Focusing and leveling method used for projection photoetching machine

Abstract

The invention discloses a focusing and leveling method used for a projection photoetching machine. The method is characterized in that the method comprises the following steps: 1, globally focusing and leveling a detected substrate to make each of measuring fields on the substrate is in the measuring range of a focusing and leveling sensor; 2, carrying out first-time scanning along a stepping direction to obtain first focusing and leveling data of all the measuring fields and all measuring points; 3, carrying out second-time scanning after the detected substrate is rotated according to a certain angle to obtain second focusing and leveling data of all the measuring fields and all the measuring points; and 4, summing and averaging the data obtained in step 2 and the data obtained in step 3 to obtain the Z-axial offset distances of all the measuring points, and calculating according to the Z-axial offset distances to obtain the Rx, Ry and Z values of all the measuring fields in a present position to the zero plane of the focusing and leveling sensor.

Description

[0001] technical field [0002] The invention belongs to the field of integrated circuit equipment manufacturing, in particular to a focusing and leveling method for a projection photolithography machine. Background technique [0003] The projection lithography machine can improve the lithographic resolution by reducing the exposure wavelength and increasing the numerical aperture of the projection objective lens, but at the same time it will lead to a significant decrease in the available focal depth, making the silicon wafer surface more prone to defocus. In order to solve the defocus problem caused by the reduction of focal depth, high-end projection lithography machines use focusing and leveling technology to control the height and tilt of the silicon wafer surface in real time. Focusing and leveling technology includes focusing and leveling measurement technology on the silicon wafer surface and real-time control technology on the position of the silicon wafer sur...

AI Technical Summary

Problems solved by technology

[0004] In order to avoid contamination and damage to the graphics on the surface of the silicon wafer, non-contact measurement technology must be used for the silicon wafer focusing and leveling measurement. Commonly used silicon wafer focusing and leveling sensor technology solutions include: (1) air pressure position measurement technology, characteristics It directly measures the physical surface of the silicon wafer, and is not affected by the photoresist and the surface material of the silicon wafer; the air pressure is greatly affected by the environment, and the accuracy is not high; the sensor is close to the silicon wafer, and the exposure field cannot be directly measured; (2) Capacitance Measurement technology is characterized by relatively simple implementation; it is greatly affected by the characteristics of the silicon wafer to be tested; the sensor is close to the silicon wafer and cannot directly measure the exposure field; (3) optical measurement technology is characterized by the ability to directly measure the exposure field, which is the current mainstream The advanced focusing and leveling technology scheme has high detection accuracy, and the optical machine and control structure are complex, but the detection accuracy is greatly affected by the reflectivity of the silicon wafer surface

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