Suppression of Partial Discharge in Package Insulation Under Square-Wave Voltage by Plasma-Enhanced Film Deposition

• Published in: International Conference on Electrical Materials and Power Equipment (Online) pp. 1 - 4
• Main Authors: Guan, Xiuhan, Zhang, Fengjie, Xu, Junhao, Cheng, Hongtu, Wang, Yalin, Zhu, Xi, Fang, Zhi
• Format: Conference Proceeding
• Language: English
• Published: IEEE 03.08.2025
• Subjects: Dielectric films; Discharges (electric); Electric fields; film deposition; Insulation; Multichip modules; package insulation; partial discharge suppression; Partial discharges; plasma; Plasmas; square-wave voltage; Stress; Switching circuits; Voltage control
• ISSN: 2996-3028
• DOI: 10.1109/ICEMPE66159.2025.11122997

The rapid development of power modules, characterized by high \mathrm{d} v / \text{dt} switching, subjects package insulation to severe electrical stress under square-wave voltage, leading to detrimental partial discharges (PD) at triple point (TP) region. This study introduces a precision atmospheric pressure micro-plasma jet ( \mu -APPJ) technique using HMDSO precursor to deposit Si-containing dielectric film at metal/insulation interface. By optimizing HMDSO volume fraction ( \phi_{\text {HMDso }} ), the effect of plasma treatment conditions on PD suppression at 5 \text{kHz} / 50 \% duty-cycle square-wave voltage is evaluated. The results show that Ar/HMDSO plasma-deposited films are effective in suppressing the PD intensity, but introduce an unanticipated PD phenomenon at the high-level stage. With the increase of HMDSO volume fraction, the maximum PD amplitude of the unpotted sample at \phi_{\text {HMDSO }}=0.24 \% decreased to 12.25 mV (84.6 % reduction) and the PD is completely suppressed in the high-level stage. The number of PDs of the potted sample is reduced by 56.1 %, with an average amplitude reduction of 53.9 %, and the breakdown voltage is increased to 17 kV. This technique provides a novel approach to improve the insulation reliability of power modules.