持续高功率磁控溅射技术高速制备挠性覆铜板Cu膜

Rapid Deposition of Flexible Copper Clad Laminate Used Cu Film by Continuous High Power Magnetron Sputtering

挠性覆铜板(FCCL)是电子信息领域的基础材料,随着电子产品高集成化、高密度化、高频化的发展,对具有低介电损耗特点的聚酰亚胺/铜(PI/Cu)双层覆铜板的需求越来越大。目前高端FCCL的生产中存在膜基结合力差、Cu致密度低、环境污染等问题。本文提出利用兼具高离化率、高沉积速率特点的持续高功率磁控溅射技术(C-HPMS),通过多步离子能量控制在PI表面实现了真空环境下的Cu膜制备,研究了溅射功率密度、沉积温度和基底偏压对Cu膜沉积速率、致密度、膜基结合力等性能的影响,发现用C-HPMS制备Cu膜,沉积速率可以高达1.72μm/min;Cu膜与PI结合牢固,刻蚀后通过胶带测试,结合力均在0.76~0.87 N/mm之间;与压延Cu膜、电镀Cu膜的结构对比,膜层致密,晶粒尺寸均在20 nm左右;电阻率低,2μm厚度时低至4.3×10-8Ω·m,优于电镀法和压延法制备的厚度8μm的Cu膜。

Flexible copper clad laminates(FCCL)are fundamental materials in electronic information field,especially the polyimide/Copper(PI/Cu)double layered FCCL is extensively required because of its low dielectric loss with the development in high integration,high density and high working frequency.However,the fabricating methods have shortages in film density,adhesion and environmental friendly.This article aims to develop a completely vacuum method to fabricate the Cu film on flexible PI by Continuous high power magnetron sputtering(C-HPMS)which is reported to has both high deposition and high ionization rate.The film qualities are sequentially studied depending on power density,substrate temperature and bias.The results show that C-HPMS can produce a high Cu deposition rate of 1.72μm/min and a dense Cu film with a diameter of 13.6~22.2 nm by extra substrate cooling.By the optimization of bias,a high adhesion of 0.76~0.87 N/mm between Cu film and the PI substrate is obtained.Compared with the rolled and electroplating copper films,the Cu film prepared by C-HPMS has obvious advantages in film density.Therefore,a lower electrical resistivity of 4.3×10-8Ωm can be achieved from a much thinner Cu film(2μm)than the rolled and electroplating copper films(about 8μm).