JP4492219B2 - Support substrate, method of forming semiconductor device using the support substrate, and semiconductor device - Google Patents

Description

  The present invention is a light-emitting device such as a light-emitting diode, for example, a light-emitting device in which a large amount of electric power is input and a high-power light-emitting element is housed, and has low thermal resistance that can be used for home lighting and in-vehicle lighting. The present invention relates to a light emitting device with excellent heat dissipation. In particular, the present invention relates to a method for forming a support substrate for mounting a semiconductor element and a semiconductor device using the support substrate.

  A semiconductor light emitting element such as a light emitting diode or a laser diode can be used as a light source of a light emitting device. Furthermore, in recent years, a light-emitting device that emits white mixed color light by combining a semiconductor light-emitting element and a fluorescent material that absorbs light from the semiconductor light-emitting element to emit light has been put into practical use. It has been used for displaying lights. And it is anticipated that it will be widely used for indoor lighting, in-vehicle lighting, etc. due to its high luminous efficiency and high brightness.

  The semiconductor light-emitting elements in these light-emitting devices generate heat with light emission, and raise the temperature of the entire light-emitting device. Therefore, by using ceramics with high heat resistance as a material for the support member of the semiconductor element, the heat of the light emitting element can be quickly and efficiently radiated. A support for a semiconductor element made of such a ceramic material is formed, for example, by laminating a plurality of unfired ceramic sheets, forming a recess for housing the semiconductor element, and then firing. In such a light-emitting device that houses a light-emitting element in a recess, part of the light from the light-emitting element is emitted in the direction of the side wall of the recess, so that the inner wall surface of the recess is tapered or reflects light from the light-emitting element. It is necessary to coat the inner wall surface with a metal having a function (for example, see Patent Document 1).

  On the other hand, there is one in which conductor wiring is applied to a fired flat ceramic substrate to form a support substrate on which a semiconductor element is mounted. For example, the conductor wiring in the support substrate disclosed in Patent Document 2 is provided with a mask pattern made of a photosensitive material on the conductive material applied to the ceramic substrate, and the unmasked conductive material is removed by sandblasting. After that, the mask pattern is removed.

JP 10-215001 A Japanese Patent Laid-Open No. 7-202381

  However, the support substrate in which the conductor wiring is applied to the above-described flat ceramic substrate has a complicated process of forming the support member. That is, a photosensitive material that becomes a mask for sandblasting the conductive member is required, and a patterning process for the photosensitive material and a mask removal process after sandblasting are required. Therefore, further simplification of the formation process is desired.

  In addition, in order to provide an auxiliary member such as a submount for mounting a semiconductor element on a support substrate in which conductor wiring is applied to a flat ceramic substrate, an auxiliary member formed in a separate process is used as the support member. A process of bonding is required, and workability in the manufacturing process of the semiconductor device is reduced. Furthermore, the bonded auxiliary member cannot smoothly radiate heat from the semiconductor element in the direction of the support member because the thermal conductivity is different in the adhesive portion.

  In view of the above, an object of the present invention is to provide a semiconductor device in which a support member is formed with good workability using ceramics as a material, and further has good heat dissipation.

In the method for forming a supporting substrate for mounting a semiconductor element having a pair of positive and negative electrodes on the same side, in order to achieve the above object, a method of forming the support substrate according to the present invention, positive and negative of the semiconductor element of the surface of the ceramic substrate A first step of forming a first pattern with a conductive member in a region facing each of the pair of electrodes, and a sandblasting process on the surface on which the first pattern is formed using the first pattern as a mask by applying, forming a second step of forming a recess in the roughened ceramic green body, to the recess, so as to connect the first pattern and electrically, the second pattern by a conductive member And a third step. If comprised in this way, a support member can be formed with ceramics as a material with sufficient mass productivity.

  Moreover, it is preferable that the inclination of the side wall surface is 45 to 80 degrees in the ceramic ground surface exposed by the sandblasting process. Moreover, it is preferable to perform sandblasting with an abrasive having an average particle size of 7 to 30 μm. Thereby, it can process without applying a stress to a ceramic substrate, and it can be set as a highly reliable support substrate.

Further, in a method for forming a semiconductor device having a semiconductor element having a pair of positive and negative electrodes on the same surface side and a support substrate on which the semiconductor element is mounted, the method for forming a semiconductor device according to the present invention is provided to achieve the above object. The first step of forming a first pattern with a conductive member on the first region of the surface of the ceramic substrate facing the pair of positive and negative electrodes of the semiconductor element, and the first pattern is formed. the surface, by a sandblasting process is performed said first pattern as a mask, a second step of forming a recess in the roughened ceramic green body, the said recess, said first pattern and electrically Yes a third step of forming a second pattern by a conductive member to connect, and a fourth step of electrically connecting the first pattern on SL and the semiconductor element That. When a semiconductor device is formed in this way, a semiconductor device with high mass productivity and high heat dissipation can be formed.

