JP2016111364A - Light-emitting device and apparatus having the light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which has a high heat dissipation, and an excellent reliability of an electric connection of a semiconductor chip and a connection substrate.SOLUTION: A light-emitting device comprises: an aluminum nitride substrate 11; a semiconductor chip 10 that has a semiconductor laminate part 13 formed to a first principal surface 11a side of the aluminum nitride substrate 11 and a first electrode part 15 formed to the first principal surface 11a side of the aluminum nitride substrate 11 and electrically connected to the semiconductor laminate part 13; and a connection substrate 30 that has a second electrode part 33 formed to a first principal surface 31a side of a ceramic substrate 31. In a state where the first principal surface 11a of aluminum nitride substrate 11 faces to the first principal surface 31a of ceramic substrate 31, and the first electrode part 15 and the second electrode part 33 are connected each other, a gap is arranged between the semiconductor laminate part 13 and the first principal surface 31a of ceramic substrate 31 so as to have a distance of 10 μm or less therein, and an underfill 50 including a resin and a filler of which an average particle size is equal to 1 μm or less is filled to the gap.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device and a device including the light emitting device.

  A semiconductor device based on a nitride substrate is expected to be applied to a light emitting device that emits light, a light receiving device that receives light, and a power device by taking advantage of its wide band gap. In particular, a semiconductor light emitting device having an aluminum nitride (AlN) substrate can emit deep ultraviolet light having a wavelength of 280 nm or less, and can be used for sterilization applications. : UltraViolet C-Light Emitting Diode) is expected to be developed.

  In addition, as a prior art regarding a light-emitting device, there exist some which were disclosed by patent documents 1-3, for example.

JP 2005-277423 A JP 2006-93632 A JP 2004-172160 A

By the way, the UVC-LED easily generates heat, and depending on the method of use, the element temperature may rise to nearly 100 ° C. due to heat generation. Further, when the semiconductor chip constituting the LED is mounted on the connection substrate or the like by the flip chip method, the junction between the semiconductor chip and the connection substrate (for example, the first electrode portion included in the semiconductor chip, There is a possibility that stress is applied to the second electrode portion of the connection substrate) and the joint portion is broken to cause an electrical failure (for example, an open failure or a short failure).
Therefore, the present invention has been made in view of such circumstances, a light emitting device having high heat dissipation and excellent electrical connection reliability between a semiconductor chip and a connection substrate, and an apparatus including the light emitting device The purpose is to provide.

In order to solve the above problems, a light-emitting device according to one embodiment of the present invention is formed on a substrate, a semiconductor stacked portion formed on a first main surface side of the substrate, and a first main surface side of the substrate. A semiconductor chip having a first electrode portion electrically connected to the semiconductor laminated portion, and a connection substrate having a second electrode portion formed on the first main surface side of the base material, In a state where the first main surface and the first main surface of the connection substrate are opposed to each other and the first electrode portion and the second electrode portion are in contact with each other, A gap having a distance of 10 μm or less is provided, and the gap is filled with a filler containing a resin and a filler having an average particle diameter of 1 μm or less.
An apparatus according to one embodiment of the present invention includes the above light-emitting device.

  According to one embodiment of the present invention, a light-emitting device that has high heat dissipation and excellent electrical connection reliability between a semiconductor chip and a connection substrate, and a device including the light-emitting device can be provided.

It is sectional drawing which shows the structural example of the light-emitting device main body 100 which concerns on this embodiment. FIG. 4 is a cross-sectional view illustrating a configuration example of a semiconductor stacked unit 13. 3 is a cross-sectional view illustrating a configuration example of a light emitting device 200. FIG. It is a conceptual diagram which shows the mounting process of this embodiment. It is sectional drawing which shows the structural example of 100 A of light-emitting device main bodies which concern on the modification of this embodiment. 3 is an SEM image obtained by photographing a part of the light emitting device of Example 1. FIG.

Hereinafter, modes for carrying out the present invention will be described.
<Light emitting device>
[overall structure]
A light emitting device according to an embodiment for carrying out the present invention (hereinafter referred to as “this embodiment”) includes a semiconductor chip and a connection substrate. The semiconductor chip includes a substrate, a semiconductor stacked portion formed on the first main surface of the substrate, and a first electrode portion formed on the semiconductor stacked portion. The semiconductor stacked portion includes a light emitting layer. Further, the connection substrate has a base material and a second electrode portion formed on the first main surface side of the base material. In this light emitting device, the first main surface of the substrate and the first main surface of the connection substrate face each other, and the first electrode portion and the second electrode portion are in contact with each other, between the semiconductor chip and the connection substrate. , A gap having a distance of 10 μm or less (that is, a separation distance) is provided. The gap is filled with a filler. The filler includes a resin and a filler having an average particle diameter of 1 μm or less.

In the present embodiment, the substrate may be an aluminum nitride (AlN) substrate. The substrate may be a sapphire (Al ₂ O ₃ ) substrate. The connection substrate is a substrate separate from the substrate included in the semiconductor chip and is also referred to as a submount. The connection substrate may be a ceramic substrate with high heat dissipation. Examples of the ceramic substrate include an alumina substrate and an aluminum nitride substrate. The second electrode part may have a bump. The main component of the filler may be silica. Here, a main component means a component with a high ratio in the whole filler. The proportion of silica in the entire filler is, for example, 50% by mass or more and 100% by mass or less.

