Plasma Processing Ring Thickness Measurement Using Jig and Elevating Mechanism
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Solution Overview
Problem
Conventional plasma processing apparatuses face challenges in accurately measuring the thickness of ring members, such as focus rings, which affects the uniformity of plasma processing and etching characteristics due to consumption during plasma processing.
Innovation Solution
A plasma processing apparatus with a mounting table, elevating mechanisms, an acquisition unit for gap information, a measurement unit to measure the lifted distance of the ring member, and a thickness calculation unit to determine the ring member's thickness based on gap dimension and lifted distance, allowing for precise measurement and maintenance of the ring member's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a focus ring is used to make plasma uniform, then plasma uniformity is improved, but the focus ring is quickly consumed and thickness measurement becomes difficult
Solution Approach 1:
The patent applies preliminary action by measuring the thickness of the focus ring before plasma processing using a jig with a measurement probe. This allows the thickness to be known in advance, enabling proactive adjustment of the focus ring position to compensate for expected consumption during processing, thereby maintaining plasma uniformity throughout the operation.
Solution Approach 2:
The patent implements feedback by continuously monitoring the focus ring thickness through repeated measurements with the jig and using this information to adjust the focus ring's vertical position. The control unit processes thickness data and automatically adjusts the focus ring height to maintain optimal plasma uniformity, creating a closed-loop control system that compensates for consumption in real-time.
2Stability of the object's composition
If the focus ring is lifted to compensate for consumption, then plasma uniformity is maintained, but the complexity of the apparatus increases
Solution Approach 1:
The patent applies universality by designing the jig to serve multiple functions: it acts as both a measurement probe for thickness detection and a positioning reference for the focus ring. The same jig structure is used to both measure the ring thickness and provide the reference surface against which the ring position is adjusted, eliminating the need for separate measurement and positioning devices.
Solution Approach 2:
The system applies self-service by using the focus ring itself as part of the measurement process. The ring's own upper surface serves as the measurement reference surface, and the ring's weight and position automatically provide feedback about its consumption state. The control unit automatically processes the measurement data and adjusts the ring position without requiring manual intervention, making the system self-regulating.
3Device complexity
If manual measurement methods are used for focus ring thickness, then the apparatus remains simple, but measurement precision deteriorates
Solution Approach 1:
The patent applies mechanics substitution by replacing manual caliper or micrometer measurements with an automated probe-based measurement system. The measurement probe automatically contacts the focus ring and the control unit calculates thickness based on the probe's position and the jig's known geometry, eliminating human error and providing consistent, precise measurements without requiring complex optical or electronic equipment.
Data Source
AI summary
In a plasma processing apparatus, a mounting table have a first mounting surface on which a target object or a jig is mounted and a second mounting surface on which a ring member is mounted. The jig is used for measuring a thickness of the ring member disposed around the target object and having a facing portion facing an upper surface of the ring member. Elevating mechanisms lift or lower the ring member with respect to the second mounting surface. An acquisition unit acquires gap information indicating a gap dimension between the second mounting surface and the facing portion of the jig. A measurement unit measures a lifted distance of the ring member from the second mounting surface. A thickness calculation unit calculates the thickness of the ring member based on the gap dimension and the measured lifted distance of the ring member.