Metal-Pillar Die Assembly to Contain Bonding Material
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Solution Overview
Problem
In the assembly of electronic chips or dies in flat integrated circuits with no leads, the bonding material often rises up onto the sides of the die, which can lead to reliability issues and increased risk of failure.
Innovation Solution
The use of metal pillars extending from the die surface, with heights ranging from 20 μm to 150 μm, that are designed to interact with a bonding material, such as epoxy glue or solder paste, to prevent the material from rising onto the sides during assembly, thereby containing it under the die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the die is pressed against the package during fastening to adhere the bonding material, then the bonding material adheres to the die, but the bonding material rises up onto the sides of the die
Solution Approach 1:
Metal pillars are introduced as intermediary structures between the die and the bonding material. These pillars extend from the die surface into the bonding material, serving as physical barriers that prevent the bonding material from rising onto the lateral edges of the die while still allowing adequate bonding adhesion.
Solution Approach 2:
The solution adds a vertical dimension element (metal pillars extending upward from the die surface) to control the horizontal spread of bonding material. By introducing structures that protrude in the vertical direction, the bonding material is contained within a defined vertical envelope and prevented from flowing laterally onto the die sides.
2Object-affected harmful factors
If metal pillars are added to prevent bonding material from rising, then bonding material containment is improved, but device structure becomes more complex
Solution Approach 1:
The metal pillars have optimized dimensional parameters - heights of 20-150 μm and appropriate spacing - that provide effective bonding material containment while minimizing structural complexity. By carefully controlling these parameters, the pillars achieve the desired containment function without excessive complexity.
Solution Approach 2:
Metal pillars are strategically positioned at specific locations on the die surface where bonding material containment is most needed, rather than uniformly covering the entire surface. This localized approach provides effective containment while minimizing the overall structural complexity and material usage.
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 effectively prevents the bonding material from rising onto the lateral edges of the die, reducing the risk of failure and allowing for a more reliable assembly process, while also enabling the assembly of multiple dies with reduced thickness and increased longevity of the electronic device.
Implementation Method 1
bringing the die and the support together so that the pillars crush the bonding material
Implementation Method 2
The forming of the metal pillars is performed by electrolytic growth
Implementation Method 3
the assembly method comprises a step of annealing the bonding material at the end of the step of bringing the die and the support together
Data Source
AI summary
The present disclosure relates to a die comprising metal pillars extending from a surface of the die, the height of each pillar being substantially equal to or greater than 20 μm, the pillars being intended to raise the die when fastening the die by means of a bonding material on a surface of a support. The metal pillars being inserted into the bonding material at which point the bonding material is annealed to be cured and hardened solidifying the bonding material to couple the die to the surface of the support.