  Moreover, it has further the 5th process of fitting and fixing the edge part of an optical member to the uneven | corrugated shape of the said support substrate. Thereby, the mounting precision with respect to the support substrate of an optical member can be improved.

  In addition, the semiconductor element has a pair of positive and negative electrodes on the same surface side, and the electrodes are mounted on the upper surface of the convex portion formed by the sandblasting process via a conductive material, and connected to the first patterning. It is preferred that Thereby, a semiconductor device excellent in heat dissipation and optical characteristics can be formed without adhering and mounting a separate auxiliary member such as a submount.

  The semiconductor element is hermetically sealed by the support substrate and the optical member. The optical member is preferably fixed with an insulating adhesive. Thereby, favorable airtight sealing can be performed.

  Moreover, it is preferable that the inclination of the side wall surface of a recessed part shall be 45 to 80 degree | times by the said sandblasting process. Moreover, it is preferable to perform sandblasting with an abrasive having an average particle size of 7 to 30 μm. Thereby, it can process without applying a stress to a ceramic substrate, and it can be set as a highly reliable support substrate.

In addition, a semiconductor device according to the present invention includes a semiconductor element having a pair of positive and negative electrodes on the same surface side , and a support substrate having a conductor wiring electrically connected to the semiconductor element and mounting the semiconductor element. an apparatus, the supporting substrate is a ceramic substrate, the conductor wire, the first conductor wiring region having a first region are electrically connected via the electrode and the conductive member of the semiconductor element If, have a and the first region and electrically second conductor wiring region for connecting the said second conductor wiring region is sandblasted on the supporting substrate to the first conductor wiring region as a mask It is formed in the recessed part of the roughened ceramic base formed by giving . Furthermore, the surface roughness of the second conductor wiring region is smaller than the surface roughness of the first conductor wiring region.

  Thereby, an optical member such as hemispherical glass can be firmly bonded to the surface of the support substrate roughened by sandblasting. Further, since the adhesion of the metal material is improved when forming the second conductor wiring region, patterning of the second conductor wiring region by sputtering or the like is facilitated. In addition, the surface of the first region that is electrically connected to the semiconductor element via the conductive member and the second region that supplies power to the semiconductor device from the external electrode are roughened by receiving sandblasting as a mask. It is in close contact with a conductive member such as solder. As described above, when the portion connected to the conductive member is a rough surface, the electrical connectivity between the constituent members of the semiconductor device is improved, and a highly reliable semiconductor device can be obtained.

  The support substrate has a recess into which the end of the optical member is fitted, and the upper surface of the side wall of the recess serves as the first conductor wiring region. Thereby, the edge part of an optical member is positioned by a recessed part side wall, and the mounting | wearing property of the optical member with respect to a support substrate improves.

  Moreover, it is preferable that the upper surface of the support substrate used as said 2nd area | region is made into the substantially same surface as the edge part upper surface of the said optical member. Thereby, the light from the semiconductor light emitting element can be emitted from the portion having the optical function of the optical member without being blocked by the end portion of the optical member, and a light emitting device having excellent light extraction efficiency can be obtained.

By the formation method of the present invention, a semiconductor device with improved heat dissipation can be obtained with high productivity.
[Best Mode for Carrying Out the Invention]

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the support substrate, the semiconductor device, and the manufacturing method thereof for embodying the technical idea of the present invention, and the present invention is not limited to the following. Further, the size and positional relationship of the members shown in each drawing are exaggerated for clarity of explanation.

  A method of forming a support substrate according to the present invention includes a step of patterning with a conductive member on a front surface of a flat plate substrate made of ceramics, and cutting a region other than the region where the conductive member is disposed by sandblasting, and sandblasting. Forming a conductive wiring pattern by sputtering, printing, plating, or the like on the surface of the ceramic substrate that is cut and exposed by sandblasting so as to be connected to the pattern of the conductive member on the front surface of the ceramic substrate that has not been processed; At least. This eliminates the need for a step of removing the sandblasting mask pattern, and allows the support substrate to be formed with high productivity. Further, the upper surface of the convex portion formed by sandblasting can be used as a mounting surface of the semiconductor element. Furthermore, by sandblasting the mounting surface with a predetermined pattern, the processed part can be used as a positive / negative insulating separation part of the conductor wiring. Furthermore, the uneven shape of the ceramic substrate formed by sandblasting is used as the mounting surface of the optical member, and the uneven shape is used for alignment of the optical member. Thereby, the mounting precision of the optical member with respect to a support substrate can be improved.

