Photomask Segmentation for Electric Field Reduction
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Solution Overview
Problem
Current photomasks used in semiconductor manufacturing face challenges in yield and performance due to deformation of critical mask features during the patterning process, primarily caused by electric field-induced material transport and electroforced migration of atoms during spinning processes.
Innovation Solution
The method involves identifying critical mask features exceeding a critical extension and replacing them with a substitutional mask structure comprising two segments separated by a non-printing gap, which reduces the effective electric field strength and prevents material transport, thereby maintaining the original outline of the mask structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If critical mask features with large extension are used in photomask patterns, then the desired pattern coverage and imaging area are achieved, but electric field-induced material transport and electroforced migration occur during spinning processes causing deformation and yield reduction
Solution Approach 1:
The patent divides continuous critical mask features into multiple discrete segments separated by non-printing gaps. This segmentation prevents the formation of continuous conductive paths that would otherwise create strong electric fields during spinning processes, thereby eliminating electroforced migration and material transport while maintaining the overall pattern coverage through strategic placement of segments.
Solution Approach 2:
The patent applies different structural characteristics to different regions of the mask pattern. Critical features that are prone to electroforced migration are segmented with non-printing gaps, while non-critical features maintain continuous structures. This localized application of segmentation ensures pattern fidelity is maintained where needed without unnecessarily complicating the overall design.
2Stability of the object's composition
If continuous mask features are used to maintain pattern continuity, then complete pattern imaging is achieved, but electric field strength increases during spinning causing atom migration and deformation
Solution Approach 1:
The patent segments continuous mask features into discrete portions separated by non-printing gaps. This breaks the continuous conductive path that would allow strong electric fields to form during spinning, thereby preventing electroforced migration while the segmented structure collectively maintains the intended pattern continuity through proper spacing and arrangement of segments.
Solution Approach 2:
The non-printing gaps act as intermediary elements between mask feature segments. These gaps serve as electrical insulators that prevent the formation of continuous electric fields during spinning processes, while optically the segments still function together to maintain the desired pattern continuity on the wafer.
3Length of moving object
If mask features exceed critical extension dimensions, then sufficient imaging coverage is provided, but material transport and deformation occur during manufacturing processes
Solution Approach 1:
The patent divides mask features exceeding critical extension into multiple shorter segments separated by non-printing gaps. Each segment remains below the critical extension threshold, preventing material transport and electroforced migration during spinning, while the collective arrangement of segments provides the necessary imaging coverage and maintains manufacturing precision.
Solution Approach 2:
The patent addresses the length dimension problem by introducing a new dimensional consideration - the vertical stacking of segments. Multiple segments are arranged to collectively provide the equivalent imaging coverage of a single long feature, transforming the problem from a one-dimensional length issue to a multi-segment spatial arrangement that avoids critical dimension thresholds.
4Reliability
If segmented mask structures with non-printing gaps are used, then material transport is prevented and pattern fidelity is maintained, but the mask structure complexity increases
Solution Approach 1:
The patent segments mask features only where necessary to prevent electroforced migration and material transport during spinning. By applying segmentation selectively to critical features rather than uniformly across the entire mask, the design maintains high yield while minimizing the increase in overall structure complexity.
Solution Approach 2:
The patent applies segmented structures with non-printing gaps locally to specific critical features that are susceptible to electroforced migration, while leaving non-critical features as continuous structures. This localized approach maintains pattern fidelity and yield where needed without unnecessarily increasing the complexity of the entire mask structure.
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 approach enhances the yield and performance of photomasks by preventing deformation and maintaining pattern fidelity during the manufacturing of semiconductor devices, ensuring accurate imaging and reduced material transport issues.
Implementation Method 1
electric field-induced material transport and electroforced migration of atoms during spinning processes
Implementation Method 2
electric field-induced material transport and electroforced migration of atoms during spinning processes
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1G
AI summary
First layout data describing a first mask pattern (500) is searched for a critical mask feature (510), wherein the critical mask feature (510) exceeds a critical extension (cl). Second layout data is generated by replacing, in the first layout data, the critical mask feature (510) with a substitutional mask structure (610). The substitutional mask structure (610) includes at least two segments (611) and a non-printing gap (615) separating the segments (611). A second mask pattern (600) described by the second layout data is formed on a base substrate (100) of a photomask (900).