An optical relay structure adopting a clip packaging structure and a double-wire bonding process

Abstract

The utility model relates to photoelectric device technical field especially relates to a kind of light relay structure using Clip packaging structure and double soldering line technology, including output lead frame and input lead frame, output end uses Clip structure to replace traditional soldering line, its high conductivity, high heat conduction metal material and greater cross-sectional area, can greatly reduce on-resistance and parasitic inductance, significantly improve product current-carrying capacity, switching speed and anti-electromagnetic interference ability, simultaneously build additional efficient heat dissipation path for PT chip, effectively reduce chip working junction temperature, guarantee reliability and long-term life under large current working condition, and input end and PVG end retain mature and low-cost soldering line technology, only key output large current path uses Clip structure, both improve efficiency and control cost, avoid full flip chip high investment, and the mechanical strength and connection reliability of Clip structure are superior to multiple parallel soldering lines, can reduce the failure risk caused by vibration or thermal fatigue, further improve product stability.

Description

Technical Field

[0001] This utility model relates to the field of optoelectronic device technology, and in particular to an optical relay structure using a Clip packaging structure and a double wire bonding process. Background Technology

[0002] An opto-relay is a semiconductor device that uses light signals to control the on / off state of a circuit. It typically consists of an input-side light-emitting element (such as an infrared LED, or an IR opto-relay structure LED using a Clip package and double-wire bonding process) and an output-side photosensitive element (such as a photothyristor, phototransistor, or PT chip). The two are coupled through an optical channel, achieving electrical isolation between the input and output.

[0003] For products requiring current carrying capacity greater than 1A, traditional fine gold or silver wire bonding methods suffer from high parasitic inductance, high resistance, and poor heat dissipation. This limits current carrying capacity and switching speed, and also causes the junction temperature of the PT chip to rise when conducting high current, shortening the product's lifespan. While flip-chip technology can improve performance, it requires additional chip bump fabrication and high mounting precision, significantly increasing manufacturing costs and making it unsuitable for cost-sensitive applications. Furthermore, the mechanical strength of traditional multi-parallel bonding wires is relatively weak, making them prone to connection failure under vibration or thermal fatigue conditions, severely impacting the long-term operational stability of the product. Therefore, we provide a photorelay structure employing a Clip package structure and dual-wire bonding technology. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a photoelectric relay structure using a Clip packaging structure and dual wire bonding process. This solves the problems of high parasitic inductance, high resistance, and poor heat dissipation associated with traditional high-current photoelectric relays using fine gold / silver wire bonding, as well as the high cost of flip-chip technology and the weak mechanical strength and susceptibility to failure of multiple parallel wire bonding lines. This achieves the following: improved current carrying capacity, switching speed, and electromagnetic interference resistance of the photoelectric relay; reduced chip junction temperature; controlled manufacturing costs; reduced failure risk; and improved product reliability and long-term stability.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: an optical relay structure using a Clip packaging structure and a double wire bonding process, including an output lead frame and an input lead frame.

[0006] An IR chip is mounted on the input lead frame, and a PT chip is fixed to the output lead frame with conductive adhesive. The top electrode of the PT chip is connected to the non-chip bonding pad of the output lead frame via a Clip structure. A PVG chip and a light-emitting diode chip are mounted on the output lead frame, and multiple sets of connecting wires are connected to the output lead frame.

[0007] Preferably, the PVG chip is bonded to the output lead frame or the trigger motor of the PT chip via a set of connecting wires.

[0008] Preferably, the IR chip, PT chip and PVG chip form a vertical optical path through a transparent colloid inside the package, and the package is made of white opaque material to block external light interference.

[0009] Preferably, the output lead frame and the input lead frame are isolated from each other and partially embedded in the package.

[0010] Preferably, the Clip structure is a stamped bracket made of copper or a highly conductive and thermally conductive metal, with a cross-sectional area larger than that of a traditional bonding wire.

[0011] Preferably, the conductive adhesive is silver paste or sintered silver, and the connecting wire is gold wire or silver wire.

[0012] By employing the above technical solution, this utility model provides an optical relay structure using a Clip packaging structure and a dual wire bonding process, which has at least the following beneficial effects: 1. The output terminal of this utility model adopts a Clip structure to replace the traditional bonding wire. Its highly conductive and thermally conductive metal material and larger cross-sectional area significantly reduce the on-resistance and parasitic inductance, and significantly improve the product's current carrying capacity, switching speed and anti-electromagnetic interference capability. At the same time, the Clip structure provides an additional efficient heat dissipation path for the PT chip, which can effectively reduce the chip's operating junction temperature and ensure the product's reliability and long service life under high current conditions.

