KR102266664B1 - Stem unit and semiconductor device raser diode package - Google Patents

Abstract

A stem unit and semiconductor laser diode package are disclosed. A stem unit comprising a clad having a plurality of class holes and a heat sink bonded to an upper surface of the clad and to which an optical element is fixed, wherein the clad is made of copper (Cu), and an upper layer to which the heat sink is fixed to the upper surface , a lower layer formed of copper (Cu), and an intermediate layer positioned between the lower layer and the upper layer and formed of iron (Fe).

Description

STEM UNIT AND SEMICONDUCTOR DEVICE RASER DIODE PACKAGE

The present invention relates to a stem unit and a semiconductor laser diode package, and more particularly, to a stem unit in which a laser diode is mounted and a semiconductor laser diode package in which a laser beam is oscillated through a laser diode mounted in the stem unit.

In general, a laser beam oscillated from a laser diode has a narrow frequency width and high directivity, and thus has been applied to various fields such as optical communication, multiplex communication, and space communication.

In modern times, as the demand for telecommunication services increases, optical disks, which are one of the main application fields of laser diodes along with optical communication networks, are compact disk players and compact disk reading/writing systems. A laser diode capable of low current oscillation and long-term operation is required in the device.

Such a laser diode is generally composed of a semiconductor laser diode package and fixed to a PCB or the like. The semiconductor laser diode package consists of an optical device, a stem unit that fixes the optical device, a terminal pin that electrically connects the PCB and the optical device, and a ground pin.

Republic of Korea Patent No. 10-1121065 discloses, "A stem unit on which an optical element is mounted, a base made of a metal plate, in order to implement various shapes of the base member and the heat sink by separately manufacturing the base member and the heat sink forming the stem. a heat sink member manufactured separately from the base member and joined to the upper surface of the base member and to which the optical element is fixed; and a bonding member bonding the base member and the heat sink to each other, wherein the heat sink comprises: A mounting portion on which an optical device is mounted and an extension portion extending from both sides of the mounting portion and bent to surround the optical device, wherein a material having a lower melting point than that of the base member and the heat sink is used for the bonding member, and a brazing method is performed on the base. A stem unit for bonding between a member and a heat sink” is disclosed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stem unit and a semiconductor laser diode package that can be manufactured at low cost while improving thermal conductivity and hermetic bonding properties.

Another problem to be solved by the present invention is to provide a stem unit and a semiconductor laser diode package having improved stem bonding strength.

In order to achieve the above object, a stem unit according to the present invention includes a clad having a plurality of class holes, a heat sink bonded to an upper surface of the clad and fixed with an optical element, The clad includes: an upper layer formed of copper (Cu) and having the heat sink fixed to an upper surface thereof; a lower layer formed of copper (Cu); and an intermediate layer disposed between the lower layer and the upper layer and formed of iron (Fe).

The clad may further include a ring layer positioned on the upper layer and formed in a ring shape to surround the plurality of class holes and the heat sink. The ring layer may be formed of iron (Fe).

The heat sink or the ring layer may be joined to the upper layer by a brazing method using an alloy of silver (Ag) and copper (Cu).

In a region positioned inside the ring layer among the upper surface of the upper layer, a region to which the heat sink is attached may occupy half or more of a cross-sectional area.

The heat sink may be formed of copper (Cu).

In order to achieve the other object to be solved, a semiconductor laser diode package according to the present invention includes a stem unit according to the present invention; one or more optical elements fixed to the stem unit; one or more terminal pins attached to one of the plurality of class holes of the stem unit; and a ground pin attached to the other one of the plurality of class holes of the stem unit.

