Low-Temperature Plasma Resist Modification for EUV Lithography
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Solution Overview
Problem
In semiconductor manufacturing, the thinning of resist masks due to modifying processes for improving surface roughness degrades the accuracy of pattern sizes on etched target layers, particularly when using EUV photolithography, as the height of the resist mask becomes insufficient to maintain the preset pattern.
Innovation Solution
A plasma processing method involving the sequential stacking of an organic film, a mask film, and a resist film, where a modifying gas such as H2 or hydrogen halides is used to modify the resist film at a temperature of −20° C or lower, maintaining the photoresist thickness and improving surface roughness without degrading pattern accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a modifying process is performed on the photoresist to improve surface roughness, then the surface roughness is improved, but the thickness of the photoresist becomes smaller
Solution Approach 1:
The patent changes the temperature parameter to −20° C. or lower during the modifying process using H2 plasma. This parameter change suppresses the degradation of photoresist thickness while still achieving surface roughness improvement, thereby resolving the contradiction between improving surface quality and maintaining sufficient thickness.
2Manufacturing precision
If the photoresist thickness is reduced to enable finer processing, then finer processing capability is achieved, but the accuracy of pattern size after etching is degraded
Solution Approach 1:
By setting the processing temperature to −20° C. or lower, the patent maintains photoresist thickness even when processing fine patterns. This temperature parameter change prevents excessive thickness reduction, thereby maintaining pattern size accuracy while still achieving fine processing capability.
3Length of moving object
If the height of the resist mask is thinned to meet miniaturization requirements, then miniaturization is achieved, but the preset pattern cannot be maintained during etching
Solution Approach 1:
The patent applies a modifying process at −20° C. or lower that suppresses photoresist thickness degradation. This maintains sufficient mask height even for miniaturized structures, enabling the preset pattern to be maintained throughout the etching process while achieving miniaturization goals.
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 maintains appropriate processing accuracy of the resist film, preventing the degradation of pattern size accuracy on the etched target layer by minimizing the decrement in photoresist height and enhancing Line Width Roughness (LWR) and Line Edge Roughness (LER).
Implementation Method 1
modifying process of modifying the resist film of the processing target object by plasma of the modifying gas at a processing temperature equal to or less than −20° C.
Data Source
AI summary
A plasma processing method of processing a processing target object, in which an organic film, a mask film and a resist film are stacked in sequence, by plasma includes a process of supplying a modifying gas, which is a H2 gas, a hydrogen halide gas, or a mixed gas containing a rare gas and a H2 gas or a hydrogen halide gas, into a chamber accommodating therein the processing target object in which a preset pattern is formed on the resist film; and modifying process of modifying the resist film of the processing target object by plasma of the modifying gas at a processing temperature equal to or less than −20° C.