JPH09307145A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve characteristic efficiency and reliability, by forming a smooth surface in an arrangement part in which at least an optical semiconductor element of a package electrode is arranged, and making a connecting part to which a conducting wire is connected into a rough surface. SOLUTION: An LED chip 104 wherein a light emitting layer using a gallium nitride based semiconductor is laminated on a light transmission insulating substrate 107 is used as an optical semiconductor element. The light transmission insulating substrate 107 of the LED chip 104 and a package electrode are bonded and fixed. An optical semiconductor element whose surface is electrically connected with an outer circuit is electrically connected with an electrode on the package electrode. The package electrode fixing the LED chip 104 and the vicinity are made a smooth surface 102, and an package electrode to which a conducting wire is connected by bonding and the vicinity are made a rough surface 101. Therefore, high output and/or high sensitivity and high reliability can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device such as a light emitting diode or an optical sensor using an optical semiconductor element, and more particularly to an optical semiconductor device having excellent optical characteristics and excellent reliability. .

[0002]

2. Description of the Related Art Today, optical semiconductor devices using a light-receiving element that converts light into electricity or a light-emitting element that converts electricity into light are used in various environments, and there is an increasing demand for higher performance. . Examples of such an optical semiconductor device include a level meter, a display, a backlight, an optical sensor and a solar cell. The optical semiconductor device is used by accommodating a light emitting element or a light receiving element which is an optical semiconductor element in a package which is a resin protector or the like in order to protect it from external force, moisture, dust and the like. Electric power from the outside is supplied to the optical semiconductor element via a package electrode provided on the package, an electrical connection member, or the like, or conversely, electric power is supplied from the optical semiconductor element to the outside to drive the optical semiconductor device. In order to improve the utilization efficiency of such an optical semiconductor device, it is necessary to effectively use the light that enters or is emitted from the optical semiconductor element. That is, it is conceivable to increase the reflectance of the electrode on which the optical semiconductor element is arranged so that the surface has a high reflectance. Japanese Patent Application Laid-Open No. 62-76577 can be cited as one that defines such electrode surface roughness.

On the other hand, some semiconductors are arranged on a translucent insulating substrate in order to make effective use of reflected light or fixed on a package electrode with a resin which is a translucent insulator. Such an optical semiconductor device is different from the above-described optical element in that each electrode of the optical semiconductor element and the package electrode are electrically connected using a conductive wire or the like in order to reduce size, weight, improve productivity and reliability. Need to be connected. FIG. 3 shows a specific example of an optical semiconductor device in which each electrode of such an optical semiconductor element and a package electrode are electrically connected by a conductive wire. This optical semiconductor device has a package electrode having a smooth surface on the package, and an optical semiconductor element is fixed on the package electrode by using a paste. Each electrode of the optical semiconductor element is electrically connected to each package electrode by a conductive wire. Thereby, an optical semiconductor device having high efficiency can be obtained.

[0004]

However, the optical semiconductor device having the above configuration is not sufficient in the present day when efficiency improvement and reliability are required, and further higher brightness and lower power consumption are achieved even in an environment where temperature and humidity change greatly. / Or high sensitivity and low noise and reliability are required. In view of the above problems, the invention of the present application is to provide an optical semiconductor device having a highly efficient characteristic and high reliability of the optical semiconductor device.

[0005]

According to the present invention, there is provided an optical semiconductor element arranged in a package, a conductive wire for connecting one electrode of the optical semiconductor element to a first package electrode, and the optical semiconductor element. Has a second package electrode disposed via a translucent insulator, and a conductive wire electrically connecting the other electrode of the optical semiconductor element to the second package electrode, and at least the above. An optical semiconductor device in which an arranging portion of the second package electrode where the optical semiconductor element is arranged has a smooth surface, and at least a connecting portion to which the conductive wire of the second package electrode is connected is a rough surface. .

