JP2007042781A - Sub-mount and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sub-mount for mounting an LED element for effectively condensing the light from the LED element, realizing sub-mount having excellent heat radiating property, and manufacturing many sub-mounts at a time under the wafer condition. <P>SOLUTION: An Si substrate (wafer) 4 having a pattern of through-hole 12 forming a sloping surface in the depthwise direction is joined with a glass substrate (wafer) 1 forming a pattern of through-hole electrode 2. An LED element 6A is mounted to the through-hole electrode 2 of the glass substrate 1. The mounting part of the LED element 6A is surrounded by a sloping surface (reflecting film 5 formed at the wall surface of through-hole 12) for reflecting and condensing the light emitted from the LED. Since the processes can be conducted at a time under the wafer condition, low price sub-mounts can be manufactured in large quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a submount, and more particularly to a structure of a submount for mounting a surface emitting optical element such as a semiconductor light emitting element and condensing light efficiently in the light emitting direction of the element, and a manufacturing method thereof.

  Surface emitting optical elements, particularly LEDs (Light Emitting Diodes), have recently been improved in characteristics and are highly expected to be used for wider applications. Conventionally, LEDs are mounted in a plastic case, and microlenses are condensed in the middle of the optical path, or the entire substrate on which LEDs and LEDs are mounted is molded with a transparent resin, and the surface of the resin is a smooth spherical surface. By using the resin as a lens, the light is condensed. Light emitting components mounted with such LEDs are used for, for example, electronic bulletin boards, large video screens, traffic lights, and illumination.

  However, LEDs consume less power than conventional light bulbs and have a longer emission life than light bulbs, so they are expected to be applied in a wide range of fields such as electric lights, indoor lighting, automobile lighting, and backlights for LCD screens. Has been.

  In application to such a product, it is necessary to condense light by causing a large number of LEDs to emit light collectively. The reason is that with one LED element, the intensity of light is still weak compared to a light bulb. However, LED elements molded using conventional resins have a limit in arranging LED elements at high density. In addition, as the output of the LED element increases, the temperature of the LED element easily increases, and the light emission efficiency tends to decrease. Therefore, it is necessary to mount high-power LED elements at high density and efficiently collect light for application to various fields such as lights and lighting.

  A lens is usually used to collect the light. However, if a lens is used for each LED element, the cost increases and the product price increases, and a support for fixing the lens on the LED element is also required.

  An example of a technique related to this type of submount is Patent Document 1.

Japanese Patent Laid-Open No. 5-190973

  The present invention has been made in view of the above situation, and according to the present invention, LED elements can be mounted at high density, light can be collected efficiently, heat dissipation is high, and low. An inexpensive LED submount can be provided.

  According to the present invention, the following submount is provided in order to achieve the above object.

That is, (1) a feature of the submount of the present invention is that a first substrate having a through electrode filled with a conductor;
A second substrate bonded to the first substrate and provided with a through hole whose inner wall forms a light reflecting surface;
A light emitting device in which the through electrode of the first substrate is disposed in the through hole of the second substrate and mounted on the through electrode of the first substrate;
And a power supply terminal that is provided on the first substrate and supplies power to the light emitting element through the through electrode.

(2) a first substrate having a through hole whose inner wall forms a light reflecting surface;
A second substrate bonded to the first substrate;
And a light emitting device mounted on a second substrate located in the through hole of the first substrate.

  (3) More specifically, in the submount described in the above (1) or (2), the first substrate is made of a glass substrate or an Si substrate, and the second substrate is made of a glass substrate. In the case, it is made of a Si substrate, and when the first substrate is a Si substrate, it is made of a glass substrate.

