Self-Aligned Double Patterning via Oblique Sidewall Spacers
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Solution Overview
Problem
Current multiple patterning techniques in photolithography require multiple exposures and etch operations, which are inefficient and complex, especially for achieving high feature density in integrated circuit fabrication.
Innovation Solution
The method involves a single exposure to define a primary pattern using intentionally introduced angular surfaces and volume modification techniques, allowing for self-aligned double, triple, or quadruple patterning by creating differentiated components through modified and unmodified regions, reducing the complexity of subsequent processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple patterning techniques (lithography-etch, lithography-freeze) are used to enhance feature density, then manufacturing precision is improved, but device complexity increases due to multiple exposures and etch operations
Solution Approach 1:
The patent employs self-aligned patterning where the first pattern automatically serves as the alignment reference for subsequent patterns. The spacer structures are conformally deposited on the first pattern, ensuring automatic self-alignment without requiring additional alignment operations or complex multi-step lithography processes, thus reducing processing complexity while maintaining high feature density
Solution Approach 2:
The patent divides the patterning process into distinct sequential stages: first pattern formation, spacer deposition, spacer patterning, and repeat cycles. Each stage produces a specific pattern component that combines to form the final high-density pattern, allowing complex patterns to be built from simpler intermediate patterns through systematic segmentation
2Manufacturing precision
If lithography-etch technique is used for double patterning, then manufacturing precision is improved, but productivity decreases due to requiring two exposures and two etch operations
Solution Approach 1:
The self-aligned spacer approach eliminates the need for separate alignment operations between patterns. The spacer automatically forms aligned to the first pattern through conformal deposition, removing redundant alignment steps and reducing total processing time while maintaining high pattern accuracy
Solution Approach 2:
The patent combines multiple patterning functions into a unified self-aligned spacer process flow. Instead of separate lithography-etch cycles for each pattern, the method merges pattern formation and alignment into a single integrated process where spacers are deposited and patterned in sequence, improving productivity without sacrificing precision
3Productivity
If spacer-based patterning is used, then productivity is improved by using single exposure, but device complexity increases due to multiple processing steps
Solution Approach 1:
The self-aligned spacer method uses the first pattern itself as the template for spacer formation. The spacer automatically conforms to the first pattern geometry, eliminating the need for additional lithography masks or alignment operations, thus reducing process complexity while maintaining single-exposure efficiency
Solution Approach 2:
The patent performs preliminary conformal spacer deposition on the first pattern before any spacer patterning occurs. This preliminary action establishes the geometric relationship between patterns in advance, simplifying subsequent processing steps and reducing overall process complexity
Data Source
AI summary
A method including forming a pattern on a surface of a substrate, the pattern including one of discrete structures including at least one sidewall defining an oblique angle relative to the surface and discrete structures complemented with a material layer therebetween, the material layer including a volume modified into distinct regions separated by at least one oblique angle relative to the surface; and defining circuit features on the substrate using the pattern, the features having a pitch less than a pitch of the pattern.