EUV Mask Multi-Layer Capping for Carbon Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Carbon contamination on EUV masks leads to non-uniform critical dimension formation and increased exposure energy requirements, affecting the efficiency and cost of semiconductor manufacturing.
Innovation Solution
A multi-layered capping feature with different carbon solubility properties is applied to the EUV mask, comprising layers with varying carbon solubility and EUV extinction coefficients to minimize carbon buildup and maintain effective EUV transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer capping feature is used on the EUV mask, then the structure is simple and manufacturing is easier, but carbon contamination builds up uniformly leading to non-uniform critical dimension formation and increased exposure energy requirements
Solution Approach 1:
The capping feature is divided into multiple layers (first capping layer and second capping layer) with different materials and carbon solubility properties. This segmentation allows each layer to perform different functions: the first layer provides a carbon sink with high carbon solubility, while the second layer provides a carbon barrier with low carbon solubility, together solving the carbon contamination problem that a single layer cannot address
Solution Approach 2:
Different regions of the capping feature (different layers) are given different material properties and carbon solubility characteristics. The first capping layer has high carbon solubility to absorb carbon contamination, while the second capping layer has low carbon solubility to prevent carbon diffusion. This local differentiation of properties enables precise control over carbon contamination at different depths of the capping structure
2Reliability
If exposure energy is increased to compensate for carbon contamination, then pattern formation can be maintained, but manufacturing efficiency decreases and costs increase
Solution Approach 1:
The multi-layer capping structure is prepared in advance before EUV exposure, with the first capping layer positioned to absorb carbon contamination during the exposure process. This preliminary preparation of the carbon management system allows the mask to maintain optimal performance throughout production without requiring increased exposure energy, thus preserving manufacturing efficiency while ensuring pattern quality
3Manufacturing precision
If a multi-layered capping feature with different carbon solubility properties is used, then carbon contamination is reduced and critical dimension uniformity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The carbon management function is extracted and separated into distinct layers: the first capping layer is specifically designed with high carbon solubility to handle carbon absorption, while the second capping layer is designed with low carbon solubility for barrier function. This extraction of the carbon management function into specialized layers simplifies the design logic compared to attempting to achieve both functions in a single complex material
4Object-affected harmful factors
If carbon solubility varies across capping layers, then carbon buildup is minimized through differential absorption, but material selection and process complexity increase
Solution Approach 1:
The carbon solubility parameter is deliberately changed between layers by selecting different materials: the first capping layer uses materials with high carbon solubility (such as certain metals or metal alloys) to absorb carbon, while the second capping layer uses materials with low carbon solubility (such as oxides or nitrides) to block carbon. This parameter change approach provides a systematic method for controlling carbon contamination through material selection rather than complex structural design
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
The multi-layered capping feature reduces carbon contamination, ensuring consistent critical dimension uniformity and reducing the need for increased exposure energy, thereby enhancing manufacturing efficiency and reducing costs.
Implementation Method 1
A multi-layered capping feature with different carbon solubility properties is applied to the EUV mask, comprising layers with varying carbon solubility and EUV extinction coefficients to minimize carbon buildup
Implementation Method 2
A multi-layered capping feature with different carbon solubility properties is applied to the EUV mask, comprising layers with varying carbon solubility and EUV extinction coefficients
Data Source
AI summary
An extreme ultraviolet (EUV) mask includes a substrate, a reflective multilayer stack on the substrate, and a multi-layer capping feature on the reflective multilayer stack. The multi-layer capping feature includes a first capping layer including a material containing an element having a first carbon solubility and a second capping layer including a material containing an element having a second carbon solubility. The first carbon solubility is different from the second carbon solubility. An element of the material of the first capping layer and an element of the material of the second capping layer have extinction coefficients for EUV radiation having a wavelength of 13.5 nm that are different.