Measurements of electron density and electron temperature with plasma absorption probe and its application to deposited plasmas

近年来，人们对高性能LSI电子器件进行了研究，以提高性能、计算速度和功耗。为了实现这一问题，已经开发了特征尺寸小于~ 100nm的微加工和用于改善配电线路信号延迟的低k材料。等离子体加工已广泛应用于微细加工和低k薄膜的形成，但仍有许多问题有待解决。了解等离子体的性质和精确控制等离子体适合所需的过程是必需的。在这项工作中，等离子体吸收探针使我们能够测量电子密度，甚至在绝缘聚合物沉积的污染条件下，改进到测量电子温度的重要参数，以表征等离子体。我们还将探针应用于CVD等离子体低k膜形成的诊断，并获得了改进材料工艺的基础数据。探针天线周围的护套对探针测量的吸收频率有更多的影响，护套厚度是德拜长度的几倍，是电子密度和电子温度的函数。因此，当测量吸收频率时，两个表面波吸收探针对鞘层厚度的依赖性不同，可以同时得到电子密度和电子温度。探针的天线直径对电子密度与电子温度的关系有显著影响，并且随着天线直径的增大，满足测量吸收频率的电子密度不再受电子温度的影响。两种探针对满意密度的温度依赖性不同，有利于准确测定密度和温度。因此，不同天线直径的探头更适合于精确测量。最后，电子密度和电子的精度几乎与传统的朗缪尔探针相同。探针揭示了用于低k薄膜沉积的窄间隙CVD等离子体系统的以下特征。(1)电子密度及其径向分布在很大程度上取决于放电功率和操作压力等条件，并且电子密度的径向分布与12英寸直径上的沉积速率之间存在相关性。硅晶片。(2)电子温度随着总操作压力的增加以及母体物质气体的一部分的增加而降低。Xe的加入对降低电子温度也有一定的作用。然而，没有明显的径向分布。作为衍生结果，探针系统也应用于其他等离子体系统的材料加工，并对其等离子体诊断有用。少

Recently, high performance LSI electronic devices has been studied to improve capability, calculation speed and power consumption. To achieve this issue, microfabrication with a feature size less than 〜100 nm and low-k materials for improvement of signal delay at distribution lines have been developed. Plasma processing has been widely used for the microfabrication and the low-k film formation, however there are still various problems to be solved. Understanding of plasma properties and precise control of the plasma suitable for desired process have been requred.In this work, plasma absorption probes which enable us to measure electron density even under soiled conditions of insulated polymer deposition were improved to measure electron temperature of important parameters to characterize the plasma. We also applied the probe to diagnostics of CVD plasmas for the low-k film formation, and fundamental data to improve the materials process were obtained.A sheath around the probe antenna a … More ffects on an absorption frequency measured with the probe, and sheath thickness is given by a several times of Debye length as a function of electron density and electron temperature. Therefore, when absorption frequencies are measured two surface wave absorption probes having different dependence on the sheath thickness, both of electron density and electron temperature can be simultaneously obtained. An antenna diameter of the probe significantly affected on the relation between the electron density and electron temperature, and the electron density satisfying the measured absorption frequency became independent of electron temperature as the antenna diameter increased. The different temperature dependence of the satisfying density between the two probes was preferable to accurately determine the density and the temperature. Therefore, the probes with much different antenna diameter were preferable to achieve accurate measurements. Finally, electron density and electron was available with the almost same accuracy of a conventional Langmuir probe.The probe revealed the following characteristics of a narrow gap CVD plasma system for low-k film deposition. (1)An electron density as well as its radial profile significantly depended on conditions such as discharge powers and operating pressures, and a correlation between radial profiles of the electron density and a deposition rate over a 12-inch-diam. silicon wafer. (2)An electron temperature decreased with an increase in the total operating pressure as well as a fraction of parent material gases. Xe addition was also effective for reduction of the electron temperature. However significant radial profile was not clearly observed.As derivative results, the probe system was also applied to other plasma systems for materials processing, and useful for their plasma diagnostics. Less