CN112636161A

CN112636161A - Heat dissipation packaging structure with resonant cavity semiconductor laser and packaging method thereof

Info

Publication number: CN112636161A
Application number: CN202011506785.1A
Authority: CN
Inventors: 毛虎; 邱智贤; 毛森; 焦英豪
Original assignee: Lewei Semiconductor Technology Jiaxing Co ltd
Current assignee: Lewei Semiconductor Technology Jiaxing Co ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-04-09

Abstract

The invention provides a heat dissipation packaging structure with a resonant cavity semiconductor laser and a packaging method thereof, wherein the packaging structure comprises a heat sink, a conducting layer arranged at the top of the heat sink, a transition electrode arranged on the conducting layer and the semiconductor laser, the heat sink comprises a DBC structural layer and a DPC structural layer arranged on the DBC structural layer, the semiconductor laser and the transition electrode are both electrically connected with the conducting layer, the semiconductor laser comprises a substrate, a metal layer arranged on the substrate, a silicon-oxygen compound filled between adjacent metals, an ALD (atomic layer deposition) film layer, an insulating medium layer, a PMMA (polymethyl methacrylate) layer and an active layer which are sequentially arranged on the metal layer and the structural layer formed by filling the silicon-oxygen compound, an annular cavity penetrating through the ALD film layer, the insulating medium layer and the PMMA layer is formed in. The invention greatly improves the heat dissipation effect and the performance of the laser.

Description

Heat dissipation packaging structure with resonant cavity semiconductor laser and packaging method thereof

Technical Field

The invention relates to the technical field of semiconductor photoelectricity, in particular to a heat dissipation packaging structure with a resonant cavity semiconductor laser and a packaging method thereof.

Background

The semiconductor laser has the characteristics of high efficiency, small volume, light weight, long service life, simple manufacture, low cost and the like; it has found wide application in laser printing, laser ranging, laser radar, fiber optic communication, infrared illumination, atmosphere monitoring, chemical spectroscopy, etc. In the early days, semiconductor lasers generally employed photonic crystal microcavities or dielectric cavities formed by plating multiple layers of highly reflective dielectric films on both ends of the active layer as optical resonant cavities. In 2007, theoretical research results of a.v. mas lov and c.z.ning show that a metal cavity has stronger local capability to electromagnetic wave modes than a dielectric cavity, and thus they believe that coating a metal film on a semiconductor nanowire can reduce the size of a nanowire laser. In addition, the volume occupied by the metal reflector is smaller than that occupied by the multilayer high-reflection dielectric film and the photonic crystal reflector, and the size of the semiconductor laser is reduced. Therefore, semiconductor lasers based on metal microcavities have become a focus of research in recent years.

The simplest method for manufacturing a metal cavity on a semiconductor material is to cover a metal film on the surface of the semiconductor material so as to form a metal reflector. The metal reflector and the metal film on the surface of the semiconductor material jointly form a metal cavity which is used as an optical resonant cavity of the laser. Although this manufacturing method is simple, the height of the metal mirror is limited by the thickness of the semiconductor material, resulting in large loss of the metal cavity, so that the oscillation threshold of the laser is high.

Furthermore, since light is emitted from various angles, the light is diffused, which causes the phenomena of light mixing, uneven light emission, low brightness, and the like, which affect the effect.

For a traditional single-mode laser, especially for high power, a separate refrigerator is required for cooling and radiating heat for the laser during normal operation. While the most common heat sinks are currently of three types: cooling with circulating cooling water, cooling with air, and cooling with semiconductor refrigerator. The laser manufactured by the existing method has huge volume, and the performance and the characteristics of the semiconductor laser cannot be well exerted and embodied in many occasions.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a heat dissipation package structure with a resonant cavity semiconductor laser and a packaging method thereof, which are capable of facilitating the packaging of the semiconductor laser for preventing light mixing, facilitating the heat dissipation and reducing the oscillation threshold of the laser.

