JPH04278593A - Photoelectric device and manufacture thereof - Google Patents

Abstract

PURPOSE:To use a submount of inexpensive copper so as to improve heat dissipating effect and to reduce a cost of a photoelectric device associated with an AlGaInP semiconductor laser (LD) element. CONSTITUTION:An LD element 5 is fixed on a submount 1 of copper in which peripheries of front and rear surfaces are lowered at one stage, in a state that a front end 9 slightly protrudes from a front edge 7a of the stage. The submount is formed by providing grooves 45 in a lattice state on front and rear surfaces of a plated copper plate 40 by etching and then cutting at the grooves by dicing. The end of a burr 3 at the time of dicing does not protrude from the groove, thereby eliminating a disturbance in the case of securing the LD element, etc. The securing accuracy of the element to be conducted with the end of the submount as a reference is high due to the dicing accuracy. Since the edge 2a of the stage of the groove becomes a substantially perpendicular section by etching, heat radiation of the emitting surface of the element is effectively conducted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optoelectronic devices and methods of manufacturing the same.

0002

2. Description of the Related Art Semiconductor laser elements of various structures have been developed as light sources for optical communications or for information processing devices such as digital audio disks (DAD) and video disks. A semiconductor laser (laser diode: LD) generates a large amount of heat during its operation. Therefore, efficient heat dissipation is also important in the structural design of optoelectronic devices incorporating semiconductor laser devices. Further, since the semiconductor laser element is small in length, width, and height of 0.4 mm or less, it is handled by being fixed on a support called a submount in order to improve its handling. Such a semiconductor laser element is fixed to a stem or the like within a package of an optoelectronic device via a submount.

[0003] As an example of mounting semiconductor lasers for communication at low cost, for example, "Nikkei Electronics" published by Nikkei BP, September 24, 1984 issue, P265-P294.
“SiC ceramics have begun to be applied to LSI packaging; A
Utilizes a thermal conductivity that exceeds that of l and a coefficient of thermal expansion that is close to that of Si”
285 and P286. This document describes that a SiC (silicon carbide) submount is fixed on a Cu (copper) stem with Pb/Sn (lead/tin) solder, and a laser chip (semiconductor) is fixed on the SiC submount with Pb/Sn solder. An example in which a laser element (laser element) is fixed is shown. In addition, the same document states, ``Synthetic diamond has traditionally been used as a submount material in highly reliable communication semiconductor lasers... However, the biggest problem today is that diamond is extremely expensive. There is.''

GaAlAs (with an oscillation wavelength of 780 nm)
Semiconductor lasers for digital audio disks composed of (gallium, aluminum, arsenic) systems are described, for example, in "Nikkei Electronics", September 14, 1981 issue, pages 138 to 152, published by Nikkei BP. This document states, ``Since the semiconductor laser chip is small, at most 0.1 x 0.3 x 0.2 mm, it is necessary to
Mount it on a mm square submount board. The submount substrate may be made of Cu or Si. ...Si has a thermal expansion coefficient close to that of GaAs. For this reason, a hard Au-Sn based or Au-Si based brazing filler metal (solder) with a high melting point can be used. The brazing filler metal is hard, so care must be taken when mounting it, but it is said to withstand long-term storage at high temperatures. On the other hand, when using a Cu submount, a soft In brazing material is used to absorb the difference in thermal expansion coefficient. When In brazing filler metal is used, the initial strain is small. However, due to concerns about deterioration, the combination of In brazing filler metal and Cu submount is becoming rarer. A Si or Cu submount substrate is mounted on a Cu post (some are integrated with the stem). This also serves as a heat sink. ”, and the submount is made of Si or Cu.
It is stated that it is used. The same document also states, ``When mounting a semiconductor laser chip on a submount substrate, the factory standard is that the dimensional accuracy between the resonator end face and the submount substrate edge is +3 μm and -0 μm. This is because if the laser beam is placed deeper than the edge, it will be vignetted by the mount board.''

On the other hand, regarding visible light semiconductor lasers with an oscillation wavelength in the 0.6 μm band, see “Electronic Materials” 1 published by Kogyo Kenkyukai.
January 986 issue, published January 1, 1986, P86-P
93. This document describes AlGaInP (
A photograph of an aluminum-gallium-indium-phosphorus semiconductor laser device fixed to a diamond heat sink is disclosed. In addition, the same document shows the temperature characteristics of the oscillation threshold current, and in the explanation section of this characteristic, it states, ``Figure 12 shows the temperature characteristics of the laser. Characteristic temperature in mode (To
) is 122 to 133K, and oscillation is possible up to 145°c in pulse mode and up to 60°c in CW mode. The CW oscillation threshold current density is 3.8 kA/cm2 on average and 3.8 kA/cm2 on average.
6kA/cm2 (cavity length 200-250μ
m). ” is also stated.

