Exposure apparatus and focusing and leveling method thereof

Abstract

A projection exposure apparatus comprises a mask, a projection lens, a workpiece stage, a silicon wafer, a light source, a projection unit, a detection unit, a signal processing unit and a main controller; the projection lens is used to project the pattern of a mask to the upper surface of the silicon wafer on the workpiece stage; light emitted by the light source is incident on the silicon wafer via the projection unit, is reflected by the upper surface of the silicon wafer, and is received by the detection unit; and the signal processing unit processes the received light signal, obtains the pose information of the silicon wafer upper surface in a current measurement area, and sends the information to the main controller. Multiple measurement light spots are arranged on the silicon wafer of the projection exposure apparatus, multiple measurement points are arranged at the external of an exposure field, and multiple measurement light spots are arranged around the external of the exposure field.

Description

technical field [0001] The invention relates to the field of photolithography, in particular to a scanning exposure device and a focusing and leveling measurement method in a projection photolithography machine. Background technique [0002] A projection lithography machine is a device that projects the pattern on the mask onto the upper surface of the silicon wafer through the objective lens. In the projection exposure equipment, there must be an automatic focus control system to accurately bring the silicon wafer to the designated exposure position, and there are many different technical solutions for realizing this system. At present, non-contact photoelectric measurement technology is commonly used, among which the focusing technology of NIKON, CANON and other companies is the most representative. In these technologies, a set of optical systems is usually used to generate multiple light spots covering the entire exposure field for measurement. In the fringe field positi...

AI Technical Summary

Problems solved by technology

In these technologies, a set of optical systems is usually used to generate multiple light spots covering the entire exposure field for measurement. In the fringe field position, some measurement light spots may fall outside the silicon wafer and cause the light spots to be invalid. At this time, the current position needs to be calculated. The effectiveness of the spot array, using the measurement value of the still valid spot for focus and leveling control

The US patent US6381004 published by NIKON on April 30, 2002 provides a method to judge the effectiveness of each spot in the spot array one by one according to the current exposure field position, and then select an effective spot for measurement. This method can solve the problem of edge Field measurement, but there are defects such as large amount of calculation for spot validity judgment, complex spot selection and switching process, etc.

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