Plasma Chamber Cleaning Using a Dummy Substrate for Chuck Periphery
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Solution Overview
Problem
Existing cleaning methods for plasma processing apparatuses are inefficient in removing deposits from the periphery of the electrostatic chuck, leading to incomplete cleaning and potential damage during etching processes.
Innovation Solution
A dual cleaning operation method is introduced, where a first plasma is generated using an oxygen-containing gas to clean the placement region, and a second plasma, with higher energy density, is generated using a fluorine-containing gas while holding a dummy substrate at a predetermined distance to effectively clean the periphery of the placement region, along with a modification operation using nitrogen plasma to nitride the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single plasma cleaning operation is used, then the cleaning process is simple, but the cleaning completeness is insufficient especially in the periphery region
Solution Approach 1:
The cleaning process is divided into two distinct operations: a first cleaning operation that cleans the placement region, and a second cleaning operation that cleans the periphery region. This segmentation allows each operation to be optimized for its specific target area, improving overall cleaning completeness while maintaining manageable process complexity.
Solution Approach 2:
Different cleaning conditions are applied to different regions: the first cleaning operation uses specific plasma conditions for the placement region, while the second cleaning operation uses different plasma conditions (including a dummy substrate) for the periphery region. This local quality approach ensures optimal cleaning for each specific area's requirements.
2Manufacturing precision
If cleaning is performed without a dummy substrate, then the process is simpler, but deposits in the periphery region cannot be effectively removed
Solution Approach 1:
A dummy substrate is introduced as an intermediary object in the second cleaning operation. This dummy substrate serves as a mediator to generate plasma that effectively reaches and cleans the periphery region of the electrostatic chuck, which would be difficult to access without this intermediate element.
Solution Approach 2:
The dummy substrate is positioned in advance at a predetermined location before the second cleaning operation begins. This preliminary positioning ensures that the plasma generated during cleaning will effectively cover the periphery region, preparing the system for optimal cleaning performance before the actual cleaning process starts.
3Manufacturing precision
If longer cleaning time is used, then cleaning completeness improves, but maintenance time increases reducing productivity
Solution Approach 1:
The cleaning process is segmented into two targeted operations, each optimized for specific regions. This segmentation allows the total cleaning time to be reduced compared to a single prolonged cleaning operation, because each segment focuses its energy on a specific area, achieving complete cleaning more efficiently.
Solution Approach 2:
Different plasma parameters are used in the two cleaning operations to optimize cleaning efficiency for each region. By changing parameters such as gas flow rates, power levels, and substrate positioning, the cleaning process achieves high completeness in reduced time, improving overall 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 method ensures thorough cleaning of both the placement and peripheral regions, reducing maintenance time and improving etching throughput by efficiently removing deposits and protecting the electrostatic chuck surface.
Implementation Method 1
cleaning a region including the placement region of the stage by generating a first plasma from the first processing gas in a space defined by the placement region and the electrode
Implementation Method 2
supplying a first processing gas to an interior of the chamber, and cleaning a region including the placement region of the stage by generating a first plasma from the first processing gas
Implementation Method 3
cleaning a region including a periphery of the placement region of the stage by generating a second plasma from the second processing gas in a space defined by the dummy substrate held at the predetermined position and the electrode
Implementation Method 4
supplying a second processing gas to the interior of the chamber, and cleaning a region including a periphery of the placement region of the stage by generating a second plasma from the second processing gas
Implementation Method 5
a modification operation using nitrogen plasma to nitride the surface
Data Source
AI summary
A cleaning method according to the present disclosure includes a first cleaning operation and a second cleaning operation, wherein the first cleaning operation includes: supplying a first processing gas to the interior of the chamber; and cleaning a region including the placement region of the stage by generating a first plasma from the first processing gas in a space defined by the placement region and the electrode, and the second cleaning operation includes: holding a dummy substrate at a predetermined position spaced by a predetermined distance from the placement region to face the placement region; supplying a second processing gas to the interior of the chamber; and cleaning a region including a periphery of the placement region of the stage by generating a second plasma from the second processing gas in a space defined by the dummy substrate held at the predetermined position and the electrode.