  For example, when a light emitting device is mounted on a support substrate to form a light emitting device, it is necessary to arrange the light emitting device at a position higher than the main surface of the flat support substrate in order to effectively use the light emitted from the side surface of the light emitting element. is there. Therefore, in the conventional light emitting device, the light emitting element is sometimes mounted on the support substrate via an auxiliary support member called a submount. In such a conventional light emitting device, it is necessary to fix the submount substrate to the support substrate, and an insulating adhesive, Ag paste, or brazing material has been used for fixing.

  However, the insulating adhesive has poor thermal conductivity, and the brazing material itself has conductivity, which causes the wiring inside the light emitting device to be complicated. Further, when the submount substrate is bonded to a predetermined position of the support substrate, positioning is difficult and mounting accuracy is poor.

  Therefore, the present invention makes it possible to eliminate the step of providing an auxiliary member in a separate step by using the uneven-shaped convex portion generated by sandblasting the ceramic substrate as a substitute for the submount.

  Moreover, the side wall surface of the recessed part formed by the sandblast process becomes a taper shape normally. Accordingly, among the concavo-convex shape, the convex portion has a tapered shape such that the cross-sectional area gradually increases in the direction opposite to the semiconductor element from the mounting surface of the semiconductor element. Thereby, the heat dissipation from the semiconductor element mounted on the upper surface of the convex portion can be improved.

  Further, in the light emitting device, the light emitting element can be mounted at a position higher than the mounting surface of the optical member by using the upper surface of the convex portion as the mounting surface of the light emitting element. Therefore, the light emitted from the side surface of the light emitting element is not blocked by the portion where the optical member is fixed (for example, the edge of the spherical lens or the adhesive for fixing the lens to the support substrate), and the optical characteristics. It can be set as the light-emitting device excellent in.

  It can be set as the semiconductor device which has the support substrate concerning this invention, and the optical member which controls the light distribution of the semiconductor element mounted in this support substrate. Here, the shape of the optical member is various in order to control the light condensing property to the light receiving element and the light distribution property of the light from the light emitting element. An example of such an optical member is a lens in which a part of the optical member is hollow (hollow) and has a uniform thickness and a dome shape. At this time, it is preferable that an inert gas such as air or nitrogen gas is sealed in the hollow portion. In particular, by enclosing an inert gas such as nitrogen gas, it is possible to prevent deterioration of the quality of the conductive adhesive containing metal particles in order to improve heat dissipation. For example, migration of Ag paste used as an adhesive for the protective element can be prevented, and a highly reliable light-emitting device can be obtained. The semiconductor element is housed in a hollow portion and hermetically sealed by the optical member and the support substrate. Therefore, the light emitted from the light emitting element is emitted from the light emission observation surface of the lens using the inert gas as a medium. Thereby, it is possible to prevent the light source (light emitting element) housed in the hollow portion as a light emitting device from apparently becoming large. That is, when glass, resin, or the like is not hollow, they themselves function as a convex lens, the apparent light source size is increased, and the light emitting surface for other optical members such as a reflecting surface is increased. In order to realize a predetermined light distribution characteristic using this, a larger optical system is required. On the other hand, by making it hollow, the light emitting surface for other optical members can be made relatively small, the light distribution can be more easily controlled, and excellent light distribution can be obtained.

  It is preferable that the optical member is positioned and mounted by the uneven shape of the ceramic substrate generated by sandblasting. The specific material of the optical member is preferably a material suitable for molding of the optical member, such as hard glass, soft glass such as soda lime glass, polycarbonate, acrylic resin, and epoxy resin. With such a material, the optical member is molded into various shapes such as a spherical lens so that the light from the light emitting element can be optically controlled. Moreover, it is preferable to fix the optical member and the ceramic substrate with an insulating adhesive made of epoxy or polyimide resin. Thereby, the hollow part of an optical member can be made into a favorable airtight state, and the reliability of a light-emitting device can be improved.

  The light-emitting element having a pair of positive and negative electrodes on the same surface side is preferably flip-chip mounted so that the electrodes are connected to the conductor wiring of the support substrate via a conductive material. The conductive material can be Au or solder. This eliminates the need for a conductive wire for connecting the electrode of the light emitting element and the conductor wiring, and thus a light emitting device with high heat dissipation and high reliability can be obtained. In addition, since the conductive wire does not block light from the light emitting element, a light emitting device having excellent optical characteristics can be obtained. Hereinafter, a method for forming a semiconductor device in this embodiment and each structure of this embodiment will be described in detail.

