Edge laser package

Abstract

An edge laser package is characterized by comprising: an edge laser chip for emitting laser light; gold threads; the upper surface of the heat sink is provided with a first bonding pad and a second bonding pad; one pole of the edge laser chip is fixed on the second bonding pad, and the other pole of the edge laser chip is connected to the first bonding pad through the gold wire; the cover body is positioned above the heat sink, is connected with the heat sink in a sealing manner, and wraps the edge laser chip and the gold wire; and at least part of the cover body is transparent, so that the laser is emitted. The laser packaging structure has good heat dissipation conditions and air tightness, overcomes the defects of a conventional laser packaging scheme, prolongs the service life of the laser, and improves the technological mass production of the laser.

Description

Technical Field

[0001] The present invention relates to the technical field of laser packaging, and in particular to an edge laser packaging. Background Art

[0002] Edge-emitting lasers used in applications such as lidar, 3D structured light, and TOF have two common packaging forms: SMT packaging and TO packaging.

[0003] Conventional COS packaging mounts the laser horizontally on a heat sink. The laser has good heat dissipation conditions, but the package is not airtight, the laser cavity surface is easily contaminated by the environment, and the exposed gold wire is easily damaged.

[0004] A conventional TO package mounts the laser vertically onto a small heat sink or metal bracket, which is then vertically fixed to a sealed cylindrical wall, with electrodes connected via pins. The TO package is airtight, effectively protecting the laser chip and gold wires. It is a plug-in package. However, due to its limited heat dissipation, it cannot achieve high power. Its large size and vertically upward light emission direction hinder external optical design.

[0005] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0006] To this end, the present invention proposes an airtight COS packaging solution based on edge-emitting lasers, which has good heat dissipation conditions and airtightness, overcomes the shortcomings of the above-mentioned conventional laser packaging solutions, and improves the service life and process mass production of the laser.

[0007] The present invention provides an edge laser package, characterized by comprising:

[0008] Edge laser chip, used for emitting laser;

[0009] Gold thread;

[0010] a heat sink having a first solder pad and a second solder pad on an upper surface thereof;

[0011] One electrode of the edge laser chip is fixed to the second pad, and the other electrode of the edge laser chip is connected to the first pad via the gold wire;

[0012] The cover is located above the heat sink, is sealed with the heat sink, and wraps the edge laser chip and the gold wire; the cover is at least partially transparent to allow the laser to be emitted.

[0013] Optionally, the edge laser package is characterized in that the cover is made of at least two materials, including at least one of copper, aluminum, and ceramic, so as to improve the heat dissipation effect.

[0014] Optionally, the edge laser package is characterized in that the volume of the enclosed space formed by the cover and the heat sink is positively correlated with the power of the edge laser chip.

[0015] Optionally, the edge laser package is characterized in that a groove is provided in the cover body for allowing a gold wire to pass through, thereby fixing the upper surface of the edge laser chip.

[0016] Optionally, the edge laser package is characterized in that the minimum distance between the cover and the second pad is less than 1 mm.

[0017] Optionally, the edge laser package is characterized in that the gold wire is electrically connected to the first pad and the other pole of the edge laser chip by gold wire ball bonding or ultrasonic welding.

[0018] Optionally, the edge laser package is characterized in that the second soldering pad and the first soldering pad of the heat sink are both provided with a plating layer to improve welding quality and electrical connection performance.

[0019] Optionally, the edge laser package is characterized in that the heat sink includes a substrate, a first positive electrode, a first negative electrode, a second positive electrode, a second negative electrode, and a filling hole;

[0020] The first positive electrode and the first negative electrode are located on the upper surface of the substrate;

[0021] The second positive electrode and the second negative electrode are located on the lower surface of the substrate;

[0022] The substrate has the filling hole inside;

[0023] Conductive metal is contained in the filling hole and is used to connect the first positive electrode and the second positive electrode, and the first negative electrode and the second negative electrode.

[0024] Optionally, the edge laser package is characterized in that a solder area is provided at the center of the first negative electrode, and a size of the solder area is larger than that of the edge laser chip.

[0025] Optionally, the edge laser package is characterized in that the diameter of the filling hole is [0.05mm, 0.2mm].

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The edge laser chip of the present invention is mounted horizontally on the heat sink, which has a large contact surface and ensures good heat dissipation.

[0028] The edge laser chip of the present invention is fixed horizontally to the heat sink without changing the light emitting direction and light emitting surface size of the laser, and is more easily adapted to compact optical design.

[0029] The surface of the laser of the present invention is provided with a cover body, which can protect the gold wire from external collision damage during production and use.

[0030] The laser of the present invention realizes airtight packaging, which can prevent dust in the air from being adsorbed on the laser cavity surface and causing damage.

