Focusing and leveling detection apparatus

Abstract

Disclosed is a focusing and leveling detection apparatus for adjusting light sources. Lights emitted from a light source in the apparatus are divided into two beams by a spectroscope: one beam undergoes light intensity detection by a light intensity detector; and the other beam is incident on materials of a silicon chip and the like through a projector unit and finally enters a signal processing unit after being reflected by the silicon chip, wherein the signal processing unit is used for photoelectric conversion and signal processing. A main controller is used to control a light source controller or the signal processing unit according to the light source's current optical intensity signal situation detected by the light intensity detector.

Description

technical field [0001] The invention relates to the field of lithography, in particular to a focusing and leveling detection device applied to a lithography machine. Background technique [0002] A projection lithography machine is a device that projects the pattern on the mask onto the surface of a silicon wafer through a projection objective lens. In order to make the wafer surface at the specified exposure position, there must be an automatic focusing and leveling system for precise control. At present, ASML, NIKON, and CANON's automatic focusing and leveling technologies are the most representative. The automatic focusing and leveling system is generally composed of light source, diaphragm, projection branch, detection branch, signal processing unit and other parts to obtain the height and tilt information of the silicon wafer surface in the exposure field. Usually, the light source used in the design of the automatic focusing and leveling system is set to run at the o...

AI Technical Summary

Problems solved by technology

Usually, the light source used in the design of the automatic focusing and leveling system is set to run at the optimal power and emit approximately constant light intensity, but in fact the light source is aging, and its overall light intensity shows a decreasing trend, which makes the automatic focusing After the incident light projected by the projection branch of the leveling system onto the surface of the silicon wafer is reflected, its light intensity attenuation becomes larger, and the light intensity signal detected by the detection branch becomes weaker, which affects the detection accuracy of the automatic focusing and leveling system. The aging problem of the light source in the focusing and leveling system is improved

[0003] The publication date of SMEE is July 24, 2009. Chinese patent application 200910055388.4 provides a method for adjusting the aging light source of the automatic focusing and leveling system by using a reference plate. The process of this method is relatively simple, but there are also needs Use the reference board to perform regular maintenance on the light source, which increases the complexity of customer use.

[0004] The premise of the technologies such as multi-point detection and modulation of the detection slit imaging image adopted by the automatic focusing and leveling system of the lithography machine is that the light intensity of the light source used in the design is constant, but in fact the light source is constantly aging, which makes the automatic adjustment The light intensity signal detected by the detection branch of the focal adjustment bisection system becomes weaker, which reduces the signal-to-noise ratio and affects the detection accuracy of the sub-system

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