Tunable PEZ Ring Geometry for Bevel Etch Distance Control
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Solution Overview
Problem
In semiconductor substrate processing, the accumulation of byproduct layers on the bevel edge leads to contamination during substrate transport due to weakened bonds between these layers and the substrate, as plasma etch density is lower near the edge, causing peeling or flaking off.
Innovation Solution
A tunable upper plasma-exclusion-zone (PEZ) ring for a bevel etcher is introduced, featuring a lower surface with an upwardly tapered portion that adjusts the gap between the PEZ ring and the substrate, allowing for varying etch distances without changing the PEZ ring diameter, enabling multiple etching processes in a single chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-diameter PEZ ring is used for bevel etching, then the plasma exclusion zone is stable, but the etch distance cannot be adjusted without replacing the PEZ ring
Solution Approach 1:
The PEZ ring is designed with a movable outer peripheral edge that can be dynamically adjusted radially outward or inward relative to the substrate. This dynamic positioning capability allows the etch distance to be varied without replacing the PEZ ring, resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The PEZ ring structure is segmented into a fixed central portion and a movable outer peripheral edge. This segmentation allows independent adjustment of the outer edge position while maintaining the structural integrity of the overall ring, enabling etch distance variation without complete ring replacement.
2Adaptability or versatility
If multiple PEZ rings are used to achieve different etch distances, then etch distance flexibility is improved, but device complexity and contamination risk increase
Solution Approach 1:
A single PEZ ring is designed to perform multiple functions by adjusting the radial position of its outer peripheral edge. This multi-functionality eliminates the need for multiple separate PEZ rings, thereby reducing contamination risk from ring transfers while maintaining etch distance flexibility.
Solution Approach 2:
The movable outer peripheral edge acts as an intermediary mechanism between the fixed PEZ ring structure and the variable etch distance requirement. By adjusting this intermediary element, different etch distances can be achieved without introducing new PEZ rings into the system.
3Productivity
If plasma density is uniform across the substrate, then etching efficiency is high, but byproduct accumulation occurs at the bevel edge
Solution Approach 1:
The PEZ ring creates a localized plasma exclusion zone at the bevel edge region, while the central substrate area maintains high plasma density for efficient etching. This local modification of plasma distribution prevents byproduct accumulation at the edge without sacrificing overall etching productivity.
Solution Approach 2:
The PEZ ring converts the harmful effect of plasma exposure at the bevel edge (which causes byproduct accumulation) into a beneficial plasma exclusion zone. By deliberately creating this exclusion area, the system prevents edge contamination while maintaining efficient etching in the productive regions.
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 effectively controls etch distance and reduces contamination by adjusting the radial extent of plasma exposure, allowing for precise etching without the need for multiple PEZ rings or chamber transfers, enhancing process flexibility and reducing contamination risks.
Implementation Method 1
a tunable upper plasma exclusion zone (PEZ) ring surrounds the bottom portion of the upper dielectric component
Implementation Method 2
a lower surface of the tunable upper PEZ ring includes an upwardly tapered outer portion extending outwardly from the bottom portion of the upper dielectric component
Implementation Method 3
At least one radio frequency (RF) power source is adapted to energize process gas into the plasma during a bevel edge cleaning process
Data Source
AI summary
A tunable upper plasma exclusion zone (PEZ) ring adjusts a distance of plasma during processing in a processing chamber and includes: a lower surface that includes: a horizontal portion; and an upwardly tapered outer portion that is conical and that extends outwardly and upwardly from the horizontal portion at an upward taper angle of about 5° to 50° with respect to the horizontal portion, where an outer diameter of the upwardly tapered outer portion is greater than 300 millimeters (mm), and where an inner diameter where the upwardly tapered outer portion begins to extend upwardly is less than 300 mm. A controller is to, during processing of a 300 mm circular substrate, adjust the distance of plasma for treatment of the 300 mm circular substrate at least one of radially inward and radially outward using the tunable upper PEZ ring.