The System-level thermal solution is mainly about controlling the ambient temperature where the electronic equipment is located. The ambient temperature is an important boundary condition for the thermal analysis at the circuit board level.

There are three main thermal management designs.
1. Natural cooling: Electronic equipment generally adopts this cooling method. Thermal radiation can be propagated through a vacuum or through a gas with relatively little absorption. When there is a large temperature difference inside the electronic equipment, radiation heat exchange can be used for heat conduction.
2. Forced cooling: It includes air cooling and liquid cooling; air forced convection cooling technology reduces the volume of electronic equipment cooling system compared with natural cooling, making it have higher component density and higher hot spot temperature; liquid cooling mainly relies on the phase change principle. The phase change process is accompanied by the release and absorption of a large amount of heat. The phase change cooling can effectively control the temperature of electronic devices.
3. Heat pipe cooling: A heat pipe is a hollow tube with a sealed structure, which contains a liquid that transfers a large amount of heat when evaporating and a wick that brings the liquid back to the starting point when condensing. The whole process is completed without external power, without mechanical moving parts, without noise, and the design is extremely simple and effective, and the heat transfer is hundreds of times greater than that of solid metal.
Main designs: designs of metal electronic packaging housing, frame and base; designs of metal-ceramic composite electronic packaging housing, frame and base; designs of battery water-cooling plates; aerospace special VC structure heat dissipation design.

The Packaging-level thermal Solution is mainly aimed at the thermal design of electronic template and the PCB circuit board. It is closely related to the circuit design and structural design of the equipment. It’s about the selection of circuit board substrates.

Metal Matrix Ceramic Base Plate
1. Density is between 2.95-3.05g/ cm³;
2. The thermal expansion system (CTE) is between 6-9ppm/℃, and the thermal conductivity is 180-240(W/mK).
3. It has the adjustable volume fraction; Increasing the volume fraction of SiC can significantly reduce the thermal expansion coefficient.
4. With high thermal conductivity and specific stiffness；The surface can be plated with nickel, gold, silver, and copper with good plating performance.

Ceramic Base Plate
1. The CTE of the ceramic base plate is close to that of the silicon chip, which can save the use of Mo interlayer, also saving the labor and material cost.
2. With thinner welding layer and lower thermal resistance, the ceramic baseplate will improve the yield.
3. Excellent thermal conductivity makes the chip package very compact, so that the power density is greatly improved, and also the reliability of the system or device; The high Insulation Voltage ensures personnel and equipment safety.
4. Ultra-thin (0.25mm) ceramic substrates can replace BeO, non-toxic and environment friendly; It can also realize the new packaging methods, making products highly integrated and compact in size.
5. Large carrying capacity; 100A current continuously passes through the 1mm wide 0.3mm thick copper body, the temperature rise is about 17℃; Through the 2mm wide 0.3mm thick, the temperature rise is only about 5℃.
6. Low thermal resistance; Taking a 10×10mm ceramic substrate as an example, the thermal resistance of 0.63mm thickness is 0.31K/W, the thermal resistance of 0.38mm thickness is 0.19K/W, and the thermal resistance of 0.25mm thickness is 0.14K/W.

Metal Base Plate
Metal base plates have been increasingly used in the fields of hybrid integrated circuits, automobiles, high-power electrical equipment, and power supply equipment, due to its excellent performance of heat dissipation, machining, electromagnetic shielding, dimensional stability and magnetism etc., especially as a base substrate in LED packaging products.
1.The metal base plate can effectively dissipate heat, thereby alleviating the problem of thermal expansion and contraction of different components on the circuit board, and improving the durability and reliability of the whole machine and electronic equipment.
2.Many double-sided and multi-layer boards have high density and high power, and it is difficult to dissipate heat. Conventional circuit board substrates such as FR4 and CEM3 are poor conductors of heat. They are insulated between layers and cannot dissipate heat, resulting in high temperature failure of electronic components. Metal-based printed boards can solve this problem.
3.The size of the metal substrate is obviously much more stable than that of the insulating material.
4.Iron substrate, with shielding effect, can replace brittle ceramic substrate, replace components such as radiators, improve product heat resistance and physical properties, and reduce production costs and labor.

The electronic equipment is composed of components of various materials with different thermal expansion coefficients, such as silicon chips, silicon oxide insulating films, aluminum interconnect lines, metal lead frames and plastic packaging shells. Once the temperature changes, a compressive or tensile stress will be generated on the interface of different materials, thus resulting in thermal mismatch stress. The mismatch of thermal properties of materials is the internal cause of thermal stress, and the temperature change is the external. Component-level thermal design is to prevent device failure due to overheating or alternating temperature.


At present, most components use the third-generation electronic packaging materials represented by AlSiC, AlSi, diamond/copper and diamond/aluminum as the substrate.
1. Its CTE can be matched with dielectric substrates, ceramic ball arrays (BGA), low temperature sintered ceramic (LTCC) materials, and printed circuit boards, and it also has high thermal conductivity. High stiffness also provides protection for integrated circuit devices during assembly. The low density of such materials also improves device reliability when subjected to shock or vibration.
2. The geometry of the optoelectronic package is more complicated than that of the flip-chip cover, so more precise size control is required for the optical alignment pattern. All packages are molded and no additional processing is required for critical optical alignment parts. Hence lower cost compared to conventional packages. Thermal management in optoelectronic devices is also very important. Devices need to operate around room temperature, which requires materials with good heat dissipation properties to maintain temperature uniformity and optimize cooler performance. The tunable matched CTE values of the metal matrix composites can ensure the alignment of sensitive optics during operation, while also eliminating residual stresses that may be introduced during soldering or brazing assembly.