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How do you handle, place, and align NanoFoil® for bonding?
NanoFoil® should be handled with tweezers, usually plastic or metal, but without a sharp tip. Place the NanoFoil between the two components that need to be bonded, along with two layers of solder. Align the solder, foil, and the components, leaving part of the NanoFoil visible so you have access for ignition.
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How many places do I need to activate the NanoFoil®?
For any bond less than 2 inches square, you will only need one ignition point. Large area bonds will need multiple ignition points so that the wave of energy intercepts in the middle of the bond.
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How do I prevent solder spray during bonding?
Solder spray is caused when the foil has too much energy that is not being absorbed by the solder, or because you need more ignition points so that the wave of energy meets in the center of the bond. If you are getting solder spray, try the following:
- Increase the ignition points
- Decrease the pressure
- Increase the solder layer
- Decrease the thickness of the NanoFoil®
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What is solder spray?
Solder spray is caused by excess solder that has been pushed out of the interface when the energy wave from the NanoFoil® passes through the interface.
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What materials can I bond with NanoFoil®?
NanoFoil® can bond any solder plated surfaces together. Tin-plated NanoFoil can be used to bond gold-plated surfaces together.
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Can I use solder paste with NanoFoil®?
No. Solder must be provided in the form of a preform, thermal spray, or by plating.
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Do I need to use a flux?
No flux is needed.
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What coatings do I need to apply to use NanoFoil®?
Approved surfaces for NanoFoil® include:
- Tin-plating
- Indium-plating
- Silver-plating
- ENIG coating
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What solders can be used with NanoFoil®?
Tin, indium, SAC alloys, or Pb-containing alloys
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Is pressure absolutely necessary?
Yes, some pressure is necessary to make sure that the NanoFoil® stays in place during activation and also ensures that the surfaces are as flat as possible.
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How much pressure is needed?
We recommend 20kg per square inch of force to bond 40um to 60um NanoFoil® to tin-plated surfaces.
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Is foam needed?
A foam platen is not always needed, but is helpful to evenly distribute the force across the entire interface when surfaces are not flat. Foam will also cushion the component from damage when applying the press.
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How large/small of a piece can you bond?
The smallest surface that has been successfully bonded using NanoFoil® is 4mm square, although we have heard that some customers have bonded surfaces as small as 1mm. The largest surface that we have bonded was 4 feet by 8 feet using multiple ignition points and daisy chained foil preforms.
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What if my parts are not flat?
If your parts are not flat (within 25um per inch), you may need to apply extra pressure to make sure the two interfaces touch during the NanoBonding process.
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Is process automation possible and/or available?
Automation is possible and we have three equipment vendors that have built automation equipment for NanoBonding. Please
contact us for more information.
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How can I eliminate voids when using NanoFoil®?
Voids are caused when the NanoFoil® is not in contact with the two interfaces that are being bonded during the reaction. To eliminate voids try the following:
- Increase pressure
- Increase or decrease the amount of solder
- Increase the thickness of the NanoFoil
- Clean the surfaces
- Bead blast the surfaces before solder plating
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Does NanoBonding provide a hermetic seal?
NanoBonding can provide a hermetic seal if the interface is wide enough to compensate for some of the cracks that will form when the NanoFoil® shrinks during activation. A NanoBonded solder joint that is 0.25 inch wide will most likely be hermetically sealed.
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Should I be worried about tin whiskers when using tin-plated NanoFoil® in electronic bonding applications?
Tin whiskers are a function of the time, temperature, and pressure to which the interface is exposed. Even pure tin solder joints do not always have tin whiskers.
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Is post cleaning necessary?
Post cleaning is rarely necessary when you have a proper NanoBond®. However, post cleaning may be necessary if you have some solder spray or when you have exposed NanoFoil® that flakes off after the reaction.
