本文選題：Cu-W(Mo + Nb)復(fù)合薄膜��； 參考：《昆明理工大學(xué)》2016年博士論文

【摘要】：Cu薄膜具有良好的導(dǎo)電性、電遷移抗性及塑韌性,被廣泛用于微電子和微機(jī)械領(lǐng)域。但因其粘附性差、強(qiáng)度和硬度不高,因此Cu薄膜的改性成為必然。難熔金屬與銅在性質(zhì)上有互補(bǔ)性,且銅-難熔金屬?gòu)?fù)合薄膜常呈現(xiàn)特殊結(jié)構(gòu)及優(yōu)良的綜合性能。本文選擇Cu-W、Cu-Mo及Cu-Nb三個(gè)難混溶體系作研究對(duì)象,通過(guò)正交試驗(yàn)優(yōu)化工藝,采用磁控濺射方法,以組合靶共濺射成功制備了寬成分Cu-W.Cu-Mo及Cu-Nb復(fù)合薄膜,并用單質(zhì)靶交替沉積制備Cu/W納米多層膜。通過(guò)結(jié)構(gòu)與性能分析測(cè)試,研究W、Mo及Nb添加量對(duì)Cu復(fù)合薄膜結(jié)構(gòu)與性能及熱穩(wěn)定性的影響,考察Cu/W納米多層膜結(jié)構(gòu)與性能與調(diào)制參數(shù)的關(guān)系。這些研究不僅為銅-難熔金屬薄膜的應(yīng)用提供了實(shí)驗(yàn)依據(jù)和重要支持,而且對(duì)新穎結(jié)構(gòu)-功能型薄膜的設(shè)計(jì)和研發(fā)深具指導(dǎo)意義。提出了合理的評(píng)價(jià)指標(biāo)優(yōu)化工藝,即靶功率密度PD為8 W/cm2、濺射氣壓P為2 Pa、靶基距Drs為140 mm。統(tǒng)一用該工藝制備薄膜,為探討組元含量的影響規(guī)律提供了保證。自行設(shè)計(jì)了鑲嵌和疊加型組合靶,調(diào)整靶面積分?jǐn)?shù)即能有效控制成分,工藝簡(jiǎn)單且穩(wěn)定性和重復(fù)性好,為銅基復(fù)合薄膜的制備提供了一條新路徑。利用磁控濺射非平衡技術(shù),制備出了具有亞穩(wěn)和非晶結(jié)構(gòu)的Cu復(fù)合薄膜,其結(jié)構(gòu)與W、Mo及Nb含量有關(guān)：(1)在W、Mo及Nb低含量區(qū)(含(2.12～16.19)at.%W、 (2.19～15.12)at.%Mo及(1.16～23.43)at.%Nb),復(fù)合薄膜呈現(xiàn)亞穩(wěn)準(zhǔn)混溶態(tài)均質(zhì)化結(jié)構(gòu),存在fcc Cu(W).Cu(Mo)及Cu(Nb)亞穩(wěn)準(zhǔn)固溶體。(2)在中間含量區(qū)(含(24.65～38.2)at.%W.(20.26～35.15)at.%Mo及(35.32～48.1)at.%Nb),Cu-W和Cu-Mo膜呈亞穩(wěn)準(zhǔn)混溶態(tài)高度均質(zhì)化結(jié)構(gòu),分別存在(fcc Cu(W)+bcc W(Cu)).(fcc Cu(Mo)+bcc Mo(Cu))兩種亞穩(wěn)準(zhǔn)固溶體；Cu-Nb膜則為非晶Nb與晶態(tài)Cu混合結(jié)構(gòu)。(3)在高含量區(qū)(含(53.14～55.92)at.%W.(58.6-74.91)at.%Mo及(53.36～60.4)at.%Nb)),Cu-W和Cu-Mo膜也呈亞穩(wěn)準(zhǔn)混溶均質(zhì)化結(jié)構(gòu),并存在bcc W(Cu)和bcc Mo(Cu)亞穩(wěn)準(zhǔn)固溶體；Cu-Nb膜為完整非晶結(jié)構(gòu)。適量添加W、Mo及Nb可細(xì)化Cu復(fù)合薄膜的晶粒,并提高薄膜的表面光潔度：隨含量增加,晶粒尺寸逐漸減至小于4 nm,RMS值低達(dá)1.93 nm。這是因W、Mo、Nb原子形核率高擴(kuò)散率低,均勻彌散的核心可有效阻止Cu原子的擴(kuò)散遷移。含W、Mo及Nb的Cu復(fù)合薄膜存在102MPa量級(jí)的本征應(yīng)力,處于彈性壓應(yīng)力狀態(tài)。Cu復(fù)合薄膜電學(xué)性能和力學(xué)性能也與W、Mo及Nb含量有關(guān)：隨含量增加,Cu復(fù)合薄膜的電阻率ρ、屈服強(qiáng)度σ0.2、彈性模量E及硬度H逐漸增加,裂紋萌生臨界應(yīng)變8。和摩擦系數(shù)μk逐漸減小。高W、Mo含量的薄膜ρ、σ0.2及εc值減小,其余值增加；中、高Nb含量的Cu-Nb膜ρ和μk值明顯增加,其余值均降低。電學(xué)和力學(xué)性能的這種變化均與結(jié)構(gòu)變化密切相關(guān)�？傮w上,Cu-Nb膜電阻率最高而Cu-W膜最低,Cu-Nb膜彈性模量和硬度最低,體現(xiàn)了組元本征性質(zhì)的影響。Cu-2.12at.%W膜電阻率最低(11.4 μΩ·cm), Cu-35.15at.%Mo膜屈服強(qiáng)度最高(1.302 GPa)而摩擦系數(shù)最低(0.089), Cu-1.16at.%Nb膜裂紋萌生臨界應(yīng)變最大(1.95%), Cu-74.91at.%Mo膜彈性模量和硬度最高(分別為168.85和9.19 GPa)。添W、Mo及Nb明顯影響Cu復(fù)合薄膜的膜基結(jié)合力,結(jié)合力隨其含量增加先增后減,Cu-38.2at.%W膜結(jié)合力最強(qiáng)(31.07 N)。熱處理使Cu復(fù)合薄膜結(jié)構(gòu)發(fā)生不同程度的改變。200～400℃的退火通常只發(fā)生回復(fù)和初始再結(jié)晶；臨界退火溫度為650℃,中、高W、Mo及Nb含量的復(fù)合薄膜分別發(fā)生相分離及晶化轉(zhuǎn)變,形成(富Cu+富W、Mo及Nb)兩相并存結(jié)構(gòu)。退火溫度為650℃時(shí),隨退火時(shí)間延長(zhǎng),相分離更為徹底而兩相結(jié)構(gòu)趨于完整。退火時(shí)Cu復(fù)合薄膜應(yīng)變弛豫并減弱本征壓應(yīng)力。熱穩(wěn)定性評(píng)估表明Cu復(fù)合薄膜結(jié)構(gòu)基本穩(wěn)定的溫度上限約在400～650℃范圍。退火的Cu復(fù)合薄膜形貌明顯改變,出現(xiàn)凸出表面的Cu偏聚粒子,表面粗糙度顯著增加。一些偏聚粒子表觀形狀為六邊形或準(zhǔn)對(duì)稱(chēng)八邊形,歸因于其結(jié)構(gòu)為能量最低的截角八面體。