[0031] The laser package airtight cavity of the present invention is filled with nitrogen or clean dry air, which can further prevent the influence of water vapor in the air and other volatile gases in the production environment on the laser, thereby increasing the service life of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without inventive work. Other features, purposes and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0033] Figure 1 This is a schematic structural diagram of an edge laser package according to an embodiment of the present invention;

[0034] Figure 2 1 is a side view schematic diagram of an edge laser package according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic structural diagram of a groove in an embodiment of the present invention;

[0036] Figure 4 This is a schematic structural diagram of a heat sink in an embodiment of the present invention;

[0037] Figure 5 is a top view of a heat sink according to an embodiment of the present invention;

[0038] Figure 6 This is a side view of a heat sink in an embodiment of the present invention.

[0039] 1- housing;

[0040] 2-sided laser chip;

[0041] 3-Gold thread;

[0042] 4-heat sink;

[0043] 5-Substrate;

[0044] 6- first negative electrode;

[0045] 7- second negative electrode;

[0046] 8- first positive electrode;

[0047] 9- second positive electrode;

[0048] 10-Irrigation hole;

[0049] 11- conductive metal;

[0050] 12-Solder area;

[0051] 13-inner surface of the cover;

[0052] 14- outer surface of the cover;

[0053] 15-groove; DETAILED DESCRIPTION

[0054] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0055] The terms "first," "second," "third," "fourth," and the like (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the invention described herein, for example, can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatus.

[0056] An edge laser package provided by an embodiment of the present invention is intended to solve the problems existing in the prior art.

[0057] The present invention can package edge-emitting lasers into airtight SMT devices, prevent damage to laser chips and gold wires during production and use, and increase the working life of the lasers. It is applicable to fields such as laser radar, 3D structured light, and TOF.

[0058] The "one pole" in this specification can be a positive pole or a negative pole, and the "other pole" is another pole different from the "one pole". When the "one pole" is a positive pole, the "other pole" is a negative pole; when the "one pole" is a negative pole, the "other pole" is a positive pole. In order to make the description of this specification clearer, some embodiments in this specification are explained by taking "one pole" as a negative pole and "the other pole" as a positive pole as an example, and no additional explanation is given. It can be understood by those skilled in the art that the "positive pole" in these embodiments can replace the "negative pole", and accordingly, the "negative pole" can also be replaced with the "positive pole". This is something that those skilled in the art can choose according to the application scenario and does not exceed the scope of this specification.

[0059] The following describes in detail the technical solutions of the present invention and how the technical solutions of this application solve the above-mentioned technical problems using specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The following embodiments of the present invention are described in conjunction with the accompanying drawings.

[0060] like Figure 1 and Figure 2 As shown, an edge laser package in an embodiment of the present invention includes:

[0061] The edge laser chip 2 is used for emitting laser light.

[0062] Specifically, the edge laser chip 2 is the core component of the entire package, its primary function being to emit laser light. Through its unique semiconductor structure and operating principle, it generates stimulated radiation under conditions such as injected current, thereby outputting a laser beam with high directivity, high monochromaticity, and high brightness.

[0063] The edge laser chip 2 has two electrodes, a positive electrode and a negative electrode. The negative electrode is fixed to the second pad of the heat sink, providing stable electrical connection and mechanical support for the chip. The positive electrode is connected to the first pad of the heat sink via gold wire, ensuring that current can flow smoothly into the chip and enable it to operate normally and generate laser light.

[0064] Factors such as the material, structure, and manufacturing process of edge laser chips directly influence key performance indicators such as the laser's output power, wavelength, and beam quality. Different application scenarios also place varying demands on chip performance. For example, in optical communications, chips require high modulation rates and stable wavelengths, while laser processing prioritizes high-power output capabilities.

[0065] Gold wire 3.

[0066] Specifically, gold wire 3, a highly conductive material, is used to connect the positive electrode of the edge laser chip to the first pad of the heat sink. Gold's excellent electrical conductivity, oxidation resistance, and chemical stability ensure a good electrical connection between the chip and the heat sink over long periods of operation, reducing contact resistance and ensuring stable current transmission, thus enabling stable laser operation.

[0067] Gold wire also has a certain degree of flexibility and mechanical strength. It can be appropriately bent and stretched during the packaging process to adapt to the spatial layout between the chip and the heat sink. At the same time, it can withstand a certain amount of external force and is not easy to break, thus ensuring the reliability of the connection.

[0068] For some applications that require high signal transmission quality, the low inductance and low resistance characteristics of gold wire can help reduce loss and interference during signal transmission and improve the performance of the laser.

[0069] The heat sink 4 has a first solder pad and a second solder pad on its upper surface.

[0070] Specifically, the heat sink is a key component for dissipating heat from edge laser chips. During laser operation, the chip generates a significant amount of heat. If this heat is not dissipated promptly, the chip temperature will rise, affecting laser performance and potentially even damaging the chip. The heat sink, through its large surface area and excellent thermal conductivity, quickly transfers the heat generated by the chip to the surrounding environment, dissipating heat and ensuring the chip operates within the appropriate temperature range.

