JP3783571B2 - Semiconductor laser module and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor laser module that is a coupler of a semiconductor laser element and an optical fiber used in an optical communication device or the like.
[0002]
[Prior art]
In recent years, a method for multiplexing and transmitting wavelengths (WDM) has been developed and put into practical use. In this method, since light of a plurality of wavelengths exists in one optical fiber, it is necessary to set the wavelength of one light source to ± 0.1 nm.
[0003]
A semiconductor laser element is used as a laser light source for such optical communication, and the semiconductor laser element and a lens are integrally accommodated in a package to constitute a semiconductor laser module, and the semiconductor laser module is coupled to an optical fiber. It is made to do. In such a semiconductor laser module, since the wavelength of the semiconductor laser changes when the ambient temperature changes, an electronic cooling element (hereinafter referred to as a Peltier element) is provided in the structure of the semiconductor laser module coupled to the optical fiber, The temperature of the semiconductor laser element is controlled.
[0004]
Such a semiconductor laser module 70 is, for example, FIG. As shown in FIG. 1, a package main body 71 constituting a butterfly type or DIP type package having lead wires provided with hermetic seals on a pair of side walls (not shown) is provided, and light is extracted from the other side wall of the package main body 71. A window 71a is provided. An airtight cover 71b is attached to the upper portion of the package body 71. Here, a Peltier element 72 composed of a plurality of P-type semiconductor compound elements and N-type semiconductor compound elements is sandwiched between a pair of insulating plates 72a, 72b in the package body 71, and a plurality of P's are formed by electrodes (not shown). Type element and a plurality of N type elements are electrically connected in series in the order of P, N, P, N, and lead wires (not shown) are connected to the electrodes joining the P type element and the N type element at the end. Configured.
[0005]
The insulating plates 72a and 72b are made of alumina or the like, and a metal conductor pattern (electrode pattern) that also serves as an electrode and fixing of the Peltier element 72 is formed as a thin film or a thick film thereon. A base plate 73 on which a semiconductor laser element 74, a lens 78, a light receiving element 77, and the like are mounted is fixed to the insulating plate 72a side, and the insulating plate 72b side is fixed to the inner bottom of the package body 71. The semiconductor laser element 74 is mounted on a heat sink 75. The heat sink 75 radiates heat from the semiconductor laser element 74 and uses a material (for example, diamond, SiC, silicon, etc.) having substantially the same expansion coefficient as the semiconductor laser element 74. Therefore, failure due to thermal stress is prevented.
[0006]
The heat sink 75 is mounted on a header 76, and the header 76 has terminals for electrodes of the semiconductor laser element 74. A light receiving element 77 for monitoring is provided at the rear of the header 76. The light receiving element 77 monitors a change in light output due to a temperature change or the like of the semiconductor laser element 74 so that the light output is always constant. Feedback is applied to the drive circuit. The lens 78 is fixed by a lens holder 79.
[0007]
The lens holder 79 is fixed to the base 73 with a YAG laser after adjusting the optical axis so that the laser beam emitted from the semiconductor laser element 74 and spread is converted into parallel light by the lens 78. This is because YAG laser welding with high fixation stability is used because the axial deviation sensitivity of the semiconductor laser element 74 and the lens 78 after optical adjustment is as severe as 1 μm or less. Thus, the laser light emitted from the semiconductor laser element 74 is converted into parallel light by the lens 78, and this parallel light passes through the light extraction window 71a.
[0008]
A sleeve 82 is disposed in front of the lens 78, and a ferrule is placed on the sleeve 82. 83 The lens 81 is fixed via the. Here, after adjusting the optical axis so that the laser light emitted from the semiconductor laser element 74 and passing through the light extraction window 71a is efficiently incident on the optical fiber 84 by the lens 81, YAG laser welding is performed at the A and B portions of the sleeve 82. It is fixed. Thereby, the light emitted from the semiconductor laser element 74 is efficiently coupled to the optical fiber 84 by the lenses 78 and 81. The temperature of such a semiconductor laser module is stable because the temperature of the semiconductor laser element 74 is constantly controlled by the Peltier element 72 and the temperature rise due to heat generation of the semiconductor laser element 74 is reduced. The heat generated by the semiconductor laser element 74 and the Peltier element 72 is radiated to the outside by a heat sink (not shown) attached to the package body 71.
[0009]
[Problems to be solved by the invention]
The semiconductor laser module having the above configuration has a problem that since the electronic cooling element (for example, a Peltier element) 72 is mounted, the height direction is particularly limited, and it is difficult to reduce the size. In view of this, a semiconductor laser module having a small size and an excellent cooling capability has been proposed in, for example, Japanese Patent Application Laid-Open No. 5-226679. In the semiconductor laser module proposed in Japanese Patent Application Laid-Open No. 5-226779, the package body bottom lid and the lower substrate have a common structure, thereby enabling a reduction in size.
[0010]
However, in the semiconductor laser module proposed in the above-mentioned Japanese Patent Application Laid-Open No. 5-22679, a method is adopted in which a Peltier element is joined to the bottom lid of the package body and then the package body is joined to the bottom lid. Yes.
After the Peltier element is joined to the bottom lid of the package body, the package body is joined to the bottom lid. The junction between the bottom lid and the package body is based on the melting point of the joining material joining the bottom lid and the Peltier element. It is necessary to use a bonding material having a melting point higher than that of the bonding material for bonding the bottom cover and the Peltier element. Therefore, the bonding force between the bottom lid and the package body is low, resulting in a problem of lack of reliability.