(4) Further, the feature of the method for manufacturing a submount according to the present invention is as follows.
Forming a plurality of through-hole patterns in which a hole diameter is gradually reduced from one surface of the first substrate to the other surface in a two-dimensional matrix at predetermined intervals;
Forming a plurality of through holes in the second substrate in a two-dimensional matrix according to the interval of the through hole pattern of the first substrate;
Forming a through electrode by embedding a conductor layer in the through hole of the second substrate;
Forming an electrode metallization on the through electrode;
Mounting and mounting a light emitting element on one surface of the through electrode;
The second substrate and the first substrate are aligned and bonded together so that the light emitting element pattern mounted on the through electrode is disposed in the through hole pattern of the smaller diameter of the first substrate. Forming a composite by:
And a step of separating a region including at least one through-hole pattern from the composite of the second substrate and the first substrate.

  (5) Further, in the above (4), the first substrate is made of a glass substrate or a Si substrate, the second substrate is made of a Si substrate when the first substrate is a glass substrate, and the first substrate is made of Si. In the case of a substrate, it is characterized by comprising a glass substrate.

  According to the present invention, it is possible to provide a low-cost LED submount that can mount LED elements at high density and can efficiently dissipate heat during light emission. it can.

  In addition, the present invention is a submount for mounting an LED element, and can be applied to various lighting fixtures, traffic light, electric bulletin board, and liquid crystal screen backlight.

  The features of representative embodiments for solving the problems of the present invention are listed below.

  (6) In the submount described in any one of (1) to (3) above, a cross-sectional shape of a through hole in which an inner wall forms a light reflecting surface is bonded to the first substrate and the second substrate. It is characterized by having a shape that is greatly enlarged in the external direction in which light is emitted rather than the size in the part.

  (7) The submount according to any one of (1) to (3), wherein the inner wall is formed with a metallization on an inner surface of a through hole forming a light reflecting surface.

  (8) In the submount described in any one of (1) to (3) above, the cross-section of the through hole is a curved shape (for example, a parabolic shape). This feature is, for example, that the inner wall of the through hole is a curved surface that smoothly narrows the inner diameter of the through hole from one side of the main surface of the substrate to the other, or a virtual line that extends between the main surfaces. It is realized by making it a paraboloid.

  (9) In the submount described in any one of (1) to (3) above, a smooth surface is formed by applying resin to the inner surface of the through hole.

  (10) In the submount described in (6) above, the metallization includes Al or an Al alloy film.

  (11) In the submount as described in (1) or (3) above, the through electrode on the surface of the first substrate provided with the through electrode on the opposite side to the joint surface with the second substrate provided with the through hole The metallization which is not electrically connected with the said penetration electrode is provided in a part other than these.

  (12) In the submount described in (1) to (3) and (6) to (10), the first substrate and the second substrate are bonded by anodic bonding.

Embodiments of the present invention will be described in detail below with reference to the drawings.
<Example 1>
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a minimum structural unit of an LED submount 100 assembled in the state of a glass substrate and a Si wafer, and shows a cross-sectional view taken along line XX ′ of FIG. Accordingly, the illustrated submount 100 shows a structure of one submount 100 cut out by dicing from a substrate on which a large number of submounts are collectively formed. 2 is a plan view of the LED submount of FIG. 1, and FIG. 3 is a perspective view of the submount of FIG.

  A through hole is formed in the glass substrate 1, and a through electrode 2 filled with a conductor is formed there. An electrode metallized 3A is formed on the back surface of the glass substrate 1 and is used for connection to an external electrode. The glass substrate 1 is bonded to the Si substrate 4 having the through hole 12, and the reflective film 5 is formed on the inner wall of the through hole 12 of the Si substrate 4.

  On the through electrode 2 of the glass substrate 1 located in the through hole 12 of the Si substrate 4, an electrode metallization 3B for connecting the LED element is formed, and the LED element 6A is mounted on the electrode metallization 3B and the LED. One electrode of the element 6A is connected to the electrode metallization 3B, and the other electrode is electrically connected to another adjacent through electrode 2 by wire bonding 7.

  In this example, with respect to one through hole 12 of the Si substrate 4, five through electrodes 2 are provided in the glass substrate 1 so as to correspond to one pattern. Of the five through electrodes 2, the central through electrode 2 serves as a terminal for supplying power to one electrode of the LED element 6A mounted on the four surrounding through electrodes 2.

