Lithography tool is the most important equipment for microelectronics manufacturing industry. Lithography tool development is towards to improving resolution and uniformity, because of the miniaturization of modern electronics manufacturing. Illumination system in lithography plays a significant role in improving resolution and the uniformity. 193 nm ArF laser source is widely used in modern lithography design. The output beam size of the ArF source can’t satisfy the requirements of the following components, so the first task of illumination system is to design beam expander. Three different beam expanders for 193 nm ArF laser source are designed in this paper. The uniformity and threedimensional distribution of each beam expander’s exit beam are simulated and compared in the software of TracePro. Characteristics of the different beam expanding systems are analyzed. Afterwards the paper compares and summarizes the advantages and disadvantages of three expanding systems. At last the article gives some suggestions on choosing different beam expanding systems.
Lithography tool is a necessary part for LSI and VLSI. The illumination system design is an important part in the
lithography optical system design. Off-axis illumination technology is an effective way to reducing resolution of
lithography. The paper introduction the basic components of lithography tool, the principle of off-axis illumination
reducing the resolution of lithography and focus on the two implementations of OAI technology, finally point out
advantages and disadvantage of the two implementations.
Illumination system is one of the most important parts of the micro-lithography object lens. Its performance can greatly
affect the lithography machine's etching graphic quality. In this paper, we discuss a DUV micro-lithography illumination
system which can achieve high uniformity and a large illuminated area on the mask. According to the large numerical
aperture requirement, a refractive illumination system is designed and optimized with software ZEMAX. The system
also meets the requirement of large illumination area on the mask, and no aspherical lens is used. Characters of different
illumination structures and modes are introduced here. Then by using the software of TracePro, illumination systems
with different kinds of aperture are modeling and illuminaces are analyzed. We research effect of illuminace on the mask
which bring by different kinds of aperture. Also in this paper, we make a study of relationship between different
illumination mode and different kinds of graphics. Finally, we compare the results and give suggestion about how to
choose illumination mode. That is meaningful for choosing different aperture in illumination system of microlithography.
In semiconductor industry, exposure tools have been improved in resolution. 193 nm lithography is one of the promising
technologies for the fabrication of critical dimension from 100 to 32 nm. The optical performance of projection lens is
the key factor to realize high resolution pattern. This paper presents the design process of a refractive lithography
projection lens utilizing aspheric surfaces. The objective, as built, has a numerical aperture of 0.75, a maximum
astigmatism of 30 nm and a total focal plane deviation of 45 nm. With the assistant of resolution enhancement
technology, image resolution can reach 90 nm. Aspheric surfaces can be used to correct aberrations, to make optical
systems more compact, and in some cases to reduce cost. Systems with and without aspheric surfaces are compared in
the paper so as to find their differences in aberrations and configuration. We found that aspheric surfaces dramatically
decrease the RMS wavefront error from 3 nm to 1 nm. Differ in position of aspheres can be used to correct aperture
dependent aberrations (spherical aberration), and to correct field dependent aberrations (distortion and field curvature).
We explored the connection between position of aspheres and different aberrations by APS (Aspheric surfaces selecting
factor). Aspheric surfaces also make the system more applicable by reducing the system volume and leaving proper edge
thickness for mechanical structure.