PCB Registration Coupon Misregistration Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ensuring proper alignment between layers of printed circuit boards (PCBs) during manufacturing is challenging due to factors like thermal expansion, and existing methods may not accurately detect misregistration, which can lead to PCB quality issues.
Innovation Solution
A method and apparatus using resistance measurements on registration coupons to determine misregistration between internal layers of PCBs by measuring resistances between center and peripheral terminals, calculating conversion factors, and determining distance and direction of misregistration along axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance measurements are performed between center terminal and peripheral terminals on registration coupons, then misregistration distance and direction can be accurately determined, but the PCB structure becomes more complex with additional terminals and coupons
Solution Approach 1:
The PCB is segmented into functional areas by dividing it into multiple panels, each containing registration coupons with specific terminal configurations. This allows misregistration measurement to be performed on individual panels rather than requiring a complex overall structure, reducing the device complexity while maintaining measurement precision through localized measurement points
Solution Approach 2:
Registration coupons serve as intermediary structures that facilitate misregistration measurement without requiring direct measurement between all layers. The coupons include center terminals and peripheral terminals that act as mediators, enabling indirect but accurate measurement of misregistration between internal layers through resistance measurements, thus avoiding the need for a more complex direct measurement system
2Adaptability or versatility
If multiple registration coupons with multiple terminals are added to measure misregistration on multiple layers, then measurement capability is improved, but manufacturing cost and time increase
Solution Approach 1:
The registration coupon design provides multi-functionality by enabling misregistration measurement for multiple internal layers simultaneously through a single coupon structure with multiple peripheral terminals. Each peripheral terminal is electrically coupled to the center terminal on different internal layers, allowing one coupon to serve multiple measurement purposes across different layers, thus improving adaptability without proportionally increasing manufacturing complexity
Solution Approach 2:
The registration coupons are incorporated into the PCB panel during the manufacturing process itself, rather than being added as a separate post-manufacturing step. The center terminals and peripheral terminals are pre-configured with appropriate electrical couplings to internal layers during PCB fabrication, enabling misregistration measurement capability to be built into the base structure before final assembly, thereby reducing additional manufacturing time and cost
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
Accurately detects misregistration along both x and y axes, improving PCB manufacturing processes and enabling the production of more complex PCBs by identifying and correcting alignment issues.
Implementation Method 1
measuring a first resistance between a first center terminal and a first peripheral terminal of a first registration coupon
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and apparatus for determining misregistration of internal layers of a PCB using resistance measurements is disclosed. In one embodiment, a method includes measuring a first resistance between a first center terminal and a first peripheral terminal of a first registration coupon on a printed circuit board (PCB) panel (10) including at least one PCB (15). The method further includes measuring a second resistance between the first center terminal and a second peripheral terminal of the first registration coupon, wherein the first and second peripheral terminals are associated with a first internal layer of the PCB. A difference between the first and second resistances is then calculated. Then, based on this difference, a determination is made of a distance of misregistration of the first internal layer, if any, along a first axis.