[0011]
Accordingly, the present invention has been made to solve the above-described problems, and provides a semiconductor laser module capable of improving the reliability of the joint portion between the package body and the bottom lid of the package body and reducing the size. It is intended to do.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor laser module of the present invention includes a first electrode formed on a substrate thermally coupled to a semiconductor laser element, and a second electrode formed on a bottom lid that seals the package body. A plurality of Peltier elements connected between the first and second electrodes, a first bonding material for bonding the package body and the bottom lid, and one end of the first electrode and the plurality of Peltier elements A second bonding material for bonding the second electrode, and the second electrode and the other end of the plurality of Peltier elements Through the conductive layer A first bonding material having a higher melting point than the second bonding material, and the second bonding material has a higher melting point than the third bonding material, or a third bonding material. The bonding material has the same melting point as the material.
[0013]
Thus, the first bonding material uses a bonding material having a higher melting point than the second bonding material, and the second bonding material has a higher melting point than the third bonding material or a bonding material having the same melting point as the third bonding material. When the package body and the bottom lid are joined by the first joining material, the other end of the plurality of Peltier elements joined to the first electrode by the second joining material is joined by the third joining material. Even when the two electrodes are joined, the first joining material is not melted when the third joining material is melted, so that a joining portion having a high joining strength is formed and a highly reliable joining portion is obtained. become. If a conductive layer is provided between the second electrode and the other end of the plurality of Peltier elements, the thickness of the second electrode can be reduced, so the second electrode can be formed as a thin film. It becomes possible, and can be formed of a refractory metal having a high resistance.
[0014]
If a package body in which the bottom wall on which the second electrode is formed is integrally formed is used, the bonding process between the package body and the bottom lid can be omitted, so that the bonding process can be reduced. The semiconductor laser module can be easily manufactured at a low cost. In this case, if the second electrode formed on the bottom wall is made of a refractory metal, the second electrode will not be melted even if the package body and the bottom lid are integrally formed. When the resistance value of the refractory metal is high and the conductivity is low, the refractory metal may be provided with a conductive layer having good conductivity.
[0015]
The method for manufacturing a semiconductor laser module according to the present invention includes a first bonding step of bonding a bottom lid for sealing the package body on which the second electrode is formed to the lower end of the package body with a first bonding material; A second bonding step of bonding one end of a plurality of Peltier elements on a substrate on which electrodes are formed with a second bonding material having a melting point lower than that of the first bonding material; and conducting to the other end of the plurality of Peltier elements Bonding layers with a second bonding material And the thermoelectric module A third joining step, and For thermoelectric module A fourth bonding step of bonding the bonded conductive layer to the second electrode with a third bonding material having a melting point lower than that of the second bonding material or a third bonding material having a melting point equal to that of the second bonding material.
[0016]
As described above, when the first joining step, the second joining step, the third joining step, and the fourth joining step are provided, the package body and the bottom cover are joined by the first joining material in the first joining step. . At this time, even if the melting point of the first bonding material is high, the other bonding portions are not affected, so that the package body and the bottom lid are firmly bonded. Alternatively, if the second joining process and the third joining process are performed at the same time, a single melting process is sufficient. That is, the remelting process itself of the second bonding material can be eliminated. Next, in the second bonding step, one end of the plurality of Peltier elements is bonded to the substrate on which the first electrode is formed by the second bonding material having a melting point lower than that of the first bonding material.
[0017]
Thereafter, in the third bonding step, the conductive layer is bonded to the other end of the plurality of Peltier elements by the second bonding material. The second bonding material is the same bonding material as the second bonding material in the second bonding step. Therefore, it hardly melts. Next, in the fourth joining step, the other ends of the plurality of Peltier elements are joined to the second electrode by the third joining material. Since the third joining material has a lower melting point than the second joining material, The first bonding material and the second bonding material do not melt. As a result, a joint with high joint strength is formed, and a highly reliable joint can be obtained.
[0018]
In addition, when the third bonding material has the same melting point as that of the second bonding material, there is a demerit that the second bonding material is remelted in the fourth bonding process. There is a merit that the thermal stress is small.
At this time, the melting points of the second bonding material used in the second bonding step, the second bonding material used in the third bonding step, and the third bonding material used in the fourth bonding step may be the same. In this case, since all the bonding materials have the same melting point, there is a demerit of remelting, but since all the bonding materials solidify at the same temperature, there is an advantage that there is little thermal stress remaining in the module.
[0019]
The first electrode is patterned on the substrate with a thin film or a thick film, and the second electrode is formed on the bottom cover with a thin film (in this case, for example, firing by the Mo-Mn method or W method) or a thick film (in this case If the pattern is formed by, for example, plating, each electrode can be easily formed. The first bonding material is preferably silver wax or glass, the second bonding material is preferably tin-antimony alloy solder, and the third bonding material is tin-lead eutectic solder or tin-antimony alloy solder. It is preferable that
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, the first embodiment, the second embodiment, and the third embodiment of the present invention will be described. Example In order, FIG. FIG. Based on
[0021]
1. First embodiment
First, a first embodiment will be described with reference to FIGS. 1A is a perspective view schematically showing the package body of the first embodiment, and FIG. 1B is a perspective view schematically showing the bottom cover of the first embodiment. FIG. 2A is a cross-sectional view schematically showing the main part of the thermoelectric element module of the first embodiment, and FIG. 2B is a diagram showing the thermoelectric element module joined in the package body of FIG. It is sectional drawing which shows the principal part of a state typically.
