Imaging Underlayer Polarity Patterning for Block Copolymer Alignment
Find Innovative SolutionsGenerate Solutions
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 photolithographic processes.
Innovation Solution
A method involving an acid sensitive copolymer underlayer with an acid decomposable group, attachment group, and a photoacid generator is used, where the underlayer is irradiated to generate acid, creating a polar region on the surface, allowing a block copolymer to self-assemble into aligned domains, and one block can be removed to expose the underlying pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If block copolymers are used for self-assembly on a neutral surface, then pattern formation is achieved, but the ability to adjust surface polarity lithographically is lost
Solution Approach 1:
The underlayer is segmented into distinct functional regions: a neutral region for general self-assembly and a polar region for lithographic patterning. This is achieved by incorporating acid-decomposable groups (such as t-butyl groups) that can be selectively removed by photolithography to create patterned polar regions, while the remaining areas maintain neutral properties for block copolymer self-assembly.
Solution Approach 2:
The underlayer exhibits different local properties: neutral regions that promote isotropic self-assembly and polar regions that provide anisotropic guidance for domain orientation. The polar regions are created locally through photolithographic decomposition of acid-sensitive groups, enabling spatially controlled surface polarity that guides block copolymer domain alignment in specific areas while leaving other areas neutral.
2Manufacturing precision
If photolithography is used to create patterned surfaces, then manufacturing precision is improved, but the process complexity increases
Solution Approach 1:
The underlayer is pre-functionalized with acid-decomposable groups (such as t-butyl groups) and photoacid generators before the self-assembly step. This preliminary preparation enables subsequent photolithographic patterning to directly create the desired surface polarity pattern without requiring additional complex processing steps. The photoacid generator is incorporated into the underlayer matrix, so when exposed to light, acid is generated in situ to decompose the acid-sensitive groups and create the polar pattern.
Solution Approach 2:
The acid-decomposable groups (such as t-butyl groups) and photoacid generators serve as intermediaries between the photolithography process and the final surface polarity pattern. Upon irradiation, the photoacid generator produces acid that decomposes the acid-sensitive groups, transforming the neutral surface into a polar patterned surface. This intermediary mechanism enables precise pattern transfer from the photolithographic exposure to the underlayer surface properties.
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 enables the formation of precise, patterned surfaces for self-assembling block copolymers without the need for photolithography, allowing for efficient creation of aligned domains and underlying patterns, enhancing the flexibility and precision in semiconductor device manufacturing.
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, the attachment group being covalently bonded to a hydrophilic surface of a substrate, crosslinked to form an interpolymer crosslink, or both covalently bonded to the surface of the substrate and crosslinked to form an interpolymer crosslink, 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.