Directed Self-Assembly Block Copolymer Patterning for High Resolution
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Solution Overview
Problem
The miniaturization of semiconductor devices is limited by the thickness of the photoresist layer, which must be sufficient to resist etching processes, making it difficult to achieve high resolution in photolithographic and etching processes without increasing fabrication complexity.
Innovation Solution
A method involving the use of directed self-assembly (DSA) material layers, specifically block copolymers, which are deposited on resist patterns, undergo self-assembling processes to form block copolymer patterns that can be selectively etched to create second resist patterns, allowing for pattern transfer and etching while maintaining or reducing photoresist thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the photoresist layer thickness is reduced to achieve higher resolution, then the pattern resolution is improved, but the photoresist layer becomes insufficient to resist the etching process
Solution Approach 1:
The patent divides the photoresist system into multiple layers: a first photoresist layer for initial patterning and a second photoresist layer for etching protection. This segmentation allows each layer to have optimized thickness - the first layer can be thinner for higher resolution while the second layer provides sufficient etching resistance
Solution Approach 2:
The patent transitions from a single-layer photoresist structure to a multi-layer vertical structure. By adding the dimension of layer stacking, the system achieves both high resolution (through thin first layer) and etching resistance (through thick second layer) simultaneously
2Strength
If the photoresist layer thickness is increased to withstand etching, then the etching resistance is improved, but the pattern resolution deteriorates
Solution Approach 1:
The patent segments the photoresist function into two separate layers: the first photoresist layer optimized for pattern formation with appropriate thickness for resolution, and the second photoresist layer optimized for etching protection with greater thickness
Solution Approach 2:
Different regions of the photoresist system have different thicknesses optimized for different functions: the first layer has thinner thickness for high-resolution patterning in critical areas, while the second layer has thicker thickness for etching resistance in areas requiring protection
3Device complexity
If conventional photolithography and etching processes are used, then the process is simple, but the device miniaturization is limited
Solution Approach 1:
The fabrication process is segmented into distinct stages: first photoresist patterning, then second photoresist layer formation, followed by selective etching. This segmentation enables device miniaturization by allowing independent optimization of pattern resolution and etching protection
Solution Approach 2:
The patent adds vertical layering dimension to the conventional planar photolithography process. This multi-layer vertical structure enables higher device density and miniaturization while maintaining process manageability through sequential processing steps
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 pattern resolution and minimizes the limitations of photolithographic and etching processes, enabling device miniaturization by using ultra-thin photoresist layers and allowing for more precise pattern transfer without increasing fabrication complexity.
Implementation Method 1
The DSA material layer is then subjected to a self-assembling process so as to form repeatedly arranged block copolymer patterns in the DSA material layer
Implementation Method 2
The DSA material layer comprises block copolymers. The self-assembling process is performed at a temperature lower than a glass transition temperature (Tg) of the block copolymers
Data Source
AI summary
A method of forming patterns includes the steps of providing a substrate having a target layer thereon; forming a plurality of first resist patterns on the target layer; depositing a directed self-assembly (DSA) material layer in a blanket manner on the first resist patterns, wherein the DSA material layer fills up a gap between the first resist patterns; subjecting the DSA material layer to a self-assembling process so as to form repeatedly arranged block copolymer patterns in the DSA material layer; and removing undesired portions from the DSA material layer to form second resist patterns on the target layer.