Preclean Chamber Upper Shield Showerhead for Uniform Plasma Flow
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Solution Overview
Problem
Existing process kits for substrate processing chambers interfere with the uniform flow of process gases, potentially leading to non-uniform plasma distribution and contamination deposition on chamber surfaces during preclean and plasma cleaning processes.
Innovation Solution
A process kit design featuring a top plate with a central recess, channels, and a tubular body surrounding the substrate support, which includes a gas flow path through multiple holes arranged in concentric circles, ensuring high conductance and minimizing plasma leaks while preventing contaminant deposition on chamber surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If process kits are used to prevent contaminant deposition on chamber surfaces, then contamination is reduced, but gas flow uniformity is compromised
Solution Approach 1:
The upper shield is segmented into multiple functional zones: a showerhead portion with gas distribution holes for uniform gas flow, a process kit portion with shield openings for contaminant prevention, and a plenum chamber for gas reservoir. This segmentation allows each zone to perform its specific function optimally without interfering with others.
Solution Approach 2:
Different regions of the upper shield have different properties: the showerhead portion has numerous small holes for gas distribution, the process kit portion has larger shield openings for contamination control, and the plenum has a sealed recess for gas accumulation. Each region's structure is optimized for its local function while maintaining overall system performance.
2Object-affected harmful factors
If process kits are used to shield chamber surfaces, then contamination is prevented, but plasma distribution uniformity deteriorates
Solution Approach 1:
The process kit structure is nested within the upper shield assembly, with the showerhead portion containing the plenum chamber recess, which in turn contains the gas distribution holes. This nested configuration allows the process kit to provide shielding functionality while the inner showerhead structure maintains plasma distribution uniformity through controlled gas flow paths.
Solution Approach 2:
The plenum chamber acts as an intermediary between the gas supply and the substrate, providing a reservoir that ensures uniform gas pressure and flow distribution. This intermediary structure mediates between the gas source and the processing zone, maintaining plasma uniformity while the outer process kit portion provides contamination shielding.
3Object-affected harmful factors
If complex process kit structures are used to prevent contamination, then shielding is improved, but device complexity increases
Solution Approach 1:
The upper shield assembly serves multiple functions simultaneously: the showerhead portion distributes process gas uniformly, the process kit portion shields chamber surfaces from contaminants, and the plenum chamber reservoirs gas for stable flow. This multi-functionality is achieved within a single integrated structure rather than requiring separate components for each function.
Solution Approach 2:
The patent merges the showerhead, process kit, and plenum chamber into a single integrated upper shield assembly. This combination consolidates multiple functions into one component, reducing the number of separate parts and simplifying the overall device structure while maintaining all necessary functionalities for gas distribution, shielding, and plasma uniformity.
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 design enhances gas flow conductance and uniform plasma distribution, reducing contamination deposition and maintaining chamber vacuum integrity during substrate processing, thereby improving process efficiency and substrate quality.
Implementation Method 1
Electromagnetic energy (e.g., radio frequency) is applied to an injected gas, such as argon, to excite the injected gas into a plasma state. The plasma releases ions that bombard the surface of the substrate to remove contaminants and/or material from the substrate.
Implementation Method 2
a gas flow path extends from the channel to the plenum, through the plurality of holes, and into a volume within the tubular body
Data Source
AI summary
Embodiments of process kits for use in a process chamber are provided herein. In some embodiments, a process kit for use in a process chamber, includes: a top plate having a central recess disposed in an upper surface thereof; a channel extending from an outer portion of the top plate to the central recess; a plurality of holes disposed through the top plate from a bottom surface of the recess to a lower surface of the top plate; a cover plate configured to be coupled to the top plate and to form a seal along a periphery of the central recess such that the covered recess forms a plenum within the top plate; and a tubular body extending down from the lower surface of the top plate and surrounding the plurality of holes, the tubular body further configured to surround a substrate support.