Research on the packaging technology of the hottes

Research on epoxy plastic packaging technology IV

4.2 EMC application

● packaging of discrete devices, Different packaging forms put forward different requirements for the properties of epoxy molding compounds (Table 4)

● integrated circuit packaging

at present, integrated circuits are developing towards high integration, fine wiring, large-scale chip and surface mounting technology. The corresponding research and development of epoxy molding materials is to make the materials have the performance characteristics of high purity, low stress, low expansion and high heat resistance. See Table 5 (taking Huawei products as an example)

5 development trend

emc, as the main support of IC packaging industry, immediately shut down and check the transmission system materials. Its development is closely following the development of the whole machine and packaging technology

development trend of the whole machine: light and small (portability); High speed; Add functions; Improve reliability; Cost reduction; Less environmental pollution

development trend of packaging technology: small, thin, light and high-density package outline; From single chip to multi chip in scale; The structure develops from two-dimensional to three-dimensional assembly; The development of packaging materials from ceramic to plastic; In terms of price, the cost shows a downward trend

with the rapid development of high and new technology, the semiconductor application technology is continuously promoted, so more stringent requirements are put forward for its epoxy packaging materials. In the future, epoxy molding compounds will mainly develop in the following five aspects:

(1) to the direction of high performance and low price suitable for surface packaging. In order to meet the high performance and low price of molding materials, new epoxy resins suitable for this requirement are emerging. Crystalline resins have excellent operability due to their low molecular weight, low melting viscosity and high melting point. They are suitable for high flow packaging materials. In order to obtain the melting point range suitable for packaging materials, most of the existing crystalline epoxy resins are grafted with soft molecular segments, but the formability and heat resistance are difficult to meet the requirements of packaging materials, so it is necessary to develop new crystalline epoxy resins

(2) develop towards packaging materials suitable for flip chip [2]. Recently, with the development of electronic industry, as a method to improve high-density installation, the so-called bare die installation has attracted great attention. In the flip chip installation, liquid packaging materials are used to protect the chip from the pollution of the external environment. In liquid packaging materials, it is required to infiltrate and fill the gap between the chip and the substrate. Because this infiltration and filling is ultimately carried out through the capillary principle, it is required that the resin has very high fluidity and the inorganic filling rate should be reduced. However, the stress between the liquid packaging material and the chip will increase, so it is required that the plastic packaging material must have a low coefficient of linear expansion. Now foreign countries use a new type of epoxy resin with naphthalene ring structure to prepare the plastic packaging material

(3) new packaging methods such as BGA and CSP require the development of new materials [3]. Although the bare die installation method is an ideal method to realize high-density packaging, there are still some problems, such as installation device and chip quality assurance. A new packaging method, BGA or CSP, has emerged, which is a lattice joint packaging method. It can not only realize miniaturization, lightweight, but also achieve high-speed transmission. At present, this packaging form is in a rapid growth period. However, warpage occurs in the cooling process after this process, which is caused by the different shrinkage between the substrate and the packaging material. The solution is to make the linear expansion coefficient of the packaging material close to that of the substrate as much as possible. From both the packaging material and the substrate adhesive, it is necessary to develop new EMC and improve the adhesion between the protective film and the material

(4) EMC with high heat dissipation. With the development of electronic instruments, the issue of heat dissipation of packaging materials has been raised. Because the EMC matrix material - epoxy resin is an organic polymer material, the improvement of thermal conductivity is limited based on different molecular structures. Therefore, starting from the metal material of the lead frame, 42, Therefore, EMC is required to have good adhesion with it. Some foreign manufacturers are researching and developing to improve the attraction of vanderwa bpi751 L/L by introducing chain segments, so as to improve the attraction between EMC and copper frame

(5) green environmental protection EMCT: with the increasing voice of global environmental protection, green environmental protection packaging is the requirement of market development. At present, Huawei electronics adopts the epoxy resin system without flame retardant or the green environmental protection EMC with higher filling volume without flame retardant is being commercialized. Some foreign companies are also experimenting with phosphorus containing compounds, including red phosphorus and phosphorus

in a word, with the rapid development of integrated circuits towards super large scale, ultra-high speed, high density, high power, high precision and multi-function, and the development of electronic packaging technology from through-hole insertion (PHT) to surface mount technology, the packaging form has developed from dual in-line (DIP) to (thin) Quad lead flat packaging (tqfp/qfp), ball grid array plastic packaging (PBGA) and chip size packaging (CSP), The development direction of epoxy molding compound/emc is towards high purity, high reliability, high heat conduction, high welding resistance, high moisture resistance, high bonding strength, low stress, low expansion, low viscosity, easy processing, low environmental pollution, etc. (by chengxingming)