The smooth surface is 0.1 S or more and 0.8
S or less optical semiconductor device, the rough surface is 1.6S or more and 10
It is also an optical semiconductor device of S or less. Furthermore, the optical semiconductor device is an optical semiconductor device in which the optical semiconductor element is a light emitting element, and the optical semiconductor device is also in an optical semiconductor device in which the translucent insulator is a paste resin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various experiments by the present inventor,
It has been found that the optical characteristics and reliability of the optical semiconductor device depend on the unevenness of the electrode surface on which the optical semiconductor element is provided and the electrode surface to which the electrical connection member is connected, and based on this, the present invention has been completed.

The improvement of the characteristics by the structure of the present invention is achieved especially when the fixing surface of the optical semiconductor element and the fixing surface of the electrical connecting member for electrically connecting the optical semiconductor element and the electrode are formed on the package electrode. If the change becomes large, the fixed surface of the optical semiconductor element and the adhesive strength of the electrical connection member are reduced because of the same electrode surface, and thus the characteristics of the optical semiconductor device become unstable, or the desired characteristics are not obtained, or It is considered that the optical semiconductor device may not function in some cases. Further, it is considered to be particularly remarkable in the case of a light emitting element in which the optical semiconductor element itself generates heat.

According to the present invention, a smooth electrode surface is provided near the optical semiconductor element to be fixed, and a rough electrode surface is provided near the electrical connection member to be connected, and the functions are separated. This makes it possible to improve the optical characteristics immediately below the optical semiconductor element, improve the adhesiveness of the conductive wire and the optical semiconductor element itself, and obtain a compact and lightweight optical semiconductor device with high reliability and efficiency.

The surface roughness of the package electrode surface on which the optical semiconductor element of the present invention is fixed via the translucent insulator is
By setting it to 0.1 S or more and 0.8 S or less, it is possible to prevent the peeling of the optical semiconductor element and improve the utilization efficiency of light from or to the optical semiconductor element. The surface roughness of the package electrode to be bonded is 1.6S.
When it is 10 S or less, the bonding strength can be increased and the adhesion can be improved. Furthermore, the adhesive strength of the optical semiconductor element can be improved by suppressing the fluidity that occurs when the fixing paste for the optical semiconductor element is cured. Hereinafter, an example of the present invention will be described with reference to the drawings.

1 and 2 are schematic views showing an optical semiconductor device of the present invention. L in which a light emitting layer using a gallium nitride-based semiconductor is laminated on a transparent insulating substrate such as sapphire
The ED chip is used as an optical semiconductor element. The translucent insulating substrate of the LED chip and one of the package electrodes are bonded and fixed with an epoxy resin or the like. The surface of the gallium nitride-based semiconductor device, which is an optical semiconductor device, is electrically connected to an external circuit, etc., through a gold wire, which is a conductive wire, on the package electrode where the optical semiconductor device is placed. It is electrically connected to one of the electrodes.
In addition, the other electrode is connected to another package electrode via a gold wire which is a conductive wire. Part of the light emitted from the light emitting layer of the optical semiconductor element is transmitted through the translucent insulating substrate, reflected by the package electrode, and the reflected light can be effectively used. Since the package electrode to which the LED chip, which greatly contributes to the reflection of light, and the vicinity thereof are made into a smooth mirror surface, the reflectance of the light led out below the LED chip is extremely high, and the light outside the package is highly reflected. The take-out efficiency is significantly increased. On the other hand, by forming the package electrode to which the conductive wire is connected by bonding and the vicinity thereof as a rough surface, the anchor effect that the wire bites into the rough surface is also synergized and the wire bonding strength is increased. Therefore, the optical semiconductor device has high reliability. Further, as shown in FIG. 2 (B), by providing a rough surface adjacent to the smooth surface on which the LED chip is fixed, the spread of the die bond resin having increased fluidity at the time of curing is reduced due to the rough surface, so that the LED chip and the package The amount of resin that is adhesively fixed to the electrodes is increased, and the adhesiveness can be further improved.

