Electrostatic Discharge Analysis under Ultra clean environment

本项目是对静电充放电问题的基础性研究，尤其是与洁净空气条件有关的问题。提出了两种静电电荷分布的测量方法。一种是亚微米尺度的表面电荷分布分析，利用压电式扫描台和静电力探测器进行光学干涉测距。扫描装置运行良好，但由于手工设备的不稳定，测力仪的灵敏度不足以检测局部电荷。原理本身是可能的，但需要精细的机械技术。首次利用聚偏氟乙烯(PVDF)压电聚合物薄膜作为压力发生器，研制了一种基于纳秒压力脉冲的空间电荷分布测量系统。该系统可以检测等离子体表面处理对稳定聚合物薄膜的影响差异。然而，由于该系统的最终分辨率仅为7微米，因此无法观测到薄介质膜中的真实空间电荷。通过电荷分布分析、热刺激放电电流分析(TSDC)、水滴接触角等测试手段，对低压等离子体处理聚合物薄膜的抗静电处理效果进行了测试。他们可以在一周内检测到这样的治疗效果和腐烂。等离子体的环境气体效应并不像估计的那么大。利用静电感应探头和磁性探头(电磁波探测)对带电薄膜上的静电放电现象进行了精确的分析。作为项目的结果，分析了静电荷电与表面状态的相关性。

This project is a fundamental research of electrostatic charging and discharge problems, especially related with clean air conditions. Two electrostatic charge distribution measuring methods were proposed. One is surface charge distribution analysis in sub-micrometer scale, by using a piezoelectric scanning stage and an electrostatic force detector with optical interferometric distance measurement. The scanning unit operated good but the sensitivity of the force detector was not enough to detect localized charge because of the instability of a hand-made equipment. The principle itself is possible, but fine mechanical technology is requested. A space charge distribution measuring system by using nano second pressure pulse was newly developed where a piezoelectric polymer film of PVDF was first used as pressure generator. The sysem could detect the difference of plasma surface processing effect on stable polymer films. However, the real space charge in a thin dielectric film could not observed by that system because the final resolution of the sytem was only 7 micrometer. As anti-static process, surface treatment effects of a polymer film by low pressure plasma processing were tested by charge distribution analysis, thermally stimulated discharge current analysis (TSDC), contact angle of water droplet and others. They could detect such treatment effects and decay of them during a week. Environmental gas effect of plasma was not so large as estimated. Electrostatic discharge phenomena on a charged thin film was precisely analyzed by using electronstatic induction probe and magnetic probe (electromagnetic wave detection). Correlation between electrostatic charging and surface state was analyzed as a result of the project.