Substrate structure of eMMC

Abstract

The utility model discloses a substrate structure of an eMMC, comprising a substrate, a chip and a lead, the chip is arranged on the substrate, the substrate is provided with a plurality of bonding pad pins, the bonding pad pins are arranged at two sides of the chip at intervals, the bonding pad pins and the chip are connected through the lead, and the bonding pad pins are connected with the chip through the lead. A bonding pad assembly is arranged at the lower end of the substrate, and the chip and the bonding pad assembly are arranged in an up-down overlapping mode. According to the substrate structure, the layout of the bonding pads of the substrate is optimized, the welding range is larger, mutual bonding wire superposition is avoided, the packaging difficulty is reduced, and the heat dissipation performance is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of pads, and particularly relates to a substrate structure of an eMMC. Background Art

[0002] eMMC (Embedded Multi Media Card) is an embedded memory chip that integrates a controller chip and a flash memory chip and provides a standard interface. It is mainly used in mobile phones, tablets, smart TVs, set-top boxes, etc. The new generation of eMMC 5.1 can support the HS400 high-speed mode, and the interface speed is as high as 400MB / s.

[0003] The controller chip of the eMMC has 75-90 pad interfaces. In order to support high-density stacked packaging, all pads are arranged in an L shape. In the traditional packaging pad design, the two outermost WB lines on the horizontal sides are relatively long, with a large gap compared to the shorter WB lines in the middle, which affects the equal length of signal lines. Secondly, the two outermost WB lines on the horizontal sides are extremely long and relatively isolated. The molding and encapsulation will cause certain pressure damage to the extremely long and isolated WB lines, and even cause disconnection and open circuit, greatly increasing the cost and process difficulty.

[0004] Therefore, it is necessary to provide a substrate structure of an eMMC to solve the above problems. Content of the Utility Model

[0005] In order to overcome the deficiencies of the prior art, the utility model provides a substrate structure of an eMMC, which optimizes the layout of the substrate pads, has a larger weldable range, avoids the superposition of bonding wires, reduces the packaging difficulty, and effectively improves the heat dissipation performance.

[0006] The technical solution adopted by the utility model to solve its technical problems is as follows:

[0007] A substrate structure of an eMMC includes a substrate, a chip, and leads. The chip is disposed on the substrate. A plurality of pad pins are disposed on the substrate, and the pad pins are spaced on both sides of the chip. The pad pins are connected to the chip through the leads. A pad assembly is disposed at the lower end of the substrate, and the chip and the pad assembly are arranged in an overlapping manner up and down.

[0008] As a further improvement of the above technical solution, the pad assembly includes a pad and a plurality of solder balls. The pad is connected to the lower end of the substrate, and the plurality of solder balls are disposed at the lower end of the pad.

[0009] As a further improvement of the above technical solution, an OSP film is further disposed between the pad and the substrate.

[0010] As a further improvement of the above technical solution, the chip includes a controller chip and a flash memory chip, and both the controller chip and the flash memory chip are disposed in the middle of the substrate.

[0011] As a further improvement of the above technical solution, the pad pins include a first pin and a second pin. The first pin is disposed on one side of the controller chip, and the second pin is disposed on one side of the flash memory chip.

[0012] As a further improvement of the above technical solution, a plurality of the first pins are arranged in a multi-row fan-shaped distribution, and a plurality of the second pins are arranged in a single-row linear distribution.

[0013] As a further improvement of the above technical solution, the lead includes a bonding wire and a plating lead. The controller chip is connected to the first pin through the bonding wire, and the flash memory chip is connected to the second pin through the plating lead.

[0014] As a further improvement of the above technical solution, the plating lead is disposed at the edge of the substrate.

[0015] The beneficial effects of the present utility model are as follows:

[0016] By improving the four-row pad interface design of the controller chip in the prior art into a fan-shaped radial pad layout, the present utility model enables the bonding wires in different rows to be staggered from each other, resulting in a larger weldable range and avoiding mutual superposition that may affect the molding and encapsulation. At the same time, the storage chip is designed with a single-row pad, and plating leads are pulled at the edge of the substrate, reducing the residual wire tails after etching and solving the problem that the residual wire tails affect the structural function and appearance. In addition, the control chip and the pad solder balls are overlapped up and down, and the bottom pad solder balls are used for heat conduction to improve the heat dissipation performance. Description of the Drawings

[0017] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0018] Figure 1 is a schematic diagram of the encapsulation structure of the substrate structure of the present utility model;

[0019] Figure 2 is a schematic diagram of the encapsulation structure of the controller chip of the present utility model;

[0020] Figure 3 is a schematic diagram of the encapsulation structure of the flash memory chip of the present utility model;

[0021] Figure 4 is a schematic diagram of the side view structure of the substrate structure of the present utility model;

[0022] Figure 5 is a schematic diagram of the structure of the pad assembly of the present utility model.

[0023] Reference numerals: 1, substrate; 11, first pin; 12, second pin; 2, controller chip; 3, flash memory chip; 4, pad; 5, solder ball; 6, OSP film; 7, bonding wire; 8, electroplated lead wire. Detailed implementation mode

[0024] The concept, specific structure and technical effects of the present utility model will be clearly and completely described below in conjunction with the embodiments and the drawings, so as to fully understand the purpose, features and effects of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present utility model. In addition, all connection / connection relationships involved in the patent do not refer to the direct connection of components alone, but refer to the more optimal connection structure that can be formed by adding or reducing connection accessories according to the specific implementation situation. For example, fixed connection / fixed installation can be selected from screw connection, bolt connection, pin connection, key connection, bonding, tenon and mortise connection, welding, riveting and other methods as needed. For example, detachable connection can be selected from screw connection, bolt connection, threaded connection, snap connection, tenon and mortise connection, magic tape connection and other methods as needed. Each technical feature in the creation of the present utility model can be combined interactively without conflicting with each other.

