ICP Plasma Reactor Baffle for Gas Distribution Uniformity
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Solution Overview
Problem
Inductively-coupled plasma (ICP) chambers face challenges in achieving uniform gas distribution, leading to non-uniform processing results across the substrate, as gas injected from circumference injectors is largely pumped out and fails to reach the center, while central nozzle gas is concentrated at the center but not at the edge, resulting in processing non-uniformity.
Innovation Solution
A plasma reactor design featuring a dielectric window with a circular baffle positioned inside the chamber to redirect and constrict the gas flow from injectors, ensuring even distribution across the substrate, with the baffle optionally being made of conductive or dielectric materials and featuring adjustable openings and extensions to control gas flow and plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gas is supplied through circumference injectors, then gas is injected into the chamber, but the gas is largely pumped out and does not reach the center of the substrate, resulting in non-uniform gas distribution
Solution Approach 1:
A baffle structure is introduced as an intermediary element between the gas injectors and the substrate. The baffle redirects the gas flow paths, causing gas from circumference injectors to reach the center region and gas from central injectors to distribute toward the edges, thereby achieving uniform gas distribution across the substrate surface
Solution Approach 2:
The gas distribution problem is segmented by introducing a baffle with specific geometric features (central opening, annular opening, vertical wall) that divides and redirects gas flow into different regions. This segmentation of flow paths enables independent control of gas distribution to different zones of the substrate
2Quantity of substance
If gas is supplied through a central nozzle, then gas is concentrated at the center of the substrate, but the gas does not reach the edge of the substrate, resulting in non-uniform processing
Solution Approach 1:
The baffle acts as a mediator that redirects gas flow from the central nozzle. The vertical wall and annular opening of the baffle guide the centrally-concentrated gas toward the edge regions of the substrate, ensuring adequate gas supply at the edges while maintaining some central concentration
Solution Approach 2:
The baffle introduces a vertical dimension to gas flow control by positioning itself between the horizontal injector plane and the substrate. The vertical wall and openings create three-dimensional flow paths that redirect gas in multiple directions, enabling gas to reach both center and edge regions
3Power
If a dielectric window is provided in the ceiling for RF power transmission, then RF power can be coupled into the chamber, but showerhead gas injection cannot be implemented, limiting gas distribution options
Solution Approach 1:
The ceiling structure is segmented by providing a dielectric window within it, allowing RF power transmission through the ceiling while maintaining the structural integrity for gas injector mounting. This segmentation enables both RF coupling and flexible gas injection configurations including central nozzles, circumference injectors, and the baffle structure
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 baffle enhances gas distribution uniformity within the ICP chamber, improving processing uniformity by redirecting gas to reach both the center and edge of the substrate effectively, thereby improving within-wafer uniformity and plasma dissociation.
Implementation Method 1
A plasma reactor design featuring a dielectric window with a circular baffle positioned inside the chamber to redirect and constrict the gas flow from injectors
Implementation Method 2
an antenna, usually in the form of a coil, is used to transmit the RF power into the chamber. In order to couple the RF power from the antenna into the chamber, a dielectric window is provided
Implementation Method 3
various gasses are injected into the chamber so that chemical and/or physical interaction of ions with the substrate can be used to generate various features on the substrate
Data Source
AI summary
An ICP A plasma reactor having an enclosure wherein at least part of the ceiling forms a dielectric window. A substrate support is positioned within the enclosure below the dielectric window. An RF power applicator is positioned above the dielectric window to radiate RF power through the dielectric window and into the enclosure. A plurality of gas injectors are distributed uniformly above the substrate support to supply processing gas into the enclosure. A circular baffle is situated inside the enclosure and positioned above the substrate support but below the plraity of gas injectors so as to redirect the flow of the processing gas.