This paper reviews recent work at DuPont to develop high performance Tl 2Ba 2CaCu 2O 8 and YBa 2Cu 3O 7 thin films for microwave and electronic device applications. The YBa 2Cu 3O 7 thin films are produced by off-axis magnetron sputtering onto radiatively heated substrates and have surface roughness levels of less than 1 nm over 2 in. diameter wafers as determined by atomic force microscopy. Double-sided Tl 2Ba 2CaCu 2O 8 films are produced on 3 in. diameter CeO 2 buffered sapphire substrates with excellent uniformity of structural and electrical properties. These films have low microwave surface resistance up to high microwave power levels. We also report on the establishment of a Six Sigma manufacturing capability for Tl 2Ba 2CaCu 2O 8 films. These films are used to fabricate a compact high performance eight-pole bandpass filter operating at 1.85 GHz and 80 K.