Semiconductor Cut Patterning with Pitch Relaxation and Ion Enlargement
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Solution Overview
Problem
The challenge of forming integrated circuit patterns with small dimensions is limited by the resolution of exposure tools, leading to the need for multiple photomasks, which increases process errors and fabrication costs, especially when using EUV lithography.
Innovation Solution
A pitch relaxation process is employed to shift cut features apart, allowing them to be printed with a single photomask, followed by ion implantation to enlarge cut features and ensure a sufficient margin for etching, reducing the need for multiple masks and costly EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photomasks are used to form small-dimension patterns, then pattern resolution is improved, but process errors and fabrication costs increase
Solution Approach 1:
The patterning process is divided into two distinct stages: first forming initial patterns with a photomask, then using ion implantation to create additional patterns without requiring a second photomask. This segmentation allows each stage to be optimized independently, reducing cumulative alignment errors while achieving fine pitch patterns.
Solution Approach 2:
An intermediary layer is introduced between the photomask patterning and final pattern formation. This layer undergoes ion implantation to modify its properties, enabling it to serve as a self-aligned mask or pattern definition layer that eliminates the need for precise alignment with additional photomasks.
2Manufacturing precision
If multiple photomasks are used to form small-dimension patterns, then pattern resolution is improved, but fabrication costs increase
Solution Approach 1:
The expensive and error-prone photomask alignment step is extracted and replaced with a self-aligned ion implantation process. By taking out the need for multiple photomasks and their associated alignment procedures, the process eliminates recurring costs while maintaining or improving pattern resolution.
Solution Approach 2:
The process uses a disposable intermediary layer that is intentionally designed to be consumed or modified during ion implantation. This layer serves its pattern definition function temporarily and then fulfills its purpose, replacing the need for expensive, reusable photomasks and their alignment infrastructure.
3Manufacturing precision
If ion implantation is used to enlarge cut features, then etching margin is improved, but process steps are added
Solution Approach 1:
The ion implantation step is merged with the existing patterning workflow by using the same intermediary layer that was already formed during photomask patterning. This combination allows the layer to serve dual purposes: first as a pattern definition layer, then as a material that can be selectively modified by ion implantation to create etching margins, thereby reducing the need for separate process steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces fabrication costs and processing errors while maintaining pattern integrity, enabling the formation of complex circuit patterns with improved lithography printability and etching precision.
Implementation Method 1
performing at least one angled ion implantation to enlarge the first cut feature and the second cut feature
Data Source
AI summary
A method for forming a semiconductor structure includes forming a pattern having first and second line features extending in a first direction on a substrate. After depositing a photoresist layer on the substrate to cover the pattern, the photoresist layer is patterned to form a cut pattern including first and second cut features exposing portions of the respective first and second line features. In a top view, at least one of the first and second cut features is asymmetrically arranged with respect to a central axis of a corresponding first or second line feature. At least one angled ion implantation is performed to enlarge the first and second cut features in at least one direction perpendicular to the first direction. The portions of the first and second line features exposed by the respective first and second cut features are then removed.