According to the stem unit and semiconductor laser diode package according to the present invention, the clad is composed of an upper layer formed of copper (Cu), an intermediate layer formed of iron (Fe), and a lower layer formed of copper. The heat dissipation is excellent by transferring the heat received through the lower layer with high thermal conductivity to the outside, and the volume change of the upper and lower layers due to heat is offset by the middle layer with a low thermal expansion coefficient, thereby improving hermetic bonding. Since the middle layer is formed of low-cost iron, it can be manufactured at low cost, and by providing the golden ratio of the upper layer, the middle layer and the lower layer, the bonding strength of the stem is improved.

1 is an exploded perspective view of a preferred embodiment of a semiconductor laser diode package according to the present invention.
2 is a perspective view of a preferred embodiment of a semiconductor laser diode package according to the present invention.
3 is a vertical cross-sectional view of a preferred embodiment of a semiconductor laser diode package according to the present invention.
4 is a horizontal cross-sectional view of a preferred embodiment of the semiconductor laser diode package according to the present invention.
5 is a vertical cross-sectional view of Comparative Example 1.
6 is a vertical cross-sectional view of Comparative Example 2.
7 is a vertical cross-sectional view of Comparative Example 3.

Hereinafter, a stem unit and a semiconductor laser diode package according to the present invention will be described in detail with reference to the accompanying drawings. At this time, the configuration and operation of the present invention shown in the drawings and described by it is described as at least one embodiment, and the technical idea of the present invention and its core configuration and operation are not limited thereby.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or custom of a person skilled in the art or the advent of new technology. In addition, in specific cases, there are also terms arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, it is intended to clarify that the terms used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than a simple term.

1 is an exploded perspective view of a preferred embodiment of a semiconductor laser diode package according to the present invention, FIG. 2 is a perspective view of a preferred embodiment of a semiconductor laser diode package according to the present invention, and FIG. 3 is a semiconductor laser according to the present invention It is a vertical cross-sectional view of a preferred embodiment of the diode package, and FIG. 4 is a horizontal cross-sectional view of a preferred embodiment of the semiconductor laser diode package according to the present invention.

1 to 4 , the semiconductor laser diode package 10 according to the present invention may include an optical device 20 , a stem unit 30 , a terminal pin 300 , and a ground pin 400 .

The optical element 20 is a light source for irradiating a laser beam. The optical element 20 may irradiate laser beams having the same phase in the same direction. The optical device 20 may be implemented as a laser diode. The semiconductor laser diode package 10 may include one or more optical devices 20 .

The stem unit 30 is to which the optical device 20 is attached thereto, and emits high heat generated during operation of the attached optical device 20 . The stem unit 30 may include a clad 100 in which a plurality of class holes 101 and 103 are formed, and a heat sink 200 bonded to the upper surface of the clad 100 and to which the optical element 20 is fixed. can

The clad 100 is made of metal, and the heat sink 200 , the terminal pin 300 , and the ground pin 400 are coupled thereto. The clad 100 may be implemented in a three-dimensional shape such as a cylindrical shape, a semi-cylindrical shape, and a polygonal cylindrical shape, and may be implemented as a plate material such as a plate shape, an oval shape, and a complex shape.

In the clad 100, one or more class holes 101 and 103 to which the terminal pins 300 are coupled may be formed by penetrating up and down, and a photodiode for sensing the laser beam irradiated by the optical device 20 is mounted. A seating groove 105 may be formed. A photodiode may be mounted in the seating groove 105 .

The clad 100 may include a lower layer 110 , an intermediate layer 120 , an upper layer 130 , and a ring layer 140 . The lower layer 110 is located under the intermediate layer 120 and may be formed of copper (Cu). The intermediate layer 120 is positioned between the lower layer 110 and the upper layer 130 and may be formed of iron (Fe). The upper layer 130 is formed on the intermediate layer 120 and may be made of copper (Cu). A heat sink 200 may be fixed to the upper surface of the upper layer 130 , and a seating groove 105 may be formed. In the present invention, since the upper layer 130 is formed of copper having high thermal conductivity, heat from the optical device 20 is transferred through the heat sink 200 and the heat transferred through the lower layer 110 formed of copper is transferred to the outside. It has excellent thermal conductivity and heat dissipation by transferring it, and since the intermediate layer 120 is formed of iron with a low thermal expansion coefficient, the volume change of the upper layer 130 and the lower layer 110 due to heat is offset to improve the hermetic bonding, and the intermediate layer ( 120) has the effect that it can be manufactured at a low cost by being formed of low-cost iron.

