Plasma Baffle Design for Conformal PE-ALD Deposition
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Solution Overview
Problem
Conventional vapor deposition techniques, such as chemical vapor deposition (CVD) and thermal atomic layer deposition (ALD), face limitations in achieving conformal deposition on substrates with aggressive geometries and high aspect ratios, particularly due to slow deposition rates and compatibility issues with certain chemical precursors.
Innovation Solution
The development of a plasma-enhanced atomic layer deposition (PE-ALD) process and apparatus, featuring a process chamber with electrically insulated components and a specific configuration of a showerhead, plasma baffle, and plasma screen, which allows for the sequential exposure of substrates to gases and plasmas, enhancing deposition rates and compatibility with a wider range of precursors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal ALD process is used to deposit materials, then deposition conformality is achieved, but deposition rate is slow
Solution Approach 1:
The patent transitions from thermal ALD to plasma-enhanced ALD, changing the fundamental process parameter from thermal activation to plasma activation. This enables deposition at lower temperatures with higher rates while maintaining conformality, resolving the contradiction between slow deposition rate and deposition quality
Solution Approach 2:
The patent replaces the thermal field (heat-driven chemical reactions) with a plasma field (reactive species-driven reactions). The plasma provides highly reactive radicals that enable faster deposition rates without compromising the conformal deposition quality achieved in thermal ALD
2Productivity
If deposition temperature is increased to improve deposition rate, then deposition rate increases, but chemical precursors decompose
Solution Approach 1:
The patent changes the activation mechanism from thermal to plasma-based, allowing deposition to proceed at lower temperatures where precursors remain stable. The plasma provides the necessary activation energy through reactive species rather than thermal energy, preventing precursor decomposition while maintaining high deposition rates
Solution Approach 2:
The patent substitutes thermal activation with plasma activation, replacing the heat-driven reaction mechanism with a chemically-active plasma-driven mechanism. This substitution enables high deposition rates at lower temperatures, preserving precursor stability while achieving high productivity
3Productivity
If PE-ALD process is used to increase deposition rate, then deposition rate improves, but plasma damage to substrate occurs
Solution Approach 1:
The patent applies different electrical potentials to different regions of the chamber components (showerhead, plasma baffle, water box) to create localized plasma generation zones. This controlled local plasma generation delivers reactive species efficiently to the substrate for high deposition rates while limiting excessive plasma exposure that would cause damage
Solution Approach 2:
The patent employs periodic pulsing of reactant gases and plasma activation cycles. This periodic action allows controlled plasma exposure for deposition while providing intervals for purging and reducing cumulative plasma damage, maintaining high deposition rates with minimized substrate damage
4Productivity
If conventional CVD is used for deposition, then deposition rate is high, but conformal deposition on aggressive geometries is not achieved
Solution Approach 1:
The patent segments the deposition process into sequential half-reactions (precursor exposure followed by reactant exposure) characteristic of ALD. This segmentation enables precise control of reactant delivery to complex geometries, achieving conformal deposition while maintaining high overall deposition rates through plasma enhancement
Solution Approach 2:
The patent substitutes the continuous flow mechanism of CVD with the sequential, plasma-enhanced ALD mechanism. The plasma activation in each half-reaction ensures complete surface coverage and reactive termination, achieving conformal deposition on aggressive geometries with high deposition rates that rival or exceed conventional CVD
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 PE-ALD process enables faster deposition rates and improved conformality on substrates with aggressive geometries, while minimizing plasma damage and expanding the compatibility with chemical precursors, thus enhancing the throughput and efficiency of semiconductor and display processing.
Implementation Method 1
a reactant plasma is pulsed into the process chamber and reacts with the first reactant gas to form a deposited material
Implementation Method 2
A showerhead, a plasma baffle and a water box are positioned between the insulated components and become RF hot when activated by a plasma generator
Data Source
AI summary
Embodiments of the invention provide an apparatus configured to form a material during an atomic layer deposition (ALD) process, such as a plasma-enhanced ALD (PE-ALD) process. In one embodiment, a plasma baffle assembly for receiving a process gas within a plasma-enhanced vapor deposition chamber is provided which includes a plasma baffle plate containing an upper surface to receive a process gas and a lower surface to emit the process gas, a plurality of openings configured to flow the process gas from above the upper surface to below the lower surface, wherein each opening is positioned at a predetermined angle of a vertical axis that is perpendicular to the lower surface, and a conical nose cone on the upper surface. In one example, the openings are slots positioned at a predetermined angle to emit the process gas with a circular flow pattern.