3G has improved the communication speed, 4G has changed our lives, and the 5G era has had a profound impact on the whole social and commercial forms because of the revolutionary technology. It has also brought a lot of new technological innovations in the field of chip packaging and testing.
In early November, at the 5G Communication Chip topic Forum of the 2018 China Integrated Circuit Industry Promotion Conference, Zhou Yin, customer quality Engineering Director of Qorvo Asia Pacific, used examples to introduce in detail the traditional chip packaging and testing process and the evolution of 5G chip packaging technology.
Qorvo is one of the few companies in the world that can integrate all RF solutions, and its main business areas include mobile terminals, base station chips, aerospace and so on. If you want to do a good job, you must first sharpen its tools. Two years ago, the new Texas plant, which was put into operation, is the largest assembly, packaging and testing operation center in the world of Qorvo, which complements Qorvo's existing manufacturing operations in Beijing and forms a Qorvo China manufacturing center with Qorvo Beijing factory to support global production and operations. The article is extracted from the author of "5G Technology Analysis",Dr.Mao Lifei of Topscom, published on China electronics Network in 2020. Topscom provide pcb boards design and layout,pcb assembly box build, turnkey full systems integration electronic contract manufacturing service.
This is a typical laminated packaging structure model (Laminate Module Package), based on substrate (Substrate) more than ten years ago, which can be roughly divided into several steps: first, the passive components of pcb smt assembly are mounted on the surface of the substrate, that is, capacitors and inductors that we usually use. The second step is to stick the active element, that is, the wafer in the middle, which realizes most of the circuit functions of the chip. After these two steps are done, it is necessary to connect the circuit, which used to be connected with gold wire, copper wire and aluminum wire to realize the circuit function of the chip. After these three steps, the function of the chip is basically realized, and then some materials, such as ceramics or polyester, are used to plastic the chip to ensure reliability. This is the most basic and simple process of encapsulation.
1 wafer grinding and cutting process.
2 flip chip placement process.
Pasting a passive component in a chip is similar to attaching a component to a pcb board. Brush it with solder paste and weld the passive component to the substrate to achieve its connection function. The only difference is that it uses smaller SMD components. The trend in the future is that more discrete components will be integrated into the chip, and there will not be too many components on the periphery.
As power amplification devices, we need high-power, high-bandwidth materials, such as gallium arsenide and gallium nitride, as well as some low-frequency power devices to be made on the wafer. Each wafer may contain many small wafers about 0.1mm to 0.5mm in diameter, which we call die. The special machine for the wafer will use epoxy resin to glue the wafer to the target surface, so that the target and the wafer are connected with electrical conductivity and heat conduction. Epoxy resin materials have certain restrictions on the distance between die and die. As the wafers become smaller and smaller, some other new materials, such as conductive films, may be used to improve the integration of the chip.
3 wire bonding process.
The solder wire (Wire Bond) connects the circuits on the chip. Now a mil (1/1000 inch, about 0.0254mm) gold wire is used for wire soldering, as well as alloy, aluminum wire or other welding wire materials, along with cost control and other production considerations. Different die use this kind of wire to connect to each other.
Although the chip with soldering wire has high flexibility in substrate design, the soldering wire restricts the size of the package. As the frequency band becomes wider and wider and the spectrum becomes more and more complex, soldering wire technology is no longer suitable for consumer electronics, especially wearable devices. Now it is commonly used to realize the connection in the chip by inverting the bump of the copper column.
4 plastic packaging molding technology.
Before plastic sealing.
After plastic sealing.
Finally, we use epoxy resin, silicon dioxide or other materials to plastic the chip to achieve the reliability of the product, such as moisture-proof, shock-proof and so on. After the plastic packaging is completed, it will be laser coded on the chip, leaving some basic information, through which the production record of the chip can be traced back. After coding, the whole chip will be cut into a single chip package.
5 cutting process.
6 test.
Including magnetoresistive testing, whole board testing, dry baking testing, wafer detection and so on.
/ / the continuous evolution of RF chip packaging mode / /.
Throughout the evolution of the chip packaging mode, 5murl 10 years ago, most of the devices were packaged in Wire Bond spaced mode, through the wafer affixed to the substrate similar to the traditional PCB, to achieve thinner and higher density. Or the mixed mode of multiple wafers and surface mount components separated by Wire Bond can package some other functions of wafer, such as control module, power management module, filter, including switch.
The packaging mode of five years ago is now still in use in many mainstream mobile phones and base station products, more often in the way of upside-down stickers. The next package will be more and more integrated. System-level package (System In a Package) can integrate a variety of functional chips, including processors, memory and other functional chips into one package, so as to achieve a basic and complete function. The article is extracted from the author of "5G Technology Analysis",Dr.Mao Lifei of Topscom, published on China electronics Network in 2020. Topscom provide pcb board design and layout,pcb assembly box build, turnkey full systems integration contract electronic manufacturing service.
In addition, 5G promotes the development of chips to higher integration, smaller size and higher performance, and the new packaging technology requires the continuous improvement of design and manufacturing capabilities. Finally, Zhou Yin pointed out that the, Qorvo RF Fusion RF front-end module has achieved a breakthrough in functional integration, and the if / HF modules can be integrated together. By using Qorvo's unique core function combination, it can improve performance, reduce power consumption and the overall size of the solution, while providing higher carrier aggregation capacity to meet the growing global coverage needs of smartphone manufacturers in the 5G era.