On the other hand, the temperature characteristics of AlGaInP-based semiconductor lasers are worse than those of GaAlAs-based semiconductor lasers, as described in (H.C. Casey, Jr., M.B. Pan).
ish HETERO STRUCTURE L
ASERS, 1987, PART, B, P. As described in P44, the bandgap (AlGaInP
and GaInP (energy cap Eg difference) is small, Inst. Phys. Conf. Ser. No.
106: Chapter 8, P. P575, 1990, the carrier concentration cannot be increased.

[0007]

[Problems to be Solved by the Invention] Conventionally, Si has been used as a submount for semiconductor laser devices such as GaAlAs. High SiC, AlN
, diamond, etc. are used.

The present inventor examined the suitability of the material and processing of the submount to be used in an optoelectronic device incorporating an InGaAlP semiconductor laser element in terms of productivity and cost. Although the Si submount is cheap in terms of cost, its thermal conductivity is 125 W m-1 ° according to the above literature.
K-1, room temperature, 60-170W m-1 of AlN
・°K-1, room temperature, 270W m-1 of high thermal conductivity SiC
・°K-1, room temperature, 60 to 490 W・m of SiC single crystal
-1・°K-1, room temperature, 900 to 200 of diamond
0 W·m−1·°K−1, which is low compared to room temperature, cannot be used in optoelectronic devices incorporating semiconductor laser elements with large thermal resistance. Furthermore, AlN, SiC, and diamond are expensive. The thermal conductivity of copper for the copper submount is 394W・m−1・°
K-1, room temperature, high thermal conductivity, superior in heat dissipation properties than SiC and AlN, and has the advantage of being inexpensive. However, as pointed out in the above-mentioned literature, there is a concern about the deterioration of the In brazing material used to bond the semiconductor laser element and the submount, and therefore copper submounts tend not to be used. Additionally, based on the applicant's experience, the workability of extremely thin copper plates (copper foil) using conventional cutting methods is not necessarily good and is not suitable for mass production. Not used.

[0009] Therefore, the inventor of the present invention once again studied the selection of the material of the submount and the development of processing technology, and completed the present invention. In other words, the only way to improve heat dissipation and reduce material costs is to use inexpensive metals instead of ceramics or diamonds, such as AlN and SiC, which are expensive and do not necessarily have good workability. do not have. Furthermore, in this case, it is necessary to develop a new processing technology that solves the problems with conventional cutting methods described below.

[0010] Hereinafter, features of the conventional processing method for forming a metal submount investigated by the present inventors and problems in assembling a semiconductor laser element of the submount manufactured using the method will be explained. Copper is used in the manufacture of submounts. The copper plate (copper foil) used as the material is, for example, about 0.1 to 0.2 μm, since submounts having the same thickness as conventional submounts are manufactured. As processing methods to be considered, press processing, etching processing, and dicing processing will be explained.

In press working, as shown in FIGS. 9 and 10, due to shearing of the metal, rounding (sagging) 3 and protrusions (burrs) 4 are generated on the edge 2 of the submount 1. This roundness 3 and protrusion 4 are difficult to correct if they occur, partly because the submount 1 is thin. When the semiconductor laser element 5 is brought to one end of the submount 1 and fixed via the solder 6, the roundness of the front edge 7 of the submount 1 is A space 10 may be generated between the rounded portion 3 of the submount 1 and the front end 9 of the semiconductor laser device 5, or a space 10 may be generated between the rounded portion 3 of the submount 1 and the front end 9 of the semiconductor laser device 5 compared to the submount 1. Since the solder 6 having a lower rate is thicker than the others, the dissipation of heat generated in the vicinity of the emission surface 12 of the laser beam 11 is lowered, and the temperature characteristics are deteriorated. Further, the submount 1 to which the semiconductor laser element 5 is fixed is fixed to a stem or the like, and the protrusion 4 of the submount 1 is attached to the fixing surface of the stem.
As a result, the submount 1 is tilted and fixed, and the direction in which the laser beam 11 is emitted changes.

In the case of FIG. 10 in which the semiconductor laser element 5 is fixed to the side of the submount 1 with the protrusion 4, the front end 9 of the semiconductor laser element 5 rests on the protrusion 4, so that the semiconductor laser element 5 is It is tilted and fixed, and the emission direction of the laser beam 11 changes. In addition, since the semiconductor laser element 5 is tilted, the distance between the semiconductor laser element 5 and the submount 1 becomes wide in some parts, and voids 13 are generated in the solder 6, or the fixing solder 6 is partially removed. If the film becomes thick, uniform heat dissipation cannot be achieved, which adversely affects the light emitting characteristics.

