Semiconductor Package Metal Pad Corrosion Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chip-on-board (COB) semiconductor packages face challenges in providing saline water corrosion resistance and reducing fabrication costs, particularly with the use of copper layers that require expensive plating processes and are prone to oxidation.
Innovation Solution
The semiconductor package incorporates a metal pad with a saline water corrosion-resistant surface treated with chromium (Cr) and/or zirconium (Zr) on an aluminum, stainless steel, or brass pad, eliminating the need for expensive plating processes and enhancing corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper layers are used in COB-type packages, then electrical conductivity is improved, but corrosion resistance deteriorates due to oxidation and requirement for expensive plating
Solution Approach 1:
The patent extracts the copper layer from the package structure and replaces it with aluminum pads that have corrosion-resistant surface treatments. This eliminates the need for expensive plating processes while maintaining electrical conductivity and improving corrosion resistance in saline environments.
Solution Approach 2:
The patent changes the material parameter from copper to aluminum, and applies surface treatment parameters (chromium or zirconium coating) to the aluminum pads. This material substitution fundamentally alters the corrosion behavior while reducing manufacturing complexity and cost.
2Reliability
If copper layers are plated with expensive materials (Au, Ni/Pd, Ni/Au), then corrosion resistance is improved, but fabrication cost increases
Solution Approach 1:
The patent uses inexpensive aluminum as the base material and applies thin corrosion-resistant surface treatments instead of expensive precious metal plating. This approach achieves adequate corrosion protection without the high costs associated with gold, nickel, or palladium plating processes.
Solution Approach 2:
The patent replicates the corrosion protection function previously achieved by expensive metal plating, but uses alternative methods (chromium or zirconium surface treatment on aluminum) that are less costly and equally effective for saline water resistance.
3Ease of operation
If through holes are created in the core, then wire bonding capability is improved, but structural integrity may deteriorate
Solution Approach 1:
The patent creates through-holes only in specific locations where wire bonding is required, rather than uniformly throughout the core. The holes are strategically positioned to provide electrical connectivity while minimizing impact on overall structural integrity of the package substrate.
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 solution provides effective saline water corrosion resistance and reduces fabrication costs by eliminating the need for expensive plating processes, while maintaining electrical connectivity through bonding wires and solder bumps, thus improving the durability and reliability of the semiconductor package.
Implementation Method 1
The saline water corrosion resistant surface may include a surface film including chromium (Cr) and/or zirconium (Zr) on the metal pad
Data Source
AI summary
Package substrates, semiconductor packages including the package substrates, and methods for fabricating the semiconductor packages are provided. A package substrate may include a core including a first surface on which a semiconductor chip is disposed and a second surface opposite the first surface. The package substrate may also include a metal pad on the second surface of the core. The metal pad may include a saline water corrosion resistant surface.