Wafer Debonding with Circular Blades for Thin-Wafer Integrity
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Solution Overview
Problem
Conventional wafer debonding systems face inefficiencies and high defect rates, particularly with thin wafers, due to mechanical or chemical methods that often result in breakages and edge defects, while double-sided systems risk wafer breakage with excessive force.
Innovation Solution
A wafer debonding system using a pair of circular plate blades with controlled insertion and rotation, combined with adjustable pulling forces and optical inspection, minimizes wafer breakage by applying unbalanced torques and precise control of insertion depth and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical or chemical methods are used to separate wafer stacks, then separation can be achieved, but wafer breakages and edge defects occur frequently
Solution Approach 1:
The debonding process is segmented into multiple phases: initial insertion phase, propagation phase, and completion phase. The blade inserts at one location and propagates the debond front around the wafer circumference, separating the wafer stack in a controlled manner rather than applying force all at once, thereby reducing wafer breakage while maintaining efficiency
Solution Approach 2:
The system dynamically adjusts blade insertion depth, insertion speed, and pulling force based on real-time feedback from force sensors and optical inspection systems. The blade velocity and insertion depth are continuously optimized during the debonding process to maintain wafer integrity while achieving efficient separation
2Manufacturing precision
If a flat blade is repeatedly inserted and retracted at the bevel region while the wafer rotates 360°, then debonding can be performed, but large edge defects occur at the opposite side of the flat blade insertion point
Solution Approach 1:
The system uses an asymmetric blade geometry with a rounded leading edge and a tapered trailing edge, inserted at an optimized angle (e.g., 45 degrees) relative to the wafer surface. This asymmetric configuration allows the blade to propagate the debond front uniformly around the wafer circumference, eliminating the edge defects that occur with symmetric flat blade insertion at the bevel region
Solution Approach 2:
Instead of inserting the blade only at the bevel region (one-dimensional approach), the system inserts the blade at an optimized angle and depth to create a three-dimensional debonding path that propagates uniformly around the wafer. This multi-dimensional approach ensures consistent edge quality at all locations, including the opposite side of insertion
3Reliability
If double sided debonding systems are used, then the risk of defects near wafer edges is reduced, but larger pull force is required which may result in wafer breakages
Solution Approach 1:
The system performs preliminary actions by first inserting the blade to initiate the debond front, then gradually propagating it around the wafer circumference before applying full pulling force. This preliminary blade insertion creates a controlled separation path, allowing the wafer to be separated with minimal pull force and reducing the risk of wafer breakage while maintaining low edge defect rates
4Productivity
If thin wafers are subjected to conventional debonding processes, then separation can be achieved, but wafer failure occurs frequently
Solution Approach 1:
The system dynamically changes critical parameters including blade insertion depth, blade velocity, and pulling force based on wafer thickness and material properties. For thin wafers, the blade insertion depth is limited to prevent excessive bending, and the pulling force is optimized to achieve separation without causing wafer failure, thereby maintaining both productivity and wafer strength
Data Source
AI summary
An apparatus and method for debonding a pair of bonded wafers are disclosed herein. In some embodiments, the debonding apparatus, comprises: a wafer chuck having a preset maximum lateral dimension and configured to rotate the pair of bonded wafers attached to a top surface of the wafer chuck, a pair of circular plate separating blades including a first separating blade and a second separating blade arranged diametrically opposite to each other at edges of the pair of bonded wafers, wherein the first and the second separating blades are inserted between a first and a second wafers of the pair of bonded wafers, and at least two pulling heads configured to pull the second wafer upwardly so as to debond the second wafer from the first wafer.