对半色调式PSM的应用中旁瓣效应的研究.pdfVIP

摘 要 近二十年来，集成电路技术迅猛发展，集成度的不断提高一直遵从摩尔定律： 动态随机存储器(DRAM)的集成度每十八个月翻一番。随着芯片特征尺寸的微 缩，芯片图案集成度的增高，光刻作为整个半导体制程中的非常重要的一个环节， 也面临着越来越多的挑战。解析度增强技术的研发和应用减小了光刻所能提供的 特征图形尺寸，推动着半导体行业不断的前行。 本文详细介绍了提高曝光分辨率的离轴照明技术；提高图形对比度的相位移 掩模技术；使显影图形更接近电路设计，提高电路可靠性的光学临近效应修正技 术；消除基底反射的抗反射层涂布技术。 在半色调式 PSM 的应用中，由于半透明材料作为遮光膜，曝光时光束可以 局部穿透，在改善成像质量的同时，不可避免的会产生漏光的问题,造成旁瓣效 应。随着集成电路线宽进入亚微米尺寸以后，曝光光源相应的由 I-line 发展到 KrF。但是因为 KrF 比较弱的照明强度，光刻胶也在朝着较高感光灵敏度和对比 度的方向变化着，在成像质量和成像速度大幅提高的同时，极易因旁瓣的光强达 到光刻胶的临界能量从在硅片上成像，导致芯片良率损失。 本文以芯片生产中因旁瓣成像导致良率损失的产品为例，通过扫描电子显微 镜对硅片成像进行详细地的观察分析，深入地研究了光掩模图形制作尺寸和曝光 数值孔径对曝光能量的影响，得出了硅片上旁瓣成像的有效解决方案，对提高产 品的良率有重要意义。 关键词：离轴照明 相位移掩模 光学临近效应 旁瓣效应 ABSTRACT In the recent twenty years, IC technology made a huge progress. The integration keeps on increasing following Moores law: the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years (or 18 months). With the critical dimension turns smaller and smaller, and the integration turns higher and higher, lithography meets more and more challenge. The development and application of resolution enhance technology increased lithography process capability and drive IC industry moving. This paper also introduces the technology such as the OAI which can improve resolution, PSM which can enhance the contrast, OPC that can improve IC reliability, BARC resist which is used to reduce the reflection. The half tone phase shift mask(PSM) use the semitransparent material to block exposure light. The unwanted light induce side lobe effect while PSM improving the image quality. With the development of IC industry, the exposure light source do relative evolution from I-Line to KrF.Meanwhile,KrFs lower illumination intensity drives photoresist to higher sensitivity and contrast.