(First pattern formation process)
This step is a step of forming, on the ceramic substrate, a pattern that serves as a sandblast mask and also serves as a conductor wiring of the semiconductor support substrate using a conductive member.

The material of the ceramic substrate can be AlN, Al ₂ O ₃ , Si, SiC, SiO ₂ , or BeO having excellent thermal conductivity. The material of the conductive member is preferably a metal selected from Au, Ag, Al, Cu and Sn or an alloy thereof. Here, in consideration of adhesion between these metals and the ceramic substrate, the metal material may be laminated using a metal such as Ni or Pt as an underlayer.

  The pattern in this step is formed by a method such as sputtering, vapor deposition, plating, or a combination of one or more of them using a predetermined mask pattern. Moreover, the conductor wiring given by baking the resin binder in a conductor paste can also be made into a 1st pattern.

(Sandblasting process)
This step is a step of removing a portion of the ceramic material that has not been subjected to the first pattern by sandblasting. That is, in this step, the surface of the ceramic substrate on which the first pattern serving as a mask is formed is sprayed with an abrasive simultaneously with air from a sandblast nozzle to remove the ceramic material exposed from the first pattern. It is.

  Here, the specific material of the abrasive is selected according to the hardness of the ceramic substrate, and is preferably alumina, silica, silicon carbide, or a mixture containing at least one of them. Furthermore, it is preferable that the abrasive is in the form of particles and the particle size is 7 to 30 μm. The inclination of the side wall surface of the recess is preferably 45 to 80 degrees. Accordingly, sandblasting can be performed without applying stress to the ceramic substrate, and a highly reliable semiconductor device can be obtained.

  Further, the surface of the first pattern 2 used as a mask for sandblasting is roughened by receiving the spray of the abrasive. The first pattern 2 can be connected to an external electrode terminal via solder. Or it connects with the electrode of a semiconductor element via a bump or a conductive wire. By appropriately adjusting the surface roughness of the first pattern 2, the wettability between the metal material of the first pattern and the solder or bump is improved, and a semiconductor device having excellent reliability can be obtained. Thus, by sandblasting using a pattern that can also be used as a conductor wiring as a mask, the process of removing the mask and another process of roughening the surface of the conductor wiring are not required. A semiconductor device with improved mass productivity can be obtained.

(Second pattern formation step)
In this step, a second pattern serving as a conductor wiring for supplying power to the semiconductor element is applied to the ground surface of the ceramic substrate cut by sandblasting. Furthermore, the second pattern applied in this step is electrically connected to the first pattern used as a mask for the sandblasting step. Then, the second pattern applied in this step can be connected to a semiconductor element as a conductor wiring, and the first pattern used as a mask in the sandblasting process can be used as a conductor wiring for connecting to an external electrode. Also, other semiconductor elements can be mounted using the second pattern as a conductor wiring. For example, in order to protect the semiconductor light emitting element from destruction due to overvoltage, a chip-shaped Zener diode can be connected to a conductor wiring with a conductive adhesive (for example, a conductive wire, Ag paste) and mounted on a support substrate. Note that the surface of the second pattern is not subjected to sandblasting and has a surface roughness different from that of the first pattern. That is, the roughness of the metal surface of the second pattern is smaller than that of the first pattern. Therefore, the second pattern can efficiently reflect the light from the light emitting element in the emission observation direction. As described above, according to the forming method of the present invention, it is easy to form a wiring pattern in which the adhesion (first pattern) and the light reflectivity (second pattern) to the conductive member are functionally separated. Can be.

  The material of the conductive member to be the second pattern is preferably a metal selected from Au, Ag, Al, Cu, and Sn, or an alloy thereof, similarly to the material of the first pattern. Here, in consideration of adhesion between these metals and the ceramic substrate, the metal material may be laminated using a metal such as Ni or Pt as an underlayer.

  The conductor wiring in this step is formed by a method such as sputtering, vapor deposition, plating, or a combination of one or more of them. Moreover, the conductor wiring given by baking the resin binder in a conductor paste can also be made into a 2nd pattern.

(Semiconductor element)
The semiconductor element in the present invention may be a light emitting element, a light receiving element, a protective element (for example, a Zener diode or a capacitor) that protects the semiconductor element from destruction due to overvoltage, or a combination of two or more thereof. Here, a light emitting element (LED chip) will be described as an example of a semiconductor element. Examples of the semiconductor light-emitting element constituting the LED chip include those using various semiconductors such as ZnSe and GaN. However, in the case of a light-emitting device having a fluorescent material, the short-circuit that can efficiently excite the fluorescent material. wavelength capable of emitting nitride semiconductor _{(in X Al Y Ga 1-} X-Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) is preferably exemplified. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, and a pn junction, a heterostructure, and a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used.

