Thin film structuring on LTCC

With the increase of transmission frequencies in telecommunications, the requirements for structural resolution and accuracy of substrates for high frequency circuits rise as well. Through its material properties, low temperature cofired ceramics (LTCC) are well suited to these special applications. However, the classical thick film structuring methods reach their limits with these requirements. Thin film structuring is an alternative. In this work 15 mum lines and 25 mum spaces are demonstrated in a 120 nm thin Ti/Pt metallization by means of lift-off patterning. By adding copper galvanically to a sputtered seed layer a film thickness up to 6 mum can be reached. Using this semiadditive process, 60 mum lines and 25 mum spaces are realized. The reliability of SMT components soldered onto the film is analyzed after temperature cycling.