Hybrid Hard Mask Structure for Fine Semiconductor Patterning
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Solution Overview
Problem
As the degree of integration of semiconductor devices increases, there is a need for finer patterns with reduced design rules, which existing technologies struggle to achieve effectively due to limitations in forming fine and uniform patterns with precise spacing and shape.
Innovation Solution
A hybrid hard mask structure is employed, comprising alternating first and second hard mask patterns made of silicon oxide and polysilicon, respectively, with tapered opening units arranged in a zigzag pattern, allowing for precise etching of hole patterns in a target layer without bridges between adjacent holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing patterning technologies are used, then the fabrication process is simpler, but the pattern fineness and uniformity deteriorate
Solution Approach 1:
The hard mask pattern is divided into multiple segments (first hard mask pattern and second hard mask pattern) that are formed separately and then combined. This segmentation allows each part to be optimized independently for fine pattern formation while maintaining overall process feasibility, resolving the contradiction between pattern fineness and process complexity
Solution Approach 2:
The patent introduces a vertical dimension by forming opening units at different positions within the hard mask structure (first opening units in the first hard mask pattern, second opening units in the second hard mask pattern). This multi-level approach enables finer horizontal patterning by utilizing vertical stack architecture, achieving high-resolution patterns without proportionally increasing process complexity
2Manufacturing precision
If additional spacing structures are added, then the spacing precision improves, but the device complexity increases
Solution Approach 1:
The patent merges the spacing function into the hard mask pattern itself by alternately arranging first and second hard mask patterns with different refractive indices. The spacing between opening units is naturally defined by the hard mask structure geometry rather than requiring separate spacing structures, achieving precise spacing control while reducing overall structural complexity
Solution Approach 2:
The hard mask pattern serves multiple functions simultaneously: it defines the opening positions, controls the spacing between openings, and provides the etch mask for pattern transfer. This multi-functionality eliminates the need for dedicated spacing structures, achieving spacing precision without increasing structural complexity
3Productivity
If the degree of integration is increased, then the device functionality improves, but the pattern formation difficulty increases
Solution Approach 1:
The patent applies local quality by using first and second hard mask patterns with different materials or properties in different regions of the device. This allows optimization of pattern formation in high-density regions while maintaining manufacturability, enabling higher integration degrees without sacrificing pattern formation precision across the entire device
Data Source
AI summary
A method for fabricating a semiconductor device includes forming a plurality of first hard mask patterns separated by a plurality of trenches on a target layer, forming a plurality of second hard mask patterns filling the plurality of trenches, forming a plurality of first opening units in the plurality of second hard mask patterns, forming a plurality of second opening units in the plurality of first hard mask patterns and forming a plurality of patterns using the plurality of first opening units and the plurality of second opening units, which are transferred by etching the target layer.