Immersion Exposure Resist Pattern Defect Control
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Solution Overview
Problem
Immersion exposure methods face challenges such as liquid spillage during high-speed stage movement, residual water causing defects, and air bubbles interfering with exposure, leading to resist pattern defects due to incomplete drying and temperature issues.
Innovation Solution
A resist pattern forming method involving the selective formation of a flowing liquid film between the resist film and projection optical system, followed by controlled gas spraying and heating to remove residual water, ensuring complete drying and preventing air bubble interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid is supplied to the entire stage for immersion exposure, then exposure quality is improved, but liquid spills from the stage during high-speed movement
Solution Approach 1:
The patent applies local quality by transitioning from supplying liquid to the entire stage to supplying liquid only to the local exposure area. The liquid supply unit is positioned to deliver liquid precisely where the substrate is being exposed, maintaining immersion exposure benefits while avoiding liquid spillage during high-speed stage movement.
2Speed
If liquid is locally supplied to the exposure area, then stage movement speed is improved, but water remains in the exposure area causing defects
Solution Approach 1:
The patent applies preliminary action by introducing a drying step before the resist development process. The drying unit removes water from the exposure area and surrounding regions before post-exposure heating and development, preventing water marks and resist pattern defects that would otherwise occur due to residual water.
3Productivity
If exposure is performed near the substrate edge, then substrate utilization is improved, but air bubbles are caught in the liquid flow causing exposure troubles
Solution Approach 1:
The patent applies pneumatics and hydraulics by using a gas flow from the drying unit to control liquid flow dynamics. The gas flow directs liquid away from the substrate edge exposure area, preventing air bubble entrapment and ensuring stable exposure even when exposing near the substrate periphery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively suppresses resist pattern defects by ensuring complete drying and uniform heating, maintaining high-speed stage movement and preventing exposure issues at the substrate edges.
Implementation Method 1
transferring the pattern formed on the reticle to the resist film, with the first liquid film being formed, to form a latent image in the resist film
Implementation Method 2
heating the resist film formed the latent image therein after the removal
Implementation Method 3
spraying a gas from a gas injection portion to a part of a surface of the resist film
Data Source
AI summary
In immersion exposure, a resist pattern forming method suppressing resist pattern defects comprises mounting a substrate formed a resist film thereon and a reticle formed a pattern thereon onto an exposure apparatus, supplying a first chemical solution onto the resist film to selectively form a first liquid film in a local area on the resist film and draining the solution, the first liquid film having a flow and being formed between the resist film and a projection optical system, transferring the pattern of the reticle to the resist film through the first liquid film to form a latent image, supplying a second chemical solution onto the resist film to clean the resist film, heating the resist film, and developing the resist film to form a resist pattern from the resist film.