  When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO or the like is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by MOCVD or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on the sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.

  As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer formed of n-type gallium nitride, a first clad layer formed of n-type aluminum nitride / gallium on a buffer layer, Examples include a double hetero structure in which an active layer formed of indium / gallium nitride, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. .

  Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, the p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant.

  The p-type semiconductor layer is provided with a diffusion electrode for spreading the current input to the light emitting element over the entire surface of the p-type semiconductor layer. Furthermore, a p-side pedestal electrode and an n-side pedestal electrode connected to a conductive member such as a bump or a conductive wire are provided on the diffusion electrode and the n-type semiconductor layer, respectively. Here, examples of the material of the bump include Au, Au—Sn eutectic, and lead-free solder. Moreover, as a material of an electroconductive wire, the fine wire which consists of Al, Au, Cu, or the alloy containing them is mentioned, for example.

  The diffusion electrode, the p-side pedestal electrode, and the n-side pedestal electrode are formed by an evaporation method or a sputtering method after exposing the n-type semiconductor by a method such as etching. Further, the shape of the diffusion electrode or the p-side pedestal electrode may be various shapes so that the current spreads uniformly over the entire surface of the light emitting element.

  In this embodiment, the material for the p-side and n-side pedestal electrodes preferably contains at least one of the materials contained in the bumps. That is, when the bump is made of Au, the material of the p-side and n-side pedestal electrode, particularly the uppermost layer material that becomes the bonding surface with the bump is Au or an alloy containing Au. For example, the p-side and n-side pedestal electrodes are made of W / Pt / Au or Rh / Pt / Au, and the thickness of each metal is several hundred to several thousand. In this specification, the symbol “A / B” indicates that the metal A and the metal B are sequentially laminated by a method such as sputtering or vapor deposition.

  The diffusion electrode formed on the entire surface of the p-type semiconductor layer is preferably made of a material that reflects light emitted from the light-emitting element toward the light-transmitting substrate of the light-emitting element. For example, Ag, Al, Rh, Rh / Ir can be mentioned. Furthermore, in combination with these materials, or alone, an oxide conductive film such as ITO (complex oxide of indium (In) and tin (Sn)), ZnO, Ni / Au, etc. on the entire surface of the p-type semiconductor. The metal thin film can be formed as a translucent electrode.

  Examples according to the present invention will be described in detail below. Needless to say, the present invention is not limited to the following examples.

  5 and 7 are a schematic perspective view and a cross-sectional view, respectively, of the light emitting device according to this example. The light emitting device according to this example includes a light emitting element, a ceramic substrate on which the light emitting element is mounted, and a lens that controls light distribution of the light emitting element. The light emitting element is flip-chip mounted on a conductor wiring of a ceramic substrate formed by sandblasting. The lens has a concave surface on the side facing the light emitting element and a uniform hemispherical shape in order to protect the light emitting element from the external environment and control the light distribution of the light from the light emitting element. .

  1 to 4 are schematic perspective views showing a process for forming a ceramic substrate according to this example. The formation process of the support member in the present embodiment will be described below with reference to the drawings.

(Process 1)
As shown in FIG. 1, sputtering using Au as a material is performed on a flat ceramic substrate 1 (size: 9.0 mm × 12 mm × 2.0 mm) made of aluminum nitride, and the first pattern 2 is formed. Form. The flat ceramic substrate 1 has a surface roughness (Ra) of 0.1 μm or less. By adopting such surface roughness, it is possible to obtain sufficient bonding strength when the light emitting element is flip-chip mounted with bumps in the light emitting element mounting step described later.

  The first pattern 2 includes regions 2a and 2c arranged in a strip shape facing each other at the corner of the front surface of the ceramic substrate, and a region 2b disposed near the center of the front surface of the ceramic substrate. Here, the regions 2a and 2c function as connection terminals for supplying power to the light emitting device from the outside. In addition, the region 2b is a region for forming a convex portion 4 (see FIG. 4) on which the light emitting element is placed by sandblasting and forming a conductor wiring connected to the light emitting element. The thickness of Au used as the first pattern is 0.1 μm to 1.0 μm on average. Thus, the first pattern can sufficiently function as a mask in the sputtering process, and can be fed with power by being well connected to the electrode of the light emitting element.

