Wafer Chuck Movable Pads for Warped Wafer Vacuum Sealing
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Solution Overview
Problem
Scanning acoustic microscopes face challenges in inspecting warped bonded wafer pairs due to insufficient vacuum seals, which can lead to damage during inspection, as prior art wafer chucks assume flatness and may not accommodate significant warpage in contemporary semiconductor products.
Innovation Solution
A wafer chuck with multiple vacuum zones and suction cups that apply suction through channels and vacuum holes to pull warped wafers flat, ensuring a secure seal and maintaining flatness for inspection, accommodating various wafer sizes and shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a prior art wafer chuck is used that assumes flatness to form a vacuum seal, then the vacuum seal is sufficient for flat wafers, but the chuck cannot accommodate warped wafers with significant warpage
Solution Approach 1:
The wafer chuck incorporates movable pads that can dynamically adjust their position and height to conform to the warped surface of the wafer. These pads are capable of moving vertically and horizontally to maintain contact with the wafer surface regardless of warpage, enabling reliable vacuum seal formation on non-flat surfaces
Solution Approach 2:
The system changes the physical parameters of the chuck surface by introducing movable pads with adjustable height and position. This allows the contact surface to adapt to varying wafer warpage conditions, transforming a static rigid surface into a dynamic adaptive surface that maintains seal integrity
2Reliability
If mechanical pressing is applied to flatten warped wafers to form a vacuum seal, then the vacuum seal can be formed, but the wafer may be damaged
Solution Approach 1:
The wafer chuck uses flexible movable pads that can deform and conform to the warped wafer surface without applying excessive localized stress. These pads act as compliant interfaces that adapt to the wafer's shape rather than forcing the wafer into a flat configuration, preventing damage while maintaining seal integrity
Solution Approach 2:
The system employs pneumatic or hydraulic actuators to control the movement and positioning of the pads. By using fluid pressure to adjust pad positions, the system can gently apply distributed force to maintain contact with warped surfaces without creating high-stress concentration points that would damage the wafer
3Reliability
If the wafer is pressed down by hand or mechanical mechanism to form a seal, then the vacuum seal can be achieved, but the process is complex and potentially damaging
Solution Approach 1:
The movable pads are designed to automatically adjust and self-align with the wafer surface through spring mechanisms or gravity-assisted positioning. The pads self-regulate their contact pressure and position based on the wafer's warpage, eliminating the need for complex external pressing mechanisms or manual intervention
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 solution effectively secures and flattens warped wafers for scanning acoustic microscope inspection, preventing damage and ensuring a reliable vacuum seal, even for wafers with significant warpage, thereby improving inspection accuracy and safety.
Implementation Method 1
A wafer chuck with multiple vacuum zones and suction cups that apply suction through channels and vacuum holes to pull warped wafers flat
Data Source
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AI summary
A wafer chuck includes a support structure having a first side structurally configured to support a wafer, and a vacuum zone formed on the first side of the support structure. The vacuum zone may be at least partially bounded by a ring extending from a recessed surface of the first side of the support structure. The wafer chuck further includes a plurality of suction cups disposed in the vacuum zone, where one or more of the plurality of suction cups is coupled with a channel extending through the support structure. One or more vacuums are in fluid communication with the channel, where a vacuum is structurally configured to provide suction through the channel.