Capacitor or inductor packaging structure and packaging method thereof

Abstract

The invention provides a capacitor or inductor packaging structure and a packaging method thereof, and belongs to the technical field of electronic component packaging. The structure is a finished product which is provided with two independent conductive terminals after being packaged into a plastic package body, and has the function of a capacitor or an inductor. Electrodes at two ends of the capacitor or the inductor are welded with the corresponding conductive terminals; and an area, which is welded with the electrode of the capacitor or the inductor and is provided with a silver coating, on each conductive terminal is exposed out of the plastic package body. The method comprises the steps of silver coating preparation, welding, plastic packaging and the like. Through the design of the independent terminal, the silver-plated welding area and the overall plastic package insulation, the problems that in the traditional technology, welding spots are directly welded on tin layers at the two ends of a capacitor or an inductor, the welding spots are subjected to insufficient welding and are prone to falling off, and the reliability is low are solved, and the insulativity and the welding reliability of the capacitor and the packaging frame base island in the packaging module are achieved. Therefore, the stability of long-term use can be achieved.

Description

Technical Field

[0001] This invention relates to the field of electronic component manufacturing technology, specifically to a high-reliability capacitor or inductor packaging structure and its packaging method. Background Technology

[0002] In existing passive device packaging processes, tin-plated capacitors or inductors are often placed directly inside the package module. This process has two major drawbacks: First, the capacitor electrodes are connected to the internal wiring using wire bonding, which makes it difficult to form a strong eutectic bond, resulting in a "false solder joint." During the subsequent high-temperature molding process, the solder joints are prone to detaching due to thermal stress, leading to device failure. Second, the bottom of the capacitor is in direct contact with the underlying metal frame (such as copper). To achieve insulation between the electrodes, additional insulating adhesive is required for bonding and isolation. However, "tin spikes" that may form on the tin layers at both ends of the capacitor can easily pierce the insulating adhesive, causing a short circuit between the electrodes, severely affecting the reliability and lifespan of the module. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art and provide a capacitor or inductor packaging structure and packaging method that is firmly welded, reliably insulated, and structurally stable.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: On one hand, a capacitor or inductor packaging structure is provided, comprising a capacitor or inductor, two independent conductive terminals, and a molding compound. Electrodes are respectively disposed at both ends of the capacitor or inductor, and the electrodes are soldered to the corresponding conductive terminals. The molding compound covers the capacitor or inductor and a portion of the conductive terminals. Specifically, a region on each conductive terminal that is soldered to the capacitor or inductor electrode and has a silver plating layer is exposed outside the molding compound.

[0005] Preferably, the electrodes at both ends of the capacitor or inductor are tin-plated electrodes. This design facilitates the formation of reliable solder joints with the silver-plated conductive terminals.

[0006] Preferably, the encapsulation is made of a high-voltage resistant insulating material to provide excellent electrical isolation performance.

[0007] Preferably, the bottom of the capacitor or inductor is insulated from the supporting structure (such as a lead frame or substrate) to which the conductive terminal is connected by the encapsulation, thereby fundamentally avoiding the risk of short circuit between the bottom of the capacitor or inductor and the supporting conductor.

[0008] On the other hand, a capacitor packaging method is provided, which includes the following steps: S1. Provide a capacitor or inductor, and form electrodes at both ends of the capacitor or inductor; S2. Provide two independent conductive terminals, and prepare a silver plating layer on each of the conductive terminals; S3. Weld the electrodes at both ends of the capacitor or inductor to the silver plating layer on the corresponding conductive terminal, respectively; S4. The welded capacitor or inductor and some conductive terminals are encapsulated with molding compound to form a molding compound, and the silver plating area on each of the conductive terminals is exposed.

[0009] Preferably, the electrodes at both ends of the capacitor or inductor are formed by a tin plating process.

[0010] Preferably, the welding process is reflow soldering or wave soldering.

[0011] Preferably, the molding compound is epoxy molding compound (EMC).

[0012] Preferably, the method further includes a high-temperature baking process after molding to eliminate internal stress and further improve reliability.

[0013] Preferably, the conductive terminal is formed by cutting and separating a metal frame, and the silver plating layer preparation and welding steps are completed before cutting, which facilitates mass production. Beneficial effects

[0014] Compared with the prior art, the present invention has the following significant advantages: 1. High welding reliability: Utilizing independent conductive terminals, the capacitor or inductor electrodes are directly connected to the silver plating layer on the conductive terminals via welding, forming a strong metallurgical bond and completely avoiding the problem of "false welding." The solder joints remain stable and do not detach during high-temperature baking and aging after encapsulation.

[0015] 2. Excellent insulation performance and strong short-circuit protection: Through a one-time molding process using a single encapsulation material, the encapsulated body itself possesses excellent high-voltage resistance and insulation, completely isolating the capacitor and its connection points from the external environment (including the underlying support structure). No additional insulating adhesive is required, and the risk of short-circuit failure due to solder spikes piercing the insulation material is completely eliminated.

[0016] 3. Good process compatibility, suitable for wire bonding: The exposed conductive terminal area has a silver plating layer, which provides an excellent and easy-to-solder metal base layer for subsequent wire bonding processes, ensuring the convenience and reliability of module connection with external circuits. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a cross-sectional schematic diagram of a capacitor or inductor packaging structure according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, 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.

[0019] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] See Figure 1 As shown, this embodiment provides a capacitor or inductor packaging structure. The structure includes a chip capacitor or inductor 10, a first conductive terminal 21 and a second conductive terminal 22 (which are independent of each other), and a plastic encapsulation 30.