(Process 2)
FIG. 2 shows a ceramic substrate that is sandblasted by this process. Of the ceramic substrate, the portion of the ceramic substrate that is subjected to ceramic processing is shown as a shaded area. In this step, sandblasting is performed on the ceramic substrate exposed from the first pattern 2 using alumina particles having an average particle size of 7.0 μm to 30 μm as an abrasive. At this time, the abrasive is sprayed onto the surface of the ceramic substrate at a speed of 40 to 150 m / s. As a result, a recess having a depth of about 0.5 mm is formed in the ceramic substrate. Further, the exposed ceramic substrate has an inclination angle of the concave side wall of 70 degrees and a surface roughness (Ra) of 0.5 to 5.0 μm. By setting it as such surface roughness, the joint strength of the lens with respect to a ceramic substrate improves. Moreover, the sputtered second pattern 5 adheres to the ceramic substrate and does not peel off from the ceramic substrate.

  By the way, the surface of the 1st pattern 2 used as the mask of sandblasting is roughened by receiving the injection of an abrasive. In this way, the surface roughness can be imparted to the first pattern by appropriately adjusting the conditions for sandblasting. As a result, the wettability with the solder for electrical connection with the external electrode is improved, and a highly reliable semiconductor device can be obtained.

(Process 3)
As shown in FIG. 3, the second pattern 5 is applied to the ceramic ground surface that is cut and exposed by sandblasting. The second pattern 5 is also formed on the concave side wall surface (and the side surface of the convex portion) so as to be a continuous pattern from the region 2a to the region 2b and from the region 2c to the region 2b. Here, the continuous pattern from the region 2a to the region 2b and the continuous pattern from the region 2c to the region 2b are insulated from each other. As shown in FIG. 4, the second pattern 5 is electrically connected to the first pattern 2. Similarly to the first pattern 2, the second pattern 5 is formed by sputtering using Au as a material, and the thickness of the Au is 0.1 μm to 1.0 μm on average. Through the above steps, a ceramic substrate to be a support member of the light emitting element is formed.

(Light emitting element)
The light emitting element in this example uses a nitride semiconductor element having an In _0.2 Ga _0.8 N semiconductor of 460 nm whose monochromatic emission peak is visible light as an active layer. More specifically, the LED chip as a light emitting element is nitrided by MOCVD by flowing TMG (trimethylgallium) gas, TMI (trimethylindium) gas, nitrogen gas and dopant gas together with a carrier gas onto a cleaned sapphire substrate. It can be formed by depositing a physical semiconductor. A layer to be an n-type nitride semiconductor or a p-type nitride semiconductor is formed by switching between SiH ₄ and Cp ₂ Mg as the dopant gas.

  The element structure of the LED chip of this example is an n-type contact layer in which a GaN layer that is an undoped nitride semiconductor and an Si-doped n-type electrode are formed on a sapphire substrate that is a translucent substrate. Laminate a GaN layer and a GaN layer that is an undoped nitride semiconductor, and further laminate a GaN layer that becomes a barrier layer and an InGaN layer that becomes a well layer as a set, and finally a GaN layer that becomes a barrier layer. Thus, an active layer is formed, and the active layer has a multiple quantum well structure. Furthermore, an AlGaN layer as a p-type cladding layer doped with Mg and a p-type GaN layer as a p-type contact layer doped with Mg are sequentially stacked on the active layer. A GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.

  Etching exposes the surfaces of the p-type contact layer and the n-type contact layer on the same side of the nitride semiconductor on the sapphire substrate. Next, sputtering using ITO (indium and tin composite oxide) and Rh as materials is sequentially performed on the p-type contact layer, and a diffusion electrode is provided on almost the entire surface of the p-type contact layer exposed in a stripe shape. By setting it as such an electrode, the electric current which flows through a diffused electrode can be spread over the wide range of a p-type contact layer, the luminous efficiency of a LED chip can be improved, and it can be made to light-emit uniformly.

  Further, sputtering using W, Pt, and Au as materials is sequentially performed, and the diffusion electrode and a part of the n-type contact layer are stacked to form a p-side pedestal electrode and an n-side pedestal electrode. Finally, a chip is formed by dicing to obtain a semiconductor light emitting element chip of □ = 1 mm × 1 mm.

  In the light emitting device of this embodiment, the n-type pedestal electrodes are formed at both corners of the n-type semiconductor exposed in a stripe shape, that is, at both corners of the light emitting device chip. In addition, the n-type semiconductor exposed by etching has a constricted portion that narrows from the position of the corner where the n-type base electrode is formed toward the center of the light-emitting element when viewed from the upper surface direction of the light-emitting element. Moreover, it has an extending | stretching part so that a pair of constricted part which mutually opposes may be tied. Further, a p-side semiconductor layer, a diffusion electrode, or a p-side pedestal electrode is formed at a position sandwiching the extended portion.