In the present embodiment, the filler resin may be an epoxy resin having a glass transition temperature of 100 ° C. or higher.
In the present embodiment, the substrate may include a first portion including the first main surface of the substrate and a second portion including the second main surface opposite to the first main surface of the substrate. Good. When the substrate is viewed in cross section (or side view), the distance between both side surfaces of the first part is shorter than the distance between both side surfaces of the second part, and the thickness of the second part is 2 μm or more and 100 μm or less. There may be.

  In the present embodiment, the semiconductor stacked portion may emit ultraviolet light having a wavelength of 240 nm or more and 320 nm or less when a preset voltage is applied. That is, the light emitting device according to the present embodiment may be an ultraviolet light emitting device that emits ultraviolet light having a wavelength of 240 nm or more and 320 nm or less. An ultraviolet light emitting device that emits ultraviolet light having a wavelength of 240 nm or more and 320 nm or less can be applied to various applications such as sterilization and separation of protein components. Hereinafter, the light-emitting device according to the present embodiment will be described more specifically with reference to the drawings.

[Concrete example]
(1) Light Emitting Device Main Body FIG. 1 is a cross-sectional view illustrating a configuration example of a light emitting device main body 100 according to the present embodiment. The light emitting device main body 100 is an ultraviolet light emitting device that emits ultraviolet light having a wavelength of 240 nm or more and 320 nm or less, for example.

  As shown in FIG. 1, the light emitting device main body 100 includes a semiconductor chip 10 and a connection substrate 30. The semiconductor chip 10 includes an aluminum nitride substrate 11, a semiconductor stacked portion 13 formed on a first main surface (for example, surface) 11 a of the aluminum nitride substrate 11, and a first electrode portion formed on the semiconductor stacked portion 13. 15 and. The connection substrate 30 includes a second electrode portion 33 formed on a first main surface (for example, a surface) 31 a of the ceramic substrate 31 using the ceramic substrate 31 as a base material.

  In the light emitting device main body 100, the first main surface 11a of the aluminum nitride substrate 11 and the first main surface 31a of the ceramic substrate 31 face each other, and the first electrode portion 15 and the second electrode portion 33 are in contact with each other. A gap having a distance L1 of 10 μm or less is provided between the semiconductor laminate 13 and the first major surface 31a of the ceramic substrate 31. The gap is filled with an underfill 50 containing a resin and a filler having an average particle diameter of 1 μm or less as a filler.

(2) Aluminum nitride substrate The aluminum nitride substrate 11 is, for example, a substrate made of a single crystal (that is, an aluminum nitride single crystal substrate). Although the manufacturing method of the aluminum nitride substrate 11 is not particularly limited, it is preferably manufactured by a sublimation method using aluminum nitride ceramics as a raw material from the viewpoint of obtaining a high-quality aluminum nitride single crystal substrate. The dislocation density of the aluminum nitride substrate 11 is preferably less than 10 ⁷ cm ⁻² , particularly preferably less than 10 ⁵ cm ⁻² .

The incomplete surface treatment for the aluminum nitride substrate 11 increases the dislocation density of the semiconductor stacked portion 13 (the first semiconductor layer 21 shown in FIG. 2 described later) formed thereon. In order to prevent this, the RMS surface roughness of the first main surface 11a of the aluminum nitride substrate 11 is preferably less than about 0.5 nm with respect to an area of length × width = 10 μm × 10 μm.
The aluminum nitride substrate 11 includes a first portion 111 including the first main surface 11a and a second portion 112 including the second main surface (for example, the back surface) 11b opposite to the first main surface 11a. Have. When the aluminum nitride substrate 11 is viewed in cross section (or in a side view), the distance L11 between both side surfaces of the first portion 111 is shorter than the distance L12 between both side surfaces of the second portion 112. The thickness T12 of the second portion 112 is 2 μm or more and 100 μm or less.

(2.1) Semiconductor Stacking Section FIG. 2 is a cross-sectional view showing a configuration example of the semiconductor stacking section 13.
As shown in FIG. 2, the semiconductor stacked portion 13 is formed on the first conductive type first semiconductor layer 21 formed on the first main surface 11 a of the aluminum nitride substrate 11 and on the first semiconductor layer 21. The light emitting layer 22 and a second conductivity type second semiconductor layer 23 formed on the light emitting layer 22. The first conductivity type is one of p-type and n-type, and the second conductivity type is the other of p-type and n-type.
Although not shown, a buffer layer may be provided between the aluminum nitride substrate 11 and the semiconductor laminated portion 13. The buffer layer is composed of, for example, an aluminum nitride layer formed by homoepitaxial growth on the aluminum nitride substrate 11.

