阅读说明：本技术 一种实现电磁屏蔽的sip封装方法 (SIP packaging method for realizing electromagnetic shielding ) 是由 姜显扬 陈木市 王德富 徐欣 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种实现电磁屏蔽的SIP封装方法。传统采用表面金属化防辐射干扰,增加了模块连接的尺寸。本发明方法首先对SIP模块中的MCU芯片和Flash存储芯片的上下表面使用吸收材料进行全表面涂抹,形成屏蔽层,采用的吸收材料为石墨烯。采用上下叠层的封装方法,将MCU芯片和Flash存储芯片采用SPI总线连接,进行相互通信。然后通过正向键合方式将MCU芯片与基板连接,通过反向键合方式将Flash存储芯片与基板连接。本发明方法可以有效吸收电磁波,减少渗透到芯片中的电磁场,进而提高信号的传输质量以及减少EMI问题。引线采用反向的方式键合,能够有效减少堆叠封装的高度。(The invention discloses an SIP packaging method for realizing electromagnetic shielding. The traditional adoption surface metallization is protected against radiation and is disturbed, has increased the size that the module is connected. The method comprises the steps of firstly, coating the upper surface and the lower surface of an MCU chip and a Flash memory chip in an SIP module on the whole surface by using an absorbing material to form a shielding layer, wherein the absorbing material is graphene. And an upper and lower laminated packaging method is adopted, and the MCU chip and the Flash memory chip are connected by an SPI bus to carry out mutual communication. And then the MCU chip is connected with the substrate in a forward bonding mode, and the Flash memory chip is connected with the substrate in a reverse bonding mode. The method can effectively absorb electromagnetic waves, reduce the electromagnetic field penetrating into the chip, further improve the transmission quality of signals and reduce the EMI problem. The leads are bonded in a reverse mode, and the height of the stacked package can be effectively reduced.)

1. A SIP packaging method for realizing electromagnetic shielding is characterized in that:

firstly, coating the whole surfaces of an MCU chip and the upper and lower surfaces of a Flash memory chip in an SIP module by using an absorbing material to form a shielding layer, wherein the coating is not carried out on edge pins of the MCU chip and the Flash memory chip; the absorbing material is graphene;

after the coated absorption material is dried, placing the MCU chip below the Flash memory chip, coating a bonding agent between the MCU chip and the Flash memory chip, and then connecting the MCU chip and the Flash memory chip by adopting an SPI bus for mutual communication;

placing the MCU chip and the Flash memory chip which are connected on a substrate; connecting the MCU chip with the substrate in a forward bonding mode, and bonding a lead from the MCU chip to the substrate; the Flash memory chip is connected with the substrate in a reverse bonding mode, and the lead is bonded to the Flash memory chip from the substrate.

2. The SIP packaging method for implementing electromagnetic shielding according to claim 1, wherein: the thickness of the shielding layer is 25-100 mu m.

Technical Field

The invention belongs to the technical field of chips, particularly relates to the technical field of chip packaging, and relates to an SIP packaging method for realizing electromagnetic shielding.

Background

As the integration of two-dimensional integrated circuits is further advanced, the semiconductor industry is approaching the bottleneck of the expansion of transistors, and three-dimensional (3D) integration technology is regarded as a promising solution, which can expand moore's law for the next generation of semiconductor technology. The chip lamination packaging is a three-dimensional encapsulation technology, functional chips such as a processor, a storage chip, an encryption chip and the like can be integrated in one packaging to realize a complete function, so that an integrated circuit is continuously developed towards miniaturization, high performance, high integration and low cost.

However, new applications place new demands on the electrical characteristics, compact structure and system reliability of integrated products. Since the three-dimensional package is made of heterogeneous materials such as semiconductor materials, metal materials, insulating materials, etc., the electromagnetic environment inside the package is rather harsh. In addition, electromagnetic interference (EMI) in the packaged chip will be caused due to the external complex electromagnetic environment. Therefore, how to overcome the internal and external interference of the 3D integrated circuit package becomes one of the major research directions.

The traditional method for solving the external radiation is to metalize the surface of the SIP (System In a Package) module product, and although the scheme slows down the radiation interference of the external electromagnetic environment to the internal chip of the SIP to a certain extent, the size of the connection between the PCB board and the SIP module is increased, which is not favorable for the final miniaturization trend of the product. Therefore, it is extremely important to perform electromagnetic shielding inside the SIP module.

Disclosure of Invention

The invention aims to provide an SIP packaging method for realizing electromagnetic shielding, which can overcome the harm of EMI (electro-magnetic interference) caused by external complex electromagnetic environment to a chip, thereby improving the working efficiency of the chip.

The specific method of the invention is as follows:

firstly, the upper and lower surfaces of the MCU chip and the Flash memory chip in the SIP module are coated on the whole surface by using absorption materials to form a shielding layer, and the edge pins of the MCU chip and the Flash memory chip are not coated. The shielding layer is of a thin coating structure, the thickness of the shielding layer is 25-100 mu m, and the adopted absorbing material is graphene. Graphene is a carbon-based filler, and has the advantages of low density, high strength, high temperature resistance, chemical corrosion resistance, low thermal expansion coefficient and the like. Graphene is an ideal two-dimensional structure and has good electrical conductivity characteristics, and thus has excellent electromagnetic interference shielding properties.

