Bonding Head Vacuum-Pressure Bowing for Void-Free Die Placement
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Solution Overview
Problem
Advanced packaging technologies face challenges in precise die placement on substrates due to void formation and increased overlay errors caused by die bending and shear forces during hybrid bonding, leading to improper interconnects and potential die slippage.
Innovation Solution
A bonding head design with a die chuck that utilizes vacuum and pressure actuators to hold and bow the die, minimizing jagged surfaces and air trapping, thereby reducing void formation and overlay errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the die chuck is bowed to conform the die to the substrate surface, then the die placement precision is improved, but air becomes trapped forming voids and shear forces cause die slippage
Solution Approach 1:
The die is bowed in advance during the transfer process before bonding, so that the die surface is pre-conformed to match the substrate topology. This preliminary shaping action ensures that when the die contacts the substrate, the surfaces are already aligned, preventing air trapping and void formation during the actual bonding operation.
Solution Approach 2:
The die chuck transitions from a rigid structure to a dynamically adjustable one that can change its curvature. By controlling the bowing degree of the die chuck, the system adapts the die shape to match different substrate topologies, optimizing both placement precision and bonding reliability for various geometries.
2Shape
If the die chuck is bowed to improve die conformability, then the surface contact is improved, but shear forces increase causing die stretching and slippage
Solution Approach 1:
The system controls the bowing parameter of the die chuck to optimize the balance between conformability and structural integrity. By adjusting the degree of bowing rather than maximizing it, the die achieves sufficient surface contact while keeping shear forces within safe limits that prevent die stretching or slippage.
3Manufacturing precision
If the die is held against the pins and lands, then the die positioning is improved, but the jagged surface increases void formation risk
Solution Approach 1:
The die surface is pre-shaped by the bowed die chuck to eliminate jagged edges before the die is positioned against the pins and lands. This preliminary surface preparation ensures that when positioning occurs, the die surface is already smooth and conformal, preventing air entrapment and void formation during subsequent bonding operations.
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 ensures smoother die-to-substrate contact, reducing voids and overlay errors, enhancing the reliability of die placement and interconnect formation.
Implementation Method 1
a first pressure actuator configured to provide a first vacuum within the first zone, wherein the first vacuum is sufficient to hold a die
Implementation Method 2
a second pressure actuator and configured to provide a pressure to the second zone, wherein the pressure is sufficient to bow the die while the die is being held by the first vacuum within the first zone
Data Source
AI summary
An apparatus can include a bonding head. The bonding head can include a bonding head body, a die chuck body, and lands. The bonding head body can be coupled to the die chuck. The lands can define zones. The lands and zones can be configured so that an outer zone can be under vacuum to hold a die while an inner zone is pressurized to cause the die to bow away from the bonding head. The bowed die has a relatively smoother curvature as compared to a die bent by bowing a die chuck that has pins, lands, or both. When the die contacts a substrate using the novel bonding head, the likelihood of trapping air and creating a void during a bonding operation is significantly reduced.