An automatic silicon controlled rectifier chip packaging structure and process thereof

Abstract

The application discloses an automatic silicon controlled chip packaging structure and a process thereof, and relates to the technical field of silicon controlled chip packaging. The automatic silicon controlled chip packaging structure and the process thereof comprise a base, a silicon controlled chip and a top box. The silicon controlled chip comprises an anode terminal, a cathode terminal and a gate terminal. A back-shaped groove is formed in the bottom end of the base, and a metal block is fixed in the back-shaped groove. A bottom cavity is formed in the bottom of the base, and a side rectangular groove which is in communication with the bottom cavity is formed around the base. The application is provided with external pins, solder pins, hollow blocks, elastic plates and polar leads. Tin particles are put into the hollow blocks through solder interfaces, and then are put into a heating furnace after being compacted by vibration, so that the tin particles are melted, and the electrical conduction between the external pins and the polar leads is further realized. The implementation of the scheme can prevent the external pins and the polar leads from being separated or cracked, and the gas bubbles in the tin can be discharged by the vacuum degree of the heating furnace.

Description

Technical Field

[0001] This invention relates to the field of thyristor chip packaging technology, specifically to an automated thyristor chip packaging structure and its process. Background Technology

[0002] A thyristor, short for silicon controlled rectifier, is a high-power semiconductor device with a four-layer structure containing three PN junctions. It typically consists of two thyristors connected in reverse. Its function extends beyond rectification; it can also be used as a contactless switch to quickly connect or disconnect circuits, converting direct current (DC) to alternating current (AC), or changing AC frequency from one to another. Like other semiconductor devices, thyristors offer advantages such as small size, high efficiency, good stability, and reliable operation. They are widely used in AC contactless switches, household appliance control circuits, and industrial control systems.

[0003] Currently, in the packaging of thyristors, due to the relatively small size of the thyristor modules, the soldering of the wires between the various components can easily result in a high void ratio and low solder joint strength, which can easily lead to cracking or solder joint detachment, resulting in poor packaging quality. This has varying degrees of impact on the heat dissipation and conductivity of the components during use. To address these issues, an automated thyristor chip packaging structure and its process are proposed. Summary of the Invention

[0004] The purpose of this invention is to provide an automated silicon controlled rectifier chip packaging structure and process to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automated silicon controlled rectifier (SCR) chip packaging structure and its process, comprising a base, a SCR chip, and a top box. The SCR chip includes an anode terminal, a cathode terminal, and a gate terminal. The base has a U-shaped groove at its bottom end, in which a metal block is fixed. A bottom cavity is formed at the bottom of the base. Rectangular side grooves communicating with the bottom cavity are formed around the base, connecting the bottom cavity to the metal block. Multiple first circular through holes communicating with the bottom cavity are formed at the top of the base. A packaging box is fixed at the top of the base. Three rectangular through grooves are formed on one side of the packaging box. A hollow block is fixed outside the rectangular through grooves. An external lead is fixed on one side of the hollow block. A lead wire is fixed at one end of the anode terminal, cathode terminal, and gate terminal. One side of the lead wire is inserted into the hollow block. A solder inlet is formed at the top of the hollow block.

[0006] Furthermore, the base has a second circular through hole on both sides of the top end that communicates with the bottom cavity. The top of the circular through hole is provided with an inlet pipe and a riser pipe that are fixed to the base. Thermally conductive adhesive is injected into the bottom cavity.

[0007] Furthermore, the base has a placement groove at its top, which is connected to the first circular through hole. A ceramic copper-clad plate is fixed at the top of the placement groove, and the ceramic copper-clad plate is located at the bottom of the thyristor chip.

[0008] Furthermore, the upper and lower inner walls of the rectangular through groove are both fixed with elastic plates. The elastic plates are V-shaped and made of copper. Both elastic plates are pressed against the electrode leads.

[0009] Furthermore, the external pins include solder pads located inside the hollow block.

[0010] The automated silicon controlled rectifier (SCR) chip packaging process includes the following steps:

[0011] S1. Place the ceramic copper-clad laminate into the placement slot;

[0012] S2. Place the thyristor chip on top of the base and push the thyristor chip so that the electrode leads connecting the anode terminal, cathode terminal and gate terminal are inserted into the hollow block;

[0013] S3. Add solder particles into the hollow block through the solder inlet;

[0014] S4. Place the semi-finished product obtained through step S3 into a vibratory machine for vibration, then take it out and add tin particles again;

[0015] S5. Place the semi-finished product obtained in step S4 into a heating furnace and heat it for a period of time. Then take out the semi-finished product and let it cool to room temperature.

