Method for detecting offset of focus of lithography machine

Abstract

The invention relates to the field of semiconductor manufacturing, in particular to a method for detecting offset of focus of a lithography machine. According to the method for detecting the offset of the focus of the lithography machine, the offset of the focus of the lithography machine is monitored by depending on monitoring the similarity level of an actual measurement graph and a reference graph, the change condition of the focus of the lithography machine can be immediately and effectively judged through measuring massively-produced wafers, and measurement interference can be avoided, thus judgment errors caused by the measurement errors are avoided.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits and the manufacture thereof, in particular to a method for detecting focal length offset of a photolithography machine. Background technique [0002] As the integration level of integrated circuits continues to increase, semiconductor technology continues to develop rapidly. With the continuous improvement of semiconductor performance requirements, the size of integrated circuit chips is getting smaller and smaller, and the photolithography process has gradually become the core process in chip manufacturing. Usually, in a complete chip manufacturing process, multiple photolithography processes are required. For example, in a complete 45nm process chip manufacturing process, about 40 to 60 photolithography processes are required depending on the performance requirements; As the size shrinks, the pattern of lithography will also shrink accordingly, and the thickness of photoresist a...

AI Technical Summary

Problems solved by technology

[0003] In the lithography process, if the focal length of the lithography machine cannot be detected in time, it will bring huge losses to the production; the existing technology mainly uses the method of measuring key dimensions or measuring the overlay accuracy for monitoring, but A special exposure of a wafer is required to monitor the condition of the machine, and at the same time, the measurement of key dimensions has relatively high requirements on the measurement position. When the measurement position changes, it will bring great interference to the final result.

Images