Substrate Processing Drain Box Venting to Prevent Silica Precipitate
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Solution Overview
Problem
The formation of precipitates in the drain box and drain line of substrate processing apparatuses due to the reaction between silica-containing etching solutions and air leads to blockage and damage of lines and valves.
Innovation Solution
The apparatus incorporates spray members that provide gas and/or liquid to block air ingress and maintain humidity, using nitrogen gas, deionized water, or phosphoric acid to suppress precipitate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphoric solution containing silica is used to etch nitride layer, then etching process is effective, but precipitate is generated in drain box and drain line
Solution Approach 1:
The patent introduces a gas supply system that provides inert gas (nitrogen or air) to the drain box to replace air contact with the etching solution. The gas flows through the drain box to create an inert atmosphere that prevents silica from reacting with air to form precipitates, while maintaining the effectiveness of the phosphoric acid etching process.
Solution Approach 2:
The patent uses gas as an intermediary substance between the etching solution and air. The gas supply member introduces gas into the drain box to act as a barrier medium that prevents direct contact between the silica-containing etching solution and air, thereby preventing precipitate formation without interfering with the etching process.
2Quantity of substance
If precipitate is formed in drain box, then precipitate moves into lines and valves, but blockage and damage of lines and valves occur
Solution Approach 1:
The patent applies preliminary anti-action by preventing precipitate formation before it can cause blockage or damage. The gas supply system is activated during the etching process to continuously prevent silica from reacting with air, thereby eliminating precipitates before they can move into and block the lines and valves.
Solution Approach 2:
By maintaining an inert gas atmosphere in the drain box, the patent prevents the chemical reaction that produces precipitates. This inert environment protects the downstream lines and valves from precipitate-induced blockage and damage, ensuring system reliability.
3Ease of operation
If air is flowed into drain box, then contact between silica and air occurs, but precipitate formation is accelerated
Solution Approach 1:
The patent replaces air with inert gas in the drain box environment. The gas supply member continuously introduces nitrogen or air (in controlled amounts) to maintain an atmosphere that minimizes silica-air contact, thereby reducing the rate of precipitate formation while maintaining ease of operation.
Solution Approach 2:
The introduced gas acts as an intermediary that mediates between the etching solution and ambient air. It creates a protective atmosphere layer that reduces direct contact between silica and air, slowing down precipitate formation kinetics without complicating the operational simplicity of the drain box.
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
Effectively prevents the formation of precipitates by controlling internal pressure and humidity, thereby preventing line and valve blockage and damage.
Implementation Method 1
providing a gas and/or a liquid to block an air flowed into the drain box and/or to control a humidity in the drain box
Data Source
AI summary
An apparatus for processing a substrate may include a drain box for receiving a solution drained in a predetermined process, a drain line for discharging the solution from the drain box to an outside, and at least one spray member for providing a gas and/or a liquid to block an air flowed into the drain box and/or to control a humidity in the drain box.