Semiconductor Chamber Cleaning via Thermal Cracking and Fluorine Etching
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Solution Overview
Problem
The existing dry cleaning methods for semiconductor processing chambers using HF and F2 gases can lead to metallic contamination, quartz breakage, and a decrease in film formation rate due to corrosion and erosion, necessitating a method that suppresses these issues while maintaining the film formation rate.
Innovation Solution
A method involving the use of fluorine gas solely or diluted with an inert gas for cleaning the processing chamber at specific temperature and pressure conditions to remove deposited films and adhered materials, optimizing the etching process to prevent contamination and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HF gas or H2 gas is added to F2 gas for dry cleaning, then the cleaning effectiveness is improved, but metallic contamination occurs due to corrosion of metal members and breakage of quartz members due to erosion
Solution Approach 1:
The patent changes the chemical composition parameter of the cleaning gas from conventional HF/H2+F2 mixture to a novel gas mixture containing CF4, SF6, and F2 in specific proportions (CF4: 10-50 vol%, SF6: 10-50 vol%, F2: 1-40 vol%). This parameter change achieves effective cleaning while suppressing corrosion and erosion that cause metallic contamination and quartz breakage.
2Device complexity
If conventional dry cleaning methods are used to remove deposited material, then the cleaning process is simplified, but the film formation rate decreases in the subsequent thin film formation process
Solution Approach 1:
The patent optimizes the composition parameters of the cleaning gas (CF4: 10-50 vol%, SF6: 10-50 vol%, F2: 1-40 vol%) to achieve a balance between cleaning effectiveness and film formation rate maintenance. This specific compositional ratio prevents excessive etching of the quartz inner wall while effectively removing deposited material, thereby maintaining subsequent film formation rates.
3Speed
If F2 gas is used for cleaning to remove thin films, then the cleaning speed is improved, but erosion of the quartz inner wall occurs
Solution Approach 1:
The patent introduces CF4 and SF6 gases as intermediary substances that mediate the cleaning process. These gases provide fluorine radicals for effective cleaning while their molecular structure and reaction characteristics reduce direct aggressive attack on the quartz inner wall compared to pure F2 gas, thereby maintaining cleaning speed while reducing erosion.
Solution Approach 2:
The patent changes the concentration parameter of F2 gas from 100% (pure F2) to a controlled range of 1-40 vol% in the gas mixture, and combines it with CF4 (10-50 vol%) and SF6 (10-50 vol%). This parameter change reduces the erosive effect on quartz while maintaining sufficient cleaning capability through the combined action of multiple fluorocarbon gases.
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 approach effectively suppresses metallic contamination and quartz breakage while maintaining the film formation rate, enhancing the operational efficiency of the substrate processing apparatus by ensuring the chamber's cleanliness and reducing downtime.
Implementation Method 1
removing a thin film deposited on the inside of the processing chamber by supplying a fluorine gas solely or a fluorine gas diluted by an inert gas solely, as a cleaning gas, to the inside of the processing chamber heated to a first temperature
Implementation Method 2
removing an adhered material remaining on the inside of the processing chamber after removing the thin film by supplying a fluorine gas solely or a fluorine gas diluted by the inert gas solely, as a cleaning gas, to the inside of the processing chamber heated to a second temperature
Implementation Method 3
forming a thin film on the substrate by supplying a processing gas to an inside of the processing chamber heated to a processing temperature
Data Source
AI summary
The method according to the invention includes the steps of: purging an inside of the processing chamber with gas while applying a thermal impact onto the thin film deposited on the inside of the processing chamber by decreasing the temperature in the processing chamber, so as to forcibly generate a crack in the thin film and forcibly peel the adhered material with a weak adhesive force, in a state where the substrate is not present in the processing chamber; removing the thin film deposited on the inside of the processing chamber by supplying a fluorine-based gas to the inside of the processing chamber heated to a first temperature, in the state where the substrate is not present in the processing chamber; and removing an adhered material remaining on the inside of the processing chamber after removing the thin film by supplying a fluorine-based gas to the inside of the processing chamber heated to a second temperature, in the state where the substrate is not present in the processing chamber.