[0071] The top surface of the heat sink is equipped with a first solder pad and a second solder pad, which are used to connect to the positive and negative electrodes of the edge laser chip, respectively. The design of the solder pads must consider good bonding performance with the chip electrodes and gold wires to ensure reliable and stable electrical connections. Furthermore, the material and surface treatment of the solder pads also affect the soldering quality and heat dissipation effect.

[0072] The heat sink also provides mechanical support for the edge laser chip and other components, making the entire package structure more stable. Its shape and size need to be designed to take into account the coordination with other components and the overall layout of the package to meet the needs of different application scenarios.

[0073] The cover 1 is located above the heat sink, is sealed with the heat sink, and wraps the edge laser chip and the gold wire; the cover is at least partially transparent to allow the laser to be emitted.

[0074] Specifically, the cover is located above the heat sink and sealed to the heat sink, enclosing the edge laser chip and gold wire. It effectively prevents external dust, moisture, chemicals, etc. from corroding and contaminating the chip and gold wire, protecting their normal working environment and extending the service life of the laser.

[0075] The cover must be at least partially transparent to ensure smooth laser emission from the chip. The material of the transparent portion must have good optical transparency and minimal absorption and scattering of the laser light to minimize laser energy loss. Furthermore, the surface quality and optical flatness of the transparent portion will affect the quality of laser emission and require meticulous processing and treatment.

[0076] The seal between the housing and the heat sink is crucial. It prevents gases and impurities from the external environment from entering the package, maintaining a clean and stable interior. Common sealing methods include welding and gluing. The sealing material must possess excellent sealing properties and temperature resistance to ensure a good seal under various operating conditions.

[0077] In some embodiments, the cover is made of at least two materials, including at least one of copper, aluminum, and ceramic, to improve the heat dissipation effect. Copper has a very high thermal conductivity, and at room temperature, its thermal conductivity is about 400W / (m·K). This means that it can conduct heat quickly and quickly transfer the heat generated by the edge laser chip. In addition, copper has good processing performance and can be made into cover parts of various shapes through various processes such as casting, forging, and machining to meet different packaging requirements.

[0078] Aluminum is also a commonly used heat dissipation material, with a thermal conductivity of approximately 200W / (m·K). Although its thermal conductivity is lower than that of copper, aluminum has the advantages of low density and light weight, which reduces the overall weight of the package. For some weight-sensitive applications, such as aerospace, aluminum is a good choice. In addition, aluminum is relatively low in cost and has good corrosion resistance, which can protect the internal chips and gold wires to a certain extent.

[0079] Ceramic materials possess many unique properties. Some, such as aluminum nitride (AlN) and silicon carbide (SiC), have high thermal conductivity, reaching 170-220 W / (m·K) and 270-490 W / (m·K), respectively. Ceramics also offer excellent insulation properties, effectively preventing electrical signal interference, and possess high temperature resistance and chemical stability, enabling their use in harsh environments.

[0080] Advantages of multi-material combination

[0081] Synergistic heat dissipation: Different materials have different properties, such as thermal conductivity and coefficient of thermal expansion. By combining at least two materials, their respective strengths can be leveraged to achieve better heat dissipation. For example, copper or aluminum can be used for areas with faster heat conduction, while ceramic can be used for areas requiring insulation and high-temperature resistance. This allows heat to be quickly transferred to the outside through the highly conductive copper or aluminum, while the ceramic maintains the electrical performance and stability of the package.

[0082] Optimizing the structure: Combining multiple materials can optimize the housing's structure. For example, a layered structure can be employed, combining materials with different properties to improve heat dissipation efficiency and overall package performance. The placement of different materials can also be rationally arranged based on the chip's heat generation characteristics and heat flow distribution, allowing for more efficient heat dissipation.

[0083] Taking into account both light and heat dissipation: Light can be emitted through the transparent area, and high thermal conductivity materials are placed outside the optical path to take into account both laser penetration and heat dissipation requirements.

[0084] Specific application examples

[0085] Copper-ceramic combination: Copper can be used as the outer layer of the housing, leveraging its high thermal conductivity to quickly transfer heat to the outside world. Ceramic, on the other hand, serves as the inner layer, contacting the chip and gold wires to provide insulation protection. This combination ensures effective heat dissipation while avoiding the risk of electrical short circuits.

[0086] Aluminum-ceramic combination: In some applications where weight is a concern, aluminum can be used as the main material for the housing to reduce weight. At the same time, ceramic materials are used in key areas, such as those near the chip, to improve local heat dissipation and insulation performance.

[0087] By making the cover body composed of at least two materials, including one of copper, aluminum, and ceramic, the advantages of these materials can be fully utilized, the heat dissipation effect of the edge laser package can be improved, and the performance and stability of the laser can be guaranteed.

