Micro-castellated Interposer for Reliable Circuit Rework

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Solution Overview

Problem

Existing methods for repairing and reworking high-speed circuitry in electronic devices are costly, prone to human error, and not suitable for small geometry parts, as they require skilled labor, are expensive, and introduce variability in electrical integrity, especially when dealing with smaller components and higher speeds.

Innovation Solution

A micro-castellated interposer that allows for automated assembly and accommodates disparate parts and geometries, forming robust solder joints with optimized pad and castellation geometries to maintain reliability and cost-effectiveness, utilizing standard manufacturing techniques and materials that account for thermal expansion differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If manual rework methods (dead bugging, cut and jumpering) are used to repair circuitry, then repair capability is achieved, but human error increases and reliability decreases

Engineering Contradiction:

Improverepair capabilityVSAvoidelectrical integrity

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The patent introduces a micro-castellated interposer as an intermediary component between the parent circuit board and replacement components. This interposer provides standardized castellated pads that align with existing board traces, enabling automated SMT assembly while maintaining reliable electrical connections. The interposer acts as a mediator that bridges manual repair needs with automated manufacturing processes, eliminating human error in trace routing while preserving repair capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If custom hybrid parts are used to incorporate wiring changes, then electrical functionality is achieved, but cost increases and manufacturing complexity increases

Engineering Contradiction:

Improveelectrical functionalityVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the circuit board modification into a separate, removable micro-castellated interposer component. This interposer contains the wiring changes and component mounting areas, allowing it to be manufactured separately using standard PCB processes. The segmentation enables the interposer to be produced in volume using automated SMT lines, reducing both cost and manufacturing complexity compared to custom hybrid parts while maintaining electrical adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The micro-castellated interposer is designed with universal castellated pad patterns that can accommodate various component types and wiring configurations. The standardized interposer design can be used across multiple parent board revisions and component variants, providing multi-functionality that reduces manufacturing complexity and cost while maintaining the ability to implement electrical functionality changes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of repair

If manual rework with magnification aids is used for smaller geometry parts, then part replacement is achieved, but skill requirements increase and cost increases

Engineering Contradiction:

Improvepart replacement capabilityVSAvoidskill requirements

Core Design Contradiction:

Ease of repairVSEase of manufacture

Solution Approach 1:

The patent replaces manual mechanical rework processes (soldering, wire wrapping, component handling with magnification) with automated SMT assembly processes. The micro-castellated interposer is designed with standard component footprints that can be populated using automated pick-and-place machines and reflow soldering equipment. This substitution eliminates the need for highly skilled manual operators and magnification aids while maintaining part replacement capability for small geometry parts.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If scrapping existing product and re-layout of circuitry is performed, then circuit functionality is achieved, but productivity decreases and cost increases

Engineering Contradiction:

Improvecircuit functionalityVSAvoidbuild schedule

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs the circuit re-layout and wiring changes in advance by fabricating the micro-castellated interposer separately before assembly to the parent board. The interposer is designed and manufactured with the revised circuit functionality already incorporated, allowing it to be produced in volume using standard PCB manufacturing processes. This preliminary action enables the parent boards to be assembled without re-layout delays, maintaining productivity while achieving circuit functionality changes.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7507914B2Micro-castellated interposer

Publication Date: 2009.03.24 HONEYWELL INTERNATIONAL INC

AI summary

A miniature PWB with features that incorporate the required circuitry changes and component footprints, which has been enhanced with micro-castellations such as those found on ceramic surface mount packages. The miniature PWB is mounted on the circuit board using techniques well known in the art. This combination of technologies provides an adaptable, durable interconnect methodology, which allows for circuit and part changes without changing the layout of the base printed wiring board.