Carbon fiber reinforced polymer (CFRP) composite bone plates are widely used nowadays. Implants with a hydrophobic surface are highly recommended, and plasma treatment can be used to reduce surface wettability to improve biological functioning. This study reports the physical and chemical plasma etching of CFRP for controlled surface wettability. The plasma treatment was performed with a linear ion beam source, and optimized physical and chemical etching conditions were evaluated. The untreated specimens have a contact angle of 52o. It was observed that the maximum contact angle of 68o can be obtained by physical plasma etching whereas the minimum angle of 19o can be achieved by chemical plasma etching, which is an important task of this study to enhance adhesion of a thin diamond-like carbon film on CFRP on a coated composite bone plate.