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 weakened bonds and contamination during substrate transport, as etch plasma density is lower near the edge, causing these layers to peel or flake off onto other substrates.
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, then the chamber can perform only limited etching processes, but changing the PEZ ring diameter requires multiple rings and increased device complexity
Solution Approach 1:
The patent applies the dynamics principle by making the PEZ ring expandable and adjustable in diameter. The ring transitions from a fixed structure to a dynamic one that can change its size during operation. This is achieved through expandable structures that allow the PEZ ring to adapt to different etching process requirements without requiring multiple separate rings, thereby resolving the contradiction between versatility and device complexity.
Solution Approach 2:
The patent implements parameter changes by enabling continuous adjustment of the PEZ ring diameter. Instead of discrete fixed sizes, the ring diameter can be varied continuously to match different substrate sizes and etching process requirements. This parameter adjustability allows a single ring structure to perform multiple etching processes that would traditionally require multiple fixed-diameter rings.
2Area of stationary object
If the PEZ ring diameter is increased to accommodate larger substrates, then larger substrates can be processed, but the etch distance for smaller substrates becomes excessive
Solution Approach 1:
The dynamics principle resolves this contradiction by enabling the PEZ ring diameter to be dynamically adjusted according to the substrate size being processed. For larger substrates, the ring expands to provide adequate coverage; for smaller substrates, the ring contracts to maintain optimal etch distance. This dynamic adaptation ensures both large substrate capability and precise etch distance control are achieved with a single adjustable ring.
Solution Approach 2:
The parameter changes principle is applied by making the PEZ ring diameter a variable parameter rather than a fixed value. The diameter can be continuously changed to match the substrate size, ensuring that the etch distance remains within the optimal range regardless of whether small or large substrates are being processed. This eliminates the need to compromise on etch distance precision when accommodating larger substrates.
3Adaptability or versatility
If multiple fixed-diameter PEZ rings are stored in the chamber, then different etching processes can be performed, but substrate handling and ring replacement time increase
Solution Approach 1:
The dynamics principle eliminates the need for physical ring replacements by providing a single PEZ ring that can dynamically change its diameter. Instead of storing and swapping multiple fixed-diameter rings, the system uses one adjustable ring that adapts to different etching process requirements in real-time. This eliminates substrate handling time associated with ring changes while maintaining the ability to perform various etching processes.
Solution Approach 2:
The universality principle is applied by designing a single PEZ ring that can perform multiple functions across different etching processes. Rather than requiring separate specialized rings for different substrate sizes and process types, the adjustable ring serves as a universal component that can be configured for various applications, thereby eliminating the time loss associated with switching between multiple specialized rings.
4Ease of operation
If the gap between PEZ ring and substrate is fixed, then the structure is simple, but the etch distance cannot be adjusted for different processes
Solution Approach 1:
The dynamics principle is applied by making the gap between the PEZ ring and substrate dynamically adjustable. The gap can be varied during operation to optimize etch distance for different processes and substrate configurations. This dynamic adjustability provides operational flexibility without requiring overly complex mechanisms, as the adjustment is integrated into the overall expandable PEZ ring structure.
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 allows for precise control of etch distance and extends the range of etching processes that can be performed in a single chamber, reducing contamination and substrate handling needs by adjusting the gap height, thereby enhancing process flexibility and efficiency.
Implementation Method 1
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.