JPH11346005A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device capable of taking a surface mounting step by solder reflow technique posing no problem at all. SOLUTION: An optical semiconductor device is provided with a resin package, the first and second inner leads 41 and 51 in parallel or almost in parallel with each other to be extended inward from one end of the resin package, a semiconductor chip 3 bonded onto the inner end of the first lead 41, a wire W connecting the inner ends of this semiconductor chip 3 and the second inner lead 51, the first and second outer leads 42 and 52 while a connecting terminal making the surface contact with a substrate is formed on the first and second outer leads 42 and 52. On such a constitution, the resin package is provided with the first translucent resin package part 21 sealing the inner ends of the first and second inner leads 41 and 42, the semiconductor chip 3 and the wire W on the front end side as well as the second heat resistant resin package part 22 on the base end side.

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 suitably used as a light emitting portion or a light receiving portion of an optical sensor or the like, and more particularly, to an optical semiconductor device which can be mounted on a substrate or the like.

[0002]

2. Description of the Related Art A light emitting diode in an optical semiconductor device has a form called a so-called light emitting diode lamp, and a light emitting diode of such a form is sometimes configured to be surface mountable. FIG. 10 shows a light emitting diode lamp formed so as to be surface mountable. A light emitting diode (LED) chip 3 is built in a substantially cylindrical translucent resin package 2 having a dome-shaped tip. In this resin package 2,
Two leads extend from the bottom thereof, and an LED chip 3 is bonded to the tip of one of the leads 4, and a wire W is provided between the upper electrode of the LED chip 3 and the other lead 5. Are connected by The tip of the one lead 4 has a parabolic portion formed by embossing, and the LED chip 3 is bonded to the bottom of the parabolic portion 4a. Thereby, the light emitted from the LED chip 3 can be effectively radiated toward the front end side of the resin package 2. Also,
The two leads 4 and 5 are formed of a thin metal plate, and portions extending from the bottom of the resin package 2 form external leads 42 and 52. The external leads 42 and 52 are bent in a crank shape, and the distal ends thereof are formed as planar connection terminal portions 42a and 52a. The planar connection terminal portions 42a and 52a extend corresponding to one side surface of the resin package 2.

When the light emitting diode 3 having the above configuration is surface-mounted on the substrate 6 or the like, a so-called solder reflow technique is employed. That is, a solder paste is applied to the conductor pads 8 on the substrate 6 in advance by printing or the like, and the connection terminals 42a, 52a of the external leads 42, 52 correspond to the conductor pads 8, respectively. And place it so that Then, the substrate in this state is introduced into a reflow furnace, heated, and then cooled.

The temperature in the reflow furnace is set to, for example, 200 ° C. or higher in order to promote re-melting of the solder. In the reflow furnace, the solder component in the solder paste is re-melted, the resin solvent component is dissipated, and the solder component is solidified with a decrease in temperature.
An electrical connection is made between the contact pads 52 and the conductor pads 8 on the substrate, and at the same time, a mechanical connection between them is achieved.

[0005]

However, the above-mentioned conventional surface mount type light emitting diode 1 has the following problems.

Since the resin package 2 needs to have a light transmitting property, for example, a transparent epoxy resin is employed. This transparent epoxy resin does not contain a so-called filler component, and thus tends to have a relatively large coefficient of linear expansion. Then, in the cooling process after the resin package thermally expands due to heating by the reflow furnace, the external leads 42, 5 are set at the solder solidification temperature (for example, 183 ° C.).
After the resin package 2 is fixed to the substrate, the resin package 2 continues to be thermally contracted.
Large heat stress acts on the boundary between Due to such thermal stress, the resin package 2 may be cracked along the leads 4 and 5, or the resin package 2 and the leads 4 and 5 may be cracked.
In some cases, moisture or the like may enter the resin package, resulting in malfunction and a significant reduction in life.

[0007] The present invention has been conceived in view of such circumstances, and is characterized by solving the above-mentioned conventional disadvantages.

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, an optical semiconductor device provided by the present invention comprises a resin package, a first internal lead and a second internal lead extending from one end of the resin package in a parallel or substantially parallel relationship with each other. With the lead,
A semiconductor chip bonded to an inner end of the first internal lead; a wire connecting the semiconductor chip to an inner end of the second internal lead; a first internal lead and a second lead A first external lead and a second external lead extending from one end of the resin package to the outside continuously, and the first external lead and the second external lead can come into surface contact with the substrate. An optical semiconductor device in which a connection terminal portion is formed, wherein the resin package has a light transmitting property for sealing the inner ends of the first and second internal leads, a semiconductor chip, and a wire at a tip end side. It is characterized by comprising a first resin package part and a heat-resistant second resin package part surrounding the outer ends of the first and second internal leads on the base end side.

