Backside Inserts for Plasma Chamber Electrode Isolation
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Solution Overview
Problem
Plasma processing chambers face contamination issues due to abrasive contact between securing hardware and electrode material, leading to potential contamination sources and challenges in maintaining isolation of backside inserts and securing hardware from reactive species.
Innovation Solution
The use of backside inserts with threaded and tool-engaging features, including torque-receiving slots and lateral shielding portions, to prevent tool extension beyond the insert's periphery and ensure secure, non-destructive engagement and disengagement of the thermal control plate and showerhead electrode, while minimizing frictional contact and contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If securing hardware is used to attach the thermal control plate to the showerhead electrode, then the electrode assembly can be securely mounted, but abrasive contact between the securing hardware and electrode material causes contamination
Solution Approach 1:
The patent extracts the securing hardware from direct contact with the electrode material by introducing backside inserts as an intermediate layer. The securing hardware attaches to the backside inserts rather than directly to the electrode, eliminating abrasive contact and contamination while maintaining secure mounting through the insert-electrode interface.
Solution Approach 2:
The backside inserts serve as an intermediary component between the securing hardware and the showerhead electrode. This mediator allows the securing hardware to fasten the assembly securely while preventing direct abrasive contact with the electrode material, thus resolving the contamination issue without compromising mounting strength.
2Ease of operation
If tools are used to engage with the backside insert for installation and removal, then secure engagement is achieved, but tool extension beyond the insert periphery causes abrasion and contamination
Solution Approach 1:
The patent applies preliminary anti-action by designing lateral shielding portions that prevent the tool from extending beyond the insert periphery before abrasion can occur. The shielding portions physically block excessive tool penetration, preventing contact with the electrode material and eliminating the source of abrasion and contamination.
Solution Approach 2:
The lateral shielding portions convert the potential harm of tool extension into a beneficial feature by using the tool's own penetrating motion to engage with the torque-receiving slots while the shielding portions prevent over-penetration. The tool's engagement path is guided and limited, transforming what could be a contamination source into a controlled engagement mechanism.
3Ease of manufacture
If the showerhead electrode is designed as a single-piece component, then manufacturing is simplified, but maintenance and replacement of contaminated parts require complete electrode replacement
Solution Approach 1:
The patent segments the electrode assembly into distinct components: the showerhead electrode, backside inserts, and securing hardware. This segmentation allows the backside inserts and securing hardware to be independently replaced when contaminated, while the expensive showerhead electrode remains intact. The inserts can be accessed and replaced through the thermal control plate without removing the entire electrode assembly.
4Device complexity
If securing hardware directly contacts the electrode material, then simple attachment is achieved, but isolation of backside inserts from reactive species becomes difficult
Solution Approach 1:
The patent implements a nested structure where the backside inserts are positioned within recesses in the showerhead electrode, and the securing hardware attaches to the inserts rather than directly to the electrode. This nested arrangement creates physical barriers and isolation zones that protect the backside inserts and securing hardware from reactive species in the plasma environment while maintaining a relatively simple attachment mechanism.
Data Source
AI summary
A showerhead electrode is provided where backside inserts are positioned in backside recesses formed along the backside of the electrode. The backside inserts comprise a tool engaging portion. The tool engaging portion is formed such that the backside insert further comprises one or more lateral shielding portions between the tool engaging portion and the threaded outside diameter to prevent a tool engaged with the tool engaging portion of the backside insert from extending beyond the threaded outside diameter of the insert. Further, the tool engaging portion of the backside insert comprises a plurality of torque-receiving slots arranged about the axis of rotation of the backside insert. The torque-receiving slots are arranged to avoid on-axis rotation of the backside insert via opposing pairs of torque-receiving slots.