[0022]
As shown in FIGS. 1 to 2, the semiconductor laser module 10 according to the first embodiment includes a box-shaped package body 11 having an open top and bottom surface, a bottom lid 12 of the package body 11, and a package body 11. The Peltier element module 10a is arranged. A heat sink (not shown) is provided on the lower surface of the bottom cover 12. The package body 11 is made of a Fernico alloy of 54% Fe, 29% Ni, 17% Co (trade name: Kovar) or an alloy of 58% Fe, 42% Ni (trade name: 42 alloy). A pair of side walls of the package body 11 are provided with insulating materials 11a and 11a made of ceramic provided with lead wires 11b with hermetic seals to form a so-called butterfly type package. Further, a light extraction window 11c is provided on the other side wall.
[0023]
The bottom cover 12 is made of a ceramic material having a thermal expansion coefficient substantially equal to that of the package body 11, such as alumina (Al ₂ O _Three ), Alumina nitride (AlN), silicon carbide (SiC), or the like, or CuW, the surface of a metal material such as Kovar described above is insulated, and an electrode pattern (second Electrodes) 12a, 12a, 12a... Are provided in large numbers (for example, 32). These electrode patterns 12a, 12a, 12a,... Are formed, for example, by performing copper (Cu) plating on the bottom cover 12 and then removing unnecessary portions by etching. In addition, there is a method in which the metallized layer is formed by firing using the Mo—Mn method or the W method. In this case, even if the pattern is formed in the state of the green sheet before firing, which is easy to process the ceramic material, the electrode pattern is not dissolved in the firing step, so that it can cope with complicated shapes other than the flat plate.
[0024]
The thermoelectric element (Peltier element) module 10a includes a substrate (first substrate) 13, an electrode pattern (first electrode) 13a formed on the substrate 13, a P-type semiconductor compound element 14a, and an N-type semiconductor compound element. 14 b and a conductive pattern (conductive layer) 15. The substrate 13 is made of a ceramic material similar to that of the bottom cover 12, such as alumina (Al ₂ O _Three ), Alumina nitride (AlN), silicon carbide (SiC), and the like, and an electrode pattern 13a is formed on the substrate 13 by copper (Cu) plating and etching.
[0025]
Both ends of the P-type semiconductor compound element 14a and the N-type semiconductor compound element 14b are subjected to nickel plating, and solder plating is applied on the nickel plating. The P-type semiconductor compound elements 14a and the N-type semiconductor compound elements 14b are alternately arranged, and are electrically connected in series in the order of P, N, P, and N by the electrode pattern 13a and the conductive pattern 15. Note that the ends of the P-type semiconductor compound element 14a and the N-type semiconductor compound element 14b, the electrode pattern 13a, and the conductive pattern 15 are made of tin (Sn) -antimony (Sb) solder having a melting point (Tm) of about 240 ° C. Soldered by the second bonding materials 16 and 17.
[0026]
Next, a method for manufacturing the semiconductor laser module 10 of the first embodiment configured as described above will be described.
(1) First joining process
First, a box-shaped package body 11 having an open top and bottom surface and a bottom lid 12 having a large number (for example, 32) of electrode patterns (second electrodes) 12a, 12a, 12a,. The bottom lid 12 is fixed to the lower end portion of the package body 11 with a first bonding material such as silver wax or glass.
[0027]
(2) Second joining process
On the other hand, a substrate 13 having a large number of electrode patterns 13a formed on the surface thereof, a P-type semiconductor compound element 14a and an N-type semiconductor compound element 14b which are plated with nickel on both ends and solder-plated on the nickel plating, Conductive patterns 15 are prepared. Then, P-type semiconductor compound elements 14a and N-type semiconductor compound elements 14b are alternately arranged on a large number of electrode patterns 13a formed on the substrate 13, and P-type semiconductor compound elements 14a and N-type semiconductor compound elements 14b are formed. The melting point (Tm) of the electrode pattern 13a and one end of the P-type semiconductor compound element 14a and the N-type semiconductor compound element 14b is about 240 ° C. so that they are electrically connected in series via the electrode pattern 13a. It solders with the 2nd joining material 16 which consists of a certain Sn-Sb solder.
[0028]
(3) Third joining step
Subsequently, the P-type semiconductor compound element 14a and the N-type semiconductor compound element 14a and the N-type semiconductor compound element 14b are electrically connected in series with each other through the conductive pattern 15. The conductive pattern 15 is disposed on the other end of the element 14b, and the conductive pattern 15 and the other end of the P-type semiconductor compound element 14a and the N-type semiconductor compound element 14b are connected to a second bonding material, for example, a melting point (Tm ) Is soldered with a second bonding material 17 made of Sn—Sb solder having a temperature of about 240 ° C. to produce a thermoelectric element (Peltier element) module 10a. In addition, you may perform this 2nd joining process and 3rd joining process simultaneously, ie, one joining process.
