Copper jumper pin-free packaging structure with side tin climbing function

Abstract

The utility model discloses a copper jumper pin-free packaging structure with a side tin climbing function, which comprises a metal frame, a plurality of chip packaging units arranged in a matrix mode are arranged on the metal frame, and two Y-direction long connecting ribs and two X-direction long connecting ribs are arranged on the peripheral side of each chip packaging unit. The Y-direction long connecting rib is communicated with the two X-direction long connecting ribs; each chip packaging unit comprises a chip welding area arranged in the middle, a left metal contact point and a right metal contact point, the left metal contact point and the right metal contact point are arranged on the left side and the right side of the chip welding area, the right metal contact point is connected with the chip welding area, and the left metal contact point is connected with the adjacent Y-direction long connecting rib and the X-direction long connecting rib. And the semiconductor chip is connected with the left side metal contact point through a copper jumper wire. According to the utility model, the copper jumper wire is adopted for welding, the welding reliability is improved, the external metal contact point realizes a complete tin climbing function, and the welding firmness of a product is improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, and more specifically to a copper jumper leadless packaging structure with side soldering function. Background Technology

[0002] Existing DFN products, after chip soldering, are encapsulated with epoxy resin, then cut into individual materials, exposing the bare copper contact points on the sides. An electroplating process is then used to cover the bare copper bottom with solderable material. To achieve side solder creep functionality at all contact points, existing leadframe structures add two short connecting ribs to one side of the metal contact point, connecting all contact points in series. For example, Chinese patent CN221885104U discloses a leadless semiconductor leadframe. However, this short connecting rib design is a bent structure, making it prone to deformation and short circuits during manufacturing.

[0003] Furthermore, traditional MOSFET packaging typically uses gold, silver alloy, copper, palladium-copper, or aluminum wires as leads to solder the source of the semiconductor chip to metal contacts, thus achieving electrical connection. For example, Chinese patent CN221812090U discloses a leadless semiconductor copper jumper package structure. The front of the chip is connected to the left-side metal solder joint via a connecting metal sheet and metal bonding wires. While this product can achieve leadless side soldering, connecting the chip gate and metal contacts via metal bonding wires requires additional wire bonding equipment. Moreover, using metal bonding wires for electrical connection carries the risk of wire deformation and unstable arc height. Additionally, the metal bonding wires are easily contaminated by flux during soldering, leading to problems such as non-sticking and cold solder joints, affecting package yield. Furthermore, the parasitic resistance and thermal resistance of the wire structure package are relatively high, affecting the electrical characteristics and thermal performance of the packaged device, and resulting in lower reliability.

[0004] For example, Chinese patent CN106298722B discloses a packaging structure and manufacturing method for a high-current power semiconductor device, which uses conductive metal sheets as pins to be directly soldered to the electrodes of the semiconductor chip to increase the device's overcurrent capability. However, this structure does not have the side soldering function of pinless products.

[0005] Therefore, there is an urgent need for a structure that can maximize the wetting area of ​​the bare copper contact points on the side, and has a simpler electrical connection, as well as a stable technology and structure to ensure the reliability of product welding. Summary of the Invention

[0006] The technical problem to be solved by this utility model is to provide a leadless package structure for copper jumpers with side soldering function, so that the external metal contact points can achieve full soldering function, ensuring the stability of the soldering process and soldering effect when the product is soldered to the PCB, and improving the soldering firmness of the product.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0008] A leadless copper jumper package structure with side soldering capability includes a metal frame. The metal frame has several chip packaging units arranged in a matrix for soldering semiconductor chips. Each chip packaging unit has two Y-direction long connecting ribs and two X-direction long connecting ribs on its periphery, and the Y-direction long connecting ribs and the two X-direction long connecting ribs are interconnected. Each chip packaging unit includes a chip soldering area in the middle region for positioning the semiconductor chip, and left and right metal contact points on the left and right sides of the chip soldering area for connecting external circuits, respectively. The right metal contact point is connected to the chip soldering area, while the left metal contact point is away from the chip soldering area and connected to the adjacent Y-direction and X-direction long connecting ribs. The semiconductor chip is connected to the left metal contact point via a copper jumper.