  As shown in the drawing, the diameter of the through hole 12 of the Si substrate 4 is gradually smaller in the depth direction from the surface, and since the LED element 6A is disposed at a position where the diameter is small, the light emitted from the LED element 6A is transmitted to the outside. It has a structure that can collect and radiate efficiently.

  In the submount 100 of the present embodiment, four LED elements 6A are mounted on the through electrode 2 of the glass substrate 1 located in the through hole 12 of the Si substrate 4, but the LED elements are more dense. By arranging, it is possible to mount many LED elements in one submount.

  The LED element 6A mounted and connected on the through electrode 2 can generate light of various colors by arranging LEDs of the same emission color or three colors such as RGB (Red, Green, Blue). Is also possible. In this case, in the structure as shown in FIG. 2, one of the LED mounting portions may be left as it is without mounting the LED element 6A. Further, the number of through electrodes 2 may be increased, and a larger number of LED elements 6A may be mounted, or the through electrode 2 may be used as one and the submount may be mounted with one LED element.

  What is important in this embodiment is that the LED element 6A provided on the glass substrate 1 is exposed in the through hole 12 of the Si substrate 4, and the reflective film 5 provided on the wall surface of the through hole 12 emits from the LED element 6A. That is, the light is effectively reflected and condensed and emitted to the outside of the through hole 12.

  Next, the manufacturing process will be described. As shown in FIG. 4, in order to form the through-electrodes 2 using sandblasting on the glass substrate 1 in a wafer state, through-hole patterns are formed in a matrix at two-dimensionally constant pattern intervals. This through hole is filled with a conductive resin, solder, or the like, or plated with a metal such as Cu or Ni to form the through electrode 2.

  Although not shown in the figure because it is complicated, in the subsequent steps, an electrode metallization 3A is formed on the back surface of the glass substrate 1, and an electrode metallization 3B for LED element connection is formed on the surface side to be joined to the Si substrate 4. .

  The method includes a Ti layer for obtaining good adhesion to glass, a Pt layer serving as a barrier layer for protecting the Ti layer, or a Ni layer, and an Au layer for preventing surface oxidation. It is formed using a sputtering method or a vapor deposition method. Next, a mask pattern having the same shape as that of the metallized pattern is formed using a photoresist, and the metallization of other portions is removed by milling. Thereafter, washing is performed to remove the resist, whereby a desired metallized pattern is formed.

  As another metallized pattern forming method, a so-called lift-off process in which a mask pattern is first formed and then metallized is formed to remove the metallized pattern on the mask is also applicable.

  On the other hand, anisotropic wet etching can be used as a method for forming the through hole 12 in the Si substrate 4. First, as shown in FIG. 4, a mask pattern in which a portion for forming a through hole is opened is formed on a Si wafer having a (100) plane as an upper surface. Next, when processing is performed by wet etching, it becomes possible to form the closest packed (111) surface as an inclined surface by appropriately controlling the etching rate. By performing this etching until it penetrates, it is possible to form the through-hole 12 having slopes on all sides.

  Although not shown in FIG. 4, the reflective film 5 is formed in the through hole 12. Metallization can be used for this reflective film. The metallization is preferably a mirror surface, but may have some unevenness. For metallization, in order to improve adhesion to the Si substrate 4, Ti metallization is formed first, and Al metallization or the like is formed thereon. In addition to this, when it is desired to change the color tone of the light emitted from the LED element, it is possible to use a metal whose reflectance changes easily depending on the wavelength of the light.

  As shown in FIG. 5, the glass substrate 1 and the Si substrate 4 processed as described above are exposed in the through hole 12 of the Si substrate 4 so that the through electrode pattern 2 provided on the glass substrate 1 is exposed. In addition, the alignment is preferably performed so that the pattern 2 of the four holes of the glass substrate 1 comes to the center (focal point) of the through hole 12 of the Si substrate 4, and the two substrates are joined to form a composite. In joining, a method called anodic joining is suitable, but the joining method is not necessarily limited to anodic joining. Besides anodic bonding, metallization is formed on the glass substrate 1 and the Si substrate 4 and bonded by soldering or without forming the metallization, and low melting point glass is supplied to the bonding surface by a method such as printing. It is also possible to join using. However, here, the description will focus on anodic bonding, which is often used as a bonding method between glass and Si.