The inventor of the present invention has variously changed the surface roughness of the package electrode in the optical semiconductor device in the portion where the LED chip is mounted and its vicinity and the portion where the conductive wire is bonded and its vicinity. It was prepared, and the light output was measured and the thermal cycle test was conducted, and the result is shown in FIG. The A curve in FIG. 4 is the result of measuring the relationship between the surface roughness and the light output of the portion where the LED chip is mounted and its vicinity. The surface of the conductive wire joint portion of the measurement sample is fixed at 5 S for all the samples. From the curve A, it was found that the light output increased as the surface roughness of the portion where the LED chip was mounted and its vicinity was smaller. The curve B in FIG. 4 is the result of measuring the surface roughness of the wire joint and the number of cycles until the joint breaks in the thermal cycle test. From the B curve, it can be seen that as the surface roughness of the wire joint increases, the number of cycles leading to fracture also increases and the reliability increases. Note that both the A and B curves are curves obtained by approximating and connecting each plot point obtained from the test results. The curve A is LE
The optical output of the optical semiconductor device is 100% when the average surface roughness of the electrode on the part where the D chip is mounted and its vicinity is 0.8S.
Is a relative display of the light output. Similarly, the B curve is a relative display of the number of fracture cycles with 100% as the number of cycles until the joint breaks in the thermal cycle test when the average roughness of the electrode surface of the conductive wire joint is 1.6S. It was done. In FIG. 4, the portion on which the LED chip is mounted and the electrode surface in the vicinity thereof are in the region on the left side of the line C in the figure, which proves that the light utilization efficiency can be extremely increased. It is also supported by the fact that the reliability of the optical semiconductor device can be made extremely high by the fact that the electrode surface of the conductive wire bonding portion is in the region to the right of the line D in the figure. Hereinafter, each configuration of the present invention will be described in detail.

(Smooth surface and rough surface of package electrode 10
1, 102, 201) The smooth surface and the rough surface of the present invention are
The degree of unevenness of the package electrode surface can be measured by a non-contact method such as a laser microscope. Specifically, the roughness of the measurement surface can be determined by finding the unevenness of the measurement surface by the focus position by searching the focus of the reflected light while scanning the measurement surface with laser light.
In the package electrode surface on which the optical semiconductor element of the present invention is fixed via the translucent insulator, the surface roughness is preferably
It is 0.1 S or more and 0.8 S or less, more preferably 0.
1 S or more and 0.5 S or less, more preferably 0.1 S or more and 0.3 S or less. By setting it to 0.1 S or more and 0.8 S or less, it is possible to prevent the peeling of the optical semiconductor element and improve the utilization efficiency of light from or to the optical semiconductor element. That is, the light reflection efficiency can be improved on a smooth surface of 0.1 S or less, but under an environment where the temperature and humidity cycle is severe, the resin or the like for fixing the optical semiconductor element to the package electrode is likely to be peeled off. on the other hand,
When it is 0.8 S or less, the reflection efficiency can be improved.

The package electrode surface to which the conductive wire which is the electrical connection member of the present invention is connected is preferably
1.6S or more and 10S or less, more preferably 5S
Or more and 10 S or less, more preferably 7.5 S or more and 10 S or less. By setting it to 1.6 S or more and 10 S or less, it is possible to increase the adhesive strength of a metal wire or the like and suppress the fluidity of the resin paste during curing. Since the bottom surface to which the optical semiconductor element is fixed has high smoothness, suppressing the flow of the resin paste by the rough surface can significantly improve the adhesion. Therefore, even in environments with severe temperature and humidity cycles, metal wires and LE
The adhesion of the D chip can be improved.

Such a rough surface is produced by first making the entire package electrode a smooth surface, and then masking the vicinity of the die-bonded portion where the optical semiconductor element is fixed, and etching or shot blasting the package electrode. It can be formed relatively easily by adding a treatment for roughening the surface of the electrode. Alternatively, it can also be formed by masking the wire bonding portion of the electrode having a rough surface as a whole, and finishing the portion where the optical semiconductor element is mounted and the vicinity thereof by electropolishing into a mirror surface. The rough surface and the smooth surface can be formed as desired by variously selecting the etching time, the etching solution, the blasting time, the blasting material or the electropolishing time, and the polishing agent.

