Sub-20 nm Mixed Pitch Patterning via Multi-Material Spacer Etching
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Solution Overview
Problem
Conventional lithographic techniques face challenges in achieving uniformity and fidelity for feature sizes below 20 nm due to poor resolution and rough surfaces, especially when attempting to create sub-resolution lines and connections between them, as they operate beyond the capabilities of conventional photo-lithography systems.
Innovation Solution
A method for substrate patterning involving a multi-line layer with alternating lines of different materials, where etch masks selectively remove and replace lines with fill materials, allowing for non-uniform pitch and advanced patterning options by leveraging differing etch resistivities of the materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithographic techniques are used to pattern features below 20 nm, then the manufacturing process remains simple and well-established, but the resolution and surface uniformity deteriorate due to optical limitations
Solution Approach 1:
The patent applies segmentation by dividing the patterning process into multiple discrete steps: forming initial mandrels, depositing first spacers, removing mandrels, depositing second spacers, and selective removal. This multi-stage approach enables achievement of sub-20 nm pitch precision that cannot be obtained through single-step conventional lithography, while maintaining process control through systematic breakdown of complex patterning operations
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional vertical structuring by forming spacer layers that extend vertically from mandrels. This dimensional transition enables pitch multiplication where the final feature pitch is determined by vertical spacer thickness rather than horizontal lithographic resolution, effectively overcoming optical diffraction limits
2Manufacturing precision
If pitch multiplication techniques are used to achieve sub-20 nm features, then the feature size precision improves, but the process complexity increases significantly
Solution Approach 1:
The patent employs periodic action through repeated cycles of material deposition, pattern transfer, and selective removal. The process alternates between forming protective spacer layers and removing target structures in periodic sequences, enabling systematic achievement of high pitch precision through multiple controlled iterations rather than single complex operations
Solution Approach 2:
The patent uses intermediary materials (spacer layers composed of dielectric materials) as mediators between the lithographically-defined mandrels and the final target pattern. These intermediary spacers serve as temporary structures that define the final feature pitch while being removed after transferring the pattern, simplifying the overall process by decoupling pitch definition from final pattern formation
3Quantity of substance
If sub-resolution lines are created using conventional methods, then the pattern density increases, but the ability to make cuts and connections between lines deteriorates
Solution Approach 1:
The patent applies local quality by selectively removing spacers in different regions to create non-uniform pitch patterns. Through localized etching of specific spacer segments while preserving others, the process enables high pattern density in certain areas while maintaining ease of operation for creating cuts and connections in other areas, achieving both high density and operational flexibility simultaneously
Solution Approach 2:
The patent introduces dynamics by enabling post-deposition modification of the pattern through selective spacer removal. The final pattern is not fixed after spacer deposition but can be dynamically adjusted by removing specific spacer segments, allowing flexible creation of cuts and connections while maintaining high overall pattern density
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 enables the creation of lines with non-uniform pitch, improving resolution and fidelity for features smaller than 20 nm, facilitating advanced patterning and reducing the challenges of pattern collapse in high-density semiconductor designs.
Implementation Method 1
Portions of the first material of the multi-line layer that are uncovered by the first etch mask are removed
Data Source
AI summary
Techniques disclosed herein provide a method for substrate patterning that results in lines of non-uniform pitch (mixed pitch). Techniques can also enable advanced patterning options by selectively replacing lines of material in a multi-line layer. A multi-line layer is formed that has alternating lines of three different materials. One or more etch masks are used to selectively remove at least one uncovered line without removing other uncovered lines. Removed material is replaced with a fill material. Selective removal is executed using an etch mask as well as differing etch resistivities of the different lines of materials.