Plasma Confinement Ring Slit Geometry for Wafer Edge Uniformity
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving uniform plasma distribution and preventing plasma concentration on the edge regions of wafers, which can affect the quality and consistency of semiconductor devices.
Innovation Solution
A plasma confinement ring with a lower ring, upper ring, and connection ring, featuring variable thickness slits that allow controlled plasma discharge to underlying regions, thereby managing plasma distribution and reducing edge concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plasma confinement ring with uniform thickness is used, then the structure is simple and easy to manufacture, but the plasma density becomes concentrated on the edge region of the wafer, reducing uniformity
Solution Approach 1:
The plasma confinement ring employs variable thickness design where the ring thickness changes in different regions. Specifically, the ring has a first thickness in a first region and a second thickness in a second region, with the thickness ratio between 0.3:1 and 2:1. This local variation in thickness creates corresponding variations in plasma discharge characteristics, allowing the plasma density to be uniformly distributed across the wafer surface by compensating for edge concentration effects.
2Manufacturing precision
If the plasma confinement ring has variable thickness to improve plasma uniformity, then plasma distribution is improved, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The invention changes the geometric parameter of the confinement ring from uniform thickness to variable thickness. The thickness is designed to vary systematically across different regions of the ring, with specific thickness ratios (0.3:1 to 2:1) optimized to achieve uniform plasma discharge. This parameter change allows the system to compensate for natural plasma concentration effects without requiring complex active control mechanisms.
3Manufacturing precision
If slits are added to the plasma confinement ring to discharge plasma, then plasma distribution is controlled, but the structural complexity increases
Solution Approach 1:
The plasma confinement ring incorporates slits that segment the ring structure into multiple regions. These slits allow controlled discharge of plasma to underlying regions while maintaining the overall confinement function. The slits are positioned and dimensioned to work in conjunction with the variable thickness design, creating distinct plasma discharge pathways that contribute to uniform plasma distribution across the wafer surface.
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 solution enhances plasma uniformity and reduces plasma density near the wafer edge, ensuring consistent and uniform processing of semiconductor devices.
Implementation Method 1
a plasma confinement ring is used to confine the plasma within a region on the wafer or to prevent the plasma from being produced outside the wafer
Implementation Method 2
A thickness of the lower ring may be smaller at a first region closer to the lower center hole than a second region farther from the lower center hole
Data Source
AI summary
A plasma confinement ring includes a lower ring, an upper ring on the lower ring, and a connection ring extended to connect the lower ring to the upper ring. The lower ring includes a lower center hole vertically penetrating the lower ring at a center of the lower ring and at least one slit penetrating the lower ring in a region outside the lower center hole. The slit is structured to pass a more amount of air or gas at a first portion closer to the center of the lower ring than at a second portion farther from the center of the lower ring.