Wafer Unloading via Gas Flow Paths and Pneumatic Cushioning
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Solution Overview
Problem
Conventional mounting mechanisms with elevating pins require a long time to unload objects like wafers due to the need to lift them slowly while supplying exterior air to prevent depressurization, which can lead to damage as larger, thinner wafers are more prone to bending.
Innovation Solution
A method involving the use of gas flow paths on the mounting table to release vacuum-chucking, lift the object using an object lifting unit, and supply gas between the table and object during lifting, with varying lifting speeds to ensure smooth and rapid unloading without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the object is lifted quickly without supplying exterior air, then unloading time is reduced, but the object bends and may break due to depressurization
Solution Approach 1:
The patent applies preliminary action by supplying exterior air to the space between the object and mounting table before and during the lifting process. This pre-supply of air prevents depressurization from occurring during lifting, allowing the object to be raised quickly without bending or breaking. The air supply is activated in advance to ensure the object remains supported throughout the unloading process.
2Reliability
If the object is lifted slowly while supplying exterior air, then object damage is prevented, but unloading time increases significantly
Solution Approach 1:
The patent utilizes pneumatics by introducing exterior air through nozzles into the space between the object and mounting table. This pneumatic approach creates a cushion of air that supports the object during lifting, eliminating the need for slow mechanical lifting. The air pressure balances the vacuum force, allowing rapid yet safe separation of the object from the mounting surface.
3Force
If vacuum-chucking is maintained during lifting, then object adhesion is ensured, but depressurization causes bending and damage
Solution Approach 1:
The patent converts the harmful effect of vacuum adhesion (which causes bending when suddenly released) into a beneficial controlled process. By gradually supplying exterior air while maintaining vacuum-chucking, the system allows the object to lift smoothly without sudden depressurization. The vacuum force is gradually balanced by air pressure, transforming the potential harm of rapid pressure change into a controlled, damage-free lifting process.
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 approach significantly reduces unloading time and prevents damage by managing the depressurization and lifting process, allowing for quick and safe removal of wafers of varying sizes and thicknesses.
Implementation Method 1
the object is vacuum suctioned by the mounting surface and firmly adhered thereto
Implementation Method 2
supplying exterior air between the object and the mounting surface gradually
Data Source
AI summary
There is provided a method for unloading an object vacuum-chucked on a mounting table having one or more gas flow paths opened at one or more locations on the mounting table, including the steps of (a) turning off a vacuum-chucking of the object vacuum-chucked via the gas flow paths; (b) lifting the object from the mounting table by using an object lifting unit; and (C) supplying a gas between the mounting table and the object during the step (b) via at least one of the gas flow paths. Further, there is also provided a program storage medium storing therein a computer executable program for executing the unloading method.