[0016] S6. Take out the semi-finished product after cooling in step S5, inject molten thermally conductive adhesive into the bottom cavity through the glue inlet tube, and then put it into the heat preservation box for cooling.

[0017] S7. The semi-finished product obtained in step S6 and the top box are sealed with encapsulating adhesive.

[0018] Furthermore, in step S5, the vacuum degree of the heating furnace is 0.8MPa-1MPa, the heating temperature of the heating furnace is 300-400℃, and the heating time is 40-50min.

[0019] Furthermore, in step S6, the temperature of the insulation box is 30-40℃, and the insulation time is 30-40 minutes.

[0020] Furthermore, in step S7, the encapsulating adhesive is made by mixing epoxy resin and alumina thermally conductive powder.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This automated silicon controlled rectifier (SCR) chip packaging structure and process includes external leads, solder pads, a hollow block, a flexible plate, and electrode leads. Solder particles are placed into the hollow block through a solder interface, vibrated and compacted, and then placed in a heating furnace for heating. This melts the solder particles, thereby achieving electrical conductivity between the external leads and electrode leads. This solution prevents the connection between the external leads and electrode leads from detaching or cracking. The vacuum of the heating furnace allows air bubbles in the liquefied solder to be expelled, further improving the physical strength of the connection.

[0023] In addition, a ceramic copper-clad plate, a metal block, a bottom cavity, and a side rectangular groove are provided. Thermally conductive adhesive is injected into the bottom cavity. The thermally conductive adhesive can conduct the heat emitted by the thyristor chip to the metal block, and then dissipate heat through the metal block. The implementation of this solution improves the heat dissipation effect and enhances the performance of the thyristor chip. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a top view of the present invention after the set-top box has been removed;

[0026] Figure 3 This is an axial view of the present invention after the top box has been removed;

[0027] Figure 4 This is a half-section view of the right front side after removing the set-top box;

[0028] Figure 5 This is a half-section view of the right rear side after removing the set-top box.

[0029] In the diagram: 1. Base; 101. Bottom cavity; 102. Side rectangular groove; 2. Metal block; 3. Packaging box; 4. Top box; 501. Hollow block; 502. Solder inlet; 503. Elastic plate; 601. External lead; 602. Soldering foot; 7. Electrode lead; 801. Adhesive inlet tube; 802. Riser tube; 9. Silicon control chip; 10. Ceramic copper clad laminate. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0031] It should be noted that in the description of this invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0034] like Figures 1-5 As shown, the present invention provides a technical solution: an automated silicon controlled rectifier (SCR) chip packaging structure and its process, including a base 1, a SCR chip 9, and a top box 4. Both the base 1 and the top box 4 are made of insulating and high-temperature resistant PVC material. It is known that the SCR chip 9 includes an anode terminal, a cathode terminal, and a gate terminal. In order to enable the SCR chip 9 to dissipate heat quickly, a U-shaped groove is provided at the bottom of the base 1 in this solution, and a metal block 2 is fixed in the U-shaped groove. The U-shaped groove and the metal block 2 can be fixed by adhesive bonding or laser connection. Laser connection is a mature existing technology and will not be described in detail in this embodiment. Since copper has good corrosion resistance, and copper also has excellent thermal conductivity and ductility, in this embodiment, the metal block 2 is made of copper material.

[0035] The base 1 has a bottom cavity 101 at its bottom, and rectangular side grooves 102 connected to the bottom cavity 101 are also formed around the base 1. It is known that the rectangular side grooves 102 connect the bottom cavity 101 to the metal block 2. For example, when a high temperature is generated in the bottom cavity 101, the temperature comes into contact with the surface of the metal block 2 through the rectangular side grooves 102. Through the principle of heat conduction, the metal block 2 dissipates the temperature in the bottom cavity 101 to the outside. Multiple first circular through holes connected to the bottom cavity 101 are formed at the top of the base 1. A packaging box 3 is fixed at the top of the base 1. To improve the practicality of this solution, the packaging box 3 and the base 1 can be integrally formed by injection molding. Three rectangular through grooves are formed on one side of the packaging box 3, and a hollow block 501 is fixed on the outside of the rectangular through grooves.