[0088] In some embodiments, the volume of the enclosed space formed by the cover and the heat sink is positively correlated with the power of the edge laser chip. The higher the chip power, the more heat it generates during operation. A larger enclosed space can provide more sufficient air convection space, which is conducive to the transfer of heat to the heat sink and the cover surface through natural convection or forced convection of the air, and then dissipated into the surrounding environment. For example, for high-power edge laser chips, when the volume of the enclosed space is larger, the circulation process of air rising when heated and falling when cooled in the space is smoother, which can more effectively carry away the heat emitted by the chip and prevent the chip from overheating and causing performance degradation or damage.

[0089] The high-intensity laser emitted by high-power edge laser chips can cause optical interference such as thermal lensing in the surrounding air. Properly increasing the volume of the enclosed space can reduce uneven heating of the air, minimize optical interference, and maintain laser beam quality and transmission performance. Furthermore, a larger space helps minimize the interaction of the laser with impurities, water vapor, and other factors during reflection and scattering within the cavity, thus avoiding laser loss and beam distortion caused by these factors.

[0090] As chip power increases, the amount of heat generated per unit time increases significantly. If the enclosure is too small, heat can accumulate quickly within the confined space, causing the temperature to rise sharply. Larger enclosures, on the other hand, can accommodate more heat, slowing the temperature rise and providing the cooling system with more time to dissipate the heat, thus maintaining the chip within the appropriate operating temperature range.

[0091] In summary, in order to meet the heat dissipation requirements of high-power edge laser chips, maintain good optical performance, and prevent heat accumulation from damaging the chip and packaging structure, the volume of the enclosed space formed by the cover and the heat sink needs to be positively correlated with the power of the edge laser chip to ensure that the edge laser can operate stably and efficiently at different powers.

[0092] In some embodiments, Figure 3 As shown, there is a groove 15 inside the cover body for passing the gold wire to fix the upper surface of the edge laser chip. The groove 15 is opened on the inner surface 13 of the cover body. The outer surface of the cover body is a smooth surface. As a key component connecting the positive electrode of the edge laser chip and the first solder pad of the heat sink, the accuracy of its fixation and direction is crucial. The groove in the cover body can provide a clear path for the gold wire so that it will not shake or misalign when passing through, ensuring the stability and reliability of the gold wire connection. The groove plays a certain supporting and restraining role on the gold wire, preventing the gold wire from being deformed or broken due to external forces during the packaging process or long-term use, ensuring the smooth electrical connection, and thus enabling the edge laser chip to obtain a stable current supply and emit laser normally.

[0093] Edge laser chips generate heat and vibration during operation. If the chip's top surface is not effectively secured, it can shift, affecting the laser's emission direction and beam quality. It can even loosen the connection between the chip and the heat sink or other components, reducing laser performance and reliability. By passing a gold wire through a groove and applying a certain amount of tension to the chip's top surface, the chip can be securely fixed to the heat sink, limiting its displacement and ensuring stability during operation. This fixing method is not only simple and effective, but also does not negatively impact chip performance and facilitates the packaging process.

[0094] The presence of the grooves allows for more regular gold wire routing, optimizing the overall package layout. This prevents interference between the gold wires and other components, reduces internal package space, and allows for more efficient use of the space between the housing and the heat sink. This regular gold wire routing also facilitates subsequent inspection and maintenance, improving the package's manufacturability and maintainability.

[0095] When the chip's top surface is effectively fixed, the contact between the chip and the heat sink becomes closer, facilitating heat transfer from the chip to the heat sink and enhancing the heat dissipation effect. Good heat dissipation is crucial to the performance and lifespan of edge laser chips. Fixing the chip with grooves and gold wires indirectly improves the heat dissipation performance of the entire package, helping the edge laser maintain stable performance over long periods of operation.

[0096] The chip's top surface is in contact with the cover, allowing the heat generated by the chip to dissipate not only through the heat sink but also directly outward from the cover. The contact area between the cover and the chip is made of a highly thermally conductive material, effectively improving heat dissipation and enabling rapid heat dissipation from both the top and bottom surfaces of the chip.

[0097] The design of setting grooves in the cover to allow the gold wire to pass through and fix the upper surface of the edge laser chip plays an important role in ensuring the stability of electrical connections, fixing the chip position, optimizing the packaging structure and enhancing the heat dissipation effect. It is an indispensable part of the edge laser package.

[0098] In some embodiments, the minimum distance between the cover and the second pad is less than 1 mm. During the heat transfer process, distance is one of the key factors affecting the heat conduction speed. When the distance between the cover and the second pad is less than 1 mm, the thermal resistance between the two will be significantly reduced. The heat generated by the edge laser chip during operation will first be conducted to the second pad. Due to the shortened distance, the heat can be transferred from the second pad to the cover more quickly. The cover usually has a larger surface area and can dissipate heat more effectively to the surrounding environment, thereby improving the heat dissipation performance of the entire package, ensuring that the edge laser chip works stably at an appropriate temperature, and avoiding performance degradation or shortened life due to overheating.