[0021] The capacitor or inductor 10 is a passive surface-mount component, with electrodes 11 and 12 respectively disposed at its first and second ends. In this embodiment, the electrodes 11 and 12 are preferably tin-plated electrodes formed by electroplating or deposition processes. This tin plating layer facilitates subsequent soldering processes.

[0022] The first conductive terminal 21 and the second conductive terminal 22 are made of a metal material with good conductivity (such as a copper alloy) and are set independently. A silver plating layer 23 is pre-prepared on each conductive terminal 21, 22. The silver plating layer 23 can be prepared using conventional processes such as electroplating or chemical plating.

[0023] The tin-plated electrodes 11 and 12 at both ends of the capacitor or inductor 10 are soldered to the silver-plated layer 23 on the corresponding conductive terminals 21 and 22 using a reflow soldering process. This soldering method can form a stable alloy solder joint, achieving a firm electrical and mechanical connection between the capacitor or inductor electrodes and the external terminals. It fundamentally solves the problem of solder joint detachment caused by "false soldering" in the prior art, and remains stable even during subsequent high-temperature processes.

[0024] Epoxy molding compound (EMC) is used as the molding compound. Through a transfer molding process, the soldered capacitor or inductor 10 and a portion of the conductive terminals 21 and 22 are encapsulated to form a monolithic molded body 30. The molded body 30 is made of high-voltage resistant insulating material, providing excellent electrical and mechanical insulation protection for the entire packaging structure and enhancing the environmental tolerance of the device.

[0025] Crucially, during molding, the area with the silver plating layer 23 on each conductive terminal 21, 22 (i.e., the soldering connection area) is exposed outside the molding compound 30. The exposed silver plating surface provides an ideal interface for subsequent soldering of this package structure to a PCB or wire bonding with other components, resulting in good soldering performance and high reliability.

[0026] Simultaneously, during the molding process, the molding compound fully fills all the space between the bottom of the capacitor or inductor 10 and the underlying support structure (not shown in the figure, such as the rest of the lead frame or circuit board). This ensures complete insulation between the bottom of the capacitor or inductor 10 and the support structure through the molding compound 30. Thus, the use of insulating adhesive is eliminated, and the possibility of short circuits between the bottom conductor of the capacitor and the underlying metal components due to contact or "solder spikes" is completely eliminated, greatly improving the long-term reliability of the product.

[0027] The capacitor or inductor packaging method of the present invention, based on the above structure, mainly includes the following steps: First, a capacitor or inductor 10 is provided, with tin-plated electrodes 11 and 12 formed at its two ends.

[0028] Secondly, two independent conductive terminals 21 and 22 are provided, and a silver plating layer 23 is formed in their predetermined connection areas by electroplating.

[0029] Next, the tin-plated electrodes 11 and 12 at both ends of the capacitor or inductor 10 are soldered together with the silver-plated layer 23 on the corresponding conductive terminals by reflow soldering or wave soldering.

[0030] Then, the welded semi-finished product is placed in the mold, epoxy molding compound is injected, and compression molding is performed to form an encapsulating body 30, ensuring that the silver plating layer 23 area on the conductive terminal is exposed.

[0031] Afterwards, the sealed product can be baked at high temperature to solidify the molding compound and release internal stress, further improving reliability.

[0032] In a preferred embodiment for mass production, the conductive terminals 21 and 22 are initially part of a continuous metal frame. Steps such as the preparation of the silver plating layer 23 and the soldering of the capacitors or inductors 10 are all performed on the frame. After all steps are completed, the individual package structures are separated from the frame (i.e., a specific form of the aforementioned carrier structure) using a cutting process. This improves production efficiency, ensures good consistency, and is suitable for mass production.

[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A capacitor or inductor packaging structure, characterized in that, include: Capacitor or inductor; Two independent conductive terminals; The capacitor or inductor has electrodes at both ends, and the electrodes are welded to the corresponding conductive terminals. A plastic encapsulation that covers the capacitor or inductor and part of the conductive terminals; In this embodiment, the area on each of the conductive terminals that is welded to the electrodes of the capacitor or inductor and has a silver plating layer is exposed outside the encapsulation.

2. The capacitor or inductor packaging structure according to claim 1, characterized in that, The electrodes at both ends of the capacitor or inductor are tin-plated electrodes.

3. The capacitor or inductor packaging structure according to claim 1, characterized in that, The encapsulation body is made of high-voltage resistant insulating material.

4. The capacitor or inductor packaging structure according to claim 1, characterized in that, The bottom of the capacitor or inductor is insulated from the carrier structure to which the conductive terminal is connected by the encapsulation.

5. A method for packaging a capacitor or inductor, characterized in that, Includes the following steps: Provide a capacitor or inductor, and form electrodes at both ends of the capacitor or inductor; Two independent conductive terminals are provided, and a silver plating layer is prepared on each of the conductive terminals; The electrodes at both ends of the capacitor or inductor are respectively welded to the silver plating layer on the corresponding conductive terminal; The welded capacitor or inductor and some conductive terminals are encapsulated with molding compound to form a molding compound, and the silver plating area on each of the conductive terminals is exposed.

6. The capacitor or inductor packaging method according to claim 5, characterized in that, The electrodes at both ends of the capacitor or inductor are formed by a tin plating process.

7. The capacitor or inductor packaging method according to claim 5, characterized in that, The welding process employs either reflow soldering or wave soldering.

8. The capacitor or inductor packaging method according to claim 5, characterized in that, The molding compound is an epoxy molding compound.

9. The capacitor or inductor packaging method according to claim 5, characterized in that, The method also includes a step of high-temperature baking after molding.

10. The capacitor or inductor packaging method according to claim 5, characterized in that, The conductive terminal is formed by cutting and separating a metal frame, and the silver plating layer preparation and welding steps are completed before cutting.

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