Semiconductor Wafer Transfer Vacuum Holding Flatness
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Solution Overview
Problem
Existing methods for transferring thin semiconductor wafers are prone to mechanical stress and damage due to the wafers' tendency to resume their original non-planar shape upon release, which is not suitable for ultra-thin wafers with a film-like nature.
Innovation Solution
Simultaneous application of surface forces by both holders using vacuum, with the first holder reducing its force only when the second holder's force is sufficient to maintain the wafer's flatness, preventing reshaping and mechanical stress during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first holder releases the semiconductor wafer by reducing its surface force, then the transfer process can proceed, but the wafer resumes its original non-planar shape causing mechanical stress and potential destruction
Solution Approach 1:
The second holder is prepared in advance by establishing negative pressure and positioning itself ready to receive the wafer before the first holder releases it. This preliminary preparation ensures that the wafer has a ready support system in place, preventing it from resuming its curved shape and avoiding mechanical stress during the transfer process.
Solution Approach 2:
The second holder acts as an intermediary that gradually takes over the support function from the first holder. By maintaining simultaneous holding by both holders during the transition, the wafer is smoothly transferred without sudden shape changes, protecting the wafer from mechanical stress while enabling efficient transfer.
2Manufacturing precision
If both holders simultaneously cause surface force on the semiconductor wafer during transfer, then the wafer remains flat throughout the process, but the system complexity increases
Solution Approach 1:
The system uses feedback from pressure sensors on both holders to monitor the holding status of the wafer. The control unit receives signals from these sensors and automatically coordinates the release timing, determining when the second holder has established sufficient holding force before the first holder reduces its surface force. This automated feedback mechanism manages the increased system complexity while ensuring precise wafer flatness maintenance throughout the transfer.
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
Ensures a safe and reliable planar transfer of semiconductor wafers by maintaining flatness throughout the process, reducing the risk of mechanical stress and damage.
Implementation Method 1
both holders simultaneously cause a surface force on opposite surfaces of the semiconductor wafer with the aid of vacuum
Implementation Method 2
the negative pressure generated by the Bernoulli effect is switched off and the semiconductor wafer is transferred to the second holder
Data Source
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AI summary
The invention relates to a method for transferring a thinned, in particular ground, semiconductor wafer (1) from a first holder (2) to a second holder (9), wherein the first holder (1) holds the semiconductor wafer (1) flat by means of a surface force (5) caused by negative pressure and releases it for transfer to the second holder (9) by reducing its surface force (5), and wherein the second holder taking over the semiconductor wafer (1) continues to hold it flat by means of a surface force (10) caused by negative pressure.To prevent the semiconductor wafer (1) from warping during its transfer, it is proposed that during the transfer of the semiconductor wafer (1) both holders (2, 9) simultaneously exert a surface force (5, 10) on opposite surfaces of the semiconductor wafer (1) using negative pressure, wherein, to release the semiconductor wafer (1), the first holder (2) only reduces its exerted surface force (5) when the surface force (10) exerted by the second holder (9) is sufficient to hold the semiconductor wafer (1) flat on the second holder (9).