[0099] Electromagnetic interference is a common problem in electronic devices, and edge lasers are no exception. The second pad generates a certain electromagnetic field during operation, and the cover acts as an electromagnetic shield. When the distance between the cover and the second pad is small, the electromagnetic field generated by the second pad can be better shielded inside the cover, reducing electromagnetic radiation interference from the outside world. It also prevents external electromagnetic interference from entering the package and affecting the normal operation of the edge laser chip, thereby improving the electromagnetic compatibility of the edge laser.

[0100] With the trend toward miniaturization of modern electronic devices, the size of edge laser packages needs to be minimized. Keeping the minimum distance between the cover and the second pad to less than 1mm makes the entire package more compact. This not only helps reduce the overall size of the edge laser, meeting space-critical applications such as integrated optical systems and small optical communication equipment, but also reduces the amount of packaging material used, lowering costs.

[0101] A smaller distance enhances the mechanical connection stability between the cover and the second pad. During the packaging process, the two interact more closely, providing better resistance to external mechanical stresses such as vibration and impact. This helps ensure the integrity of the package structure, reduces problems such as wire breakage and chip displacement caused by mechanical stress, and improves the reliability and stability of the edge laser, extending its service life.

[0102] In summary, stipulating that the minimum distance between the cover and the second pad is less than 1 mm is the result of comprehensive consideration of multiple factors such as heat dissipation, electromagnetic shielding, structural compactness and packaging stability, and is of great significance for improving the performance and reliability of edge lasers.

[0103] In some embodiments, the gold wire is electrically connected to the first pad and the other electrode of the edge laser chip by gold ball bonding or ultrasonic welding.

[0104] Gold wire ball bonding is a hot-pressed ultrasonic welding technique. First, the end of a gold wire is formed into a ball using an electrical discharge. This ball is then placed on the electrode to be bonded (such as the positive electrode of an edge laser chip). By applying a certain amount of pressure, heat, and ultrasonic vibration, the metal atoms on the gold ball and the electrode surface diffuse into each other, forming a strong metallurgical bond and achieving an electrical connection. The gold wire is then pulled onto the first pad and connected to it using the same principle.

[0105] The contact area between the gold ball formed by gold wire ball welding and the electrode is large, which can provide lower contact resistance, ensure stable current transmission, reduce heat and energy loss caused by excessive resistance, and improve the working efficiency and stability of the edge laser.

[0106] Gold wire ball bonding technology has a long history of application in semiconductor packaging. The process is relatively mature, with standardized equipment and operating procedures, ensuring high welding quality and consistency, making it suitable for large-scale production. The ability to precisely control the size and position of the gold balls meets the delicate packaging requirements of edge lasers, which require high welding precision.

[0107] Ultrasonic welding uses the energy generated by ultrasonic vibrations to plastically deform the metal between the gold wire and the electrode surface, breaking down the oxide layer on the metal surface and allowing pure metal atoms to come into contact and form a bond. During the welding process, ultrasonic vibrations generate high-frequency friction at the contact interface, converting mechanical energy into heat energy, promoting the diffusion and bonding of metal atoms.

[0108] Advantages of ultrasonic welding

[0109] Low-temperature welding: Ultrasonic welding does not require the high temperatures required for gold wire ball welding, which is very beneficial for temperature-sensitive devices such as edge laser chips. Lower welding temperatures can reduce the impact on the chip's internal structure and performance, reduce the risk of chip damage due to thermal stress, and improve chip yield and reliability.

[0110] Fast welding speed: Ultrasonic vibration can quickly make metal materials reach the welding state. The welding process takes a shorter time, which improves production efficiency and is suitable for large-scale industrial production.

[0111] Wide range of applicable materials: It can be used for welding between different metal materials. For the various metal material combinations that may be involved in edge laser packaging, ultrasonic welding can achieve good electrical connection.

[0112] In summary, gold wire ball bonding and ultrasonic welding each have their advantages in edge laser packaging. The specific welding method to be selected should be considered based on the specific design requirements of the edge laser, production process, cost, and other factors. Both welding methods can provide a reliable electrical connection between the gold wire and the first bonding pad and the positive electrode of the edge laser chip, ensuring the normal operation of the edge laser.

[0113] In some embodiments, the second soldering pad and the first soldering pad of the heat sink are both provided with a plating layer to improve soldering quality and electrical connection performance.

[0114] Improve welding quality

[0115] Preventing Oxidation: Solder pads are typically made of metal, which is easily oxidized in air. Once an oxide layer forms on the pad surface, it hinders the bonding of the solder to the pad metal during soldering, resulting in weak solder joints and problems such as cold or false solder joints. Plating acts as a barrier, effectively isolating the pad from air and preventing oxidation. For example, common plating materials such as gold and nickel have excellent chemical stability, maintaining a clean and solderable pad surface for extended periods. This ensures that the solder fully fuses with the pad during soldering, forming a secure joint.

