JPS60157284A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the titled device of stable performance to be manufactured with good yield by a method wherein a section of solder adhesion in such a manner that the side surface of a semiconductor substrate is almost even with that of an intermediate member is provided on the intermediate member, and a region imparted with the wetting property to solder is provided in the neighborhood of the adhesion part of the side surface of the intermediate member. CONSTITUTION:The semiconductor laser substrate 2 is die-bonded on the intermediate member 3 with Au-Sn solder, and the main surface of the substrate 2 is provided with an electrode layer whose uppermost layer is an Au layer. Besides, the intermediate member 3 is adhered on a supporting member 1 with Pb-Sn series solder. A conduction path constituent member 5 is connected to the other conductive member from the electrode layer in the upper side of the substrate 2, and the other electrode in the lower side of the substrate 2 is connected to the other conductive member via copper relay plate 6. The intermediate member 3 has a metallized layer 33 on its side surface 31 and is imparted with the wetting property to solder. This enables the solder to flow out of the layer 33, producing no swelling at the end part because of sagging. Therefore, the cut-off of a laser light path or the short circuit of a P-N junction does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor device, and particularly to a semiconductor device that has excellent heat radiation and provides stable performance.

[Background of the invention]

Semiconductor laser elements, which are an example of semiconductor devices, have recently attracted attention, particularly in the field of optical communications. Other than the fact that the output level is lower than that of non-semiconductor light emitting devices, this has the following advantages: (1) low power driving possible, (2) direct modulation possible, (3) high efficiency possible, and (4) long life. (5) Small size and light weight. Semiconductor laser elements include, for example, GaAs, GaP, and GaA'RA.
A Pn junction formed in this material is made of a semiconductor single crystal material such as a ■-■ group compound represented by S, InGaAsP, etc., or a IV-Vl group compound represented by PbSSe, Pb5nTe, etc. A forward current is applied to the cell, and the injected carriers recombine to emit light.
A portion of the light generated by this is returned to the light emitting region near the junction by a reflecting mirror, and this returned light further promotes carrier recombination and new light emission. By repeating the stimulated emission process, the laser is emitted. This is intended to lead to oscillation.

In order to increase the efficiency of this type of semiconductor laser device,
It is effective to lower the threshold current that leads to laser oscillation, but to do so, it is necessary to effectively confine carriers excited by the injection current in the light emitting region, effectively confine stimulated emission light, and reduce the interaction between photons and carriers. It needs to be acted upon and promoted. However, even with such measures, the oscillation threshold current density still reaches about 1 to 3 KA/c♂ when continuous oscillation is performed at room temperature, for example.
Naturally, heat is generated at the joint, and in order to achieve stable laser oscillation, it is necessary to efficiently cool the semiconductor laser body or efficiently dissipate the heat generated in the semiconductor laser body. . At the same time, due to the heat generation and cooling cycles associated with the operation and rest of the semiconductor laser element, the bonding interface between the semiconductor laser substrate and the support member for mounting the substrate is caused by thermal strain due to the difference in the thermal expansion coefficients of both components. This leads to thermal fatigue failure, for example, the formation of cracks in the adhesive layer. Such an adhesive layer doubles as a part of the main heat dissipation path of the semiconductor laser body and also serves as an electrical conductor area, which may cause the laser body itself to overheat and become unable to conduct electricity, thus preventing stable laser oscillation. It becomes difficult to continue.

In order to overcome the above-mentioned problems, conventionally, as shown in FIG. 1, a diamond strip having excellent thermal conductivity and having a coefficient of thermal expansion approximately similar to that of the semiconductor laser substrate 2 was placed on a metal support member 1 made of steel or the like. A structure was adopted in which the semiconductor laser substrate 2 was bonded via an intermediate member 3 such as the one shown in FIG. At this time, the semiconductor laser substrate 2 is placed on the end 31 of the intermediate member 3 in order to facilitate optical coupling between the laser element and the light receiving element or the optical fiber cable that relays between the laser element and the light receiving element. At the same time, in order to improve heat dissipation efficiency, p is used as a heat source.
The n-junction 21 is placed close to the heat radiation path and bonded using a brazing material. A metallized layer 32 is provided on the intermediate member 3 to maintain adhesive strength to the intermediate member 3 and at the same time provide wettability to the brazing material. The intermediate member 3 is generally brazed onto the metal support member 1 using a material such as gold thread solder such as Au-8iy Au-Ge or Au-5n or Pb-Sn based solder. Further, the semiconductor laser base 2 includes a conductive path forming member 5, an electrode layer that enables electrical and mechanical connection between the member 5 and the semiconductor laser base 2, and an electrical and mechanical connection between the semiconductor laser base 2 and the intermediate member 3. An electrode layer is provided that provides wettability to the brazing material in order to make a positive connection. As the brazing material between the semiconductor laser substrate 2 and the intermediate member 3, a material of the same quality and type as the above-mentioned brazing material is used.

Furthermore, in addition to the semiconductor laser base 2, a relay metal plate 6 for electrical connection to the conductive path forming member 5 is bonded on the intermediate member 3 in the same manner as the semiconductor laser base 2.

