Block Copolymer Self-Assembly for Variable Pitch Lithography
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Solution Overview
Problem
Current methods for forming regularly spaced lithography features require multiple processing steps and cannot efficiently produce features with different pitches using a single type of block copolymer, limiting the density and complexity of nano-scale device structures.
Innovation Solution
A method involving the self-assembly of block copolymers in trenches of varying widths on a substrate, where the block copolymer forms ordered layers with different domain pitches by selectively removing one domain type, allowing for the production of multiple sets of lithography features with varying pitches in a single step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple processing steps are used to form lithography features with different pitches, then feature diversity is improved, but manufacturing complexity and time increase
Solution Approach 1:
The substrate is divided into multiple trenches of different widths, with each trench width corresponding to a specific feature pitch. This segmentation allows different pitch features to be formed simultaneously in different regions without requiring multiple sequential processing steps.
Solution Approach 2:
Each trench is designed with a specific width tailored to the desired feature pitch in that local region. The block copolymer self-assembles differently in each trench based on its local width, producing features with pitches optimized for each specific location on the substrate.
2Length of moving object
If traditional lithography methods are used to reduce feature size, then feature density is improved, but resolution limits are reached due to wavelength constraints
Solution Approach 1:
The block copolymer performs self-assembly within the trenches to automatically form features at the nanoscale. This self-service mechanism eliminates the need for high-resolution projection optics, allowing feature sizes below the diffraction limit to be achieved through the polymer's intrinsic self-organizing behavior.
Solution Approach 2:
The block copolymer undergoes an order-disorder transition when cooled below its order-disorder transition temperature, resulting in phase separation that forms ordered domains with dimensions of tens of nanometers or less. This phase transition mechanism enables precise nanoscale feature formation without conventional lithography resolution limits.
3Ease of manufacture
If a single type of block copolymer is used, then material simplicity is improved, but pitch variation capability deteriorates
Solution Approach 1:
The feature pitch is controlled by changing the physical parameter of trench width rather than changing the block copolymer type. By varying the trench width across different regions of the substrate, a single block copolymer material can produce features with multiple different pitches, maintaining material simplicity while achieving pitch diversity.
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 production of lithography features with pitches as low as 10-40 nm and allows for the creation of multiple FinFETs with different channel pitches on a single substrate, enhancing the density and functionality of nano-scale device structures.
Implementation Method 1
A self-assemblable BCP is a compound useful in nanofabrication because it 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 of different chemical nature to form ordered, chemically distinct domains with dimensions of tens of nanometers or even less than 10 nm.
Implementation Method 2
The use of self-assembly of a block copolymers (BCP) has been considered as a potential method for increasing the feature resolution to a smaller dimension than that obtainable by prior lithography methods
Data Source
AI summary
A method of forming a plurality of regularly spaced lithography features, the method including providing a self-assemblable block copolymer having first and second blocks in a plurality of trenches on a substrate, each trench including opposing side-walls and a base, with the side-walls having a width therebetween, wherein a first trench has a greater width than a second trench; causing the self-assemblable block copolymer to self-assemble into an ordered layer in each trench, the layer having a first domain of the first block alternating with a second domain of the second block, wherein the first and second trenches have the same number of each respective domain; and selectively removing the first domain to form regularly spaced rows of lithography features having the second domain along each trench, wherein the pitch of the features in the first trench is greater than the pitch of the features in the second trench.