(2.1.1) First Semiconductor Layer The first semiconductor layer 21 is made of, for example, indium aluminum gallium nitride (InAlGaN) doped with impurities or aluminum gallium nitride (AlGaN) doped with impurities. Yes. Examples of the impurity include magnesium (Mg) as a p-type impurity and silicon (Si) as an n-type impurity.

For example, the first semiconductor layer 21 has a plurality of layers made of In _x AlyGa _1-xy N (0 ≦ x + y ≦ 1), and at least a part of the plurality of layers is a lattice of the light emitting layer 22. It is distorted in a pseudo-lattice matching to approach the parameters. Alternatively, the first semiconductor layer 21 includes one or a plurality of layers of In _x AlyGa _1-xy N (0 ≦ x + y ≦ 1), and xy in the composition formula changes with the thickness (that is, along the thickness direction). Or a composition that changes linearly or stepwise).

  A portion of the first semiconductor layer 21 including the interface with the aluminum nitride substrate 11 preferably has almost the same composition as the aluminum nitride substrate 11. Thereby, the two-dimensional growth of the first semiconductor layer 21 is promoted, and inconvenient island formation can be avoided. Further, by avoiding such island formation, it is possible to avoid an undesirable elastic strain relaxation in the first semiconductor layer 21 and the subsequent growth layer.

(2.1.2) Light-Emitting Layer The light-emitting layer 22 includes, for example, a multiple quantum well (“MQW”) layer. The MQW layer includes a plurality of quantum wells, and each quantum well is made of, for example, InAlGaN or AlGaN.
For example, the MQW layer includes an Al _x Ga _1-x N quantum well and an Al _y Ga _1-y N quantum well, one of which is stacked on the other. Here, _x of the Al _x Ga _1-x N quantum well and _{y of} the Al _y Ga _1-y N quantum well are different from each other. The difference between x and y is preferably large enough to obtain good confinement of electrons and holes in the active region. This can increase the ratio of radioactive recombination to non-radioactive recombination.

In the MQW layer including the Al _x Ga _1-x N quantum well and the Al _y Ga _1-y N quantum well, when the values of x and y are exemplified, the difference between x and y is about 0.05, and x is About 0.35 and y is about 0.4. If the difference between x and y is excessively large (for example, greater than about 0.3), inconvenient island formation occurs during the formation of the MQW layer. For this reason, the difference between x and y is preferably 0.3 or less, for example.

In addition, the MQW layer may include a plurality of periods with a pair of Al _x Ga _1-x N quantum wells and Al _y Ga _1-y N quantum wells as one period, and the total thickness (ie, total thickness) is about It may be less than 50 nm.
The light emitting layer 22 may also have an optional thin electron block (or hole block if n-type contact is placed on top of the device) layer. The electron blocking layer may be made of Al _x Ga _1-x N doped with one or more impurities such as Mg, for example. The thickness of the electron block layer is, for example, about 20 nm.

(2.1.3) Second Semiconductor Layer The second semiconductor layer 23 formed on the light emitting layer 22 is made of, for example, InAlGaN doped with impurities or AlGaN doped with impurities. Examples of the impurity include magnesium (Mg) as a p-type impurity and silicon (Si) as an n-type impurity.

The second semiconductor layer 23 is doped n-type or p-type, but has conductivity opposite to that of the first semiconductor layer 21. For example, when the first semiconductor layer 21 is doped with an n-type impurity such as Si and exhibits n-type conductivity, the second semiconductor layer 23 is doped with a p-type impurity such as Mg and has p-type conductivity. Is shown. The thickness of the second semiconductor layer 23 is, for example, about 50 nm to about 100 nm.
The second semiconductor layer 23 may have a cap layer containing a semiconductor material doped to the second conductivity type. When the second semiconductor layer 23 exhibits p-type conductivity, the cap layer includes, for example, Mg doped GaN, and has a thickness of about 10 nm to about 100 nm, preferably about 50 nm.

(2.1.4) Number and Shape of Semiconductor Laminate Portions FIG. 1 shows only one semiconductor laminate portion 13 included in the semiconductor chip 10. However, in the present embodiment, the semiconductor chip 10 may have one or more semiconductor stacked portions 13. From the viewpoint of improving the light emission amount per unit area, the semiconductor chip 10 may preferably include a plurality of semiconductor stacked portions 13 connected in parallel. Further, the shape of the semiconductor stacked portion 13 is not particularly limited, and may be, for example, a rectangular shape, a circular shape or an elliptical shape, a polygonal shape, or a shape obtained by combining them in a plan view.

(2.2) First Electrode Part The first electrode part 15 shown in FIG. 1 is an electrode part for supplying power to the light emitting layer of the semiconductor stacked part 13. In the present embodiment, the shape and arrangement of the first electrode portion 15 are not particularly limited, but when the semiconductor stacked portion 13 has a mesa structure, an example in which one end of the electrode portion is arranged on each of the mesa top portion and the mesa bottom portion is given. It is done. In addition, there is an example in which one end of the electrode portion is disposed on each of the upper and lower surfaces of the element.