(Package Electrode) The package electrode used in the present invention is for supplying the power from the outside of the package to the optical semiconductor element arranged inside or for supplying the power inside the package to the outside. . Therefore, it may have various shapes as desired, and may be formed by extending from the package, or may be integrally formed. On at least one package electrode, an optical semiconductor element is arranged and an electrical connection member electrically connected to the electrode of the optical semiconductor element is connected. The package electrodes can be formed in various sizes as desired. When the optical semiconductor element is a light emitting element, the package electrode preferably has good thermal conductivity in order to dissipate the heat emitted from the optical semiconductor element to the outside while disposing the optical semiconductor element. Further, since the optical semiconductor element is arranged on the package electrode, the reflectance is preferably high in order to effectively use the light emitted from the light emitting element. As such a package electrode, a copper-based alloy such as copper or phosphor bronze, an iron-based alloy, or a base metal such as metalized nickel plated with a noble metal such as gold or silver is preferably used. Various types of such package electrodes can be used depending on the electrical conductivity and the thermal conductivity, but a plate thickness of 0.1 mm to 2 mm is preferable from the viewpoint of workability.

(Package 103) Package 103
Has an electrode that fixes and protects the light emitting element and / or the light receiving element in the concave portion and that can be electrically connected to the outside. Further, the package may have a translucent protective member or the like housed in the recess of the package to further protect the optical semiconductor element and the electrical connection member from the external environment. Therefore, the package is required to have good adhesiveness to the translucent protective member and higher rigidity than the translucent protective member. Further, in order to improve the adhesiveness with the translucent protective member and to direct the force exerted by the translucent protective member at the time of thermal expansion to the outside, the tubular portion may be shaped like a mortar that expands outward.
Further, in order to accommodate and use a light emitting element having a spectral characteristic for visible light, it is preferable that the light emitting element is colored to have a light shielding function.

Further, it is desired to have an insulating property in order to electrically shut off the optical semiconductor element from the outside. Furthermore, when the package is affected by heat from the optical semiconductor element or the like, it is preferable that the package has a small coefficient of thermal expansion in consideration of the adhesion with the protective body. The inner surface of the package can be embossed to increase the adhesion area, or plasma-treated to improve the adhesion with the protector.

Polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, epoxy resin, phenol resin, acrylic resin, PBT resin, glass epoxy and the like can be used as such a package. The package has a package electrode on which a light emitting element can be placed in advance and can be electrically connected to one electrode of the light emitting element, and each electrode that can be connected to the other electrode of the light emitting element. Therefore, the package may be formed integrally with the electrode, or the package may be divided into a plurality of pieces and combined by fitting or the like. Such a package can be formed relatively easily by insert molding or the like.

(Optical semiconductor element 104) Examples of the optical semiconductor element 104 used in the present invention include a light receiving element and a light emitting element formed of various semiconductors. As the light receiving element, Ge or S formed by utilizing the liquid crystal growth method is used.
Those using a single crystal semiconductor such as i, InAs, CdS or a polycrystalline semiconductor. Si, SiC formed by various CVD methods using energy such as plasma, heat, and light,
Examples thereof include optical sensors using microcrystals such as SiGe and amorphous semiconductors, solar cells, and the like. As the structure of the semiconductor, various ones such as a homo structure or a hetero structure having a PN junction or a PIN junction can be mentioned. Various light receiving wavelengths of the light receiving element can be selected depending on the material of the semiconductor and the degree of mixed crystal thereof. Glass,
A light-receiving element can be formed by forming a semiconductor having the above-described configuration in a desired size on a heat-resistant resin or a metal substrate and making electrical connection. As the electrode of the light receiving element, various metals such as Al, Ag and Au formed by sputtering or vacuum deposition, metal oxides such as ITO, SnO2 and ZnO2, and n ⁺ semiconductor can be used.

