Semiconductor Fine Pattern Formation via Multi-Directional Hard Mask Segmentation
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is forming fine patterns with a reduced pitch and distance between them, which is difficult due to limitations in the photolithography process, especially as design rules become more stringent, leading to issues with pattern formation and etching properties.
Innovation Solution
A method involving the formation of alternating first and second hard mask patterns, followed by the creation of third mask patterns perpendicular to them, with spacers and filling patterns to control opening distances and shapes, allowing for the extension of openings through a lower layer to form zigzag patterns, which can be filled and processed to achieve fine, uniformly spaced patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to form patterns, then pattern formation is achieved, but pattern formation and etching properties deteriorate when pitch is reduced
Solution Approach 1:
The patent segments the pattern formation process into multiple steps: forming first and second hard mask patterns with different pitches, creating third mask patterns perpendicular to them, and using spacer formation to define final fine patterns. This multi-stage segmentation allows achieving fine pitch patterns that cannot be formed by single-step photolithography.
Solution Approach 2:
The patent introduces a second dimensional direction by forming third mask patterns perpendicular to the first and second hard mask patterns. The final fine patterns are created at the intersection of these two directional patterns, effectively using two-dimensional pattern definition to achieve fine pitch that cannot be obtained by one-dimensional photolithography alone.
2Productivity
If pitch between patterns is reduced to increase integration, then element density increases, but pattern formation becomes difficult
Solution Approach 1:
The patent performs preliminary actions by first forming hard mask patterns with larger pitch that can be easily defined by photolithography, then using these as templates for subsequent spacer formation. The spacers are formed conformally on these preliminary patterns and then anisotropically etched to create the final fine patterns, effectively using preliminary larger-pitch patterns to guide the formation of final fine-pitch patterns.
Solution Approach 2:
The patent introduces intermediary structures (third mask patterns and spacers) that mediate between the photolithography-defined hard mask patterns and the final fine patterns. These intermediary elements enable the transfer of pattern definition from larger pitch to finer pitch through controlled etching and spacer formation processes.
3Manufacturing precision
If multiple mask patterns are formed to achieve fine patterns, then pattern precision improves, but process complexity increases
Solution Approach 1:
The patent merges multiple pattern definition functions into a unified process flow where first and second hard mask patterns are formed alternately, third mask patterns are formed perpendicular to them, and spacers are formed on both sidewalls of each filling pattern. This merging of functions into an integrated multi-step process achieves fine pattern precision while managing complexity through systematic process integration.
Data Source
AI summary
A method may include forming first hard mask patterns and second hard mask patterns extending in a first direction and repeatedly and alternately arranged on a lower layer, forming third mask patterns extending in a second direction perpendicular to the first direction on the first and second hard mask patterns, etching the first hard mask patterns using the third mask patterns to form first openings, forming filling patterns filling the first openings and gap regions between the third mask patterns, forming spacers on both sidewalls of each of the filling patterns, after removing the third mask patterns, and etching the second hard mask patterns using the filling patterns and the spacers to form second openings.