mirror surface 107 of the concave mirror 106 has an aspherical shape, and the other surface includes a flat surface 108 that is substantially perpendicular to the substrate 101 and a surface that contacts the substrate 101. A reflective film may be formed on the mirror surface 107. A V-shaped groove 109 is further formed on the upper surface of the substrate 101. An optical fiber 110 is fixed in the V-shaped groove 109, and the optical fiber 110 and the substrate 101 are arranged in parallel. The light emitted from the end face of the optical fiber 110 fixed to the V groove 109 enters the mirror surface 107 through the flat surface 108. The light incident on the mirror surface 107 changes its direction toward the inside of the substrate 101 while being condensed, and is guided to the optical minute opening 102 through the protrusion 103.

  FIG. 2 is a cross-sectional view showing a method of manufacturing a near-field optical head according to Embodiment 1 of the present invention.

  First, as shown in FIG. 2A, a substrate 101 having a concave mirror 106, a V-shaped groove 109, a frustum 201 as a prototype of the projection 103, a convex portion 202 as a prototype of the ABS 105, and the like is used with a predetermined mold. It is formed by mold transfer processing (for example, press processing). As the material of the substrate 101, optical glass for mold lenses can be used. Thereafter, the lower surface of the substrate 101 formed by mold transfer processing is polished so that the top surfaces of the frustum 201 and the convex portion 202 are substantially flush with each other. Chemical mechanical polishing (CMP) may be used for polishing the lower surface of the substrate 101.

  Next, as shown in FIG. 2B, a protective film 203 is formed on the upper surface of the substrate 101 so as to cover the concave mirror 106 and the V groove 109. Thereafter, the substrate 101 is etched. For the etching, an etchant that causes isotropic etching is used. For example, hydrofluoric acid aqueous solution is mentioned. The frustum 201 and the projection 202 formed on the lower surface of the substrate 101 are isotropically etched, and the frustum 201 is sharpened. The frustum 201 is sufficiently etched to become the protrusion 103, and at the same time, the convex portion 202 becomes the ABS 105. The apex of the protrusion 103 is substantially flush with the ABS 105. Since the protective film 203 is not affected by the etchant, the concave mirror 106 and the V groove 109 are protected by the protective film 203 and are not affected by the etchant.

  Next, as shown in FIG. 2C, the protective film 203 is removed, and a light shielding film 104 is formed on the protrusion 103. A metal film such as Al or Au can be used for the light shielding film 104. A film can be formed by a technique such as sputtering, vacuum deposition, or ion plating, and the light shielding film 104 can be formed using a photolithography technique. it can. The thickness of the light shielding film 104 is about several nm to several hundred nm. Thereafter, an optical minute opening 102 is formed. For the formation of the optical minute aperture 102, it is preferable to use a method in which a part of the light shielding film 104 is removed by irradiation with a focused ion beam (FIB) so that the apex of the protrusion 103 is minutely exposed. Alternatively, a method may be used in which the light shielding film 104 is plastically deformed by pressing a hard flat plate against the light shielding film 104 on the top of the protrusion 103 to expose the top of the protrusion 103 minutely.

  Next, as shown in FIG. 2D, the optical fiber 110 is fixed on the V-shaped groove 109 to complete the process.

  In this embodiment, most structures can be formed by mold transfer processing, and the protrusion 103 can be formed by etching, so that mass production can be performed at low cost while maintaining the conventional performance. Can do.

  Further, in this near-field optical head, it is necessary to guide the light emitted from the optical fiber 110 to the optical micro-aperture 102 with high accuracy. By using a mold with high shape accuracy, the near-field optical head with stable shape accuracy is used. Can be mass-produced.

  In addition, since the shape of the mold used in the mold transfer process can be freely formed, the shape of the frustum 201, the shape of the protrusion 103, and the curved surface shape of the concave mirror 106 can be freely formed. Thereby, the protrusion 103 and the concave mirror 106 having excellent light collecting performance can be obtained.

  In addition, since polishing is performed so that the top surfaces of the frustum 201 and the convex portion 202 are substantially in the same plane, the optical minute aperture 102 and the ABS 105 located at the tip of the protrusion 103 may exist on substantially the same plane. it can.

  Further, since a relatively inexpensive material such as a molded lens optical glass can be used as the material of the near-field optical head, it can be produced at low cost.

In the embodiment described above, there is one near-field optical head to be processed, but a plurality of near-field optical heads can be formed simultaneously. For example, it is conceivable that a plurality of substrates 101 connected to each other are subjected to mold transfer processing, the projections 103 are formed by etching, the light-shielding film 104 and the optical minute openings 102 are formed, and then the substrates 101 are separated by dicing. . This method enables mass production at a lower cost.
(Embodiment 2)
FIG. 3 is a cross-sectional view showing a method for manufacturing a near-field optical head according to Embodiment 2 of the present invention.

  The near-field optical head manufactured here has substantially the same structure as the near-field optical head shown in the first embodiment.

  First, as shown in FIG. 3A, a resist 302 is applied to the upper surface of the substrate 301. For the substrate, an optically transparent material such as quartz glass is used. The resist is preferably applied by spin coating or spray coating.