  In FIG. 1, one of the two first electrode portions 15 is electrically connected to the second semiconductor layer 23 (see FIG. 2) at the top of the mesa, and the other of the two first electrode portions 15 is It is electrically connected to the first semiconductor layer 21 (see FIG. 2) at the bottom of the mesa. The semiconductor stacked portion 13 is partially covered with an insulating layer (not shown). By this insulating layer (not shown), one of the first electrode portions 15 (that is, the electrode portion electrically connected to the second semiconductor layer 23 at the top of the mesa) is electrically connected from the light emitting layer 22 and the first semiconductor layer 21 at the bottom of the mesa. Is insulated.

  The first electrode portion 15 is made of a conductive material, and is made of, for example, gold (Au), nickel (Ni), aluminum (Al), titanium (Ti), or a combination thereof. For example, the first electrode portion 15 connected to the p-type semiconductor layer is made of a Ni / Au alloy, and the first electrode portion 15 connected to the n-type semiconductor layer is Ti / Al / Ti / Au. It consists of a stack. The first electrode unit 15 is formed by sputtering or vapor deposition, for example.

  The first electrode portion 15 may also include a function as an ultraviolet (“UV”) reflector. The UV reflector redirects photons emitted toward the first electrode portion 15 (that is, prevents photons from escaping from the semiconductor stack 13) and a desired light emitting surface (eg, bottom surface). It is designed to improve the extraction efficiency of photons generated in the active region of the device by redirecting the photons towards the.

(3) Light Emitting Device FIG. 3 is a cross-sectional view illustrating a configuration example of the light emitting device 200. As shown in FIG. 3, the light emitting device 200 includes a light emitting device main body 100 and a package 150 that houses the light emitting device main body 100.
(3.1) Package As shown in FIG. 3, the package 150 that houses the light emitting device main body 100 is, for example, a TO-39 can package. The package 150 includes a pedestal 160, a cap 170 disposed on the upper surface 160 a side of the pedestal 160, and an external connection terminal 180 provided on the lower surface 160 b side of the pedestal 160. The cap 170 has a quartz lens 175 provided on the top thereof. The light emitting device main body 100 is attached to the upper surface 160 a side of the pedestal 160 and is covered with a cap 170. For example, the 2nd main surface (for example, back surface) 31b on the opposite side to the 1st main surface 31a of the ceramic substrate 31 is joined to the upper surface 160a of the base 160 via the silver paste. In this state, the quartz lens 175 and the second main surface 11a of the aluminum nitride substrate 11 face each other.

<Method for manufacturing light emitting device>
[overall structure]
The method for manufacturing a light emitting device according to this embodiment includes a step of forming the semiconductor stacked portion and the first electrode portion on the first main surface of the substrate (previous step), and a second main surface facing the first main surface of the substrate. CMP process is performed on the surface to process the arithmetic average roughness Ra of the second main surface to 20 nm or less (processing step), the substrate is irradiated with laser light from the second main surface side, and a plurality of substrates are formed. And a step of dividing into individual semiconductor chips (individualization step). In the present embodiment, the processing step and the individualization step are collectively referred to as a post step.

  In addition, the method for manufacturing the light emitting device according to the present embodiment includes a step (mounting step) of mounting the above-described individual semiconductor chip on the connection substrate after the post step. In this mounting process, the semiconductor chip is electrically connected to the connection substrate by a flip chip method. That is, the first main surface having the first electrode portion of the substrate is opposed to the first main surface having the second electrode portion of the connection substrate, and the first electrode portion and the second electrode portion are electrically connected. To do.

Furthermore, the method for manufacturing a light emitting device according to the present embodiment includes a step of storing a device (that is, a light emitting device main body) including a semiconductor chip and a connection substrate in a package (package storing step) after the mounting step. .
As shown in FIG. 3, the package for housing the light emitting device main body is, for example, a TO-39 can package. In the package storing step, for example, the second main surface of the connection substrate is bonded to the upper surface of the pedestal of the can package via a silver paste. After this joining, a cap with a quartz lens is welded to the pedestal to complete the light emitting device. Next, the method for manufacturing the light emitting device according to this embodiment will be described more specifically.

[Concrete example]
(1) Pre-process First, as shown in FIG. 1, for example, an aluminum nitride substrate 11 is prepared as a substrate. This aluminum nitride substrate 11 is a wafer until the individualization step is performed. Next, a semiconductor thin film is formed on the first main surface 11 a of the aluminum nitride substrate 11. As shown in FIG. 2, the semiconductor thin film is a semiconductor thin film having a laminated structure including a first conductive type first semiconductor layer 21, a light emitting layer 22, and a second conductive type second semiconductor layer 23.

  When the light emitting device according to this embodiment is a deep ultraviolet light emitting device, the structure of the semiconductor thin film is a structure capable of emitting deep ultraviolet light, and the composition of the semiconductor thin film is a nitride semiconductor that matches the wavelength of the desired deep ultraviolet light. Of the composition. The light emitting layer 22 may have a quantum well structure. A buffer layer may be provided between the aluminum nitride substrate 11 and the semiconductor thin film. This buffer layer is a layer for relaxing lattice mismatch. The semiconductor thin film can be formed by, for example, a metal organic chemical vapor deposition (MOCVD) method.

