Focus Ring Quartz Gap Insert for In-Situ Deposit Suppression
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Solution Overview
Problem
In substrate processing apparatuses, deposits tend to adhere to members with lower temperatures in gaps between focus rings and susceptors, causing operational inefficiencies due to the difficulty in removing these deposits without opening the chamber to the atmosphere.
Innovation Solution
Incorporating a quartz member in the gaps between the inner and outer focus rings and between the focus rings and the susceptor, which generates oxygen radicals when exposed to plasma, decomposing and removing deposits, and using a gas supply unit to push out reaction products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the inner focus ring is cooled to control wafer temperature distribution, then uniform plasma process is achieved, but deposits adhere to the inner focus ring in the gap between inner and outer focus rings
Solution Approach 1:
A non-reactive member (quartz or ceramic) is placed in the gap between the inner and outer focus rings to serve as an intermediary surface. This intermediary member prevents reaction products from directly adhering to the cooled inner focus ring, while its non-reactive nature prevents deposit formation. The intermediary member effectively decouples the temperature control function from the deposit adhesion problem.
2Object-generated harmful factors
If the chamber is opened to the atmosphere to remove deposits from the inner focus ring, then deposits are removed, but the operation rate of the substrate processing apparatus is deteriorated
Solution Approach 1:
The non-reactive member in the gap between focus rings serves a dual function: it prevents deposit adhesion during processing and facilitates deposit removal by providing a surface that can be cleaned in-situ. The member's material properties enable it to resist deposit adhesion while allowing plasma or cleaning gases to access and remove any accumulated deposits without requiring chamber opening.
3Temperature
If the susceptor is cooled to a temperature lower than the inner focus ring, then wafer temperature control is improved, but deposits adhere to the susceptor in the gap between the inner focus ring and the susceptor
Solution Approach 1:
A non-reactive member is positioned between the inner focus ring and the susceptor to act as an intermediary barrier. This member prevents reaction products from adhering to the cooled susceptor surface while allowing thermal energy to pass through. The intermediary member's position and material properties enable it to block deposit formation pathways while maintaining the temperature gradient necessary for process control.
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, maintaining operational efficiency by allowing for in-situ removal of deposits without opening the chamber, thus improving the overall operation rate of the substrate processing apparatus.
Implementation Method 1
a quartz member placed in a gap between the inner focus ring and the outer focus ring... which generates oxygen radicals when exposed to plasma
Implementation Method 2
generates oxygen radicals when exposed to plasma, decomposing and removing deposits
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.