  Anodic bonding is a bonding technique that can be applied mainly to bonding of glass and Si or metal. In recent years, this is a technology that is actively used in a field called MEMS (Micro Electro Mechanical Systems).

  The principle of anodic bonding is briefly described below. Glass and Si are superposed and heated to several hundred degrees. In this state, a voltage is generally applied so that the glass side is negative and the Si side is positive. As a result, a strong electric field is generated in the glass, and cations having a small radius such as Na contained in the glass are forcibly diffused to the negative electrode side by this electric field. It is said that a deficient layer is formed. Since the cation-deficient layer is negatively charged, a stronger electrostatic attractive force is generated in the vicinity of the bonding interface. This electrostatic attractive force causes the glass and Si to adhere firmly. At the same time, oxygen contained in the glass reacts with Si to form an oxide at the interface, thereby chemically bonding and obtaining a strong bond.

  The anodic bonding needs to be performed at a temperature lower than the heat resistant temperature of the material filled in the through electrode 2. When the conductive resin is filled, 200 to 250 ° C. is preferable although it depends on the type of the resin. When the solder is filled, it is necessary to carry out at a temperature below the melting point of the solder, and when filled with plating, the temperature is below the melting point of the plating metal and does not melt the glass.

  For example, when Au—Sn solder is filled, the bonding may be performed at a melting point of 280 ° C. or lower of the Au—Sn solder, and when it is filled with Cu plating or the like, the melting point is 1084 ° C. or lower. Since there is a problem of heat resistance of glass, about 400 ° C. is preferable.

  As described above, the glass substrate 1 and the Si substrate 4 are joined, and the LED element 6A is mounted or divided into minimum units as shown in FIG. 1 by dicing or the like. Either the LED element mounting process or the splitting process may be performed first, but if LED element mounting and wire bonding are performed in a batch on the wafer, the parts transportation time in the mounting process is reduced and productivity is improved. Can be made.

  When the submount 100 is divided into minimum units by dicing, it is possible to cover the LED element 6A on the Si substrate 4 with a tape or the like for protecting the LED element 6A from cooling water for dicing. On the other hand, if the division by dicing or the like is performed first, there is a merit that there is no need to prevent the cooling water during dicing from being applied to the LED element, but in the LED element mounting process, individual substrates are transferred. There is a demerit that time to do is generated. Which method is to be selected can be selected according to the production at that time, the state of the equipment, and the like.

  The reason why the LED element 6A is mounted on the conductive through electrode 2 and the electrode metallization 3B thereon is to obtain an electrical connection and to efficiently dissipate heat generated by the LED element. If the LED element generates a relatively small amount of heat, a conductive resin or the like can be used as a filling material for the through electrode. However, if the amount of heat generated is large, a metal material such as solder or plating can be used directly. A filling structure is desirable.

  As described above, the LED submount assembled in the wafer state, the LED element mounting, and the division by dicing are completed as shown in FIGS. By adopting such a configuration, as shown in FIG. 8, the light traveling in the lateral direction of the LED element can be reflected upward by the reflection film 5, and the light can be efficiently condensed upward.

  A further developed form based on the structure of the first embodiment will be described below. In general, the anodic bonding is often performed at around 400 ° C., and the bonding property may be insufficient at around 200 ° C. In such a case, as shown in FIG. 6, Ti / Al metallization 8 for promoting bonding can be sequentially formed on the Si substrate 4 side to promote bonding. The reason is that the strength of anodic bonding is increased because the oxidation reaction between oxygen in the glass and the element on the other side is the main. By forming Al metallization that is easier to oxidize than Si on the bonding surface, glass and Al metallization sufficiently react even at a low temperature, and the bonding strength can be improved.

