Plasma-Enhanced Atomic Layer Deposition and Simulation by CFD using H2/Ar Plasma - Effect of Tailored Voltage Waveforms

• Main Authors: Yang, Hsin-Han, 楊欣翰
• Other Authors: Chen, Gen-Shun
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/72y4pm

碩士 === 國立清華大學 === 工程與系統科學系 === 107 === Plasma plays an important role in semiconductor manufacturing process nowadays. As semiconductor component size getting smaller and smaller, it was currently widely used in some critical processes. PEALD, which can deposit thin film at the atomic level with high uniformity, employed H2/Ar plasma source in an indirect CCP chamber is mainly used in advance process for deposition of Ni silicide. This work introduced a 2D-fluid model including 9 reactive particles and 43 gas phase reaction for H2/Ar plasma simulation. The main purpose of this study aims to reduce ion bombardment to the film while increasing the number of H atom exposed to it. In this work, the simulation result showed the basic electric and physical properties of the plasma, such as electron density, electron temperature, potential power and particle density distribution. The time of one RF power cycle is too short to accelerate the ions or atoms to move. However, the result indicated that the density distribution of some ions and atom will vary in a RF power cycle. It turns out that because of the electron, the behaviors of particles will affect each other in a RF power cycle. It will be discussed and explained by the reaction mechanism for each reactive particle. On the other hand, in this work, TVWs(Tailored Voltage Waveforms) are applied on power electrode, TVWs consist of two equal-voltage sine waves, which are the fundamental frequency 13.56 MHz and the second harmonic frequency 27.12 MHz. Two waveforms generated by tuning the relative phase between two frequencies are defined V_0 and V_90 comparing with original waveform (13.56 MHz). The results indicated that 13.56 MHz and V_0 perform better than V_90 in both forming H atom and ion bombardment prevention. There is the highest H flux arrived to the substrate in 13.56 MHz, which is 2.77 times greater than V_0, showing that 13.56 MHz perform better than V_0 in production of film-forming particle. However, flux of H3+ ions ,which mainly cause ion bombardment to substrate, to the substrate of 13.56 MHz is 1.59 times higher than of V_0, indicating 13.56 MHz might cause more ion bombardment than V_0 do. This work defined H flux/H3+ flux ratio of substrate surface to clearly assess which the best waveform is. The result shows H flux/H3+ flux ratio of 13.56 MHz, V_0 and V_90 are about 30, 54 and 5, indicating that V_0 perform better in this process.