Tunable Bottom Shadow Ring for Plasma Sheath Etch Uniformity
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Solution Overview
Problem
Plasma etch tools experience defects in the perimeter region of semiconductor substrates due to electromagnetic profile discontinuities in the plasma sheath, leading to particulates and contamination during etching, which affect productivity and yield.
Innovation Solution
Incorporation of a combination bottom shadow ring component with a moveable inner ring and a fixed outer ring to adjust the plasma sheath's electromagnetic profile, enhancing verticality of ion bombardment and protecting beveled regions, using a mechanical lift component and machine learning for precise adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plasma etch tool uses a plasma-assisted etch technique to etch semiconductor substrates, then etching capability is achieved, but electromagnetic profile discontinuities in the plasma sheath cause etch defects in the perimeter region
Solution Approach 1:
The patent applies local quality by implementing different ring component heights at different radial positions within the plasma sheath. The inner ring component has a first height and the outer ring component has a second height, creating localized electromagnetic field adjustments in specific regions (perimeter vs. center) of the substrate to control ion bombardment angles and eliminate etch defects in the perimeter region while maintaining overall etching capability
Solution Approach 2:
The patent changes physical parameters of the plasma sheath by adjusting the heights of the inner and outer ring components. By varying the height parameter of these ring structures, the electromagnetic profile of the plasma sheath is modified to achieve continuous profiles that prevent etch defects, thereby resolving the contradiction between maintaining etching capability and eliminating perimeter region defects
2Manufacturing precision
If the plasma sheath electromagnetic profile is adjusted to eliminate etch defects, then etch quality improves, but device complexity increases due to additional ring components
Solution Approach 1:
The patent segments the plasma sheath modification function into distinct inner and outer ring components with different heights. This segmentation allows independent optimization of electromagnetic profiles in different radial zones, achieving continuous plasma sheath profiles that eliminate etch defects while keeping each ring component's structure relatively simple and manageable
Solution Approach 2:
The ring components serve multiple functions: they physically support the plasma sheath structure, generate the electromagnetic field modifications needed for continuous profiles, and protect the substrate perimeter region. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved etch quality
3Adaptability or versatility
If recipe changes require downtime for adjustment, then process flexibility is maintained, but productivity decreases due to lost time
Solution Approach 1:
The patent implements dynamics by making the ring components height-adjustable rather than fixed. This allows the system to dynamically reconfigure the plasma sheath electromagnetic profile for different etch recipes without requiring physical component replacement or extensive reconfiguration, thereby maintaining process flexibility while minimizing downtime and maximizing productivity
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
Reduces etch defects, increases productivity by eliminating downtime for recipe changes, and enhances yield by minimizing particulates and contamination, thus reducing resource requirements.
Implementation Method 1
electromagnetic profile of the plasma sheath
Implementation Method 2
electrons may be depleted from a boundary interface between an electrode of the etch tool and the plasma to create a region that contains positive ions and neutrals. This region may be referred to as a plasma sheath
Data Source
AI summary
Some implementations described herein include an etch tool including a combination bottom shadow ring component including a moveable inner ring component and a fixed inner ring component. The moveable inner ring component provides for an adjustability of an effective thickness of the combination bottom shadow ring component during an etching operation. The adjustability (e.g., “tunability”) of the effective thickness of the combination bottom shadow ring component enables flexibility and is conducive to changes in one or more parameters related to different etch recipes for a semiconductor substrate. Additionally, the fixed inner ring component shadows beveled regions of the semiconductor substrate during the etching operation to reduce a likelihood of damage to the beveled regions.