Liquid supply and recovery seal controller in immersion type photoetching system

Abstract

The invention discloses a liquid supply and recovery sealed control device in an immersed photoetching system, arranging a liquid supply and recovery sealed control device between projection lens and to-be-exposed silicon wafer in the immersed photoetching system. And the control device comprises immersed unit outer pipeline connector, immersed unit cavity and immersed unit operating surface; and it adopts double gas curtain seal and double multiporous medium recovery mode, and the seal gas injection and gas-liquid mixed recovery pipelines both have buffering and pressure equalizing structures, and gas flow curtain stably flowing and having uniform pressure difference is obtained on the boundary of in-gap flow field, stopping liquid leakage in the stepping and scan travel; besides, in the liquid recovery part, the increased effective operating surface reduces the staying liquid on the surface of the silicon wafer; and it has stronger ability of resisting supply pulsation of gas source; the seal gas curtain has small thickness, the input power of the gas source is low and high-efficiency; and the total back pressure of the silicon wafer is reduced.

Description

technical field [0001] The invention relates to a sealing control device for liquid supply and recovery in an immersion lithography (Immersion Lithography) system, in particular to a liquid in the gap between the near field end element of the projection lens group (Lens) and the silicon wafer (Wafer). It is a liquid transmission and sealing control device that transports liquid and ensures that the liquid does not leak. Background technique [0002] Modern lithography equipment is based on optical lithography, which uses an optical system to accurately project and expose the pattern on the mask onto the silicon wafer coated with photoresist. It includes an ultraviolet light source, an optical system, a projection mask composed of chip patterns, an alignment system and a silicon wafer covered with photosensitive photoresist. The immersion lithography system fills the gap between the projection lens and the silicon wafer with some kind of liquid, and increases the numerical a...

AI Technical Summary

Problems solved by technology

[0004] (1) The phenomenon of uneven flow and pressure concentration at the gas sealing boundary

Uneven air flow is not conducive to liquid sealing on the one hand, and causes leakage during stepping and scanning. On the other hand, it may cause cracking of the gap flow liquid film, causing air bubbles to enter the exposure field between the projection lens and the silicon wafer, thereby affecting imaging. quality

[0005] (2) The air sealing effect is not good, and too much liquid stays on the working surface

The effective working area of ​​the liquid recovery part is small, and the liquid cannot be recovered in time during the movement stroke of stepping and scanning, resulting in a large amount of retention

[0006] (3) The gas demand for airtight work is too large

Excessive gas demand has high requirements on the supply of the back-end source, which is not suitable to ensure continuous and pulsation-free. At the same time, under high-speed motion, it is not conducive to the uniformity of the static pressure on the surface of the silicon wafer and the reduction of the back pressure on the surface of the silicon wafer, which affects the imaging quality.

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