Semiconductor Fine Pattern Formation via Hard Mask Etching
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Solution Overview
Problem
The challenge in semiconductor manufacturing is forming fine patterns with a reduced pitch, which is hindered by the resolution limitations of the photolithography process, making it difficult to achieve highly integrated semiconductor devices.
Innovation Solution
A method involving the formation of hard mask patterns in zigzag form using line and space patterns, where first and second hard mask patterns are created with specific pitches and etched to form openings that are transferred to a lower layer, allowing for the formation of fine patterns in a zigzag arrangement, thereby increasing the width of the patterns and optimizing pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to form fine patterns, then manufacturing process is simple, but pattern resolution is limited and fine pitch cannot be achieved
Solution Approach 1:
The patent divides the pattern formation process into multiple stages: first forming initial patterns, then using them as masks to create subsequent patterns. This segmentation allows achieving fine pitch that cannot be obtained through single-step photolithography, resolving the contradiction between manufacturing simplicity and pattern resolution.
Solution Approach 2:
The patent performs preliminary pattern formation and mask creation before final pattern definition. By pre-forming hard masks and sacrificial patterns, the method enables subsequent steps to achieve higher resolution than direct photolithography would allow, addressing the resolution limitation while maintaining overall process feasibility.
2Productivity
If pattern pitch is reduced to increase integration, then device integration increases, but photolithography resolution limitation prevents pattern formation
Solution Approach 1:
The patent transitions from two-dimensional planar patterning to three-dimensional vertical structure utilization. By forming patterns with varying thicknesses and using vertical profiles as masks, the method achieves effective pitch reduction and increased integration density beyond what conventional planar photolithography can provide.
Solution Approach 2:
The patent implements nested pattern formation where smaller patterns are formed within or between larger patterns through multiple masking steps. This nesting approach allows dense packing of features and achieves high integration by effectively reducing the functional pitch between active elements.
3Quantity of substance
If multiple etching steps are performed to form zigzag patterns, then pattern density increases, but process complexity increases
Solution Approach 1:
The patent combines multiple patterning functions into integrated mask structures and consolidated etching steps where possible. By merging the formation of adjacent patterns into single etch operations using shared masks, the method increases pattern density while mitigating the increase in process complexity.
Solution Approach 2:
The patent employs self-aligned patterning where previously formed patterns automatically serve as masks for subsequent etching steps. This self-service approach increases pattern density through precise alignment while reducing the need for additional alignment and masking operations, thereby limiting the increase in process complexity.
Data Source
AI summary
Methods of forming fine patterns are provided. The methods may include forming first hard mask patterns extending in a first direction on a lower layer, forming second hard mask patterns filling gap regions between the first hard mask patterns, forming first 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 first mask patterns as etch masks to form first openings, forming second mask patterns filling the first openings and extending in the second direction, and etching the second hard mask patterns using the second mask patterns as etch masks to form second openings spaced apart from the first openings in a diagonal direction with respect to the first direction.