摘要
集成电路(IC)制造是电子信息产业的核心,是推动国民经济和社会信息化发展最主要的高新技术之一。IC产业的加速发展为IC装备带来了广阔的发展空间。IC制造涉及很多工艺,每种工艺前都需要进行晶圆传输、定位和姿态调整。用来完成晶圆加工前这些操作的IC制造装备被称为晶圆处理系统。晶圆预对准系统是晶圆处理系统重要组成部分之一,其重复定位精度要求高,预对准时间对IC的生产效率有影响,因此研制具有小型化、集成化、高精度、高效率的晶圆预对准系统具有重要的实际和应用价值。
本课题来源于国家高技术研究发展计划(863计划)课题:掩膜管理和晶圆处理系统的研究。主要研究内容是研制用于12英寸晶圆的小型化预对准系统。
通过预对准方案的精度分析与比较,确定系统的总体方案。根据系统的功能与组成,分别对精密定位系统、检测系统、真空吸附系统、机械结构进行设计,建立了晶圆预对准系统的硬件结构。
根据预对准系统控制任务确定了预对准控制器总体结构,分别对各控制功能模块进行硬件和软件设计,完成了预对准系统控制器的研制。
对晶圆预对准算法从晶圆圆心定位算法和晶圆缺口定位算法两方面进行了研究。对基于线性化最小二乘圆拟合算法的圆心定位算法进行了精度分析和效率改进。针对线性化最小二乘圆拟合算法用于缺口拟合的不足,提出一种基于Levenberg-Marquardt算法的缺口拟合算法。另外,对缺口定位部分的其他关键参数计算进行了叙述,完成了预对准控制程序的编制。
通过系统误差分析,验证了系统在设计上满足晶圆预对准的重复定位精度要求。利用光学显微镜测定了系统重复定位精度,实验结果表明系统重复定位精度和预对准时间均达到了技术指标要求。
As the hard-core of electronic information industry, integrated circuit (IC) manufacturing is one of the most important technologies which promote national economy and social informatization developing. With the accelerating development of integrated circuit industry, it's an urgent need for more IC equipments. The IC manufacturing involves many processes, and wafer is needed to be transferred, located and orientated before each of processes. Wafer processing system is one of IC equipments, which completes above three operations. Wafer pre-alignment system is an important subsystem of wafer processing system. The repetitive positioning accuracy of wafer pre-alignment system is required critically and the consuming time affects the efficiency of the entire manufacturing. Therefore, it is meaningful to design a wafer pre-alignment system with the characteristic such as miniaturization, integration, high precision and high efficiency.
This work is supported by the High Technology Research and Development Program of China. The main content of the research is to design a small-scaled wafer pre-aligner for 12-inch wafer.
System scheme is selected after the analyzing and comparison of the pre-alignment scheme accuracy. Positioning system, detecting system, vacuum suction system and mechanical structure are designed according to the function of the system and complete the establishment of the small-scaled wafer pre-aligner.
The structure frame of the controller is constructed after selecting center processing unit. The hardware and software of each sub-function module are designed respectively, and complete the design of the wafer pre-alignment controller.
Wafer centering algorithm and notch orientating algorithm are studied. The efficiency of wafer centering algorithm is improved and a new notch orientating algorithm is proposed to fit the notch, which is based on Levenberg-Marquardt algorithm and validated to improve the accuracy effectively by experiment. Additionally, the computations of some key parameters of notch orientating are presented, and accomplish the compiling of the control program.
The precision analysis of the wafer pre-alignment system is done, which confirmed that the request precision of the system is satisfied by the design. The repetitive positioning accuracy is measured by optical microscope. The experiment results show that the repeatability of the orientation and the average time of the pre-alignment satisfy the technical specifications.
引文
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