A reflective multi-off-axis mirror vertical measuring device

Abstract

The invention discloses a vertical measuring device using reflective multi-off-axis mirrors, which is characterized in that it comprises: light emitted by a light source passes through an illumination optical system to form a measuring beam, and the measuring beam passes through a measuring optical system, The measurement optical system is composed of a projection branch, an object to be measured, and a detection branch; the measurement beam passes through the projection pattern forming unit of the projection branch in sequence, and the off-axis aspheric surface with refractive power of the projection branch After the mirror group reaches the surface of the object to be measured; the reflected light beam of the measuring beam on the surface of the object to be measured passes through the off-axis aspheric mirror group with refractive power of the detection branch and the detection branch in sequence The projected pattern receiving unit is then detected by a detector to obtain vertical information on the surface of the object to be measured.

Description

technical field [0001] The invention relates to the field of integrated circuit equipment manufacturing, in particular to a reflective multi-off-axis mirror vertical measuring device. Background technique [0002] As the operating wavelength of the projection lithography machine continues to decrease and the numerical aperture continues to increase, the measurement accuracy requirements for the vertical measurement device of the silicon wafer are becoming increasingly stringent. One of the important factors affecting the measurement accuracy of the silicon wafer vertical measurement device is the interlayer interference effect generated after the measuring beam passes through the multi-layer complex patterns on the silicon wafer. To solve this problem, visible to near-infrared wide-spectrum light sources are widely used to provide illumination for silicon wafer vertical measurement devices to homogenize the interlayer interference effect of different wavelengths of illuminat...

AI Technical Summary

Problems solved by technology

[0003] However, most of the optical systems of silicon wafer surface vertical measurement devices are transmissive. The optical system structures of vertical measurement devices with different working wavelengths are very different, and the materials of the lenses are also very different.

If broad-spectrum illumination from ultraviolet to short-wavelength visible light is used, such as 50-500nm, it will bring many challenges to the optical system design of the silicon wafer vertical measurement device, and severe chromatic aberration is one of them

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