EUV Mask Fabrication Etching Process
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Solution Overview
Problem
The challenge in extreme ultraviolet lithography (EUVL) is to minimize process disturbance and particle generation during the etching of absorption layers in EUV masks, which is crucial for maintaining high resolution and reducing complexity in IC manufacturing.
Innovation Solution
A method for fabricating EUV masks involves forming a reflective multilayer, a buffer layer, an absorption layer, and a capping layer, with a one-step or multi-step etching process using specific etching chemistries and parameters to etch the capping and absorption layers, reducing process disturbance and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multi-step etching processes are used to etch the absorption layer, then etching precision can be maintained, but process disturbance and particle generation increase
Solution Approach 1:
The patent combines multiple etching steps into a single etching process that simultaneously etches both the capping layer and the absorption layer. This merging of operations reduces the number of process transitions, thereby minimizing process disturbance and particle generation while maintaining etching precision through optimized etching parameters and chemistry selection.
Solution Approach 2:
The patent implements a continuous one-step etching process that continuously removes both the capping layer and absorption layer without interruption or process changes. This continuous action eliminates the start-stop nature of multi-step processes, reducing process disturbance and particle generation while maintaining consistent etching quality throughout the operation.
2Manufacturing precision
If multiple etching steps are used to etch the capping layer and absorption layer separately, then etching control is improved, but process complexity increases
Solution Approach 1:
The patent merges the separate etching processes for the capping layer and absorption layer into a single integrated etching step. By carefully selecting etching chemistry and parameters that provide appropriate selectivity between layers, the patent achieves effective control over both layers' etching while dramatically simplifying the overall process from multiple steps to one continuous operation.
Solution Approach 2:
The patent optimizes etching parameters including gas composition, pressure, power, and temperature to achieve the desired etching control in a single step. By adjusting these parameters, the process maintains precise control over the etching of different layers without requiring multiple process steps, thereby reducing complexity while preserving manufacturing precision.
3Loss of substance
If conventional etching processes are used, then complete removal of the capping layer is achieved, but process disturbance increases
Solution Approach 1:
The patent employs a continuous one-step etching process that continuously removes the capping layer and absorption layer without process interruptions or chemistry changes. This continuous action completes the capping layer removal efficiently while minimizing process disturbance that would occur with repeated process transitions, pump-downs, and chemistry exchanges in conventional multi-step processes.
Solution Approach 2:
The patent combines the capping layer removal with the absorption layer etching in a single integrated process step. This merging ensures complete capping layer removal while avoiding the process disturbance associated with separate etching steps, as the continuous process maintains stable conditions throughout the entire removal and etching operation.
Data Source
AI summary
A method of fabricating an extreme ultraviolet (EUV) mask is disclosed. The method includes providing a substrate, forming a reflective multilayer (ML) over the substrate, forming a buffer layer over the reflective ML, forming an absorption layer over the buffer layer and forming a capping layer over the absorption layer. The capping layer and the absorption layer are etched to form the EUV mask.