Semiconductor Package Bonding Pads With Concavo-Convex Wire Anchoring
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Solution Overview
Problem
The structural stability of bonding wires in semiconductor packages is low due to copper bonding pads, leading to decreased yield in the wire bonding process during the manufacturing of fan out packages.
Innovation Solution
A semiconductor package design featuring a concavo-convex pattern on bonding pads, where the vertical conductive wires are bonded, increasing the contact area and providing an anchoring effect by filling the grooves with metal, thereby enhancing adhesion and structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper bonding pads are used, then electrical conductivity is improved, but structural stability of bonding wires decreases
Solution Approach 1:
The bonding pad surface is modified with a concavo-convex pattern that creates localized regions of different properties. The convex portions provide structural support while the concave portions enhance adhesion through mechanical interlocking with the bonding wire, allowing the bonding pad to simultaneously achieve good electrical conductivity and structural stability.
Solution Approach 2:
The concavo-convex pattern introduces curved surfaces instead of a flat bonding pad surface. The convex portions act as raised structures that provide mechanical strength, while the concave portions create depression zones that enhance wire adhesion through increased surface area and mechanical interlocking, thereby improving structural stability while maintaining conductivity.
2Ease of manufacture
If conventional flat bonding pads are used, then manufacturing process is simple, but adhesion between bonding pads and vertical conductive wires is insufficient
Solution Approach 1:
The bonding pad surface is transformed from flat to concavo-convex by forming convex portions and concave portions. This curvature modification increases the surface area available for bonding and creates mechanical interlocking features that significantly enhance adhesion strength between the bonding pad and vertical conductive wires.
Solution Approach 2:
The concavo-convex pattern creates a porous-like surface structure with recessed regions that can accommodate bonding wire material. This increased surface complexity provides more bonding interfaces and mechanical interlocking points, thereby enhancing adhesion strength while remaining compatible with standard manufacturing processes.
3Stability of the object's composition
If bonding pad surface area is increased to improve adhesion, then manufacturing complexity increases, but structural stability improves
Solution Approach 1:
Instead of significantly increasing the overall bonding pad area, the invention modifies the surface topology by creating convex and concave portions. This approach increases the effective bonding surface area through three-dimensional surface features rather than expanding the two-dimensional footprint, thereby improving structural stability without substantially increasing device complexity.
Solution Approach 2:
The concavo-convex pattern creates localized variations in surface properties without requiring a complete redesign of the bonding pad structure. By concentrating adhesion-enhancing features in specific local regions (convex and concave portions), the invention improves structural stability while maintaining overall structural simplicity and minimizing manufacturing 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
The enhanced adhesion between bonding pads and vertical conductive wires improves the structural stability and yield of the wire bonding process, addressing the low stability issues associated with copper bonding pads.
Implementation Method 1
each of the plurality of bonding pads having a concavo-convex pattern on a surface of the bonding pad, wherein the plurality of vertical conductive wires are bonded to the concavo-convex patterns of the plurality of bonding pads, respectively
Implementation Method 2
The enhanced adhesion between bonding pads and vertical conductive wires improves the structural stability
Data Source
AI summary
A semiconductor package includes a first redistribution wiring layer having a first region and a second region surrounding the first region, a semiconductor chip disposed on the first region of the first redistribution wiring layer, a sealing member covering the semiconductor chip on the first redistribution wiring layer, vertical conductive wires penetrating the sealing member on the second region of the first redistribution wiring layer, a second redistribution wiring layer disposed on the sealing member and including second redistribution wirings electrically connected to the vertical conductive wires, and bonding pads provided on an upper surface of the first redistribution wiring layer or a lower surface of the second redistribution wiring layer, each bonding pad having a concavo-convex pattern on an upper surface of the bonding pad. The vertical conductive wires are bonded to the concavo-convex patterns of the bonding pads, respectively.