Chip packaging is a process that a chip must go through. You can understand it as a shell for integrated circuits. It plays a role in placing, fixing, sealing and protecting the chip, and enhancing the electrothermal performance. It is a signal bridge between the internal world of the chip and external circuits. The quality of packaging plays a key role in the stability and reliability of signals and the life of the chip. In this issue, Heketai will explain two popular chip packaging forms, which are used in many electronic products.

As an advanced chip packaging form, DFN packaging and QFN packaging have something in common, that is, they are both lead-free surface mount packaging structures, they both have the characteristics of modern bottom-discharge and top-embedded packaging, they all have the advantages of small size, easy integration, good consistency, miniaturization, light weight and thinness, and their bottoms usually have good thermal conductivity, which can effectively dissipate heat and improve the reliability and stability of chips. Both of them have good electrical properties and uniformity.



In addition, they can realize large-scale automatic production through SMT equipment, and their packaging has high flexibility and strong applicability, and the application scenarios are diverse. DFN packaging and QFN packaging can be widely used in Internet of Things, computers, communications, automotive electronics, smart home appliances, security, wearable, medical equipment, industrial control equipment, instruments and meters, and consumer electronic products. However, there are many differences between the two packages.

What are the main differences between DFN package and QFN package?

1. The distribution positions of package pads are different.

The pads of DFN package are distributed around the chip, while those of QFN package are concentrated at the bottom of the chip.

Second, the difference between welding structure and bottom material

QFN package is usually lead-free welded structure, and the product has the characteristics of lower inductance and capacitance reactance. The bottom of QFN package is generally made of copper, which has better thermal conductivity and electrical properties and can effectively dissipate heat.

Third, the side length range of the package is different.

The shape of DFN package is slimmer, and the commonly used width is usually less than 1mm, while the side length of QFN package is generally between 2-7 mm.

Fourth, some application scenarios are different.

For example, DFN packaging has been widely used in demand markets such as high frequency, high speed and high precision. In 5G communication, the antenna body is usually packaged by DFN, and many sensors, lighting driver chips, printer sensors and so on used in medical, industrial and automobile applications are packaged by DFN.

QFN package is more suitable for power amplifiers, battery charging management chips, automatic control equipment chips and entertainment electronic products, and its compact size and high integration are very practical.

In addition, the shapes of DFN package and QFN package are slightly different. The pins of DFN package are usually distributed on both sides of the package and the overall appearance is rectangular, while the pins of QFN package are distributed on all sides of the package and the overall appearance is square. DFN and QFN packaging have something in common, but they are also different. Customers choose the most suitable packaging products according to different application scenarios and requirements.