半導(dǎo)體銅布線阻擋層技術(shù)的研究
發(fā)布時(shí)間：2018-11-28 09:12
【摘要】：半導(dǎo)體工藝中特征尺寸的日漸減小,使得集成電路互連線的有效電流承載密度逐漸增大,電遷移問題越來越明顯,極大地影響到半導(dǎo)體器件的穩(wěn)定性,傳統(tǒng)的Al互連系統(tǒng)已經(jīng)難以滿足集成電路快速發(fā)展的性能需求,而Cu以其低電阻率、優(yōu)良的抗電遷移性能,逐漸取代Al,成為當(dāng)前應(yīng)用最廣泛的互連金屬。然而,Cu在Si襯底及其氧化物中非常容易發(fā)生擴(kuò)散,Cu金屬進(jìn)入Si器件中會(huì)成為深能級(jí)受主雜質(zhì),形成高電阻率的化合物,使得電路系統(tǒng)的漏電流增大,半導(dǎo)體器件的性能退化甚至失效;另外,Cu與Si、SiO2等材料接觸結(jié)合力較差,且在空氣中易發(fā)生氧化,致使互連線電阻率增大。所以,必須在Cu金屬與半導(dǎo)體襯底間加一層可以有效阻止兩者相互擴(kuò)散的阻擋層材料。研究電阻率低,可靠性高,性能優(yōu)良的擴(kuò)散阻擋層,并以阻擋層+銅互連金屬的膜系結(jié)構(gòu)作為互連系統(tǒng)是集成電路快速發(fā)展的重要方向,也是本課題主要的研究內(nèi)容。本文選用的擴(kuò)散阻擋層是以氮化鈥薄膜為基礎(chǔ)的復(fù)合膜層,輔以Ti單金屬層作為過渡層,增加互連系統(tǒng)各層之間的結(jié)合力,降低接觸電阻。Cu、Si分別作為互連金屬和半導(dǎo)體襯底,以磁控濺射作為主要工藝。深入地研究了膜系結(jié)構(gòu)、磁控濺射制備工藝、退火條件對(duì)互連系統(tǒng)性能的影響,并且研究了氮化鈦?zhàn)鳛樽钃鯇拥淖饔脵C(jī)制,其在高溫環(huán)境下的失效機(jī)理。制備了完整的Cu基半導(dǎo)體金屬化布線系統(tǒng),研究互連系統(tǒng)與Si直接接觸的結(jié)果,為Cu互連工藝的實(shí)際應(yīng)用提供可靠的實(shí)驗(yàn)數(shù)據(jù)。本課題的主要工作和成果如下:1,分析研究了Cu互連系統(tǒng)的擴(kuò)散機(jī)制與失效機(jī)制,研究了不同濺射工藝對(duì)阻擋效果的影響,設(shè)計(jì)并制備出Ti(15 nm)/TiN(25 nm)/Ti(15 nm)的復(fù)合膜系結(jié)構(gòu)作為阻擋層。測試結(jié)果證明,這種復(fù)合阻擋層的最高失效溫度可達(dá)900℃,穩(wěn)定性極好。2,以磁控濺射技術(shù)為主要工藝,設(shè)計(jì)并制備出結(jié)構(gòu)為TiN/Cu/Ti/TiN/Ti/Si的完整的Cu互連系統(tǒng),采用XRD,四探針等測試設(shè)備,分析表征該Cu互連系統(tǒng)的穩(wěn)定性、電阻率等性能。該Cu互連系統(tǒng)能夠在同一真空周期內(nèi)一次性完成制作,可操作性好,具有產(chǎn)業(yè)化應(yīng)用價(jià)值。3,分別在n型和p型Si上制備了 TiN(20 nm)/Ti(15 nm)/Si結(jié)構(gòu)的薄膜樣品,結(jié)合退火工藝,深入研究了退火對(duì)金屬Ti與n、p型Si之間接觸結(jié)果的影響,并測量阻擋層以及互連系統(tǒng)的方塊電阻。測試結(jié)果表明,Ti金屬層與p型Si,n型Si均可以形成歐姆接觸。
[Abstract]:With the decrease of characteristic size in semiconductor process, the effective current carrying density of integrated circuit interconnects increases gradually, and the problem of electromigration becomes more and more obvious, which greatly affects the stability of semiconductor devices. Traditional Al interconnection systems have been difficult to meet the rapid development of integrated circuit performance requirements, and Cu with its low resistivity, excellent resistance to electromigration, gradually replaced Al, as the most widely used interconnect metal. However, Cu diffuses easily in Si substrates and their oxides. Cu metal entering into Si devices becomes a deep level acceptor impurity, forming compounds with high resistivity, which increases leakage current of circuit system. The performance of semiconductor devices degenerates or even fails; In addition, the contact adhesion between Cu and Si,SiO2 is poor, and it is easy to be oxidized in air, which leads to the increase of interconnect resistivity. Therefore, a layer must be added between the Cu metal and the semiconductor substrate to effectively prevent the diffusion between the two materials. The study of diffusion barrier layer with low resistivity, high reliability and excellent performance is an important direction of the rapid development of integrated circuit, and it is also the main research content of this subject. The film system structure of copper interconnect metal in the barrier layer is the important direction of the rapid development of integrated circuit. The diffusion barrier layer selected in this paper is a composite film based on holmium nitride film, supplemented by Ti single metal layer as the transition layer, which increases the adhesion between the layers of the interconnection system and reduces the contact resistance. Cu,. Si is used as interconnect metal substrate and semiconductor substrate respectively, and magnetron sputtering is the main technology. The effects of film structure, magnetron sputtering technology and annealing conditions on the properties of interconnect system were studied. The mechanism of titanium nitride as a barrier layer and its failure mechanism at high temperature were also studied. A complete Cu based