Silicon Polymer Inactivation via Inert Atmosphere and Vacuum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for inactivating polymers adhered to the inner surfaces of polycrystalline silicon manufacturing devices pose safety hazards due to the generation of hydrochloric acid gas when silicon tetrachloride is exposed to air, necessitating a safer approach to manage the flammable and unstable polymer byproducts.
Innovation Solution
A method involving a sealable vessel where the polymers are treated with inert gases, partial vacuum, and controlled oxygen addition to convert the polymers into inert silicon dioxide, thereby reducing worker exposure to hazards and safely managing the byproducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon tetrachloride is injected into the exhaust piping to dissolve and remove adhered polymers, then the polymers are effectively removed, but hydrochloric acid gas is generated when the remaining SiCl4 is exposed to air, creating safety hazards
Solution Approach 1:
The patent applies inert atmosphere by filling the reaction furnace with nitrogen gas before and during the polymer removal process. This prevents air from contacting the silicon tetrachloride and polymers, thereby preventing hydrochloric acid gas generation while maintaining effective polymer dissolution. The inert nitrogen environment allows safe handling of reactive chemicals throughout the process.
2Ease of operation
If polymers are exposed to air or moisture to inactivate them, then they can be easily removed, but they spontaneously and violently deflagrate from the heat of hydrolysis, creating extreme safety risks
Solution Approach 1:
The patent maintains an inert nitrogen atmosphere throughout the polymer removal process, preventing contact between polymers and air/moisture. This eliminates the spontaneous deflagration risk while still allowing effective polymer dissolution using silicon tetrachloride, as the reaction occurs in a controlled oxygen-free environment.
Solution Approach 2:
The patent uses nitrogen gas as an intermediary substance that mediates between the polymers and air. The nitrogen creates a protective barrier that prevents direct contact between reactive polymers and oxidizing air, thereby preventing violent reactions while allowing the removal process to proceed safely.
3Productivity
If the reaction rate of polymer treatment is increased to quickly inactivate polymers, then the treatment efficiency is improved, but the risk of deflagration and HCl fume exposure to workers increases
Solution Approach 1:
The patent uses nitrogen inert atmosphere to enable faster polymer treatment rates without increasing worker hazard exposure. The inert environment contains any potential reactions and prevents HCl fume generation, allowing efficient polymer removal while protecting workers from exposure to harmful substances.
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 method effectively converts polymers into inert silicon dioxide, reducing the risk of deflagration and HCl fume exposure, allowing for safe handling and removal of the byproducts without posing risks to workers.
Implementation Method 1
filling the vessel with an inert gas (nitrogen or argon, for example)
Implementation Method 2
pulling a partial vacuum on the vessel
Implementation Method 3
adding a second gas to the vessel to cause a reaction between the second gas and the silicon polymers (the second gas is an oxygen containing gas... whereby the silicon polymers are converted, in whole or in part, to silicon dioxide)
Implementation Method 4
The raw polymers produce HCl gas when exposed to air or moisture. The product becomes unstable when exposed to moisture of any type, becoming hydrolyzed
Data Source
AI summary
A polymer inactivation method for a polycrystalline silicon manufacturing device, wherein the polymer byproducts are treated and additionally treated in a manner that controls the rate of reaction. The polymer byproducts are treated with a first inert gas under partial vacuum and a second oxygen containing gas to convert the polymer byproducts. The reaction rate can be controlled by regulating the fill pressure of reactant gas, controlling the amount of oxygen in the reactant gas, and stripping of the raw polymer with heat and or a vacuum. The solid byproduct remaining after treating the polymer, which is predominately silicon suboxides (SiOx) and silicon dioxide (SiO2), is inert and is easily removed.