Semiconductor Patterning with Dual Masks for High-Density Structures
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Solution Overview
Problem
The resolution limits of mainstream photolithography techniques cannot meet the manufacturing requirements of integrated circuits (ICs) with high integration density, posing a challenge in forming sophisticated repetitive structures.
Innovation Solution
A manufacturing method for semiconductor structures involves forming first and second mask patterns on a target layer, with each mask pattern set at specific orientations and spacings, allowing for separate etching processes to create a high-density repetitive structure, reducing the need for high-resolution photolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mainstream photolithography technique is used, then manufacturing process is simple, but resolution cannot meet manufacturing requirement of high integration density IC
Solution Approach 1:
The patent divides the formation of repetitive structures into multiple etching steps with different mask patterns. Instead of forming all structures in a single photolithography step, the process segments the patterning into: (1) forming first mask patterns, (2) forming second mask patterns that extend along the first direction and cover parts of first mask patterns, (3) performing first etching based on second mask patterns, and (4) performing second etching based on first mask patterns. This segmentation allows achieving high resolution structures beyond photolithography limits.
Solution Approach 2:
The patent introduces a second directional dimension for mask patterns. The second mask patterns extend along the first direction (parallel to first mask patterns) while also having spacing in a second direction perpendicular to the first direction. This dimensional approach allows the etching process to create complex repetitive structures that cannot be achieved with single-direction photolithography patterning.
2Productivity
If photolithography resolution limit is accepted, then manufacturing cost is low, but integration density cannot be increased
Solution Approach 1:
The patent performs preliminary patterning actions by forming mask patterns at larger dimensions that are then used to guide subsequent etching processes. The first and second mask patterns are formed with dimensions that can be achieved by current photolithography, and these masks serve as templates for creating the final high-density repetitive structures through controlled etching, effectively preparing the structure in advance for further refinement.
Solution Approach 2:
The mask patterns serve as intermediary elements between the photolithography process and the final structure formation. The first mask patterns and second mask patterns act as mediators that transfer the pattern from the lithography step to the etching step, allowing the creation of structures with dimensions smaller than what can be directly patterned by photolithography alone.
3Shape
If single etching process is used, then process time is short, but cannot form sophisticated repetitive structure
Solution Approach 1:
The patent employs periodic action through alternating etching and masking steps. The process cycles between: (1) forming mask patterns, (2) performing etching, (3) forming new mask patterns on the etched structure, and (4) performing another etching step. This periodic repetition of masking and etching actions progressively builds the sophisticated repetitive structure, with each cycle adding another layer of complexity to the final geometry.
Data Source
AI summary
A manufacturing method of a semiconductor structure includes: providing a target layer; forming a plurality of first mask patterns on a top surface of the target layer; forming a plurality of second mask patterns above the target layer, where each of the second mask patterns covers at least a part of a top surface of each of the first mask patterns and a part of the top surface of the target layer in an extension direction of the second mask pattern; performing a first etching on the target layer based on the second mask patterns; removing the second mask patterns; and performing a second etching on the target layer based on the first mask patterns.