Since a pn junction is usually formed in the semiconductor laser substrate 2 by an epitaxial growth method or a diffusion method, the light emitting region is formed not at the center in the thickness direction of the substrate but at a portion extremely close to the surface. However, in order to increase heat dissipation efficiency, a structure is adopted in which the surface of the semiconductor laser substrate 2 on which the pn junction is formed is brazed onto the above-mentioned intermediate member 3.
This causes the following problems. The first problem is that the optical path of the laser light emitting part is cut off by the soldering of the semiconductor laser base 2, and the second problem is that the laser light emitting part has to be cut in the wall so that it becomes an ideal reflecting surface. It is formed by pn
Since the bond is exposed, the bond is short-circuited by the brazing filler metal. The cause of such a problem is that the brazing material is discharged to the end of the bonded portion between the semiconductor laser substrate 2 and the intermediate member 3, and the brazing material bulges up.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device having a structure that improves the above-mentioned problems and allows semiconductor devices with stable performance to be manufactured at a high yield.

[Summary of the invention]

A semiconductor device of the present invention that achieves the above object has a semiconductor substrate having a pair of principal surfaces facing each other and a side surface perpendicular to the two principal surfaces. On an intermediate member made of an inorganic insulator or an inorganic semiconductor having at least one substantially right-angled side surface, a portion is bonded using a brazing material so that the semiconductor substrate and the side surface of the intermediate member are located on substantially the same plane. The intermediate member is characterized in that a side surface of the intermediate member is provided with a region imparted with wettability to the brazing material at least in the vicinity of the adhesive portion.

[Embodiments of the invention]

The present invention will be explained in detail below using examples.

FIG. 2 shows a semiconductor laser device according to an embodiment of the present invention.

In the figure, the same or equivalent parts as in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description thereof will be omitted.

In FIG. 2, on a gold-plated copper support member 1,
Semiconductor laser substrate 2 containing GaA (lAs) formed by epitaxial growth on GaAs
(0.3mm x 0.3mn x thickness 0.1mm) is Si
They are bonded via an intermediate member 3 made of a C strip. This SiC strip has a thickness of 0.8+nm x 1.6nwn x 0.
3, with Cr-N formed by vapor deposition on both main surfaces.
An i-Au multilayer metallization J132 is provided, and on the side surfaces 31, substantially perpendicular to the two main surfaces, a homogeneous metallization layer 33 extending from the metallization layer 32 is provided. The semiconductor laser substrate 2 is die-bonded onto the intermediate member 3 using Au-Sn solder. An electrode layer whose uppermost layer is an Au layer is provided on the main surface of the semiconductor laser substrate 2. Moreover, the intermediate member 3 is made of Pb-8n on the support member 1.
It is bonded with a solder material. The conductive path forming member 5 is made of an Au wire with a diameter of 30 μm, and is connected from the electrode layer on the upper side of the semiconductor laser body 2 to other conductive members by thermocompression bonding, while other electrical areas on the lower side of the semiconductor laser body 2 are It is connected to other conductive members by the conductive path forming member 5 via the gold-plated steel relay plate 6. The important point here is that a metallized layer 33 is provided on the side surface 31 of the intermediate member 3 extending from the metallized layer 32 to provide wettability to the brazing material between the semiconductor laser substrate 2 and the intermediate member 3. This is what is being done.

With this structure, the brazing material protrudes from the edge of the semiconductor laser substrate 2 and then flows out onto the metallized layer 33 and hangs down, so that it does not bulge at the edge. Therefore, there is no possibility that the optical path of the laser beam emitting section is cut off or the pn junction is electrically shorted. To quantitatively illustrate this effect, when the conventional structure shown in Fig. 1 was adopted, the failure rate due to optical path interruption and Pn junction short circuit was about 5%, whereas with the structure shown in Fig. 2 of the present invention, the failure rate was about 5%. When adopted, the defective rate was reduced to 0.05% or less. In addition, in the conventional structure, consideration was given to reducing the amount of brazing filler metal used in order to reduce the swelling at the end of the filler metal between the semiconductor laser substrate 2 and the intermediate member 3, but this has the opposite effect on the semiconductor laser substrate 2 and the intermediate member 3. This induces incomplete adhesion between the laser body 2 and the intermediate member 3.

However, in the structure of the present invention, there is no need to reduce the amount of brazing filler metal so that the above-mentioned adhesion is completely achieved. For example, in the case of the structure shown in FIG.
% or more, whereas in the structure shown in FIG. 2 of the present invention, it was low at about 0.905%.

Table 1 also shows the composition of the material for the intermediate member 3 applied to the semiconductor laser device of other embodiments of the present invention, the portion corresponding to the metallized layer 33 when it is made into a composite layer, and the metal forming the portion corresponding to the solder 4. It is.

a first layer in contact with SiC, a second layer in contact with the first layer,
The second layer and the third layer in contact with the solder were formed by vapor deposition in various combinations shown in the table. Even in this case, exactly the same effect as in the above embodiment was obtained.

