Semiconductor Package Wire Isolation for Electromigration Reliability
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Solution Overview
Problem
High routing density in semiconductor packaging substrates leads to short circuits between adjacent wires due to electromigration under highly accelerated stress test conditions, resulting in packaging failure.
Innovation Solution
A semiconductor package structure is formed by creating a substrate with mutually independent conductive wires, oxidizing the side walls of each wire to form a barrier layer, and filling trenches between the wires with a solder mask, which changes the migration path of conductive particles and reduces the probability of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If routing density is increased to improve substrate integration, then area utilization is improved, but electromigration causes short circuits between adjacent wires reducing reliability
Solution Approach 1:
The conductive wires are segmented into mutually independent sections by introducing trenches between adjacent wires. This segmentation prevents electromigration-induced short circuits by physically isolating adjacent conductive paths, allowing higher routing density while maintaining reliability.
Solution Approach 2:
A solder mask material is introduced as an intermediary substance filling the trenches between adjacent conductive wires. This intermediary layer prevents direct contact and electromigration between wires, enabling closer wire spacing without compromising packaging reliability.
2Area of stationary object
If wire width is reduced to increase routing density, then area utilization is improved, but manufacturing precision requirements increase
Solution Approach 1:
The structure transitions from uniform continuous wires to localized segmented conductive sections separated by trenches. This local modification allows standard manufacturing processes to be used while achieving effective wire isolation, reducing precision requirements for wire width control.
3Reliability
If trench depth is increased to improve wire isolation, then reliability is improved, but device complexity increases
Solution Approach 1:
The trench filling uses solder mask material that is homogeneously applied across all trenches. This uniform approach simplifies the manufacturing process and reduces device complexity while maintaining effective isolation and reliability improvement.
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 barrier layer prevents electromigration, enhancing the reliability of the packaging structure by reducing the likelihood of short circuits and improving performance reliability.
Implementation Method 1
side walls of each of the conductive wires are oxidized to form a barrier layer
Implementation Method 2
a solder mask is formed at least filling the trench
Data Source
AI summary
A method for forming the packaging structure includes: providing a substrate; forming a plurality of mutually independent conductive wires on the substrate, wherein a trench is provided between adjacent conductive wires; oxidizing side walls of each of the conductive wires to form a barrier layer; and forming a solder mask at least filling the trench.