Tin Oxide Removal in Process Chambers via Hydrocarbon Plasma
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Solution Overview
Problem
Current methods for cleaning tin oxide deposits from process chambers in semiconductor manufacturing are inefficient, particularly at lower temperatures, as they can lead to incomplete removal due to the formation of non-volatile carbon-containing polymers, which impede the etching process and can damage metallic chamber walls.
Innovation Solution
A method involving exposure of the tin oxide layer to a hydrocarbon and hydrogen gas to convert it into a volatile compound, followed by removal of the formed carbon-containing polymer using an oxygen-containing reactant or hydrogen, with optional plasma activation, to facilitate complete tin oxide removal without damaging chamber surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorine-based or hydrogen-based etching methods are used to remove tin oxide deposits, then the etching process can proceed, but non-volatile carbon-containing polymers form and impede the etching process, leading to incomplete removal and potential damage to metallic chamber walls
Solution Approach 1:
The cleaning process uses periodic alternation between hydrocarbon-containing gas (for tin oxide conversion) and oxygen-containing gas (for polymer removal). This periodic switching prevents carbon polymer accumulation by actively removing it during oxygen exposure phases, thereby maintaining etching efficiency and preventing chamber wall damage throughout the cleaning cycle
Solution Approach 2:
The harmful carbon-containing polymer byproduct is converted into a removable intermediate layer. By introducing oxygen-containing gas, the polymer is transformed into a volatile compound that can be easily removed, turning the harmful accumulation effect into a beneficial temporary layer that protects and facilitates the cleaning process
2Productivity
If high temperature is used to remove tin oxide deposits, then the etching process is more effective, but the process becomes less efficient at lower temperatures where polymer formation is more problematic
Solution Approach 1:
The process changes the chemical composition parameter of the cleaning gas by alternating between hydrocarbon-containing and oxygen-containing gases. This parameter change enables effective tin oxide removal at lower temperatures by using oxygen to prevent carbon polymer formation, thereby maintaining etching efficiency without requiring high temperatures
3Temperature
If hydrocarbon and hydrogen gas is used to convert tin oxide to volatile compound, then tin oxide removal is facilitated at lower temperatures, but carbon-containing polymer forms as a byproduct
Solution Approach 1:
The harmful carbon-containing polymer byproduct is extracted and removed from the system by introducing oxygen-containing gas. The oxygen reacts with the polymer to form volatile compounds that are evacuated from the chamber, thereby eliminating the substance loss and preventing polymer accumulation that would impede the cleaning process
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 removes tin oxide deposits at lower temperatures (e.g., 30-120°C) while preventing damage to metallic surfaces, outperforming chlorine-based and hydrogen-based etching methods by periodically removing the carbon-containing polymer, ensuring thorough cleaning and maintaining chamber integrity.
Implementation Method 1
exposing the tin oxide layer in the process chamber to a process gas that includes a hydrocarbon and hydrogen (H2) to convert at least a portion of the tin oxide layer to a volatile compound
Implementation Method 2
wherein the exposure of the tin oxide layer to the process gas that includes a hydrocarbon and hydrogen (H2) further results in a formation of a non-volatile carbon-containing polymer
Implementation Method 3
removing the carbon-containing polymer by exposing the carbon-containing residue to an oxygen-containing reactant or to H2
Data Source
AI summary
Process chambers are cleaned from tin oxide deposits by a method that includes a step of forming a volatile tin-containing compound by exposing the tin oxide to a mixture of hydrogen (H2) and a hydrocarbon in a plasma, followed by a step that removes a carbon-containing polymer that formed as a result of the hydrocarbon exposure. The carbon-containing polymer can be removed by exposing the carbon-containing polymer to an oxygen-containing reactant (e.g., to O2 in a plasma), or to H2 in an absence of a hydrocarbon. These steps are repeated as many times as necessary to clean the process chamber. The method can be used to clean ALD, CVD, and PVD process chambers and is particularly useful for cleaning at a relatively low temperature of less than about 120° C.