[0029]
(4) Fourth joining step
Next, a third bonding material such as a melting point is formed on a number of electrode patterns 12a, 12a, 12a... Formed on the bottom lid 12 of the package body 11 to which the bottom lid 12 is fixed by silver brazing or glass sealing. Solder cream 18 made of tin (Sn) -lead (Pb) eutectic solder having a Tm of about 182 ° C. is applied. Thereafter, the thermoelectric element (Peltier element) module 10a produced as described above is turned upside down in the package body 11 so that the substrate 13 faces upward, and the electrode pattern 12a of the bottom cover 12 and the thermoelectric element ( The Peltier element) is arranged from above so that the conductive pattern 15 of the module 10a matches. Next, after heating to a temperature of about 182 ° C., the thermoelectric element (Peltier element) module 10 a is cooled while being pressed against the bottom lid 12, and the electrode pattern 12 a and the conductive pattern 15 are joined with the solder cream 18.
[0030]
Next, Similar to FIG. On the substrate 13, a header on which a semiconductor laser element is mounted via a heat sink (not shown), a lens holder on which a lens is fixed, and a base plate on which a light receiving element is mounted are fixed by soldering, and an upper lid is attached to the upper end of the package body 11 Are hermetically sealed to form a semiconductor laser module. A heat sink (not shown) is provided on the lower surface of the bottom lid 12 so that heat generated by the semiconductor laser element and the Peltier element is radiated to the outside through the heat sink.
[0031]
As described above, in the first embodiment, the package body 11 and the bottom cover 12 are joined by the first joining material in the first joining step. At this time, even if the melting point of the first bonding material is high, the other bonding portions are not affected, so that the package body 11 and the bottom lid 12 are firmly bonded. Next, one end of the plurality of Peltier elements 14a and 14b is bonded to the substrate 13 on which the first electrode 13a is formed in the second bonding step by the second bonding material 16 having a melting point lower than that of the first bonding material.
[0032]
Thereafter, in the third bonding step, the conductive pattern (conductive layer) 15 is bonded to the other end of the plurality of Peltier elements 14a and 14b by the second bonding material 17, and the second bonding material 17 is bonded to the second bonding step. Since it is the same bonding material as the second bonding material 16 in FIG. Next, in the fourth bonding step, the other ends of the plurality of Peltier elements 14a and 14b are bonded to the electrode pattern (second electrode) 12a by the third bonding material 18, and the third bonding material 18 is the second bonding material. Since the melting point is lower than 16 and 17, the first bonding material and the second bonding material 16 and 17 are not melted during the bonding. As a result, the amount of brittle intermetallic compounds such as Ni—Sn and Ni—Au generated at the time of remelting is reduced, so that a joint with high joint strength is formed, and a highly reliable joint can be obtained. .
[0033]
Further, when the third bonding material 18 has a melting point equivalent to that of the second bonding materials 16 and 17, there is a demerit that the second bonding materials 16 and 17 are remelted in the fourth bonding step, but they are simultaneously melted and simultaneously solidified. Therefore, there is an advantage that the thermal stress generated during solidification is particularly small. This merit is particularly great in terms of long-term reliability. Accordingly, the melting points of the second bonding materials 16 and 17 and the third bonding material 18 can be selected depending on the application.
[0044]
2 . Second Example
Next, Second Example FIG. and FIG. Based on In addition, FIG. Is a book Second It is a perspective view which shows the package main body of an Example typically. Also, FIG. (A) is a book Second It is a cross-sectional view schematically showing the main part of the thermoelectric element module of the example, FIG. (B) shows this thermoelectric module FIG. It is sectional drawing which shows typically the principal part of the state joined in the package main body.
[0045]
Book Second The semiconductor laser module 30 of the embodiment includes: FIG. and FIG. As shown, the bottomed and box-shaped package body 31 having an open top surface, a bottom wall 31d formed integrally with the package body 31, and a Peltier element module 30a disposed in the package body 31 Composed. A heat sink (not shown) is provided on the lower surface of the bottom wall 31d. Here, a large number (for example, 32) of electrode patterns (second electrodes) 32, 32, 32... Are provided on the upper surface of the bottom wall 31d. For example, the electrode sheet has a plate-like green sheet as a bottom wall. State Sometimes, a refractory metal (for example, tungsten (W) or the like) is attached in a pattern and then integrated with the green body that becomes the package body 31. The bottom wall 31d extends from the outer peripheral portion of the package body 31 and is provided with a flange portion. The flange portion is provided with a through hole for fixing the package body 31 to other components.
[0046]
In addition, the bottomed package body 31 is a Fernico alloy of 54%, 29% Ni, 17% Co (trade name: Kovar) or an alloy of 58% Fe, 42% Ni, as in the first embodiment. (Trade name: 42 alloy). And, like the first embodiment described above, insulating materials 31a and 31a made of ceramic provided with lead wires 31b are provided on the pair of side walls of the bottomed package body 31 with hermetic seals, A light extraction window 31c is provided on the side wall.
[0047]
The thermoelectric element (Peltier element) module 30a includes a substrate 33, an electrode pattern (first electrode) 34 formed on the substrate 33, a P-type semiconductor compound element 35a, an N-type semiconductor compound element 35b, and a conductive pattern. 36. The substrate 33 is made of a ceramic material such as alumina (Al ₂ O _Three ), Alumina nitride (AlN), silicon carbide (SiC), and the like, and an electrode pattern 34 is formed on the substrate 33 by copper (Cu) plating and etching.
