Wafer Bonding Pressure Control for Uniform Bonding Wave Velocity
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Solution Overview
Problem
Existing wafer bonding technologies face challenges in achieving uniform bonding wave velocity, leading to stress and strain variations that cause unfavorable patterning shape changes and distortions in bonded wafer pairs.
Innovation Solution
A wafer bonding system that monitors the distance between wafers in real time using distance sensors to control vacuum pressures on a wafer chuck, modulating the bonding wave velocity to ensure uniform propagation and reduce distortions by adjusting vacuum zone pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wafer bonding methods are used, then bonding can be achieved, but uniform bonding wave velocity cannot be maintained, leading to stress and strain variations
Solution Approach 1:
The system dynamically adjusts vacuum pressure in real-time during the bonding process. Multiple vacuum zones with independently controllable pressures are used to modulate the bonding wave velocity as it propagates across the wafer surfaces, ensuring uniform velocity despite variations in wafer properties or environmental conditions
Solution Approach 2:
The invention changes the vacuum pressure parameter across different spatial zones and time periods during bonding. By varying pressure levels in specific vacuum zones at specific times, the system controls the propagation velocity of the bonding wave to maintain uniformity throughout the bonding process
2Shape
If bonding wave velocity is not uniformly controlled, then bonding process is simpler, but stress and strain variations cause unfavorable patterning shape changes and distortions
Solution Approach 1:
The bonding chamber is divided into multiple vacuum zones with independently controllable pressures. This segmentation allows different regions of the wafer to experience optimized vacuum conditions, enabling precise control of bonding wave velocity in each zone to prevent distortions and maintain patterning accuracy
Solution Approach 2:
The system incorporates sensors to monitor bonding wave propagation in real-time and uses this feedback to dynamically adjust vacuum pressure in various zones. This closed-loop control ensures that bonding wave velocity remains uniform, preventing stress and strain variations that would cause shape changes
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
The system achieves a more uniform bonding wave velocity, reducing stress and strain variations, thereby minimizing distortions in bonded wafers and improving the quality of the bonding process.
Implementation Method 1
modulating the bonding wave velocity to ensure uniform propagation and reduce distortions by adjusting vacuum zone pressures
Implementation Method 2
monitors the distance between wafers in real time using distance sensors
Data Source
AI summary
A method includes mounting a first wafer on a first wafer chuck and mounting a second wafer on a second wafer chuck. The second wafer is brought into physical contact with the first wafer. A relative distance between the first wafer and the second wafer is monitored using a distance sensor. A pressure of a vacuum zone on the second wafer chuck is controlled using feedback from the distance sensor. The bonded first wafer and second wafer are removed from the first wafer chuck.