VLSI曝光成像效果的技术研究

【作者】 马建霞；

【导师】 贾宇明； 张波；

【作者基本信息】 电子科技大学 ， 材料学， 2005， 硕士

【摘要】 光刻技术是半导体产业发展的关键驱动力之一。摩尔定律表明芯片上集成元器件的数目每18 个月增加1 倍;瑞利定则指引着光刻技术的发展。要保持该产业持续发展30 余年,有光刻、增加硅片尺寸和设计三个主要技术构成。集成度的提高约有一半来自于光刻技术的提高。光刻技术主要分为曝光和刻蚀两个阶段。曝光成像的完整性和精确性是实现良好的电路复制的基础。描述成像性能的主要特征参数包括:分辨率、焦深、CD 控制、前后图层间的套准精度、成像均一性。其中,分辨率和焦深是两个相互制约的特征参数,分辨率是关键尺寸能否达到的前提条件。大多光刻技术研究的重点在于分辨率的提高。分辨率的提高成为主要驱动力,CD 控制和套刻容差进一步驱动着它的发展。CD 控制的要求(即均匀性)被设定为±10%的范围,套准精度被定义为CD 的1/3。高分辨率印制方法能够解决小于30nm 的光刻,但是光刻尺寸的最终极限更可能由CD 控制要求和经济角度决定而不是纯粹的分辨率能力。本课题主要针对现阶段紫外光投影光刻机的成像效果进行分析,理论依据为透镜成像原理和光刻胶线宽变化机理。本文首先引入瑞利定则,对光刻技术的现状和发展趋势进行论述,重点讨论了先进的光学光刻技术;围绕分辨率和焦深两个参数展开讨论;将影响光刻效果的因素与光刻胶线宽变化预测模型相结合,设定单因素试验从光刻机的光源系统、调焦系统、掩膜版和棱镜的畸变、光刻胶之间的成像差异、晶片本身及工艺中不同膜层的应力的变化等角度进行论证分析。整个课题的研究以工程应用为目的,涉及到光学、微电子工艺、化学及高分子材料等交叉学科,通过基础理论去指导和把握实验方向,很大程度上改善了光刻曝光的成像效果,最终提高在线产品的成品率。更多还原

【Abstract】 Lithography technique has been one of the key drivers for the semiconductor industry. Moore’s law states that the number of devices on a chip doubles every 18 months. There are three main basics of the technology improvements that have kept the industry on this pace for more than 30 years. They are lithography, increased wafer size, and design. Roughly half of the density improvements have been derived from improvements in lithography. Lithography techniques mostly comprise exposure and etch phases. Exposure imaging’s integrality and exactness are the basis of circuit reproduce. Character parameters include focus, resolution, critical dimension control, overlay and exposure uniformity, which can be used to depict imaging performance. Resolution and focus are both parameters, which restrict each other. The realization of critical dimension lies on resolution. Many lithography studies pay more attention to the advance of resolution, which is the primary driver. The controls of CD and overlay tolerance accelerate the advance of resolution at some certain extent. CD variation was set in a ±10 percent range , overlay tolerance is 1/3 of CD. High-resolution printed circuit can satisfy the demand of 30nm lithography. However, the limit of lithography is likely to be decided by CD control and economic. The project mainly analyzed the imaging effect of UV projection exposure, which base on optical image and CD variation mechanism. First, the aim of introducing Raleigh rule is to discuss actuality and trends of lithography technique, especially in advanced optical lithography aspects. Second, talking over resolution and focus is the center of thesis. Third, combining photo resist’s line width variation forecast model with imaging factor to design experiment from all of angle such as lamp-house system, focus system, the aberration of mask and lens, photo resist, wafer flatness and thin film difference etc. The thesis aims at engineer application, which involved optics, microelectronics process, chemistry, polymer material science etc. We can grasp and supervise the way of experiment by basic theory. To very large degree, the experiments improve the effect of imaging and production performance.更多还原