[0048]
Both ends of the P-type semiconductor compound element 35a and the N-type semiconductor compound element 35b are plated with nickel, and solder plating is applied on the nickel plating. The P-type semiconductor compound elements 35a and the N-type semiconductor compound elements 35b are alternately arranged, and are electrically connected in series in the order of P, N, P, and N by the electrode pattern 34 and the conductive pattern 36. Note that the ends and electrode patterns of the P-type semiconductor compound element 35a and the N-type semiconductor compound element 35b 34 The conductive pattern 36 is soldered with second bonding materials 37 and 38 made of tin (Sn) -antimony (Sb) solder having a melting point (Tm) of about 240 ° C.
[0049]
Then configured as above Second A method for manufacturing the semiconductor laser module 30 of the embodiment will be described.
First, a box-shaped package body 31 having a bottom wall 31d provided with a large number of electrode patterns 32 on the upper surface is prepared, and a substrate 33 having a large number of electrode patterns 34 formed on the surface and nickel on both ends. A P-type semiconductor compound element 35a and an N-type semiconductor compound element 35b, which are plated and solder-plated on the nickel plating, and a conductive pattern (conductive layer) 36 are prepared.
[0050]
(1) First joining process
Next, P-type semiconductor compound elements 35a and N-type semiconductor compound elements 35b are alternately arranged on a large number of electrode patterns 34 formed on the substrate 33, so that the P-type semiconductor compound elements 35a and the N-type semiconductor compound elements 35b are formed. The melting point (Tm) is about 240 ° C. between the electrode pattern 34 and one end of the P-type semiconductor compound element 35a and the N-type semiconductor compound element 35b so that they are electrically connected in series via the electrode pattern 34. It solders with the 2nd joining material 37 which consists of a certain Sn-Sb solder.
[0051]
(2) Second joining process
Next, the P-type semiconductor compound element 35a and the N-type semiconductor compound element 35a and the N-type semiconductor compound element 35b are electrically connected in series with each other through the conductive pattern 36. A conductive pattern 36 is disposed on the other end of the element 35b, and the conductive pattern 36 and the other end of the P-type semiconductor compound element 35a and the N-type semiconductor compound element 35b are connected to a second bonding material, for example, a melting point (Tm ) Is soldered with the second bonding material 38 made of Sn—Sb solder having a temperature of about 240 ° C. to produce a thermoelectric element (Peltier element) module 30a. In addition, you may perform this 1st joining process and 2nd joining process simultaneously, ie, one joining process.
[0052]
(3) Third joining step
Next, a third bonding material, for example, a solder cream 39 made of tin (Sn) -lead (Pb) eutectic solder having a melting point (Tm) of about 182 ° C. is formed on a large number of electrode patterns 32, 32, 32. Apply. Thereafter, the thermoelectric element (Peltier element) module 30a produced as described above is turned upside down in the package main body 31 so that the substrate 33 faces upward, and the electrode pattern 32 and the thermoelectric element (Peltier element) module 30a are arranged. It arrange | positions from the top so that the conductive pattern 36 of this may correspond. Next, after heating to a temperature of about 182 ° C., the thermoelectric element (Peltier element) module 30 a is cooled while being pressed against the bottom wall 31 d of the package body 31, and the electrode pattern 32 and the conductive pattern 36 are joined with the solder cream 39. To do.
[0053]
Next, Similar to FIG. On the substrate 33, a header on which a semiconductor laser element is mounted via a heat sink (not shown), a lens holder on which a lens is fixed, and a base plate on which a light receiving element is mounted are fixed by soldering, and an upper lid is attached to the upper end portion of the package body 31. Are hermetically sealed to form a semiconductor laser module. A heat sink (not shown) is provided on the lower surface of the bottom cover 31d, and heat generated by the semiconductor laser element and the Peltier element is radiated to the outside through the heat sink.
[0054]
As mentioned above, Second In the embodiment, one end of the plurality of Peltier elements 35 a and 35 b is bonded by the second bonding material 37 on the substrate 33 on which the electrode pattern (first electrode) 34 is formed in the first bonding step. Thereafter, in the second bonding step, the conductive pattern (conductive layer) 36 is bonded to the other end of the plurality of Peltier elements 35a and 35b by the second bonding material 38. The second bonding material 38 is used in the first bonding step. Since it is the same joining material as the second joining material 37 in FIG. Next, in the third bonding step, the other ends of the plurality of Peltier elements 35a and 35b are bonded to the electrode pattern (second electrode) 32 by the third bonding material 39. The third bonding material 39 is the second bonding material. Since the melting point is lower than that of 37 and 38, the second bonding materials 37 and 38 are not melted during the joining. As a result, the amount of brittle intermetallic compounds such as Ni—Sn and Ni—Au generated at the time of remelting is reduced, so that a joint with high joint strength is formed, and a highly reliable joint can be obtained. .
[0055]
Further, when the third bonding material 39 has the same melting point as that of the second bonding material 37, 38, there is a demerit that the second bonding material 37, 38 is remelted in the third bonding step, but it melts at the same time and solidifies simultaneously. Therefore, there is an advantage that the thermal stress generated during solidification is particularly small. This merit is particularly great in terms of long-term reliability. Therefore, the melting points of the second bonding materials 37 and 38 and the third bonding material 39 can be selected depending on the application.
[0066]
3 . Third Example
Next, Third Example FIG. and FIG. Based on In addition, FIG. Is a book Third It is a perspective view which shows the package main body of an Example typically. Also, FIG. (A) is a book Third It is a cross-sectional view schematically showing the main part of the thermoelectric element module of the example, FIG. (B) shows this thermoelectric module FIG. It is sectional drawing which shows typically the principal part of the state joined in the package main body.
