Method for measuring Cube-Prism non-orthogonality angle and scale factor correct value

Abstract

A method for measuring corrected values of non-rothogonality angles and scaling factors of a square mirror comprises the following steps: placing and exposing a marking image (A) on a mask onto a gummed blank silicon wafer via a photoetching system according to a designated graph, and taking off the wafer when exposure is completed; putting up the wafer after rotating the silicon wafer by a certain angle, placing and exposing a marking image (B) on the mask onto the silicon wafer according to the same graph, wherein compared to the first layer, the exposure marking position is deviant; developing again when the exposure is completed; putting up the wafer again without rotating the silicon wafer, and reading all the marking positions after aligning the marks on the silicon wafer via an off-axis alignment system of a photographic machine; and calculating the non-rothogonality angles and the scaling factors of a coordinate system of a working piece table according to the measured marking positions. The measurement method is an absolute measurement method, and can be applied in different photoetching systems.

Description

technical field

[0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for measuring the non-orthogonal angle of a square mirror and the correction value of a scaling factor. Background technique

[0002] Because there is a certain mechanical deviation when the X square mirror and Y square mirror of the workpiece table are installed, the X square mirror and Y square mirror in the actual lithography machine system are not absolutely vertical, which leads to the establishment of the workpiece table coordinate system (coordinate system y axis Parallel to the X square mirror) there is non-orthogonality. When the workpiece table scans and exposes along the X and Y axes, the resulting graphics will appear distorted. In addition, due to the mismatch between the X and Y direction interferometers of the workpiece table, the scaling ratio between the X-axis and Y-axis coordinates will be different.

[0003] The commonly used method to det...

Images