Guide Pattern Surface Modification for DSA CD Uniformity
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Solution Overview
Problem
Directed self-assembly (DSA) lithography techniques face issues with defects and nonuniform Critical Dimension (CD) uniformity in phase-separated patterns due to nonuniform phase separation, leading to DSA errors and inferior pattern quality.
Innovation Solution
A pattern forming method involving the formation of a guide pattern on a substrate, followed by surface modification and coating with a block copolymer that self-assembles into a regular periodic structure, where one component is selectively removed to create a mask for patterning, thereby ensuring uniform phase separation and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If DSA lithography is performed without surface modification on the guide pattern, then the process is simpler, but phase separation becomes nonuniform causing DSA errors and poor CD uniformity
Solution Approach 1:
Surface modification is performed on the guide pattern before coating the block copolymer. This preliminary action ensures that the guide pattern has uniform surface properties (such as through oxidation, silanization, or other chemical treatments), which promotes uniform phase separation of the block copolymer and eliminates DSA errors, thereby achieving the required CD uniformity without compromising process simplicity
2Reliability
If surface modification is performed on the guide pattern, then phase separation uniformity improves, but the process complexity increases
Solution Approach 1:
The surface modification process changes the surface parameters of the guide pattern (such as surface energy, chemical composition, or roughness) through controlled treatments like oxidation, plasma treatment, or chemical vapor deposition. These parameter changes ensure uniform interaction between the guide pattern and block copolymer, achieving reliable phase separation while maintaining reasonable process complexity through standardized treatment protocols
3Productivity
If block copolymer coating is performed without uniform phase separation, then productivity is maintained, but pattern quality deteriorates with DSA errors
Solution Approach 1:
Surface modification is performed as a preliminary step before block copolymer coating to ensure uniform phase separation. This prevents DSA errors and maintains high pattern quality, while the subsequent self-assembly process remains efficient and maintains productivity. The preliminary surface preparation enables the block copolymer to self-assemble uniformly without requiring rework or additional correction 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
The method effectively suppresses DSA errors and improves CD uniformity, resulting in higher pattern quality and reduced production costs by ensuring uniform phase separation and accurate pattern formation.
Implementation Method 1
heating treatment above a substrate coated with a block copolymer that is a self-organizing material to make the block copolymer phase separate at micro-areas so as to form a regular periodic structure
Implementation Method 2
block copolymer that is a self-organizing material to make the block copolymer phase separate
Implementation Method 3
using techniques like washing, cross-linking, or oxidizing to ensure uniform phase separation
Data Source
AI summary
According to one embodiment, first a guide pattern is formed above an object to processing, and then surface modification is performed on the guide pattern. Then a solution including a block copolymer is coated over the object to processing having the guide pattern formed thereon, and the block copolymer is made to phase separate over the object to processing. Subsequently, one component of the phase-separated block copolymer is removed by development. And with the guide pattern coated with other component of the block copolymer as a mask, the object to processing is patterned.