[0067]
Book Third The semiconductor laser module 50 of the embodiment includes: FIG. and FIG. As shown in FIG. 1, a bottomed and box-shaped package main body 51 having an open top surface, a bottom wall 51d molded integrally with the package main body 51, and a Peltier element module 50a disposed in the package main body 51 Composed. A heat sink (not shown) is provided on the bottom surface of the bottom wall 51d. Here, a large number (for example, 32) of electrode patterns (second electrodes) 52, 52, 52... Are provided on the upper surface of the bottom wall 51d. For example, the electrode sheet has a plate-like green sheet as a bottom wall. State Sometimes, a refractory metal (for example, tungsten (W)) is applied in a pattern and then integrated with the green body that becomes the package body 51. The bottom wall 51d is formed to have the same size as the outer peripheral portion of the package body 51.
[0068]
In addition, the bottomed package body 51 is a Fernico alloy of 54%, Ni 29%, Co 17% (trade name: Kovar) or an alloy of Fe 58%, Ni 42%, as in the first embodiment. (Trade name: 42 alloy). Further, as in the first embodiment, the pair of side walls of the bottomed package body 51 are provided with insulating materials 51a and 51a made of ceramic provided with lead wires 51b by hermetic seals, A light extraction window 51c is provided on the side wall. Book Third In the embodiment, a reinforcing plate 50b made of a ceramic such as Cu-W, Kovar, or alumina that reinforces the strength of the bottom wall 51d is joined to the lower end of the bottomed package body 51. A through-hole for fixing the package main body 51 to other parts is provided at the end of the reinforcing plate 50b.
[0069]
The thermoelectric element (Peltier element) module 50a includes a substrate 53, an electrode pattern (first electrode) 54 formed on the substrate 53, a P-type semiconductor compound element 55a, an N-type semiconductor compound element 55b, and a conductive pattern. 56. The substrate 53 is a ceramic material such as alumina (Al ₂ O _Three ), Alumina nitride (AlN), silicon carbide (SiC), and the like, and an electrode pattern 54 is formed on the substrate 53 by copper (Cu) plating and etching.
[0070]
Both ends of the P-type semiconductor compound element 55a and the N-type semiconductor compound element 55b are plated with nickel, and solder plating is applied on the nickel plating. The P-type semiconductor compound elements 55a and the N-type semiconductor compound elements 55b are alternately arranged, and are electrically connected in series in the order of P, N, P, and N by the electrode pattern 54 and the conductive pattern 56. End portions and electrode patterns of the P-type semiconductor compound element 55a and the N-type semiconductor compound element 55b 54 The conductive pattern 56 is soldered by second bonding materials 57 and 58 made of tin (Sn) -antimony (Sb) solder having a melting point (Tm) of about 240 ° C.
[0071]
Then configured as above Third Example semiconductor laser module 50 The manufacturing method will be described.
First, a box-shaped package main body 51 having a bottom wall 51d provided with a large number of electrode patterns 52 on the upper surface and a reinforcing plate 50b provided with through holes for fixing the package main body 51 to other components are prepared. In addition, a substrate 53 having a large number of electrode patterns 54 formed on the surface thereof, and a P-type semiconductor compound element 55a and an N-type semiconductor compound element 55b in which both ends are plated with nickel and solder plated on the nickel plating, The conductive pattern 56 is prepared.
[0072]
(1) First joining process
First, the reinforcing plate 50b is fixed to the lower surface of the box-shaped package body 51 having the bottom wall 51d provided with a large number of electrode patterns 52 on the upper surface with a first bonding material, for example, silver wax or glass.
[0073]
(2) Second joining process
Next, P-type semiconductor compound elements 55a and N-type semiconductor compound elements 55b are alternately arranged on a large number of electrode patterns 54 formed on the substrate 53, so that the P-type semiconductor compound elements 55a and the N-type semiconductor compound elements 55b are formed. The melting point (Tm) of the electrode pattern 54 and one end of the P-type semiconductor compound element 55a and the N-type semiconductor compound element 55b is about 240 ° C. so that they are electrically connected in series via the electrode pattern 54. It solders with the 2nd joining material 57 which consists of a certain Sn-Sb solder.
[0074]
(3) Third joining step
Subsequently, the P-type semiconductor compound element 55a and the N-type semiconductor compound element 55a and the N-type semiconductor compound element 55b are electrically connected in series with each other through the conductive pattern 56. A conductive pattern (conductive layer) 56 is disposed on the other end of the element 55b, and the conductive pattern 56 and the other end of the P-type semiconductor compound element 55a and the N-type semiconductor compound element 55b are connected to a second bonding material, for example, The thermoelectric element (Peltier element) module 50a is manufactured by soldering with a second bonding material 58 made of Sn—Sb solder having a melting point (Tm) of about 240 ° C. In addition, this 2nd joining process and 3rd joining process May be performed simultaneously, that is, in one joining step.
[0075]
(4) Fourth joining step
Next, a third bonding material, for example, a solder cream 59 made of tin (Sn) -lead (Pb) eutectic solder having a melting point (Tm) of about 182 ° C. is formed on a large number of electrode patterns 52, 52, 52. Apply. Thereafter, the thermoelectric element (Peltier element) module 50a manufactured as described above is turned upside down in the package main body 51 so that the substrate 53 faces upward, and the electrode pattern 52 and the thermoelectric element (Peltier element) module 50a are arranged. It arrange | positions from the top so that the conductive pattern 56 may correspond. Next, after heating to a temperature of about 182 ° C., the thermoelectric element (Peltier element) module 50 a is cooled while being pressed against the bottom wall 51 d of the package body 51, and the electrode pattern 52 and the conductive pattern 56 are joined with the solder cream 59. To do.
