Lift Pin Intermediate Position for Substrate Detachment
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Solution Overview
Problem
In substrate processing, lift pins struggle to detach substrates from vacuum suction tables without damaging them due to water or backing material interference, leading to inefficient substrate transfer.
Innovation Solution
The use of lift pins with a distal end for guiding and a proximal end for holding, capable of being stopped at intermediate positions to manage vacuum pressure and fluid supply, allowing controlled detachment and placement of substrates without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lift pins are used to detach substrate from vacuum suction table, then substrate transfer is enabled, but substrate may be damaged by lift pins due to water or backing material interference
Solution Approach 1:
The lift pins are raised to an intermediate position before vacuum release to establish proper alignment and guidance. This preliminary positioning ensures the substrate is correctly oriented and the lift pins are properly engaged with the substrate periphery before the vacuum is released and the substrate is fully detached, preventing damage during the transfer process.
Solution Approach 2:
The intermediate position acts as a mediator state between the retracted and elevated positions. At this intermediate position, the substrate guide surfaces are above the suction surface while the substrate holding surfaces are below, creating a transitional state that allows controlled vacuum release and prevents direct impact between the lift pins and substrate that could cause damage.
2Productivity
If lift pins move continuously between upper and lower positions, then transfer efficiency is improved, but substrate placement and detachment control is reduced
Solution Approach 1:
The continuous movement of lift pins is segmented into distinct phases: retraction to lower position, movement to intermediate position, vacuum release, substrate detachment, and elevation to upper position. This segmentation allows for controlled transitions at each stage, ensuring proper substrate placement and detachment while maintaining overall transfer efficiency.
Solution Approach 2:
The lift pin system uses dynamic positioning with three distinct positions (lower, intermediate, upper) rather than simple binary movement. The ability to stop at the intermediate position during the detachment process provides dynamic control over the substrate transfer, allowing the system to adapt to the specific requirements of placement and detachment while maintaining productivity.
3Speed
If vacuum is released immediately when lift pins elevate, then detachment speed is improved, but substrate may slide or become misaligned
Solution Approach 1:
The lift pins are raised to the intermediate position before vacuum release to establish proper alignment and guidance. This preliminary positioning ensures the substrate is correctly oriented and the lift pins are properly engaged with the substrate periphery before the vacuum is released, preventing misalignment during detachment.
Solution Approach 2:
The intermediate position serves as a mediator that allows controlled vacuum release. At this position, the substrate guide surfaces are above the suction surface while the substrate holding surfaces are below, creating a transitional state that prevents sudden substrate movement or sliding that could occur with immediate vacuum release.
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 method enables safe and efficient detachment and placement of substrates by managing vacuum pressure and fluid supply, preventing substrate damage and ensuring precise positioning.
Implementation Method 1
a vacuum suction table adapted to have a substrate placed thereon
Implementation Method 2
a plurality of lift pins disposed along the outer periphery of the vacuum suction table
Data Source
AI summary
An object of the present invention is to detach a substrate from a table without damaging the substrate by lift pins.One embodiment of the present invention provides a substrate processing apparatus having a vacuum suction table adapted to have a substrate placed thereon, and a plurality of lift pins disposed along the outer periphery of the vacuum suction table. The lift pins each have a distal end portion including a substrate guide surface capable of guiding the outer peripheral end surface of the substrate, and a proximal end portion including a substrate holding surface extending from the substrate guide surface outwardly in a radial direction of the lift pin. The lift pins are stoppable in a lower end position where the substrate guide surface of each of the lift pins is disposed below a suction-holding surface of the vacuum suction table, an upper end position where the substrate holding surface of each of the lift pins is disposed above the suction-holding surface of the vacuum suction table, and an intermediate position between the lower end position and the upper end position. In the intermediate position, the substrate guide surface of each of the lift pins is disposed above the suction-holding surface of the vacuum suction table, and the substrate holding surface of each of the lift pins is disposed below the suction-holding surface of the vacuum suction table.