Preferably, the lower layer 110 , the intermediate layer 120 , and the upper layer 130 may have a thickness ratio of 1:2:1. Accordingly, the clad 100 has an optimal effect of reducing the production cost while maintaining excellent heat dissipation and hermetic bonding properties.

The ring layer 140 is positioned on the upper layer 130 , and may be formed in a ring shape to surround the plurality of class holes 101 and 103 , the seating grooves 105 , and the heat sink 200 . An alloy of silver (Ag) and copper (Cu) may be used for the ring layer 140 to be joined to the upper layer 130 by a brazing method, and may be formed integrally with the upper layer 130 . The ring layer 140 may be formed of iron (Fe). Accordingly, the ring layer 140 is formed of iron having a low thermal expansion coefficient, thereby offsetting the volume change of the upper layer 130 formed of copper (Cu) having a high thermal expansion coefficient, thereby improving the hermetic bonding property.

The terminal pin 300 is a means for supplying power to the optical device 20 and the photodiode, and may be fixed to protrude upward and downward of the clad 100 through the class hole 101 formed in the clad 100 . . At this time, between the terminal pin 300 and the clad 100 may be insulated by the insulator 190 . Accordingly, one side of the terminal pin 300 may be connected to the optical device 20 and the photodiode and the wire 21 , and the other side may be connected to the outside. Here, a substrate such as a PCB may be positioned outside the above, and the other end of the terminal pin 300 may be connected to the substrate. In addition, the terminal pin 310 may penetrate through the class hole 103 and be fixed to protrude upward and downward of the clad 100 .

The ground pin 400 may be bonded to the lower surface of the clad 100 to be physically and electrically connected. At this time, the ground pin 400 may be fixed by simple welding, or may be fixed to the clad 100 through the welding material 401 . The ground pin 400 may ground the stem unit 30 .

The heat sink 200 has a function and function of directly dissipating the high heat generated by the optical device 20 on which the optical device 20 is mounted, and may be manufactured integrally with the clad 100 or manufactured separately. . In addition, the heat sink 200 may be manufactured to protrude from the upper surface of the clad 100 . In some embodiments, the heat sink 200 may be joined to the upper layer 130 by a brazing method using an alloy of silver (Ag) and copper (Cu).

Preferably, the heat sink 200 may be manufactured such that a region to which the heat sink 200 is attached in a region located inside the ring layer 140 among the upper surface of the upper layer 130 occupies more than half of the cross-sectional area. Accordingly, in the present invention, thermal conductivity may be improved.

Preferably, the heat sink 200 is attached to occupy an area including the center of the clad 30 , and a straight line passing through the midpoint of the class hole 101 and the midpoint of the class hole 103 and the center of the clad 30 . The distance between them may be smaller than half the length of the inner radius of the ring layer 140 . Accordingly, the cross-sectional area of the heat sink 200 attached to the clad 30 may be increased, and the heat dissipation property of the clad 30 may be improved.

Preferably, the heat sink 200 may be formed of copper (Cu). Accordingly, in the present invention, the heat emitted by the optical device 20 is transferred to the clad 100 through copper having excellent thermal conductivity, so that it has excellent thermal conductivity and heat dissipation, and the heat sink 200 and the upper layer 130. Since it is made of such a material, thermal conductivity and bonding properties between the clad 100 and the heat sink 200 are more excellent.

FIG. 5 is a vertical cross-sectional view of Comparative Example 1, FIG. 6 is a vertical cross-sectional view of Comparative Example 2, and FIG. 7 is a vertical cross-sectional view of Comparative Example 3. As shown in FIG.

