Optical Monitoring of WAP Ring Plunger Motion
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Solution Overview
Problem
Conventional dry etching apparatuses face issues with particle contamination due to small gaps between the top electrode and the WAP ring, caused by discrepancies in plunger shafts leading to oblique motion and scratching, which existing systems fail to precisely monitor and prevent.
Innovation Solution
An optical monitoring system using a light transceiver device and optical reflector elements affixed to plunger shafts, which detects abnormal motion by reflecting a light beam and triggering an alarm to prevent rubbing or scratching between the WAP ring and top electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gap between the top electrode and WAP ring is made very small to improve plasma confinement, then plasma confinement is improved, but particle contamination increases due to oblique motion and scratching caused by plunger shaft discrepancies
Solution Approach 1:
The optical monitoring system performs preliminary detection of plunger shaft motion abnormalities before they cause the WAP ring to scratch the top electrode. By detecting discrepancies in real-time during the descending and ascending motion, the system can alert operators or automatically stop the process before particle contamination occurs
Solution Approach 2:
The optical monitoring system establishes a feedback loop that continuously monitors the position and motion of plunger shafts and WAP ring. The light transceiver detects positional changes and provides real-time feedback about the horizontal alignment and motion smoothness, enabling corrective action before contamination occurs
2Device complexity
If conventional mechanical monitoring methods are used to detect plunger shaft motion, then device complexity is reduced, but measurement precision is insufficient to detect small discrepancies that cause oblique motion
Solution Approach 1:
The patent replaces conventional mechanical monitoring methods with an optical monitoring system. The light transceiver uses optical fields instead of mechanical contacts to detect the position and motion of plunger shafts and WAP ring, achieving high measurement precision without complex mechanical linkages
Solution Approach 2:
The optical monitoring system introduces light as an intermediary to detect plunger shaft motion. Instead of direct mechanical measurement, the system uses light reflection from the WAP ring to indirectly measure position and motion characteristics, achieving high precision with minimal intrusion
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
Effectively monitors and prevents particle contamination by ensuring horizontal and precise motion of the WAP ring, reducing the risk of chamber or wafer contamination through timely alerts and motion control.
Implementation Method 1
an optical monitoring system comprising a light transceiver device and optical reflector elements affixed to respective the lower rollers or the plunger shafts, wherein a light beam emanated from the light transceiver is reflected by the optical reflector elements and is re-directed back to the light transceiver device
Data Source
AI summary
An optical monitoring system includes a ring-shaped object suspended by and engaged with a plurality of vertical plunger shafts. Normally, the vertical plunger shafts move upward and downward reciprocally and coherently, but independently, such that the ring-shaped object ascends or descends horizontally. A light transceiver device is affixed to one vertical plunger shaft. A plurality optical reflector elements are affixed to respective other plunger shafts. A light beam emanated from said light transceiver is reflected by the optical reflector elements and is eventually re-directed back to the light transceiver device.