Based on the above purpose, the invention provides a heat dissipation packaging structure with a resonant cavity semiconductor laser, which comprises a heat sink, a conducting layer arranged on the top of the heat sink, and a transition electrode and a semiconductor laser which are arranged on the conducting layer, wherein the heat sink comprises a DBC structural layer and a DPC structural layer arranged on the DBC structural layer, the semiconductor laser and the transition electrode are both electrically connected with the conducting layer, the semiconductor laser comprises a substrate, a metal layer arranged on the substrate, a silicon-oxygen compound filled between adjacent metals, an ALD (atomic layer deposition) film layer, an insulating medium layer, a PMMA (polymethyl methacrylate) layer and an active layer which are sequentially arranged on the metal layer and the structural layer formed by filling the silicon-oxygen compound, an annular cavity penetrating through the ALD film layer, the insulating medium layer and the PMMA layer.

And a ventilation structure or a water passing structure is arranged in the DBC structural layer and the DPC structural layer.

The water passing structure is a snake-shaped water cooling channel, and the DBC structural layer is communicated with the snake-shaped water cooling channel in the DPC structural layer.

The packaging structure further comprises a fan arranged at the bottom of the heat sink.

And a fin group is arranged between the heat sink and the fan.

And the transition electrode is provided with an overcurrent protection device electrically connected with the transition electrode.

The over-current protection device is a fuse.

The insulating medium layer is made of magnesium difluoride, aluminum oxide, silicon dioxide or lithium fluoride, and the thickness of the insulating medium layer is 5-100 nm.

The packaging structure further comprises a shell, the semiconductor laser is arranged inside the shell, and an emission window corresponding to the semiconductor laser is formed in the shell.

The packaging method of the heat dissipation packaging structure with the resonant cavity semiconductor laser comprises the following steps:

bonding a DPC structural layer on the DBC structural layer to form a heat sink, and electrically connecting a semiconductor laser and a transition electrode on a conductive layer at the top of the heat sink;

mounting the overcurrent protection device on the transition electrode, and electrically connecting the overcurrent protection device with the transition electrode;

thirdly, mounting fins and a fan at the bottom of the heat sink;

and step four, packaging the anti-mixing semiconductor laser with the integrated heat dissipation structure obtained in the step three in a shell, and enabling a fan to penetrate through the bottom of the shell and extend outwards.

The reflecting layer is a silver film layer formed by magnetron sputtering.

The active layer is a semiconductor nano sheet or a semiconductor nano wire.

The semiconductor nano sheet or the semiconductor nano wire is made of one of cadmium selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium gallium nitride and indium gallium arsenic phosphorus; the thickness of the semiconductor nano-sheet or the semiconductor nano-wire is 50-300 nm.

The thickness of the metal layer is 50-200nm, and the metal layer is made of metal materials.

The base plate is a silicon substrate.

The preparation method of the anti-mixed light semiconductor laser comprises the following steps:

step one, preparing a metal layer on a substrate;

filling a silicon-oxygen compound in the gap space of the metal layer;

step three, preparing an ALD film layer on the metal layer and the structural layer formed by filling the silicon oxide compound;

step four, evaporating and plating an insulating medium layer on the ALD film layer;

fifthly, ink-jet printing of the PMMA layer on the insulating medium layer;

step six, coating glue on the PMMA layer, and then forming an annular cavity by exposing, developing and sequentially etching the PMMA layer downwards until the ALD film layer;

step seven, sputtering above the annular hole cavity by adopting a magnetron sputtering mode to form a silver film layer filling the annular hole cavity, and etching the silver film layer on the surface to form a silver film layer annular hole cavity;

and step eight, transferring the active layer to the surface of the PMMA layer, which is far away from the insulating medium layer, by using a micro-operation system, and enabling the active layer to be tightly attached to the PMMA layer.