Furthermore, the metal configuration in Table 1 is A as the material for the intermediate member 3.
Q20: l, AQN, Bed, Si, N4゜MgO,
When applied to ceramics such as diamond, Si,
Even when applied to semiconductors such as Ge and SiC, the same effects as in the above embodiments were obtained.

Next, FIG. 3 is a sectional view illustrating an embodiment of the method for manufacturing the intermediate member 3 in the method for manufacturing a laser diode of the present invention. 3A shows a SiC plate 300 with a thickness of 0.3 mm, which was obtained by hot pressing a mixed powder containing SiC powder and a small amount of BeO powder at 2050° C. in a vacuum. The SiC plate 300 obtained in this way has a relative density of 98% or more and a thermal conductivity of 0.7 cal/cm・
It has thermal conductivity of ℃・S, which is comparable to that of metal. SiC board 3
00 has principal surfaces 301 and 302 that are parallel to each other. A groove 304 having a surface 303 substantially perpendicular to the main surface 301 of this SiC plate 300 was formed. The groove 304 has a width of about 50 pm and a depth of about 150 μm, and was formed by polishing with a rotating grindstone. Next, metallized layers 32 were formed on the main surfaces 301 and 302 by vacuum evaporation. At this time, main surface 3
During vapor deposition on the 01 side, the metallized layer 33 is also formed around the side surface 303 of the groove 304. Thereafter, polishing using a rotating grindstone was performed so that the grooves 303 penetrated through the SiC plate 300. The groove width at this time was 30 μm. Furthermore, a through groove is formed in a direction perpendicular to the groove 303 to form a strip-like (
0.8mm Xl, G nwn X thickness 0.3in)
An intermediate member 3 was created. The metallization layer 32.33 is Cr:
0.05pm, Ni: 0.4pm, Au
: Formed in a 0.5 μm laminated structure. onwards,
A semiconductor laser base (0.3 mm x 0.3
++raX thickness 0.1 iin) 2 and the Au-plated steel relay plate 6 were bonded together using an Au-Sn brazing filler metal. The atmosphere in this case is a mixed gas of nitrogen gas to which several percent of hydrogen gas is added, and the bonding temperature is 280°C. Further, the intermediate member 3 was bonded with a PB-8N solder material, and the conductive path forming member 5 was wire bonded to complete the semiconductor laser device.

Although the details of the present invention have been explained above using Examples, the present invention can also be implemented in the following embodiments.

First of all, the material for the intermediate member 3 mentioned above does not need to be SiC, and may be, for example, Si, Ag2O3, diamond Be.
An inorganic insulator or an inorganic semiconductor such as O, etc. can be applied, and the metallized layers 32 and 33 do not need to be metals formed by vapor deposition, for example, metallized layers formed by thick film firing known as the Telefunken method, or sputtering. The metallized layer may be formed by a method or a vapor phase growth method. Also, the groove 304
In addition to the method using a rotating grindstone, for example, a method using a laser beam, a sandblasting method, an ultrasonic processing method, etc. can be applied as a forming method or a dividing method.

Further, the semiconductor device of the present invention is not limited to a laser diode, and the present invention is particularly effective when a pn junction is exposed on the side surface of a semiconductor substrate.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to manufacture a semiconductor device with high performance and stability at a high yield.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a conventional semiconductor device, FIG. 2 is a diagram for explaining a semiconductor device according to an embodiment of the present invention, and FIG. 3 is a diagram for explaining a method for manufacturing a semiconductor device according to an embodiment of the present invention. It is. DESCRIPTION OF SYMBOLS 1... Metal support member, 2... Semiconductor laser base, 3
... Intermediate member, 5... Conductive path component, 6... Relay metal plate, Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Scope of Claims] 1. A semiconductor substrate having a pair of mutually opposing main surfaces and a side surface perpendicular to the above-mentioned bidirectional surfaces, the semiconductor substrate having a pair of mutually opposing main surfaces and a side surface substantially perpendicular to the above-mentioned bidirectional surfaces. On an intermediate member made of an inorganic insulator or an inorganic semiconductor having at least one side surface, a portion is bonded using a wax so that the semiconductor substrate and each side surface of the intermediate member are located approximately on the same plane. ,
1. A semiconductor device characterized in that a side surface of an intermediate member includes a region imparted with wettability to the brazing filler metal at least in the vicinity of an adhesive portion. 2. In claim 1, the intermediate member is made of SiC.
, AQ, 20. , AQN, B eo, Si: + N4t
Ceramic or S i y G e 5Si made of at least one material selected from the group consisting of MgO, C
Cr, which is a semiconductor made of at least one material selected from the group C, and which is in contact with the ceramic or semiconductor at least in the vicinity of the semiconductor substrate bonding part on the side surface of the intermediate member;
Ti, AQ, Mo, Ni. A first material made of one material selected from the group consisting of W and Ag.
layer, and Cr and Ti in contact with the first layer. AQ, Mo, Ni, Cu, Ag, Pd, Pt. a second layer made of l material selected from the group consisting of Au, and A g +Au, Pt in contact with the second layer and the brazing material;
A semiconductor device comprising a metal region in which a third layer made of one material selected from the group consisting of: is sequentially laminated.