In the etching process, as shown in FIG. 11, no rounding 3 is generated on the edge 2 of the submount 1, and the edge has a substantially right-angled cross section. However, due to cutting by etching,
A protrusion 14 remains in the middle portion of the end surface of the submount 1. The protrusion length (a) of the protrusion 14 changes due to variations in the thickness of the submount 1 and variations in the etching process. When fixing the semiconductor laser element 5 to the submount 1, one end surface of the submount 1, that is, the tip of the protrusion 14 serves as a reference plane, and the semiconductor laser is automatically moved to the dimensional position set with respect to this reference plane. Element 5 is fixed. As a result, as shown in FIG. 12, when the protrusion length of the protrusion 14 is shorter than the specified length (m), the front end 9 of the semiconductor laser element 5 is located inside the front edge 7 of the submount 1. A solder 6 is located at and fixes the semiconductor laser element 5.
overflows to the emission surface side of the semiconductor laser element 5, and a raised portion 15 is likely to occur. In the case of a so-called junction down method in which the semiconductor laser element 5 is fixed with the junction that emits the laser beam 11 facing downward, the raised portion 1
5 becomes an obstacle to the laser beam 11 emitted from the emission surface 12, causing an adverse effect on the light emission characteristics. Moreover, if the raised portion 15 falls off, it becomes a foreign substance and exists inside the package of the optoelectronic device, which is not desirable in terms of reliability as it may cause short-circuit defects.

Further, as shown in FIG. 13, when the protrusion length of the protrusion 14 is l longer than the specified length (m), the front end 9 of the semiconductor laser element 5 is longer than the front edge 7 of the submount 1. As in the case where the semiconductor laser element 5 is protruded and the semiconductor laser element 5 is fixed on the side of the rounded surface 3 described above, a space 10 is generated between the rounded part 3 and the semiconductor laser element 5, or the solder 6 is partially thickly interposed. Therefore, the temperature characteristics deteriorate. Note that, as described in the above literature, when the semiconductor laser element 5 is fixed to the submount 1, the front end 9 of the semiconductor laser element 5 is fixed so as to protrude from the front edge 7 of the submount 1 by about 0 to 20 μm. Ru.

In the case of dicing, projections (burrs) 4 are formed on the edges of the front and back surfaces of the submount 1, as shown in FIG.
occurs, and as explained in Fig. 10, the temperature characteristics decrease,
This causes inconveniences such as deviation in the direction of laser light emission. In addition,
If the processing conditions are set to make the burr 4 generated by dicing as short as possible, the burr length will be 0.015.
It has also been confirmed that the thickness can be reduced to about 0.02 mm or less.

[0016] Therefore, the inventor of the present invention came up with the idea of developing a composite processing means that utilizes the advantages of these various processing methods, and accomplished the present invention.

An object of the present invention is to provide an optoelectronic device incorporating a submount that has excellent heat dissipation properties and can achieve cost reduction, and a manufacturing technique thereof.

Another object of the present invention is to provide a submount that allows the assembly of optoelectronic devices without substantially changing conventional assembly techniques.

Another object of the present invention is to provide an optoelectronic device incorporating an AlGaInP semiconductor laser element and having good thermal characteristics.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0021]

[Means for Solving the Problems] A brief overview of typical inventions disclosed in this application is as follows. That is, AlGaInP of the present invention
In an optoelectronic device incorporating a visible light semiconductor laser, the semiconductor laser element is fixed to a copper submount. This copper submount is manufactured by etching grooves in a lattice pattern corresponding to the front and back surfaces of a copper plate whose front and back surfaces are coated with a desired plating, and then cutting the copper plate at the groove portions by dicing. As a result, the circumferences of the front and back surfaces of the submount are lowered one step further. Then, the edge due to this step is formed into a substantially right-angled cross section by etching. Furthermore, dicing is performed in such a way that the generation of protrusions (burrs) is suppressed as much as possible, and the tips of the burrs generated during dicing are prevented from protruding outside the groove, that is, on the front and back surfaces of the submount. Furthermore, the semiconductor laser element fixed on the submount is fixed via solder so that the end on the side of the emission surface that emits laser light, that is, the front end slightly protrudes from the edge of the step by about 0 to 20 μm. has been done.

[0022]

[Function] As described above, the optoelectronic device of the present invention uses SiC,
Since a submount made of copper, which is cheaper than AlN, diamond, etc., is used, cost reduction can be achieved.

