EUV Metal-Oxide Resist Development for Collapse-Resistant Patterning
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Solution Overview
Problem
Current EUV lithography techniques face challenges with pattern collapse and non-uniform component distribution in chemically amplified resists, and conventional metal-oxide photoresists are inadequate for patterning features like holes or vias due to their susceptibility to pattern collapse and high aspect ratios.
Innovation Solution
A novel process flow for patterning metal-oxide photoresists using EUV or lower wavelength light, where exposed portions are separated from organic ligands, followed by a bake process and a cyclical plasma development process involving selective deposition and etch steps to develop the pattern, utilizing hydrocarbon or fluorocarbon and hydrogen or halogen based plasmas to create a protective layer and remove exposed portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If chemically amplified resists (CARs) are used in EUV lithography, then sensitivity is improved, but resolution deteriorates due to pattern collapse
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist by using metal-oxide based resists with specific metal elements (Sn, Hf, Zr) and controlled oxide content (30-70 at%), which fundamentally alters the resist's mechanical properties to reduce pattern collapse while maintaining EUV sensitivity
Solution Approach 2:
The patent employs composite material structures by combining metal-oxide clusters with organic ligands in a controlled architecture, creating a hybrid material that exhibits both high sensitivity to EUV light and improved structural integrity to prevent pattern collapse
2Use of energy by moving object
If chemically amplified resists (CARs) are used, then sensitivity is improved, but film uniformity deteriorates due to non-uniform component distribution
Solution Approach 1:
The patent controls the compositional parameters by limiting metal-oxide cluster size (0.5-5 nm diameter) and controlling their density (10^18-10^20 clusters/cm³), which ensures uniform distribution throughout the film while maintaining high sensitivity
3Ease of manufacture
If conventional wet development process is used for metal-oxide photoresists, then process simplicity is maintained, but pattern quality deteriorates for holes or vias
Solution Approach 1:
The patent replaces the wet chemical development process with a plasma-based development process, substituting liquid chemistry with controlled plasma reactions that provide superior precision for patterning holes and vias while maintaining process integration
4Reliability
If metal-oxide photoresists with thin film thickness are used, then pattern collapse risk is reduced, but aspect ratio control becomes more challenging
Solution Approach 1:
The patent optimizes the film thickness parameter to 10-50 nm and controls the metal-oxide cluster size (0.5-5 nm) and density, achieving a balance where the film is thin enough to resist pattern collapse but thick enough to maintain uniform aspect ratio across the patterned features
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 improves pattern performance by reducing line edge roughness and critical dimension errors, enabling effective patterning of metal-oxide photoresists for advanced semiconductor manufacturing, particularly in EUV lithography, with precise atomic layer control and cleaner, cost-effective processes.
Implementation Method 1
EUV or lower wavelength exposure separates organic ligands from metal-oxide structures (e.g., cages or chains) within the exposed portions of the metal-oxide photoresist
Implementation Method 2
a hydrogen or halogen based plasma may be used to selectively convert a surface of the exposed portions of the metal-oxide photoresist into a volatile material (e.g., a metal hydride, halide or chloride), which can be removed for example via ion bombardment
Implementation Method 3
which can be removed for example via ion bombardment
Implementation Method 4
a hydrocarbon or fluorocarbon based plasma may be used in the deposition step to selectively deposit a protective layer (or film) onto the unexposed portions of the metal-oxide photoresist
Data Source
AI summary
Methods are provided herein for patterning extreme ultraviolet (EUV) (or lower wavelength) photoresists, such metal-oxide photoresists. A patterning layer comprising a metal-oxide photoresist is formed on one or more underlying layers provided on a substrate, and portions of the patterning layer not covered by a mask overlying the patterning layer are exposed to EUV or lower wavelengths light. A cyclic dry process is subsequently performed to remove portions of the patterning layer exposed to the EUV or lower wavelength light (i.e., the exposed portions) and develop the metal-oxide photoresist pattern. The cyclic dry process generally includes a plurality of deposition and etch steps, wherein the deposition step selectively deposits a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, and the etch step selectively etches the exposed portions of the patterning layer by exposing the substrate to a second plasma.