High performance and reliable ultra-thin vapor chamber via an optimised second vacuuming and sealing process

Ultra-thin vapor chambers (UTVCs) have been widely used for cooling high-power electronics owing to their superior heat transfer properties. However, UTVCs, especially those with thicknesses below 0.4 mm, still face poor performance and unreliability problems. As a key processing technology, the second vacuuming and sealing process can significantly improve the heat transfer performance and reliability of UTVC; however, it has seldom been studied. In this study, a UTVC with a thickness of only 0.32 mm was developed, and an optimised second vacuuming and sealing process was proposed to obtain a high-performance and reliable UTVC. The UTVC, prepared via resistance welding sealing, demonstrates reliable performance, operating effectively at high temperatures (240 ℃) and internal pressures exceeding 3.3 MPa, without leakage. Optimising second vacuuming parameters effectively removes most non-condensable gas, thereby enhancing the heat transfer performance of UTVCs. UTVC proposed with the vacuuming time of 35 s, vacuuming temperature of 90 ℃, and gas collecting section length of 20 mm exhibits a thermal resistance of 1.701 W/℃ at a heat load of 3 W. This study benefits the design of a second vacuuming and sealing process for UTVC with thickness less than 0.4 mm, further promoting its industrial applications. © 2023 Elsevier Ltd