A Novel Focused Induction Heating Method For The Interconnection Between High-power Devices And Integrated Circuit Board

High-power devices are widely used in power supply, motor drive, medical treatment, and industrial automation. Hence, the interconnection of high-power devices to complicated circuit boards is critical. Due to the presence of large heat dissipation pins in high-power devices, there is a need for high energy input at localized solder joint locations during interconnection. However, there are relatively few localized heating processes suitable for such high-energy input, leading challenges on the interconnection of high-power devices with complex circuit boards. This work proposes a novel focused induction heating method (N-FIHM) combining external magnetizer and internal magnetizer to focus the magnetic field and increase the induction heating efficiency. Results showed that the N-FIHM can better focus the magnetic field at the solder joint position and increase the joint temperature. Compared the traditional induction heating method, the magnetic field density at the solder joint increases by a factor of 7, from 0.02 T to 0.14 T, and the temperature of the solder joint increases significantly by a factor of 6.9 (from 45 °C to 310 °C) with the same coil position and heating time.In addition, the study explores the influence mechanism of the structural parameters of the external tapered magnetizer on the magnetic field focusing and heating efficiency. The structural parameters include the distance between the inner and outer magnetizers, the wall thickness of the outer tapered magnetizer, the distance between the outer tapered magnetizer and the substrate, the height of the outer tapered magnetizer, and the inner diameter of the outer tapered magnetizer. It was found that the distance between inner and outer magnetizers has the greatest impact on heating efficiency. The solder joint temperature increases rapidly from the minimum value of 120 °C to the maximum value of 401 °C.