Substrate Cleaning Nozzle Mixing to Limit Hydrogen Peroxide Loss
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in maintaining effective concentrations of sulfuric acid and hydrogen peroxide in the SPM, leading to reduced resist removal efficiency due to decomposition at higher temperatures and repeated reuse.
Innovation Solution
A substrate processing apparatus that includes a sulfuric acid-containing liquid supply device and a hydrogen peroxide water supply unit, where the sulfuric acid concentration and temperature are adjusted within specific ranges to prepare a sulfuric acid-containing liquid, which is then mixed with hydrogen peroxide water to maintain effective resist removal capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the SPM is heated to a higher temperature to increase resist removal capability, then the resist removal efficiency is improved, but the hydrogen peroxide decomposes into water and oxygen causing concentration reduction
Solution Approach 1:
The patent applies preliminary action by pre-heating the sulfuric acid-containing liquid separately before mixing with hydrogen peroxide water. The sulfuric acid-containing liquid is heated to the target temperature range (90°C to 250°C) in advance, and then mixed with cold or room-temperature hydrogen peroxide water immediately before substrate processing. This ensures the mixed SPM reaches the required temperature without prolonged exposure that would cause hydrogen peroxide decomposition, thus maintaining both high resist removal efficiency and adequate hydrogen peroxide concentration.
Solution Approach 2:
The patent segments the SPM preparation process into separate heating and mixing stages. The heating function is applied only to the sulfuric acid-containing liquid in a separate circulation system, while the hydrogen peroxide water is kept at or near room temperature. The two components are mixed immediately before use, ensuring the final SPM achieves the required temperature without excessive thermal exposure that would decompose hydrogen peroxide. This segmentation resolves the contradiction by allowing high temperature operation while preserving hydrogen peroxide concentration.
2Loss of substance
If the SPM is repeatedly recovered and reused to reduce waste, then resource efficiency is improved, but the concentrations of sulfuric acid and hydrogen peroxide are reduced to inappropriate levels
Solution Approach 1:
The patent applies parameter changes by adjusting the temperature of the sulfuric acid-containing liquid to a high range (90°C to 250°C) before mixing with hydrogen peroxide water. This temperature parameter change activates the oxidizing power of the SPM, enabling effective resist removal even when the SPM is reused multiple times. The high temperature compensates for the gradual concentration reduction during repeated use, maintaining effective performance without requiring frequent replacement of the SPM solution.
Solution Approach 2:
The patent implements continuous circulation and reuse of the sulfuric acid-containing liquid through a circulation system with pumps and heat exchangers. The liquid is continuously heated, mixed with hydrogen peroxide water, used for substrate processing, and then recovered and reused. This continuous cycle maximizes the utilization of the sulfuric acid-containing liquid, reducing waste while maintaining effective concentrations through controlled temperature and mixing parameters.
3Temperature
If the SPM is circulated continuously to maintain temperature but not spouted for an extended period, then temperature stability is improved, but the SPM may cool down or require constant energy input
Solution Approach 1:
The patent applies preliminary action by pre-heating the sulfuric acid-containing liquid to the target temperature range before mixing with hydrogen peroxide water. The heated sulfuric acid-containing liquid is then mixed with cooler hydrogen peroxide water immediately before substrate processing, ensuring the final SPM reaches the required temperature without requiring prolonged circulation or continuous high energy input during idle periods.
Solution Approach 2:
The patent implements dynamic control of the circulation system, adjusting the circulation rate and heating intensity based on operational needs. During active substrate processing, the circulation maintains temperature stability with optimized energy consumption. During idle periods, the system can reduce circulation rate or heating intensity while maintaining readiness through the pre-heated sulfuric acid-containing liquid reservoir, balancing temperature stability with energy efficiency.
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 ensures efficient resist removal from substrates by maintaining optimal sulfuric acid and hydrogen peroxide concentrations, reducing the need for frequent SPM replacement and minimizing operational costs.
Implementation Method 1
mixing the sulfuric acid-containing liquid and hydrogen peroxide water together in the mixing portion to prepare SPM
Implementation Method 2
the sulfuric acid-containing liquid is circulated through the second tank and the first pipe. A first heater of the second liquid storage heats the sulfuric acid-containing liquid circulated through the second tank and the first pipe
Implementation Method 3
hydrogen peroxide is liable to decompose into water and oxygen at a higher temperature
Data Source
AI summary
The substrate processing apparatus includes: a nozzle having a spout and adapted to spout SPM from the spout toward a substrate; a mixing portion communicating with the spout; a sulfuric acid-containing liquid supply device which recovers liquid supplied to and expelled from the substrate held by a substrate holding unit, prepares a sulfuric acid-containing liquid from the recovered liquid, and supplies the prepared sulfuric acid-containing liquid to the mixing portion; and a control device. The control device performs: a sulfuric acid-containing liquid preparing step of recovering SPM supplied to and expelled from the substrate and preparing the sulfuric acid-containing liquid; and an SPM spouting step of supplying the prepared sulfuric acid-containing liquid and hydrogen peroxide water to the mixing portion, mixing the sulfuric acid-containing liquid and hydrogen peroxide water together in the mixing portion to prepare SPM, and spouting the prepared SPM from the spout.