Semiconductor Die Transfer Structure With Recessed Polymer Pillars
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor die transfer processes is achieving a balance between minimizing flyer defects (where dies break away from the holder) and ensuring reliable pickup by a pick-and-place tool, particularly when using electrostatic attraction, which is weak.
Innovation Solution
The use of organic polymer pillars with recesses in the proximal surfaces of semiconductor dies to increase retention strength on the holder, while allowing electrostatic pickup, by enhancing the contact area between the pillars and the die surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrostatic attraction is used for die pickup, then the pickup process is non-contact and clean, but the retention force is weak and insufficient to prevent flyer defects
Solution Approach 1:
The patent segments the interaction between the holder and die by introducing discrete organic polymer pillars instead of a continuous adhesive layer. These pillars are strategically positioned to provide localized retention points that enhance the electrostatic pickup force without requiring a full-surface adhesive bond, thus maintaining the non-contact pickup advantage while improving retention strength.
Solution Approach 2:
The patent applies local quality by creating recesses in the die surface at specific locations where pillars will contact. This localized modification concentrates the retention force at critical points rather than distributing it uniformly, enhancing the effectiveness of the weak electrostatic attraction precisely where needed to prevent flyer defects during transfer.
2Reliability
If stronger adhesion is used to prevent flyer defects, then die retention improves, but reliable pickup by electrostatic attraction becomes difficult
Solution Approach 1:
The patent creates a dynamic retention system where the organic polymer pillars provide adjustable adhesion strength. The pillars can be engineered with specific heights, diameters, and material properties that allow the retention force to be optimized for each stage of the process: strong enough to hold dies during transfer, but weak enough to release when electrostatic pickup occurs. This dynamic balance resolves the contradiction between retention and pickup reliability.
Solution Approach 2:
The patent employs parameter changes by modifying the physical and chemical properties of the organic polymer pillars (material composition, pillar height, diameter, spacing, and surface energy) to tune the retention force. By adjusting these parameters, the system achieves the optimal balance where dies are securely held during transfer (preventing flyers) but can be reliably picked up by electrostatic attraction when needed.
3Strength
If the contact area between pillars and die surfaces is increased, then retention strength improves, but the structure complexity increases
Solution Approach 1:
The patent increases the contact area between pillars and die surfaces by utilizing the vertical dimension through recesses. Instead of expanding the horizontal footprint of pillars (which would increase device complexity), the pillars extend into recesses etched into the die surface. This vertical engagement significantly increases the contact area and retention strength while maintaining a compact horizontal structure, effectively resolving the contradiction between strength and complexity.
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
This approach reduces flyer defects and increases the yield of semiconductor die transfer by providing a tailored retention force that supports reliable pickup, optimizing the balance between adhesion and electrostatic attraction.
Implementation Method 1
The use of organic polymer pillars with recesses in the proximal surfaces of semiconductor dies to increase retention strength on the holder, while allowing electrostatic pickup, by enhancing the contact area between the pillars and the die surfaces.
Implementation Method 2
achieving a balance between minimizing flyer defects (where dies break away from the holder) and ensuring reliable pickup by a pick-and-place tool, particularly when using electrostatic attraction, which is weak.
Data Source
AI summary
An assembly for semiconductor die transfer includes a carrier wafer, semiconductor dies oriented with proximal surfaces thereof facing the carrier wafer, and pillars comprising an organic polymer material supporting the semiconductor dies on the carrier wafer. The pillars have distal ends filling recesses in the proximal surfaces of the semiconductor dies. A semiconductor die of the semiconductor die transfer structure is picked up using a pick-and-place tool. To fabricate the structure, a dielectric layer is disposed on the proximal surfaces of the semiconductor dies, and openings are etched in the dielectric layer and the etching is continued into the proximal surfaces of the semiconductor dies to form the recesses therein. The dielectric layer is bonded to the carrier wafer using the organic polymer material which also fills the openings in the dielectric layer and the recesses in the proximal surfaces of the semiconductor dies. The dielectric layer is removed.