  Next, as shown in FIG. 3B, the resist 302 is irradiated with light and developed. In general photolithography, a pattern is transferred to a resist using a black-and-white binary photomask. Here, a grayscale photomask is used. Therefore, the side surface of the resist 302 to which the pattern is transferred can include a slope or a curved surface. The same can be done by using an electron beam resist and an electron beam drawing apparatus instead of the gray mask. The electron beam drawing apparatus draws a pattern on the electron beam resist by scanning the electron beam spot. Here, the intensity of the electron beam spot may be changed stepwise during the scanning. By these techniques, the resist 302 is formed in a shape corresponding to an optical component such as the concave mirror 108 and the V groove 109 having a curved surface and a slope.

Next, as shown in FIG. 3C, the upper surface of the substrate 301 is etched. By this etching, the shape of the resist 302 is transferred, and the concave mirror 10 8 and the V groove 109 are formed on the upper surface of the substrate 301. For the etching, reactive ion etching (RIE) is preferably used. What is important here is the ratio (selection ratio) between the etching rate of the substrate 301 and the resist 302. If the selection ratio is 1: 1, the substrate 301 and the resist 302 are etched by the same amount, and when the resist 302 is completely etched and disappears, the shape almost the same as the three-dimensional shape of the resist 302 is formed on the substrate. An upper surface of 301 is formed by etching. If the etching rate of the resist 302 is larger than the etching rate of the substrate 301, the substrate 301 is etched less than the resist 302. Therefore, when the resist 302 is completely etched and disappears, the three-dimensional shape of the resist 302 is changed in the vertical direction. The shape compressed into
That is, a shape with a reduced aspect ratio is formed on the upper surface of the substrate 301 by etching. Similarly, if the etching rate of the resist 302 is lower than the etching rate of the substrate 301, the substrate 301 is etched more than the resist 302. Therefore, when the resist 302 is completely etched and disappears, the three-dimensional shape of the resist 302 is obtained. A shape obtained by stretching vertically in the vertical direction, that is, a shape having a large aspect ratio is formed on the upper surface of the substrate 301 by etching. Further, the selection ratio can be controlled by selecting an etching gas. For example, when quartz glass is used for the substrate 301, the selection ratio can be approximately 1: 1 by mixing CHF ₃ gas and Ar gas.

  Next, as shown in FIG. 3D, the lower surface of the substrate 301 is etched to form the protrusion 103 and the ABS 105. The protrusion 103 and the ABS 105 are formed at predetermined positions by being aligned with the shape of the upper surface of the substrate 301. A double-sided alignment exposure apparatus may be used for this alignment. In this etching, the resist may be patterned and etched using a general photolithography technique, or a technique using a gray mask or an EB drawing apparatus shown in FIGS. 3A to 3C may be used. good. When quartz glass is used for the substrate 301, hydrofluoric acid is preferably used for the former etching.

  Next, as shown in FIG. 3E, a light shielding film 104 is formed on the protrusion 103 and an optical minute opening 102 is formed by a method similar to that of the first embodiment. Thereafter, the optical fiber 110 is fixed on the V groove 109 to complete the process.

  In this embodiment mode, most structures can be formed by a small number of photolithography steps and etching steps, so that mass production can be performed at low cost while maintaining the conventional performance.

  In addition, in the near-field optical head, it is necessary to accurately guide the light emitted from the optical fiber 110 to the optical micro-aperture 102. By using the double-sided alignment exposure apparatus, mass production of a near-field optical head with stable accuracy is possible. can do.

Further, by using the gray mask techniques and EB lithography technology, the shape of the projections 103, and the curved shape of the concave mirror 108 can be freely formed. Thus, excellent projection 103 of the condensing performance can be obtained concave mirror 108.

  Further, a material such as quartz glass which is difficult to process by the method described in Embodiment Mode 1 can be used.

In the embodiment described above, since photolithography is used for most processes, it is easy to form a plurality of near-field optical heads simultaneously. For example, it is conceivable that a plurality of substrates 301 connected to each other is formed on one substrate, and then the substrates 301 are separated by dicing. This method enables mass production at a lower cost.
(Embodiment 3)
FIG. 4 is a sectional view showing a method for manufacturing a near-field optical head according to Embodiment 3 of the present invention.

  The near-field optical head manufactured here is almost the same as the near-field optical head according to the first embodiment. This embodiment is substantially the same as the manufacturing method shown in Embodiments 1 and 2, except that the substrates are divided into upper and lower parts and then formed, and then combined.

  First, as shown in FIG. 4A, an optically transparent lower substrate 401 is prepared.

  Next, as shown in FIG. 4B, the lower surface of the lower substrate 401 is etched by the same method as in the first embodiment to form the protrusion 103 and the ABS 105.

  Next, as shown in FIG. 4C, a light shielding film 104 is formed on the protrusion 103 and an optical minute opening 102 is formed by the same method as in the second embodiment.

  Next, as shown in FIG. 4D, an optically transparent upper substrate 402 is prepared, and a resist 302 is applied to the upper surface of the upper substrate 402 by the same method as in the second embodiment.

