Reflective Photolithography Mask Black Border for Light Leakage Control
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Solution Overview
Problem
In photolithography for semiconductor device fabrication, existing techniques face challenges in achieving high resolution and minimizing light leakage, particularly at the edges and corners of integrated circuit patterns, due to the reflectivity of mask black border regions, which affects the quality of the transferred pattern on wafers.
Innovation Solution
A reflective mask with a phase shift design incorporating a reflective multilayer coating, an absorption layer, and an absorption part in the mask black border region, where the absorption part is filled with nanoparticles to minimize reflectivity and reduce light leakage, enhancing the resolution and contrast of the pattern transferred to the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the mask black border region is made reflective to improve light utilization, then illumination intensity is improved, but light leakage increases causing unwanted exposure
Solution Approach 1:
The mask applies different optical properties to different regions: the mask image region uses reflective multilayer coating for high light utilization, while the mask black border region uses absorption layer with nanoparticles for light absorption. This local differentiation resolves the contradiction by allowing reflective properties where needed while preventing light leakage where harmful.
Solution Approach 2:
The invention converts the potentially harmful reflective property in the mask black border region into a beneficial absorption property by filling the absorption layer with nanoparticles. This transforms what would be light leakage into effective light absorption, eliminating unwanted exposure while maintaining overall light utilization efficiency.
2Illumination intensity
If the mask black border region uses conventional reflective coating to maximize light reflection, then light reflection is improved, but aerial image contrast deteriorates due to light leakage
Solution Approach 1:
The mask structure differentiates between the mask image region and mask black border region, applying reflective multilayer coating only to the image region and absorption layer with nanoparticles to the black border region. This local quality differentiation ensures high light reflection where patterns are formed while preventing light leakage that would degrade aerial image contrast.
Solution Approach 2:
The absorption layer filled with nanoparticles acts as an intermediary between the reflective multilayer coating and the substrate, specifically in the mask black border region. This intermediary layer absorbs stray light that would otherwise leak and degrade aerial image contrast, while allowing the reflective coating to maintain high light reflection in the image region.
3Ease of manufacture
If the mask black border region is left without absorption treatment to simplify manufacturing, then ease of manufacture is improved, but light leakage increases affecting pattern transfer quality
Solution Approach 1:
The mask uses composite materials: reflective multilayer coating (Mo/Si pairs) for the image region and absorption layer filled with nanoparticles (metal, metal oxide, or metal nitride) for the black border region. This composite structure achieves both high pattern transfer quality by preventing light leakage and reasonable manufacturing feasibility through established deposition techniques.
Solution Approach 2:
The invention changes the optical parameters of the mask black border region by introducing an absorption layer with specific nanoparticle fillers. This parameter change transforms the region from potentially reflective to highly absorptive, eliminating light leakage that would degrade pattern transfer quality while using manufacturable nanoparticle incorporation methods.
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 solution effectively reduces unwanted exposure and improves the aerial image contrast during integrated circuit device fabrication, minimizing the impact on critical dimensions and reducing manufacturing time and costs by minimizing light leakage and enhancing printability.
Implementation Method 1
the absorption part is filled with nanoparticles to minimize reflectivity and reduce light leakage
Implementation Method 2
A reflective mask with a phase shift design incorporating a reflective multilayer coating
Data Source
AI summary
A mask includes a reflective layer, an absorption layer, a buffer layer and an absorption part. The absorption layer is disposed over the reflective layer. The buffer layer is disposed between the reflective layer and the absorption layer. The absorption part is disposed in the reflective layer, the buffer layer and the absorption layer.