The optoelectronic device of the present invention has stable temperature characteristics. In other words, copper has a lower thermal conductivity than diamond, but it has a thermal conductivity that is more than twice that of Si and 2 to 2 times that of AlN.
The thermal conductivity is more than 6 times that of SiC, which is more than 3 times that of SiC. Therefore, even in an optoelectronic device having a structure in which an AlGaInP semiconductor laser element with high thermal resistance is fixed on a copper submount, the thermal characteristics are good. As a result, when this optoelectronic device is used as a light source in a laser beam printer to draw a long solid line, its good thermal characteristics prevent the light output from gradually decreasing while drawing the solid line. ,
The last part of the drawn solid line can be drawn with the same density as the front part.

The optoelectronic device of the present invention has high heat dissipation properties due to the shape of the submount. That is, in the submount, the edge around the chip mounting surface is formed into a substantially right-angled cross section by etching. Then, the front end of the semiconductor laser element on the emission surface side is fixed to the edge portion. Therefore, the heat at the front end of the semiconductor laser element is quickly transferred via the solder to the highly thermally conductive submount and further to the support such as the heat sink or stem, resulting in good thermal characteristics of the optoelectronic device. .

Although the optoelectronic device of the present invention uses a copper submount, it can be assembled without any problem in manufacturing the optoelectronic device. In other words, because this submount employs a combined processing method using etching processing and diamond processing in its manufacture, there are protrusions on the front and back surfaces of the submount that may interfere with fixing the semiconductor laser element or fixing the submount. Does not stand out. Therefore, the semiconductor laser element and the submount will not be tilted due to the protrusion, and the direction of laser light emission will not be misaligned. Furthermore, the generation of voids in the solder and the phenomenon of partial thickening of the solder film caused by the inclination of the semiconductor laser element and the submount are prevented, and heat dissipation is improved.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of essential parts showing a fixed state of a semiconductor laser element in an optoelectronic device according to an embodiment of the present invention, and FIG. 2 shows a manufacturing state of a submount used in manufacturing the optoelectronic device according to an embodiment of the present invention. 3 is a cross-sectional view of the same copper plate, FIG. 4 is a perspective view of the submount, and FIG. 5 is a diagram showing the positioning of the submount when fixing a semiconductor laser element to the submount in the manufacture of optoelectronic devices. 6 is a side view showing the state in which the semiconductor laser element is fixed to the submount, FIG. 7 is a sectional view showing the state in which the submount is held, and FIG. 8
1 is a partially cutaway perspective view of an optoelectronic device according to the present invention; FIG.

The optoelectronic device of the present invention has a structure as shown in FIG. This optoelectronic device 20 has an oscillation wavelength of 67
Emits 0nm laser light, for example, laser beam
Used as a light source for printers. This optoelectronic device 20
Each of these comprises a plate-shaped stem 21, which is the main component of the assembly, and a cap 22 hermetically fixed to the main surface of the stem 21. The stem 21 is several mm thick.
The heat sink 23 is made of a circular copper metal plate having a thickness of , and a copper heat sink 23 is fixed to the center of the main surface (upper surface) with solder. A semiconductor laser element 5 is fixed to the side surface of the heat sink 23 via a submount 1 made of copper. FIG. 1 is an enlarged view showing the fixed state of the semiconductor laser element 5. As shown in FIG. The semiconductor laser element 5 has a width of 400 μm, a length of 300 μm, and a height of 100 μm, for example.
m, and the laser beam 11 is emitted from output surfaces 12 at both ends of the resonator (not shown). The semiconductor laser element 5 is made of an AlGaInP visible light semiconductor laser, and is fixed to the chip mounting surface 25 of the submount 1 in a junction-down state via a solder 6 made of Pb-Sn. Further, the submount 1 is also fixed to the heat sink 23 by solder 26.

On the other hand, a light receiving element 27 is provided on the main surface of the stem 21 to receive the laser beam 11 emitted from the lower end of the semiconductor laser element 5 and monitor the optical output of the laser beam 11.
is fixed. This light receiving element 27 is fixed to an inclined surface 28 provided on the main surface of the stem 21 via a bonding material (not shown). This is to prevent the reflected light from the light receiving surface of the light receiving element 27 of the laser light 11 emitted from the semiconductor laser element 5 from entering the window of the cap, thereby preventing disturbance of the far field image. It is.

On the other hand, the stem 21 has three leads 2.
9 is fixed. One lead 29 is electrically and mechanically fixed to the back surface of the stem 21, and the other two leads 29 pass through the stem 21 and are electrically connected to the stem 21 through an insulator 30 such as glass. is insulated and fixed. The upper ends of the two leads 29 protruding from the main surface of the stem 21 are connected to respective electrodes of the semiconductor laser element 5 and the light receiving element 27 via wires 31, respectively.

