PCB Aluminum Pattern and Passivation Layer for Bonding Reliability
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Solution Overview
Problem
Current printed circuit boards (PCBs) and semiconductor packages face challenges in reducing process costs and improving bonding process reliability due to the need for smaller and more densely packed connection terminals, which complicates surface treatment and increases manufacturing complexity.
Innovation Solution
A PCB design featuring an insulating layer with copper and aluminum patterns, along with organic passivation layers, is implemented to reduce costs and enhance bonding reliability. The PCB includes a method of manufacturing that involves forming conductive patterns, passivation layers, and solder resist layers to prevent diffusion and ensure reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If connection terminals are made smaller and more densely packed to reduce PCB area, then the total area of the PCB is reduced, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent divides the connection terminal structure into multiple segments: a base conductive pattern layer, an aluminum pattern layer, and a passivation layer. This segmentation allows each layer to be optimized independently, simplifying the surface treatment process while maintaining compact terminal design
Solution Approach 2:
The patent uses composite material structure combining copper (in the conductive pattern), aluminum (in the aluminum pattern), and organic passivation materials. This composite approach enables smaller terminal sizes with improved manufacturability, as each material contributes its optimal properties to the overall structure
2Ease of manufacture
If aluminum pattern is applied to conductive patterns to reduce costs, then manufacturing costs are reduced, but oxidation and diffusion issues may arise
Solution Approach 1:
The patent introduces an organic passivation layer as an intermediary between the aluminum pattern and the external environment. This passivation layer prevents oxidation of the aluminum and diffusion into the conductive pattern, thereby maintaining bonding reliability while keeping manufacturing costs low
Solution Approach 2:
The patent uses aluminum as a cost-effective surface treatment material instead of expensive traditional materials. The aluminum pattern provides the necessary functionality at lower cost, with the passivation layer protecting it from degradation
3Reliability
If passivation layers are added to prevent diffusion and oxidation, then bonding reliability is improved, but the number of process steps increases
Solution Approach 1:
The patent combines the passivation function with the surface treatment process itself, integrating oxidation prevention and diffusion barrier properties into the aluminum pattern structure. This merging reduces the number of separate process steps while maintaining improved bonding reliability
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 solution effectively reduces manufacturing costs and improves bonding process reliability by using aluminum for surface treatment, allowing for larger spaces between pads and preventing oxidation, thus enhancing the electrical connection reliability.
Implementation Method 1
a first passivation layer that covers at least a portion of sides of the first conductive pattern and that prevents diffusion into the first conductive pattern
Implementation Method 2
an aluminum pattern that covers at least a portion of an upper surface of the first conductive pattern
Data Source
AI summary
A printed circuit board (PCB) includes an insulating layer with an upper surface and a lower surface opposite to the upper surface; a first conductive pattern on the upper surface of the insulating layer; a second conductive pattern on the lower surface of the insulating layer; an aluminum pattern that covers at least a portion of an upper surface of the first conductive pattern; and a first passivation layer that covers at least a portion of sides of the first conductive pattern and that prevents diffusion into the first conductive pattern.