A laser device convenient for patch packaging

Abstract

The utility model discloses a kind of laser devices convenient to patch package, including support, laser chip, metal pipe cap, the support includes concave table, metallized pad and annular step part, metal heat sink is fixedly embedded in the concave table, the laser chip is fixed on the metal heat sink upper surface by eutectic solder, the metal pipe cap is the tubular structure of one end opening one end airtight, the edge of the opening end of the metal pipe cap is sealed and fixed with the annular step part, the problems such as high cost, low production efficiency, poor fault tolerance, heavy weight of traditional TO packaging equipment are solved by structural innovation, under the premise of guaranteeing the performance of laser device, production economy and process adaptability are significantly improved.

Description

Technical Field

[0001] This utility model relates to the field of laser device packaging technology, and in particular to a laser device that is easy to surface mount package. Background Technology

[0002] Transistor Outline (TO) packaging is a traditional packaging method, typically cylindrical in shape, and commonly used in devices such as semiconductor lasers. It offers excellent thermal conductivity, with the metal casing effectively dissipating heat generated during laser operation, making it suitable for applications requiring good heat dissipation. The TO packaging process involves: first, cleaning and removing oil and oxide layers from the metal base; then, applying thermally conductive insulating adhesive to the die area of ​​the base; precisely placing the LED or laser die on the adhesive-coated area and curing at 150-200℃ for 1-2 hours to complete die bonding; subsequently, using 25-50μm gold / copper wires, ultrasonic bonding technology is used to connect the die electrodes to the base leads to form an electrical circuit; next, the metal casing with a transparent glass window is fastened to the base, achieving a seal through laser or resistance welding; finally, helium mass spectrometry leak detection is used to test the hermeticity of the package, simultaneously testing electrical and optical properties such as forward voltage and luminous flux; qualified products are marked on the surface and sorted and packaged according to parameters, completing the final packaging process. TO packaging equipment is highly specialized and costly, requiring specialized equipment such as laser welding machines and helium mass spectrometer leak detectors, with the cost of a single unit exceeding one million. Its processes are mostly "semi-automated," with manual assistance required for shell welding, resulting in low production efficiency, unsuitability for mass production, and high depreciation costs per unit of equipment. It has a low fault tolerance rate; a single mistake can lead to scrapping. If the airtightness is found to be substandard after shell welding, it cannot be disassembled and reworked, rendering the entire product unusable. If the wire bonding breaks, the shell must be removed and rebonded, a cumbersome process that can easily damage the die. Utility Model Content

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, this utility model provides a laser device that is easy to be surface-mount packaged, which solves the technical problems of existing TO packaged lasers, such as the high equipment specialization required, high production cost, high production defect rate, and high product weight, which leads to low production efficiency due to semi-automated production.

[0004] To solve the above-mentioned technical problems, this utility model provides a laser device that is easy to surface mount, including a bracket, a laser chip, and a metal cap. The bracket includes a recess, a metallized pad, and an annular step. A metal heat sink is fixedly embedded in the recess. The laser chip is fixed to the upper surface of the metal heat sink by eutectic solder. The metal cap is a cylindrical structure with one open end and one closed end. The edge of the open end of the metal cap is sealed and fixed to the annular step.

[0005] Preferably, the sealed end of the metal cap is provided with an optical window, through which the light emitted by the laser chip passes.

[0006] Preferably, the N-electrode and P-electrode of the laser chip are electrically connected to the two metallized pads one-to-one via bonding wires.

[0007] Preferably, the metallized pad has a copper-nickel-gold three-layer plating structure, and the metallized pad is connected to the external pins through the circuit wiring inside the bracket.

[0008] Preferably, the optical window is located at the center of the sealed end of the metal cap, and the diameter of the optical window is smaller than the diameter of the cylindrical shape of the metal cap.

[0009] Preferably, the optical window is made of sapphire glass or quartz glass, and the optical window is sealed and fixed to the sealed end of the metal cap by low melting point glass solder.

[0010] Preferably, the metal cap is a Kovar alloy or stainless steel stamped structure.

[0011] Preferably, the edge of the open end of the metal cap has an extension that extends radially outward along the body of the metal cap, and the extension abuts against and is fixed to the annular step portion.