Further, a metal cap 22 having a window 32 is hermetically fixed to the main surface of the stem 21 to seal the semiconductor laser element 5 and the heat sink 23. The window 32 is formed by airtightly closing a circular hole provided in the ceiling of the cap 22 with a transparent glass plate 33. Therefore, the laser light 11 emitted from the upper end of the semiconductor laser element 5 passes through the transparent glass plate 33 and is emitted outside the package formed by the stem 21 and the cap 22. A pair of V-shaped notches 34 and a rectangular notch 35 are provided on the outer circumferential portion of the stem 21 and are used for positioning during assembly. There is.

In such an optoelectronic device 20, which is one of the features of the present invention, a copper submount is used as the submount 1. In addition, when this copper submount 1 is formed by cutting a copper plate (copper foil) using conventional processing methods such as press processing, etching processing, dicing processing, etc., rounding (sagging) and protrusions may occur as described above. (
Since burrs, protrusions, etc. are undesirably generated in the cut portion, the copper submount 1 of the present invention is manufactured by using a composite processing method, that is, a two-step process of etching and dicing to remove copper from a copper plate (copper foil). Manufactures submount 1.

Next, the manufacturing of such a submount 1 will be explained, and the manufactured submount 1 will be explained.
We will clarify the shape of In manufacturing submount 1, as shown in Figure 2, a rectangular copper plate (copper foil) is first manufactured.
40 will be prepared. This copper plate (copper foil) 40 is selected to have a thickness of, for example, 0.2 mm. This copper plate (copper foil) 40 is then subjected to plating treatment. The plating process includes a Ni film 41 (see FIG. 3) with a thickness of several hundred nm applied to the entire front and back surfaces of the copper plate (copper foil) 40, and a copper plate (copper foil) 4.
An Au film 42 with a thickness of several tens of nanometers (see FIG. 3) is selectively provided to fix the semiconductor laser element 5 on the surface of the copper plate (copper foil) 40, and an Au film 42 with a thickness of several hundred nanometers is deposited on the back surface of the copper plate (copper foil) 40. The Au film 43 (see FIG. 3) has a thickness of several microns on the Au film 42 (see FIG. 3).
A Pb-Sn-In film 44 (see FIG. 3) having a thickness of m is sequentially applied. The Au film 42, as shown in FIG.
It is shaped like a dotted area. Moreover, in this Au film 42, the stepped front edge 7 of the submount 1
At point a, only a wider region corresponding to a resonator of a semiconductor laser (not shown) extends, and does not extend along the step leading edge 7a on both sides thereof. By providing the partial extension portion 42a in this manner, when the semiconductor laser element is fixed (chip bonding), extra solder is supplied at the step leading edge 7a, so that the solder is fed to the front of the semiconductor laser element 5. This prevents the laser beam 11 from protruding and becoming an obstacle to the laser beam 11. Further, the central part of the rear end of the Au film 42 becomes a concave pattern 42b, and the semiconductor laser element 5
When the semiconductor laser element 5 is fixed, the solder 6 is prevented from reaching the center part of the rear end of the semiconductor laser element 5. Care has been taken to avoid vignetting due to protruding parts.

Next, grooves 45 are formed in a grid pattern on the front and back surfaces of the copper plate (copper foil) 40 by etching. As shown in FIG. 3, this groove 45 has a width of about 0.25 mm and a depth of about 0.03 mm. Further, this groove 45 is partially thinned to form a stepped front edge 7a, which will be described later, of the submount. As shown in FIG. 3, the groove 45 in FIG. 2 has an etched edge that does not become rounded (sag) as in press processing or produce protrusions (burrs) as in press processing or dicing. ,
Moreover, the edge has a substantially right-angled cross section.

Next, the copper plate (copper foil) 40 is cut by dicing. Dicing is indicated by broken lines in Figure 2.
As shown by two parallel two-dot chain lines in FIG. 3, the groove 45 is formed approximately along the center thereof with a width of approximately 50 μm. The thin copper plate (copper foil) 40 is attached to a support plate (not shown) and then cut, similar to cutting of a wafer when forming a semiconductor integrated circuit element. In this cutting, the rotational speed of the cutting blade, cutting feed rate, etc. are selected so that the length of the protrusion (burr) generated on the cutting edge due to dicing is minimized to within 0.015 to 0.02 mm. . As a result, the tip of the burr (not shown) generated during dicing becomes shorter than the depth of the groove, so that the flat chip mounting surface 25 on the front side of the submount 1 surrounded by the etched groove 45 and the flat chip mounting surface 25 on the back side are It does not protrude above the support fixing surface 46, and does not cause any trouble in chip bonding and submount fixing in subsequent steps. The submount 1 manufactured by the dicing has a shape as shown in FIG. 4. In the submount 1, a step is generated around the submount 1, and a lower surface 47 is formed. This low surface 47 extends around the submount 1 with a width of about 0.1 mm excluding the stepped front edge 7a. This is because, as shown in FIG. 7, when the submount 1 on which the semiconductor laser element 5 is mounted is held by the bonding tool 48, the outermost periphery of the submount 1, that is, the edge of the lower surface 47, is held by the bonding tool 48. This is to prevent the edges 2a of the step from coming into contact with each other. The bonding tool 48 is partially cut out and provided with an escape portion 49 so that the bonding tool 48 does not come into contact with the semiconductor laser element 5 when the submount 1 is held. Therefore, the edge of the submount 1 that the bonding tool 48 contacts in the submount 1 is the edge area surrounded by the two-dot chain line shown in FIG.

