Radio Frequency Ion Source for Reactive Ion Beam Etching

已经开发了用于制造高速、高密度、集成电路的各种干法蚀刻工艺。最近对亚微米特征尺寸的要求对反应离子刻蚀和惰性离子束刻蚀等现有技术提出了更高的要求。反应离子束刻蚀(RIBE)最近已被证明与这些技术相比具有优势，因为它具有高精度的亚微米图形定义，便于快速刻蚀。然而，现有的离子束源设计包含了热离子电子发射器，这种发射器很容易被Ribe工艺中使用的气体损坏。这导致离子源寿命短，从而极大地限制了Ribe的实际应用。这项提议将试图通过开发一种廉价的射频离子源来克服这一问题，预计这种离子源对反应气体及其产品不敏感。将建立一个20-30厘米、无磁场的射频离子源实验系统，其中包括一个冷阴极放电点火器。等离子体产生实验将使用氧气和四氯化碳气体进行，射频频率最高可达14兆赫。离子发射的均匀性将在大约1 mA/cm的电流密度下进行测量和优化。

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 .