Substrate Rinsing via Inert Gas and pH Control
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Solution Overview
Problem
Existing substrate processing methods fail to adequately prevent metal corrosion on substrates with exposed metal surfaces due to dissolved oxygen and other constituents in rinsing liquids, particularly as existing methods do not effectively address corrosion caused by hydrogen ions and oxygen.
Innovation Solution
A substrate processing method and apparatus that involve replacing the atmosphere around the substrate with an inert gas, adjusting the pH of the rinsing liquid to form an inactive or passive state, and using an organic solvent to replace the rinsing liquid, thereby reducing oxygen concentration and preventing metal corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rinsing liquid is supplied to the substrate to replace chemical liquid, then the substrate is cleaned, but the metal wiring is oxidized by dissolved oxygen in the rinsing liquid causing corrosion
Solution Approach 1:
The patent replaces the atmospheric environment around the substrate with an inert gas atmosphere before supplying rinsing liquid. This prevents oxygen from dissolving into the rinsing liquid and subsequently oxidizing the metal wiring, while still allowing the rinsing liquid to perform its cleaning function effectively
Solution Approach 2:
The patent performs preliminary degassing of the rinsing liquid and preliminary replacement of the atmospheric environment with inert gas before the actual rinsing process. This preliminary action removes dissolved oxygen from the system in advance, preventing corrosion during the subsequent cleaning operation
2Object-affected harmful factors
If the concentration of oxygen in the rinsing liquid is reduced by degassing, then metal corrosion from oxygen is reduced, but corrosion from other constituents like hydrogen ions remains unaddressed
Solution Approach 1:
The patent adjusts the pH of the rinsing liquid to create a passive state on the metal surface or an inactive state where the metal does not react with the rinsing liquid. This parameter change protects against corrosion from hydrogen ions and other constituents beyond just oxygen reduction
3Object-affected harmful factors
If an inert gas is supplied to replace oxygen in the atmosphere, then dissolved oxygen concentration is reduced, but the complexity of the processing system increases
Solution Approach 1:
The patent introduces an inert gas as an intermediary substance between the oxygen-containing atmosphere and the rinsing liquid system. This intermediary prevents direct contact between oxygen and the metal surface through the rinsing liquid, simplifying the overall approach compared to attempting to completely eliminate oxygen from all components
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 method effectively reduces metal corrosion by minimizing oxygen dissolution and adjusting the pH and oxidation-reduction potential of the rinsing liquid to prevent reactive states, ensuring the substrate is protected during processing.
Implementation Method 1
an inert gas replacing step of replacing an atmosphere around the front surface of the substrate with an inert gas by supplying an inert gas to a vicinity of the front surface of the substrate
Implementation Method 2
an adjusting step of adjusting a pH of a rinsing liquid so as to form an inactive state in which the metal does not react with the rinsing liquid or so as to form a passive state by allowing the metal to react with the rinsing liquid
Implementation Method 3
the amount of oxygen that has been dissolved in the rinsing liquid is further reduced by allowing oxygen to move to the atmosphere around the front surface of the substrate from the rinsing liquid so as to maintain a solution equilibrium state
Data Source
AI summary
A substrate processing method includes a substrate holding step of holding a substrate having a front surface on which a metal is exposed, an inert gas replacing step of replacing an atmosphere around the front surface of the substrate with an inert gas by supplying an inert gas to a vicinity of the front surface of the substrate, an adjusting step of adjusting a pH of the rinsing liquid so as to form an inactive state in which the metal does not react with the rinsing liquid or so as to form a passive state by allowing the metal to react with the rinsing liquid, and a rinsing liquid supplying step of supplying the rinsing liquid whose pH has been adjusted to the front surface of the substrate after the atmosphere around the front surface of the substrate has been replaced with the inert gas.