發(fā)布時(shí)間：2018-05-11 02:35

  本文選題：雙頻容性耦合等離子體 + 電負(fù)性氣體��； 參考：《大連理工大學(xué)》2015年博士論文

【摘要】：雙頻容性耦合等離子體(Dual-Frequency Capacitively Coupled Plasmas, DF-CCPs)能夠獨(dú)立控制轟擊到基片表面的離子通量和能量,從而可以緩解刻蝕過(guò)程中刻蝕速率與器件損傷的矛盾和減弱薄膜沉積過(guò)程中的充電效應(yīng),因而在國(guó)際上被廣泛地應(yīng)用到半導(dǎo)體芯片的刻蝕和沉積工藝中。電子密度及離子能量作為等離子體最基本的參數(shù),對(duì)于理解等離子體的特性及優(yōu)化工藝過(guò)程具有重要的意義。到目前為止,有關(guān)DF-CCPs的實(shí)驗(yàn)研究主要以Ar放電為主,而對(duì)于在實(shí)際刻蝕工藝中被大量使用的電負(fù)性氣體,像O2、 CF4, c-C4F8等,實(shí)驗(yàn)研究工作較少。本文從實(shí)驗(yàn)上系統(tǒng)地研究了在O2、Ar/O2、Ar/CF4、 Ar/O2/CF4放電中,控制變量(高頻功率、低頻頻率和功率、氣壓等)對(duì)電子密度和離子能量分布等的影響。同時(shí),采用了流體模型及PIC/MC (Particle-In-Cell and Monte Calro)模型與實(shí)驗(yàn)結(jié)果進(jìn)行對(duì)比驗(yàn)證。本論文研究對(duì)象大多是具有氧化性或腐蝕性的氣體,傳統(tǒng)的診斷手段(如,Langmuir探針)無(wú)法有效地使用,然而微波發(fā)卡探針和四極桿質(zhì)譜儀基本上不受腐蝕性氣體影響,可以較準(zhǔn)確地測(cè)量電子密度和離子能量分布。在第1章,簡(jiǎn)單地介紹了低溫等離子體在集成電路工業(yè)中的應(yīng)用、低溫射頻等離子體源、DF-CCP的研究進(jìn)展及熱點(diǎn)問(wèn)題,給出了本論文的研究?jī)?nèi)容安排。在第2章,簡(jiǎn)單地介紹了雙頻容性耦合放電裝置的關(guān)鍵參數(shù),詳細(xì)地介紹了實(shí)驗(yàn)中所使用的診斷手段(微波發(fā)卡探針、光探針、四極桿質(zhì)譜儀、電壓-電流探測(cè)器)的原理、結(jié)構(gòu)和使用方法。其中,微波發(fā)卡探針可以測(cè)量電子密度,光探針可以測(cè)量特定譜線(xiàn)的發(fā)光強(qiáng)度,四極桿質(zhì)譜儀能夠分辨出不同質(zhì)荷比的離子并給出相應(yīng)的離子能量分布,電壓-電流探測(cè)器可以測(cè)量電壓、電流、功率等電學(xué)參數(shù)。最后,簡(jiǎn)單介紹了本論文采用的數(shù)值模型,包括流體模型及PIC/MC模型。在第3章,基于上述的實(shí)驗(yàn)設(shè)備和診斷手段,系統(tǒng)地研究了在O2和Ar/O2放電中高頻功率、低頻功率、氣壓對(duì)電子密度的影響。研究表明：在O2放電中,電子密度主要由高頻功率決定,隨著高頻功率的增加電子密度線(xiàn)性增大；在較高高頻功率下,隨著低頻功率的增加電子密度減小,而當(dāng)高頻功率較低時(shí)電子密度會(huì)隨著低頻功率增加而增大；隨著氣壓的升高,電子密度先快速增大而后緩慢減��；Ar的添加導(dǎo)致電子密度的增大,但不影響電子密度隨控制變量的變化趨勢(shì)。同時(shí),采用了PIC/MC模擬對(duì)實(shí)驗(yàn)結(jié)果進(jìn)行驗(yàn)證,二者取得較好的一致性。在第4章,系統(tǒng)地研究了在Ar/O2放電中低頻頻率、低頻功率、氣壓等對(duì)離子能量分布的影響。研究表明：低頻頻率和低頻功率是影響離子能量分布的主要參數(shù),并且二者的作用相反,即隨著低頻頻率增大,能寬逐漸變窄,高能峰向著低能區(qū)移動(dòng),而隨著低頻功率的增大,能寬逐漸變寬,高能峰向著高能區(qū)移動(dòng)；氣壓的升高導(dǎo)致激烈的共振電荷交換碰撞,產(chǎn)生更多的低能電子。同時(shí),采用了PIC/MC模擬對(duì)部分實(shí)驗(yàn)結(jié)果進(jìn)行驗(yàn)證,二者給出相同的變化趨勢(shì),但在數(shù)值方面二者存在著差異,針對(duì)差異分析了可能的原因。在第5章,系統(tǒng)地研究了在Ar/CF4和Ar/O2/CF4放電中高頻功率、低頻功率、氣壓對(duì)電子密度和離子能量分布的影響。研究表明：在Ar/CF4放電中,電子密度主要由高頻功率決定,低頻功率影響很小,O2的添加會(huì)導(dǎo)致電子密度的下降但不會(huì)影響電子密度隨控制變量的變化趨勢(shì)；離子能量主要由低頻源(頻率和功率)決定,高頻功率對(duì)其影響較小,氣壓的升高會(huì)導(dǎo)致能量分布中低能離子的增多。在第6章,研究了在O2放電中驅(qū)動(dòng)頻率對(duì)電子密度的影響。在相同的輸入功率下,不同驅(qū)動(dòng)頻率的等離子體吸收功率不同,很大一部分輸入功率耗散在匹配網(wǎng)絡(luò),在100MHz下,損失的功率高達(dá)50%以上。在固定等離子體吸收功率的條件下,電子密度隨著頻率從13.56 MHz升高到40.68 MHz而增大,當(dāng)頻率進(jìn)一步從60 MHz升高到100 MHz時(shí),電子密度在2.6 Pa和13.3 Pa下呈現(xiàn)不同的變化趨勢(shì)。在固定極板電壓的條件下,電子密度隨驅(qū)動(dòng)頻率的增大先增大后減小,在40.68 MHz時(shí)達(dá)到最大值。在第7章中,給出了本論文的主要結(jié)論、創(chuàng)新點(diǎn)及未來(lái)的工作計(jì)劃。
[Abstract]:The dual frequency capacitive coupled plasma (Dual-Frequency Capacitively Coupled Plasmas, DF-CCPs) can independently control the ion flux and energy of the bombardment on the substrate surface, thus alleviating the contradiction between etching rate and device damage and reducing the charge effect in the process of thin film deposition, so it is widely used in the world. In the etching and deposition process of semiconductor chips, the electron density and ion energy are the most basic parameters of the plasma. It is of great significance to understand the characteristics of the plasma and optimize the process process. So far, the experimental research on DF-CCPs is mainly based on the Ar discharge, and it has been widely used in the actual etching process. Electronegative gases, such as O2, CF4, c-C4F8 and so on, have less experimental work. In this paper, the effects of control variables (high frequency power, low frequency frequency and power, pressure and so on) on the electron density and ion energy distribution in O2, Ar/O2, Ar/CF4, Ar/O2/CF4 discharge are systematically studied. The fluid model and PIC/MC (Particle-) are used. The In-Cell and Monte Calro) model is compared with the experimental results. Most of the objects in this paper are oxidizing or corrosive gases, and the traditional methods of diagnosis (such as Langmuir probes) can not be used effectively. However, the microwave hairpin probe and quadrupole mass spectrometer are not affected by corrosive gases, and can be more accurately measured. In the first chapter, the application of low temperature plasma in the integrated circuit industry, the research progress and hot issues of DF-CCP are briefly introduced. The research content of this paper is given. In the second chapter, the key parameters of the dual frequency capacitive coupling discharge device are briefly introduced. The principle, structure