Laser Annealing for Directed Self-Assembly Pattern Alignment
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Solution Overview
Problem
Directed self-assembly (DSA) processes in semiconductor lithography face challenges with incomplete annealing leading to defects due to long bake times or high temperature processing, which can damage materials and reduce throughput.
Innovation Solution
Laser annealing is used to optimize lithographic processes by applying controlled temperature and time profiles through varying laser exposure intensity and scanning rates, allowing for precise heating of substrates during DSA, potentially combined with additional techniques like hotplate annealing, to enhance micro-phase separation and pattern alignment without material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If long bake times or high temperature processing is used for annealing, then micro-phase separation and alignment are improved, but material degradation and oxidation occur
Solution Approach 1:
The patent applies periodic pulsed laser irradiation to provide intermittent heating cycles that achieve micro-phase separation and alignment without sustained high temperature exposure. The pulsed nature allows thermal diffusion during each pulse while preventing cumulative thermal damage through controlled intervals between pulses.
Solution Approach 2:
The patent changes the heating parameters from conventional continuous high-temperature processing to controlled pulsed laser heating with specific pulse durations, intensities, and frequencies. This parameter transformation enables achieving the required thermal effect for self-assembly while limiting peak temperature exposure time to prevent material degradation.
2Manufacturing precision
If long bake times are used for annealing, then complete micro-phase separation is achieved, but throughput is reduced
Solution Approach 1:
The patent replaces the conventional thermal conduction-based heating system with a direct optical-to-thermal energy conversion system using laser irradiation. This substitution enables rapid and uniform heating throughout the polymer film thickness, achieving complete micro-phase separation in seconds rather than hours, thereby dramatically improving throughput.
Solution Approach 2:
The patent applies preliminary laser annealing treatment before subsequent lithographic processing steps. By completing the micro-phase separation and alignment in advance using rapid laser heating, the process eliminates the need for prolonged bake times in later stages, thereby increasing overall manufacturing throughput.
3Manufacturing precision
If high temperature baking is used for annealing, then alignment is improved, but oxidation and material damage occur
Solution Approach 1:
The patent introduces an inert or controlled atmosphere as an intermediary medium during laser annealing processing. This atmosphere layer prevents direct contact between oxygen and the polymer material during high-temperature exposure, thereby preventing oxidation while allowing the thermal energy to achieve proper micro-phase alignment.
Solution Approach 2:
The patent replaces conventional convective or conductive heating systems with direct laser irradiation, enabling precise spatial and temporal control of thermal energy delivery. This substitution allows achieving the required temperature for thermodynamic alignment only where and when needed, minimizing overall thermal exposure and reducing the risk of oxidation and material damage.
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
Laser annealing significantly reduces processing time, minimizes defects, and maintains material integrity by enabling precise thermal control, thus improving the quality and efficiency of DSA patterns.
Implementation Method 1
irradiating a substrate and/or structure at a laser wavelength that is substantially absorbed by the substrate and/or structure
Implementation Method 2
a laser wavelength that is substantially absorbed by the substrate and/or structure
Implementation Method 3
causes block co-polymers (BCPs) to micro-phase separate and aligns the micro-domains in a thermodynamically preferred orientation
Data Source
AI summary
Approaches for utilizing laser annealing to optimize lithographic processes such as directed self assembly (DSA) are provided. Under a typical approach, a substrate (e.g., a wafer) will be subjected to a lithographic process (e.g., having a set of stages/phases, aspects, etc.) such as DSA. Before or during such process, a set of laser annealing passes/scans will be made over the substrate to optimize one or more of the stages. In addition, the substrate could be subjected to additional processes such as hotplate annealing, etc. Still yet, in making a series of laser annealing passes, the techniques utilized and/or beam characteristics of each pass could be varied to further optimize the results.