Plasma Etching Uniformity with Supplemental Electric Fields
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Summary
Problems
Plasma etching processes face challenges in maintaining uniformity across a wafer, leading to poorly functioning integrated circuits due to variations in the plasma sheath at the edge of the wafer, causing misalignment and non-uniform feature formation.
Innovation solutions
A supplemental electric field is applied above the focus ring and the edge of the wafer to straighten the plasma sheath, ensuring uniform ion trajectories and consistent feature formation across the wafer, using a system with a bottom electrode, top electrode, and a supplemental electrode to generate and control the electric fields.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If plasma etching is used to define small features in integrated circuits, then feature size reduction is achieved, but uniformity across the wafer deteriorates
Why choose this principle:
The patent applies different electric field conditions to different regions of the wafer by positioning electrodes at specific locations (edge zone and center zone). The edge zone electrode receives a first voltage while the center zone electrode receives a second voltage, creating locally optimized plasma sheath characteristics for each region to compensate for edge effects and improve overall uniformity.
Principle concept:
If plasma etching is used to define small features in integrated circuits, then feature size reduction is achieved, but uniformity across the wafer deteriorates
Why choose this principle:
The patent changes the electrical parameters (voltage) applied to different zones of the plasma etching chamber. By adjusting the voltage at the edge zone electrode relative to the center zone electrode, the plasma sheath thickness and electric field distribution are modified to achieve uniform etching across the wafer surface.
Application Domain
Data Source
AI summary:
A supplemental electric field is applied above the focus ring and the edge of the wafer to straighten the plasma sheath, ensuring uniform ion trajectories and consistent feature formation across the wafer, using a system with a bottom electrode, top electrode, and a supplemental electrode to generate and control the electric fields.
Abstract
A plasma etching system generates a plasma above a wafer in a plasma etching chamber. The wafer is surrounded by a focus ring. The plasma etching system straightens a plasma sheath above the focus ring by generating a supplemental electric field above the focus ring.