28 th ICPIG, July 15-20, 2007, Prague, Czech Republi Plasma Chemical Surface Functionalization of PTFE Sheet Through Atmospheric Pressure Plasma Liquid Deposition Approach N. Zettsu, H. Itoh, and K. Yamamura Research Center for Ultra-Precision Science and Technology, Graduate School of Engineering, Osaka University, Yamadaoka, Suita Osaka 565-0871, Japan Combining atmospheric pressure glow discharge technology with a unique precursor delivery system, Atmospheric Pressure Plasma Liquid Deposition, cam be used to chemically graft highly complex functionalities directly onto a variety of substrate. In this work we demonstrated facile surface activation of poly(tetrafluoroethylene) [PTFE] sheet through APPLD approach to design interface for subsequent copper deposition. We believe the plasmachemically deposited and fixed Cu(0) seeds allow to directly catalyze the initiation of the electroless copper deposition in absence of any additional surface activation steps such as SnCl 2 sensitization. The surface characterization was mainly evaluated by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. 1. Introduction Plasma enhanced surface modification is well known as a route to highly functionalized coatings, however applications have often been restricted to high value opportunities as plasma processes typically operate at reduced pressure with high capital cost and batch wise operation. Combining atmospheric pressure glow discharge technology with a unique precursor delivery system, Atmospheric Pressure Plasma Liquid Deposition (APPLD), opens a new window to coating process.[1] The APPLD, operating at atmospheric pressure and ambient temperature, allows the use of a wide range of liquid precursors delivering high coating rates onto flexible substrates. In this work, we demonstrated surface functionalization of poly(tetrafluoroethylene) [PTFE] sheet through APPLD approach to design interface for subsequent copper deposition. The ever increasing demand for miniaturization and increased signal speed have resulted in a constant quest for useful materials with very low dielectric constant to replace the glass fiber-epoxy composites currently in use. One of the most requirements for the fastest microelectronics of near future is the reduction of the signal interconnection delay time to a small fraction of the total switching delay time. One approach to achieve this goal is the use of multilayer device incorporating highly conductive metals and low capacitance dielectrics with dielectric constant of ~2.0. Poly(tetrafluoroethylene) is one of ideal materials for high frequency electronics applications due to its fine thermal stability, chemical inertness and low dielectric constant (2.1). [2] Due to its surface inertness, as obtained PTFE substrate fails to satisfy the adhesive strength against to various metals and semiconductors that many of the industry require. Pretreatment of the PTFE surface before metalization become key technology. A number of research groups demonstrated surface modification of PTFE surface for adhesion improvement through both physical and chemical approaches including ion beam processing, corona discharge, X-ray irradiation, plasma treatment, wet chemical etching, and graft polymerization.[3] Especially, ultraviolet (UV) light initialized copolymerization with a metal ion complexing polymer exhibited significant improvement of adhesive strength of electrolessly deposited copper (Cu) on PTFE surface.[4] Although graft copolymerization highly improved the adhesive strength, the tedious processing steps was required. Thermally or UV initiated grafting reactions generally operate in dagassed solvents. We demonstrated herein facile surface functionalization of PTFE sheet by means of APPLD treatment and subsequent electroless Cu plating in absence of SnCl 2 / PdCl 2 sensitization. We found that radiation with atmospheric He plasma to the PTFE sheet covered with a liquid thin film, containing both a Cu 2+ ion and metal ion complexing polymer, resulted in grafting and, formation and fixation of Cu(0) seeds on the PTFE sheet, simultaneously. 2. Experimental Section 2.1. Materials Poly(tetrafluoroethylene) sheet with 1.0mm thick was purchased from Nippon Valqua Industries Ltd. The PTFE sheets were cut into platelets with 20 x 20 mm 2 in area. The sheet was ultrasonically cleaned with acetone and pure water for 15 sec each. Poly(4-vinyl pyridine) (P4VP, Mw: 60K) and copper(II) acetate monohydrate (CuAc) were purchased from Sigma-Aldrich corporation, and Wako Pure Chemical Industries, Ltd., respectively.