JP2000174347A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect photoelectric characteristics by connecting the inside and the outside of a recess in a package member electrically through a pair of lead electrodes, connecting the pair of lead electrodes electrically with an optical semiconductor element and then covering a mold sealing member in the recess arranged with the optical semiconductor element with a protective member. SOLUTION: After metal pieces 6, 7 which serve as lead electrodes, are arranged in a die, liquid crystal polymer is injected and insert molded, and then it is cooled to form a package member 1. An LED die 2 is then die-bonded onto the lead electrodes 6, 7 in the package member 1, utilizing silver paste and each electrode of the die bonded optical semiconductor element and the lead electrodes 6, 7 are die-bonded, utilizing a gold wire 3. Subsequently, epoxy resin is injected as a translucent mold member 4 for protecting the LED die 2 and the gold wire 3, and a filmy protective member 5 of polyethylene resin is press molded onto the package member 1, before the epoxy resin is completely cured.

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 in which an optical semiconductor element arranged in a package is sealed with a resin, and more particularly, to an optical semiconductor device having high reliability while maintaining electro-optical characteristics of the optical semiconductor element. The present invention relates to an optical semiconductor device that can further improve the optical semiconductor device.

[0002]

2. Description of the Related Art Today, optical semiconductor devices using optical semiconductor elements have begun to be used in various fields as small and lightweight light emitting elements and light receiving elements which emit light with low power consumption and high luminance. FIG. 4 shows a light-emitting diode as an example of such an optical semiconductor device. In FIG. 4, an LED die 42 as an optical semiconductor element is die-bonded in a concave portion of a package 41 formed of a resin such as a ceramic or a liquid crystal polymer. Lead electrodes 46 and 47 provided on the package
Is exposed inside the concave portion of the package and outside the package, and the electrodes of the LED die arranged in the package and the lead electrodes provided on the package are externally connected to each other by wire bonding using a gold wire 43 or silver paste. They are electrically connected so that current can be supplied. Also, L
For the purpose of protecting the ED die, the lead electrode, the gold wire, and the like from the outside, a mold sealing member 44 is formed in a package recess in which the LED die is arranged.

The mold sealing member is an optical semiconductor element L
It is necessary to select a resin that can efficiently transmit light from the ED die and that does not damage the LED die or the wire bonding part due to thermal expansion of the mold sealing member during driving or soldering of the light emitting diode. Therefore, epoxy, silicone, modified acrylic resin, or the like is used for the mold sealing member. This makes it possible to provide an optical semiconductor device that can be easily handled without deteriorating the characteristics of the optical semiconductor element.

[0004]

However, due to the expansion of the use environment of the optical semiconductor device, the optical and electrical characteristics of the optical semiconductor device tend to decrease depending on the special use environment. In some cases, the optical semiconductor device may not be driven, and the optical semiconductor device having the above configuration is not sufficient, and further improvement is required. In particular, the tendency is strong under a special environment such as a factory using various gases having a high concentration of an organic solvent, sulfur sulfide or oxygen. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable optical semiconductor device without deteriorating photoelectric characteristics even in a special environment.

[0005]

SUMMARY OF THE INVENTION The present invention provides a package member having a concave portion on the surface, at least one pair of lead electrodes for electrically connecting the inside and the outside of the concave portion of the package member, and a pair of lead electrodes each electrically connected to the outside. The optical semiconductor device includes an optical semiconductor element connected to the optical semiconductor element, a mold sealing member in a concave portion in which the optical semiconductor element is arranged, and a protection member that covers the mold sealing member. In particular, it is an optical semiconductor device in which the gas permeability of the protection member is smaller than the gas permeability of the mold sealing member.

Accordingly, it is possible to prevent the invasion of unnecessary gas that deteriorates the optical semiconductor element and the lead electrode without deteriorating the electro-optical characteristics of the optical semiconductor element. The optical semiconductor device according to the second aspect has a film-like shape in which the protective member is bonded by a mold sealing member. Accordingly, it is possible to suppress the invasion of unnecessary gas and stabilize the amount of the mold sealing member, thereby forming an optical semiconductor device having stable optical characteristics with high productivity.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention
The inventors have found that the reliability can be significantly improved irrespective of the use environment by separating the functions of the protective member and the mold sealing member so as to have a specific relationship, and have completed the invention. Although the reliability improvement by the configuration of the present invention is not clear, it is considered that the characteristic deterioration of the optical semiconductor device in a special environment such as a factory is caused by intrusion of unnecessary gas into the optical semiconductor device in a special atmosphere. That is, the optical semiconductor device needs to be molded with a resin capable of sufficiently exhibiting the optical characteristics of the optical semiconductor element because of its characteristics. In addition, it is necessary to select a mold sealing member that does not mechanically damage the optical semiconductor element or the like during its use.

