Plasma Processing Baffle Structure for Pressure Uniformity
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Solution Overview
Problem
In plasma processing apparatuses, uneven gas flow due to non-central exhaust connections leads to deteriorated in-plane uniformity of plasma processing, affecting the distribution of pressure on the workpiece.
Innovation Solution
A baffle structure with a cylindrical portion and adjustable second members is introduced between the placement table and the processing container, allowing for adjustment of conductance between spaces to optimize pressure distribution by moving or inclining the second members, thereby controlling the shielding of through holes and radial distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the exhaust apparatus is connected to the exhaust path at a position deviated from the center of the placement table, then the exhaust path can be formed between the side wall and placement table, but the conductance becomes non-uniform in the circumferential direction, causing uneven gas flow and deteriorated in-plane uniformity of plasma processing
Solution Approach 1:
A baffle structure is introduced as an intermediary component between the exhaust path and the placement table. This baffle structure includes a cylindrical portion with through holes and adjustable second members that can be positioned to control gas flow distribution. The baffle acts as a mediator to redistribute the gas flow from the non-uniform exhaust connection, creating more uniform pressure distribution across the placement table surface without requiring repositioning of the exhaust apparatus itself.
Solution Approach 2:
The baffle structure incorporates movable second members that can be adjusted in position and orientation. These second members can be moved radially outward to form a cylindrical body with larger inner diameter, or individually positioned to control the shielding of through holes in the cylindrical portion. This dynamic adjustability allows optimization of gas flow distribution to achieve uniform pressure across the placement table while maintaining the fixed exhaust connection configuration.
2Manufacturing precision
If a baffle structure with adjustable second members is introduced to control pressure distribution, then in-plane uniformity of plasma processing is improved, but the device complexity increases
Solution Approach 1:
The baffle structure is segmented into distinct functional components: a cylindrical portion with through holes for gas flow, and multiple separate second members that can be independently adjusted. This segmentation allows each component to perform its specific function - the cylindrical portion provides the basic flow distribution, while the individual second members can be positioned to control shielding of specific through holes. This modular segmentation simplifies the adjustment process compared to a fully integrated complex structure.
Solution Approach 2:
The second members of the baffle structure can be individually positioned and oriented to control the shielding of specific through holes in the cylindrical portion. This local adjustment capability allows precise control of gas flow distribution in different circumferential regions. Rather than requiring uniform adjustment across the entire structure, only specific local regions can be modified to achieve the desired pressure distribution pattern across the placement table.
Data Source
AI summary
A plasma processing apparatus includes a processing container; a placement table provided in the processing container and including a placement region on which a workpiece is placed for a plasma processing; a baffle structure that defines a first space and a second space, and including a first member and at least one second member; a gas supply portion connected to the first space; a first pressure gauge connected to the first space; an exhaust apparatus connected to the second space; a second pressure gauge connected to the second space; a driving mechanism that moves the at least one second member in a vertical direction; a displacement gauge configured to measure a position or a distance of the second member; and a controller that controls the driving mechanism. The controller controls the driving mechanism such that a pressure of the first space becomes a predetermined pressure designated by a recipe.