【作者】 杨志永；

【导师】 孙秀冬；

【作者基本信息】 哈尔滨工业大学 ， 光学， 2009， 硕士

【摘要】 随着制造加工技术的进步,微电子工艺不断向前发展。刻蚀工艺不仅作为微电子工艺中的关键技术一直受到人们的关注,而且在新兴的微机电系统,光电集成系统等微细加工中也将得到重要应用。等离子体刻蚀是一种重要的微加工方法,在硅器件的微细加工中己经得到广泛应用。但是其机理至今还不是很明确,刻蚀工艺的研究主要还是依赖经验和反复试探。利用计算机对这一过程进行模拟可以节省许多人力物力,并可作为做实验的参考。本文首次提出用扩散限制腐蚀模型(Diffusion Limited Erosion)对等离子体蚀刻过程进行模拟。首先讨论了刻蚀工艺的基本原理,分析了等离子体刻蚀过程中的各个参量与模型中参数对应关系。然后对扩散限制腐蚀模型进行改进,并且编程实现该模型的算法。在单周期掩模条件对模型进行模拟计算。研究鞘区电压对刻蚀剖面的影响。调制几率对应等离子体刻蚀中鞘区电压。当鞘区电压升高时,模型中的调制几率增大。研究发现当调制几率为0.25时刻蚀为各向同性,对应刻蚀过程中的纯化学刻蚀过程。当调制几率为1时,刻蚀为完全各向异性,横向刻蚀速率为零。模型对应离子轰击过程。当调制几率逐渐增加时,刻蚀速率的各向异性性增强,钻蚀效应减弱。但是调制几率增加的同时也导致刻蚀槽表面的粗糙度增加。所以在等离子体刻蚀过程中,鞘区电压是影响刻蚀质量的重要参数。更改掩模结构,采用周期性掩模。模拟计算结果表明当调制几率较小时,由于钻蚀,形成锥状结构。当刻蚀继续进行时,锥状结构被抹平。增大调制几率到0.6时可以得到高深宽比结构的刻蚀剖面。模拟过程中出现了深宽比依赖效应,即当刻蚀槽深度远大于宽度时,刻蚀深度降低。模拟结果与文献中的等离子刻蚀硅实验结果进行比较。说明本模型是有效的。扩散限制刻蚀模型是一种新的等离子体刻蚀模拟方法,期望本论文的工作对等离子体刻蚀工艺改善提供帮助。更多还原

【Abstract】 With the development of manufacture technology, microelectronic process is going forward. As an important step of microelectronic process, etching technology has gained much attention. It will play an important role in micro fabrication such as new-made microelectronics mechanism and photo electronics integration system. Plasma etching has been widely used in the etching process of Si devices. Plasma etching is an important method in micro manufacture, but the mechanism of this process is not sure today. Researchers always rely on experiment and experience to study etching technology. Computer simulations can save a lot of time and money, and can also be predictive in its applications to the technology of device manufacture. A diffusion limited erosion (DLE) model is suggested to study plasma etching.First the mechanism of plasma etching process was introduced, common modes and simulation method was introduced too. Then the DLE model was improved and the simulation program was finished.The influence of sheath electric filed on plasma etching process was investigated with simple mask. In our model, hopping probability ( ) represent the magnitude of sheath electric filed. Simulations were performed with various . When , the etching process is totally isotropic. When , this model changed to ballistic etching. Etching process became more anisotropic and undercut decreased as increased, but the roughness of grooves increased. So the magnitude of sheath electric filed is an important parameter of plasma etching.Simulations were performed with periodic mask. A serials of taper like structure were appeared when the vale of is small, as the result of strong undercut effect. That structure was eliminated as etching process continues. High aspect ratio grooves were showed when PePe = 0.6. Aspect Ratio Dependent Etching was observed in simulation results. Simulation results were almost same with experimental results in other papers.DLE model is a new method in plasma etching simulations. We hope though further development this model can be used to guide etching industry.更多还原