In a preferred embodiment, the second
The resin package portion is opaque and has a light-colored coloring.

In a preferred embodiment, the boundary between the first resin package and the second resin package is concave toward the front end of the resin package.

The semiconductor chip may be a light-emitting element such as an LED chip or a light-receiving element such as a photodiode or a phototransistor.

In the above resin package, the first package on the tip side
The resin package portion is basically formed of a translucent epoxy resin containing no filler component. However,
When a light-emitting element or a light-receiving element is selected as a semiconductor chip, infrared light is emitted to the outside or infrared light is selectively detected so that visible light is not transmitted and infrared light is transmitted. In some cases, a resin that appears black when viewed with the naked eye may be used. In any case, basically,
The translucent epoxy resin is adopted as the material of the first resin package part, and therefore, in this case, its linear expansion coefficient is relatively large.

On the other hand, for the second resin package portion on the base end side of the resin package, for example, white PPS (polyphenylene sulfide) is employed.

In the optical semiconductor device according to the present invention, since a part of the first and second external leads is used as a planar connection terminal portion with respect to the substrate, the resin package can be surface-mounted on an appropriate circuit board or the like. It is configured as a semiconductor device. In this configuration, for example, when the above-described semiconductor device is mounted on a circuit board or the like so as to be used as a light-emitting portion or a light-receiving portion of an optical sensor, a solder reflow method or the like is employed as described above.

In the optical semiconductor device according to the present invention, a second resin package portion made of a heat-resistant resin is disposed on the side of the resin package where the external leads extend. When PPS is employed as the second resin package as described above, its linear expansion coefficient is smaller than that of translucent epoxy resin, or it is heated like epoxy resin because of its heat resistance. There is no softening. Therefore, in the surface mounting by solder reflow, the solidification temperature of the solder (for example, 1
(83 ° C.), even if thermal shrinkage occurs in the second resin package part during the process of decreasing the temperature, the degree is small, and therefore, the boundary between the internal lead and the second resin package part peels off, Occurrence of a situation in which moisture or the like intrudes into the resin package from the outside due to the occurrence of cracks in the second resin package portion is reduced, and the reliability of the optical semiconductor device mounted by solder reflow is improved.

Also, as in the preferred embodiment, the second
The resin package portion is colored in a bright color such as white, and the boundary surface between the first resin package portion and the second resin package portion is concave toward the tip of the resin package. By adopting the light emitting element as the semiconductor chip, by reflecting the light toward the base end side of the resin package among the light emitted from the semiconductor chip toward the front end side, the light is efficiently directed toward the front of the resin package. Light irradiation can be performed. Conversely, even when a light receiving element is used as a semiconductor chip, light from the front of the resin package can be efficiently focused on the light receiving element. In this case, a semiconductor chip may be bonded to the upper surface of the internal lead, and a step of forming a parabolic portion by embossing at the tip of the internal lead as in the conventional example is unnecessary, which is advantageous in cost. Become.

[0018] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the drawings.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an overall perspective view of one embodiment of a semiconductor device according to the present invention, FIG. 2 is a plan view, and FIG. 3 is III-III in FIG.
FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1,
5 to 8 are explanatory diagrams of the manufacturing process, and FIG. 9 is an operational explanatory diagram. In these figures, the same or equivalent members or portions as those of the conventional example shown in FIG. 10 are denoted by the same reference numerals.

As shown in these figures, this optical semiconductor device has a configuration in which an optical semiconductor chip 3 is sealed in a substantially cylindrical resin package 2 having a dome-shaped tip, and a cylindrical axis line is formed. The substrate 6 is oriented horizontally.
And so on. Two metal strip-shaped leads 4 and 5 extend into the resin package 2 from the base end surface of the resin package 2. Here, of the leads 4 and 5, a portion extending into the resin package 2 is called an internal lead, and a portion extending outside the resin package 2 is called an external lead.