[0076]
Next, Similar to FIG. On the substrate 53, a header on which a semiconductor laser element is mounted via a heat sink (not shown), a lens holder on which a lens is fixed, and a base plate on which a light receiving element is mounted are fixed by soldering. Are hermetically sealed to form a semiconductor laser module. Na Oh, Bottom wall 51 of package body 51 d A heat sink (not shown) is provided on the lower surface of the bonded reinforcing plate 50b, and heat generated by the semiconductor laser element and the Peltier element is radiated to the outside through the heat sink.
[0077]
As mentioned above, Third In the embodiment, one end of the plurality of Peltier elements 55 a and 55 b is bonded by the second bonding material 57 on the substrate 53 on which the electrode pattern (first electrode) 54 is formed in the second bonding step. Thereafter, in the third bonding step, the conductive pattern (conductive layer) 56 is bonded to the other end of the plurality of Peltier elements 55a and 55b by the second bonding material 58. The second bonding material 58 is bonded to the second bonding step. Since the second bonding material 57 is the same as the second bonding material 57, it is hardly melted. Next, in the fourth bonding step, the other ends of the plurality of Peltier elements 55a and 55b are bonded to the electrode pattern (second electrode) 52 by the third bonding material 59. The third bonding material 59 is the second bonding material. Since the melting point is lower than those of 57 and 58, the second bonding materials 57 and 58 are not melted during this joining. As a result, the amount of brittle intermetallic compounds such as Ni—Sn and Ni—Au generated at the time of remelting is reduced, so that a joint with high joint strength is formed, and a highly reliable joint can be obtained. .
[0078]
Further, when the third bonding material 59 has the same melting point as the second bonding materials 57 and 58, there is a demerit that the second bonding materials 57 and 58 are remelted in the fourth bonding step, but they are simultaneously melted and simultaneously solidified. Therefore, there is an advantage that the thermal stress generated during solidification is particularly small. This merit is particularly great in terms of long-term reliability. Therefore, the melting points of the second bonding materials 57 and 58 and the third bonding material 59 can be selected depending on the application.
[0089]
As described above, in the present invention, the first bonding material is a bonding material having a melting point higher than that of the second bonding material, and the second bonding material is a bonding material having a melting point higher than that of the third bonding material or the third bonding material. Since the bonding material having the same melting point defines the temperature relationship between the bonding materials, a bonding portion with high bonding strength is formed and a highly reliable bonding portion can be obtained.
[0090]
The above-mentioned number 1 fruit In the example, the package body uses a material having good thermal conductivity such as Kovar, and the bottom cover uses a ceramic material having a good thermal conductivity and a thermal expansion coefficient almost equal to the thermal expansion coefficient of the package body. However, the present invention is not limited to this. For example, the package body may be made of a ceramic material with poor thermal conductivity, and the bottom cover may be made of a ceramic material with good thermal conductivity (for example, aluminum nitride). Also, 2nd to 3rd When using a bottomed package body in which the bottom wall is integrated as in the embodiment, a functionally graded material whose thermal conductivity gradually changes may be used, or different materials that can be simultaneously sintered may be used.
[0091]
If a thin insulating layer is provided between the second electrode and the bottom lid or the bottom wall, the second electrode can be patterned with a thin film or a thick film, so that the second electrode can be easily formed. . Furthermore, if a metallized layer for bonding the upper lid is provided on the upper part of the package body, or if a metallized layer for bonding the heat sink is provided on the bottom surface of the bottom lid or the bottom wall, a material having further excellent bonding strength can be obtained. It becomes like this.
[Brief description of the drawings]
FIG. 1 is a diagram showing a package main body and a bottom lid thereof according to a first embodiment.
2 is a diagram showing a thermoelectric element module according to a first embodiment and a state in which the thermoelectric element module is joined in the package body of FIG. 1; FIG.
[Fig. 3] Second It is a figure which shows the package of an Example.
[Fig. 4] Second Example thermoelectric module and the thermoelectric module FIG. It is a figure which shows the state joined in the package main body.
[Figure 5] Third It is a figure which shows the package main body of an Example.
[Fig. 6] Third Example thermoelectric module and the thermoelectric module FIG. It is a figure which shows the state joined in the package main body.