[0116] Improved Wettability: During the soldering process, the wettability of the solder on the pad surface is a key factor influencing soldering quality. Good wettability means that the solder spreads evenly across the pad surface, making full contact with the pad and thus forming a good metallurgical bond. The surface properties of the coating material can improve solder wettability. For example, gold plating has excellent wettability, making it easier for solder to spread across the surface, reducing surface tension at the solder interface and improving soldering reliability and stability.

[0117] Enhanced welding strength: A suitable coating can form a good metallurgical bond with the solder and pad metal, enhancing the strength of the welded joint. During the operation of edge lasers, they are affected by various factors such as vibration and thermal cycling. If the welding strength is insufficient, it can easily lead to loosening or fracture of the welded joint, affecting the performance and reliability of the laser. The coating can improve the mechanical properties of the welded joint, enabling it to withstand certain external forces and ensuring the stable operation of the edge laser in complex environments.

[0118] Optimize electrical connection performance

[0119] Reducing contact resistance: Electrical connection performance is primarily determined by the magnitude of contact resistance. Excessive contact resistance not only increases energy loss but also generates excessive heat, impacting the efficiency and stability of the edge laser. Plating materials typically have excellent electrical conductivity, which can reduce the contact resistance between the pad and the gold wire or other connecting components. For example, gold is an excellent conductor of electricity. Using gold plating allows current to flow more smoothly through the connection, reducing heat generated by resistance and improving the efficiency of the electrical connection.

[0120] Improved conductivity uniformity: The coating can make the pad surface smoother and more uniform, thereby improving conductivity uniformity. When an edge laser is operating, the current needs to be evenly distributed across the pad. If the pad surface is uneven or has impurities, this will lead to uneven current distribution and affect the laser's performance. The coating can improve the microstructure of the pad surface, allowing for uniform current conduction and ensuring consistent performance across all parts of the edge laser.

[0121] Reduce electrochemical corrosion: When dissimilar metals come into contact, electrochemical corrosion is more likely to occur due to potential differences. Heat sink pads and connecting components such as gold wires may be made of different metals. Plating can prevent these dissimilar metals from coming into direct contact, reducing the risk of electrochemical corrosion. This ensures long-term electrical connection stability and extends the life of the edge laser.

[0122] In summary, providing a coating on the second pad and the first pad of the heat sink is an important measure to improve the welding quality and electrical connection performance of the edge laser package, which can ensure the stable and efficient operation of the edge laser.

[0123] In some embodiments, Figure 4 and Figure 6 As shown, the heat sink includes a substrate 5, a first positive electrode 8, a first negative electrode 6, a second positive electrode 9, a second negative electrode 7, and a filling hole 10;

[0124] The first positive electrode and the first negative electrode are located on the upper surface of the substrate;

[0125] The second positive electrode and the second negative electrode are located on the lower surface of the substrate;

[0126] The substrate has the filling hole inside;

[0127] Conductive metal 11 is provided in the filling hole for connecting the first positive electrode and the second positive electrode, and the first negative electrode and the second negative electrode.

[0128] Specifically, the substrate 5 serves as the heat sink's underlying support structure, providing physical support and a mounting platform for other components. It must possess a certain level of mechanical strength and stability to ensure the entire heat sink does not deform or damage during the packaging process and subsequent use. Furthermore, the substrate must exhibit good thermal conductivity to effectively conduct heat generated by the edge laser chip.

[0129] First positive electrode 6 and first negative electrode 7: Located on the top surface of the substrate, they are primarily used to connect to the positive and negative electrodes of the edge laser chip. Using gold wire or other connection methods, the chip electrodes are connected to the electrodes on the top surface of the heat sink, providing power input and current flow for the chip to ensure normal operation.

[0130] The second positive electrode 8 and the second negative electrode 9 are located on the bottom surface of the substrate. These electrodes facilitate connection to external circuits. In practical applications, the edge laser package needs to be integrated with other electronic devices or systems. The bottom surface electrodes serve as interfaces to achieve electrical connection with external power and control circuits, enabling the entire laser system to work together.

[0131] Filled vias 10 are provided within the substrate to provide space for conductive metal to fill, thereby achieving electrical connectivity between the electrodes on the upper and lower surfaces. The design of the filled vias requires precise control of their diameter, depth, and position to ensure that the conductive metal can accurately fill them and maintain good contact with the electrodes on the upper and lower surfaces.

[0132] The conductive metal 11 (e.g., copper) filled in the via 10 acts as a bridge, connecting the first positive electrode and the first negative electrode on the upper surface to the second positive electrode and the second negative electrode on the lower surface, respectively. This allows current to flow from the external circuit through the lower surface electrodes, the conductive metal, the upper surface electrodes, and ultimately to the edge laser chip, forming a complete current loop.

[0133] The advantages of this structural design

[0134] Optimized electrical connections: Connecting the upper and lower surface electrodes through vias and conductive metal eliminates the need for complex external wiring, reduces the effects of resistance and inductance, and improves the efficiency and stability of current transmission. This internal connection method also effectively reduces electromagnetic interference, ensuring the accuracy and reliability of the edge laser signal during operation.