The first internal lead 41 and the second internal lead 51 extend substantially horizontally into the resin package 2 while being substantially parallel to each other in plan view. For example, an LED chip 3 as an optical semiconductor chip is bonded to the upper surface of the end.
The LED chip 3 is in a dice shape, and has a whole surface electrode formed on the bottom surface and an electrode pad formed on the upper surface. A wire W such as a gold wire is provided between the upper electrode pad of the LED chip 3 and the second internal lead 51.
Are connected by The active layer of the LED chip 3 emits light when a predetermined current is applied between both electrodes via the leads 4 and 5.

A first external lead 42 which is continuous with the first internal lead 41 and a second external lead 52 which is continuous with the second internal lead 51 are bent in a crank shape, and the ends thereof are connected to the substrate. On the other hand, horizontal connection terminal portions 42a and 52a that can be connected in a planar manner are formed. The height of the connection terminals 42a and 52a in the vertical direction is
It is almost corresponded to the lower side. Therefore, the lower surface of the resin package 2 and the connection terminal portions 42a and 52a of the external leads 42 and 52 come into contact with a horizontal plane.
The optical semiconductor device 1 can be stably mounted on a horizontal surface such as a substrate.

The resin package 2 has a first resin package portion 21 on the distal end side and a second resin package portion 22 on the proximal end side. First resin package 2
Reference numeral 1 denotes an inner end portion of each of the internal leads 41 and 51, an LED chip 3 bonded to the first internal lead 41, a LED chip 3 and a second internal lead 51, which are formed of a translucent resin material. A wire W for connecting between them is built in. As the translucent resin material, an epoxy resin containing no filler component is preferably used. On the other hand, an opaque heat-resistant resin such as PPS is preferably used for the second resin package portion 22 on the base end side, and a boundary surface with the first resin package portion 21 functions as a reflection portion as described later. For this purpose, for example, a bright color such as white is applied. The boundary surface between the first resin package portion 21 and the second resin package portion 22 is concave toward the tip end of the resin package 2, that is, has a parabolic shape.

The semiconductor device 1 having the above-described structure is manufactured through the steps described below using a manufacturing frame 9 as shown in FIG. The manufacturing frame 9 is formed by stamping and pressing a sheet metal material, and includes a side frame portion 10 extending in a longitudinal direction, a first lead portion 4 extending substantially in parallel from the side frame portion 10 and A second lead section 5 is provided. Then, the configuration of the section indicated by the symbol A is formed continuously in the longitudinal direction. Each of the lead portions 4 and 5 is a portion to be each of the internal leads 41 and 51 and the external leads 42 and 52 connected thereto.

As shown in FIG.
A chip bonding step of bonding the LED chip 3 to the tip of the first lead portion 4 of FIG.
A wire bonding step of connecting the upper surface electrode of the ED chip 3 and the tip of the second lead portion 5 with a wire W is performed.

Next, as shown in FIG. 7, a primary molding step for forming the first resin package portion 21 is performed so as to completely seal the LED chip or the wire W at the tip of each lead portion. . As described above, a transparent epoxy resin is preferably used as a resin material for forming the first resin package portion 21, and a so-called transfer molding method is suitably used as a molding method. At this time, the distal end of the resin package portion 21 is formed in a dome shape to provide a function as a lens, and the base end side is also formed in a dome shape. This is because the boundary surface of the second resin package portion 22 formed adjacent to the base end side functions as a reflection parabola.

Next, as shown in FIG. 8, a secondary molding step of forming a second resin package portion adjacent to the base end of the first resin package portion is performed. As a material for forming the second resin package portion 22, as described above, a material having excellent heat resistance and mechanical strength such as white PPS is suitably employed. As a molding method, a transfer molding method is suitably employed as in the primary molding method.

Subsequently, a lead cutting step is performed on the manufacturing frame and a lead forming step is performed to bend the external leads into a crank shape to finally obtain the individual optical semiconductor devices shown in FIGS.

Next, the operation of the optical semiconductor device 1 having the above configuration will be described.

As described above, since the optical semiconductor device 1 can be stably mounted in a planar shape, it can be mounted on the substrate 6 or the like by surface mounting by a so-called solder reflow method. That is, the conductor pads 8 of the substrate 6
Apply cream solder 7 on top by printing etc.
Then, as shown in FIG. 9, the semiconductor device 1 is placed on the substrate 6 while positioning the conductor pads 8 and the connection terminals 42a, 52a of the external leads 42, 52 so as to correspond to each other. Then, the substrate 6 in this state is introduced into a reflow furnace, and then cooled. For solder reflow,
The temperature of the reflow furnace is set to, for example, 200 ° C. or higher. Due to the heat in the reflow furnace, the solder component in the cream solder remelts and the solvent component dissipates. The molten solder is wet by both the conductor pads 8 and the connection terminals 42a and 52a of the external leads 42 and 52. When the solder is cooled and solidified, the semiconductor device 1 is electrically and mechanically connected to the substrate, and the mounting is completed.