[0013] 2. This utility model retains mature and low-cost wire bonding technology at the input and PVG ends, and only uses the Clip structure in the critical high-current output path. While significantly improving performance, it effectively controls the overall manufacturing cost and avoids the high investment of expensive solutions such as full flip-chip. In addition, the mechanical strength and connection reliability of the Clip structure are better than multiple parallel wire bonding, which can reduce the risk of failure caused by vibration or thermal fatigue and further improve product stability. Attached Figure Description

[0014] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0015] In the attached diagram: Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a side view of the structure of this utility model; Figure 3 This is a schematic diagram of the output lead frame structure of this utility model; Figure 4 This is a schematic diagram of the input lead frame structure of this utility model.

[0016] In the diagram: 1. Output lead frame; 2. Input lead frame; 3. IR chip; 4. PT chip; 5. Clip structure; 6. PVG chip; 7. Light-emitting diode chip; 8. Connecting wire. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] To address the issues of high parasitic inductance, high resistance, and poor heat dissipation associated with traditional high-current optocouplers using fine gold / silver wire bonding, as well as the high cost of flip-chip technology and the weak mechanical strength and susceptibility to failure of multiple parallel bonding wires, this embodiment provides an optocoupler structure employing a Clip packaging structure and dual-wire bonding technology. This structure improves the optocoupler's current carrying capacity, switching speed, and electromagnetic interference immunity, reduces chip junction temperature, controls manufacturing costs, reduces failure risk, and enhances product reliability and long-term stability. Please refer to... Figure 1 - Figure 4 The opto-relay structure, which adopts a Clip packaging structure and dual wire bonding process, includes an output lead frame 1 and an input lead frame 2. The output lead frame 1 and the input lead frame 2 are isolated from each other and partially embedded in the package, ensuring the realization of the core functions and reliable operation of the opto-relay. The isolation between them can accurately meet the core requirement of electrical isolation between the input and output of the opto-relay.

[0019] For opto-relay products that need to carry current greater than 1A, traditional fine gold or silver wire bonding has obvious shortcomings: large parasitic inductance, high resistance and poor heat dissipation, which not only limits the current carrying capacity and switching speed, but also causes the junction temperature of the PT chip 4 to rise when conducting large current, shortening its service life. In order to solve the above problems...

[0020] An IR chip 3 is mounted on the input lead frame 2, and a PT chip 4 is fixed to the output lead frame 1 using conductive adhesive, which is either silver paste or sintered silver. This adhesive provides a triple function of "fixation + conductivity + thermal conductivity" for the output lead frame 1 and the PT chip 4. Physical bonding stably fixes the PT chip 4 to the output lead frame 1, ensuring the structural reliability of the connection under high current conditions. Simultaneously, the excellent conductivity of silver creates a current path between the PT chip 4 and the output lead frame 1, ensuring efficient high-current transmission. Furthermore, the high thermal conductivity of silver aids in heat dissipation for the PT chip 4, forming a dual heat dissipation path with the output clip structure 5: "bottom (adhesive) + top (Clip structure 5)," further reducing the operating junction temperature of the PT chip 4. To improve product lifespan, the top electrode of the PT chip 4 is connected to the non-chip bonding pad of the output lead frame 1 through the Clip structure 5. The Clip structure 5 is a stamped bracket made of copper or a highly conductive and thermally conductive metal, with a cross-sectional area larger than that of traditional bonding wires. On the one hand, relying on the highly conductive material and the larger cross-sectional area, the on-resistance and parasitic inductance of the high-current output path can be significantly reduced, effectively overcoming the limitations of traditional fine gold / silver wire bonding on current carrying capacity (adapting to current requirements greater than 1A), switching speed and electromagnetic interference resistance. On the other hand, the highly thermally conductive material can build an additional efficient heat dissipation path for the PT chip 4. Combined with the large cross-sectional area to enhance heat conduction, it significantly reduces the operating junction temperature of the PT chip 4 when conducting at high current, ensuring product reliability and long lifespan.Meanwhile, the stamped bracket's structure gives it mechanical strength far exceeding that of traditional multi-parallel bonding wires, reducing the risk of connection failure due to vibration or thermal fatigue. This structure is used only for the critical high-current output path, complementing the low-cost bonding wire technology retained at the input and PVG ends. This improves performance while avoiding the high investment required for flip-chip designs, achieving the design goal of "high performance + low cost." A PVG chip 6 and a light-emitting diode chip 7 are mounted on the output lead frame 1. The PVG chip 6 is bonded to the trigger electrode of the output lead frame 1 or the PT chip 4 via a set of connecting wires 8. The IR chip 3, PT chip 4, and PVG chip 6 form a vertical optical path through a transparent gel within the package. This vertical optical path constructed with gelatin is for light signal transmission. The key carrier enables the efficient and directional transmission of the optical signal emitted by the IR chip 3 (the control signal on the input side of the photorelay) to the PT chip 4 and PVG chip 6, ensuring the optical coupling efficiency among the three. The package is made of white, opaque material to block external light interference, preventing stray light from interfering with the accurate recognition of the IR chip 3's optical signal by the PT chip 4 and PVG chip 6. If external light intrudes, it may cause the PT chip 4 to mis-trigger (conducting when there is no internal optical signal) or decrease its trigger sensitivity (interference with the internal optical signal), ultimately affecting the accuracy and stability of the photorelay's operation. Multiple sets of connecting wires 8 are connected to the output lead frame 1. These connecting wires 8 are gold or silver wires, adapted to "low-cost wire bonding technology," and enable the transfer of key signals / energy.

