電容耦合電漿源(Capacitively coupled plasma (CCP) sources)近年來已經被廣泛的使用在材料製程中。本研究之主旨為探討雙頻(Dual frequency)空心陰極放電(hollow cathode discharge, HCD)效應增強之電容式耦合電漿源(HCD-CCP)之電漿特性與操作參數之關聯性，並分析其物理機制。研究方法為數值模擬分析，採用二維流體模型，使用氬氣(Argon)電漿，內容包含3個氣體粒子以及4條氣相反應。
本研究首先探討操作於27.12 MHz之射頻CCP放電中接地電極溝槽之HCD效應。模擬結果顯示，溝槽寬度應大於為兩倍鞘層厚度加上電子與中性粒子之平均自由徑，HCD效應明顯產生，此與文獻中之推論所示之 HCD 效應產生條件相符。模擬結果亦顯示置於接地電極之溝槽亦產生HCD效應，可調控徑向之電漿密度分布。本研究進一步探討溝槽尺寸與操作參數對 HCD 效應之影響，模擬結果顯示, HCD 效應隨溝槽深度/操作氣壓/功率與頻率等參數增加而上升。其中電漿放電機制分別為:當溝槽深度增加，將使得空心陰極放電體積增加，進而提升其中之電漿密度；隨著操作壓力提升，電子與中性粒子之間碰撞增加而減少平均自由徑，溝槽區電子密度提高；射頻功率增加，將提升電子密度造成鞘層厚度變薄；而射頻功率上升，電漿密度提升，鞘層厚度下降；上述之操作參數變化皆影響電漿特性，提升HCD效應。
在雙頻(dual-frequency, DF) HCD-CCP 之特性模擬分析方面，功率電極施加之射頻電壓頻率為27.12 MHz與2 MHz。首先探討CCP與HCD-CCP不同低頻電壓之影響，模擬結果顯示，CCP中，低頻電壓上升，離子能量分佈函數(Ion energy distribution function, IEDF)往高能區偏移而降低，離子能量(Ion energy)提升，而電子密度些微下降，顯示雙頻CCP在電子密度與離子能量獨力控制效果較佳；在HCD-CCP中，當提升低頻電壓，電子密度於溝槽區明顯增加，仍具有HCD效應，但相較於CCP之結果，由於電漿密度隨低頻電壓增加而下降使鞘層厚度增加，致使HCD效應降低趨勢。

Capacitively coupled plasma (CCP) sources have been widely used for material processing. The purpose of this study is to investigate the plasma characteristics and the parametric analysis of dual- frequency on HCD-CCP, and is comprehend physical mechanism. The research method is numerical simulation analysis, it adopts the two dimensional fluid model. The simulation model takes into account 3 gaseous species and 4 reactions for argon plasma.
One of study is investigated the hollow cathode discharge effect (HCD) of the trench at ground electrode by operating at 27.12 MHz with CCP discharged. The simulation results show that if the width of the trench is wider than the sum of twice the thickness of the plasma sheath and electron-neutral mean free path (2ds+λ), HCD obviously generates and this result corresponds with the conditions from the HCD in the literatures. Therefore, HCD generates at the trench of ground electrode and it can tune the distribution of radial plasma density. This study has further discussion for the effect of trench size and operating parameters on HCD. The simulation results show that HCD rises with the increase of the trench depth, operating pressure, power and frequency parameters etc. The plasma discharge mechanism: When the trench depth increases, the area of trench is increased and the electron density at position of trench is promoted; As the operating pressure rises, the collisions probability between electrons and neutral particles decreases and the mean free path drops with the increase of the electron density at the position of trench; When bumping the applied power up, increasing the electron density causes the sheath thickness to become thinner; Though driving frequency rises, the plasma density is promoted with the reduce of the sheath thickness. To sum up, the above simulation results influence the plasma characteristic and effectively improve the hollow cathode discharge.
In the simulation analysis of the characteristics of dual-frequency HCD-CCP, the dual radio frequency voltage of power electrode are 27.12 MHz and 2 MHz. In CCP, simulation analysis show that the low frequency voltage increases, Ion energy distribution function (IEDF) shifts to high energy level and drops; ion energy is promoted and the electron density depends slightly on the LF amplitude. Hence, the independently control effect in electron density and ion energy is better in dual frequency CCP; In HCD-CCP, the low frequency voltage increases with the electron density obviously enhanced in the position of trench and still has the HCD effect. However, compared with the results of CCP, the thickness of the sheath increases due to the plasma density decreases with the decrease of low frequency voltage, therefore, the HCD effect has a downward trend.

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