Patternable Brush Layer for Chemoepitaxy
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Solution Overview
Problem
Current directed self-assembly (DSA) processes for block co-polymers in microelectronic manufacturing are complex and costly due to the need for multiple layers and steps, including a separate imaging layer, which increases the risk of defects and reduces yield and throughput.
Innovation Solution
A method and composition where a patternable brush layer, either neutral or non-neutral, is directly patterned and used as a guide layer, eliminating the need for a separate imaging layer by incorporating photo-labile groups and crosslinking monomers to alter surface properties upon exposure, allowing self-assembly of block copolymers directly on the patterned layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional DSA processes use multiple layers including separate imaging layer and neutral brush layer, then the self-assembly pattern can be achieved, but the process complexity and cost increase
Solution Approach 1:
The patent combines the imaging layer and neutral brush layer into a single integrated patternable brush layer. This layer contains both the neutral brush functionality for guiding self-assembly and the photo-labile groups for patterning, eliminating the need for separate imaging layer deposition and processing steps while maintaining pattern precision
Solution Approach 2:
The patternable brush layer serves multiple functions simultaneously: it acts as the neutral brush layer for chemoepitaxy guidance, contains photo-labile groups for lithographic patterning, and provides the surface energy variations needed for block copolymer alignment. This multi-functional layer replaces what were previously separate components
2Manufacturing precision
If conventional DSA processes use multiple intermediate layers, then the pattern transfer can be facilitated, but the manufacturing time and cost increase
Solution Approach 1:
The patternable brush layer integrates the pattern transfer functionality directly into the guide layer. The photo-labile groups undergo chemical changes upon exposure that directly create the surface energy pattern needed for block copolymer self-assembly, eliminating intermediate pattern transfer steps and reducing manufacturing cycle time while maintaining pattern accuracy
3Manufacturing precision
If conventional DSA processes use separate imaging layer that is removed after patterning, then the self-assembly can be directed, but the number of process steps and defect risk increase
Solution Approach 1:
The patternable brush layer maintains its structural integrity and continues to serve as the guide layer throughout the entire process. The photo-labile groups undergo reversible or stable chemical changes that preserve the layer's functionality, eliminating the need for layer removal steps that could introduce defects or damage the underlying structure
4Manufacturing precision
If conventional DSA processes use traditional chemoepitaxy with multiple layers, then the block copolymer alignment can be achieved, but the chemical matching challenges and process length increase
Solution Approach 1:
The patternable brush layer provides universal compatibility by maintaining the neutral brush surface properties needed for block copolymer alignment while incorporating photo-labile groups for patterning. This single layer handles both the chemical guidance function and the patterning function, reducing chemical matching complexity compared to interfacing multiple different layers
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 simplifies the DSA process, reduces complexity and cost, and enhances yield by eliminating the need for additional layers and steps, while maintaining the ability to achieve precise nanoscale patterns with improved thermal stability and solvent resistance.
Implementation Method 1
The patternable layer is exposed to radiation so as to selectively alter the initial surface property to yield an altered surface property at the areas of exposure
Implementation Method 2
The composition is caused to self-assemble into a self-assembled layer in response to the initial surface property, the altered surface property, or both
Data Source
Figure 1(A)~1(D)
Figure 2
Figure 3~4
AI summary
The present invention is broadly concerned with materials, processes, and structures that allow an underlayer to be imaged directly using conventional lithography, thus avoiding the photoresist processing steps required by prior art directed self-assembly (DSA) processes. The underlayers can be tailored to favor a selected block of the DSA block co-polymers (BCP), depending on the pattern, and can be formulated either to initially be neutral to the BCP and switch to non-neutral after photoexposure, or can initially be non-neutral to the BCP and switch to neutral after exposure. These materials allow fast crosslinking to achieve solvent resistance and possess good thermal stability.