  The electrode metallization 3 in FIGS. 1 and 2 can be made slightly smaller. In this case, the bonding surface with the Si substrate 4 can be inspected through the glass substrate 1 even at a visual level. When anodic bonding is performed, a portion where a void or the like remains is an unbonded portion, and this portion often appears white due to light reflection. On the other hand, there is an advantage that the joint can be easily inspected because the reflection of light is different and often looks black in a portion where the joint is good.

  In addition, as shown in FIG. 7, the electrode metallization 3 can be made smaller, and further, the voltage application metallas 9 at the time of anode connection can be formed. In this structure, when voltage is applied with the voltage application metallization 9 minus and the Si substrate 4 plus, the voltage is concentrated in the glass substrate 1 sandwiched between the electrode application metallization 9 and the Si substrate 4, and the glass A strong electric field can be generated in the substrate 1. As a result, the diffusion of cations is likely to proceed even at a relatively low temperature, and the joining proceeds smoothly even at a low temperature.

  As described above, by processing and bonding the glass substrate 1 and the Si substrate 4 in a wafer state, a large amount of LED submounts can be manufactured in a lump and a low-cost LED submount can be provided. it can.

A method for further increasing the light collection efficiency upward based on the embodiments described so far will be described below. As shown in FIG. 9, anisotropic etching is performed without penetrating the Si wafer, and the resin 10 is applied to the side and bottom surfaces of the holes and cured. Next, by polishing the back surface of the Si substrate, a Si substrate having a smoothly curved through hole can be formed. By making the inside of the through hole 12 a smooth reflecting surface with the resin 10 and further forming the reflecting film 5 on the surface, as shown in FIG. it can.
<Example 2>
A second embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 10 and 11, unlike the first embodiment, the glass substrate 1 is processed to form a reflection surface of light from the LED element 6A. That is, the through hole 12 is provided in the Si substrate 4 in the first embodiment, whereas the through hole 12 is provided in the glass substrate 1 in the second embodiment. In this embodiment, the glass substrate 1 is processed by a known sand blasting method as a method of providing the through holes 12 in the glass substrate 1.

  In sandblasting, a circular resist mask pattern having an opening diameter of about 2 mm is first provided on the glass substrate 1, and sand is sprayed on the exposed glass surface to selectively process it.

  In sandblasting, the hole diameter on the opposite side when penetrating is usually smaller than the hole diameter on the surface where sand hits. That is, the hole diameter decreases stepwise in the depth direction of the hole. This is presumed to be because the number of sand hits decreases as the hole becomes deeper. In this embodiment, a curved surface is formed in the cross section of the hole by gradually decreasing the momentum of the sand applied as the hole becomes deeper. Adjust the momentum of the sandblast so that this curved surface draws a parabola as much as possible. The reason for making the curved surface a parabola is to send light emitted from the LED upward as efficiently as possible, but when the light emitted from the LED is sufficiently strong, it is not always necessary to process it into a curved surface. A reflective film 5 is formed on the curved surface as in the first embodiment.

  The glass substrate 1 and the Si substrate 4 are aligned and bonded to each other so that the LED element mounting portion of the Si substrate 4 is in the through hole 12 of the formed glass substrate 1. By mounting the LED element 6A inside the through hole 12 of the glass substrate 1, the light emitted from the LED element is reflected by the reflective film 5 and condensed upward.

  The formation of the reflective film 5 will be described in detail with reference to FIG. In order to improve the light collection efficiency as much as possible, it is necessary to reduce the roughness of the curved surface of the glass substrate 1 caused by sandblasting. In such a case, the roughness can be reduced by reducing the sand particle size of the sandblast or slightly etching the ground surface by sandblasting with hydrofluoric acid. In order to form a more drastically smooth curved surface, a resin 10 having heat resistance and low viscosity can be applied onto the curved surface as shown in FIG. As a result, the resin 10 enters the rough recessed portion 11 (V groove), and the unevenness can be reduced. From this, a Ti metallization 5a is formed to improve adhesion, and finally an Al metallization 5b is formed to make the reflective film 5.