On the other hand, as a light emitting device, a liquid phase growth method or MO
GaAlN, ZnS, ZnS on the substrate by the CVD method etc.
e, SiC, GaP, GaAlAs, AlInGaP,
An LED, LD, or the like in which a semiconductor such as InGaN, GaN, or AlInGaN is formed as a light emitting layer is used. 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. The emission wavelength can be variously selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Further, the light emitting layer may have a single quantum well structure or a multiple quantum well structure to have a quantum effect.
A desired electrode is formed on the thus-formed semiconductor by using various vapor deposition methods such as vacuum deposition, sputtering, heat, light, and discharge energy. In the case of a light emitting device, a semiconductor wafer on which the above electrodes are formed is directly full-cut by a dicing saw in which a blade having a diamond blade is rotated, or after cutting a groove having a width wider than the blade width (half-cut). ), The semiconductor wafer is broken by an external force. Alternatively, an extremely thin scribe line (meridian) is drawn on the semiconductor wafer, for example, in a checkerboard pattern by a scriber in which a diamond needle at the tip reciprocates linearly, and then the wafer is cut by an external force and cut into chips from the semiconductor wafer.

When the light emitting element is used outdoors, it is preferable to use gallium nitride compound semiconductors for green and blue as the high-luminance semiconductor material, and gallium / aluminum / arsenic semiconductors and aluminum for red. -It is preferable to use an indium-gallium-phosphorus-based semiconductor, but needless to say, it can be variously used depending on the application.

A plurality of the optical semiconductor elements thus formed can be arranged in the package as desired. For example, the light emitting element and the light receiving element are arranged in the same package, or two blue light emitting elements having different emission wavelengths are used.
For example, one green and one red can be used. Further, the emission wavelength is not necessarily limited to blue, green, and red, and the band gap of the semiconductor may be adjusted so that yellow or the like can be emitted as desired. As a specific example, a yellow LED sandwiched between blue-green LED chips
A chip can be used to emit white light. For full-color light emission, an optical semiconductor element that emits RGB light emission colors can be used. In order to obtain a full-color emission color, the emission wavelength of R (red) is 600 nm to 700 nm, and the emission wavelength of G (green) is 495 nm to 5 nm.
65 nm, B (blue) emission wavelength is 430 nm to 49
It is preferably 0 nm.

The optical semiconductor element formed on the translucent insulating substrate may be adhesively fixed to the package electrode using an adhesive such as Ag paste in order to improve heat dissipation.

(Conductive Wire 105) The conductive wire 105 used in the present invention is for electrically connecting each electrode of the optical semiconductor element and the package electrode. Therefore, it is required to have good adhesion and electric conductivity to the electrodes of the optical semiconductor element and the package electrodes. Conductive wires can be connected relatively easily by wire bonding equipment. The conductive wire is
Various selections can be made depending on the electrode material of the optical semiconductor element, the package electrode material, and the like, but gold wire or the like is preferably used because it is easy to handle.

(Translucent Protective Member 106) The translucent protective member 106 protects the LED chip which is the optical semiconductor element 104, the optical sensor and wires for electrical connection thereof from external force, dust and water. It is provided to do. Therefore, the translucent protective body and the light emitting element may be formed in close contact with each other, or may not be in close contact with the light emitting element for heat dissipation and stress relaxation. Further, the translucent protective body may be divided into two or more layers, if desired, such as a multilayer structure of layers having different transmittances. As a material for such a translucent protective body, specifically, an epoxy resin, a urea resin, a silicon resin, a fluororesin, a polycarbonate resin, an acrylic resin, or the like is preferably used. Hereinafter, specific embodiments of the present invention will be described in detail, but it is needless to say that the present invention is not limited to only the specific embodiments.

(Translucent Insulator 107) The translucent insulator 107 used in the present invention has an insulating property and is substantially translucent or semitransparent in the wavelength sensitivity at which the photoelectric conversion element emits or receives light. It is a thing. Therefore, it may be a translucent insulating substrate on which a semiconductor is formed, or an adhesive for fixing a semiconductor element to a package electrode. The translucent insulating substrate on which the semiconductor is formed is suitably used depending on the semiconductor to be formed, but for the gallium nitride based semiconductor, a sapphire substrate or the like is preferably used. Specific examples of suitable adhesives include thermosetting resins such as epoxy resins, acrylic resins and imide resins. Further, it goes without saying that a translucent insulating substrate bonded with a translucent resin also serves as a translucent insulator.

