Substrate Drying via Water Removing Agent and IPA Replacement
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Solution Overview
Problem
Existing substrate drying methods fail to effectively replace cleaning water with volatile solvents like IPA, leading to pattern collapse during semiconductor processing due to surface tension issues, which worsens with increasing miniaturization.
Innovation Solution
A substrate processing device and method that includes a cleaning water supply unit, a solvent supply unit for IPA, and a water removing unit to promote the replacement of cleaning water with IPA by using a water removing agent that reacts with water to hydrolyze and reduce surface tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cleaning water is supplied to the substrate surface for cleaning, then the substrate surface is cleaned, but pattern collapse occurs during subsequent drying due to surface tension
Solution Approach 1:
The patent changes the physical-chemical parameter of the liquid from water (high surface tension) to volatile solvent (low surface tension). By selecting a solvent with significantly lower surface tension than water, the harmful capillary forces during drying are reduced, preventing pattern collapse while maintaining cleaning effectiveness.
Solution Approach 2:
The patent utilizes the phase transition property of volatile solvents that evaporate rapidly at room temperature or with mild heating. The quick evaporation minimizes the drying time and reduces the duration of surface tension effects, thereby preventing pattern collapse during the drying process.
2Manufacturing precision
If volatile solvent like IPA is used to replace cleaning water on substrate surface, then pattern collapse is suppressed, but cleaning water cannot be sufficiently replaced without difficulty
Solution Approach 1:
The patent applies preliminary action by first supplying volatile solvent to the substrate surface before complete drying occurs. This preliminary solvent application ensures that water is replaced with low surface tension liquid before the drying phase begins, preventing pattern collapse from the outset rather than attempting to fix it afterward.
Solution Approach 2:
The volatile solvent acts as an intermediary substance that facilitates the transition from water-based cleaning to dry state. By introducing this intermediate liquid phase with favorable properties (low surface tension, high volatility), the system bridges the gap between wet cleaning and dry storage, avoiding the harmful effects of direct water evaporation.
3Manufacturing precision
If more volatile solvent is supplied to ensure complete water replacement, then pattern collapse prevention improves, but processing time and complexity increase
Solution Approach 1:
The patent employs periodic action through controlled, sequential supply of volatile solvent in multiple stages or pulses. Rather than attempting complete replacement in one step, the solvent is supplied periodically to gradually displace water, ensuring thorough replacement while managing processing time efficiently.
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
The solution reliably replaces cleaning water with IPA, effectively preventing pattern collapse during substrate drying and improving semiconductor processing efficiency and productivity.
Implementation Method 1
a water removing unit, and when the solvent supply unit supplies the volatile solvent to the surface of the substrate, the water removing unit supplies a water removing agent to the surface of the substrate, and promotes the replacement of the cleaning water on the surface of the substrate with the volatile solvent
Implementation Method 2
uses IPA (2-Propanol: Isopropyl Alcohol) having a smaller surface tension than the ultrapure water, and mass production factories and the like have employed a method of drying the substrate by replacing the ultrapure water on the substrate surface with the IPA
Data Source
AI summary
A substrate processing device 10 has a water removing unit 110 and, when a solvent supply unit 58 supplies a volatile solvent to a surface of a substrate W, the water removing unit 110 supplies a water removing agent to the surface of the substrate W to promote replacement of the cleaning water on the surface of the substrate W with the volatile solvent.