Edge Ring Sheath Control for Uniform Semiconductor Etching
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Solution Overview
Problem
As semiconductor devices undergo etching processes, the curvature of the electrical field and sheath at the edge region of the wafer leads to non-perpendicular ion impact, resulting in non-uniform patterning and potential damage, affecting the integration density and uniformity of electronic components.
Innovation Solution
A high electron mobility material edge ring is placed adjacent to the electrostatic chuck to extend and adjust the sheath curvature, ensuring ions are accelerated perpendicular to the substrate, maintaining uniformity across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching process is performed on semiconductor wafer, then circuit components are formed, but non-uniform patterning occurs at edge region due to sheath curvature
Solution Approach 1:
The patent applies local quality by making the edge ring electrically conductive while the central chuck remains electrically isolated. This creates different electrical properties in different regions of the support structure, allowing the edge region to have enhanced electron mobility and sheath control specifically where needed, without affecting the central processing area.
Solution Approach 2:
The electrically conductive edge ring acts as an intermediary element between the electrostatic chuck and the plasma environment. It mediates the electrical field distribution at the wafer periphery, extending the sheath and directing ion acceleration perpendicular to the substrate surface, thereby eliminating the non-uniform patterning caused by sheath curvature.
2Productivity
If minimum feature size is reduced to improve integration density, then more components are integrated, but additional process problems arise
Solution Approach 1:
The patent changes the electrical conductivity parameter of the support structure by introducing an electrically conductive edge ring. This parameter change modifies the plasma sheath characteristics and ion acceleration behavior, enabling precise control of the etching process even at reduced minimum feature sizes, thereby maintaining manufacturing precision while improving integration density.
3Manufacturing precision
If sheath curvature is not adjusted, then etching process is simple, but ion impact is non-perpendicular causing non-uniform patterning
Solution Approach 1:
The support structure is segmented into two distinct functional zones: the central electrostatic chuck for general wafer support and the peripheral electrically conductive edge ring for sheath control. This segmentation allows each zone to perform its specific function independently, achieving perpendicular ion impact and uniform etching without requiring complex integrated control systems.
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 solution achieves a more uniform etching profile and reduces ion crowding near the wafer edges, enhancing the precision and uniformity of gate electrode formation, thereby improving the integration density and reducing variability in semiconductor device manufacturing.
Implementation Method 1
providing a first chuck, the first chuck comprising a first electrode to generate a sheath over the first chuck
Implementation Method 2
the first edge ring is formed of a high electron mobility material and is electrically isolated from the first chuck
Data Source
AI summary
A semiconductor manufacturing tool and process to form semiconductor devices is provided. An edge ring of the semiconductor manufacturing tool comprises a high electron mobility material in order to extend an electrical field and sheath such that curvature from the sheath is moved away from a semiconductor wafer so that an impact from the curvature is reduced or eliminated during an etching process.