By using thick photoresist AZ9260 and sputtered Ti film as masks, dry etching characteristics of benzocyclobutene (BCB), including etch rates, selectivities and sidewall profile, are investigated in CF4/O-2 and SF6/O-2 plasmas with various fluorine concentration, chamber pressure and RF power conditions, At 300 W and 50 mTorr, maximum etch rates of 0.7 and 0.6 mu m/min are achieved at 30% and 20% fluorine composition for CF4/O-2 and SF6/O-2 plasmas, respectively. At the same power and pressure conditions, the maximum selectivities of BCB over photoresist are determined as I for both plasmas, while the maximum selectivities of BCB over sputtered Ti are extracted as 13 for CF4/O-2 (30:70), and 20 for SF6/O-2 (20: 80) plasmas. For both plasmas, three-level Design of Experiment (DoE) technique was utilized to study the interaction between the RF power and chamber pressure in terms of their effects on the etching characteristics. The observation and characterization data may be leveraged as guidance for different BCB etching control as required by various applications. (c) 2005 Elsevier B.V. All rights reserved.