Block Copolymer Alignment via Scanning Probe Microscopy
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Solution Overview
Problem
Existing pattern forming methods using directed self-assembly techniques face challenges in accurately measuring and aligning microphase-separation patterns on semiconductor substrates, particularly due to the difficulty in distinguishing hydrophilic and hydrophobic polymer blocks using conventional inspection methods.
Innovation Solution
A method involving the formation of a guide pattern and a block copolymer film on an underlying film, followed by microphase separation, where positions are measured using an atomic force microscope to determine misalignment, allowing for selective removal of misaligned polymer portions and achieving precise alignment of the pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods are used to measure microphase-separation patterns, then the measurement process is simple, but the measurement precision is insufficient to accurately distinguish hydrophilic and hydrophobic polymer blocks
Solution Approach 1:
The patent replaces conventional optical inspection methods with atomic force microscopy (AFM), substituting optical detection with mechanical probing. The AFM uses a physical probe to scan the surface and detect height differences corresponding to hydrophilic and hydrophobic polymer blocks, achieving nanometer-level measurement precision that conventional optical methods cannot provide.
2Measurement precision
If the positions of microphase-separation patterns are measured using atomic force microscope, then the measurement precision is improved, but the inspection time and process complexity increase
Solution Approach 1:
The patent performs preliminary alignment by forming a guide pattern before depositing the block copolymer film. This guide pattern serves as a reference framework that pre-establishes the desired microphase-separation pattern positions, reducing the need for extensive post-processing measurements and adjustments, thereby decreasing total inspection time despite using AFM.
Solution Approach 2:
The block copolymer film performs self-assembly through microphase separation, automatically forming the desired pattern structure based on thermodynamic principles. This self-organizing behavior reduces the need for manual positioning and extensive inspection, as the system self-corrects to achieve the target pattern configuration.
3Manufacturing precision
If misaligned polymer portions are selectively removed to improve alignment precision, then the manufacturing precision is improved, but the productivity decreases due to additional processing steps
Solution Approach 1:
The patent applies partial removal of polymer material by selectively eliminating only the misaligned portions rather than reprocessing the entire structure. This selective approach achieves the necessary alignment precision while minimizing material removal and processing steps, thereby maintaining higher productivity compared to complete re-patterning.
4Manufacturing precision
If multiple measurement and adjustment steps are performed to achieve accurate alignment, then the manufacturing precision is improved, but the manufacturing cost and time increase
Solution Approach 1:
The guide pattern is formed in advance as a reference framework before block copolymer deposition. This preliminary structuring establishes the target alignment positions, enabling more efficient subsequent measurement and adjustment steps by providing a fixed reference against which microphase-separation patterns can be compared and corrected.
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 accurate detection and alignment of microphase-separation patterns, improving the precision of semiconductor device manufacturing by ensuring the correct arrangement of hydrophilic and hydrophobic polymer blocks, even at high temperatures, and reducing manufacturing costs and time.
Implementation Method 1
a step of subjecting the block copolymer film to microphase separation (heating process) and forming a microphase-separation pattern including first and second portions made of the first and second polymers
Implementation Method 2
A position of the guide pattern is measured by using a scanning probe microscope. A positions of the first portion or the second portion is measured by using a scanning probe microscope.
Data Source
AI summary
According to one embodiment, a pattern forming method is disclosed. The method includes forming a guide pattern, forming a block copolymer film that covers the guide pattern and includes first and second polymers, and forming a microphase-separation pattern including first portions of the first polymer and second portions of the second polymer which are alternately arranged by subjecting the block copolymer film to microphase separation. The method further includes measuring a position of the guide pattern, the first portions or the second portions by using a scanning probe microscope, determining whether a misalignment amount of the first portions with respect to the guide pattern is within a first range, based on the measured position of the first and the guide pattern, and removing the first portions, when the misalignment amount is within the first range.