  Next, the semiconductor thin film is patterned to form a mesa-structured semiconductor stacked portion 13 on the first main surface 11a of the aluminum nitride substrate 11, as shown in FIG. The patterning of the semiconductor thin film can be performed by, for example, photolithography and dry etching techniques. Thereafter, the first electrode portion 15 that is electrically connected to the semiconductor stacked portion 13 having the mesa structure is formed. The first electrode unit 15 is formed using, for example, sputtering or vapor deposition and a lift-off technique.

(2) Post-process In the aluminum nitride substrate 11 in which the semiconductor laminated portion 13 and the first electrode portion 15 are formed on the first main surface 11a, the opposing second main surface 11b is ground by a mechanical and chemical technique. Thereby, the thickness of the aluminum nitride substrate 11 is thinly processed to half or less of the thickness before grinding (that is, the original thickness). For example, when thinning from the original thickness by 100 μm or more, it is mechanically ground. Since the aluminum nitride substrate 11 has a height equivalent to that of diamond, the aluminum nitride substrate 11 is cut with fine abrasive diamond. However, in the case of mechanical grinding, scratches on the submicron (μm) order remain on the surface to be ground (that is, the second main surface 11b). Therefore, when such scratches remain on the second main surface 11b, the scratches may be removed by polishing the second main surface 11b by a mechanical chemical polishing (CMP) method.

  Further, in order to make an element, it is important to separate the aluminum nitride substrate 11 into pieces. A semiconductor element such as an ordinary LSI is processed by blade dicing, but the aluminum nitride substrate 11 has high hardness, and processing by blade dicing is difficult. Therefore, the aluminum nitride substrate 11 is irradiated with laser light to form a groove, and then the aluminum nitride substrate 11 is mechanically divided along the groove to separate the aluminum nitride substrate 11. . The type of laser beam used for this processing is not particularly limited, but a high-density laser beam is desirable to reduce the thermal load on the aluminum nitride substrate 11, and for example, a laser beam with a wavelength of 365 nm or a laser beam with a wavelength of 265 nm Is desirable. The dicing using the laser beam may be performed by a stealth dicing method.

In the present embodiment, after laser scribing is performed on the aluminum nitride substrate 11, the cutting edge is applied to the first main surface 11a facing the scribe surface (second main surface 11b), and the aluminum nitride substrate 11 is used as an element pattern. Divide along.
By this separation, as shown in FIG. 1, the first portion 111 and the second portion 112 of the aluminum nitride substrate 11 are formed.

(3) Mounting Process FIG. 4 is a conceptual diagram showing the mounting process of this embodiment. As shown in FIG. 4, in the mounting process of this embodiment, the separated semiconductor chip 10 is mounted on a connection substrate 30 called a submount by a flip chip method. In the electrical connection by the flip chip method, appropriate heat, ultrasonic waves, and weights are applied to the first electrode portion 15 of the semiconductor chip 10 and the second electrode portion 33 of the connection substrate 30, so that the first electrode portion 15 and the second electrode portion 15 The electrode part 33 is joined. The second electrode portion 33 of the connection substrate 30 is preferably made of a material that has high heat dissipation and can be satisfactorily bonded to the semiconductor chip 10. Examples of such a material include gold, silver, copper, and gold tin. Moreover, the 2nd electrode part 33 may have a bump part which consists of any one of these each materials, or those combination.

  In general, gold tin solder is used as the electrode portion of the connection substrate. However, in the case of gold tin, since solder is used, it cannot be formed thin, and the thickness of the electrode portion after bonding is about 30 μm. Is the limit. Furthermore, since the electrode parts are joined by being melted by heating, in a semiconductor chip in which the interval between the adjacent electrode parts is narrow, the electrode parts may be electrically short-circuited, which is not preferable.

  Therefore, in this embodiment, it is preferable to form gold, silver, copper, or the like on the second electrode portion 33 of the connection substrate 30 by plating. Among these, in order to join by the flip chip method, the material of the second electrode portion 33 is preferably gold or silver having a soft property and low electrical resistance. In the present embodiment, an element obtained by bonding the semiconductor chip 10 and the connection substrate 30 by a flip chip method is also referred to as a CoS (Chip on Submount) element.

Thereafter, an underfill is injected between the semiconductor chip 10 of the CoS element and the connection substrate 30. For example, while the underfill filled in the syringe is heated, the nozzle tip of the dispenser is disposed on the side surface of the semiconductor chip 10, and the underfill is filled between the semiconductor chip 10 and the connection substrate 30 using surface tension.
For the underfill, it is important to select a filler for adjusting the fluidity and the linear expansion coefficient. Normally, the gap (gap) filled with underfill is about 30 μm, but in this embodiment, the distance L1 of the gap between the semiconductor chip 10 and the connection substrate 30 is as very small as 10 μm or less.