  Next, as shown in FIG. 4E, the resist 302 is irradiated with light and developed in the same manner as in the second embodiment.

Next, as shown in FIG. 4F, the upper surface of the upper substrate 402 is etched by the same method as in the second embodiment. By this etching, the concave mirror 10 8 and the V groove 109 can be formed on the upper surface of the upper substrate 402 .

  Next, as shown in FIG. 4G, the lower substrate 401 and the upper substrate 402 are bonded in a predetermined positional relationship, and the optical fiber 110 is fixed on the V-shaped groove 109 to complete.

In the above description, the concave mirror 10 8 and the V-shaped groove 109 are formed by the same method as in the second embodiment, but may be performed by mold transfer processing as in the first embodiment.

Further, as shown in FIG. 5, a process of forming a lens 501 on the lower surface of the upper substrate 402 or the upper surface of the lower substrate 401 may be added. The lens 501 may be formed by photolithography and etching, or may be formed by mold transfer processing. In this case, it is possible to use a plane mirror 502 in place of the concave mirror 108. For example, when the flat mirror 502 and the V groove 109 are formed by mold transfer processing, the lens 501 can be formed by the mold transfer processing simultaneously with the formation of the flat mirror 502 and V groove 109.

In the present embodiment as described above, by dividing the substrate up and down, since forming each, for example, an upper substrate having a concave mirror 108 is formed in the pattern transfer process, a lower substrate having a projection 103 By forming by etching, processability and performance of the near-field optical head can be ensured.

Moreover, because it can form a lens 501 at the interface of the upper and lower substrates, it is possible to use a flat mirror 502 instead of the concave mirror 108, it is possible to produce near-field optical head more easily.

  Also in the embodiment described above, a plurality of near-field optical heads can be easily formed simultaneously as in the first and second embodiments. This method enables mass production at a lower cost.

It is sectional drawing which shows the near-field optical head concerning Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing method of the near-field optical head concerning Embodiment 1 of this invention. It is sectional drawing which shows the manufacturing method of the near-field optical head concerning Embodiment 2 of this invention. It is sectional drawing which shows the manufacturing method of the near-field optical head concerning Embodiment 3 of this invention. It is sectional drawing which shows the manufacturing method of the near-field optical head concerning Embodiment 3 of this invention. It is sectional drawing which shows the manufacturing method of the conventional near-field optical head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Substrate 102 Optical minute aperture 103 Protrusion 104 Light shielding film 105 Air bearing surface 106 Concave mirror 107 Mirror surface 108 Concave mirror 109 V groove 201 Frustum 202 Convex part 203 Protective film 301 Substrate 302 Resist 401 Lower substrate 402 Upper substrate 501 Lens 502 Flat mirror 1001 Glass substrate 1002 Lens 1003 Protrusion 1004 ABS
1005 Light-shielding film 1006 Optical minute aperture 1007 Silicon substrate 1008 Light reflecting surface 1009 V-groove 1010 Metal film 1011 Optical fiber

Claims (8)

A near-field optical head comprising: a substrate; a near-field light generating element including a cone or a frustum formed on the lower surface of the substrate; and an air bearing surface that is substantially flush with the near-field light generating element. A method,
A rough shape forming step of forming a rough shape of the near-field optical head by mold transfer processing;
A polishing step of polishing a rough top surface of the cone or frustum formed by the rough shape forming step and a rough top surface of the air bearing surface;
Producing a near-field optical head, wherein the near-field light generating element and the air bearing are formed by a shaping step of etching the outline of the cone or frustum and the outline of the air bearing surface. Method.   2. The method of manufacturing a near-field optical head according to claim 1, wherein in the polishing step, a rough top surface of the cone or frustum and a rough top surface of the air bearing surface are simultaneously polished.   3. The method of manufacturing a near-field optical head according to claim 1, wherein the near-field optical head includes an optical component, and the optical component is formed on an upper surface of the substrate by the outline forming step.   4. The near-field optical head manufacturing method according to claim 3, further comprising a protective film forming step for forming a protective film for maintaining the shape of the optical component on the upper surface of the substrate after the rough shape forming step. Method. A method of manufacturing a near-field optical head according to claim 1 or 2,
The outline forming step includes a step of forming a resist pattern having the shape of an optical component, and transferring the shape of the optical component to the upper surface of the substrate by etching the substrate while etching the resist pattern. A method of manufacturing a near-field optical head. A method of manufacturing a near-field optical head according to claim 5,
A method of manufacturing a near-field optical head, wherein the resist pattern is formed using a gray scale mask. A method of manufacturing a near-field optical head according to claim 5,
A method of manufacturing a near-field optical head, wherein the resist pattern is formed using an electron beam exposure apparatus. A method of manufacturing a near-field optical head according to any one of claims 3 to 7,
The substrate comprises an upper substrate on which the optical component is formed, and a lower substrate on which the near-field light generating element and an air bearing surface are formed,
A near-field optical head comprising: forming the near-field light generating element and the air bearing surface on the lower substrate; forming the optical component on the upper substrate; and bonding the upper substrate and the lower substrate together. Manufacturing method.

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