聚焦对投影光刻系统（如步进机）的影响是了解及控制光刻工艺的关键因素。随着特征尺寸的减小，它对聚焦误差的灵敏度迅速升高。因此，许多人认为聚焦灵敏度是光学光刻进入更小特征尺寸的主要障碍。本文将对焦深的定义作以定量的分析 The impact of focusing on projection lithography systems such as steppers is a key factor in understanding and controlling the lithography process. As the feature size decreases, its sensitivity to focus error increases rapidly. Therefore, many consider the focus sensitivity to be a major obstacle to optical lithography entering smaller feature sizes. This article will focus on the definition of a quantitative analysis