Here, when the underfill filler diameter is larger than the gap, filling of the underfill is hindered. Therefore, the underfill filler diameter is preferably smaller than this gap. In this embodiment, since the distance L1 of the gap between the semiconductor chip 10 and the connection substrate 30 is 10 μm or less, the filler diameter is preferably 10 μm or less.
Further, since the bumps are crushed at the time of joining by the flip chip method, it is necessary to consider the amount of crushed bumps at the time of joining. When the inventor performed the flip chip bonding, the bumps were crushed to a maximum height of 3 μm. For this reason, in this embodiment, it is preferable to use an underfill that is guaranteed to have a filler diameter of 3 μm or less.

  The light emitting device main body 100 generates heat when energized. For this reason, when the glass transition temperature of the resin contained in the underfill is low, the resin of the underfill expands when energized, and this bonding is separated from the bonding portion between the electrode portion of the semiconductor chip and the electrode portion of the connection substrate. There is a possibility that a force is applied in the direction, and the joint portion is broken and electrically short-circuited. Considering this point, in the present embodiment, it is preferable that the glass transition temperature of the resin contained in the underfill is lower than the temperature when the light emitting device is energized. Moreover, as such a resin, an epoxy resin having a high glass transition temperature is preferable. In the present embodiment, for example, the light emitting device main body 100 may be formed using an underfill whose main component is an epoxy resin having a glass transition temperature of about 125 ° C.

(4) Package storing step In the package storing step, the CoS element (that is, the light emitting device main body 100) after filling the gap with the underfill is stored in the package 150. For example, as package 150,
Join the pedestal of the can package via silver paste. Further, in order to electrically connect the package 150 and the light emitting device main body 100, the package 150 and the light emitting device main body 100 are connected by wire bonding. Thereafter, the cap 170 with the quartz lens 175 is welded to the pedestal 160 to form the airtight package 150.
In this embodiment, the package 150 is not limited to an airtight package such as a can package, but may be a surface mount type using resin sealing or a ceramic package.

<Effect of this embodiment>
This embodiment has the following effects.
(1) The distance L1 between the semiconductor chip 10 that emits deep ultraviolet rays and the connection substrate 30 is 10 μm or less and is sufficiently short. Underfill 50 is filled in this short gap. Thereby, even when the temperature of the semiconductor chip 10 rises to, for example, near 100 ° C., the distance L1 between the semiconductor chip 10 and the connection substrate 30 is short, so that the semiconductor chip 10 is connected to the connection substrate 30 via the underfill 50. It becomes easy to dissipate heat, and the heat dissipation of the semiconductor chip 10 can be enhanced.

Moreover, the average particle diameter of the filler contained in the underfill 50 is 1 μm or less. As a result, the gap between the semiconductor chip 10 and the connection substrate 30 can be filled with the underfill 50 with fewer bubbles (ideally with zero bubbles). Therefore, even when the temperature of the underfill 50 rises, the bubbles can be prevented from expanding, and the expansion of the bubbles can prevent the space between the semiconductor chip 10 and the connection substrate 30 from being expanded. Thereby, it can suppress that force is applied to the joining part of the 1st electrode part 15 and the 2nd electrode part 33 in the direction which releases this joining, and it prevents that a joining part fractures | ruptures and electrical failure arises. be able to.
Therefore, it is possible to provide a light emitting device having high heat dissipation and excellent reliability of electrical connection between the semiconductor chip 10 and the connection substrate 30.

(2) The glass transition temperature of the resin contained in the underfill 50 is 100 ° C. or higher. Thereby, the resin contained in the underfill 50 can expand when the light emitting device main body 100 is energized. Therefore, it is possible to further suppress the force from being applied to the joint portion between the first electrode portion 15 and the second electrode portion 33 in the direction of releasing the joint due to the expansion of the resin.

(3) When the aluminum nitride substrate 11 is viewed in cross section (or side view), the distance L11 between both side surfaces of the first portion 111 is shorter than the distance L12 between both side surfaces of the second portion 112. It has become. The thickness T12 of the second portion 112 is 2 μm or more and 100 μm or less.
As a result, when the semiconductor chips are separated from the aluminum nitride substrate (wafer) on which a large number of semiconductor chips are formed, it is possible to prevent defects such as chipping by a blade or the like from occurring. It is possible to prevent damage to the semiconductor laminated portion 13 immediately adjacent to the first principal surface 11a.

<Modification>
FIG. 1 shows a case where the second electrode portion 33 is not arranged in a region (hereinafter referred to as a facing region) facing the mesa top portion of the semiconductor stacked portion 13 in the first main surface 31a of the ceramic substrate 31. It was. However, the present invention is not limited to this. For example, a part of the second electrode portion 33 may be disposed in the facing region.

  FIG. 5 is a cross-sectional view showing a configuration example of a light emitting device main body 100A, which is a modification of the embodiment of the present invention. As shown in FIG. 5, in the light emitting device main body 100A, a part 331 of the second electrode portion 33 is formed in a facing region of the first main surface 31a of the ceramic substrate 31 facing the top of the mesa of the semiconductor stacked portion 13. Has been placed. The part 331 is a non-joined part that is not directly joined to the first electrode part 15.

