ClF3 Supply Passage Fluoride Film Coating Method
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Solution Overview
Problem
In film forming operations like CVD and PVD, chlorine trifluoride (ClF3) is adsorbed to uncoated metal surfaces in the apparatus and supply passages, leading to a reduction in ClF3 concentration in the reaction chamber, as previous methods fail to ensure complete fluoride film coverage at welded or fitted connections.
Innovation Solution
A method involving the integral connection of gas supply and discharge passages to a processing chamber, where ClF3 gas at or above the etching process concentration is applied to coat the inner surfaces with a fluoride film before the etching process, ensuring all surfaces are coated, including previously uncoated connection parts, at room temperature to prevent adsorption and maintain ClF3 concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas supply passage is constructed using a metal material with a pre-formed fluoride coating film, then the fluoride film prevents ClF3 adsorption on the pipe surface, but the welded or fitted connection parts remain uncoated and ClF3 is adsorbed at these connection parts
Solution Approach 1:
The patent applies preliminary action by exposing the entire apparatus including all connection parts to ClF3 gas before actual use, forming a fluoride coating film on previously uncoated surfaces. This pre-treatment ensures that welded and fitted connection parts are coated with fluoride film before they come into contact with ClF3 during operation, preventing adsorption at these critical locations.
Solution Approach 2:
The patent utilizes parameter changes by controlling the exposure conditions (ClF3 gas concentration, temperature, exposure time) to form a uniform fluoride coating film on all metal surfaces including connection parts. By adjusting these parameters, the coating process achieves complete coverage without requiring high temperatures that could cause corrosion.
2Productivity
If high temperature is used to form the fluoride film, then the coating process is accelerated, but corrosion occurs inside the pipe
Solution Approach 1:
The patent optimizes the temperature parameter within a specific range (room temperature to 100°C) to achieve effective fluoride film formation without causing pipe corrosion. This parameter optimization allows the coating process to proceed at practical speeds while avoiding the harmful effects of high temperature exposure on the pipe material.
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 prevents ClF3 reduction by ensuring all surfaces are coated with a fluoride film, preventing adsorption and maintaining ClF3 concentration during etching processes, while avoiding high-temperature exposure that could cause corrosion.
Implementation Method 1
ClF3 is likely to be adsorbed to a metal, and easily causes a fluorination reaction on a metal surface
Data Source
AI summary
Provided is a method for treating the inner surface of a chlorine trifluoride supply passage that enables reliable prevention of the reduction in the concentration of ClF3 in a reaction chamber during process operation.The method includes: integrally connecting a gas supply passage (2) and a gas discharge passage (3) to a processing chamber (1) of a processing apparatus in which chlorine trifluoride is used as an etching gas; and applying chlorine trifluoride gas having a concentration equal to or higher than the concentration of chlorine trifluoride gas supplied during etching process operation on inner surfaces of at least the processing chamber (1) and the gas supply passage (2) among the processing chamber (1), the gas supply passage (2), and the gas discharge passage (3), which are integrally formed, to coat the inner surfaces of at least the processing chamber (1) and the gas supply passage (2) with a fluoride film.