Topography Directed Patterning Using Block Copolymers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The continuous reduction in feature sizes of integrated circuits poses challenges for high-resolution patterning techniques, as existing methods like X-ray and EUV lithography are expensive and technically complex, and conventional lithography techniques struggle to achieve small feature sizes below 20 nm.
Innovation Solution
The use of block copolymers that self-organize to form masks, combined with pitch multiplication and conventional photolithography, allows for the formation of small, closely-spaced features without the need for expensive high-resolution lithography systems, enabling the creation of features with critical dimensions of 50 nm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography is used to pattern features, then the process is cost-effective and relatively simple, but the feature size cannot be reduced below approximately 20 nm due to resolution limits
Solution Approach 1:
The patent applies segmentation by dividing the patterning process into multiple stages: first forming larger guide features using conventional lithography, then using self-assembling block copolymers to create smaller features between the guide features. This segmentation allows each stage to operate at its optimal resolution level, combining the cost-effectiveness of conventional lithography with the high precision of self-assembly.
Solution Approach 2:
The patent uses self-assembling block copolymers as an intermediary material between the guide features and the final pattern. These copolymers spontaneously organize into periodic structures with dimensions below 20 nm, acting as a mediator that transfers the pattern from the larger guide features to the final high-resolution structure without requiring direct lithographic patterning at that scale.
2Manufacturing precision
If X-ray or EUV lithography is used to achieve high resolution features below 20 nm, then manufacturing precision improves, but cost and technical complexity increase significantly
Solution Approach 1:
The patent employs self-service by utilizing the inherent self-assembling properties of block copolymers to automatically form high-resolution patterns without requiring expensive X-ray or EUV lithography equipment. The copolymers self-organize into periodic structures through thermodynamic driving forces, providing high-resolution patterning (below 20 nm) through a chemically-driven process rather than expensive physical lithography systems.
Solution Approach 2:
The patent uses conventional photolithography to create disposable guide features that serve only to direct the self-assembly of block copolymers. These guide features can be removed after serving their purpose, allowing the use of inexpensive conventional lithography equipment instead of costly X-ray or EUV systems while still achieving the required sub-20 nm resolution through the self-assembling copolymer layer.
3Productivity
If feature sizes are continuously reduced to increase circuit density, then productivity and capacity improve, but the difficulty of patterning increases
Solution Approach 1:
The patent applies dynamics by transitioning from a static lithographic process to a dynamic self-assembling process. The block copolymers are deposited in a disordered state and then undergo spontaneous reorganization into ordered periodic structures through thermal annealing or other stimuli. This dynamic self-organization enables the formation of high-resolution patterns that are difficult to achieve with static conventional lithography methods.
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 reduces costs and increases process reliability by utilizing conventional lithography techniques, enabling the formation of very small features with high precision, facilitating the fabrication of integrated circuits with features as small as 20 nm or less.
Implementation Method 1
depositing a block copolymer material between the spacers, and facilitating self-organization of the block copolymers to form a mask pattern
Implementation Method 2
photolithography involves passing light through a reticle and focusing the light onto a photochemically-active photoresist material. The light or radiation causes a chemical change in the illuminated parts of the photoresist
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A pattern having exceptionally small features is formed on a partially fabricated integrated circuit (102) during integrated circuit fabrication. The pattern comprises features (162), (164) formed by self-organizing material, such as diblock copolymers. The organization of the copolymers is directed by spacers (152) which have been formed by a pitch multiplication process in which the spacers (152) are formed at the sides of sacrificial mandrels (142), which are later removed to leave the spaced-apart, free-standing spacers (152). Diblock copolymers, composed of two immiscible block species, are deposited over and in the space between the spacers (152). The copolymers are made to self-organize, with each block species aggregating with other block species of the same type.