Underlayer composition and method of imaging underlayer
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Solution Overview
Problem
Current methods for forming patterns using block copolymers lack the ability to adjust surface polarity lithographically, limiting the formation of patterned surfaces for self-assembling layers without requiring complex polymerization mechanisms or end-group functionalization.
Innovation Solution
A method involving an acid-sensitive copolymer underlayer with an acid decomposable group, an attachment group, and a functional group, combined with a photoacid generator, where irradiation generates acid to form polar regions on the surface, allowing a block copolymer to self-assemble into patterned domains aligned with the polar regions, and subsequent removal of domains to expose the underlying surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If end-group functionalization or reactive-group containing monomers are incorporated in the brush copolymer to provide functional sites for grafting, then the ability to form patterned surfaces is improved, but the device complexity and manufacturing difficulty increase due to requiring complex polymerization mechanisms
Solution Approach 1:
The patent changes the chemical parameter of the copolymer composition by incorporating acid-labile groups (such as t-butyl groups) into the brush copolymer structure. This allows the surface properties to be dynamically changed through acid exposure, enabling pattern formation without complex polymerization mechanisms. The acid-labile groups decompose upon acid exposure to create polar regions that direct block copolymer self-assembly.
2Ease of manufacture
If the brush copolymer composition is adjusted to change surface polarity lithographically, then the ease of manufacture is improved, but the manufacturing precision may be affected due to lack of control over pattern formation
Solution Approach 1:
The patent introduces an intermediary acid-labile group that acts as a mediator between the brush copolymer and the desired pattern. This group can be easily incorporated into the copolymer composition and subsequently activated by acid exposure to create well-defined polar regions. The intermediary enables both easy manufacture through simple composition adjustment and precise pattern control through the defined acid response.
3Manufacturing precision
If photolithographic processes are used to form patterns, then the manufacturing precision is improved, but the productivity decreases due to the multi-step process requirements
Solution Approach 1:
The patent extracts the pattern formation capability from the complex photolithographic process by incorporating photoacid generators directly into the brush copolymer structure. This allows the pattern formation to be achieved through a single irradiation step that simultaneously activates the acid-labile groups, eliminating the need for separate photolithographic steps while maintaining precision.
4Manufacturing precision
If random copolymers of repeating units of each block are synthesized to achieve desired composition, then the manufacturing precision is improved, but the device complexity increases due to synthesis feasibility constraints
Solution Approach 1:
The patent changes the approach to composition control by using acid-labile groups that can be incorporated into the copolymer structure through simpler polymerization methods. The desired composition is achieved not through complex block-by-block synthesis but by controlling the incorporation of acid-labile monomers during polymerization, which then provide the necessary surface properties after acid exposure.
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
Enables the formation of well-defined, self-assembled patterns on a substrate without the need for complex polymerization mechanisms, allowing for precise control over surface energy and pattern formation, enhancing the efficiency of directed self-assembly processes.
Implementation Method 1
irradiating a portion of an underlayer comprising an acid sensitive copolymer comprising an acid decomposable group, an attachment group, and a functional group, and a photoacid generator, wherein the acid decomposable group reacts with an acid generated from the photoacid generator in the irradiated portion of the underlayer
Data Source
AI summary
A method of forming a pattern comprises diffusing an acid, generated by irradiating a portion of a photosensitive layer, into an underlayer comprising an acid sensitive copolymer comprising an acid decomposable group and an attachment group, to form an interpolymer crosslink and/or covalently bonded to the surface of the substrate. Diffusing comprises heating the underlayer and photosensitive layer. The acid sensitive group reacts with the diffused acid to form a polar region at the surface, in the shape of the pattern. The photosensitive layer is removed to forming a self-assembling layer comprising a block copolymer having a block with an affinity for the polar region, and a block having less affinity than the first. The first block forms a domain aligned to the polar region, and the second block forms a domain aligned to the first. Removing either the first or second domain exposes a portion of the underlayer.