Flexible Circuit Bonding methods

[loudig]

I have two flexible circuit materials - Polyimide (PI), and Polyethylene Terephalate (PET). I need to bond a thin metal tab to flexible circuit pads on each of these substrates. I have 4 different methods of bonding:

1. Solder
2. Ultrasonic welding
3. Laser welding
4. ICF/ACF (Isotropic conductive film/Anisotropic conductive film). This method is used for bonding LCD displays to rigid and flexible circuits.

Does anyone have experience with these bonding methods and what is preferential? The PET has a melt point around 200-255 deg C so I already know that this will not work with soldering. In contrast PI has a melt temperature around 352-388 deg C.

-loudig

 

[gerhardl]

You are not stating anything about size, ..and what about gluing?

 

[loudig]

I also neglected to mention that the bonds need to be electrically conductive. Glue is good if there's a good low profile conductive variety I suppose. It needs to have a very thin bond-line thickness. The tabs are terminals on a small battery. The tab sizes are roughly .12 wide x .15 and are about .015" thick.

 

[ScottyUK]

Check out the printable / dispensable conductive epoxies from AI Technology or Promatech. Long time since I worked in hybrids, maybe they have something to suit your application. Most of the other companies I still have cards for have either merged or vanished.

http://www.aitechnology.com/

http://www.promatech.co.uk/

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If we learn from our mistakes I'm getting a great education!

 

[tygerdawg]

loudig

I will soon have responsibility to do something very similar, improving existing methods. Current method is combination soldering and application of small amount of conductive epoxy to improve pull-strength and retention. I won't be able to get on this project until early next year, but I would very much like to monitor your investigation and results.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[loudig]

Thank you ScottyUK, I'll check these materials out.

tygerdawg - I'll be sure to keep you informed of what I decide to do with our bond method and material type!

-loudig