Different types of ceramic pcb
Ceramic PCB is widely used in power electronics, electronic packaging, hybrid microelectronics and multi-chip modules due to its excellent thermal conductivity and air tightness. But not everyone is clear about the classification. Many manufacturers think ceramic PCBs are expensive and fragile as soon as they hear about ceramic PCBs. Yes, this is indeed a shortcoming of ceramic PCBs, but not all ceramic PCBs are like this. Today we will tell you about the different types of ceramic PCBs.
Al2O3 ceramic PCB
Al2O3 ceramic PCB ( alumina ceramic PCB) refers to various ceramic PCBs with Al2O3 as the main raw material and an Al2O3 content of more than 75%. It has a rich source of raw materials, with advantages of low price, high mechanical strength and hardness, good insulation performance, good heat shock resistance, good chemical resistance, high dimensional accuracy, and good adhesion to metals. It is a ceramic substrate material with good comprehensive performance. Currently used Al2O3 ceramic substrates, the content of Al2O3 accounts for 85% to 99.5%. Among them, 96% Al2O3 ceramic PCB is widely used in the production of thick film circuit substrates and chip devices. The thermal conductivity of Al2O3 at room temperature is 29W/(m·K), which is close to the thermal conductivity of steel; with the increase of Al2O3 content, the electrical insulation performance and thermal conductivity of Al2O3 ceramic PCB will increase, but At the same time, it will also lead to an increase in the firing temperature, an increase in energy consumption, a large loss of kiln furniture, and an increase in manufacturing costs.
SiC ceramic PCB
The thermal conductivity of SiC ceramic PCB is very high, 100~490W/(m·K) at room temperature, and it is related to the purity of SiC crystals. The higher the purity, the greater the thermal conductivity; the oxidation resistance is good, and the decomposition temperature is above 2500℃, it can still be used at 1600℃ in an oxidizing atmosphere; the coefficient of thermal expansion is also low, and it is close to Si, with good electrical insulation performance; SiC has a Mohs hardness of 9.75, second only to diamond and cubic BN, and has high mechanical strength. SiC ceramics have strong covalent bond characteristics and are difficult to sinter. Usually, a small amount of boron or aluminum oxide is added as a sintering aid to increase the density. Experiments show that beryllium, boron, aluminum and their compounds are the most effective additives, which can make SiC ceramics denser than 98%.
BeO ceramic PCB
BeO has a brazine structure, in which oxygen ions are arranged in a hexagonal close-packed manner to form a hexagonal lattice. The general oxide is usually an ionic compound, but BeO has a strong covalent bond and an average molecular weight of only 12. Because of its good electrical properties, luminescence and photochemical properties, high mechanical strength, low dielectric loss, etc, it become one of the materials that people pay attention to.
AlN ceramic PCB
AlN ceramic PCB (aluminum nitride ceramic) is a new type of high thermal conductivity ceramic packaging material. It has been extensively studied in the 1990s and gradually developed. It is currently generally considered to be a promising electronic ceramic packaging PCB. AlN material has high thermal conductivity, excellent dielectric properties, high electrical insulation strength, stable chemical properties, strong corrosion resistance, and good mechanical properties. In particular, its thermal expansion coefficient matches with silicon, which makes it an ideal semiconductor packaging substrate materials and have been widely used in integrated circuits, microwave power devices, millimeter-wave packaging, high-temperature electronic packaging and other fields.