[0036] Similarly, to facilitate the production of this device, the encapsulation box 3 and the hollow block 501 can be integrally molded using injection molding. An external pin 601 is fixed to one side of the hollow block 501. A lead wire 7 is fixed to one end of each of the anode terminal, cathode terminal, and gate terminal. The lead wire 7 can be integrally molded with the anode terminal, cathode terminal, and gate terminal, or it can be soldered to the anode terminal, cathode terminal, and gate terminal using a conductive metal with a higher melting point than tin. One side of the lead wire 7 is inserted into the other side of the hollow block 501. It should be noted that a solder inlet 502 is provided at the top of the hollow block 501. Elastic plates 503 are fixed on the upper and lower inner walls of the rectangular through slot. The elastic plates 503 are V-shaped with rounded chamfers at the ends. The elastic plates 503 are preferably made of copper plates with good elasticity and conductivity. It is known that both elastic plates 503 are pressed against the electrode lead 7 to fix the electrode lead 7. In addition, the outer pin 601 includes a soldering foot 602. The soldering foot 602 is integrally formed with the outer pin 601. The height of the soldering foot 602 is less than the height of the outer pin 601. The soldering foot 602 is located in the middle of the end of the outer pin 601 and is located inside the hollow block 501.

[0037] To further enhance heat dissipation of the silicon controlled rectifier chip 9, such as... Figure 3 and Figure 4 As shown, the base 1 has a second circular through hole on both sides of the top end that communicates with the bottom cavity 101. A glue inlet pipe 801 and a riser pipe 802 fixed to the base 1 are provided at the top of the second circular through hole. Thermally conductive glue is injected into the bottom cavity 101 through the glue inlet pipe 801. It can be seen that the riser pipe 802 is provided firstly to allow the air in the bottom cavity 101 to be discharged during the injection of thermally conductive glue, and secondly to allow the glue in the bottom cavity 101 to be filled more fully.

[0038] To facilitate the installation of the silicon controlled rectifier (SCR) chip 9, a placement groove is provided at the top of the base 1, and the placement groove is adapted to the bottom of the SCR chip 9. It is understood that the placement groove is connected to the first circular through hole. Preferably, thermally conductive adhesive can also be applied to the bottom of the SCR chip 9 to improve the connection stability of the SCR chip 9. Preferably, a ceramic copper-clad plate 10 is fixed at the top of the placement groove, and the ceramic copper-clad plate 10 is fixed to the bottom of the SCR chip 9.

[0039] The thyristor chip packaging process includes the following steps:

[0040] S1. Place the ceramic copper-clad laminate 10 into the placement groove. Specifically, thermally conductive adhesive is applied to the bottom of the ceramic copper-clad laminate 10 to achieve initial fixation of the ceramic copper-clad laminate 10.

[0041] S2. Place the thyristor chip 9 on top of the base 1 and push the thyristor chip 9 so that the electrode lead 7 connecting the anode terminal, cathode terminal and gate terminal is inserted into the hollow block 501. Thermally conductive adhesive is also coated on the bottom of the thyristor chip 9 to achieve initial fixation of the thyristor chip 9, which facilitates subsequent reprocessing. During the insertion of the electrode lead 7 into the hollow block 501, the electrode lead 7 compresses the two elastic plates 503. Under the reaction force of the elastic plates 503, the electrode lead 7 can be fixed. In addition, the compression of the elastic plates 503 by the elastic plates 503 can block the side cavity of the hollow block 501.

[0042] S3. Tin particles are added into the hollow block 501 through the solder inlet 502. The tin particles are molten tin that is blown into shape by a tin blowing machine.

[0043] S4. Place the semi-finished product obtained through step S3 into a vibratory machine for vibration, then take it out and add tin particles again. It can be seen that after the initial vibration, the tin particles in the hollow block 501 are compacted, and some cavities appear in the cavity of the hollow block 501. The cavity of the hollow block 501 is filled by adding tin particles again.

[0044] S5. The semi-finished product obtained in step S4 is placed in a heating furnace for heating. After heating for a period of time, the semi-finished product is taken out and cooled to room temperature. The vacuum degree of the heating furnace is 0.8MPa-1MPa, the heating temperature of the heating furnace is 300-400℃, and the heating time is 40-50min. Preferably, in this embodiment, the vacuum degree of the heating furnace is maintained at 0.9MPa, the heating temperature is 380℃, and the heating time is 40min. This step can melt the tin particles.

[0045] S6. Take out the semi-finished product after cooling in step S5, and inject molten thermal conductive adhesive into the bottom cavity 101 through the glue inlet tube 801. It is known that the amount of molten thermal conductive adhesive injected is calculated in advance and can be injected directly through the injection machine. Then, put the semi-finished product into the heat preservation box for cooling. The temperature of the heat preservation box is 30-40℃ and the heat preservation time is 30-40min. In this embodiment, the temperature of the heat preservation box is set to 30℃ and the heat preservation time is set to 40min.