退火改變薄膜力學(xué)和電學(xué)性能,隨退火溫度升高或時(shí)間延長(zhǎng),其E和H值通常降低,但Cu-Nb膜在晶化轉(zhuǎn)變后有所提高；電阻率則單調(diào)遞減。650℃-5 h退火后,Cu-74.91at.%Mo膜E和H值仍最高(分別為162.5和7.24 GPa), Cu-2.12at.%W膜電阻率仍最低(5.47 μΩ·cm)。Cu/W納米多層膜的Cu和W層均呈納米細(xì)晶結(jié)構(gòu),隨λ增加Cu{111}和W{110}織構(gòu)減弱或消失,W(110)晶面間距隨λ減小或η增加而減小�；旌线^(guò)渡層存在于Cu/W層間界面。厚厚增加時(shí),Cu層晶粒明顯增大且表面更光潔,W層晶粒尺寸和表面光潔度無(wú)明顯改變。調(diào)制參數(shù)λ和η顯著影響多層膜力學(xué)和電學(xué)性能�？傮w而言,當(dāng)λ或η增加時(shí),多層膜的屈服強(qiáng)度、彈性模量、硬度及電阻率趨于減小,裂紋萌生臨界應(yīng)變?chǔ)�。則隨λ減小或η增加而增加。調(diào)制參數(shù)改變引起層厚、層間界面數(shù)量及子層(尤其Cu層)微結(jié)構(gòu)的變化,使層內(nèi)和層間的位錯(cuò)運(yùn)動(dòng)和電子散射情況以及W層應(yīng)力強(qiáng)度因子改變,因此多層膜性能發(fā)生變化并呈規(guī)律性。
[Abstract]:Cu thin film has good conductivity, electromigration resistance and toughness, is widely used in microelectronics and micro mechanical field. But because of the poor adhesion strength, and hardness is not high, so the Cu film modified inevitable. Refractory metal and copper in nature are complementary, and refractory copper - gold a composite film often has special structure and excellent comprehensive performance. This paper chooses Cu-W, Cu-Mo and Cu-Nb three immiscible system as the research object, through the orthogonal test method, the use of magnetron sputtering, sputtering successfully with a combination of wide component Cu-W.Cu-Mo and Cu-Nb composite films were prepared, and the elemental target alternate preparation Cu/W nano multilayer film deposition. By analyzing the structure and properties of W, Mo test, and effects of Nb content on the structure and properties of Cu composite films and thermal stability, relationship between structure and properties of Cu/W nano multilayers and the modulation parameters. These studies Not only is the Cu to provide experimental basis and important support for application of molten metal films, and has guiding significance to design and research and development of novel functional thin film structure is proposed. The evaluation index to optimize the reasonable process, namely the target power density of PD was 8 W/cm2 P 2 Pa, sputtering pressure, target substrate distance Drs as for the process of 140 mm. unified film provides a guarantee effect, to discuss the rule of component content. The mosaic and superimposed composite target was designed to adjust the target area fraction that can effectively control the composition, simple process and good stability and repeatability, for copper based composite film preparation provides a new path. By using unbalanced magnetron sputtering technology, preparation of Cu composite films with metastable and amorphous structure, and the structure of W, Mo and Nb contents: (1) in W, Mo and Nb (with low content area (2.12 ~ 16.19) at.%W (2.19 ~ 15.12) at.%Mo and (from 1.16 to 23.4 3)at.%Nb),澶嶅悎钖勮啘鍛堢幇浜氱ǔ鍑嗘販婧舵，

本文編號(hào)：1764150