SF_6/O_2等离子体刻蚀a-C:F薄膜的研究  

Study on Etching Techniques of a-C:F Films in SF_6/O_2 Plasma

作　　者：吴振宇[1] 杨银堂[1] 汪家友[1] 柴常春[1] 

机构地区：[1]西安电子科技大学微电子研究所宽禁带半导体材料与器件教育部重点实验室,西安710071

出　　处：《微细加工技术》2007年第1期36-40,共5页Microfabrication Technology

基　　金：电子元器件可靠性物理及其应用技术国家级重点实验室项目资助课题(51433020205DZ01);西安-应用材料创新基金资助项目(XA-AM-200501)

摘　　要：以SF6/O2为刻蚀气体,采用电子回旋共振等离子体反应离子刻蚀(ECR-RIE)方法进行了氟化非晶碳(a-C∶F)低介电常数薄膜的等离子体刻蚀技术研究,结果表明,a-C∶F薄膜的刻蚀速率取决于薄膜中C—CFx与CFx两类基团刻蚀过程,富C—CFx结构的a-C∶F薄膜刻蚀速率在O2含量约20%时达到最大,而富CFx结构的a-C∶F薄膜刻蚀速率随O2的增大而减小。AFM分析表明,SF6气体刻蚀a-C∶F薄膜可以有效消除薄膜表面的团聚结构。XPS能谱分析表明,SF6气体刻蚀a-C∶F薄膜样品化学组分未发生变化,而O2气体刻蚀后在样品表面形成富C的a-C∶F层。该研究结果为a-C∶F应用于超大规模集成电路层间介质工艺奠定了必要的实验基础。Plasma etching techniques of low-dielectric-constant fluorinated amorphous carbon (a-C:F) films in SF6/O2 mixtures using electron cyclone resonance reactive ion etching (ECR-RIE) method were studied. Experimental results show that the etching rate of a-C:F films is dependent on the etching process of CFx and C-CFx species in the films. The maximum etching rate of the (C-CFx)-rich a-C:F films is reached when the oxygen gas flow ratio is approximately 20%. The etching rate of (CFx)-rich a-C:F films decreases with increasing oxygen gas flow ratio. AFM analysis shows that fluorine plasma can effectively reduce the aggregation of fluorocarbon particles at the film surface. X-ray photoelectron spectra indicate that no remarkable change in chemical structures after SF6 plasma etching and the formation of carbon-rich layer after O2 plasma etch. This technique and experimental results may serve applications of a-C:F films as ULSI inter-layer dielectrics.

关 键 词：a-C∶F 等离子体刻蚀 表面形貌 XPS 

分 类 号：O484.8[理学—固体物理]