In-line ozone cleaning for plated ceramic substrates

Oxygen plasma ashing is commonly used to remove organic residues from surfaces, such as alumina substrates, after the plating process. An innovative cleaning method was developed in order to replace the oxygen plasma batch process by a continuous, in-line, process using ozone as the reactive gas. This paper describes the development and qualification of the ozone ashing process. Feasibility experiments and equipment design are briefly presented. Process parameters considered in the Design of Experiments and chosen methods to evaluate the efficiency of the process, along with results, are discussed. Qualification requirements as well as functional and reliability test results are also reviewed. An integrated approach was used throughout this project, taking into account possible substrate-assembly interactions while considering the need for evaluation methods representative of the actual manufacturing process. A discussion of this approach concludes the paper.