Novel Copper Paste for Low-Temperature Metallization Process
Authors: Urashima Kosuke, Noudou Takaaki, Yonekura Motoki, Akebi Ryuji, Yanaka Yuichi, Ejiri Yoshinori Company: Hitachi Chemical Co., Ltd. Date Published: 9/17/2017
Abstract: A novel Cu paste was developed by optimizing the average Cu particle size. Cu particles having an average particle size of 130 nm were found to be suitable for low-temperature metallization, suppressing oxidation. Cu wirings with Line/Space (L/S) = 150 µm/150 µm and L/S = 60 µm/60 µm were formed by screen printing and aerosol jet printing, respectively. The shear strength of the Cu wiring and LCP substrate interface exceeded the target shear strength (4 MPa) and the shear strength was maintained even after a high-temperature storage test (150 °C for 200 h). It was found that electroless Ni/Au (ENIG) can be applied to Cu wiring and the developed Cu paste can be used as a via connection material. The developed Cu paste is applicable to the fabrication of Cu wiring on two-dimensional (2D) and three-dimensional (3D) substrates.