Semiconductor Lithography Patterning with Dual-Tone Resist Sequencing
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Solution Overview
Problem
The challenge of reducing semiconductor feature size in nanometer technology process nodes is exacerbated by tight process windows in photolithographic processing, necessitating advancements to maintain the ability to scale down semiconductor devices while meeting design criteria for higher device density, performance, and lower costs.
Innovation Solution
A method involving the use of amphoteric photoresists and tri-tone photomasks in extreme ultraviolet lithography, combined with positive-tone and negative-tone developments, to pattern semiconductor devices, allowing for precise and efficient formation of features with varying pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithographic processing is used, then manufacturing process is simple, but manufacturing precision deteriorates due to tight process windows at nanometer nodes
Solution Approach 1:
The patent applies segmentation by dividing the single photolithographic exposure into multiple sequential exposures using a multi-tone photomask. The photomask contains different tone regions (first tone, second tone, third tone) that expose the photoresist to different radiation doses, creating distinct exposed and unexposed regions that can be selectively developed to achieve precise feature patterning at nanometer nodes.
Solution Approach 2:
The patent implements local quality by creating regions with different exposure characteristics within the same photoresist layer. The multi-tone photomask provides different tone levels (first tone with higher exposure, second tone with intermediate exposure, third tone with lower exposure) to different areas of the photoresist, enabling selective development responses in different local regions to achieve the desired precise pattern formation.
2Quantity of substance
If feature size is reduced to increase device density, then device density improves, but process window tightens making patterning more difficult
Solution Approach 1:
The patent applies dynamics by enabling the photoresist to exhibit different development responses based on the cumulative exposure dose received in different regions. The multi-tone photomask creates a dynamic exposure profile where first tone regions receive higher radiation doses, second tone regions receive intermediate doses, and third tone regions receive lower doses, allowing the development process to dynamically respond to these varying exposure levels and produce the desired precise patterns at reduced feature sizes.
Solution Approach 2:
The patent implements parameter changes by utilizing a photoresist composition with specific properties (including glass transition temperature characteristics) that enable it to respond differently to varying exposure doses. The multi-tone photomask changes the exposure parameter (radiation dose) across different regions, and the photoresist's developed solubility changes in response to these parameter variations, allowing precise patterning at nanometer feature sizes.
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
Enhances the ability to form precise patterns in semiconductor devices, addressing the limitations of tight process windows and enabling further reduction in device size while maintaining performance and cost efficiency.
Implementation Method 1
exposed to an energy beam that has itself been patterned. Such an exposure modifies the chemical and physical properties of the exposed regions of the photosensitive material
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a first tone resist layer over an underlayer. The first tone resist layer is pattern to form a first pattern exposing a portion of the underlayer. The first pattern is extended into the underlayer, and the first tone resist layer is removed. A second tone resist layer is formed over the underlayer, wherein the second tone is opposite the first tone. The second tone resist layer is patterned to form a second pattern exposing another portion of the underlayer. The second pattern is extended into underlayer, and the second tone resist layer is removed.