Three-dimensional ceramic substrate prepared by repeated lithography and electroforming

In this work, three dimensional direct plated copper (3DPC) ceramic substrate prepared by repeated ultraviolet (UV) depth lithography and electroforming is proposed. The effects of different electroforming parameters including current density, stirring speed, and temperature were evaluated by internal stress and electroforming rate using a L₉(3⁴) orthogonal experiment. Range analysis and analysis of variance (ANOVA) were employed to estimate the contribution of each factor to the overall response. The optimal electrodeposition parameters were the current density of 4 ASD, the stirring speed of 1200 rpm, and the temperature of 50°C. Furthermore, the microstructure, hermeticity, and thermal reliability of 3DPC substrate were researched. The results showed the 3DPC substrate had excellent hermeticity and the strong bonding strength between dam and flat DPC substrate even after 30 thermal cycles. The above results demonstrated that 3DPC substrate could be considered as a reliable substrate for UV-LED hermetic packaging.