Self-Assembled Polymer Lithography Capped Domain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-assembled block copolymers used in lithography face challenges with low etch resistance contrast between domain types, leading to imprecise control of critical dimensions and pattern transfer accuracy due to limited etch resistance contrast and high defect densities.
Innovation Solution
A method involving the formation of a planarization layer over a self-assembled polymer layer with different domain thicknesses, followed by a development etch to create a capped domain structure, which acts as an etch resist to improve pattern transfer accuracy by enhancing etch resistance contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-assembled block copolymers are used as resist layers in lithography, then resolution and pattern density are improved, but etch resistance contrast between domain types deteriorates
Solution Approach 1:
The patent segments the resist layer into distinct first and second domains with different thicknesses. The self-assembled block copolymer naturally forms these segmented domains through phase separation, where one block forms thicker regions and the other forms thinner regions. This segmentation enables selective etching of one domain type while preserving the other, resolving the etch resistance contrast problem.
Solution Approach 2:
The patent applies local quality by creating spatial variation in domain thickness within the resist layer. The first domains have a first thickness while the second domains have a second thickness, allowing different local regions to respond differently to etching processes. This local thickness variation provides the necessary etch resistance contrast for precise pattern transfer.
2Productivity
If self-assembled block copolymers are used to achieve high pattern density, then feature concentration increases, but manufacturing precision deteriorates due to high defect densities
Solution Approach 1:
The patent performs preliminary action by forming a planarization layer over the self-assembled block copolymer resist layer before the etching process. This planarization step pre-compensates for surface irregularities and defect variations, ensuring that subsequent etching proceeds uniformly across the patterned surface. This preliminary planarization improves pattern transfer accuracy despite high pattern density.
3Ease of manufacture
If uniform etching is applied to self-assembled polymer domains, then processing simplicity is maintained, but manufacturing precision deteriorates due to lateral erosion
Solution Approach 1:
The patent changes the physical parameter of domain thickness to create etch resistance contrast. By controlling the self-assembly process to produce first domains with a first thickness and second domains with a second thickness, the patent enables selective etching. This parameter change allows uniform etching chemistry to produce non-uniform etching results, achieving precise critical dimension control without complex processing.
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 method enhances the accuracy of pattern transfer from self-assembled polymer layers to substrates by increasing etch resistance contrast and reducing lateral erosion, allowing for more precise control of critical dimensions and improved lithography results.
Implementation Method 1
self-assemblable block copolymers... may undergo an order-disorder transition on cooling below a certain temperature (order-disorder transition temperature To/d) resulting in phase separation of copolymer blocks
Implementation Method 2
applying a development etch to the planarization layer to substantially remove the second portion leaving at least part of the first portion as a cap
Data Source
AI summary
A method of lithography on a substrate uses a self-assembled polymer (SAP) layer deposited on the substrate, with first and second domains arranged in a pattern across the layer. A planarization layer is formed over the SAP and a development etch applied to substantially remove a portion of the planarization layer over the second domain leaving a cap of the planarization layer substantially covering the first domain. The uncapped second domain is then removed from the surface by a breakthrough etch leaving the capped first domain as a pattern feature on the surface. A transfer etch may then be used to transfer the pattern feature to the substrate using the capped first domain. The capping allows the second domain to be removed, e.g., without excessive loss of lateral feature width for the remaining first domain, even when the difference in etch resistance between the first and second domains is small.