[0135] Improved heat dissipation: One of the primary functions of a heat sink is to dissipate heat. As a key component in heat conduction, the substrate's structural design affects heat dissipation. The presence of vias increases the thermal conductivity path within the substrate, allowing heat to be transferred more quickly from the chip to various components of the heat sink and then dissipated into the surrounding environment. Furthermore, conductive metals also have certain thermal conductivity properties, which further improves heat dissipation efficiency.

[0136] Compactness and Integration of the Package: This structural design integrates the heat sink's electrical connections and heat dissipation functions into a relatively compact structure, reducing the package size and footprint. This is of great significance to the miniaturization and integration of modern electronic devices, and can meet the package size requirements of edge lasers in different application scenarios.

[0137] In summary, this structural design of the heat sink has significant advantages in terms of electrical connection, heat dissipation performance and packaging integration, which can improve the performance and reliability of the edge laser and meet the needs of practical applications.

[0138] In some embodiments, Figure 5 As shown, a solder region 12 is provided at the center of the first negative electrode, and the size of the solder region is larger than the edge laser chip.

[0139] Enhanced mechanical stability: A larger solder area provides broader and more stable support for the edge laser chip. Edge laser chips may be subject to various external forces during operation, such as vibration and impact. When the solder area is larger than the chip, the contact area between the chip and the first negative electrode increases, allowing the chip to be more firmly fixed to the electrode after soldering, reducing the risk of chip displacement or detachment due to external forces. This enhances the mechanical stability of the entire package structure and ensures the normal operation of the edge laser even in complex environments.

[0140] Optimizing heat dissipation: Heat generated by the chip is primarily transferred through contact with the heat sink. The larger solder area serves as the connection between the chip and the first negative electrode, and its larger size provides a larger heat transfer surface. This facilitates faster and more even transfer of heat generated by the chip to the first negative electrode, where it is then dissipated to the surrounding environment through the rest of the heat sink. Good heat dissipation is crucial for maintaining chip performance and extending its lifespan, preventing chip degradation or even damage due to overheating.

[0141] Improved Soldering Reliability: A larger solder area provides greater margin for error during soldering. During the soldering process, errors may occur due to factors such as process precision. A larger solder area can compensate for these errors to a certain extent, ensuring a good solder connection between the chip and the first negative electrode and reducing the likelihood of soldering defects such as cold joints and desoldering. Furthermore, a larger solder volume helps improve the strength and durability of the solder joint, ensuring long-term reliability of the electrical connection.

[0142] Facilitates chip installation and positioning: When the solder area is larger than the edge of the laser chip, it is easier for the operator to accurately place the chip in the appropriate position during chip installation, improving the efficiency and accuracy of chip installation. The edge of the chip can be clearly compared with the edge of the solder area, serving as a reference for installation, reducing performance problems caused by inaccurate installation, such as poor contact between the chip and the electrode.

[0143] Accommodating Chip Size Variations: During edge laser production, chips of varying sizes may be used. The larger solder area can accommodate a variety of chip sizes, increasing the versatility and flexibility of the heat sink design. This eliminates the need to design a separate heat sink structure for each chip size, reducing production costs and R&D cycles while improving production efficiency.

[0144] In summary, the design in which the solder area at the center of the first negative electrode is larger than the edge laser chip has significant advantages in terms of mechanical stability, heat dissipation, welding reliability, chip installation, and versatility, and plays an important role in improving the performance and reliability of the edge laser.

[0145] In some embodiments, the diameter of the filling hole is [0.05 mm, 0.2 mm].

[0146] Electrical performance

[0147] Conductivity: Conductive metal is filled into the via to connect the electrodes on the upper and lower surfaces of the heat sink, forming a current path. Vias with too small a diameter (close to the lower limit of 0.05mm) can accommodate less conductive metal, resulting in increased resistance, affecting current transmission efficiency and increasing energy loss. However, within the appropriate diameter range, sufficient conductive metal can be ensured, reducing resistance and allowing current to flow stably and efficiently, meeting the operating requirements of the edge laser chip. For example, if the via diameter is too small, current transmission may be poor, resulting in unstable chip operation and affecting the power and quality of the output laser.

[0148] Electromagnetic compatibility: A suitable via diameter helps reduce electromagnetic interference. Excessively large via diameters (approaching the upper limit of 0.2mm) can generate a large electromagnetic field around the via, affecting the electromagnetic environment within the heat sink and surrounding circuits, and potentially interfering with the normal operation of the edge laser chip. Within the specified diameter range, the distribution of the electromagnetic field can be effectively controlled while ensuring electrical conductivity, improving the electromagnetic compatibility of the entire package.