FIG. 7 is a cross-sectional view schematically showing a conventional semiconductor laser module.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Semiconductor laser module, 10a ... Peltier device module, 11 ... Package body, 12a ... Electrode pattern (second electrode), 13 ... Substrate, 13a ... Electrode pattern (first electrode), 14a ... P-type semiconductor compound device, 14b ... N-type semiconductor compound element, 15 ... conductive pattern (conductive layer), 16 ... second bonding material, 17 ... second bonding material, 18 ... third bonding material (solder cream), 30 ... semiconductor laser module, 30a ... Peltier Element module 31 ... Package body 31d ... Bottom wall 32 ... Electrode pattern (second electrode) 33 ... Substrate 34 ... Electrode pattern (first electrode) 35a ... P-type semiconductor compound element 35b ... Type semiconductor compound Element, 36 ... conductive pattern (conductive layer), 37 ... second bonding material, 38 ... second bonding material, 39 ... third bonding material (solder cream), 50 ... Conductor laser module, 50a ... Peltier element module, 51 ... package body, 51d ... bottom wall, 52 ... electrode pattern (second electrode), 53 ... substrate, 54 ... electrode pattern (first electrode), 55a ... P-type semiconductor compound Element, 55b ... type semiconductor compound element, 56 ... conductive pattern (conductive layer), 57 ... second bonding material, 58 ... second bonding material, 59 ... third bonding material (solder cream)

Claims (7)

A semiconductor laser module that houses a semiconductor laser element in a package body, and cools the semiconductor laser element in the package body,
A first electrode formed on a substrate thermally coupled to the semiconductor laser element;
A second electrode formed on a bottom lid for sealing the package body;
A plurality of Peltier elements connected between the first and second electrodes;
A first bonding material for bonding the package body and the bottom lid;
A second bonding material for bonding the first electrode and one end of the plurality of Peltier elements;
A third bonding material for bonding the second electrode and the other end of the plurality of Peltier elements via a conductive layer ;
The first bonding material is a bonding material having a melting point higher than that of the second bonding material, and the second bonding material has a melting point equal to that of the bonding material having a melting point higher than that of the third bonding material or the third bonding material. A semiconductor laser module which is a bonding material. A semiconductor laser module that houses a semiconductor laser element in a package body, and cools the semiconductor laser element in the package body,
A first electrode formed on a substrate thermally coupled to the semiconductor laser element;
A second electrode formed on a bottom wall formed integrally with the package body;
A plurality of Peltier elements connected between the first and second electrodes;
A second bonding material for bonding the first electrode and one end of the plurality of Peltier elements;
A third bonding material for bonding the second electrode and the other end of the plurality of Peltier elements via a conductive layer ;
2. The semiconductor laser module according to claim 1, wherein the second bonding material is a bonding material having a melting point higher than that of the third bonding material or a bonding material having the same melting point as that of the third bonding material. A semiconductor laser module that houses a semiconductor laser element in a package body, and cools the semiconductor laser element in the package body,
A first electrode formed on a substrate thermally coupled to the semiconductor laser element;
A second electrode formed on a bottom wall formed integrally with the package body;
A plurality of Peltier elements connected between the first and second electrodes;
A reinforcing plate for reinforcing a bottom wall formed integrally with the package body and a first bonding material for joining the bottom wall;
A second bonding material for bonding the first electrode and one end of the plurality of Peltier elements;
A third bonding material for bonding the second electrode and the other end of the plurality of Peltier elements via a conductive layer ;
The first bonding material is a bonding material having a melting point higher than that of the second bonding material, and the second bonding material has a melting point equal to that of the bonding material having a melting point higher than that of the third bonding material or the third bonding material. A semiconductor laser module which is a bonding material. The first electrode is a thin film or a thick film patterned on the substrate, and the second electrode is a thin film or a thick film patterned on the bottom lid or the bottom wall. The semiconductor laser module according to any one of claims 1 to 3 . A method of manufacturing a semiconductor laser module, wherein a semiconductor laser element is accommodated in a package body, and the semiconductor laser element is cooled in the package body,
A first joining step of joining a bottom lid for sealing the package body on which the second electrode is formed to the lower end of the package body with a first joining material;
A second bonding step of bonding one end of a plurality of Peltier elements on the substrate on which the first electrode is formed by a second bonding material having a melting point lower than that of the first bonding material;
A third joining step in which a conductive layer is joined to the other end of the plurality of Peltier elements by the second joining material to form a thermoelectric element module ;
A fourth bonding step of bonding the conductive layer bonded to the thermoelectric element module to the second electrode by a third bonding material having a melting point lower than that of the second bonding material or a third bonding material having a melting point equal to that of the second bonding material; A method for manufacturing a semiconductor laser module. A method of manufacturing a semiconductor laser module, wherein a semiconductor laser element is accommodated in a package body, and the semiconductor laser element is cooled in the package body,
A first bonding step of bonding one end of a plurality of Peltier elements with a second bonding material on the substrate on which the first electrode is formed;
A second joining step in which a conductive layer is joined to the other end of the plurality of Peltier elements by the second joining material to form a thermoelectric element module ;
A third bonding material having a melting point lower than that of the second bonding material or a second bonding material formed on a bottom wall formed integrally with the package main body by bonding the conductive layer bonded to the thermoelectric element module. And a third bonding step of bonding with a third bonding material having the same melting point. A method of manufacturing a semiconductor laser module, wherein a semiconductor laser element is accommodated in a package body, and the semiconductor laser element is cooled in the package body,
A first joining step of joining an outer surface of a bottom wall formed integrally with the package body having a second electrode formed on an inner surface to a reinforcing plate that reinforces the bottom wall with a first joining material;
A second bonding step of bonding one end of a plurality of Peltier elements on the substrate on which the first electrode is formed by a second bonding material having a melting point lower than that of the first bonding material;
A third joining step in which a conductive layer is joined to the other end of the plurality of Peltier elements by the second joining material to form a thermoelectric element module ;
A third bonding material having a melting point lower than that of the second bonding material or a second bonding material formed on a bottom wall formed integrally with the package main body by bonding the conductive layer bonded to the thermoelectric element module. And a third bonding step of bonding with a third bonding material having the same melting point.

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