Next, the manufacturing (assembly) of an optoelectronic device using such a copper submount 1 will be explained. As shown in FIGS. 5 and 6, the support surface 5 of the jig 52
After placing the submount 1 on the jig 52, push the corner of the submount 1 in the diagonal direction of the submount 1 using the positioning piece 54 whose tip is a V-shaped claw, and extend the submount 1 at right angles to the jig 52. It is positioned by pressing against the existing positioning protrusion 55. Note that, as shown in FIG. 6, a portion of the positioning protrusion 55 becomes a protruding reference surface 56 for positioning the front end 9 of the semiconductor laser element 5. Therefore, after holding the semiconductor laser element 5 at the lower end of the collet 57 by vacuum suction, the collet 57 is moved in the direction of the reference plane 56, and the front end 9 of the semiconductor laser element 5 is moved to the reference plane 56.
6. Further, the collet 57 is moved and adjusted relative to the jig 52 in the plane direction along the reference surface 56 to position it with respect to the submount 1. Thereafter, the collet 57 is lowered and the semiconductor laser element 5 is
is pressed against the submount 1, and the Pb-Sn-In film 44 of the submount 1 is temporarily melted by heating, thereby fixing the semiconductor laser element 5 to the submount 1. At this time, the fixed semiconductor laser element 5 is fixed to the submount 1 by the reference surface 56 within a mounting error range of 0 to 10 μm from the step leading edge 7a. Since the front end 9 of the semiconductor laser element 5 rests on the stepped front edge 7a having a substantially right-angled cross section, the heat at the front end 9 of the semiconductor laser element 5 is also quickly transferred to the submount 1. Effective heat dissipation becomes possible. Also, during this chip bonding, the chip mounting surface 2 of submount 1
Since the tip of a protrusion (burr) generated during manufacturing of the submount 1 does not protrude from the 5 side and the support fixing surface 46 side, the semiconductor laser element 5 is not fixed in an inclined manner. This also applies to the next case of fixing the submount 1.

Next, as shown in FIG. 7, the submount 1 on which the semiconductor laser element 5 is mounted is held by a bonding tool 48, pressed against a heat sink 23 serving as a support, and fixed by a solder 26. Ru. As shown in FIG. 8, the heat sink 23 is fixed to the main surface of the stem 21 to which the light receiving element 27 and leads 29 are attached. When fixing the semiconductor laser element 5, the bonding tool 48 is adjusted to move relative to the heat sink 23. This movement adjustment is performed by feedback of monitor information of the laser beam 11 emitted by the semiconductor laser element 5 whose drive is controlled when fixed. As a result, the semiconductor laser element 5 is fixed at a fixed position with respect to the stem 21 with high precision.

Next, the inner end of the lead 29 and the semiconductor laser element 5 and the light receiving element 27 are electrically connected by a wire 31. Further, a cap 22 to which a transparent glass plate 33 is attached is airtightly fixed to the main surface of the stem 21. As a result, the heat sink 23 , the inner end of the lead 29 , the light receiving element 27 , the wire 31 , the semiconductor laser element 5 fixed to the heat sink 23 , etc. arranged on the main surface of the stem 21 are hermetically sealed in the cap 22 . The optoelectronic device 20 as shown in FIG. 8 is completed.

According to this embodiment, the following effects can be obtained. (1) The optoelectronic device of the present invention uses copper as a submount. This copper submount is made by etching the front and back surfaces of a copper plate to form a lattice groove, and then dicing the bottom of the groove. Since it is obtained by cutting, there is no sag or burr on the edge of the step portion due to etching. Moreover, the burr caused by the dicing is generated at the bottom of the groove that is one step lower than the chip mounting surface or the support fixing surface, and therefore does not protrude above the chip mounting surface or the support fixing surface of the submount. Therefore, the fixed submount and semiconductor laser element are not tilted due to burrs and are normally fixed. As a result, in the optoelectronic device of the present invention, there is no variation in the emission direction of laser light due to the inclination of the submount or the semiconductor laser element, and the characteristics are stabilized.

