Wiring Board Opening Structure for Terminal Alignment Reliability
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Solution Overview
Problem
Conventional wiring boards experience misalignment issues during the formation of connection terminals, leading to deteriorated connection reliability due to conduction failures and short circuits as the boards miniaturize.
Innovation Solution
A wiring board design featuring a unique opening structure within insulating and solder resist layers, where the second opening's lower end matches the first opening's upper end diameter, and the third opening's lower end is larger, with a specific angle configuration, formed using laser light irradiation to reduce misalignment, and a connection terminal structure with a titanium adhesion layer and copper pad to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wiring board manufacturing processes are used with standard opening structures, then the manufacturing process is simple, but misalignment occurs in growth mask and solder resist layer openings leading to deteriorated connection reliability
Solution Approach 1:
The opening structure is divided into three distinct segments: a first opening through the first insulating layer, a second opening through the second insulating layer with a lower end connected to the upper end of the first opening, and a third opening through the second insulating layer with a lower end connected to the upper end of the second opening. This segmentation allows each opening to be optimized for its specific function, preventing misalignment between different layers while maintaining manufacturing feasibility.
Solution Approach 2:
Different portions of the opening structure have different diameters tailored to their specific requirements. The first opening has a diameter equal to the diameter of the lower end of the second opening, while the third opening has a larger diameter at its lower end than the upper end of the second opening. This local variation in dimensions ensures proper alignment and connection reliability without requiring complex manufacturing processes throughout the entire structure.
2Volume of moving object
If the wiring board is miniaturized to reduce size, then the device becomes more compact, but misalignment in growth mask and solder resist layer openings increases leading to conduction failures and short circuits
Solution Approach 1:
By segmenting the opening structure into three distinct openings through different insulating layers, each opening can be precisely controlled and aligned independently. The connection between the lower end of one opening and the upper end of the next opening ensures continuous alignment, preventing misalignment issues that would otherwise occur during miniaturization.
Solution Approach 2:
The three openings are nested vertically through different insulating layers, with the lower end of each opening connected to the upper end of the opening below it. This nested configuration allows precise alignment to be maintained throughout the vertical stack, enabling miniaturization without sacrificing manufacturing precision.
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 design effectively reduces misalignment and improves connection reliability by minimizing conduction failures and short circuits, while the adhesion and barrier layers prevent plating solution ingress and copper migration, maintaining high thermal resistance.
Implementation Method 1
formed using laser light irradiation to reduce misalignment
Implementation Method 2
a connection terminal structure with a titanium adhesion layer and copper pad to enhance reliability
Implementation Method 3
the adhesion and barrier layers prevent plating solution ingress and copper migration
Implementation Method 4
the connection terminals are surface-treated by electroless plating
Data Source
AI summary
A wiring board includes a first insulating layer provided on an interconnect layer, a second insulating layer provided on the first insulating layer, a first opening formed in the first insulating layer and reaching the interconnect layer, a second opening formed in the second insulating layer and having a lower end connected to an upper end of the first opening, a third opening formed in the second insulating layer and having a lower end connected to an upper end of the second opening, and a connection terminal formed inside the first, second, and the third openings, and making contact with an upper surface of the interconnect layer. The lower end diameter of the second opening is equal to the upper end diameter of the first opening, and the lower end diameter of the third opening is larger than the upper end diameter of the second opening.