(Mounting of light emitting elements)
As shown in FIG. 3 or FIG. 4, a convex portion 4 is formed almost at the center of the front surface of the ceramic substrate that has been sandblasted. As shown in FIG. 6, in this embodiment, four light emitting element chips are arranged in a line and flip-chip mounted with the upper surface of the convex portion 4 as a mounting surface.

  On the upper surface of the convex portion 4, a conductor wiring made of Au formed simultaneously with the formation of the first pattern 2 is applied. The conductor wiring is a pair of positive and negative conductor wirings facing the p-side pedestal electrode and the n-side pedestal electrode of the light emitting element via the bumps. In the light emitting element, the p-side and n-side pedestal electrodes are opposed to the conductor wiring through Au bumps. Further, by applying a load, ultrasonic waves and heat, the bumps are welded, and the light emitting element is bonded to the conductor wiring.

  It is preferable that the gap generated between the light emitting element chip and the mounting surface is filled with an epoxy resin or a silicone resin as an underfill. Thereby, the deterioration of the quality by the said gap can be prevented. That is, if bubbles exist between the light emitting element chip and its mounting surface, the bubbles may expand when the light emitting element chip generates heat, leading to poor electrical connection between the light emitting element and the conductor wiring. Therefore, generation of bubbles can be prevented, and a highly reliable light-emitting device can be obtained.

(Formation of light conversion member)
The light emitting element is covered with a light conversion member containing a fluorescent material. As a result, the light emitting device in this embodiment can emit mixed color light of light from the light emitting element and light from the fluorescent material that is excited by the light and emits light.

The fluorescent material in this example is a coprecipitated oxide obtained by coprecipitation of oxalic acid with a solution obtained by dissolving a rare earth element of Y, Gd, and Ce in an acid in a stoichiometric ratio with oxalic acid, and aluminum oxide. To obtain a mixed raw material. Further, barium fluoride is mixed as a flux, then packed in a crucible, and fired in air at a temperature of 1400 ° C. for 3 hours to obtain a fired product. The fired product is ball _milled in water, washed, separated, dried, and finally passed through a sieve to have a center particle size of 8 μm (Y _0.995 Gd _0.005 ) _2.750 Al ₅ O ₁₂ : Ce _0.250 phosphor Form. As a material for the light conversion member, 20 to 75 wt% of the above-mentioned fluorescent substance is contained in a silicone resin, and the mixture is stirred for 5 minutes by a rotation and revolution mixer to obtain a mixture of a phosphor and a silicone resin as a binder. Further, the mixture is screen-printed and cured on the sapphire substrate surface, which is the light emission observation side main surface of the semiconductor light-emitting element mounted on the flip chip, thereby forming a light conversion member.

(Lens mounting)
As shown in FIGS. 5 and 7, the lens 6 that is an optical member in the present embodiment is convex on the light emission observation side of the light emitting device, and has a spherical surface having a hemispherical cavity on the mounting side facing the ceramic substrate. 6a and a flange portion 6b which becomes an outer edge of the spherical surface portion 6a and is fixed to the support substrate. The flange 6b is fitted into a concavo-convex shape formed on the front surface of the ceramic substrate. That is, a part of the end portion of the flange portion 6b is opposed to the recess side wall surface of the ceramic substrate, and a part of the other end portion is aligned in the side surface direction of the ceramic substrate.

  The lens 6 in this embodiment is mounted in a nitrogen gas atmosphere, and is fixed using a ceramic substrate and an epoxy resin as an adhesive. The light emitting element 7 is hermetically sealed by the lens 6 and the ceramic substrate 1.

  The material of the lens 6 is soft glass (borosilicate glass), and the thickness of the flange portion 6b of the lens is 0.5 mm which is substantially equal to the depth of the ceramic substrate subjected to sandblasting (depth of the recess). Therefore, the upper surface of the flange portion 6b is substantially flush with the upper surface of the concave side wall 3a of the ceramic substrate 1, and is almost flush with the upper surface of the convex portion 4 that is the mounting surface of the light emitting element. Thereby, since the light from the light emitting element mounted on the upper surface of the convex portion is incident on the spherical surface portion of the lens without being blocked by the collar portion or the adhesive, the light emitting device having excellent optical characteristics can be obtained. .

  In the step 3, it is preferable that the second pattern arrangement is such that the sandblasted ceramic substrate is exposed, and the ceramic substrate is used as an adhesive surface. Thereby, compared with the case where the 2nd pattern which consists of metal materials is used as an adhesive surface, the adhesive strength of an optical member can be improved.

  As described above, the semiconductor device according to this example can be obtained with high mass productivity as a light emitting device having excellent heat dissipation.

  The support substrate and the semiconductor device according to the present invention can be used for home lighting or in-vehicle lighting as a light-emitting device in which a relatively large amount of power is input and a high-power light-emitting element is housed.