  In order to form a smooth curved surface by applying a resin, as another method, as shown in FIG. 13, holes are formed by a method such as sandblasting without penetrating the glass substrate 1, and the resin 10 is formed inside. A glass with a through-hole having a smooth curved surface in a first processing step of applying a curved surface to form a curved surface and a second processing step of polishing the back surface of the glass substrate 1 after sufficiently curing the resin A substrate can be produced.

  A wiring drawing structure and a dividing method in this embodiment will be described with reference to FIGS. FIG. 14 is a diagram illustrating a cross section taken along line A-A ′ of FIG. 15. As shown in FIG. 15, the Si substrate 4 is processed by anisotropic etching. An etched portion in the A-A ′ cross section that is lower than the mounting surface of the LED element 6 </ b> A is referred to as a groove 13.

  An electrode metallization 3B is formed continuously from the LED element mounting portion along the groove 13. The glass substrate 1 and the Si substrate 4 are bonded to each other on the surface of the Si substrate 4 that is not etched and other than the groove 13 and at a portion other than the through hole 12 of the glass substrate 1.

  In the following, a method of dividing the electrode metallized 3B continuous with the LED element 6A by dicing leaving wire bonding from the outside will be described.

  Dicing is performed twice. First, as shown in FIGS. 15 and 16, only the glass substrate 1 is diced at the first dicing position without cutting the Si substrate 4. Therefore, FIG. 16 is a diagram illustrating a cross section at the time when the first dicing is completed.

Next, as shown in FIG. 16, the Si substrate 4 is cut by the second dicing. As described above, the electrode metallization 3B is formed on the Si substrate 4, and the glass substrate 1 does not exist on the electrode metallization 3B. A structure capable of wire bonding can be formed on the electrode metallization 3B.
<Example 3>
A third embodiment of the present invention will be described with reference to FIG. In FIG. 17, through holes are formed in the Si substrate 4 by a method such as sand blasting, and the through holes 2 are filled with a conductive paste, solder, metal plating, or the like. By mounting the LED element 6 </ b> A on the electrode metallization 3 </ b> B on the through electrode 2, the heat dissipation can be improved as compared with the second embodiment of FIG. 14.
<Example 4>
A fourth embodiment of the present invention will be described with reference to FIG. In FIG. 18, the Si substrate 4 is sandblasted to form a curved surface similar to that in Examples 2 and 3, and is bonded to the glass substrate 1 with the through electrode 2. To smooth the ground surface by sandblasting, the same method as in FIG. 12 can be used.

It is sectional drawing of the submount 100 shown in Example 1 of this invention. It is a top view of the submount shown in Example 1 of this invention. It is a perspective view of the submount shown in Example 1 of the present invention. It is a perspective view of the glass substrate and Si substrate which are shown in Example 1 of this invention. It is a perspective view which combined and integrated the glass substrate and Si substrate which were shown in Example 1 of this invention, and was set as the composite. It is sectional drawing of the submount shown in Example 1 of this invention, and provides the metallization 8 in the joint surface of the glass substrate 1 and Si substrate 4. FIG. It is sectional drawing of the submount shown in Example 1 of this invention, and the metallizing 9 for voltage application at the time of anode connection is provided in the back surface of the joint surface of the glass substrate 1. FIG. It is sectional drawing of the submount shown in Example 1 of this invention, and shows the optical path of the emitted light from LED element 2A. It is sectional drawing which shows the process of forming the through-hole 12 in Si substrate 4 in Example 1 of this invention. It is sectional drawing of the submount 100 shown in Example 2 of this invention. It is a top view of the submount 100 shown in Example 2 of this invention. It is principal part sectional drawing of the through-hole 12 of the glass substrate 1 which comprises the submount 100 shown in Example 2 of this invention. It is sectional drawing which shows the process of forming the through-hole 12 in the glass substrate 1 in Example 2 of this invention. It is principal part sectional drawing of the submount 100 shown in Example 2 of this invention. The perspective view of the submount 100 of Example 2 of this invention is typically shown. It is sectional drawing which shows the dicing process at the time of forming the submount 100 of Example 2 of this invention. It is a fragmentary sectional view of submount 100 shown in Example 3 of the present invention. It is a fragmentary sectional view of submount 100 shown in Example 4 of the present invention.