When a current is applied to the LED chip 3 through the leads 4 and 5, the active layer emits light. Light is emitted toward the periphery of the semiconductor chip.
Light propagating toward the front of the resin package portion 21 is radiated to the outside from the dome-shaped tip. The dome-shaped tip portion functions as a convex lens and narrows the direction of light emitted from the tip surface of the resin package 2. On the other hand, of the light emitted by the semiconductor chip 3, the first resin package portion 21
Traveling toward the base end of the first resin package portion 2
The light is reflected at the parabolic boundary surface between the first and second resin package portions 22 and is radiated to the outside from the front end portion of the resin package 2. As described above, according to the optical semiconductor device 1 of this embodiment, the light emitted from the LED chip 3 can be efficiently emitted from the front end side of the resin package 2 toward the target.

The coefficient of linear expansion of the translucent epoxy resin forming the first resin package portion 21 is, for example, 11 to 12 × 10
⁻⁵ / ° C., and tends to soften at a temperature equal to or higher than the glass transition point of, for example, about 120 ° C., but the linear expansion coefficient of the PPS forming the second resin package portion 22 is, for example, 6 to 7 ×. Since it is relatively small at 10 ⁻⁵ / and has excellent heat resistance and mechanical strength, it does not soften even when heated to, for example, 200 ° C. or more, which is the set temperature of a reflow furnace.

Accordingly, the portion of the resin package 2 which borders the external leads 42 and 52 is excellent in heat resistance and mechanical strength as described above, and the second resin package 2 having a relatively small coefficient of linear expansion is arranged. In the optical semiconductor device of the present invention, in the cooling process of the surface mounting by the solder reflow method, the boundary between the second resin package portion and the leads 4 and 5 is caused by stress due to the heat shrinkage of the second resin package portion. It is possible to effectively suppress the occurrence of a situation in which water enters the resin package 2 from the outside due to cracking or peeling.

Of course, the present invention is not limited to the embodiment described above. As an optical semiconductor chip to be built in the resin package 2, LE as a light emitting element is used.
In addition to the D chip, a photodiode as a light receiving element,
Alternatively, a phototransistor can be used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of an optical semiconductor device according to the present invention.

FIG. 2 is a plan view of the semiconductor device shown in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is an explanatory diagram of a manufacturing process of the semiconductor device of the present invention.

FIG. 6 is an explanatory diagram of a manufacturing process of the semiconductor device of the present invention.

FIG. 7 is an explanatory diagram of a manufacturing process of the semiconductor device of the present invention.

FIG. 8 is an explanatory diagram of a manufacturing process of the semiconductor device of the present invention.

FIG. 9 is an operation explanatory view of the present invention.

FIG. 10 is a perspective view showing the overall configuration of a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical semiconductor device 2 Resin package 3 LED chip 4, 5 Lead part 21 First resin package part 22 Second resin package part

Claims (5)

[Claims] 1. A resin package, a first internal lead and a second internal lead extending parallel to or substantially parallel to each other from one end of the resin package, and A semiconductor chip bonded to an end, a wire connecting the semiconductor chip to the inner end of the second internal lead, and one end of a resin package connected to the first internal lead and the second lead A first external lead and a second external lead extending from the outside to the outside, and the first external lead and the second external lead are formed with connection terminal portions capable of making surface contact with the substrate. An optical semiconductor device, wherein the resin package has a light-transmissive first resin package that seals inner ends of the first and second internal leads, a semiconductor chip, and a wire at a tip end side. Di unit, characterized in that a second resin package portion of the heat-resistant enveloping outer ends of the first and second inner leads at its base end side, an optical semiconductor device. 2. The optical semiconductor device according to claim 1, wherein the second resin package portion is opaque and is colored in a bright color. 3. The optical semiconductor device according to claim 2, wherein a boundary surface between the first resin package portion and the second resin package portion is concave toward a tip end of the resin package. 4. The optical semiconductor device according to claim 1, wherein said semiconductor chip is a light emitting element or a light receiving element. 5. The optical semiconductor device according to claim 1, wherein said semiconductor device is surface-mounted on a substrate by a solder reflow technique. apparatus.