[0012] Preferably, the extension portion and the annular step portion are bonded and fixed with a modified epoxy adhesive, and the modified epoxy adhesive fills the gap between the metal cap and the annular step portion to form a continuous sealing ring.

[0013] Preferably, the sidewall of the recessed platform is configured as an annular inclined surface with a certain tilt angle, which has a reflective function.

[0014] Preferably, the support is made of poly(phthalamide) (PPA).

[0015] Preferably, the metal heat sink is made of copper-tungsten alloy or copper-molybdenum alloy, the thickness of the metal heat sink is 0.5-1.2mm, and the lower surface of the metal heat sink is injection molded integrally with the bracket.

[0016] Preferably, the bonding wire has a diameter of 20-50 μm, is made of gold or copper wire, and its two ends are connected to the laser chip electrode and the metallized pad respectively by ultrasonic bonding process.

[0017] Preferably, the light-incident surface of the optical window is provided with an anti-reflection film, and the wavelength of the anti-reflection film is adapted to the emission wavelength of the laser chip.

[0018] Preferably, the external pins of the bracket are gold-plated copper pins, which are injection molded integrally with the bracket, and the exposed portion of the external pins has a bending structure with a bending angle of 90°.

[0019] Compared with the prior art, the beneficial effects obtained by this utility model are:

[0020] This utility model discloses a laser device that is easy to surface mount package, including a bracket, a laser chip, and a metal cap. The bracket includes a recess, a metallized pad, and an annular step. A metal heat sink is fixedly embedded in the recess. The laser chip is fixed to the upper surface of the metal heat sink by eutectic solder. The metal cap is a cylindrical structure with one open end and one closed end. The edge of the open end of the metal cap is sealed and fixed to the annular step. Through structural innovation, this invention solves the problems of high cost, low production efficiency, poor fault tolerance, and heavy weight of traditional TO packaging equipment. While ensuring the performance of the laser device, it significantly improves the production economy and process adaptability.

[0021] By employing an adhesive bonding structure between the bracket and the metal cap, equipment costs are reduced and versatility is improved. The extension of the metal cap and the annular step of the bracket are bonded and fixed with modified epoxy adhesive, replacing the laser welding sealing method of TO packaging. This eliminates the need to purchase a million-dollar laser welding machine and a helium mass spectrometer leak detector. At the same time, the injection molding of the bracket and the electroplating process of the metallized pads are directly compatible with general equipment such as die bonders and bonding machines in SMT production lines, significantly reducing dependence on equipment specialization and achieving a cost reduction of more than 60%.

[0022] By employing a standardized positioning structure and integrated injection-molded pins, production efficiency is improved and fully automated production is achieved. The recessed platform and annular step of the bracket are formed in one injection molding process, creating a precise automated positioning reference. The external pins are gold-plated copper pins with 90° bends, integrally injection molded with the bracket, eliminating the need for subsequent molding processes. This structure enables the entire assembly process (die bonding, bonding, and cap bonding) to be fully automated using SMT equipment, replacing the manual positioning step required for TO packaging, significantly improving production efficiency and adapting to large-scale mass production.

[0023] The reversible sealing structure using modified epoxy adhesive improves fault tolerance and reduces defect rate. The metal cap and the bracket form a detachable sealed connection through modified epoxy adhesive. Compared with the irreversible welding structure of TO packaging, when the bonding wire is broken or the electrical performance is unqualified, the cap can be disassembled non-destructively by heating to soften the adhesive for rework. After repair, the adhesive can be reapplied and bonded to form an effective seal. This solves the problem of TO packaging where a single mistake results in scrap, and reduces the rework rate of defective products by more than 80%.

[0024] The composite structure of non-metallic support and thin-walled metal cap achieves lightweight design and optimized surface mount compatibility. Using PPA material (density approximately 1.4 g / cm³) as the main support and a thin-walled (wall thickness ≤ 0.3 mm) metal cap, the overall weight is reduced by 40%-50% compared to all-metal TO packages (density approximately 7.8 g / cm³). The 90° bend design of the external leads directly adapts to surface mount processes, replacing the through-hole mounting method of TO packages, and improving assembly efficiency by more than 50%.

