Discharge Valve Flow Control for Substrate Processing Cleanliness
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Solution Overview
Problem
Existing substrate processing apparatuses suffer from contamination due to the generation of minute particles when valves are opened and closed, leading to poor cleanliness of substrates during processing.
Innovation Solution
A substrate processing apparatus with a discharge valve that changes flow rates by moving a valve element between discharge execution and stop positions, using always-open common, supply, and return piping to minimize particle discharge and ensure cleanliness, along with a suction device to recover processing liquid and prevent dripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a valve is opened and closed to control processing liquid discharge, then discharge control is achieved, but minute particles are generated through valve element rubbing against the valve seat, contaminating the substrate
Solution Approach 1:
The invention extracts the harmful function of the valve (particle generation through rubbing) and replaces it with a valveless system. The discharge control function is achieved through a different mechanism that does not involve valve elements rubbing against seats, thereby eliminating particle generation while maintaining discharge control capability
Solution Approach 2:
The invention replaces the mechanical valve system (with moving valve elements and seats) with a different control mechanism. This substitution eliminates the mechanical rubbing that generates particles, while still achieving the desired discharge control through alternative means
2Productivity
If processing liquid flow is stopped completely, then substrate processing stops, but intermittent dripping occurs affecting processing continuity
Solution Approach 1:
The invention maintains continuous flow of processing liquid through the system at all times, preventing complete stoppage that would cause intermittent dripping. The flow is kept continuous but controlled to appropriate levels, ensuring both processing continuity and stability without interruption
Solution Approach 2:
The invention uses periodic or pulsed flow control mechanisms to regulate processing liquid delivery, maintaining continuous flow at controlled intervals rather than complete stop-start operation, thereby preventing dripping while ensuring adequate processing
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 effectively suppresses contamination by reducing foreign matter in the processing liquid, improving substrate cleanliness and preventing intermittent dripping, while maintaining continuous processing without unnecessary shutdowns.
Implementation Method 1
a suction device which sucks the processing liquid from the branching portion toward the return piping
Data Source
AI summary
The substrate processing apparatus includes common piping which guides a processing liquid to a branching portion, supply piping which guides the processing liquid from the branching portion to a chemical liquid nozzle, return piping which guides the processing liquid from the branching portion, and a discharge valve which changes a flow rate of the processing liquid supplied from the common piping to the branching portion. The discharge valve makes a valve element stationary at a plurality of positions including a discharge execution position at which the processing liquid is supplied from the common piping to the branching portion at a flow rate larger than a maximum value of a suction flow rate and a discharge stop position at which the processing liquid is supplied from the common piping to the branching portion at a flow rate smaller than the maximum value of the suction flow rate.