Pulsed Supercritical Fluid Injection for Deep Precursor Penetration
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Solution Overview
Problem
Conventional infiltration/impregnation methods for improving surface properties of porous materials are time-consuming and inefficient due to drifting, scattering, and limited penetration depth of precursor molecules, resulting in insufficient transformation into the substrate.
Innovation Solution
A method involving periodic injection of a mixture of a precursor and supercritical fluid (SCF) towards the substrate at atmospheric pressure lower than the critical pressure of the SCF, utilizing high-velocity waves to enhance penetration depth and react with substrate materials, potentially aided by a shaping fluid to confine and shape the waves, and optional plasma treatment to transform the precursor into a solid state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional injecting techniques are used in VPI processes, then precursor molecules can diffuse into substrates, but the hold step is time consuming and has low productivity
Solution Approach 1:
The patent employs periodic pulsing of precursor molecules toward the substrate surface, replacing the continuous hold step with rhythmic injection cycles. This periodic action maintains sufficient diffusion time while dramatically reducing total process duration, thereby resolving the contradiction between productivity and hold step time.
Solution Approach 2:
The patent changes the delivery parameters of precursor molecules by using pulsed injection with controlled frequency and duration. This parameter modification allows the process to achieve effective penetration without requiring extended hold times, thus improving productivity while minimizing time loss.
2Quantity of substance
If conventional injecting techniques are used, then precursor molecules can reach the substrate surface, but molecules drift and scatter resulting in limited number arriving at surface
Solution Approach 1:
By using periodic pulsing rather than continuous injection, the system creates concentrated bursts of precursor molecules that maintain higher local densities during travel to the substrate. This reduces drift and scattering effects, increasing the quantity of molecules that successfully reach and penetrate the substrate surface.
Solution Approach 2:
The pulsed injection method ensures continuous delivery of precursor molecules to the substrate through repeated cycles, maintaining a steady supply of reactive species. This continuous action compensates for any individual pulse losses and ensures sufficient quantity arrives at the surface for effective treatment.
3Length of stationary object
If conventional injecting techniques are used, then precursor molecules can adsorb on substrate surface, but they lack sufficient energy to penetrate into porous material with desired depth
Solution Approach 1:
The periodic pulsing delivers precursor molecules in concentrated bursts with higher instantaneous velocity and kinetic energy. This energy concentration enables molecules to overcome diffusion barriers and penetrate deeper into the porous substrate structure, achieving the desired penetration depth that conventional continuous injection cannot accomplish.
Solution Approach 2:
The patent modifies the energy parameters of precursor delivery by controlling pulse frequency, duration, and pressure. These parameter changes increase the kinetic energy of incoming molecules, enabling them to penetrate deeper into the substrate while maintaining control over the treatment process.
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 approach significantly increases the penetration depth and efficiency of precursor molecules into the substrate, enhancing surface properties such as physical, electrical, and mechanical properties, while reducing the need for hold steps and improving productivity.
Implementation Method 1
As the mixture propagates toward the substrate, the SCF converts to a gas phase and expands, causing a high velocity of the waves towards the substrate
Implementation Method 2
molecules of the precursor can diffuse into a porous material to improve properties of the porous material
Implementation Method 3
The plasma radicals can react with the molecules of the precursor that penetrate into the substrate to transform the molecules of the precursor into a solid state
Data Source
AI summary
An injecting assembly includes a nozzle that is formed with a mixture channel, a mixture opening communicating with the mixture channel, a shaper channel, and a shaper opening communicating with the shaper channel. A mixture of a precursor and a supercritical fluid (SCF) passes through the mixture channel. Waves of the mixture are periodically injected toward a surface of a substrate at the mixture opening. A stream of a shaping fluid flows through the shaper channel and is injected toward the substrate at the shaper opening. The stream of the shaping fluid confines the waves of the mixture. Molecules of the precursor penetrate into the substrate by impact of the wave fronts reaching the surface of the substrate. The molecules of the precursor can react with molecules of a material of the substrate to improve surface properties of the substrate.