Substrate Support Plasma Cleaning Above 500°C Without Fluoride Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cleaning methods for semiconductor processing chambers are limited by temperature constraints, leading to contamination and process drifts due to fluoride sublimation and redeposition on cooler components, and the degradation of ceramic coatings on substrate supports, which increases cost of ownership and reduces device yield.
Innovation Solution
A high-temperature cleaning method using a plasma formed from a cleaning gas mixture including fluorine and oxygen, followed by a treatment plasma with a nitrogen-containing gas to remove oxygen radicals and maintain or restore the interface of the substrate support and bulk layer, allowing operation above 500°C without damaging the heater or chamber components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning methods are used with temperature limits below 500°C, then fluoride sublimation and redeposition on cooler components is avoided, but cleaning effectiveness is reduced and device yield decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the cleaning gas from conventional single-component gases to a multi-component mixture containing fluorocarbon gas (e.g., CF4, C2F6), oxygen gas, and nitrogen gas. This parameter change enables effective cleaning at temperatures above 500°C by modifying the plasma chemistry to reduce fluoride sublimation while maintaining cleaning effectiveness.
Solution Approach 2:
The patent applies a ceramic coating layer (such as aluminum oxide Al2O3, aluminum nitride AlN, or silicon oxide SiO2) on the substrate support surface. This composite structure combines the substrate support material with a protective ceramic coating that has high thermal stability and resistance to fluoride sublimation, allowing the system to operate at elevated temperatures without damage.
2Reliability
If high temperature cleaning above 500°C is implemented, then cleaning effectiveness and device yield improve, but fluoride sublimation occurs and condenses on cooler chamber components causing contamination
Solution Approach 1:
The patent introduces oxygen gas and nitrogen gas into the cleaning plasma to change the chemical environment. The oxygen reacts with fluoride species to form volatile compounds that can be pumped away, while nitrogen helps stabilize the plasma and reduce unwanted fluoride condensation on cooler surfaces.
Solution Approach 2:
The ceramic coating layer acts as an intermediary barrier between the substrate support and the cleaning plasma. It protects the underlying substrate support from direct exposure to high-energy plasma species while allowing effective cleaning to occur, and prevents fluoride sublimation that would otherwise contaminate chamber components.
3Reliability
If ceramic coatings are applied on substrate support, then resistance to cleaning gases is improved, but coatings wear off during substrate placement and removal
Solution Approach 1:
The patent optimizes the coating thickness parameter to a specific range (e.g., 1-10 micrometers) that provides sufficient protection during cleaning operations while maintaining flexibility to accommodate substrate thermal expansion and mechanical stresses during loading/unloading cycles.
Solution Approach 2:
The patent applies ceramic coating selectively on specific regions of the substrate support where exposure to cleaning plasma is most severe, while leaving other regions uncoated or with different coating properties to facilitate substrate handling and reduce wear during placement and removal operations.
4Productivity
If substrate support size and complexity are increased, then processing capability is improved, but coating maintenance time and cost increase
Solution Approach 1:
The patent divides the substrate support into modular sections or zones with different coating requirements. This segmentation allows for selective maintenance and repair of only the affected coating regions rather than requiring complete recoating of the entire complex structure, reducing maintenance time and cost.
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 cleans and maintains the substrate support and chamber components at high temperatures, reducing contamination, process drifts, and extending the lifetime of the heater and other components by preventing the formation of micro-voids and cracks, thus improving device yield and reducing cost of ownership.
Implementation Method 1
forming a plasma at a high temperature from a cleaning gas mixture
Implementation Method 2
The cleaning process includes forming a plasma at a high temperature, which may be the same as the film deposition temperature from a cleaning gas mixture
Implementation Method 3
removing oxygen radicals from the processing environment at the high temperature with a treatment plasma formed from a treatment gas mixture
Implementation Method 4
maintaining, repairing, or restoring an interface of the substrate support and the bulk layer at the high temperature with a pre-treatment or post-treatment plasma
Data Source
AI summary
Examples disclosed herein relate to a method and apparatus for cleaning and repairing a substrate support having a heater disposed therein. A method includes (a) cleaning a surface of a substrate support having a bulk layer, the substrate support is disposed in a processing environment configured to process substrates. The cleaning process includes forming a plasma at a high temperature from a cleaning gas mixture having a fluorine containing gas and oxygen. The method includes (b) removing oxygen radicals from the processing environment with a treatment plasma formed from a treatment gas mixture. The treatment gas mixture includes the fluorine containing gas. The method further includes (c) repairing an interface of the substrate support and the bulk layer with a post-treatment plasma. The post-treatment plasma is formed from a post-treatment gas mixture including a nitrogen containing gas. The high temperature is greater than or equal to about 500 degrees Celsius.