The metal layer includes a plurality of metal sections that interval set up, and the interval between the adjacent metal section is less than 10000A and is greater than 5000A.

And etching the surface silver film layer in the seventh step by gluing, exposing and developing, and then completely etching the surface silver film layer to leave only the silver film layer in the annular cavity, wherein the thickness of the annular cavity of the silver film layer is 5000A.

The invention has the beneficial effects that:

1. according to the invention, multiple heat dissipation is carried out on the anti-mixing semiconductor laser through the heat sink, the fan, the fin group and the water cooling channel, so that the heat dissipation effect is greatly improved, and the performance of the semiconductor laser is improved. Wherein, the heat sink is formed by bonding the DPC structural layer on the DBC structural layer, and the heat dissipation effect is better.

2. The overcurrent protection device can well protect the semiconductor laser, and avoids the damage to the semiconductor laser caused by overlarge current.

3. The silver film in the annular cavity is used as an optical resonant cavity of the laser, and because the reflectivity of the silver film layer is very high, when light is diffused, the light can be reflected back due to the existence of silver, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused to an adjacent external space are controlled. The height of the annular cavity is reasonably set, so that the loss of an optical waveguide mode in the annular cavity at the cavity mirror is reduced, and the oscillation threshold of laser is reduced.

4. The insulating medium layer positioned between the active layer and the metal layer can reduce the propagation loss of the optical waveguide mode in the annular cavity, and the propagation loss of the optical waveguide mode can be further reduced by increasing the thickness of the insulating medium layer, thereby being beneficial to the formation of laser.

5. The semiconductor laser and the manufacturing method thereof can work at room temperature because the gain of the semiconductor nano-sheet or the semiconductor nano-wire is large and the loss of the annular hole cavity is small.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only one or more embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of a semiconductor laser according to the present invention;

FIG. 3 is a schematic structural view of an ALD film, an insulating dielectric layer and a PMMA layer formed on a metal layer and a structural layer filled with a silicon oxide compound according to the present invention;

FIG. 4 is a schematic view of the structure of the present invention after the PMMA layer is coated with glue;

FIG. 5 is a schematic structural diagram of the present invention after etching to form an annular cavity.

Labeled as:

1. a substrate; 2. a metal layer; 3. a silicone compound; 4. an ALD film layer; 5. an insulating dielectric layer; 6. a PMMA layer; 7. an active layer; 8. an annular bore; 9. photoresist; 100. a heat sink; 101. a conductive layer; 102. a semiconductor refrigerator; 103. a transition electrode; 104. a fin set; 105. a fan; 106. an overcurrent protection device; 108. a housing; 109. an emission window; 110. a through hole; 111. a DBC structural layer; 112. DPC structural layer.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure is further described in detail below with reference to specific embodiments.

It should be noted that technical terms or scientific terms used in the embodiments of the present specification should have a general meaning as understood by those having ordinary skill in the art to which the present disclosure belongs, unless otherwise defined. The use of "first," "second," and similar terms in the embodiments of the specification is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

As shown in fig. 1, a heat dissipation package structure with a resonant cavity semiconductor laser comprises a heat sink 100, a conductive layer 101 disposed on top of the heat sink 100, and a transition electrode 103 and a semiconductor laser disposed on the conductive layer 101, the heat sink 100 includes a DBC structural layer 111 and a DPC structural layer 112 disposed on the DBC structural layer 111, the semiconductor laser and the transition electrode 103 are electrically connected with the conductive layer 101, the semiconductor laser comprises a substrate 1, a metal layer 2 arranged on the substrate 1, a silicon oxide compound 3 filled between adjacent metals, an ALD film layer 4, an insulating medium layer 5, a PMMA layer 6 and an active layer 7 which are sequentially arranged on a structural layer formed by the metal layer 2 and the filled silicon oxide compound 3, an annular cavity 8 penetrating through the ALD film layer 4, the insulating medium layer 5 and the PMMA layer 6 is formed in the semiconductor laser, and a reflection film layer is arranged in the annular cavity 8.