The packaging method adopting the upper and lower lamination comprises the following steps: because the Flash memory chip is smaller than the MCU chip, the Flash memory chip is arranged above the MCU chip, and the MCU chip is arranged below the Flash memory chip, corresponding pins of the MCU chip are interconnected through wire bonding stacking, and the packaging space size is effectively saved. The method comprises the following steps:

and after the coated absorption material is dried, placing the MCU chip below the Flash memory chip, coating a bonding agent between the MCU chip and the Flash memory chip, and connecting the MCU chip and the Flash memory chip by adopting an SPI bus to carry out mutual communication.

Placing the MCU chip and the Flash memory chip which are connected on a substrate; connecting the MCU chip with the substrate in a forward bonding mode, and bonding a lead from the MCU chip to the substrate; the Flash memory chip is connected with the substrate in a reverse bonding mode, and the lead is bonded to the Flash memory chip from the substrate, so that a ring formed on the Flash memory chip is lower, and a ring formed on the substrate is higher. By the lead bonding mode, the height of the stacked package can be effectively reduced.

When external electromagnetic waves are transmitted to the absorption material, the graphene material forming the shielding layer can absorb and reflect the external electromagnetic waves, so that the interference of the electromagnetic waves is weakened. When part of electromagnetic waves pass through the absorption material, the graphene material is attached to the upper surface and the lower surface of the chip to form a shielding body, so that the electromagnetic waves are weakened through multiple reflections inside the shielding body. Finally, the effect of shielding electromagnetic interference is achieved.

The invention forms a high-storage chip system, effectively overcomes the problem that an MCU chip cannot meet the insufficient data storage space, can effectively save the size of a packaging space by stacking chips through wire bonding, adds a layer of adhesive between the chips, is beneficial to improving the flexibility between the chips and improving the impact strength between the chips, has more reliable absorption material than electromagnetic shielding material, has the characteristics of low density and high temperature resistance, can effectively absorb electromagnetic waves, reduces the electromagnetic field penetrating into the chips, further improves the transmission quality of signals and reduces the EMI problem. The leads are bonded in a reverse mode, and the height of the stacked package can be effectively reduced.

Drawings

FIG. 1 is a schematic diagram of an internal package of a chip system according to the present invention.

Detailed Description

In order to better explain the working of the invention, a detailed description of the invention with completeness and clarity is given below with reference to the specific drawing.

An SIP packaging method for realizing electromagnetic shielding specifically comprises the following steps:

as shown in FIG. 1, the hardware of the invention comprises a high-capacity Flash memory chip 1, an MCU chip 2 and a substrate 3, which form a high-memory chip system, and effectively overcomes the problem that the MCU chip cannot meet the shortage of data storage space.

Firstly, the upper and lower surfaces of the Flash memory chip 1 and the MCU chip 2 are coated with the whole surface by using an absorbing material to form a shielding layer 4. The edge pin 1-1 of the Flash memory chip 1 and the edge pin 2-1 of the MCU chip 2 are not coated. The thickness of the shielding layer 4 is 25-100 μm (50 μm is adopted in the embodiment), the adopted absorbing material is graphene which is an ideal two-dimensional structure and has good electrical conductivity, so that the shielding layer has excellent electromagnetic interference shielding performance, can effectively absorb and reflect electromagnetic waves, reduces EMI (electro-magnetic interference), and is more reliable than an electromagnetic shielding material, and the absorbing material has the advantages of low density, high strength, high temperature resistance, chemical corrosion resistance, low thermal expansion coefficient and the like.

The structure of the shielding layer 4 is selected as the shielding according to various structures of the absorbing material, and unnecessary occupied space can be greatly reduced. The plane of the absorbing material can effectively absorb electromagnetic waves as a shielding layer, and reduces the electromagnetic field penetrating into the chip, thereby improving the transmission quality of signals and reducing the EMI problem. The size and coverage of the absorbent material coating can be freely defined.

The MCU chip 2 is arranged below the Flash memory chip 1, and the MCU chip and the Flash memory chip are bonded through the bonding layer 5, so that the flexibility between the chips is improved, and the impact strength between the chips is improved. The MCU chip and the Flash memory chip are connected by an SPI bus (not shown in the figure).

Placing the MCU chip and the Flash memory chip which are connected on a substrate 3; connecting the MCU chip 2 with the substrate 3 in a forward bonding mode, and bonding a lead from a pin 2-1 at the edge of the MCU chip to a pin 3-1 of the substrate; the Flash memory chip 1 and the substrate 3 are connected in a reverse bonding mode, and the lead is bonded to the edge pin 1-1 of the Flash memory chip from the pin 3-1 of the substrate, so that a ring formed on the Flash memory chip is lower, and a ring formed on the substrate is higher. By the lead bonding mode, the height of the stacked package can be effectively reduced.