(DBC Ceramic Substrate Produced by Wintrustek)
Direct Bonded Copper (DBC) ceramic substrates are a new type of composite material in which copper metal is coated on a highly insulating alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate. The surface metallization technology of alumina and aluminum nitride ceramic substrates is almost the same. Taking the Al2O3 ceramic substrate as an example, the Cu copper foil is directly welded to the alumina substrate by heating the ceramic substrate in a nitrogen atmosphere N2 containing oxygen.
Environmental heating at high temperatures (1065–1085) causes the copper metal to oxidize, diffuse, and melt ceramic eutectic, which bonds the copper and the ceramic substrate and creates a ceramic composite metal substrate; then prepare the line substrate by etching method according to the line design exposure film development. Mainly used in the packaging of power semiconductor modules, refrigerators and high temperature seals.
Circuit boards of computers and low-power home appliances typically use metal and organic substrates; however, ceramic substrate materials with better thermal properties, such as silicon nitride, aluminum nitride, and alumina, are required for high-voltage, high-current applications, such as power modules, solar inverters, and motor controllers.
The DBC substrate in power electronic module technology is mainly a variety of chips (IGBT chips, diode chips, resistors, SiC chips, etc.), the DBC substrate through the copper coating surface, to complete the chip part of the connection pole or connecting surface of the connection, the function is similar to that of the PCB substrate. The DBC substrate has good insulating properties, good heat dissipation performance, low thermal resistance and a matched expansion coefficient.
The DBC substrate has the following outstanding features: good insulation performance, good heat dissipation performance, low thermal resistance coefficient, matching expansion coefficient, good mechanical properties and good soldering performance.
1. Good insulating performance. Using the DBC substrate as a chip support effectively separates the chip from the module's heat dissipation baseplate, the DBC substrate in the middle of the Al2O3 ceramic layer or AlN ceramic layer effectively improves the module's insulating capacity (ceramic layer insulation voltage > 2.5KV).
2. Excellent thermal conductivity, the DBC substrate has an excellent thermal conductivity with of 20-260W/mK,IGBT module in the process of operation, the chip surface will generate a large amount of heat that can be effectively transferred through the DBC substrate to the thermal base plate of the module, then through the thermal conductive silicon on the base plate to the heat sink, to complete the overall heat flow of the module.
3. Outstanding electrical conductivity. Since copper is a highly conductive metal, electrical signals can be carried with little resistance thanks to the direct link between the copper and substrate. Because of this, DBC is ideally suited for use in high-speed electrical equipment that need to transmit data quickly and reliably, including computers and servers.
4. The expansion coefficient of the DBC substrate is similar to that of the chip.The DBC substrate's coefficient of expansion is similar to that of silicon (the chip's main material is silicon) (7.1ppm/K), which won't cause stress damage to the chip, and the DBC substrate's peel strength >20N/mm2. Besides, it also has good mechanical properties and corrosion resistance. DBC is not easy to deform, and can be used over a wide temperature range.
5. Welding performance is good. The welding performance of the DBC substrate is good. The soldering void ratio is less than 5%, and the DBC substrate has a thicker copper layer that can withstand a very high current load. At the same cross-section, it typically requires only 12% of the PCB's conductive width, then can transmit more power in a unit volume to improve system and equipment reliability. Due to their excellent performance, DBC substrates are widely used in the preparation of various types of high-power semiconductors, particularly IGBT packaging materials.
6. Highly durable and long-lasting. In military and aerospace applications where electronic equipment must be able to survive extreme conditions, the direct link between the copper and substrate produces a strong, rigid structure that can withstand handling and hostile environments.
