Bypass Choke Ring Gas Flow Conductance Control
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Solution Overview
Problem
Plasma processing chambers face challenges in achieving precise control of gas flow conductance, particularly in capacitively-coupled RF plasma reactors, where the existing gap control mechanisms often fail to provide the necessary range of flow conductance levels required for advanced microelectronics processing, leading to limitations in substrate processing.
Innovation Solution
The introduction of a mechanism that controls gas flow conductance through adjustable slots and rings, allowing for variable gas flow paths by rotating or moving bypass choke rings relative to stationary ground and cover rings, creating additional conductance paths and blocking mechanisms to achieve a wide range of flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing gap control mechanisms are used in capacitively-coupled RF plasma reactors, then the device structure remains simple, but the gas flow conductance range is insufficient for advanced microelectronics processing
Solution Approach 1:
The gas flow control system is segmented into multiple independent components: a ground ring with first set of slots, a cover ring with second set of slots, and a bypass choke ring with third set of slots. Each ring can be independently positioned to control gas flow through its respective slots, providing fine-grained control over the overall gas flow conductance range without requiring complete redesign of the entire system.
Solution Approach 2:
The invention adds a new dimensional control mechanism by introducing the bypass choke ring that rotates about the central axis of the plasma processing chamber. This rotational degree of freedom provides an additional dimension for controlling gas flow conductance, allowing independent adjustment of flow rates through different slot sets (first, second, and third sets) to achieve a wide range of conductance levels.
2Adaptability or versatility
If the gas flow conductance range is expanded using multiple rings and slots, then plasma processing flexibility improves, but the device complexity increases
Solution Approach 1:
Each ring structure (ground ring, cover ring, bypass choke ring) serves multiple functions: they provide mechanical support, define gas flow paths through their slots, and can be independently positioned to control conductance. The overlapping slot configurations allow the same physical structure to control flow through multiple pathways simultaneously, reducing the need for additional separate control mechanisms.
Solution Approach 2:
The bypass choke ring is positioned within the space defined by the ground ring and cover ring, creating a nested configuration. The third set of slots in the bypass choke ring overlaps with the first and second sets of slots, allowing the inner ring to modulate flow through the outer rings' slot pathways. This nested arrangement maximizes control capability within a compact structural footprint.
3Manufacturing precision
If precise control of plasma parameters is required for smaller features and larger substrate sizes, then processing quality improves, but the control mechanism becomes more complex
Solution Approach 1:
The slot configurations in each ring are designed with specific local characteristics: the first set of slots in the ground ring, the second set in the cover ring, and the third set in the bypass choke ring have different orientations, positions, and dimensions. This local differentiation allows each region to control specific aspects of gas flow distribution across the substrate, enabling precise control of plasma parameters in different zones to accommodate smaller features and larger substrate sizes.
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 solution enables precise control of plasma conditions by expanding the gas flow conductance range, allowing for improved plasma processing capabilities and increased flexibility in handling diverse substrate processing requirements without the need for substrate unloading, thereby enhancing the efficiency and yield of microelectronics fabrication.
Implementation Method 1
a mechanism adapted to move the bypass choke ring relative to the ground ring to control gas flow conductance through the first and second sets of slots between (i) an ON state in which the first set of slots is in fluid communication with the second set of slots such that gas can flow through the first and second sets of slots and (ii) an OFF state in which the first set of slots is blocked by the bypass choke ring such that gas cannot flow through the first and second sets of slots
Implementation Method 2
a mechanism adapted to rotate the bypass choke ring relative to the ground ring to vary an amount of overlap between the first and third sets of slots to thereby control gas flow conductance through the first, second, and third sets of slots
Implementation Method 3
a mechanism adapted to move the choke ring relative to the ground ring to adjust the spacing to vary gas flow conductance through the first and second sets of slots between (i) an ON state in which the first set of slots is in fluid communication with the second set of slots such that gas can flow through the first and second sets of slots and (ii) an OFF state in which the first set of slots is blocked by the bypass choke ring such that gas cannot flow through the first and second sets of slots
Data Source
AI summary
Apparatuses are provided for controlling flow conductance of plasma formed in a plasma processing apparatus that includes an upper electrode opposite a lower electrode to form a gap therebetween. The lower electrode is adapted to support a substrate and coupled to a RF power supply. Process gas injected into the gap is excited into the plasma state during operation. The apparatus includes a ground ring that concentrically surrounds the lower electrode and has a set of slots formed therein, and a mechanism for controlling gas flow through the slots.