[0008] Such a mold sealing member often has a structure in which bonding between molecules is weak or the distance between molecules is long.
Therefore, gas permeability is high, and a gas such as sulfur sulfide or oxygen alters a wire made of an electrode, a gold wire or the like of an optical semiconductor element constituting the optical semiconductor device by sulfuration, oxidation, or the like. In addition, it is considered that the surface of some optical semiconductor elements is melted to accelerate the deterioration of the optical semiconductor device. According to the present invention, the reliability can be improved by forming the mold sealing member for protecting the optical semiconductor element and the protection member for preventing gas from entering into the concave portion of the package by separating the functions.
Hereinafter, specific examples of the present invention will be described in detail, but needless to say, the present invention is not limited thereto. Embodiment 1 FIG. 1 is a schematic sectional view of an LED device according to one embodiment of the present invention. FIG. 2 is a perspective view of an LED element according to an embodiment of the present invention, and FIG. 1 is also a cross-sectional view taken along line AA. Hereinafter, formation of an LED element will be described as an example of such an optical semiconductor device.

First, after metal pieces 6 and 7 serving as lead electrodes are arranged in a mold, a liquid crystal polymer is injected and insert-molded. After cooling, the package member 1 was formed by taking it out of the mold. At this stage, the package has a plurality of openings on a plane. The formed package member had an opening substantially at the center, and the lead electrodes were exposed from the bottom surface of the opening and from the side surface to the back surface of the package member. As a material for such a package member, it is desirable to use a material which is excellent in insulating properties and which can be easily formed relatively strong against external force. Ceramics, as specific materials for package members
It is preferable to use a material such as a liquid crystal polymer or a PBT resin. The package member may be mixed with a coloring pigment depending on the characteristics of the optical semiconductor element to be colored in a desired color. Also, one or more LED dies, which are light emitting elements, can be provided as optical semiconductor elements in the package,
The light emitting element and the light receiving element can be arranged at the same time.

Since the lead electrodes 6 and 7 are to be electrically connected to the outside of the package to the optical semiconductor element disposed in the recess, those having excellent electric conductivity are preferable. As a specific material of the lead electrode, a metallized metal such as nickel or a good electrical conductor such as phosphor bronze can be used. Further, the surface of such a material is plated with silver or gold or the like, and is used as an electrode member.
The surface can be used as a light reflecting member so that the light from the ED die is efficiently emitted to the outside.

An LED die 2 is die-bonded on a lead electrode inside the formed package by using a silver paste. When the LED die has a semiconductor layer formed through a pair of electrodes, the LED die can be electrically connected together with the die bond. Various types of such optical semiconductor elements can be used as desired. Specifically, as an LED die capable of emitting a long wavelength region of ultraviolet light or visible light,
Light emitting devices with nitride semiconductors formed on a sapphire substrate, next to aluminum, gallium and indium formed on a gallium arsenide substrate capable of emitting infrared light from the long wavelength region of visible light, and light receiving devices using silicon Can be

Each electrode of the die-bonded optical semiconductor element and the lead electrodes 6 and 7 are wire-bonded using the gold wire 3 which is a good conductor. Thus, the optical semiconductor element and the lead electrode are electrically connected. As the electric good conductor, an aluminum wire or the like other than the gold wire can be used. Next, epoxy resin was injected as a translucent mold member 4 to protect the LED die and the electric conductor. It is required that the resin serving as the mold member protects the optical semiconductor element, has high insulating properties, and has a light transmitting property. Specifically, a relatively soft resin having a hardness of from JIS A hardness of 20 to Shore D hardness of about 80 is preferable so that the wire bonding portion is not broken by its own thermal deformation. More specifically, as the mold member, a translucent sealing resin made of an epoxy-based, silicone-based, or modified acrylic-based resin is preferable. The mold member is preferably made of a coloring agent that cuts light from the optical semiconductor element or light to the optical semiconductor element as desired, a diffusing material that diffuses light, and a fluorescent substance that converts light into desired light. Can also be contained. The above-mentioned epoxy resin was cured at 120 ° C. for 3 hours to form a film-shaped mold member. This is 2
When the transmittance was measured at 3 ° C. by a differential pressure gas permeability test method, it was about 6500 cc / m ² · 24 hrs · atm.
Met.

Next, using a plate heated to 120 ° C. before the epoxy resin is completely cured, a polyethylene resin film-like protection member 5 having a thickness of about 100 μm is formed by a hot stamping method on a plurality of LED die. The package was formed by pressing on a package having an opening.
Since the mold sealing member 4 was still in a flexible state, it was easy to adhere the film-shaped protection member 5. When the above polyethylene resin was subjected to a differential pressure gas permeability test, about 198
cc / m ² · 24 hrs · atm.