5 to 7 , an experiment was conducted to compare the characteristics of Examples and Comparative Examples of the present invention, and the results are shown in Table 1 below. In Examples and Comparative Examples, the thicknesses of the clad and the heat sink were the same, the longest cross-sectional area of the clad was the same, and, except for Comparative Example 3, the clad and the heat sink used an alloy of silver (Ag) and copper (Cu). Thus, it was joined by a brazing method. However, the cross-sectional area of the heat sink of Example 1 was made to occupy more than half of the inner region of the ring layer, and the cross-sectional area of the heat sink of Example 2 was made smaller than half of the inner region of the ring layer, and the heat sinks of Comparative Examples 1 to 3 The cross-sectional area of was prepared to be the same as that of Example 2. In addition, the structural shapes of Comparative Examples 1 to 3 are the same as in FIGS. 5 to 7 , respectively.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 heatsink material Copper (Cu) Copper (Cu) Copper (Cu) Copper (Cu) Copper (Cu) clad material Copper (Cu)
iron (Fe)
Copper (Cu) Copper (Cu)
iron (Fe)
Copper (Cu) iron (Fe) Copper (Cu) Copper (Cu) join AgCu Brazing AgCu Brazing AgCu Brazing AgCu Brazing single manufacturing ring layer material iron (Fe) iron (Fe) iron (Fe) iron (Fe) iron (Fe) ring layer bonding AgCu Brazing AgCu Brazing AgCu Brazing AgCu Brazing AgCu Brazing heat release 5 4 2 4 5 hermetic bonding 4 4 4 2 2 cost 4 4 4 2 One Comprehensive evaluation 4.33 4 3.33 2.66 2.66

(5: very good, 4: good, 3: average, 2: bad, 1: very bad)

As can be seen from the experimental results of Table 1, it can be seen that Examples 1 and 2 according to the present invention are superior in the comprehensive evaluation than the conventional Comparative Examples 1 to 3 because the heat dissipation property, airtight bonding, and cost are low. In particular, it can be seen that Example 1 exhibits the same heat dissipation property as Comparative Example 3 made of integrated copper.

Although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific preferred embodiments described above, and in the technical field to which the present invention belongs, without departing from the gist of the present invention as claimed in the claims Any person skilled in the art can make various modifications, of course, and such modifications are within the scope of the claims.

Semiconductor Laser Diode Package (10) Optical Device (20)
Stem Unit(30) Clad(100)
Heat sink (200) terminal pin (300)
ground pin (400)

Claims (7)

A stem unit comprising a clad having a plurality of class holes, and a heat sink bonded to an upper surface of the clad and to which an optical element is fixed,
The clad is
an upper layer formed of copper (Cu) and having the heat sink fixed thereon;
a lower layer formed of copper (Cu);
an intermediate layer disposed between the lower layer and the upper layer and formed of iron (Fe); and
It is positioned on the upper layer and is formed in a ring shape and includes a ring layer surrounding the plurality of class holes and the heat sink,
and a region to which the heat sink is attached in a region located inside the ring layer among the upper surface of the upper layer occupies more than half of the cross-sectional area, and the plurality of class holes are located in the remaining region. delete The method of claim 1,
The ring layer is
Stem unit, characterized in that formed of iron (Fe). The method of claim 1,
The heat sink or the ring layer,
A stem unit characterized in that an alloy of silver (Ag) and copper (Cu) is used and joined to the upper layer by a brazing method. delete According to claim 1,
The heat sink is a stem unit, characterized in that formed of copper (Cu). A stem unit according to any one of claims 1, 3, 4, and 6;
one or more optical elements fixed to the stem unit;
one or more terminal pins attached to one of the plurality of class holes of the stem unit; and
and a ground pin attached to the other one of the plurality of class holes of the stem unit.

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