Multi-Patterning Semiconductor Fabrication via Mask Overlap
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Solution Overview
Problem
The increasing integration level of semiconductor devices has surpassed the minimum feature resolution capabilities of existing photolithography processes, which are limited by the wavelength of light sources used, making it difficult to achieve finer patterns.
Innovation Solution
The method involves forming multiple mask patterns with overlapping openings to create etched regions on a substrate, allowing for the division of spacers and target patterns into finer features, enabling the fabrication of semiconductor devices with improved resolution by using a combination of hard mask layers and spacer formation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography processes use existing light sources, then the manufacturing process is simple and fast, but the minimum feature resolution cannot achieve finer patterns
Solution Approach 1:
The patent applies segmentation by dividing the pattern formation process into multiple steps using multiple mask patterns (first mask pattern with first openings, second mask pattern with second openings). Each mask pattern creates partial patterns that are combined through overlapping, allowing the final fine patterns to be formed by intersecting multiple coarser patterns. This segmentation enables achieving finer minimum feature resolution that cannot be obtained by a single photolithography exposure.
2Manufacturing precision
If multiple mask patterns with overlapping openings are used to create finer patterns, then the manufacturing precision is improved, but the device complexity and process steps increase
Solution Approach 1:
The patent implements nesting by forming the second mask pattern on top of the first mask pattern structure. The second mask pattern is positioned to overlap with the first mask pattern, creating nested layers of masking. This nested arrangement allows multiple patterning steps to be combined, where the overlapping regions define the final fine patterns, reducing the need for completely separate process steps.
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional overlapping mask structures. By stacking mask patterns in the vertical dimension and using overlapping openings at different layers, the process achieves finer lateral resolution than would be possible with single-layer photolithography. The overlapping regions in the vertical dimension translate to precise pattern definition in the horizontal dimension.
Data Source
AI summary
A method of fabricating a semiconductor device is provided. A plurality of target patterns is formed on a substrate. The plurality of target patterns is extended in parallel to each other along a first direction. A first mask pattern extending in the first direction and including a plurality of first openings is formed. A second mask pattern extending in a second direction crossing the first direction and including a plurality of second openings is formed. Each second opening overlaps each first opening to form an overlapped opening region. A region of the plurality of target patterns is etched through the overlapped opening region using the first mask pattern and the second mask pattern as a etch mask. The region of the plurality of target patterns is overlapped with the overlapped opening region.