Blank Mask Substrate Cleaning via Light-Assisted Ion Removal
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Solution Overview
Problem
The miniaturization of semiconductor devices requires advanced lithography techniques, where the cleaning of substrates for blank masks is critical to prevent defects and maintain high resolution, but existing methods fail to effectively remove contaminants and residual ions, leading to degradation of photomask resolution.
Innovation Solution
A two-step cleaning method involving pre-treatment light and a cleaning solution with post-treatment light, using specific wavelengths and intensities to break molecular bonds and form hydroxyl radicals for efficient removal of organic matters and residual ions, ensuring a substrate with low particle and ion contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used, then the cleaning process is simple, but contaminants and residual ions cannot be effectively removed
Solution Approach 1:
The cleaning process is divided into three distinct stages: pre-treatment light irradiation (50-300 nm wavelength), wet cleaning with cleaning solution, and post-treatment light irradiation (50-450 nm wavelength). Each stage targets specific types of contaminants, allowing effective removal of both organic and inorganic contaminants while managing process complexity through systematic segmentation
Solution Approach 2:
The invention changes multiple parameters including light wavelength (50-300 nm for pre-treatment, 50-450 nm for post-treatment), light intensity (25 mW/cm² or more), and cleaning solution composition to optimize contaminant removal. These parameter changes enable precise control over the cleaning effectiveness for different contaminant types
2Manufacturing precision
If multiple light sources are used for uniform irradiation, then cleaning effectiveness improves, but light intensity uniformity becomes harder to control
Solution Approach 1:
The invention positions multiple light sources at specific locations around the substrate to ensure uniform irradiation across the entire surface. The light sources are arranged to compensate for edge effects and intensity variations, with each source optimized for its local region while contributing to overall uniformity
Solution Approach 2:
The system includes sensors that detect light intensity distribution across the substrate surface and provide feedback to the control unit. The control unit adjusts the intensity of individual light sources to maintain uniform irradiation, automatically compensating for variations and ensuring consistent cleaning quality
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 achieves a high Particle Removal Efficiency (PRE) of 90% or more and effectively reduces residual ions, enhancing the substrate's flatness and optical properties, thereby improving the resolution and reliability of the blank mask.
Implementation Method 1
irradiating a cleaning target substrate with a pre-treatment light to prepare a substrate cleaned with light
Implementation Method 2
applying a first cleaning solution and a post-treatment light to the substrate cleaned with light
Data Source
AI summary
A method of cleaning a substrate for a blank mask including: a first cleaning including irradiating a cleaning target substrate with a pre-treatment light to prepare a substrate cleaned with light, and a second cleaning including applying a first cleaning solution and a post-treatment light to the substrate cleaned with light to prepare the substrate for the blank mask, is disclosed.