Non-sealing Throttle Valve Projections for ALD Debris Management
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Solution Overview
Problem
Throttle valves in substrate processing systems, used for ALD and CVD, face premature failure due to wear and leakage caused by process byproducts, leading to reduced throughput and tool availability.
Innovation Solution
A throttle valve design featuring projections with a triangular cross-section on the throttle plate that extend around the circumference, interacting with mating stop surfaces on the housing, enhances surface contact pressure to cut through debris and maintain low conductance, extending the service cycle and improving tool availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate valves or sealing valves are used to deliver and purge precursors, then valve sealing performance is improved, but valve service life deteriorates due to high cycle count and seal wear
Solution Approach 1:
The patent removes the seal component entirely from the valve design, transitioning from a sealing valve to a non-sealing throttle valve. This extraction of the seal eliminates the wear mechanism that limited service life, while the throttle plate geometry and projection-stop surface interaction maintain sufficient sealing performance for ALD applications.
Solution Approach 2:
The patent employs a simple metal-on-metal throttle plate design without expensive polymer seals. While the valve body may require periodic maintenance, the throttle mechanism itself becomes a durable, wear-resistant component that can withstand high cycle counts typical of ALD processes.
2Duration of action of stationary object
If low-conductance non-sealing throttle valves with flat metal-on-metal surfaces are used, then valve service life is improved, but leakage increases over time due to process byproduct buildup
Solution Approach 1:
The patent applies local quality by adding projections to specific locations on the throttle plate perimeter and corresponding stop surfaces on the valve body. These localized features concentrate contact pressure at discrete points, enabling the valve to cut through process debris and maintain low leakage without requiring the entire surface to be highly conductive or perfectly clean.
Solution Approach 2:
The projections and stop surfaces are designed to actively cut through and remove process byproduct buildup before it can create significant leakage paths. This preliminary mechanical cleaning action prevents the progressive degradation seen in flat-surface throttle valves.
3Productivity
If throttle valves are used to meet high cycle requirements, then throughput is improved, but tool availability deteriorates due to frequent valve failures and maintenance
Solution Approach 1:
By removing the seal component, the patent eliminates the primary failure mode in high-cycle valve operation. The sealless design allows the valve to withstand the high cycle counts required for high-throughput ALD production without the periodic failures that plague sealed valve designs.
Solution Approach 2:
The patent changes the fundamental operating parameter from sealed contact to controlled metal-on-metal throttling with projection-stop surface interaction. This parameter change enables the valve to operate reliably under the high-cycle, high-temperature, and chemically aggressive conditions typical of semiconductor manufacturing.
Data Source
AI summary
A throttle valve includes a throttle body including a housing having an inner surface. The throttle body includes first and second stop surfaces arranged on the inner surface. A throttle plate is rotatable inside the housing of the throttle body about a shaft between closed and open positions. A first projection is located on a first surface of the throttle plate adjacent to a radially outer end of the throttle plate. A second projection is located on a second surface of the throttle plate adjacent to a radially outer end of the throttle plate. The second surface is opposite the first surface. The first and second projections extend outwardly from the throttle plate in opposite directions and in corresponding directions of rotational movement of the throttle plate during closing to bias against the second stop surface when the throttle valve is closed.