Contoured Showerhead Faceplate for Plasma Uniformity
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Solution Overview
Problem
Semiconductor processing tools face non-uniformities in plasma density and deposition rates due to the flat profile of traditional showerhead faceplates, leading to variations in deposition layer thickness across substrates.
Innovation Solution
A method to produce contoured showerhead faceplates by determining a contour profile based on deposition rate data, which involves obtaining first and second deposition rate data, calculating gap distance deltas, and manufacturing a faceplate with a surface defined by this contour profile to modulate plasma density and achieve uniform deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flat showerhead faceplate is used, then the manufacturing is simple and the structure is easy, but the plasma density becomes non-uniform and deposition layer thickness varies across the substrate
Solution Approach 1:
The showerhead faceplate is designed with a contoured surface where different regions have different heights relative to the substrate. This creates location-specific plasma sheath gaps that compensate for positional variations, ensuring uniform plasma density and deposition across the entire substrate surface.
Solution Approach 2:
The faceplate surface is contoured with curved profiles rather than being flat. This curvature is specifically designed to adjust the gap distance between the faceplate and substrate at different locations, optimizing plasma distribution uniformity across the substrate area.
2Manufacturing precision
If the gap distance between showerhead and substrate is increased, then plasma density decreases, but deposition uniformity improves in certain regions
Solution Approach 1:
Different regions of the faceplate are positioned at different heights to create location-specific gap distances. Regions with higher plasma density have the faceplate positioned closer to the substrate, while regions with lower density have it positioned farther away, achieving uniform plasma density across all regions while maintaining overall high deposition rates.
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 contoured showerhead faceplates significantly reduce non-uniformities in deposition layer thickness, providing more uniform plasma density and improved semiconductor processing results compared to traditional flat faceplates.
Implementation Method 1
a capacitively-coupled plasma (CCP) system and process
Implementation Method 2
The resulting plasma sheath may be used to process the semiconductor substrate
Implementation Method 3
An electric field may be generated between the wafer and the showerhead, thereby ionizing the process gas and forming a plasma
Data Source
AI summary
Semiconductor processing chamber showerheads with contoured faceplates, as well as techniques for producing such faceplates, are provided. Data describing deposition rate as a function of gap distance between a reference showerhead faceplate and a reference substrate may be obtained, as well as data describing deposition rate as a function of location on the substrate when the reference showerhead and the reference substrate are in a fixed arrangement with respect to each other. The two data sets may be used to determine offsets from a reference plane associated with the faceplate that determine a contour profile to be used with the faceplate.