ALD Pulsing Valve With Continuous Purge to Prevent Particle Formation
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Solution Overview
Problem
Conventional atomic layer deposition (ALD) reactors face challenges in preventing precursor gas mixing, leading to particle formation and substrate damage, due to long purge times and potential trapping of precursor chemicals in valve cavities, which hinder high pulsing speed and chemical stability.
Innovation Solution
An apparatus with a pulsing valve featuring a closure and an additional cleaning chemical inlet to purge the valve output surface, ensuring continuous cleaning and preventing precursor chemical trapping, allowing for high pulsing speed and minimizing particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 4-way valve with vertical cavity is used for continuous purge gas flow, then continuous purging is achieved, but precursor chemicals are trapped in the cavity and cause particle formation on substrate
Solution Approach 1:
The patent extracts the harmful vertical cavity from the valve design by using a flat membrane closure that eliminates the cavity space where precursor chemicals could be trapped. The membrane provides a flat sealing surface that prevents chemical accumulation while maintaining the continuous purging function.
Solution Approach 2:
The patent introduces a flat membrane as an intermediary closure element that separates the purge gas flow path from the reaction chamber without creating trapped spaces. The membrane acts as a mediator that allows continuous purging while preventing precursor chemical trapping that would occur with traditional valve designs.
2Reliability
If long purge times are used to prevent gas mixing, then precursor chemical mixing is prevented, but process time increases and precursor chemicals decompose
Solution Approach 1:
The patent implements continuous purging action through the flat membrane valve design that allows uninterrupted purge gas flow. This continuous action maintains precise gas separation without requiring extended purge times, enabling faster cycling while preventing precursor mixing and decomposition.
Solution Approach 2:
The patent uses rapid periodic pulsing of precursor gases separated by continuous purge cycles. The flat membrane valve enables this periodic action by quickly switching between precursor delivery and purging phases, maintaining gas separation while reducing overall process time and preventing chemical decomposition.
3Productivity
If high pulsing speed is implemented, then productivity increases, but precursor chemicals may be trapped in valve cavity causing particle formation
Solution Approach 1:
The patent removes the vertical cavity from the valve design to eliminate the source of precursor chemical trapping. This extraction enables high pulsing speeds without the risk of chemicals being trapped and later released as particles on the substrate.
Solution Approach 2:
The flat membrane valve design performs preliminary purging action before each precursor pulse, ensuring no chemicals are trapped in the valve structure. This preliminary action prevents particle formation while enabling rapid pulsing cycles for high 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
The solution effectively prevents precursor chemical trapping and particle formation, enabling high-speed pulsing operations while maintaining substrate quality by continuously purging the valve output surface with a cleaning chemical, thus enhancing the efficiency and reliability of ALD processes.
Implementation Method 1
an additional cleaning chemical inlet at the reaction chamber side of the closure to purge the closure
Implementation Method 2
a closure having an open and closed configuration to open and close, respectively, a route from the reactive chemical inlet to the reaction chamber outlet
Data Source
AI summary
An apparatus, a method and a valve with a reactive chemical inlet, a reaction chamber outlet, and a closure having an open and closed configuration to open and close, respectively, a route from the reactive chemical inlet to the reaction chamber outlet, the valve further including an additional cleaning chemical inlet at a downstream side of the closure to purge the closure.