Single-Chamber Wafer Cleaning and Drying Apparatus
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Solution Overview
Problem
Current semiconductor wafer cleaning and drying processes face challenges in achieving high precision and efficiency, particularly with hydrophobic substrates, due to complications in the structure of existing methods and high chemical consumption, as well as issues with watermarks and residue on dried surfaces.
Innovation Solution
A single-chamber apparatus for cleaning and drying semiconductor wafers that uses a jet-pulse mode with rotating nozzles and continues drying without interrupting substrate rotation, employing IPA and N2 mist for efficient interaction with residual water, allowing for precise cleaning and drying within the same chamber without position change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate cleaning and drying chambers are used, then cleaning and drying functions are well-performed, but device complexity and process time increase
Solution Approach 1:
The patent combines cleaning and drying functions into a single chamber, eliminating the need for separate chambers and substrate transfer. The cleaning unit and drying unit share the same working chamber, reducing device complexity while maintaining functional performance through sequential operation within the unified space.
Solution Approach 2:
The single chamber serves multiple functions: it acts as both the cleaning working chamber and the drying working chamber. The same space accommodates different process units (cleaning unit with spray nozzles, drying unit with heating elements), enabling multi-functionality without requiring separate dedicated chambers for each operation.
2Manufacturing precision
If de-ionized water is sprayed directly onto hydrophobic substrate, then cleaning is performed, but watermarks and residue are formed on the surface
Solution Approach 1:
The patent applies a surfactant solution to the hydrophobic substrate before spraying de-ionized water. This preliminary action modifies the substrate surface properties, improving wettability and preventing water bead formation. The surfactant creates a hydrophilic layer that allows water to spread evenly and be removed without leaving watermarks or residue.
Solution Approach 2:
The surfactant acts as an intermediary substance between the hydrophobic substrate and the de-ionized water. It mediates the interaction by reducing surface tension and improving wetting, allowing the water to effectively clean the surface without forming harmful watermarks or residue that would occur with direct water application.
3Manufacturing precision
If particle-removing method and cleaning chemistry are optimized, then cleaning results improve, but process complexity increases
Solution Approach 1:
The patent divides the cleaning process into distinct functional units: a spray unit for applying cleaning solutions, a rinsing unit for removing contaminants, and a drying unit for eliminating moisture. Each unit is independently controlled and optimized, allowing precise control of particle-removing methods and cleaning chemistry without overwhelming process complexity.
Solution Approach 2:
The patent employs dynamic control of process parameters including spray pressure, flow rate, temperature, and substrate rotation speed. These parameters are adjusted in real-time during the cleaning process to optimize cleaning results while maintaining manageable process complexity through automated control systems.
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 high-precision cleaning and drying of semiconductor wafers with reduced chemical usage and no secondary contamination, ensuring complete dryness and preventing watermarks, thus enhancing the quality and reliability of semiconductor devices.
Implementation Method 1
cleaning is performed in a jet-pulse mode with a cleaning liquid
Implementation Method 2
enhancing formation of droplets of the cleaning medium by increasing the boundary surface area between the jets emitted though the nozzles of the cleaning unit and the surrounding atmosphere
Implementation Method 3
the use of heated liquids or heated gases, such as heated nitrogen gas, during and after rinsing for the removal of unwanted droplets and films from the wafer surfaces
Implementation Method 4
the Marangoni process, which comprises a wet-cleaning process resulting in a completely dried substrate because the substrate is gradually dried directly during extraction of the substrate from the cleaning liquid
Data Source
AI summary
A single-chamber type cleaning-drying apparatus for flat objects, such as semiconductor wafers, wherein cleaning is carried out by impinging both sides of the wafer, which rotates at a relatively low speed, with jets of a washing liquid and wherein subsequent drying is carried out in the same chamber by increasing the rotation speed of the wafer and supplying isopropyl-alcohol (IPA) mist onto the wafer from the top of the chamber. After the IPA forms a solution with the residue of water on the wafer, the drying process is accelerated by supplying gaseous nitrogen through nozzles arranged on both sides of the wafer he coaxially with the wafer center. As a result, the IPA-water solution quickly evaporates without leaving traces of water drops on the dried surface.