[0025] The design integrates metal heat sink mounting with optical structure to achieve a balance between performance stability and process flexibility. The recessed platform is equipped with a metal heat sink, which is fixed with the laser chip by eutectic bonding to ensure that the heat dissipation performance is no worse than that of TO package. At the same time, the PPA bracket can be flexibly integrated with the recessed platform reflective bevel, positioning holes and other structures through injection molding to adapt to the design requirements of chips with different power. Compared with the standardized metal shell of TO package, the design iteration cycle is shortened by more than 30%, which balances performance and flexibility. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0027] Figure 1 This diagram illustrates a laser device that is easy to surface mount and package according to the present invention.

[0028] Figure 2 This invention provides a schematic diagram of die bonding wires for a laser device that is easy to surface mount package.

[0029] Figure 3 This invention provides a cross-sectional view of a support for a laser device that is easy to surface mount.

[0030] Figure 4 This is a top view of a laser device that is easy to surface mount and package according to the present invention.

[0031] Figure 5 This invention relates to a metal cap for a laser device that is easy to surface mount.

[0032] Reference numerals: 1-bracket; 11-recess; 12-metallized pad; 13-annular step; 2-laser chip; 3-metal cap; 31-optical window; 32-extension. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a laser device that is easy to surface mount package. Its structural design takes into account both packaging reliability and surface mount process compatibility. The specific structure is as follows:

[0036] The laser device includes a bracket 1, a laser chip 2, and a metal cap 3. The bracket 1 is injection molded from polyphthalamide (PPA) and has a flat overall structure to accommodate surface mount applications. The top of the bracket 1 has a recess 11, two metallized pads 12, and an annular step 13. The recess 11 is located in the central area of ​​the bracket 1, and its sidewall is an annular inclined surface with a certain angle. This inclined surface is mirror-finished to form a reflective surface, which reflects the lateral light emitted by the laser chip 2 forward, improving light output efficiency.

[0037] A metal heat sink is fixedly embedded within the recessed platform 11. The metal heat sink and the support 1 are injection molded as a single unit. The laser chip 2 is fixed to the upper surface of the metal heat sink using eutectic solder, achieving good heat conduction. The N-electrode and P-electrode of the laser chip 2 are electrically connected to the two metallized pads 12 one-to-one via bonding wires. The bonding wires are made of gold or copper wire and are connected using an ultrasonic bonding process.

[0038] The metallized pad 12 has a copper-nickel-gold three-layer plating structure. It is connected to the external pins located at the bottom of the bracket 1 through the circuit wiring inside the bracket 1. The external pins are gold-plated copper pins and are injection molded as one piece with the bracket 1. Its exposed part has a 90° bending structure to facilitate the surface mount installation of the device on the PCB board.

[0039] The metal cap 3 is a cylindrical structure formed by stamping Kovar alloy or stainless steel, with one end open and the other closed. An optical window 31 is provided at the center of the closed end. The diameter of the optical window 31 is smaller than the diameter of the cylindrical metal cap 3. It is made of sapphire glass or quartz glass and is sealed and fixed to the closed end of the metal cap 3 by low melting point glass solder. The light-incident surface of the optical window 31 is provided with an anti-reflection film. The wavelength of the anti-reflection film is adapted to the emission wavelength of the laser chip 2 to reduce the reflection loss of the laser at the window. The light emitted by the laser chip 2 can pass through the optical window 31.

[0040] The edge of the opening end of the metal cap 3 has an extension 32 extending radially outward along the main body of the metal cap. The extension 32 abuts against the annular step portion 13 of the support 1 and is bonded and fixed by a modified epoxy adhesive. The modified epoxy adhesive fills the gap between the metal cap 3 and the annular step portion 13 to form a continuous sealing ring, thereby sealing the core components such as the laser chip 2 in the cavity formed by the metal cap 3 and the support 1, providing good protection.

[0041] The laser device in this embodiment, through its reasonable structural design, not only ensures the performance stability and reliability of the laser device, but also facilitates installation using surface mount packaging technology through the bending structure of its external pins, thereby improving production efficiency and assembly accuracy. It is suitable for various laser application scenarios that require surface mount installation.

[0042] Example 2

[0043] This embodiment provides a manufacturing process for laser devices that are easy to surface mount and package, as follows:

[0044] S1 bracket prefabrication: The bracket is injection molded using PPA material to form a basic structure including a recess, annular step and external pins. The external pins are prefabricated into a 90° bent shape. At the same time, a metal heat sink is embedded in the recess and injection molded into the bracket. The side wall of the recess is mirror-finished to form a reflective slope.

