Isolator Ring Structure to Limit Gas Diffusion Below the Pedestal
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Solution Overview
Problem
During substrate processing operations, processing gases diffuse below the top surface of a pedestal, leading to material deposition on outer surfaces of the substrate processing chamber, causing delays, increased cleaning time, reduced throughput, and substrate defects.
Innovation Solution
A substrate processing chamber design incorporating a showerhead with gas openings, a pedestal, a pumping liner, and an isolator ring with a protrusion that defines a necked portion between the pedestal and the isolator ring, along with a controlled flow of purge gases to prevent gas diffusion, utilizing a ratio of purge gas flow rate relative to processing gas flow rate within a range of 0.25 to 0.75.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If processing gases are flowed during substrate processing operations, then substrate processing can be performed, but processing gases diffuse below the top surface of the pedestal causing material deposition on outer surfaces of the chamber
Solution Approach 1:
An isolator ring is introduced as an intermediary component between the pedestal and the chamber wall. This isolator ring creates a physical barrier that prevents processing gases from diffusing below the pedestal top surface, thereby eliminating material deposition on chamber surfaces while allowing substrate processing to continue normally
Solution Approach 2:
The isolator ring segments the chamber into distinct regions: a processing region above the pedestal where substrate processing occurs, and a isolated region below the pedestal top surface where gas diffusion is prevented. This segmentation contains the processing gases to the intended processing zone
2Productivity
If processing gases diffuse below the pedestal top surface, then substrate processing can proceed, but cleaning time increases and operational delays occur
Solution Approach 1:
The isolator ring serves as a preventive intermediary that stops processing gases from reaching areas that would require cleaning. By blocking gas diffusion at the source, the isolator ring prevents material deposition on surfaces that would otherwise need periodic cleaning, thereby reducing cleaning time and operational delays
Solution Approach 2:
The isolator ring is installed in advance to prevent gas diffusion before it can cause material deposition. This preliminary protective action eliminates the need for subsequent cleaning operations, saving time and maintaining continuous productivity
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 design effectively reduces gas diffusion below the pedestal, minimizing deposition on surfaces other than the substrate, thereby reducing operational delays, cleaning time, and substrate defects, while maintaining high throughput and reducing operational costs.
Implementation Method 1
processing gases may diffuse below a top surface of a pedestal
Implementation Method 2
flow one or more processing gases at a first flow rate from a showerhead above a pedestal and into a processing region
Data Source
AI summary
Aspects of the present disclosure relate generally to isolator devices, components thereof, and methods associated therewith for substrate processing chambers. In one implementation, a substrate processing chamber includes an isolator ring disposed between a pedestal and a pumping liner. The isolator ring includes a first surface that faces the pedestal, the first surface being disposed at a gap from an outer circumferential surface of the pedestal. The isolator ring also includes a second surface that faces the pumping liner and a protrusion that protrudes from the first surface of the isolator ring and towards the outer circumferential surface of the pedestal. The protrusion defines a necked portion of the gap between the pedestal and the isolator ring.