[0046] S7. The semi-finished product obtained in step S6 is encapsulated with top box 4 using encapsulating adhesive. The encapsulating adhesive is made by mixing epoxy resin and alumina thermal conductive powder. Since alumina thermal conductive powder has a certain thermal conductivity, the epoxy resin and alumina thermal conductive powder mixture has good thermal conductivity after curing, thereby further increasing the thermal conductivity of the encapsulation structure.

[0047] Although embodiments of the 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 invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automated silicon controlled rectifier (SCR) chip packaging process, characterized in that: Includes the following steps: S1. Place the ceramic copper-clad laminate (10) into the placement slot; S2. A package box (3) is fixed at the top of the base (1). Three rectangular through slots are opened on one side of the package box (3). A hollow block (501) is fixed on the outside of the rectangular through slots. The thyristor chip (9) is placed on the top of the base (1). The thyristor chip (9) is pushed so that the electrode lead (7) connecting the anode terminal, cathode terminal and gate terminal is inserted into the hollow block (501). S3. Add tin particles into the hollow block (501) through the solder inlet (502); S4. Place the semi-finished product obtained through step S3 into a vibratory machine for vibration, then take it out and add tin particles again; S5. Place the semi-finished product obtained in step S4 into a heating furnace and heat it for 40-50 minutes. Then take out the semi-finished product and let it cool to room temperature. S6. The base (1) has a bottom cavity (101). Take out the semi-finished product after cooling in step S5, inject molten thermally conductive adhesive into the bottom cavity (101) through the glue inlet pipe (801), and then put it into the heat preservation box for cooling. S7. The semi-finished product obtained in step S6 and the top box (4) are sealed with encapsulating glue.

2. The automated silicon controlled rectifier (SCR) chip packaging process according to claim 1, characterized in that: In step S5, the vacuum degree of the heating furnace is 0.8MPa-1MPa, and the heating temperature of the heating furnace is 300-400℃.

3. The automated silicon controlled rectifier (SCR) chip packaging process according to claim 1, characterized in that: In step S6, the temperature of the insulation box is 30-40℃, and the insulation time is 30-40 minutes.

4. The automated silicon controlled rectifier (SCR) chip packaging process according to claim 1, characterized in that: In step S7, the encapsulating adhesive is made by mixing epoxy resin and alumina thermally conductive powder.

5. An automated thyristor chip packaging structure, manufactured by the thyristor chip packaging process according to any one of claims 1-4, comprising a base (1), a thyristor chip (9), and a top box (4), wherein the thyristor chip (9) comprises an anode terminal, a cathode terminal, and a gate terminal, characterized in that: The base (1) has a U-shaped groove at the bottom, and a metal block (2) is fixed in the U-shaped groove. The base (1) has side rectangular grooves (102) that are connected to the bottom cavity (101) around its perimeter. The side rectangular grooves (102) connect the bottom cavity (101) and the metal block (2). The base (1) has multiple first circular through holes that are connected to the bottom cavity (101) at the top. An external pin (601) is fixed on one side of the hollow block (501). A pole lead (7) is fixed on one end of the anode terminal, cathode terminal and gate terminal. One side of the pole lead (7) is inserted into the other side of the hollow block (501). A solder inlet (502) is opened at the top of the hollow block (501).

6. The automated silicon controlled rectifier chip packaging structure according to claim 5, characterized in that: The base (1) has a second circular through hole on both sides of the top end that is connected to the bottom cavity (101). The top of the second circular through hole is provided with an adhesive inlet pipe (801) and a riser pipe (802) that are fixed to the base (1). Thermally conductive adhesive is injected into the bottom cavity (101).

7. The automated silicon controlled rectifier chip packaging structure according to claim 5, characterized in that: The base (1) has a placement groove at the top, which is connected to the first circular through hole. A ceramic copper-clad plate (10) is fixed at the top of the placement groove, and the ceramic copper-clad plate (10) is located at the bottom of the thyristor chip (9).

8. The automated silicon controlled rectifier chip packaging structure according to claim 5, characterized in that: The upper and lower inner walls of the rectangular through groove are fixed with elastic plates (503). The elastic plates (503) are V-shaped and made of copper. Both elastic plates (503) are pressed against the electrode lead (7).

9. The automated silicon controlled rectifier (SCR) chip packaging structure according to claim 5, characterized in that: The external pin (601) includes a solder pad (602) located inside the hollow block (501).

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