FIG. 1 is a perspective view schematically showing a method for forming a light emitting device according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing a method for forming a light emitting device according to an embodiment of the present invention. FIG. 3 is a perspective view schematically showing a method for forming a light emitting device according to an embodiment of the present invention. FIG. 4 is a perspective view schematically showing a method for forming a light emitting device according to an embodiment of the present invention. FIG. 5 is a schematic perspective view of a light emitting device according to an embodiment of the present invention. FIG. 6 is a perspective view schematically showing a method for forming a light emitting device according to an embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate 2, 2a, 2b, 2c ... 1st pattern 3a, 3b ... Side wall 4 ... Convex part 5 ... 2nd pattern 6 ... Lens 6a ... Spherical surface portion 6b ... collar portion 7 ... semiconductor light emitting element 8 ... light emitting device

Claims (12)

A method for forming a support substrate on which a semiconductor element having a pair of positive and negative electrodes on the same surface side is mounted,
A first step of forming a first pattern with a conductive member on a region of the surface of the ceramic substrate facing the pair of positive and negative electrodes of the semiconductor element ;
A second step of forming a concave portion of the roughened ceramic body by subjecting the surface on which the first pattern is formed to sandblasting using the first pattern as a mask ;
And a third step of forming a second pattern with a conductive member in the recess so as to be electrically connected to the first pattern . The method for forming a support substrate according to claim 1 , which is sandblasted with an abrasive having an average particle size of 7 to 30 μm. A method of forming a semiconductor device having a semiconductor element having a pair of positive and negative electrodes on the same surface side and a support substrate on which the semiconductor element is mounted,
A first step of forming a first pattern with a conductive member in a first region facing the pair of positive and negative electrodes of the semiconductor element on the surface of the ceramic substrate;
A second step of forming a concave portion of the roughened ceramic body by subjecting the surface on which the first pattern is formed to sandblasting using the first pattern as a mask ;
A third step of forming a second pattern with a conductive member so as to be electrically connected to the first pattern in the recess ;
A method for forming a semiconductor device, comprising: a fourth step of electrically connecting the semiconductor element and the first pattern . The said 1st pattern WHEREIN: Said 1st pattern is formed in said 1st area | region in the surface of the said ceramic substrate, and the 2nd area | region which supplies electric power to this semiconductor device. A method for forming a semiconductor device. In the first step, the second region is formed opposite to each other at the corner of the ceramic substrate,
In the second step, a convex part having the second region on the upper surface is formed by the concave part,
5. The method of forming a semiconductor device according to claim 4, further comprising a fifth step of fitting and fixing an end portion of the flange portion of the optical member having a flange portion on an outer edge to the side wall surface of the convex portion . The convex part which has said 1st field on the upper surface is formed in said 2nd process by said 2nd process, and this convex part upper surface is substantially flush with the collar upper surface of said optical member. Method for forming the semiconductor device. 7. The method of forming a semiconductor device according to claim 5, wherein the second pattern is formed so that the ceramic base of the concave portion is exposed, and the optical member is bonded to the ceramic base. In the second step, the concave portion forms a convex portion having the first region on the upper surface, and the side surface of the convex portion gradually extends in a direction opposite to the semiconductor element from the mounting surface of the semiconductor element. The method for forming a semiconductor device according to claim 3, wherein the semiconductor device has a tapered shape with a large cross-sectional area. A semiconductor device having a semiconductor element having a pair of positive and negative electrodes on the same surface side , and a support substrate having a conductor wiring electrically connected to the semiconductor element and mounting the semiconductor element,
The support substrate is a ceramic substrate,
The conductor wiring, and the first conductor wiring region having a first region are electrically connected via the electrode and the conductive member of the semiconductor element,
Have a said first region and electrically second conductor wiring region for connecting,
The second conductor wiring region is formed in a concave portion of a roughened ceramic body formed by subjecting the support substrate to sandblasting using the first conductor wiring region as a mask. A semiconductor device. The semiconductor device according to claim 9, wherein the surface roughness of the second conductor wiring region is smaller than the surface roughness of the first conductor wiring region. The first conductor wiring region has a second region for supplying power to the semiconductor device,
The semiconductor device according to claim 9, wherein the second conductor wiring region electrically connects the first region and the second region. The semiconductor device has an optical member having a flange on an outer edge,
The second region is formed opposite to each other at the corner of the support substrate,
The semiconductor device according to claim 11 , wherein a convex portion having the second region on an upper surface is provided by the concave portion, and an end portion of the flange portion of the optical member is fitted to a side wall surface of the convex portion .

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