  In the light emitting device main body 100A, a gap having a distance L1 'of 10 μm or less is provided between a part 331 of the second electrode portion 33 and the mesa top portion of the semiconductor stacked portion 13. In the light emitting device main body 100 </ b> A, the gap of the distance L <b> 1 ′ is a gap between the semiconductor chip 10 and the connection substrate 30. The gap is filled with underfill 50. Even with such a configuration, the same effects as the effects (1) to (3) of the above-described embodiment are obtained.

Or although not shown in figure, a part of 1st electrode part 15 may be arrange | positioned at the mesa top part of the semiconductor lamination part 13. FIG. A gap with a distance of 10 μm or less may be provided between a part of the first electrode part 15 and a part 331 of the second electrode part 33. In this case, a gap between a part of the first electrode part 15 and a part 331 of the second electrode part 33 is a gap between the semiconductor chip 10 and the connection substrate 30. The underfill 50 may be filled in the gap. Even with such a configuration, the same effects as the effects (1) to (3) of the above-described embodiment are obtained.
<Device>
The device of the present invention comprises the light emitting device of the present invention.
The light emitting device of the present invention can be applied to various devices.
The light-emitting device of the present invention can be applied to and replaced by all existing devices in which an ultraviolet lamp is used. In particular, the present invention can be applied to an apparatus using deep ultraviolet light having a wavelength of 280 nm or less.
The light emitting device of the present invention can be applied to, for example, devices in the medical / life science field, the environmental field, the industrial / industrial field, the life / home appliance field, the agricultural field, and other fields.
The light emitting device of the present invention is a chemical / chemical substance synthesis / decomposition device, liquid / gas / solid (container, food, medical equipment, etc.) sterilizer, semiconductor cleaning device, film / glass / metal surface modification, etc. Equipment, exposure equipment for manufacturing semiconductors, FPDs, PCBs and other electronic products, printing / coating equipment, adhesion / sealing equipment, transfer / molding equipment for films / patterns / mockups, banknotes / scratches / blood / chemical substances, etc. Applicable to measurement / inspection equipment.
Examples of liquid sterilizers include automatic ice making equipment, ice trays, ice storage containers, water storage tanks for ice making machines, ice making machines, freezers, ice making machines, humidifiers, dehumidifiers, water server cold water tanks, hot water tanks, flow paths Pipes, stationary water purifiers, portable water purifiers, water heaters, water heaters, wastewater treatment devices, disposers, toilet drainage traps, washing machines, dialysis water sterilization modules, peritoneal dialysis connector sterilizers, disaster water storage systems, etc. This is not the case.
Examples of gas sterilizers include air purifiers, air conditioners, ceiling fans, floor and bedding vacuum cleaners, futon dryers, shoe dryers, washing machines, clothes dryers, indoor sterilization lights, and storage ventilation. Examples include, but are not limited to, systems, shoe boxes, and chests.
Examples of solid sterilizers (including surface sterilizers) include vacuum packers, belt conveyors, medical / dental / barber / beauty salon hand tool sterilizers, toothbrushes, toothbrush holders, chopstick boxes, cosmetic pouches, Examples include, but are not limited to, drainage lids, toilet bowl cleaners, toilet lids, and the like.

Next, Examples 1 and 2 of the present invention and a reference example will be described. Note that the present invention is not limited to the first and second embodiments.
<Example 1, Reference Example>
The structure of Example 1 of the present invention will be described. In a single crystal aluminum nitride substrate (that is, an AlN single crystal substrate) in which a semiconductor laminated portion and a first electrode portion are formed on the first main surface, the substrate is polished thinly by 200 μm by grinding the opposing second main surface. . In order to perform the joining by the flip chip method, gold having a thickness of 1 μm was formed on the outermost surface of the first electrode portion by vapor deposition.

In addition, an aluminum nitride substrate with a conductive layer patterned thereon was used as the connection substrate (that is, submount), and bumps for bonding to the semiconductor chip were formed by gold plating. The gold plating was formed so as to have a thickness of 10 μm or more. Further, bumps made of gold (hereinafter, gold bumps) have an interval of 100 μm.
A submount on which a gold bump is formed is placed on a stage, and the first electrode portion (hereinafter referred to as gold) formed on the first main surface of the semiconductor chip while the stage is heated to 200 ° C. while the stage is heated to 200 ° C. , Gold electrode).

  By applying an ultrasonic wave of 500 mW at the time of flip-chip bonding, the gold bump on the submount is crushed, and the gap between the semiconductor chip and the second electrode part on the submount (that is, the top of the mesa of the semiconductor stacked portion is arranged). Further, the distance between a part of the first electrode part and a part of the second electrode part arranged in the opposing region facing the top of the mesa in the submount was 4 μm as shown in FIG. The underfill used had an average filler diameter of 0.1 μm, filtered to a maximum of 1 μm, and a resin glass transition temperature of 127 ° C.

  While the underfill filled in the syringe is heated to 55 ° C, the tip of the dispenser nozzle is placed on the side of the semiconductor chip, and the surface tension is used to underlie the gap (gap) between the semiconductor chip and the submount. Filled with fill. Whereas there are bubbles at the time of filling, a circular contrast can be seen, but in Example 1, it was confirmed that underfill was filled without bubbles even in a gap of 4 μm as shown in FIG.

