EUV Photomask Dielectric Pattern Suppresses Electric Arcs
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the occurrence of pattern defects during extreme ultraviolet (EUV) lithography due to electric arcs caused by exposure of reflective photomask components, leading to particle transfer and defects on the substrate.
Innovation Solution
A photomask design featuring a dielectric pattern on the peripheral region that covers the absorption structure and capping layer, preventing external exposure and reducing the likelihood of electric arcs, thereby minimizing particle-induced defects. This design includes a substrate with a reflection layer, absorption structure, and dielectric pattern, where the dielectric pattern extends along the edge of the substrate to shield the absorption structure and capping layer from external exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the absorption structure and capping layer are exposed on the outer region of the photomask, then the manufacturing process is simplified, but electric arcs occur leading to particle transfer and pattern defects
Solution Approach 1:
A dielectric pattern is formed in advance on the outer region of the photomask, covering the absorption structure and capping layer before the photomask is used for lithography. This preliminary protective structure prevents electric arcs from occurring when the mask is exposed to EUV light, thereby preventing particle transfer and pattern defects while maintaining the simplified fabrication process.
2Reliability
If a dielectric pattern is added to cover the absorption structure on the peripheral region, then electric arcs are suppressed and pattern defects are reduced, but the device complexity increases
Solution Approach 1:
The dielectric pattern is applied locally only to the outer region of the photomask where the absorption structure and capping layer are present, rather than covering the entire mask surface. This localized approach provides the necessary protection against electric arcs and particle transfer while minimizing the increase in overall device complexity and maintaining transparency in the pattern region.
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 dielectric pattern effectively suppresses electric arcs on the photomask's outer region, reducing particle transfer and resulting pattern defects, thus enhancing the reliability of semiconductor device manufacturing by minimizing defects in the photomask and subsequent circuit patterns on the wafer.
Implementation Method 1
As light having an EUV wavelength band is mostly absorbed by refractive optical materials, an EUV lithography generally utilizes a reflective optical system instead of a refractive optical system
Implementation Method 2
an EUV lithography generally utilizes a reflective optical system instead of a refractive optical system. For example, the EUV lithography uses a reflective photomask whose reflective side is provided thereon with circuit patterns supposed to be transferred to a wafer
Data Source
AI summary
Disclosed are photomasks, methods of fabricating the same, and methods of manufacturing semiconductor devices using the same. The photomask comprises a substrate including a pattern region and a peripheral region around the pattern region, a reflection layer on the pattern region and extending onto the peripheral region, an absorption structure on the reflection layer, and a dielectric pattern on the absorption structure on the peripheral region and exposing the absorption structure on the pattern region.