The key technology of silicon carbide power device packaging

Silicon carbide (SiC) power devices are becoming a research hotspot in the field of power electronics because of their excellent performance in high temperature, high frequency and high efficiency. In order to give full play to the performance of silicon carbide power devices, the development of high-performance packaging technology is the key. In this paper, the latest development and application of low spurious inductance package technology, high temperature package technology and multi-function integrated package technology are discussed.

1, low stray inductance packaging technology

Low spurious inductance packaging is one of the key technologies to improve the high frequency performance of silicon carbide power devices. In high frequency applications, stray inductance can lead to an increase in switching losses, which affects the efficiency and reliability of the device. Therefore, researchers are committed to developing new packaging structures to reduce the stray inductance of the package.

Single-tube flip patch package: Using the BGA package technology for reference, the single-tube flip patch package is used to turn the back electrode of the to the same plane position of the front electrode through the metal connector, thereby eliminating the metal bonding line, reducing the volume, and improving the on-resistance.

DBC+PCB hybrid package: Combined with DBC process and PCB board, the use of metal bonding wire to connect the upper surface of the chip to the PCB board, control the converter loop between the PCB layers, reduce the current loop area, effectively reduce stray inductance parameters, improve performance.

Chip front plane interconnection package: The plane interconnection connection method, such as terminal direct connection welding method, realizes the chip front connection, reduces the current loop, improves the temperature cycle characteristics and reliability.

An effective method is to use package layout optimization design. For example, using multiple thick film copper wires instead of conventional metal leads can significantly reduce stray inductance. In addition, the use of integrated conducting layer (ICL) technology can also effectively reduce stray inductance by forming electrical connections directly inside the package.

2, high temperature packaging technology

Silicon carbide power devices can work at up to 600 ° C, and traditional packaging materials and technologies often cannot meet this requirement. Therefore, the development of high temperature packaging technology is very important.

Flexible PCB board combined with sintered silver process: the flexible PCB board combined with sintered silver process is used for packaging, replacing the bonding line, achieving electrical connection, effectively reducing stray inductance parameters, reducing volume, and improving power density.

Embedded package: The chip is placed in a ceramic positioning slot, the gap is filled with insulating media, and the metal copper is covered to achieve electrode connection, reduce the interlayer thermal stress of the module at high temperature, and improve the positive and negative characteristics.

The key of high temperature packaging technology is to select materials that can withstand high temperatures and have good thermal stability. For example, the use of cermet (MMC) or ceramic matrix composites as packaging substrates can provide excellent thermal stability and thermal conductivity. At the same time, the use of high-temperature eutectic metals or high-temperature conductive adhesives as solder or adhesives is another key technology to achieve high-temperature packaging.

3, multi-function integrated packaging technology

With the development of power electronic systems towards miniaturization and integration, multifunctional integrated packaging technology has become a trend. This technology not only requires the package to provide electrical connectivity and thermal management, but also expects to integrate more functions such as sensing, protection and heat dissipation.

Planar direct connection package: Eliminate metal bonding lines, expand the current loop from the DBC board plane layout to the interlayer layout of the upper and lower planes of the chip, reduce the loop area, and achieve low stray inductance parameters.

Double-sided heat dissipation package and three-dimensional package: by changing the packaging method, to achieve better heat dissipation effect and improve power density.

One way to realize multifunctional integrated package is to adopt system level package (SiP) technology. By integrating multiple devices and functional modules in the same package, the system size can be effectively reduced and the system performance can be improved. In addition, the use of embedded technology to embed sensors or other functional components directly into the packaging material is also an effective way to achieve multi-functional integrated packaging.

Conclusion

With the continuous expansion of the application field of silicon carbide power devices, the research and development of packaging technology becomes particularly important. Low stray inductance packaging technology, high temperature packaging technology and multi-function integrated packaging technology are the three key technology directions in the field of silicon carbide power device packaging. Through continuous technological innovation and material development, these packaging technologies are expected to further improve the performance and reliability of silicon carbide power devices and promote the development of power electronics technology.