Advantages of Pads Only & Panel Plating Techniques

By Katya Kaslow

One of the primary decisions faced by our customers is whether to employ pads-only or panel plating when designing a flex circuit. You can see the two techniques in the image to theright: Figure A shows a 2-layer flex circuit with pads-only plating, whereas Figure B shows another circuit with panel plating.

Customers often ask what the advantages and disadvantages are of both techniques, in hopes of determining the best fit for their needs. The first option is the panel plating technique which features additional plated copper thickness throughout the whole panel. The big advantage of the panel plating option is the lower cost of the technique; production costs are reduced due to having a shorter process. In addition to its affordability, panel plating is the preferred technique for applications that require greater current carrying capabilities as it allows Minco to add copper without increasing the thickness of the base copper beyond what is standard.

Some disadvantages of panel plating include a decrease in flexibility due to the copper thickness being increased throughout the entire panel. Another disadvantage of this technique is found in the etch stage of the production process, where precise features can be more difficult to etch.

Differing from the panel-plating technique is pads-only plating, also known as button plating. Pads-only builds up the copper thickness of the pad and barrel while adding only a very thin layer of copper to the remainder of the panel.

There are many more advantages of the pads-only technique. By only adding the thicker electro-deposited copper to the pads, it makes for a much easier etch process. Another advantage includes a greater amount of flexibility since the copper doesn’t cover the bend areas. Base foils, which are typically rolled annealed copper, are more flexible than electro-deposited copper. In certain cases, the pads-only technique allows for less adhesive to be used when filling between the conductors. This also aids in increased flexibility.

The pads-only technique is the more expensive of the two options, thanks to the extra steps brought on during the production process—there are three more processes than panel plating, contributing to the increased pricing.

Both techniques offer advantages and disadvantages that can impact a project. If uncertain on which technique is best for your needs, contact Minco today or download our Flex Circuits Design Guide to learn more about our capabilities.

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