Electrostatic Chuck Fluorine Removal via Hydrogen Plasma
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Solution Overview
Problem
Contaminants on the surface of electrostatic chucks, particularly fluorine residues, lead to inadequate de-chucking of substrates, resulting in substrate breaks and reduced operational lifetimes of the chuck, as existing methods like physical cleaning and nitrogen-based plasma treatments are inefficient in removing trapped charges and fluorine.
Innovation Solution
Exposing the chuck to a hydrogen-containing plasma, such as a hydrocarbon-based plasma, when no substrate is present, to react with and remove contaminants like fluorine, followed by an additional plasma ash step to remove any newly formed deposits, thereby improving substrate de-chucking and reducing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical cleaning and nitrogen-based plasma treatment are used to remove contaminants from the chuck surface, then some contamination removal is achieved, but fluorine residues and trapped charges remain, leading to insufficient de-chucking
Solution Approach 1:
The patent changes the chemical composition parameter of the plasma from nitrogen-based to hydrogen-containing plasma. This parameter change enables the plasma to effectively remove fluorine contaminants through chemical reactions (hydrogen-fluorine reactions), thereby resolving the insufficient de-chucking problem caused by trapped charges and fluorine residues
Solution Approach 2:
The patent converts the harmful effect of hydrogen-containing plasma (which can cause deposits) into a beneficial effect by first using it to remove fluorine contaminants and trapped charges, then followed by an oxygen plasma ashing step to remove any hydrogen-based deposits. This two-step process transforms potential harm into benefit
2Loss of substance
If hydrogen-containing plasma is used to remove fluorine contaminants, then contaminant removal efficiency improves, but hydrogen-based deposits may form on the chuck surface
Solution Approach 1:
The patent implements a continuous two-step plasma process: first hydrogen-containing plasma removes fluorine contaminants, then oxygen plasma immediately follows to remove hydrogen-based deposits. This continuous action ensures the chuck surface is cleaned of both fluorine residues and hydrogen deposits without interruption
Solution Approach 2:
The oxygen plasma acts as an intermediary step between the hydrogen-containing plasma and the final clean surface. It mediates by converting hydrogen-based deposits into volatile species that can be removed, thereby eliminating the harmful effect of hydrogen deposits
3Loss of substance
If the chuck is frequently removed for physical cleaning and resurfacing, then contaminant removal is achieved, but tool downtime increases and operational lifetime is reduced
Solution Approach 1:
The patent replaces mechanical cleaning and resurfacing methods with a chemical plasma-based cleaning method. The hydrogen-containing plasma chemically reacts with fluorine contaminants to remove them, eliminating the need for physical intervention and associated tool downtime
Solution Approach 2:
The plasma cleaning process can be performed in-situ within the processing tool without removing the chuck. The chuck effectively cleans itself through the plasma treatment, eliminating the need for external cleaning operations and extending operational lifetime
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 method effectively reduces substrate breakage by removing contaminants from the chuck surface, enhancing de-chucking efficiency and extending the operational life of the electrostatic chuck.
Implementation Method 1
exposing the surface of the chuck to a plasma process that comprises a hydrogen (H)-containing plasma
Implementation Method 2
Hydrogen in the hydrocarbon plasma may react with and remove the contaminants
Implementation Method 3
the trapped charges in the fluorinated chuck surface may be removed by exposing the chuck surface to a nitrogen-based plasma
Implementation Method 4
a subsequent plasma ash step
Data Source
AI summary
Embodiments are disclosed for reducing substrate breaks which result from inadequate de-chucking. Contaminants are removed from the surface of a chuck by exposing the chuck to a plasma process that comprises a hydrogen (H)-containing plasma. The chuck is subjected to the hydrogen-based plasma when no substrate is on the chuck. In one embodiment, the plasma is a hydrocarbon-based plasma. Hydrogen in the hydrocarbon plasma may react with and remove the contaminants. The process may further include an additional plasma step for removal of any newly formed materials that may result from the hydrocarbon plasma. The removal step may be, for example, a subsequent plasma ash step. In one embodiment, the chuck is an electrostatic chuck and the contaminants comprise fluorine. By removing contaminants from the chuck surface, improved substrate de-chucking occurs. This improvement correspondingly leads to less substrate breakage when removing substrates from the chuck.