[0045] S2 metallization: A copper-nickel-gold three-layer metallized pad is formed at a preset position on the bracket through an electroplating process, and the metallized pad is connected to the external pins through internal circuit wiring.

[0046] S3 laser chip fixing: The laser chip is soldered to the surface of the metal heat sink using eutectic solder to ensure a tight bond between the chip and the heat sink for efficient heat dissipation.

[0047] S4 bonding connection: Using gold or copper wires with a diameter of 20-50μm, the N and P electrodes of the laser chip are connected to the corresponding metallized pads through ultrasonic bonding process to form an electrical signal transmission path.

[0048] S5 metal cap prefabrication: Kovar alloy or stainless steel material is stamped into a cylindrical metal cap that is open at one end and closed at the other. An installation hole is opened in the center of the closed end. The optical window (with a pre-set anti-reflective film on the light-receiving surface) made of sapphire glass or quartz glass is sealed and fixed at the installation hole using low melting point glass solder.

[0049] S6 cap and bracket assembly: Apply modified epoxy adhesive to the annular step of the bracket, precisely align the extension of the metal cap opening with the annular step and apply pressure to fill the gap with adhesive to form a continuous sealing ring. After curing, the two are sealed and fixed, sealing the laser chip and other core components in the cavity.

[0050] S7 Finished Product Inspection: The electrical performance, optical performance and sealing performance of the device are tested. Once qualified, it is a finished laser device that is easy to be surface mount packaged.

[0051] The above examples are merely specific embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments, and many similar modifications are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this utility model should be considered within the scope of protection of this utility model.

Claims

1. A laser device that is easy to surface mount and package, characterized in that, The device includes a support (1), a laser chip (2), and a metal cap (3). The support (1) includes a recess (11), a metallized pad (12), and an annular step (13). A metal heat sink is fixedly embedded in the recess (11). The laser chip (2) is fixed to the upper surface of the metal heat sink by eutectic solder. The metal cap (3) is a cylindrical structure with one end open and the other end closed. The edge of the open end of the metal cap (3) is sealed and fixed to the annular step (13).

2. The laser device facilitating surface mount packaging according to claim 1, characterized in that, An optical window (31) is provided at the sealed end of the metal cap (3), through which the light emitted by the laser chip (2) passes.

3. The laser device facilitating surface mount packaging according to claim 1, characterized in that, The N-electrode and P-electrode of the laser chip (2) are electrically connected to the two metallized pads (12) one-to-one via bonding wires.

4. The laser device facilitating surface mount packaging according to claim 1, characterized in that, The metallized pad (12) has a copper-nickel-gold three-layer plating structure, and the metallized pad (12) is connected to the external pins through the circuit wiring inside the bracket (1).

5. The laser device facilitating surface mount packaging according to claim 2, characterized in that, The optical window (31) is located at the center of the sealed end of the metal cap (3), and the diameter of the optical window (31) is smaller than the diameter of the cylindrical shape of the metal cap (3).

6. The laser device facilitating surface mount packaging according to claim 5, characterized in that, The optical window (31) is made of sapphire glass or quartz glass, and the optical window (31) is sealed and fixed to the sealed end of the metal cap (3) by low melting point glass solder.

7. The laser device facilitating surface mount packaging according to claim 1, characterized in that, The metal cap (3) is a Kovar alloy or stainless steel stamped structure.

8. The laser device facilitating surface mount packaging according to claim 1, characterized in that, The edge of the opening end of the metal cap (3) has an extension (32) that extends radially outward along the main body of the metal cap, and the extension (32) abuts against and is fixed to the annular step portion (13).

9. The laser device facilitating surface mount packaging according to claim 8, characterized in that, The extension (32) and the annular step portion (13) are bonded and fixed by a modified epoxy adhesive, which fills the gap between the metal cap (3) and the annular step portion (13) to form a continuous sealing ring.

10. The laser device facilitating surface mount packaging according to claim 1, characterized in that, The sidewall of the recessed platform (11) is set as an annular inclined surface with a certain tilt angle, which has a reflective function.

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