[0009] To further optimize the technical solution, the left-side metal contact point includes one independent left-side metal contact point and three interconnected left-side connected metal contact points. The independent left-side metal contact point is connected to the corresponding side's X-direction long connecting rib via a connecting piece, and the left-side connected metal contact point is connected to the corresponding side's X-direction long connecting rib via a semi-etched connecting piece.

[0010] To further optimize the technical solution, the left-side connected metal contact point is connected to the source of the semiconductor chip via a first copper jumper, and the left-side independent metal contact point is connected to the gate of the semiconductor chip via a second copper jumper.

[0011] To further optimize the technical solution, several positioning holes for positioning the metal frame are provided on both the upper and lower edges.

[0012] To further optimize the technical solution, the back of the metal frame is covered with a high-temperature film to prevent adhesive overflow.

[0013] To further optimize the technical solution, the semiconductor chip, copper jumper, and metal frame are covered with a plastic encapsulation material.

[0014] The technological advancements achieved by this utility model are as follows, due to the adoption of the above technical solutions.

[0015] This utility model provides a copper jumper leadless package structure with side soldering function. The source and gate of the chip are connected to the metal frame through a first copper jumper and a second copper jumper. Copper jumper soldering is used to improve soldering reliability, reduce resistance, and improve heat dissipation. The external metal contact points realize full soldering function, ensuring the stability of the soldering process and soldering effect when the product is soldered to the PCB, and improving the strength of the product soldering. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the metal frame structure of this utility model;

[0017] Figure 2 This is a partially enlarged structural diagram of the back of the metal frame of this utility model;

[0018] Figure 3 This is a partially enlarged structural diagram of the chip-attached surface of the metal frame of this utility model;

[0019] Figure 4 This is a partial schematic diagram of the internal welding structure of the chip packaging unit of this utility model;

[0020] Figure 5 This is a longitudinal cross-sectional view of the chip packaging unit of this utility model after it has been cut into a single chip;

[0021] Figure 6 This is a side view of the chip packaging unit of this utility model.

[0022] Among them: 1. Metal frame, 101. Semiconductor chip, 102. Gate, 103. First copper jumper, 104. Second copper jumper, 105. Molding material, 107. Welding material, 108. Through hole;

[0023] 2. Chip packaging unit, 201. Y-direction long connecting rib, 202a. Connecting piece, 202b. Semi-etched connecting piece, 203. Right side metal contact point, 205a. Left side independent metal contact point, 205b. Left side connected metal contact point, 206. Chip soldering area, 207. X-direction long connecting rib;

[0024] 3. Positioning holes. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] A leadless copper jumper package structure with side soldering capability, combined with Figures 1 to 6 As shown, the device includes a metal frame 1, on which several chip packaging units 2 are arranged in a matrix for welding semiconductor chips 101. Several positioning holes 3 are provided on the upper and lower edges of the metal frame 1 for positioning the metal frame. When welding chips and encapsulating epoxy resin, positioning is achieved through the positioning holes 3 to prevent the metal frame from moving, thus ensuring the reliability and stability of the product.

[0027] The chip packaging unit 2 is provided with two Y-direction long connecting ribs 201 and two X-direction long connecting ribs 207 on its periphery. The Y-direction long connecting ribs 201 and the two X-direction long connecting ribs 207 are interconnected and connected to the metal frame 1 to ensure the connection between each chip packaging unit and the connection between the chip packaging unit and the metal frame.

[0028] The chip packaging unit 2 includes a chip bonding area 206 located in the middle region. The chip bonding area is used to position the semiconductor chip 101. A left metal contact point and a right metal contact point 203 are respectively provided on the left and right sides of the chip bonding area 206. The right metal contact point 203 is connected to the chip bonding area 206, and the left metal contact point is away from the chip bonding area 206 and is connected to the adjacent Y-direction long connecting rib 201 and two X-direction long connecting ribs 207. The semiconductor chip 101 is connected to the left metal contact point through a copper jumper.

[0029] On the back of the metal frame, the left side metal contact points include one independent left side metal contact point 205a and three interconnected left side connected metal contact points 205b. The independent left side metal contact point 205a is connected to the corresponding side X-direction long connecting rib 207 through a connecting piece 202a. The left side connected metal contact points 205b are connected to the corresponding side X-direction long connecting rib 207 through a semi-etched connecting piece 202b. Due to the use of a semi-etching method, the three metal contact points protrude from the semi-etched connecting piece.

