Substrate Processing Apparatus BHF Crystallization Control
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Solution Overview
Problem
The challenge in substrate processing is that buffered hydrofluoric acid (BHF) used in semiconductor wafer processing can crystallize and attach to processing equipment, leading to particle formation on wafers, and subsequent cleaning with deionized water can dilute the BHF, reducing its processing effectiveness and requiring costly recovery and reuse.
Innovation Solution
A substrate processing apparatus with a control unit that executes a cleaning recipe to remove crystallized BHF using deionized water and a return operation to replace residual cleaning liquid with BHF, maintaining the BHF concentration and preventing performance degradation by integrating a recovery channel for BHF reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deionized water is used to clean crystallized BHF from processing equipment, then cleaning effectiveness is improved, but BHF concentration is diluted and processing performance deteriorates
Solution Approach 1:
The system performs a return operation after cleaning to replenish BHF in the processing equipment before subsequent processing begins. This preliminary action ensures that BHF concentration is restored to effective levels before wafers are processed, preventing performance degradation while maintaining cleaning effectiveness.
Solution Approach 2:
The system recovers and reuses the cleaning liquid containing diluted BHF by returning it to the processing equipment through the return channel. This recovery process prevents complete loss of BHF and maintains adequate concentration levels for continued processing operations.
2Loss of substance
If BHF is recovered and reused through the recovery channel, then cost is reduced, but cleaning liquid contamination may occur
Solution Approach 1:
The system executes a return operation that supplies fresh BHF to the processing equipment after cleaning, ensuring that any contaminated recovered liquid does not affect subsequent processing quality. This preliminary replenishment action maintains processing reliability while enabling cost-effective BHF recovery and reuse.
3Manufacturing precision
If cleaning operation is performed frequently to remove crystallized BHF, then particle formation on wafers is prevented, but processing productivity decreases
Solution Approach 1:
The system implements continuous BHF circulation and recovery through the recovery channel, maintaining effective BHF concentration in the processing equipment between cleaning operations. This continuous action reduces the frequency of cleaning operations needed while preventing particle formation, thereby maintaining high processing throughput.
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 effectively prevents particle attachment to wafers, maintains BHF concentration, and optimizes its reuse, thereby enhancing processing performance and reducing costs associated with BHF recovery and maintenance.
Implementation Method 1
cleaning liquid supply part that supplies cleaning liquid to clean the substrate processing part and the liquid drainage part
Implementation Method 2
return operation for supplying the processing liquid from the processing liquid supply part to replace the cleaning liquid that is attached to the substrate processing part and the liquid drainage part with the processing liquid
Data Source
AI summary
A substrate processing apparatus includes a substrate processing part that supplies a processing liquid from a processing liquid supply part to a mounted substrate to execute liquid processing, a liquid drainage part that has a recovery channel connected to a storage part that stores the processing liquid and drains the processing liquid used for the liquid processing, and a control unit executes a processing recipe for the liquid processing and a cleaning recipe for cleaning the substrate processing part and the liquid drainage part. The control unit executes a cleaning operation for supplying a cleaning liquid from a cleaning liquid supply part to clean the substrate processing part and the liquid drainage part and subsequently executes a return operation for supplying the processing liquid from the processing liquid supply part to replace the cleaning liquid attached to the substrate processing part and the liquid drainage part with the processing liquid.