[0021] When this opto-relay structure is working, the IR chip 3 on the input lead frame 2 emits a light signal. The IR chip 3, PT chip 4, and PVG chip 6 form a vertical optical path through a transparent colloid within the package. The package is made of a white, opaque material to block external light interference. The output lead frame 1 is fixed to the PT chip 4 with conductive adhesives such as silver paste or sintered silver. The PVG chip 6 is bonded to the trigger electrode of the output lead frame 1 or the PT chip 4 through connecting wires 8 such as gold or silver wires. When the light signal from the IR chip 3 is transmitted to the PT chip 4 and PVG chip 6 through the optical path, the PVG chip 6 triggers the PT chip 4 to conduct, and current flows into the output lead frame 1. The Clip structure 5 (copper or high-conductivity, high-thermal-conductivity metal stamped bracket) transmits the signal to the PT chip 4 and then back to the output lead frame 1 to form a conductive path. Because the cross-sectional area of ​​the Clip structure 5 is larger than that of traditional bonding wires, it can significantly reduce the on-resistance and parasitic inductance. At the same time, it provides an additional heat dissipation path for the PT chip 4 to reduce its operating junction temperature. The output lead frame 1 and the input lead frame 2 are isolated from each other and partially embedded in the package, ensuring electrical isolation between the input and output and overall structural stability. Ultimately, it realizes the switching on and off of the light control circuit. The cost is controlled by the bonding process of the connecting line 8 between the input end and the PVG end. The Clip structure 5 at the output end improves mechanical strength and reduces the risk of failure caused by vibration or thermal fatigue.

[0022] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0023] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A photoelectric relay structure employing a Clip packaging structure and dual wire bonding process, comprising an output lead frame (1) and an input lead frame (2), characterized in that: An IR chip (3) is attached to the input lead frame (2). A PT chip (4) is fixed to the output lead frame (1) by a conductive adhesive. The top electrode of the PT chip (4) is connected to the non-chip bonding pad of the output lead frame (1) by a Clip structure (5). A PVG chip (6) and a light-emitting diode chip (7) are mounted on the output lead frame (1). Multiple sets of connecting wires (8) are connected to the output lead frame (1).

2. The opto-relay structure using a Clip package structure and dual wire bonding process according to claim 1, characterized in that: The PVG chip (6) is bonded to the output lead frame (1) or the trigger motor of the PT chip (4) via a set of connecting lines (8).

3. The opto-relay structure using a Clip package structure and dual wire bonding process according to claim 1, characterized in that: The IR chip (3), PT chip (4) and PVG chip (6) form a vertical optical path through a transparent colloid inside the package, and the package is made of white opaque material to block external light interference.

4. The opto-relay structure using a Clip package structure and dual wire bonding process according to claim 1, characterized in that: The output lead frame (1) and the input lead frame (2) are isolated from each other and partially embedded in the package.

5. The opto-relay structure using a Clip package structure and dual wire bonding process according to claim 1, characterized in that: The conductive adhesive is silver paste or sintered silver, and the connecting wire (8) is gold wire or silver wire.

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