In this embodiment, a ventilation structure or a water passage structure is provided in the DBC structural layer 111 and the DPC structural layer 112 for better heat exchange. In a preferred embodiment, the water passage structure is a serpentine water cooling channel. The water cooling channel comprises an inlet and an outlet which are respectively used for being connected with a circulating water cold source. The plane of the water cooling channel is parallel to the top surface of the heat sink, the water cooling channel penetrates through the DBC structural layer 111 and the DPC structural layer 112 in the heat sink, and the inlet and the outlet are both positioned on the side surface of the heat sink and on the same side surface of the heat sink. In the working process of the semiconductor laser, after the water cooling channel is connected with a circulating water cold source, the liquid flowing through the water cooling channel can take away the heat in the heat sink, so that the heat sink can further dissipate the heat of the semiconductor laser.

In order to further improve the heat dissipation effect, the package structure further includes a fan 105 disposed at the bottom of the heat sink 100 and a fin group 104 disposed between the fan and the heat sink. The heat dissipation of the heat sink can be accelerated through the fan, the heat dissipation area of the heat sink can be increased through the fin group, and therefore the semiconductor laser can be further dissipated through the fan and the fin group.

In a preferred embodiment of the present embodiment, the transition electrode 103 is provided with an overcurrent protection device 106 electrically connected to the transition electrode 103. The transition electrode is provided with a mounting groove (not shown), and the overcurrent protection device is arranged in the mounting groove. The transition electrode is connected with an external power supply through the overcurrent protection device, so that the semiconductor laser, the conducting layer, the transition electrode, the overcurrent protection device and the external power supply form an electric loop. The overcurrent protection device in this embodiment is a fuse, and when the magnitude of the current exceeds a certain value, the overcurrent protection device is disconnected, the electrical circuit is disconnected, that is, the transition electrode is disconnected from the external power supply, and the semiconductor laser stops working, so that the semiconductor laser is prevented from being damaged.

In a preferred embodiment, the package structure further includes a housing 108, and the housing includes an upper cover and a housing, and the upper cover is disposed on the housing. The semiconductor laser is disposed inside the housing 108, and an emission window 109 corresponding to the semiconductor laser is disposed on the housing 108. Preferably, the heat sink, the conductive layer, the transition electrode, the fin group and the overcurrent protection device are all located in the shell, and the fan is arranged at the bottom of the shell. An emission window 109 corresponding to a laser emission surface of the semiconductor laser is formed in the housing, and laser emitted by the semiconductor laser is emitted from the emission window 109. The shell is also provided with a through hole 110, and a lead connected with the semiconductor laser, the over-current protection device or the fan is connected with an external power supply through the through hole.

In this embodiment, the insulating dielectric layer 5 may be magnesium difluoride, aluminum oxide, silicon dioxide or lithium fluoride, and the thickness of the insulating dielectric layer 5 is 5-100 nm. In the present embodiment, the insulating dielectric layer 5 is made of magnesium difluoride. The thicker the thickness of the insulating dielectric layer, the smaller the propagation loss of the optical waveguide mode, and the lower the threshold value of laser formation.

As an alternative embodiment, the active layer 7 is a semiconductor nanosheet or a semiconductor nanowire.

As an optional implementation form, the semiconductor nanosheet or the semiconductor nanowire is made of one of cadmium selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium gallium nitride and indium gallium arsenic phosphide; the thickness of the semiconductor nano-sheet or the semiconductor nano-wire is 50-300 nm. In this embodiment, the active layer is a cadmium selenide nanosheet.

As an alternative embodiment, the thickness of the metal layer 2 is 50-200nm, and the metal layer 2 is made of a metal material. Such as one of gold, silver and aluminum, other metal materials can be used, and the invention is not limited by the simple substitution. In this embodiment, the metal layer is a gold film.