[0030] On the die-attached surface, the left-side connecting metal contact 205b is connected to the source of the semiconductor chip 101 via a first copper jumper 103, and the left-side independent metal contact 205a is connected to the gate 102 of the semiconductor chip 101 via a second copper jumper 104, thus achieving electrical conduction between the semiconductor chip 101 and the lower metal frame 1. Due to the use of copper jumpers, the current that can pass through is increased compared to metal bonding wires, while the impedance is reduced. During production, the first and second copper jumpers can be simultaneously bonded to the chip using a single bonding machine, saving one bonding machine compared to traditional wire bonding and improving bonding production efficiency.

[0031] The first copper jumper 103 has three through holes 108 for locking the molding compound, which makes the copper jumper and the molding compound bond more firmly after the molding compound is poured.

[0032] The back side of the semiconductor chip 101 is the drain electrode, which is connected to the chip soldering area 206 by soldering material 107. In this way, the front and back sides of the chip are short-circuited through the metal frame. Due to the principle of equipotential, the chip achieves ESD protection function during the electroplating process.

[0033] The semiconductor chip 101, copper jumper and metal frame 1 are covered with molding compound 105. The back of the metal frame 1 is covered with a high temperature film. During the molding process, the molding compound 105 is flush with the bottom of the packaging unit due to the restriction of the high temperature film, and no glue overflow will occur. At the same time, the molding compound covers the half-etched connection part of the metal contact point, exposing the back metal contact point. After the molding process is completed, the high temperature film is removed.

[0034] In this invention, after the metal frame is molded, the long connecting ribs in the Y direction are cut off, exposing the metal contact points on the sides, followed by electroplating. The connecting tabs ensure that the independent metal contact points on the left and the connected metal contact points on the left are in the conductive circuit of the electroplating process via the long connecting ribs in the X direction. This ensures that all bare copper portions in the electroplating circuit receive a solderable plating layer. After the electroplating process, each chip packaging unit is cut from the entire metal frame, becoming a single material. Because the side metal contacts are covered with solderable material, maximum solderable area can be achieved when the product is subsequently soldered onto the PCB.

Claims

1. A leadless package structure for a copper jumper with side soldering capability, characterized in that: The device includes a metal frame (1), on which a plurality of chip packaging units (2) are arranged in a matrix for welding semiconductor chips (101). Two Y-direction long connecting ribs (201) and two X-direction long connecting ribs (207) are arranged on the periphery of the chip packaging unit (2). The Y-direction long connecting ribs (201) and the two X-direction long connecting ribs (207) are interconnected. The chip packaging unit (2) includes a chip welding area (206) in the middle area for positioning semiconductor chips (101) and a left metal contact point and a right metal contact point (203) on the left and right sides of the chip welding area (206) for connecting external circuits, respectively. The right metal contact point (203) is connected to the chip welding area (206), and the left metal contact point is away from the chip welding area (206) and connected to the adjacent Y-direction long connecting ribs (201) and X-direction long connecting ribs (207). The semiconductor chip (101) is connected to the left metal contact point through a copper jumper.

2. The copper jumper leadless package structure with side solder creep function according to claim 1, characterized in that: The left-side metal contact point includes one independent left-side metal contact point (205a) and three interconnected left-side connected metal contact points (205b). The independent left-side metal contact point (205a) is connected to the corresponding side's X-direction long connecting rib (207) through a connecting piece (202a), and the left-side connected metal contact point (205b) is connected to the corresponding side's X-direction long connecting rib (207) through a semi-etched connecting piece (202b).

3. The copper jumper leadless package structure with side soldering function according to claim 2, characterized in that: The left-side connected metal contact point (205b) is connected to the source of the semiconductor chip (101) via a first copper jumper (103), and the left-side independent metal contact point (205a) is connected to the gate (102) of the semiconductor chip (101) via a second copper jumper (104).

4. The copper jumper leadless package structure with side solder creep function according to claim 1, characterized in that: The upper and lower edges of the metal frame (1) are provided with a number of positioning holes (3) for positioning the metal frame.

5. The leadless package structure of a copper jumper with side soldering function according to claim 1, characterized in that: The back of the metal frame (1) is covered with a high-temperature film to prevent adhesive overflow.

6. The leadless package structure of a copper jumper with side soldering function according to claim 1, characterized in that: The semiconductor chip (101), copper jumper and metal frame (1) are covered with a molding compound (105).

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