(2) According to (1) above, in the optoelectronic device of the present invention, copper is used as the submount, and the semiconductor laser element is fixed on the copper submount.
Since the semiconductor laser element is fixed so that its leading edge overlaps the stepped front edge of the submount with no sag, the heat from the output surface that emits the laser beam is quickly transferred to the submount without sag through the solder. This results in effective heat dissipation and stable thermal characteristics.

(3) According to the above (1), in the optoelectronic device of the present invention, the submount is formed by etching and dicing during manufacturing. As a result, the length dimensions of the edge of the step formed by etching to which the front end of the semiconductor laser element is fixed and the edge of the submount formed by dicing are determined with high precision by the processing accuracy of the dicing device. Therefore, the fixing position accuracy of the semiconductor laser element based on the edge of the submount is high, and it is possible to fix the semiconductor laser element so that the front edge of the semiconductor laser element overlaps the stepped front edge of the submount without sag. Therefore, in the assembled optoelectronic device, the heat of the laser light emitting surface portion is also effectively radiated, resulting in the effect that the thermal characteristics are stabilized.

(4) Copper is used as a submount in the optoelectronic device of the present invention, but since copper has the second highest thermal conductivity after diamond, conventional methods using submounts of Si, AlN, SiC, etc. The effect is that the thermal characteristics are more stable compared to the optoelectronic device. therefore,
When the optoelectronic device of the present invention is used as a light source for a laser beam printer, it has good thermal characteristics even when drawing a long solid line, so the optical output does not gradually decrease while drawing a solid line. The last part of the drawn solid line can be drawn with the same density as the front part.

(5) Conventionally, nonmetals such as diamond, AlN, and SiC are used in optoelectronic devices with high heat dissipation properties, but these materials are expensive, and Cu is not as thermally conductive as diamond. Although the rate is not high, the AlN,S
A with significantly higher thermal conductivity and higher thermal resistance than iC
It is also sufficiently effective in dissipating heat from lGaInP semiconductor laser devices. Therefore, according to the present invention, it is possible to provide an inexpensive optoelectronic device with stable thermal characteristics.

(6) Although the optoelectronic device of the present invention uses a submount whose peripheral edge is lower and thinner, it can be held in the same manner as before using conventional bonding tools, so there is no need to change the assembly method. This effect can be obtained.

(7) According to the above (1) to (6), according to the present invention, a synergistic effect can be obtained in that an inexpensive optoelectronic device with stable temperature characteristics can be provided.

[0045] The invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Needless to say, for example,
In the above embodiment, Cu was used as the submount, but
Metals other than Cu, such as aluminum, molybdenum, tungsten, etc., or alloys thereof, can also be used to achieve high heat dissipation properties and reduced manufacturing costs.

Further, in the above embodiment, dicing was performed at the center of the groove, but the dicing position was shifted so that one end of the submount to be manufactured had a lower side longer than the other end. , the assembly may be facilitated. Furthermore, in the present invention, the same effect as in the above embodiment can be obtained even if the submount is manufactured by deforming the frame-shaped material using the deformed strip technique and then cutting the deformed groove portion with dicing. can get.

[0047] In the above explanation, the invention made by the present inventor will be mainly explained in relation to the application field of AlG, which is the background of the invention.
Although the case where it is applied to an optoelectronic device incorporating an aInP-based visible light semiconductor laser element and its manufacturing technology has been described, it is not limited thereto.
It can be applied to manufacturing techniques for GaAsP-based semiconductor lasers and GaAlAs-based semiconductor lasers. The present invention is applicable to at least optoelectronic devices that require high heat dissipation effects.

[0048]

Effects of the Invention A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows. Since the optoelectronic device of the present invention uses a copper submount, the heat dissipation property is
, and has better thermal characteristics than a submount made of AlN. In addition, since the submount is processed by etching and dicing the bottom of the etched groove, the edge is made into a right-angled cross section by etching, and the edge of the semiconductor laser element on the emission surface side is aligned and fixed to this edge, making it effective. A heat dissipation effect is possible. Furthermore, since the dimensional accuracy of the submount is achieved by dicing, the dimensional accuracy between the end of the submount and the etched edge is high, resulting in high assembly accuracy. In addition, the burr caused by the dicing does not affect the assembly because the dicing is performed at the bottom of the etched groove. Additionally, a reduction in the cost of optoelectronic devices can be achieved through the use of inexpensive copper submounts.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part showing a fixed state of a semiconductor laser element in an optoelectronic device according to an embodiment of the present invention.

FIG. 2 is a plan view of a portion of an etched copper plate for manufacturing a submount in an optoelectronic device of the invention;

FIG. 3 is a cross-sectional view of a portion of a copper plate used in manufacturing the optoelectronic device of the present invention.

