Radio Frequency Ion Source for Reactive Ion Beam Etching

为了制造高速、高密度的集成半导体电路，已经开发了多种干刻蚀工艺。近年来对亚微米特征尺寸的要求对现有的反应离子刻蚀和惰性离子束刻蚀技术提出了很大的要求。反应离子束蚀刻（RIBE）最近被证明提供了相对于这些技术的优势，通过促进高精度，亚微米模式定义的快速蚀刻。然而，现有的离子束源设计包含热离子电子发射器，很容易被RIBE处理中使用的气体损坏。这导致离子源寿命短，从而极大地限制了RIBE的实际应用。本提案将尝试通过开发一种廉价的射频离子源来克服这一问题，该离子源对反应性气体及其产物不敏感。一个实验，20-30厘米，无磁场，射频离子源系统将被构建，其中包括一个冷阴极放电点火器。等离子体生成实验将在射频频率高达14兆赫的氧气和四氯化碳气体中进行。离子发射均匀性将在电流密度约为1ma /cm时进行测量和优化。

A variety of dry etching processes have been developed for use in the manufacture of high speed, high density, integrated semiconductor circuits. The recent requirements for submicron feature dimensions have placed stressing demands on existing technologies such as reactive ion etching and inert ion beam etching. Reactive ion beam etching (RIBE) has recently been demonstrated to offer advantages relative to these technologies by facilitating rapid etching with highly precise, submicron pattern definition. However, available ion beam source designs incorporate thermionic electron emitters which are easily damaged by the gases used in RIBE processing. This results in short ion source lifetime, thereby greatly limiting the practical application RIBE. This proposal will attempt to overcome this problem by developing an inexpensive radio frequency ion source which is expected to be insensitive to reactive gases and their products. An experimental, 20-30 cm, magnetic-field-free, RF ion source system will be constructed which incorporates a cold cathode discharge igniter. Plasma generation experiments will be performed with oxygen and carbon tetrachloride gases at RF frequencies up to 14 MHz. Ion emission uniformity will be measured and optimized at current density of approximtely 1 mA/cm .