EUV Photomask Buffer Regions Mitigate Heat Treatment Defects
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Solution Overview
Problem
In semiconductor manufacturing, EUV photomasks face issues with pattern defects due to unintended overlapping exposures during photolithography processes, particularly when the black border region undergoes heat treatment, affecting the reflection of light on the main and scribe lane regions.
Innovation Solution
The introduction of buffer regions outside the scribe lane region, with specific widths and layouts, and corner regions within the black border region, which are strategically positioned to limit and prevent unintended overlapping exposures by adjusting the layout of the buffer and black border regions, thereby mitigating the influence of heat treatment on pattern defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the black border region undergoes heat treatment to improve light reflection control, then pattern defects are reduced, but unintended overlapping exposures occur due to heat influence on main and scribe lane regions
Solution Approach 1:
The mask structure is divided into functionally independent regions: a black border region for light absorption, buffer regions as thermal isolation zones, and scribe lane/main regions for pattern formation. This segmentation prevents heat from the black border region from affecting the pattern-forming regions, eliminating unintended overlapping exposures while maintaining pattern quality.
Solution Approach 2:
Buffer regions are introduced as intermediary zones between the black border region and the scribe lane/main regions. These buffer regions act as thermal mediators that absorb or block heat propagation, preventing the harmful thermal influence from reaching the pattern-forming regions while allowing the black border region to perform its light absorption function.
2Reliability
If buffer regions are introduced to prevent heat treatment influence, then overlapping exposures are reduced, but mask structure complexity increases
Solution Approach 1:
The mask is segmented into distinct functional zones with buffer regions positioned only where thermal isolation is needed (between the black border and pattern regions). This targeted segmentation adds minimal structural complexity while effectively preventing heat-induced overlapping exposures in the critical pattern-forming areas.
Solution Approach 2:
Buffer regions are applied locally only where thermal interference occurs (at the interface between black border region and scribe lane/main regions) rather than uniformly across the entire mask. This localized application maintains exposure accuracy while minimizing the increase in overall mask structure complexity.
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 configuration reduces the occurrence of unintended overlapping exposures, improving pattern quality on semiconductor substrates by limiting the influence of heat treatment on the EUV photomask's reflection performance.
Implementation Method 1
when the black border region undergoes heat treatment, affecting the reflection of light on the main and scribe lane regions
Implementation Method 2
affecting the reflection of light on the main and scribe lane regions
Data Source
AI summary
An extreme ultraviolet (EUV) photomask may include a mask structure including a main region, a scribe lane region surrounding the main region, buffer regions outside the scribe lane region and apart from each other and each having a same first width, and a black border region outside the buffer regions. The buffer regions may include a first buffer region, a second buffer region, and a third buffer region. The black border region may include a first corner region, a second corner region, and a third corner region. The first corner region may contact the first buffer region and the second buffer region. The second corner region may contact the first buffer region, the third buffer region, and a side of the scribe lane region. The third corner region may contact the second buffer region and the third buffer region.