In the present embodiment, the silicon oxide SiOx is filled between adjacent metals in order to fill the gap between the metals, so as to prevent the common layer formed by the ALD film from filling the gap and conducting the adjacent metals, and in addition, if there is no silicon oxide layer, the ESD may be generated due to the point discharge phenomenon during the subsequent deposition.

The invention also provides a packaging method of the heat dissipation packaging structure with the resonant cavity semiconductor laser, which comprises the following steps:

thirdly, mounting fins and a fan at the bottom of the heat sink;

The preparation method of the anti-light-mixing semiconductor laser comprises the following steps:

step one, preparing a metal layer 2 on a substrate 1; the metal layer is formed by vapor deposition or sputtering, and the method of vapor deposition or sputtering is a known technique, and will not be described in more detail here. The thickness of the metal layer may be 800A to 1000A.

Filling a silicon oxide compound 3 in the gap space of the metal layer 2; specifically, a chemical vapor deposition method is adopted to fill the silicon-oxygen compound.

Step three, preparing an ALD film layer 4 on the structural layer formed by the metal layer 2 and the filling silicon oxide compound 3;

step four, evaporating and plating an insulating medium layer 5 on the ALD film layer 4; the insulating medium is magnesium difluoride, and a layer of insulating medium layer with the thickness of 10nm, namely a magnesium difluoride film, is evaporated on the ALD film layer 4 by a magnetron sputtering method, an electron beam evaporation method or a pulse laser deposition method.

Fifthly, printing a PMMA layer 6 on the insulating medium layer 5 in an ink-jet mode; preferably, the thickness of the PMMA layer is less than or equal to 10000A.

Sixthly, coating glue on the PMMA layer 6, and then sequentially etching downwards from the PMMA layer 6 to the ALD film layer 4 through exposure and development to form an annular cavity 8; specifically, photoresist 9 is coated on the PMMA layer, the structure on the substrate is exposed by an exposure machine, only a circle of hole cavity surrounding the active layer is exposed during exposure, the thickness of the hole cavity is 5000A (namely the distance from the inner wall to the outer wall of the hole cavity), the exposed substrate structure is developed and etched, the etching is complete and uniform during the etching process, and the hole cavity is etched until the ALD film layer. The PMMA layer, the insulating medium layer 5 and the ALD layer 7 can be etched away sequentially through three times of etching to form the annular cavity. The specific component concentration and etching temperature of the etching liquid can be obtained through a contrast experiment, and the optimized aim is to etch a structure with smooth and steep side wall. To reduce the standing wave effect in holographic exposure, a layer of anti-reflective film, which is available from Brewer Science corporation, may be coated on the PMMA layer before the photoresist is coated, and the positive photoresist is AZ MIR-701. The thickness of the antireflective film is about 150nm, and the thickness of the photoresist is about 300 nm.

Step seven, sputtering above the annular hole cavity 8 by adopting a magnetron sputtering mode to form a silver film layer filling the annular hole cavity 8, and etching the silver film layer on the surface to form the annular hole cavity 8 of the silver film layer; specifically, after the annular cavity is formed through the six etching steps, the Ag film layer is prepared in a magnetron sputtering mode, the whole surface of the Ag film layer covers the structure on the substrate, and the thickness of the Ag film layer is 300-500A. And then, gluing, exposing, developing and etching the substrate structure with the prepared Ag film layer, completely etching the Ag film layer with the surface of 300A-500A, and only leaving the Ag film layer in the hole cavity, wherein the annular hole cavity of the Ag film layer is 5000A in thickness.

And step eight, transferring the active layer 7 to the side, away from the insulating medium layer 5, of the PMMA layer 6 by using a micro-operation system, and enabling the active layer 7 to be tightly attached to the PMMA layer 6.