FIG. 4 is a perspective view of a submount in the optoelectronic device of the invention.

FIG. 5 is a plan view showing the submount positioning state in manufacturing the optoelectronic device of the present invention.

FIG. 6 is a side view showing a fixed state of a semiconductor laser element in manufacturing the optoelectronic device of the present invention.

FIG. 7 is a cross-sectional view showing a state in which a submount having a semiconductor laser element is held in manufacturing the optoelectronic device of the present invention.

FIG. 8 is a perspective view with a part cut away of an optoelectronic device according to the invention.

FIG. 9 is a schematic diagram showing a state in which a semiconductor laser element is fixed to a surface having a rounded edge of a submount formed by press working.

FIG. 10 is a schematic diagram showing a state in which a semiconductor laser element is fixed to a surface having a protrusion on the edge of a submount formed by press working.

FIG. 11 is a schematic diagram showing a part of a submount formed by etching.

FIG. 12 is a schematic diagram showing the correlation between a submount with short protrusions formed by etching and the fixing position of a semiconductor laser element.

FIG. 13 is a schematic diagram showing the correlation between a submount with long protrusions formed by etching and a fixing position of a semiconductor laser element.

FIG. 14 is a schematic diagram showing a part of a submount formed by dicing.

[Explanation of symbols]

1... Submount, 2... Edge, 2a... Edge of step, 3... Roundness (sag), 4... Protrusion (burr), 5... Semiconductor laser element,
6... Solder, 7... Front edge, 7a... Step front edge, 9... Front end, 1
0...Gap, 11...Laser beam, 12...Emission surface, 13...Void, 14...Protrusion, 15...Swelling part, 20...Optoelectronic device, 21...Stem, 22...Cap, 23...Heat sink, 25...Chip mounting surface , 26... Solder, 27... Light receiving element, 28... Inclined surface, 29... Lead, 30... Insulator, 31
...Wire, 32...Window, 33...Glass plate, 34...V-shaped notch, 35...Rectangular notch, 40...Copper plate (copper foil), 41
...Ni film, 42...Au film, 42a...partial extension part, 42b
... Hollow pattern, 43... Au film, 44... Pb-Sn-I
n film, 45...groove, 46...support fixing surface, 47...low surface,
48... Bonding tool, 49... Relief portion, 52... Jig, 53... Support surface, 54... Positioning piece, 55... Positioning protrusion, 56... Reference surface, 57... Collet.

Claims (5)

[Claims] 1. An optoelectronic device comprising a support, a submount fixed to the main surface of the support, and a semiconductor laser element fixed to the main surface of the submount,
The submount is made of a metal plate, and the edges of the chip mounting surface and support fixing surface of the submount have no roundness or protrusion, and at least the edge where one end of the semiconductor laser element overlaps has a substantially right-angled cross section. An optoelectronic device characterized by: 2. The submount is made of a copper plate, and the peripheral edges of the front and back surfaces are formed one step lower and thinner, and the edge of the step has a substantially right-angled cross section. Optoelectronic device as described. 3. A method for manufacturing an optoelectronic device, comprising the steps of fixing a semiconductor laser element to the main surface of a submount, and fixing the submount to the main surface of a support, the method comprising: A process of plating a metal plate with high thermal conductivity, a process of forming grooves in a lattice shape by etching on the front and back surfaces of the metal plate, and cutting at the groove portions by dicing to form a layer around the front and back surfaces. forming a lowered submount. 4. A method for manufacturing an optoelectronic device, comprising the steps of fixing a semiconductor laser element to the main surface of a submount, and fixing the submount to the main surface of a support body, the method comprising: A process of plating a metal plate with high thermal conductivity, a process of forming grooves in a lattice shape by etching on the front and back surfaces of the metal plate, and cutting at the groove portions by dicing to form a layer around the front and back surfaces. forming a lowered submount, and in the etching, the etched edges are made to have a substantially right-angled cross section, and the depth of the etched groove is deeper than the length of the protrusion generated by dicing. A method for manufacturing an optoelectronic device according to claim 3, characterized in that: 5. A method for manufacturing an optoelectronic device, comprising the steps of fixing a semiconductor laser element to the main surface of a submount, and fixing the submount to the main surface of a support, A process of plating a metal plate with high thermal conductivity, a process of forming grooves in a lattice shape by etching on the front and back surfaces of the metal plate, and cutting at the groove portions by dicing to form a layer around the front and back surfaces. forming a lowered submount, and positioning the semiconductor laser element with reference to the cut surface of the submount by dicing so that the emission surface of the semiconductor laser element slightly protrudes from the step edge formed by the groove. A method for manufacturing an optoelectronic device, comprising the step of fixing.