Composite Pattern Formation via Self-Aligned DSA
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Solution Overview
Problem
Current methods for fabricating nanoscale patterns in integrated circuits using directed self-assembly struggle with customizing aperiodic, isolated, or discontinuous features due to the limited resolution of lithography tools, leading to patterning errors that affect device performance, reliability, and uniformity.
Innovation Solution
A method involving a chemical pattern layer with etch-resistant materials is applied, where self-assembling materials form lamellae with alternating domains that align with prepattern features, allowing for selective etching and transfer of patterns to the substrate without additional overlay alignment steps, enabling the creation of composite patterns with customized features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If directed self-assembly is used to generate periodic patterns, then spatial uniformity and density are improved, but customization of aperiodic features becomes difficult
Solution Approach 1:
The prepattern is segmented into two functional types: alignment-conferring prepattern portions (providing periodic structure for self-alignment) and masking feature prepattern portions (enabling customization). This segmentation allows the system to simultaneously achieve spatial uniformity through self-assembly and customization through selective masking, resolving the contradiction between these two requirements.
Solution Approach 2:
Different regions of the prepattern are assigned different local qualities: alignment-conferring portions have properties optimized for directing self-assembly (periodic structure, appropriate pitch), while masking feature portions have properties optimized for pattern customization (different width, position, or composition). This local differentiation enables both uniform periodic patterns and customized aperiodic features to coexist.
2Adaptability or versatility
If lithography tools are used to trim DSA-generated patterns, then customization is achieved, but patterning errors increase due to limited resolution
Solution Approach 1:
Masking features are incorporated into the prepattern before the self-assembly process begins. This preliminary action allows customization to be established at a larger scale where lithography tools can accurately place features, avoiding the need for subsequent high-precision trimming at the nanoscale where DSA domains are formed. The masking features serve as pre-positioned templates that guide the final pattern without requiring post-assembly modification.
3Manufacturing precision
If additional overlay alignment steps are added for customization, then patterning accuracy is maintained, but process complexity increases
Solution Approach 1:
The alignment and customization functions are merged into a single integrated prepattern structure. Alignment-conferring prepattern portions and masking feature prepattern portions are combined in the same layer, allowing both functions to be achieved simultaneously in one self-assembly process without requiring separate overlay alignment steps. This merging eliminates redundant process steps while maintaining patterning accuracy.
Solution Approach 2:
The prepattern serves multiple functions simultaneously: it provides alignment references for self-assembly, defines customized feature locations through masking features, and enables both periodic and aperiodic pattern generation. This multi-functionality eliminates the need for separate dedicated alignment and customization steps, reducing overall process complexity.
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 allows for the generation of precise, customized nanoscale patterns with improved spatial uniformity and reduced patterning errors, enhancing the density and reliability of integrated circuit devices.
Implementation Method 1
The self-assembly of block copolymers, polymer blends, or similar self-assembling materials capable of self-assembling to form regular domains
Implementation Method 2
In chemical epitaxy, an approach to directed self-assembly (DSA) that enables registration of the self-assembled pattern to underlying lithographic layers
Implementation Method 3
One of the first and second materials includes an etch-resistant material such that the first and second materials possess substantially different etch resistances
Data Source
AI summary
A chemical pattern layer including an orientation control material and a prepattern material is formed over a substrate. The chemical pattern layer includes alignment-conferring features and additional masking features. A self-assembling material is applied and self-aligned over the chemical pattern layer. The polymeric block components align to the alignment-conferring features, while the alignment is not altered by the additional masking features. A first polymeric block component is removed selective to a second polymeric block component by an etch to form second polymeric block component portions having a pattern. A composite pattern of the pattern of an etch-resistant material within the chemical pattern layer and the pattern of the second polymeric block component portions can be transferred into underlying material layers employing at least another etch.