The silver film in the annular cavity is used as an optical resonant cavity of the laser, and because the reflectivity of the silver film layer is very high, when light is diffused, the light can be reflected back due to the existence of silver, so that the phenomena of light mixing, uneven light emission, low brightness and the like caused by the fact that the light is not diffused to an adjacent external space are controlled. The height of the annular cavity is reasonably set, so that the loss of an optical waveguide mode in the annular cavity at the cavity mirror is reduced, and the oscillation threshold of laser is reduced. The insulating medium layer positioned between the active layer and the metal layer can reduce the propagation loss of the optical waveguide mode in the annular cavity, and the propagation loss of the optical waveguide mode can be further reduced by increasing the thickness of the insulating medium layer, thereby being beneficial to the formation of laser.

In the packaging structure, multiple heat dissipation is performed on the anti-mixing semiconductor laser through the heat sink, the fan, the fin group and the water cooling channel, so that the heat dissipation effect is greatly improved, and the performance of the semiconductor laser is improved. Wherein, the heat sink is formed by bonding the DPC structural layer on the DBC structural layer, and the heat dissipation effect is better.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the present disclosure, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present description as described above, which are not provided in detail for the sake of brevity.

The embodiments of the present description are intended to embrace all such alternatives, modifications and variances that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalents, improvements, and the like that may be made within the spirit and principles of the embodiments described herein are intended to be included within the scope of the disclosure.

Claims

1. The utility model provides a heat dissipation packaging structure with resonant cavity semiconductor laser, its characterized in that, includes the heat sink, locates the conducting layer at heat sink top and locates transition electrode and semiconductor laser on the conducting layer, the heat sink includes the DBC structural layer and locates the DPC structural layer on the DBC structural layer, semiconductor laser and transition electrode all with conducting layer electric connection, semiconductor laser includes the base plate, locates the metal level on the base plate, fills the silica compound between adjacent metal, locate ALD rete, insulating dielectric layer, PMMA layer and the active layer on the metal level and the structural layer of filling silica compound formation in proper order, be formed with the annular vestibule that runs through ALD rete, insulating dielectric layer and PMMA layer in the semiconductor laser, be equipped with the reflection rete in the annular vestibule.

2. The heat dissipating package with a resonant cavity semiconductor laser as claimed in claim 1, wherein a venting structure or a water passing structure is disposed in the DBC structure layer and the DPC structure layer.

3. The heat-dissipating package structure of a resonant cavity semiconductor laser as claimed in claim 2, wherein the water-passing structure is a serpentine water-cooling channel, and the DBC structure layer communicates with the serpentine water-cooling channel in the DPC structure layer.

4. The heat dissipating package with a resonant cavity semiconductor laser as set forth in claim 1, further comprising a fan disposed at a bottom of the heat sink.

5. The heat dissipating package with a resonant cavity semiconductor laser as recited in claim 4, wherein a fin set is disposed between the heat sink and the fan.

6. The heat dissipating package with a resonant cavity semiconductor laser as recited in claim 1, wherein the transition electrode is provided with an over-current protection device electrically connected to the transition electrode.

7. The heat spreading package with a resonant cavity semiconductor laser as recited in claim 6, wherein the over-current protection device is a fuse.

8. The heat dissipation package structure of a resonant cavity semiconductor laser as recited in claim 1, wherein the insulating dielectric layer is magnesium difluoride, aluminum oxide, silicon dioxide, or lithium fluoride, and the thickness of the insulating dielectric layer is 5-100 nm.

9. The heat dissipating package with a resonant cavity semiconductor laser as recited in claim 1, further comprising a housing, wherein the semiconductor laser is disposed inside the housing, and the housing defines an emission window corresponding to the semiconductor laser.

10. A method of packaging a heat dissipating package with a resonant cavity semiconductor laser as claimed in claim 1 comprising the steps of:

thirdly, mounting fins and a fan at the bottom of the heat sink;