Preparation of three-dimensional ceramic substrate by multiple electroforming for UV-LED hermetic packaging

In this work, preparation of three-dimensional direct plated copper (3DPC) ceramic substrate was proposed based on multiple lithography and electroforming. Firstly, the effects of current density, stirring speed and bath temperature on electrodeposition rate and residual stress were investigated. An optimal combination of parameters for high electrodeposition rate and low residual stress was the current density of 4 A/dm(2), the stirring speed of 1000 rpm, and the bath temperature of 50 degrees C. Secondly, 3DPC ceramic substrate with 0.5 mm nickel dam was prepared through 4 times lithography and electroforming. Finally, the reliability of 3DPC substrate was evaluated by helium leak rate and bonding strength between the electroforming dam and planar DPC substrate during thermal cycle test. The 3DPC substrate exhibited excellent hermeticity and high bonding strength even after 30 thermal cycles. The UV-LED module packaged using 3DPC substrate and quartz glass exhibited excellent hermeticity and high light power. The above results suggested that 3DPC substrate prepared through multiple lithography and electroforming could be a promising candidate for UV-LED hermetic packaging.