Guided Via Patterning Over Metal Gratings Using Diblock Self-Assembly
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Solution Overview
Problem
Current lithographic processes face challenges in forming small vias with precise alignment and spacing, as they are limited by the resolution capabilities of EUV scanners, leading to variability in line width roughness and critical dimension uniformity, and require multiple masks, which increase costs and complexity.
Innovation Solution
A directed self-assembly (DSA) process using a diblock copolymer with a guiding pattern to form aligned cylindrical structures, where the diblock copolymer is chemically modified to align with underlying structures, allowing for precise hexagonal arrays of vias that are well-aligned with the underlying metal grating, reducing the need for multiple masks and improving alignment precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If EUV lithography is used to form small vias, then via size can be reduced, but alignment precision and critical dimension uniformity deteriorate due to resolution limitations
Solution Approach 1:
A guiding pattern layer is introduced as an intermediary between the substrate and the self-assembling diblock copolymer. This guiding pattern serves as a mediator that directs the self-assembly process to form cylindrical structures with precise alignment and spacing, overcoming the resolution limitations of EUV lithography while maintaining manufacturing precision
Solution Approach 2:
The diblock copolymer performs self-service by automatically self-assembling into cylindrical structures with uniform spacing and alignment when guided by the pattern layer. This self-assembly process eliminates the need for multiple lithographic masks and achieves high precision without additional intervention, reducing both complexity and cost
2Manufacturing precision
If multiple masks are used in lithographic processes, then via formation precision can be improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The diblock copolymer performs self-service by automatically self-assembling into cylindrical structures with uniform spacing and alignment when guided by the pattern layer. This self-assembly process eliminates the need for multiple lithographic masks and achieves high precision without additional intervention, reducing both complexity and cost
Solution Approach 2:
The manufacturing process is segmented into distinct functional layers: a guiding pattern layer that provides structural guidance and a self-assembling diblock copolymer layer that forms the via structures. This segmentation allows each layer to perform its specific function independently, simplifying the overall process while maintaining precision
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
The DSA process enables the formation of highly regular and aligned hexagonal arrays of vias with improved alignment to underlying structures, reducing variability and costs associated with multiple masks, and maintaining high precision in via formation.
Implementation Method 1
a directed self-assembly (DSA) process using a diblock copolymer with a guiding pattern to form aligned cylindrical structures
Implementation Method 2
the diblock copolymer is chemically modified to align with underlying structures
Data Source
AI summary
Described herein are IC devices include vias deposited in a regular array, e.g., a hexagonal array, and processes for depositing vias in a regular array. The process includes depositing a guiding pattern over a metal grating, depositing a diblock copolymer over the guiding pattern, and causing the diblock copolymer to self-assemble such one polymer forms an array of cylinders over metal portions of the metal grating. The polymer layer can be converted into a hard mask layer, with one hard mask material forming the cylinders, and a different hard mask material surrounding the cylinders. A cylinder can be selectively etched, and a via material deposited in the cylindrical hole to form a via.