and using method of the diagnostic means (microwave hairpin probe, optical probe, quadrupole mass spectrometer, voltage current detector) used in the experiment are introduced in detail. In this method, the microwave hairpin probe can measure the electron density. The light probe can measure the luminous intensity of the specific line. The quadrupole mass spectrometer can distinguish the different mass charge. The corresponding ion energy distribution is given and the voltage current detector can measure the electrical parameters such as voltage, current and power. Finally, the numerical model used in this paper, including the fluid model and the PIC/MC model, is briefly introduced. In the third chapter, the O2 and Ar/O2 discharge based on the above experimental setup and diagnosis are systematically studied. The effect of high frequency power, low frequency power and pressure on electron density. The study shows that in O2 discharge, the electron density is mainly determined by high frequency power, and the electron density increases linearly with the increase of high frequency power; at high frequency power, the electron density decreases with the increase of low frequency power, while the electron density will be low when the high frequency power is low. With the increase of low frequency power, the electron density increases quickly and then decreases with the increase of the pressure. The addition of Ar leads to the increase of the electron density, but does not affect the change trend of the electron density with the control variable. At the same time, the PIC/MC simulation is used to verify the experimental results, and the two are in good agreement. In the fourth chapter, The influence of low frequency frequency, low frequency power and pressure on the ion energy distribution in Ar/O2 discharge is systematically studied. The study shows that low frequency and low frequency power are the main parameters affecting the ion energy distribution, and the effect of the two is opposite, that is, as the frequency increases, the energy is gradually narrowed, and the high energy peak moves toward the low energy region. With the increase of low frequency power, the energy width gradually widened and the high energy peak moved toward the high energy region; the increase of the air pressure led to the intense resonance charge exchange collision and more low-energy electrons. At the same time, the PIC/MC simulation was used to verify the results of some experiments. The two people gave the same trend of change, but there were differences between the two in numerical aspects. The possible reasons for the difference are analyzed. In the fifth chapter, the influence of high frequency power, low frequency power and pressure on the electron density and ion energy distribution in Ar/CF4 and Ar/O2/CF4 discharge is systematically studied. The study shows that in Ar/CF4 discharge, the electron density is mainly determined by high frequency power, low frequency power is small, and the addition of O2 leads to the density of electron density. The decrease of the degree of degree does not affect the change trend of the electron density with the control variable; the ion energy is mainly determined by the low frequency source (frequency and power), the high frequency power has little influence on it, the increase of the pressure will lead to the increase of the low energy ion in the energy distribution. In the sixth chapter, the influence of the driving frequency on the electron density in the O2 discharge is studied. Under the input power, the plasma absorption power of different driving frequencies is different. A large part of the input power is dissipated in the matched network. Under 100MHz, the loss power is up to 50%. Under the condition of fixed plasma absorption power, the electron density increases with the frequency from 13.56 MHz to 40.68 MHz, when the frequency is further from 60 M. When the Hz is raised to 100 MHz, the electron density varies under 2.6 Pa and 13.3 Pa. Under the condition of the fixed plate voltage, the electron density increases first and then decreases with the increase of the driving frequency, and reaches the maximum at 40.68 MHz. In the seventh chapter, the main conclusions, innovation and future work plan of this paper are given.

【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：O53
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本文編號(hào)：1872050