Embedded Wire Repair for PCB Impedance Control
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Solution Overview
Problem
Conventional methods for repairing printed circuit board (PCB) connections, such as yellow wire rework, often degrade the characteristic impedance and electrical performance, are not cost-effective, and are limited to lab-use scenarios, as they do not address errors at the intended physical layers.
Innovation Solution
The implementation of an embedded wire repair method within the PCB stack, where a repair wire layer with isolated conductors or meshes is integrated during manufacturing, allowing for controlled impedance and avoiding cross-talk, using materials like copper or aluminum, and routing individual wires to plated through holes for precise connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If conventional yellow wire rework is used to repair PCB connections, then repair can be performed on existing hardware, but the characteristic impedance and electrical performance are substantially degraded
Solution Approach 1:
The patent moves the repair wire from the surface layer (2D plane) to an embedded layer within the PCB stack (3D space). This dimensional change allows the repair wire to be surrounded by reference planes on both sides, maintaining controlled impedance and electrical performance while enabling repair functionality.
Solution Approach 2:
The repair wire is nested within the PCB structure itself, embedded between reference planes in the PCB stack. This nesting allows the repair wire to be integrated into the existing PCB architecture, maintaining the characteristic impedance and electrical performance of the original design while providing repair capability.
2Ease of repair
If surface layer wire repair is performed, then circuit connections can be corrected, but the repair is not cost effective and efficient for production
Solution Approach 1:
The repair wire is embedded and prepared during the initial PCB manufacturing process, before the board is assembled and deployed. This preliminary action allows repair connections to be established efficiently later by simply drilling through-holes and making connections to the pre-positioned embedded wire, avoiding costly and time-consuming surface rework operations.
3Ease of operation
If repair wires are placed on the surface layer, then connections can be made, but cross-talk and impedance control are compromised
Solution Approach 1:
Reference planes are introduced as intermediary structures that surround and isolate the embedded repair wire. These reference planes act as shields that prevent electromagnetic interference and cross-talk between the repair wire and other PCB traces, while also providing impedance control through their geometric relationship to the repair wire.
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 approach enables efficient and cost-effective embedded wire repair that maintains controlled impedance and enhances electrical performance by isolating repair wires from other layers, allowing for board repairs post-component mounting without additional surface modifications.
Implementation Method 1
an appropriate plated through hole (PTH) is drilled to form the repair connection using the repair wire layer
Data Source
AI summary
Methods and structures are provided for implementing embedded wire repair for printed circuit board (PCB) constructs. A repair wire layer is provided within the PCB stack with reference planes on opposite sides of the repair wire layer. When a repair connection is required, an appropriate plated through hole (PTH) is drilled to form the repair connection using the repair wire layer.