[0028]

【Example】

[Example 1] An LED chip having a blue emission color was used as an optical semiconductor element. An LED chip was constructed using InGaN (emission wavelength 470 nm) as a semiconductor light emitting layer of the light emitting device. Specifically, N-type and P-type gallium nitride compound semiconductors are deposited to a thickness of 5 μm and 1 μm respectively on a sapphire substrate having a thickness of 400 μm by MOCVD growth method to form a heterostructure PN junction. The P-type gallium nitride semiconductor is formed by doping Mg which is a P-type dopant and then annealing. Next, after forming electrodes by sputtering using Mg as a P-type electrode and Al as an N-type electrode so as to be the respective electrodes of the LED chip, a scribe line is drawn on the semiconductor wafer by a scriber to apply an external force. The LED chip is constructed by cutting into a size of 350 μm square.

As a package electrode, a phosphor bronze plate was silver-plated to form a smooth surface. The smooth surface at this time is
It is 0.5S. Next, the vicinity of the portion where the LED chip was die-bonded was masked with a resist, and the surface in the vicinity where the wire was connected was roughened by shot blasting. The rough surface of this portion is 7.5S. After removing the mask, the package electrode having the smooth surface and the roughened surface was insert-molded in the liquid crystal polymer to form a package in which the surface of the package electrode was exposed in the package recess and the outer bottom surface. The LED chip was fixed on the package electrode provided in the recess in the package by epoxy resin using a die bonder at 120 ° C. for 15 hours. Diameter 0.03mm using wire-honding equipment
Au wire was wire-bonded to each electrode of the LED chip, the package electrode on which the LED was placed and subjected to the surface roughening treatment, and the package electrode to be the other electrode. Next, a non-colored epoxy resin as a translucent protective body was filled in the concave portion in the package and cured at 120 ° C. for 16 hours. In this way, 100 optical semiconductor devices in which the LED chips were encapsulated were formed.

A current of 20 mA was passed through this optical semiconductor device, and its average optical output and -30 ° C for 1 hour and 85 ° C for a humidity of 85%.
The 1-hour temperature-humidity cycle test was repeated 500 times. After the temperature / humidity cycle test, a current of 20 mA was applied to examine the presence or absence of light emission. The output / reliability index shown by the product of the light output and the reliability (the number of heat and cold cycles) is shown in Table 1 together with Comparative Example 1, Comparative Example 2 and Comparative Example 3.

Comparative Example 1 100 optical semiconductor devices were formed in the same manner as in Example 1 except that a package electrode having an average surface roughness of 0.5S was used. The average output / confidence index was examined in the same manner as in Example 1.

Comparative Example 2 100 optical semiconductor devices were formed in the same manner as in Example 1 except that a package electrode having an average surface roughness of 7.5 S was used. The average output / confidence index was examined in the same manner as in Example 1.

Comparative Example 3 100 optical semiconductor devices were formed in the same manner as in Example 1 except that a package electrode having an average surface roughness of 4.0 S was used. The average output / confidence index was examined in the same manner as in Example 1.

Example 2 As a package electrode, a phosphor bronze plate with the entire surface of the electrode roughened was used. The rough surface at this time is
It is 7.5S. The periphery of the optical semiconductor element as the wire bonding portion of each electrode was concentrically masked with a resist, and the portion where the LED chip and the optical sensor were mounted and the vicinity thereof were electropolished to be mirror-finished. The unevenness of the smooth surface is 0.1S. After removing the mask, the roughened and smoothed package electrodes were formed. Each package electrode was insert-molded in a liquid crystal polymer to form a package in which the package electrode surface was exposed in the package recess and the outer bottom surface.

An optical sensor having an amorphous silicon light receiving layer formed on a glass substrate by a plasma CVD method as an optical semiconductor element, and an LED chip having a gallium nitride semiconductor light emitting layer formed on a sapphire substrate by a liquid crystal growth method, Was fixed and cured with an epoxy resin by a die bonder on the smooth surface of the package electrode provided in the recess in the package. At this time, the rough surface of the epoxy resin acted as a dam to suppress the flow. A light-shielding portion that separates the light-receiving element from the light-emitting element is formed at the center of the electrode. Using wire-honding equipment, diameter of 0.
A wire of 03 mm of Au wire was wire-bonded to the respective electrodes of the LED chip and the optical sensor and the rough surface of the package electrode. Next, a non-colored epoxy resin as a translucent protective body was filled in the concave portion in the package and cured at 120 ° C. for 16 hours.