The protective member which is a feature of the present invention uses a member having a lower gas permeability than the molded member. The protection member itself does not need to cover the LED die or the like to protect it mechanically, but the Shore D8 has relatively high hardness against external force.
It is preferably 0 or more. In particular, since the protective member does not directly destroy the LED die itself due to thermal expansion or thermal contraction, a relatively dense resin that does not easily allow gas to permeate is preferably used. Specific examples include unsaturated polyester, polyethylene, polymethylpentene, fluororesin and the like.
In particular, the gas permeability is 1000 cc / m ² · 24 hrs ·
Atm or less is preferable. More preferably 30
0 cc / m ² · 24 hrs · atm or less. Also,
About 10 to 15 when the protective member is formed in a film shape
Preferably, the thickness is about 0 μm. This allows
Even a hard film-shaped protective member can follow the deformation of the mold sealing member without peeling or cracking. Further, the gas permeability can be controlled by various conditions such as temperature, solvent, and material when forming the protective member.

FIG. 3 shows an LE according to an embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view before cutting a package element of a D element, but grooves 31 and 32 are formed in the vicinity of each opening so as to be easily divided into LED elements later. This groove also has the effect of making the thickness of the mold member constant by allowing the excess mold member to flow by pressure. The package member was cut together with the protective member along the groove to form an LED element. (Comparative Example 1) A light emitting diode as an optical semiconductor device was formed in the same manner as in Example 1 except that the mold member was cured at 120 ° C for 3 hours without using a protective member. The formed LED elements showed almost the same light emission luminance.

The LED device of Comparative Example 1 and the LED of Example 1
Each of the devices was exposed to a sulfide gas in 700 pieces for 500 hours. When the light output change of the LED element before and after the test was measured, the conventional LED element had an average of 3 after the test compared to before the test.
4% decrease in light output, whereas LED according to the present invention
The light output of the device was reduced by only about 7% after the test as compared to before the test. When the LED element whose output after the test was greatly reduced was disassembled and examined, the wire and the electrode of the LED die were sulfided, changed to black and deteriorated, and the LED element according to the present invention was compared with Comparative Example 1. It was confirmed that the LED element was extremely excellent in reliability.

The mounting of the LED element of Example 1 and the LED element of Comparative Example 1 using a mounter nozzle made of cemented carbide was repeated 10 times with the mounter using the mounter nozzle. In the LED element of Example 1, many scratches with a depth of about 10 μm were found at the nozzle contact portion on the element surface, whereas no surface damage was observed in the LED element according to Example 1, and the LED element according to the present invention was a conventional LED element. It was also confirmed that the LED element was extremely resistant to damage.

[0018]

As described above, by providing the mold member for covering the optical semiconductor element and the protective member for preventing the intrusion of gas which damages the LED die and the like covered with the mold member, the photoelectric member is provided with a photoelectric function. An extremely reliable LED element can be obtained without damaging the characteristics.

In the optical semiconductor device of the present invention, the film-shaped protective member is hot-stamped to eliminate the uneven surface of the resin to flatten the optical characteristics and stabilize the optical characteristics, and at the same time, to keep the amount of the mold member constant. You can also.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an LED device according to one embodiment of the present invention. 2 shows a cross section taken along line AA of FIG. 2.

FIG. 2 shows a perspective view of an LED device according to one embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an LED device before cutting a package member according to an embodiment of the present invention.

FIG. 4 is a schematic sectional view of an LED element shown for comparison with the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Package member 2 ... LED die 3 ... Wire 4 ... Mold sealing member 5 ... Film-shaped protective member 6, 7 ... Electrode member 31, 32 ... Groove part 33 ... Mold sealing member 41 ... Package member 42 ... LED die 43 ... Wire 44 ... Mould sealing member 46, 47 ... Electrode member

Claims (2)

[Claims] A package member having a concave portion on the surface;
At least a pair of lead electrodes for electrically connecting the inside of the concave portion of the package member to the outside, an optical semiconductor element electrically connected to the pair of lead electrodes, and a concave portion in which the optical semiconductor element is arranged. An optical semiconductor device comprising: a mold sealing member; and a protective member that covers the mold sealing member, wherein the gas permeability of the resin that forms the protective member is less than the gas permeability of the resin that forms the mold sealing member. An optical semiconductor device, wherein the optical semiconductor device has a smaller gas permeability. 2. The optical semiconductor device according to claim 1, wherein said protective member is a film bonded by a mold sealing member.