We are no longer guaranteeing quality of the electroplating results. The required maintenance for the number of monthly users no longer justifies continued operation, and we'll be phasing the plater out of operation entirely at some point in 2024 (theoretically). You can read below to understand more about the plater.
If you need vias: If you can get away with it, we recommend sizing your vias to be 1mm/40mil diameter holes (excluding the annular ring), and then soldering in a standard header pin. Otherwise, your best option is likely to get it fabricated professionally; see our PCB Design page for some fabrication house options.
The LPKF Contac S4 Electroplating System provides the ability to galvanically electroplate through-holes. Galvanic electroplating is a process by which your substrate sits in an acid bath (in this case, that’s sulfuric acid, H2SO4) along with a slice of the metal that you’re plating (in this case, copper). When a current is driven from the substrate, through the acid, and into the anode, a negative potential appears on the substrate, which draws copper ions from the copper sheets (called anodes) and distribute themselves onto any conductive surface on your substrate. In a gist. Google if you'd like more information on galvanic electroplating.
Critically, what this means is that the tool will plate copper everywhere that there is copper! This means any copper faces of your substrate will get additional copper on them. Astute readers will remember that the internal layer of your substrate (e.g. FR4) is not conductive, so an “Activator” (a conductive ink) is used to coat the inside of your holes with a conductive substance so that current can pass through the holes, and thereby plate your holes.
The LPKF Datasheet for the Contac S4: Contac S4-v1-0-en.pdf
The [Material] Safety Data Sheets (MSDS/SDS): LPKD_SDS.pdf
Our standard operating procedures: IN PROGRESS
Do I have to do this to get vias? This seems very time consuming. It is indeed time consuming, but plating is typically avoidable by making vias with a diameter of 40 mil (1 mm). A standard 0.1” header pin can then be pushed through and soldered on both the top and bottom. Boom.
What's the deal with training?
We used to lump the electroplater training into the plotter and laser trainings, but it was a long session with the plater normally tacked on at the end as an afterthought, and very few people actually used it. And then the plater was down for a prolonged period (in part due to the COVID pandemic). And then our professional-quality training videos were taking longer than expected. So we just decided to eliminate the plater from the standard training and spin it off as its own thing. This both reduced our standard training requirements and time, and provides a better training experience for those who are interested in actually using the plater.
So, here's the situation:
If you were trained on the plater in a previous life and would like access, great - shoot us an email. We'll see if we can work something out, though likely we'll just ask you to watch the video anyway, since it's only 30 minutes.
If you have never been trained on the plater but would like to be, also great - see our Training page for all the details. It's essentially the same process and the plotter/laser training, but for a different tool, and a bit shorter.
What are the different baths?
Baths 1 and 2 are different cleaners, called (appropriately) Cleaner 110 and Cleaner 210, respectively. Both are based on sodium metaborate. Bath 3 is Activator 310, a carbon-laced liquid that provides a conductive pathway for the copper plating onto non-conductive surfaces, such as FR4. Bath 4 is a ViaCleaner that isn't used at the Hive (as of Spring 2021). Bath 5 is called Copper Plater 400; it's sulfuric acid (97% strength) and copper sulfate. Don't stick your hand in it. Please. See the MSDS for details on these.
Why don't we use bath 4?
Bath 4 is called “ViaCleaner”. In essence, LPKF realizes that the Activator will adhere somewhat to the copper layers, even after a thorough rinse. ViaCleaner is more effective at removing stuck-on activator. This isn't a huge issue - the plating still works perfectly fine without it - but it makes the finished product cleaner, a bit more even, and it's very useful for blind vias. However, The Hive can't do more than two layer boards, so blind visas aren't an issue. Therefore, we feel the amount of error inherent in the electroplating process in the Semi-Clean room is large enough that the benefits of adding an additional step would be minimal. See LPKF's slide deck on this: LPKF ViaCleaner_Process Steps and Benefits.pdf
If you'd like cleaner finish, you can try scrubbing the board thoroughly after the curing process before what would be Bath 4.
Is tin plating available?
Theoretically, but we don't carry the necessary chemical for Bath 6 to actually do it. However, if you're interested, it takes between 4-8 weeks for us to get a chemical order from them, so you can let us know you're interested, and we'll look into picking some up. Won't be fast though. Sorry - the issue lies with LPKF's chemical procurement process, unfortunately.
How much copper is plated? Can I specify this?
The tool estimates a plating rate of approximately 0.14 um/min, which means that their standard 2 hour plating adds an additional 16.8 um of copper. This is highly speculative! We have done no work to confirm this numbers (because the equipment to do so is expensive). Therefore, we strongly advise you to use our standard processing profile; this is improve your plating outcomes. If you reduce the time, you may get less copper, but you may also get a less consistent plating job across the substrate, or incompletely plated vias, or other misfortunes.
If you have specific requirements for plating thickness, please email us (hive-pcb@ece.gatech.edu) so that we can discuss your options further.
What about RF application? Is there any way to mask certain regions?
For those unaware, RF application has specific trace thickness requirements, in addition to everything else. This makes plating in our standard process very challenging because it adds copper onto the sheet everywhere, increasing the eventual trace thickness, which is difficult to account for.
To try and mitigate this issue, we provide a chemically-resistant tape that has been shown to provide some masking capabilities. The tape is a beige color, and should sit underneath the plater. The trick is to apply the tape before drilling but after the “Placement” step; make sure to put tape down around the edges of the board so that, when you remove it to add the tape, you can place it back in the same spot before starting the drilling. We recommend using a roller to make sure the tape is fully contacted with the substrate; any leaks may ruin the design.
Can I electroplate other materials?
If you're asking about other substrates to plate copper onto, then yes, this should be possible. There are a few tricks here: the material you're trying to plate must not react negatively with sulfuric acid, and it must be conductive. The first constraint is primarily a safety thing; we don't want to generate any dangerous fumes accidentally. For the second, if the material is already conductive, then great! If not, you can use the activator (assume constraint #1 still holds) or you can find some other way to conducti-fy it.
If you're interested in plating a different metal, such as silver or tin, it may be possible.
Either way, please contact us first! DO NOT ATTEMPT THIS WITHOUT PRIOR APPROVAL!! Doing so could have serious repercussions for you, both from a health perspective and an academic one.