Plasma Lining Structure for Wafer Edge Tilt Control
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Solution Overview
Problem
Current methods for controlling local and global tilts in three-dimensional (3D) devices during plasma etching are insufficient, particularly at the wafer edge, leading to challenges in tilt specification and etch rate uniformity.
Innovation Solution
A plasma lining structure is introduced to cover the inner surface of a plasma confinement structure, blocking the horizontal line-of-sight of plasma to the grounded sidewall and preserving the ground return path, thereby suppressing plasma density at the edge region and improving local tilt control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma confinement structure with exposed sidewall is used, then plasma generation is efficient, but plasma density at wafer edge is excessive causing poor tilt control
Solution Approach 1:
A dielectric liner is introduced as an intermediary component between the plasma confinement structure's sidewall and the plasma. This liner blocks the direct line-of-sight path for plasma to reach the grounded sidewall, thereby suppressing excessive plasma density at the wafer edge region while preserving the ground return path through the liner to the ground ring, achieving improved tilt control.
2Manufacturing precision
If ground return path is blocked to suppress plasma, then plasma density control improves, but plasma generation efficiency deteriorates
Solution Approach 1:
The dielectric liner is selectively positioned only at the sidewall region where plasma density needs suppression (wafer edge area), while the ground return path is preserved through the liner to the ground ring. This localized application allows plasma density uniformity improvement without compromising overall plasma generation efficiency and etch rate.
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
This approach enhances etch rate uniformity and improves tilt profile in the edge region of 3D devices by concurrently controlling global and local tilts, providing better local tilt control than traditional dynamic knobs or settings.
Implementation Method 1
A plasma lining structure is provided to block a line-of-sight to at least a portion of an inner surface of a sidewall of the plasma confinement structure, for the wafer area plasma, thereby blocking the plasma's path to ground.
Data Source
AI summary
A plasma lining structure is used in a process chamber to block direct line-of-sight for plasma generated within to grounded surface. The plasma lining structure includes a plurality of sections to cover at least one or more portions of an inside surface of a plasma confinement structure disposed in the process chamber. The sections of the plasma lining structure are positioned between a plasma region and the sidewall of the plasma confinement structure, when the plasma lining structure and the plasma confinement structure are disposed in the plasma chamber, such that the sections directly face the plasma region.