• Skip to primary navigation
  • Skip to main content
  • Skip to footer

support@expresspcb.com

Support Hours: Monday - Friday 7:30 AM to 5:00 PM Pacific.


ExpressPCB

ExpressPCB

ExpressPCB

  • PCB CAD Software
  • ExpressPCB Manufacturing Service
    • Manufacturing Capabilities
    • MLB Construction
  • ExpressPCB Support
    • FAQs
    • ExpressPCB Plus Release Notes
    • ExpressPCB Classic Release Notes
  • My Account
Download Plus Download Classic

Slivers, Random Shorts And How to Prevent Them

You are here: Home / Blog / Slivers, Random Shorts And How to Prevent Them

March 25, 2016 by expresspcbadmin Leave a Comment

No, I’m not talking about bad memories of a camping trip when I was 10 years old. Wearing 80s short shorts and running through the woods isn’t a great idea, neither is designing a PCB that increases the chance of a different kinds of slivers. Copper Slivers. These sneaky little devils seemingly pop up randomly creating all kinds of havoc.

Copper Slivers are an issue for all PCB Manufacturers. They are just a side effect of the PCB Manufacturing process in which chemical etching removes copper from the FR4 laminate. Contrary to most other manufacturing processes where you build your product by adding material, Printed Circuit Boards are partially created by removing material. In this case traces, pads and planes are created by printing a resist over the areas where copper is supposed to stay and chemically etching the remaining copper away leaving the traces, pads and planes.

The intent of the chemical etch process is to dissolve away the unwanted copper. But if there are extremely long, thin sliver-like features to be etched away, these features can sometimes detach as chunks before they fully dissolve. The sliver chunks are then floating in the chemical bath where they might potentially land on another board before they fully dissolve.

Equally risky is when the sliver is intended to stay on the board, and is protected by resist. If the sliver is narrow enough, the copper baths may etch away just enough copper underneath to partially detach the sliver. Now the sliver is flopping around in the bath, invariably it flips over onto your own board, and shorts out other traces.

This is where PCB Layout Design comes into play. When laying out your PCB it is best to avoid leaving very narrow areas of copper. This is usually caused on filled planes where trace and pad clearance intersect. Below are some examples. ExpressPCB Manufacturing has a minimum etching resolution of 0.006”. Anything at or above this will be fine.

This first example shows two locations where there is a risk of a copper sliver breaking off during chemical etching. Since the trace clearances converge, at a certain point the copper goes below 0.006”. The small piece of copper left between the two pad clearances is below 0.006” as well.Copper-Slivers

This second image shows what happens when the sliver breaks during chemical etching causing a short.

This sliver can end up anywhere on the PCB. Some PCBs may not be affected and some may have a sliver or multiple. Due to the random nature, each pcb may have slivers in different areas depending on where the sliver settles. As you can imaging this can be a nightmare to troubleshoot because no two boards would have the same short in the same location.Copper-Sliver-Post-Manufacture

The best way to prevent this is to simply move your traces and pads to create the appropriate space or reduce the clearance around the traces and pads. Example below.

In this image both risk areas at the trace and pads are adjusted to at least 0.006” apart. Spending a little extra time on this simple design detail can save you a lot of time and money!no-slivers

Blog

Subscribe to our newsletter

Get the latest posts delivered right to your inbox

Reader Interactions

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Footer

Support Hours

Support Hours: Monday - Friday 7:30 AM to 5:00 PM Pacific Time

We provide support to our customers by email. Our support staff responds to questions the same day and often within just an hour or two.

You can contact ExpressPCB about our CAD software, our circuit board manufacturing service, placing orders, payment of orders, or orders previously submitted by sending email to:
support@expresspcb.com

Sitemap

  • Home
  • PCB CAD Software
  • Express PCB Manufacturing Service
  • News
  • FAQs
  • Support
  • My Account

Newsletter

Get the latest news, events and announcements straight to your inbox.

By providing your email address you are agreeing to receive software and service updates, latest news and information from ExpressPCB. Privacy Policy

Copyright © 2022 ExpressPCB. All rights reserved.

Request Download


Download

By requesting ExpressPCB Classic you are agreeing to receive email regarding software and product updates, industry news and discount codes from ExpressPCB. Privacy Policy

Request Download


download

By requesting ExpressPCB Plus you are agreeing to receive email regarding software and product updates, industry news and discount codes from ExpressPCB. Privacy Policy