[0149] Thermal performance

[0150] Thermal Conductivity: The conductive metal within the via also participates in the heat conduction process. Larger diameter vias (approaching the upper limit of 0.2mm) contain more conductive metal, which facilitates faster heat transfer from the upper to lower surfaces of the heat sink, enhancing the heat sink's heat dissipation capacity. This is crucial for dissipating heat generated by the edge laser chip and maintaining the chip at a suitable operating temperature. However, an excessively large diameter may also affect the mechanical strength of the substrate, requiring careful consideration.

[0151] Thermal stress control: Edge lasers experience thermal expansion and contraction during operation. An inappropriate via diameter can lead to concentrated thermal stress. Small via diameters (close to the lower limit of 0.05mm) can cause significant stress at the junction between the via and the conductive metal during thermal expansion and contraction, leading to cracking or loosening, which can affect thermal conduction and electrical connection stability. An appropriate diameter range can effectively control thermal stress and ensure heat sink reliability.

[0152] Manufacturing process

[0153] Processing feasibility: From a manufacturing perspective, if the via diameter is too small (approaching the lower limit of 0.05mm), the processing difficulty will increase significantly. For example, during the drilling process, problems such as drill wear and difficulty in ensuring drilling accuracy are prone to occur, resulting in reduced production efficiency and increased costs. On the other hand, if the diameter is too large (approaching the upper limit of 0.2mm), although processing is relatively easy, it may cause significant damage to the structural integrity of the substrate, affecting the overall performance of the heat sink. Therefore, the diameter range of [0.05mm, 0.2mm] can meet the performance requirements of the heat sink while ensuring a certain degree of processing feasibility.

[0154] Compatibility with other components: The diameter of the filling hole must be coordinated with other components of the heat sink, such as the electrodes and conductive metal. A suitable diameter ensures good contact and connection between the conductive metal and the electrodes, guaranteeing stable electrical and mechanical properties. An inappropriate diameter may result in insufficient conductive metal filling or poor contact with the electrodes, affecting the proper functioning of the heat sink.

[0155] The diameter of the filling hole is set in the range of [0.05mm, 0.2mm], which is the result of comprehensive consideration of multiple factors such as electrical performance, thermal performance and manufacturing process. It is of great significance to ensure the performance and reliability of the heat sink in the edge laser package.

[0156] This specification also provides a method for manufacturing a laser package, comprising the following steps:

[0157] S1: Mount one electrode of the edge laser chip to the first pad of the heat sink solder area through AuSn eutectic or silver glue;

[0158] S2: Connect the other pole on the upper surface of the laser and the second pad on the upper surface of the heat sink through a gold wire;

[0159] S3: Place the heat sink with the laser mounted in an environment filled with nitrogen (N2) or clean dry air (CDA);

[0160] S4: In an environment filled with nitrogen (N2) or clean dry air (CDA), mount the cover to the upper surface of the heat sink by SMT or thermosetting adhesive to seal the laser and gold wire.

[0161] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0162] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An edge laser package, characterized in that: include: Edge laser chip, used for emitting laser; Gold thread; a heat sink having a first solder pad and a second solder pad on an upper surface thereof; One electrode of the edge laser chip is fixed to the second pad, and the other electrode of the edge laser chip is connected to the first pad via the gold wire; The cover is located above the heat sink, is sealed with the heat sink, and wraps the edge laser chip and the gold wire; the cover is at least partially transparent to allow the laser to be emitted.

2. The edge laser package according to claim 1, characterized in that: The cover is made of at least two materials, including at least one of copper, aluminum and ceramic, so as to improve the heat dissipation effect.

3. The edge laser package according to claim 1, characterized in that: The volume of the enclosed space formed by the cover and the heat sink is positively correlated with the power of the edge laser chip.

4. The edge laser package according to claim 1, characterized in that: The cover body is provided with a groove for passing a gold wire, thereby fixing the upper surface of the edge laser chip.

5. The edge laser package according to claim 4, characterized in that: The minimum distance between the cover and the second pad is less than 1 mm.

6. The edge laser package according to claim 1, characterized in that: The gold wire is electrically connected to the first pad and the other electrode of the edge laser chip by gold wire ball bonding or ultrasonic welding.

7. The edge laser package according to claim 1, characterized in that: The second soldering pad and the first soldering pad of the heat sink are both provided with a plating layer to improve soldering quality and electrical connection performance.

8. The edge laser package according to claim 1, characterized in that: The heat sink includes a substrate, a first positive electrode, a first negative electrode, a second positive electrode, a second negative electrode, and a filling hole; The first positive electrode and the first negative electrode are located on the upper surface of the substrate; The second positive electrode and the second negative electrode are located on the lower surface of the substrate; The substrate has the filling hole inside; Conductive metal is contained in the filling hole and is used to connect the first positive electrode and the second positive electrode, and the first negative electrode and the second negative electrode.

9. The edge laser package according to claim 8, characterized in that: A solder region is provided at the center of the first negative electrode, and a size of the solder region is larger than that of the edge laser chip.

10. The edge laser package according to claim 8, characterized in that: The diameter of the filling hole is [0.05mm, 0.2mm].

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