Sidewall Spacer Patterning With Multiple Sacrificial Layers
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Solution Overview
Problem
Existing self-aligned multiple patterning technologies in semiconductor manufacturing are complex and lengthy, especially for forming patterns with different pitches, requiring multilayer stacked film structures and multiple mask structures, which complicates the process and increases production costs.
Innovation Solution
A method involving the formation of core layers with different openings, a sacrificial structure, and sidewall spacers on the semiconductor structure, allowing pattern transfer without additional mask structures, simplifying the process and reducing costs by using sacrificial layers with varying materials like silicon oxide and amorphous silicon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multilayer stacked film structures and multiple mask structures are used to form patterns with different pitches, then pattern density and pitch variation are achieved, but process complexity and manufacturing length increase significantly
Solution Approach 1:
The patent divides the pattern formation process into distinct segments: first forming a mandrel layer with initial patterns, then forming a spacer layer that self-aligns to the mandrel, and finally removing the mandrel to transfer the pattern. This segmentation eliminates the need for multiple mask structures and multilayer stacking, achieving different pitches through a single simplified process flow.
Solution Approach 2:
The patent performs preliminary actions by first forming the mandrel layer with the desired pattern before forming the spacer layer. The mandrel serves as a pre-formed template that guides the subsequent spacer formation, enabling pattern transfer without requiring additional mask structures during the spacer formation process.
2Adaptability or versatility
If multilayer stacked film structures are used to transfer patterns layer by layer, then patterns with different pitches are formed, but production time and process length increase
Solution Approach 1:
The patent merges the pattern formation and pitch multiplication steps into a single integrated process. By forming the spacer layer that self-aligns to the mandrel and then removing the mandrel, the process achieves pattern transfer and pitch variation simultaneously, eliminating the need for separate mask formation and pattern transfer steps for each layer.
Solution Approach 2:
The spacer layer performs self-alignment to the mandrel structure through conformal deposition, eliminating the need for additional alignment steps and mask structures. The mandrel automatically serves as the alignment reference, and the spacer forms precisely where needed without requiring external guidance or multiple processing steps.
3Manufacturing precision
If additional mask structures and core layers are used for pattern transfer, then pattern accuracy is maintained, but manufacturing cost and process steps increase
Solution Approach 1:
The patent extracts and removes the mandrel layer after it has served its purpose as a pattern template. By removing the mandrel after spacer formation, the process achieves pattern transfer without requiring the mandrel to remain as a permanent mask structure, simplifying the final structure and reducing manufacturing complexity while maintaining pattern accuracy.
Solution Approach 2:
The mandrel layer serves as an intermediary structure that enables pattern transfer to the spacer layer. It temporarily holds the pattern information during spacer formation and then is removed, having fulfilled its mediating function. This intermediary approach maintains pattern accuracy without requiring permanent mask structures or additional core layers.
Data Source
AI summary
Semiconductor structures and fabrication methods thereof are provided. The method may include providing a to-be-etched layer; forming a plurality of core layers on the to-be-etched layer, wherein a first opening and a second opening are formed between different adjacent core layers and a width of the first opening is smaller than a width of the second opening; forming a first sacrificial material layer on the to-be-etched layer and the plurality of core layers; forming a second sacrificial layer on a portion of the first sacrificial material layer in the first opening to form a sacrificial structure in the first opening; removing the plurality of core layers after forming the sacrificial structure; forming sidewall spacers on sidewall surfaces of the sacrificial structure after removing the plurality of core layers; and removing the sacrificial structure after forming the sidewall spacers.