Plated Copper on Thick Film Ceramic Substrates and Their Packaging Applications for Deep-Ultraviolet LEDs

Direct plated copper (DPC) ceramic substrates are gradually increasing their application scope in power electronic device packaging due to their advantages of excellent thermal conductivity and high integration density (vertical interconnection). However, the working reliability of DPC ceramic substrates under high temperatures (above
$300\ ^{\circ}\mathrm{C}$
) is far from satisfactory, behaving as low bonding strength at the interface of metal layer and ceramic. In order to fix this problem, a new style of plated copper on thick film (PCTF) ceramic substrate was proposed for this work. The shear strength at the interface of the Ag layer and ceramic substrate is up to 80 MPa, which is 60% higher than that of DPC substrate, and the tensile strength is above 32.2 MPa, which is 165% higher than that of DPC substrates. In addition, the shear strength between the Cu and Ag layers is up to 88.5 MPa, with a tensile strength of more than 23.44 MPa. Moreover, packaging DUV LEDs with PCTF substrates in our experiments. As a result, the packaged DUV LED presented good optical and thermal properties. The PCTF ceramic substrate designed in this work showed great potential application in high-power device packaging.