Immersion lithography method and system

Abstract

The present invention provides a method of performing immersion photolithography on a semiconductor substrate and a processing system thereof. The method of immersion photolithography includes: providing a photoresist layer on a semiconductor substrate, and exposing the photoresist layer using an immersion photolithography exposure system. the photoresist layer. The immersion lithography exposure system uses liquid during exposure and removes some but not all of the liquid after exposure; after exposure, a process step is used to remove residual liquid on the photoresist layer; after treatment, a post-exposure bake is performed and developing steps.

Description

[0001] This application is a divisional application with an application date of June 29, 2006, an application number of 200610100019.9, and an invention title of "immersion photolithography method and its processing system". technical field [0002] The invention relates to a manufacturing method of a semiconductor device, in particular to a method and system for removing photoresist residues on a semiconductor substrate. Background technique [0003] Photolithography is the technique of projecting a pattern on a mask onto a substrate such as a semiconductor wafer. In the field of semiconductor lithography technology, it is necessary to minimize the feature size of the pattern on the semiconductor wafer under the resolution limit or critical dimension, and the current critical dimension has reached below 65nm. [0004] Semiconductor photolithography generally includes coating photoresist on the top surface of a semiconductor wafer (such as a thin layer stack structure), expo...

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Problems solved by technology

[0006] In the immersion exposure step, deionized water or other suitable immersion exposure liquid can be used between the wafer and the lens. Although the exposure time is very short, the liquid is sensitive to light. Contact of layers (such as photoresist) can cause problems, such as small droplets left after processing, and / or residues from liquid and photoresist that can adversely affect photoresist patterning, feature size, and other aspects. At least three different defect mechanisms have been identified

[0007]First defect mechanism is contamination of immersion fluid with soluble species from photoresist which can cause problems in subsequent processing

The second defect mechanism is that the liquid has an adverse effect on the photoresist, causing uneven heat absorption and evaporation during post-exposure baking, which will cause different temperature distributions in different parts of the wafer

The third defect mechanism is that the liquid diffuses into the photoresist and limits the chemical amplification reaction (CAR) used in the subsequent photolithography process

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