In this way, the photo interrupter as an optical semiconductor device in which the LED chip and the optical sensor are enclosed is
00 pieces were formed. The formed optical semiconductor device is the first embodiment.
As well as showing good optical characteristics, it has excellent reliability.

As described above, according to the structure of claim 1 of the present invention, in the optical semiconductor device, the roughness of the package electrode surface on which the optical semiconductor elements are stacked is adjusted to a portion where high reflectance is required, that is, light High output and / or high sensitivity and high reliability as a smooth surface in the vicinity where the semiconductor element is mounted and a rough surface to increase the bonding area and the anchoring effect in the wire bonding part where bonding strength is required. Can be Further, by adopting the configuration of claim 2 of the present invention, it is possible to provide an optical semiconductor device having more excellent light emission efficiency and / or light receiving sensitivity. With the configuration according to claim 3 of the present invention, it is possible to provide an optical semiconductor device having excellent characteristics even under a more severe environment of use. With the structure according to claim 4 of the present invention, an optical semiconductor device having good characteristics can be provided even in an optical semiconductor device in which the optical semiconductor element itself generates heat. With the configuration according to claim 5 of the present invention, it is possible to provide an optical semiconductor device having excellent characteristics even under conditions of a severer usage environment by suppressing the flow at the time of curing the resin for fixing the optical semiconductor element.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an optical semiconductor device of the present invention,
1A is a schematic plan view of the optical semiconductor device.
FIG. 1B is a sectional view taken along line xx of FIG.

2 is a schematic sectional view of another optical semiconductor device of the present invention, FIG. 2 (A) is a schematic plan view of the optical semiconductor device,
2B is a cross-sectional view taken along line xx of FIG.

3 is a schematic plan view of an optical semiconductor device for comparison with the present invention, FIG. 3 (A) is a schematic plan view of an optical semiconductor device, and FIG. 3 (B) is FIG. 3 (A). FIG.

FIG. 4 is a diagram showing the results of measurement of how the smoothness and roughness of the electrode surface affect reliability and reflectance. 4A shows the relationship between the surface roughness and the light output of the portion where the optical semiconductor element is mounted and its vicinity, and FIG.
B of shows the relationship between the surface roughness of the wire joint and the number of cycles until the joint breaks in the thermal cycle test.

[Explanation of symbols]

101 ... Package electrode (rough surface portion) of wire joining portion 102 ... Package electrode (smooth surface portion) in the vicinity of the LED chip fixing portion 103 ... Package electrode supporting member (package body) 104 ... LED Chip 105 ... Wire led out from LED chip surface 106 ... Package mold sealing member 107 ... Translucent insulator 201 ... Package electrode (rough surface portion) at wire junction 302 ... Package Electrode 303 ... Package electrode support member (package body) 304 ... LED chip 305 ... Wire led out from LED chip surface 306 ... Package mold sealing member

[Table 1]

Claims (5)

[Claims] 1. An optical semiconductor element arranged in a package, a conductive wire for connecting one electrode of the optical semiconductor element to a first package electrode, and the optical semiconductor element via a translucent insulator. And a conductive wire that electrically connects the other electrode of the optical semiconductor element to the second package electrode, and at least the optical semiconductor of the second package electrode. An optical semiconductor device, wherein an arrangement portion in which an element is arranged has a smooth surface, and at least a connection portion to which the conductive wire of the second package electrode is connected is a rough surface. 2. The optical semiconductor device according to claim 1, wherein the smooth surface is 0.1 S or more and 0.8 S or less. 3. The optical semiconductor device according to claim 1, wherein the rough surface is 1.6 S or more and 10 S or less. 4. The optical semiconductor device according to claim 1, wherein the optical semiconductor element is a light emitting element. 5. The optical semiconductor device according to claim 1, wherein the translucent insulator is a paste resin.