PCB Tap Terminal Segmentation for Short Circuit Prevention
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Solution Overview
Problem
As semiconductor devices become more integrated, the increased number of tap terminals and decreased pitch between them lead to a higher risk of short circuits due to external physical impacts, particularly when plating wires are damaged, as they can connect adjacent tap terminals electrically, compromising the reliability of printed circuit boards (PCBs) for semiconductor modules.
Innovation Solution
The design of printed circuit boards (PCBs) for semiconductor modules incorporates tap terminals with recessed portions and plating wires that extend from the terminals, where the plating wires have a smaller line width than the terminals, and are positioned outside a circle defined by the adjacent terminal's protrusion, preventing electrical connection even if the plating wire is damaged, thus enhancing reliability by avoiding short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch between adjacent tap terminals is decreased to increase integration, then the number of terminals per unit area increases, but the risk of short circuits due to external physical impacts increases
Solution Approach 1:
The tap terminal is segmented into a main body portion and a protrusion portion, where the protrusion extends beyond the main body. This segmentation allows the protrusion to serve as an isolated electrical contact point that maintains electrical connection even when the main body is subjected to external impacts, thereby preventing short circuits between adjacent terminals while maintaining high integration density.
Solution Approach 2:
The protrusion is pre-formed as an extended structure from the main body of the tap terminal before any external impacts occur. This preliminary structural configuration ensures that the protrusion is already positioned to make electrical contact with the socket, providing a pre-established electrical path that remains functional even under external physical stress, thus preventing short circuits.
2Ease of manufacture
If plating wires are used to form tap terminals through electroplating, then terminal formation is achieved, but thin plating wires may remain connected to terminal end portions creating short circuit risks
Solution Approach 1:
The harmful plating wire residue is extracted or removed from the terminal structure. The protrusion is designed such that any remaining thin plating wire is positioned outside the circular region defined by the protrusion's geometry, effectively extracting the potential short circuit path from the critical electrical connection area and isolating it from causing harmful electrical connections between adjacent terminals.
Solution Approach 2:
The thin plating wire residue, which could potentially cause short circuits, is repositioned or configured to lie outside the critical circular region defined by the protrusion. This converts the potential harm into a benign configuration where the plating wire residue no longer poses a short circuit risk, as it is positioned in a location where it cannot create harmful electrical connections between adjacent terminals.
3Reliability
If various shapes for tap terminals are developed to prevent short circuits, then short circuit prevention improves, but device complexity increases
Solution Approach 1:
Instead of varying the overall shape of all tap terminals, only the local region at the end of each terminal is modified to include a protrusion. This localized structural change provides the necessary short circuit prevention functionality while keeping the rest of the terminal structure simple and uniform, thereby minimizing device complexity while achieving improved reliability.
Solution Approach 2:
The tap terminal structure incorporates an asymmetric protrusion that extends beyond the main body in a specific direction. This asymmetric configuration provides effective short circuit prevention by positioning the electrical contact point away from the main terminal body, while the asymmetry is applied consistently to all terminals in the same manner, avoiding the complexity of varying shapes and maintaining manufacturing simplicity.
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 prevents short circuits between adjacent tap terminals, even when the plating wires are damaged, thereby increasing the reliability and durability of the PCBs for semiconductor modules by ensuring that the tap terminals remain electrically isolated.
Implementation Method 1
Because the tap terminal is formed by an electroplating process, a plating wire having a thin width may remain to be connected to an end portion of the tap terminal.
Data Source
AI summary
A printed circuit board (PCB) includes a substrate body including a circuit wiring layer; tap terminals provided at a surface of the substrate body and in a peripheral region of the substrate body and electrically connected to the circuit wiring layer; and plating wires corresponding to respective tap terminals, each plating wire extending from an end portion of its respective tap terminal toward an edge of the substrate body and having a line width smaller than a line width of the tap terminal. For at least a first tap terminal, the tap terminal shares an edge with an edge of its respective plating wire. A second tap terminal adjacent the first tap terminal is positioned outside a circle having a radius that equals a length of the plating wire and having a center at a point along the shared edge where the plating wire and first tap terminal connect.