[0025] Refer to Figure 1 , Figure 4 , a substrate structure of an eMMC, comprising a substrate 1, a chip and a lead wire. Among them, the chip includes a controller chip 2 and a flash memory chip 3. The controller chip 2 and the flash memory chip 3 are both fixedly installed in the middle of the substrate 1, and both sides of the chip provide a connection space for the lead wire. At the same time, a plurality of pad pins are arranged on the substrate 1, and the plurality of pad pins are arranged at intervals on both sides of the chip, so that the pad pins are convenient to be connected to the corresponding chip through the lead wire, and at the same time, the length of the lead wire is greatly shortened, which is more convenient for plastic packaging, reduces the difficulty of WB packaging and the difficulty of substrate manufacturing, and ensures that the eMMC can work normally. A pad assembly is also arranged at the lower end of the substrate 1, and the chip and the pad assembly are arranged up and down overlappingly, and the heat can be conducted and released by welding the solder balls of the eMMC pad to the application end, so as to achieve the purpose of heat dissipation and temperature rise control.

[0026] Refer to Figure 4 , Figure 5, in an embodiment of the present utility model, the pad assembly includes a pad 4 and a plurality of solder balls 5. The pad 4 is connected to the lower end of the substrate 1, and the plurality of solder balls 5 are arranged at the lower end of the pad 4. The solder balls 5 are solder balls formed by stencil printing, providing an interface for soldering with the application component to ensure stable data transmission and reliable operation of the device; an OSP film 6 is further arranged between the pad 4 and the substrate 1. The OSP film 6 is an organic protective film or copper protection agent, which can protect the copper surface from oxidation, and at the same time provide good soldering performance, avoiding complex electroplating leads and etching problems; at the same time, the solder balls 5 are overlapped and arranged under the chip, and heat is conducted and released through the soldering of the solder balls to the application end, improving the heat dissipation performance.

[0027] Referring to Figures 1 to 3 , in an embodiment of the present utility model, the pad pins include a first pin 11 and a second pin 12. The leads include a bonding wire 7 and an electroplated lead 8. The first pin 11 is arranged on one side of the controller chip 2. The controller chip 2 is connected to the first pin 11 through the bonding wire 7. In this embodiment, the conventional four-row horizontal layout of the package pads of the controller chip is changed to a three-row fan-shaped distribution. In the fan-shaped layout, it is ensured that the lengths of the multiple bonding wires connecting the first pin 11 and the controller chip 2 are closer to being equal, and the bonding wires in different rows are staggered from each other, so that the solderable range is larger and they are prevented from overlapping with each other. Adopting this layout reduces the risk of the bonding wires being easily damaged by pressure during the molding and encapsulation process, improving the reliability and durability of the product.

[0028] At the same time, the second pin 12 is arranged on one side of the flash memory chip 2. The flash memory chip 3 is connected to the second pin 12 through the electroplated lead 8. The plurality of second pins 12 are arranged in a single-row straight line. The electroplated lead 8 is arranged at the edge of the substrate 1. In this embodiment, a single-row pad layout of the flash memory chip is adopted, and the electroplated lead 8 is pulled at the board edge of the substrate 1 or the process edge of the substrate, ensuring that the residual wire tail is the shortest after the substrate is cut, and the residual wire tail does not affect the function and appearance. At the same time, it can also avoid the phenomenon that the air cavity caused by the electroplated lead etching pit trace in the chip area expands due to heat and causes bubbles or delamination defects.

[0029] The above is a specific description of the preferred embodiment of the present utility model. However, the present utility model is not limited to the above embodiments. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present utility model, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A substrate structure of an eMMC, characterized in that: It includes a substrate, a chip, and leads. The chip is disposed on the substrate. Multiple pad pins are provided on the substrate. The pad pins are spaced apart on both sides of the chip, and the pad pins are connected to the chip through the leads. A pad assembly is provided at the lower end of the substrate, and the chip and the pad assembly are arranged in an overlapping manner up and down. The pad pins include first pins and second pins. Multiple first pins are arranged in a multi-row fan-shaped distribution, and multiple second pins are arranged in a single-row linear distribution.

2. The substrate structure of an eMMC according to claim 1, characterized in that: The pad assembly includes a pad and multiple solder balls. The pad is connected to the lower end of the substrate, and multiple solder balls are provided at the lower end of the pad.

3. The substrate structure of an eMMC according to claim 2, wherein: An OSP film is also provided between the pad and the substrate.

4. The substrate structure of an eMMC according to claim 1, characterized in that: The chip includes a controller chip and a flash memory chip, and both the controller chip and the flash memory chip are disposed in the middle of the substrate.

5. The substrate structure of an eMMC according to claim 4, wherein: The first pins are provided on one side of the controller chip, and the second pins are provided on one side of the flash memory chip.

6. The substrate structure of an eMMC according to claim 5, characterized in that: The leads include bonding wires and electroplated leads. The controller chip is connected to the first pins through the bonding wires, and the flash memory chip is connected to the second pins through the electroplated leads.

7. The substrate structure of an eMMC according to claim 6, wherein: The electroplated leads are provided at the edge of the substrate.

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