Mask Layer Overlap Patterning for Sharp Semiconductor Corners
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Solution Overview
Problem
In semiconductor manufacturing, the reproduction of sharp corners in patterns is challenging due to diffraction effects during lithography and etching, leading to corner rounding and distortion, which affects the critical dimension and functionality of semiconductor devices.
Innovation Solution
A method involving the use of multiple mask layers and patterns, where the first and second mask layers are formed with different materials for etch selectivity, and specific patterns are designed to overlap and intersect to form corners outside the area of the prescribed pattern, preventing rounding during lithography and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single mask layer with rectangular pattern is used, then the manufacturing process is simple, but corner rounding occurs due to diffraction effects
Solution Approach 1:
The patent divides the single mask layer into multiple mask layers (first mask layer and second mask layer), each carrying different pattern information. The first mask layer defines first edges and the second mask layer defines second edges, with their patterns overlapping to form corners outside the prescribed pattern area. This segmentation allows each layer to be optimized independently, preventing corner rounding while maintaining manufacturing feasibility.
Solution Approach 2:
The patent transitions from a two-dimensional single-layer patterning approach to a three-dimensional multi-layer stacking approach. By adding the vertical dimension with multiple mask layers at different heights, the system can define edges and corners in a way that compensates for diffraction effects, placing corner definitions outside the critical pattern area while maintaining process simplicity.
2Manufacturing precision
If multiple mask layers are used to prevent corner rounding, then pattern fidelity is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of defining first edges and second edges into a coordinated multi-layer system where the first mask layer and second mask layer work together. The patterns on both layers are designed to overlap such that corners are formed outside the prescribed pattern area, allowing each layer to contribute to corner sharpness without requiring independent complex structures.
Solution Approach 2:
The patent applies different pattern characteristics to different regions of the mask layers. The first and second patterns are specifically designed with overlapping regions that extend beyond the prescribed pattern boundaries, creating local quality enhancements at corner regions while maintaining standard pattern characteristics in non-critical areas. This localized approach prevents corner rounding without complicating 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 effectively reduces corner rounding, improving pattern fidelity and maintaining sharp corners, thereby enhancing the accuracy and functionality of semiconductor devices by ensuring precise edge formation and critical dimension consistency.
Implementation Method 1
as light bends around corners because of diffraction, patterns with corners are not properly reproduced on the wafer, resulting in a distorted pattern
Data Source
AI summary
A method of reducing corner rounding during patterning of a substrate to form a prescribed pattern comprising a corner includes dividing the pattern into a first pattern and a second pattern, the first pattern forming a first edge of the corner and the second pattern forming a second edge of the corner. At least a portion of the second pattern overlaps the first pattern such that the first edge intersects with the second edge to form a corner of the prescribed pattern. The method further includes forming the first pattern in a first mask layer disposed on a substrate to expose the substrate and forming the second pattern in the first mask layer to expose the substrate. The substrate exposed through the first mask layer is then etched to obtain the pattern.