Substrate Pusher Magnetic Seating Detection Against Slurry Interference
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Solution Overview
Problem
Existing substrate processing apparatuses face inaccuracies in detecting the seating of substrates due to diffuse reflection of light by cleaning water or slurry, leading to erroneous detection using optical sensors.
Innovation Solution
A pusher with seating members that utilize magnets and magnetic sensors to detect substrate seating, positioned away from the seating area to avoid interference from cleaning water or slurry, enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical sensors are used to detect substrate seating, then the detection mechanism is simple and cost-effective, but detection accuracy deteriorates due to diffuse reflection of light by cleaning water or slurry
Solution Approach 1:
The patent replaces the optical sensor system with a magnetic detection system. A magnet is attached to the movable portion that contacts the substrate, and a magnetic sensor detects the magnet's position. This substitution eliminates the problem of light diffusion by cleaning water or slurry, as magnetic fields are not affected by these substances, thereby maintaining detection simplicity while significantly improving seating detection accuracy.
Solution Approach 2:
The patent introduces a magnet as an intermediary element between the detection system and the substrate. Instead of directly detecting the substrate's position using light, the system detects the magnet's position, which in turn reflects the substrate's seating state. This intermediary approach allows accurate detection without direct optical interaction with the contaminated environment.
2Measurement precision
If magnets are positioned close to the seating area for detection, then detection sensitivity increases, but detection accuracy decreases due to interference from cleaning water or slurry
Solution Approach 1:
The magnet serves as an intermediary that is magnetically coupled to the movable portion but positioned away from the direct path of cleaning water or slurry. The magnetic field extends to the seating area, providing sensitive detection, while the physical magnet remains in a cleaner environment, reducing interference from cleaning water or slurry.
Solution Approach 2:
By using magnetic field interaction instead of direct physical contact or optical interaction in the contaminated area, the system achieves both high sensitivity (through close magnetic coupling) and resistance to interference (by keeping the magnetic sensor away from cleaning water or slurry).
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
Improves seating detection accuracy, reducing tact time and preventing erroneous substrate handling, allowing for precise substrate positioning and handling in the processing apparatus.
Implementation Method 1
a seating sensor configured to detect movement of the magnet
Implementation Method 2
a magnetic member disposed to shield a part of a portion between a movable region of the magnet and the seating sensor
Data Source
AI summary
A pusher that holds a substrate includes: a pusher body, and a plurality of seating members that is attached to the pusher body and on which a substrate is seated. Each of the plurality of seating members includes: a pedestal member including a seating portion on which the substrate is seated and a magnet disposed at a position different from the seating portion, and supported by the pusher body such that the position of the magnet is moved according to seating or leaving of the substrate; a seating sensor configured to detect movement of the magnet; and a magnetic member disposed to shield a portion between a movable region of the magnet and the seating sensor.