Focus Ring Gap Structure to Prevent Plasma Deposit Adhesion
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Solution Overview
Problem
Deposits tend to adhere to members with lower temperatures in gaps between focus rings and susceptor in substrate processing apparatuses, leading to reduced operation efficiency due to the need to open the chamber and remove the focus rings for cleaning.
Innovation Solution
Incorporation of a quartz member in the gaps between the inner and outer focus rings and the susceptor to generate oxygen radicals that decompose deposits, along with gas supply to push out reaction products and a thin-plate shaped flange to reduce temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the inner focus ring is cooled to control wafer temperature uniformity, then the temperature distribution of the wafer is improved, but deposits adhere to the inner focus ring in the gap between the inner and outer focus rings
Solution Approach 1:
A quartz member is introduced as an intermediary component placed in the gap between the inner focus ring and outer focus ring. This quartz member serves as a mediator that prevents deposits from adhering to the inner focus ring while allowing the cooling function to continue. The quartz member may be subjected to plasma treatment to generate oxygen radicals that decompose deposits, thus protecting the inner focus ring from contamination.
Solution Approach 2:
The cooling of the inner focus ring, which originally causes temperature uniformity improvement, is converted into a beneficial feature while its harmful side effect (deposit adhesion) is eliminated. By introducing the quartz member that can generate oxygen radicals through plasma treatment, the cold surface that attracts deposits is transformed into a surface that actively decomposes deposits, converting the harmful temperature difference into a beneficial cleaning mechanism.
2Object-generated harmful factors
If the chamber is opened to remove deposits from the inner focus ring, then the deposits are removed, but the operation rate of the substrate processing apparatus is deteriorated
Solution Approach 1:
The quartz member placed in the gap between the focus rings enables self-cleaning functionality. During plasma processing, the quartz member generates oxygen radicals that automatically decompose and remove deposits from the inner focus ring without requiring chamber opening or manual intervention. This self-service mechanism maintains continuous operation and preserves high productivity.
Solution Approach 2:
The deposit removal process is made continuous rather than periodic. The quartz member continuously generates oxygen radicals during plasma processing, providing ongoing deposit decomposition and removal. This eliminates the need to stop operations for cleaning, maintaining continuous useful action and high operation rate.
3Temperature
If the susceptor is cooled to a lower temperature than the inner focus ring, then the inner focus ring temperature is controlled, but deposits adhere to the susceptor in the gap between the inner focus ring and susceptor
Solution Approach 1:
A quartz member is introduced as an intermediary component placed in the gap between the inner focus ring and susceptor. This quartz member prevents deposits from adhering to the susceptor by generating oxygen radicals through plasma treatment. The intermediary quartz member protects both the susceptor and inner focus ring from deposit adhesion while allowing the temperature control function to continue.
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
Prevents deposits from adhering to the inner focus ring and susceptor by using quartz to generate oxygen radicals and manage temperature differences, maintaining apparatus efficiency without chamber opening.
Implementation Method 1
a quartz member placed in a gap between the inner focus ring and the outer focus ring
Implementation Method 2
Incorporation of a quartz member in the gaps between the inner and outer focus rings and the susceptor to generate oxygen radicals that decompose deposits
Implementation Method 3
an inner focus ring (hereinafter, referred to as an "inner focus ring") is provided and a second focus ring (hereinafter, referred to as an "outer focus ring") is placed at an outside of the first focus ring, and the first focus ring is cooled
Implementation Method 4
along with gas supply to push out reaction products
Data Source
AI summary
There is provided a focus ring that is capable of preventing deposits from adhering to a member having a lower temperature in a gap between two members having different temperatures. A focus ring 25 is disposed to surround a peripheral portion of a wafer W in a chamber 11 of a substrate processing apparatus 10. The focus ring 25 includes an inner focus ring 25a and an outer focus ring 25b. Here, the inner focus ring 25a is placed adjacent to the wafer W and configured to be cooled; and the outer focus ring 25b is placed so as to surround the inner focus ring 25a and configured not to be cooled. Further, a block member 25c is provided in a gap between the inner focus ring 25a and the outer focus ring 25b.