Explanation of symbols

1 ... Glass substrate,
2 ... through electrode,
3A: electrode metallization for connection to the outside,
3B: electrode metallization for connection with LED elements,
3C: electrode metallization for wire bonding of LED elements,
4 ... Si substrate,
5 ... reflective film,
6A ... LED element,
6B ... Light emitting part of the LED element,
7 ... Wire bonding,
8 ... Ti / Al metallization,
9 ... Metallization for voltage application,
10 ... heat resistant resin,
11 ... V groove,
12 ... Through hole by anisotropic etching of Si substrate,
13 ... Groove,
100 ... Submount.

Claims (12)

A first substrate having a through electrode filled with a conductor;
A second substrate bonded to the first substrate and provided with a through hole whose inner wall forms a light reflecting surface;
A light emitting device in which the through electrode of the first substrate is disposed in the through hole of the second substrate and mounted on the through electrode of the first substrate;
A power supply terminal provided on the first substrate and supplying power to the light emitting element via the through electrode;
Submount characterized by comprising A first substrate having a through hole whose inner wall forms a light reflecting surface;
A second substrate bonded to the first substrate;
A light emitting device mounted on a second substrate located in the through hole of the first substrate;
Submount characterized by comprising   3. The submount according to claim 1, wherein the first substrate is made of a glass substrate or a Si substrate, the second substrate is made of a Si substrate when the first substrate is a glass substrate, and the first substrate is made of A submount comprising a glass substrate in the case of a Si substrate.   4. The submount according to claim 1, wherein a cross-sectional shape of a through hole in which an inner wall forms a light reflecting surface is lighter than a size at a joint portion between the first substrate and the second substrate. A submount characterized by having a shape greatly enlarged in the external direction from which the light is emitted.   4. The submount according to claim 1, wherein metallization is formed on an inner surface of a through hole in which the inner wall forms a light reflecting surface.   4. The submount according to claim 1, wherein a cross-sectional shape of the through hole has a curved shape. 5.   4. The submount according to claim 1, wherein a smooth surface is formed by applying a resin to an inner surface of the through hole. 5.   6. The submount according to claim 5, wherein the metallization includes an Al or Al alloy film.   The submount according to claim 1 or 3, wherein the portion other than the through electrode on the surface of the first substrate on which the through electrode on the side opposite to the joint surface with the second substrate on which the through hole is provided is provided on the submount. A submount comprising a metallization that is not electrically connected to a through electrode.   10. The submount according to claim 1, wherein the first substrate and the second substrate are bonded by anodic bonding. Forming a plurality of through-hole patterns in which a hole diameter is gradually reduced from one surface of the first substrate to the other surface in a two-dimensional matrix at predetermined intervals;
Forming a plurality of through holes in the second substrate in a two-dimensional matrix according to the interval of the through hole pattern of the first substrate;
Forming a through electrode by embedding a conductor layer in the through hole of the second substrate;
Forming an electrode metallization on the through electrode;
Mounting and mounting a light emitting element on one surface of the through electrode;
The second substrate and the first substrate are aligned and bonded together so that the light emitting element pattern mounted on the through electrode is disposed in the through hole pattern of the smaller diameter of the first substrate. Forming a composite by:
Separating the region including at least one through-hole pattern from the composite of the second substrate and the first substrate. 12. The method of manufacturing a submount according to claim 11, wherein the first substrate is made of a glass substrate or a Si substrate, and the second substrate is made of a Si substrate when the first substrate is a glass substrate. When the substrate is a Si substrate, it is made of a glass substrate.

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