  Thereafter, curing was performed at 150 ° C. for 2 hours to cure the underfill. This time, a CoS element was die-bonded to a surface-mounting package with silver paste, and the CoS element and the package were electrically connected using a gold wire to produce a light emitting device. Here, two types of light emitting devices with an underfill and light emitting devices without an underfill were created in the above manufacturing process. The light emitting device with underfill is Example 1, and the light emitting device without underfill was used as a reference example.

  The light-emitting device of Example 1 and the light-emitting device of the reference example were each mounted on an evaluation board and put into a 100 mA continuous current test at room temperature to evaluate the electrical characteristics. When continuous energization was performed for 1000 hours, 11 out of 55 short mode defects occurred in the light emitting device without the underfill (reference example). In contrast, all 55 light emitting devices with underfill (Example 1) were normal, and it was confirmed that there was no short circuit failure. When the cause of failure of the light emitting device (reference example) without underfill was confirmed, a short circuit due to breakage of the electrode portion was confirmed.

  From the above results, it was confirmed that filling of the underfill can suppress damage to the joint portion between the electrode portion and the bump. Moreover, when the temperature of the junction part at the time of electricity supply was measured, it was 86 degreeC, and it was confirmed that it is the temperature below the glass transition temperature of an underfill. From this result, it was confirmed that the light emitting device of Example 1 had high reliability.

<Example 2>
The CoS element filled with underfill by the method described in Example 1 is bonded to the upper surface of the pedestal of the TO-39 can package instead of the surface mount package with a silver paste, and the CoS element and the can are formed using a gold wire. The light emitting device was created by electrically connecting the package and then welding a cap with a quartz lens to the pedestal. This light-emitting device is Example 2. Twenty-two light emitting devices of Example 2 were prepared, and a high temperature standing test at 100 ° C. and a continuous current test at a temperature of 55 ° C., a humidity of 85%, and a 100 mA were conducted for 1000 hours. Was confirmed to be zero. From this result, it was confirmed that the light emitting device of Example 2 had high reliability.

<Others>
The present invention is not limited to the above-described embodiments, specific examples, and examples. Based on the knowledge of those skilled in the art, design changes or the like may be added to the embodiments, specific examples, and examples, and the embodiments, specific examples, and examples may be arbitrarily combined, and such changes may be made. Embodiments to which these are added are also included in the scope of the present invention.

  The light emitting device according to the present embodiment can emit deep ultraviolet light having a wavelength of 280 nm or less, for example, and can be applied to a high output and long life UVC-LED that can be used for sterilization. Further, the light emitting device according to the present embodiment is not limited to the UVC-LED, and can be applied to an LED capable of emitting ultraviolet light other than deep ultraviolet light and light other than ultraviolet light (for example, visible light and infrared light). . The light emitting device according to this embodiment is not limited to sterilization applications, and can be applied to various applications such as illumination applications and sensor applications.

DESCRIPTION OF SYMBOLS 10 Semiconductor chip 11 Aluminum nitride board | substrate 11a 1st main surface 11b 2nd main surface 13 Semiconductor laminated part 15 1st electrode part 21 1st semiconductor layer 22 Light emitting layer 23 2nd semiconductor layer 30 Connection substrate 31 Ceramic substrate 31a 1st main surface 31b 2nd main surface 33 2nd electrode part 50 Underfill 100, 100A Light-emitting device main body 111 1st site | part 112 2nd site | part 150 Package 160 Base 160a Upper surface 160b Lower surface 170 Cap 175 Quartz lens 180 External connection terminal 200 Light-emitting device 331 Part of the second electrode portion 33

Claims (6)

A semiconductor having a substrate, a semiconductor stacked portion formed on the first main surface side of the substrate, and a first electrode portion formed on the first main surface side of the substrate and electrically connected to the semiconductor stacked portion. Chips,
A connection substrate having a second electrode portion formed on the first main surface side of the base material,
In a state where the first main surface of the substrate and the first main surface of the connection substrate are opposed, and the first electrode portion and the second electrode portion are in contact with each other,
Between the semiconductor chip and the connection substrate, a gap with a distance of 10 μm or less is provided,
A light emitting device in which the gap is filled with a filler containing a resin and a filler having an average particle diameter of 1 μm or less.   The light emitting device according to claim 1, wherein a main component of the filler is silica.   The light emitting device according to claim 1, wherein the resin is an epoxy resin having a glass transition temperature of 100 ° C. or higher. The substrate has a first part including a first main surface and a second part including a second main surface opposite to the first main surface;
When the substrate is viewed in cross section, the distance between both side surfaces of the first part is shorter than the distance between both side surfaces of the second part, and the thickness of the second part is not less than 2 μm and not more than 100 μm. Item 4. The light emitting device according to any one of Items 1 to 3.   The light emitting device according to any one of claims 1 to 4, wherein the semiconductor stacked portion emits ultraviolet light having a wavelength of 240 nm or more and 320 nm or less when a preset voltage is applied.   An apparatus provided with the light-emitting device as described in any one of Claims 1-5.