semiconductor metallized wiring system was prepared, and the results of direct contact between the interconnection system and Si were studied, which provided reliable experimental data for the practical application of Cu interconnection technology. The main work and achievements are as follows: 1. The diffusion mechanism and failure mechanism of Cu interconnection system are analyzed, and the influence of different sputtering processes on the barrier effect is studied. The composite membrane structure of Ti (15 nm) / TiN (25 nm) / Ti (15 nm) was designed and fabricated as the barrier layer. The test results show that the maximum failure temperature of the composite barrier layer can reach 900 鈩，
本文編號(hào)：2362426
[Abstract]:With the decrease of characteristic size in semiconductor process, the effective current carrying density of integrated circuit interconnects increases gradually, and the problem of electromigration becomes more and more obvious, which greatly affects the stability of semiconductor devices. Traditional Al interconnection systems have been difficult to meet the rapid development of integrated circuit performance requirements, and Cu with its low resistivity, excellent resistance to electromigration, gradually replaced Al, as the most widely used interconnect metal. However, Cu diffuses easily in Si substrates and their oxides. Cu metal entering into Si devices becomes a deep level acceptor impurity, forming compounds with high resistivity, which increases leakage current of circuit system. The performance of semiconductor devices degenerates or even fails; In addition, the contact adhesion between Cu and Si,SiO2 is poor, and it is easy to be oxidized in air, which leads to the increase of interconnect resistivity. Therefore, a layer must be added between the Cu metal and the semiconductor substrate to effectively prevent the diffusion between the two materials. The study of diffusion barrier layer with low resistivity, high reliability and excellent performance is an important direction of the rapid development of integrated circuit, and it is also the main research content of this subject. The film system structure of copper interconnect metal in the barrier layer is the important direction of the rapid development of integrated circuit. The diffusion barrier layer selected in this paper is a composite film based on holmium nitride film, supplemented by Ti single metal layer as the transition layer, which increases the adhesion between the layers of the interconnection system and reduces the contact resistance. Cu,. Si is used as interconnect metal substrate and semiconductor substrate respectively, and magnetron sputtering is the main technology. The effects of film structure, magnetron sputtering technology and annealing conditions on the properties of interconnect system were studied. The mechanism of titanium nitride as a barrier layer and its failure mechanism at high temperature were also studied. A complete Cu based semiconductor metallized wiring system was prepared, and the results of direct contact between the interconnection system and Si were studied, which provided reliable experimental data for the practical application of Cu interconnection technology. The main work and achievements are as follows: 1. The diffusion mechanism and failure mechanism of Cu interconnection system are analyzed, and the influence of different sputtering processes on the barrier effect is studied. The composite membrane structure of Ti (15 nm) / TiN (25 nm) / Ti (15 nm) was designed and fabricated as the barrier layer. The test results show that the maximum failure temperature of the composite barrier layer can reach 900 鈩，
本文編號(hào)：2362426
本文鏈接：http://sikaile.net/kejilunwen/dianzigongchenglunwen/2362426.html
最近更新
教材專著
