Solder Filled Vias for PCB

My project requires all vias to be solder filled. Anybody here knows a PCB fabricator who's capable of using solder of not less than 4% silver, with eutectic temperature greater than 215 degree C? I prefer Asian fabricators.

Why?
What size are the vias, finished hole size.
There are a variety of via filling techniques that PCB manufacturers employ, solder is not realy one of them.

The board will be use on high temperature environment. I don't really know what's the purpose of the solder filled vias but it is indicated as a requirement by the customer. The via size is 4020 (40mils outer diameter of the pad, 20 mils finished drill for the via). Solder needed is 96% tin 4 % silver.

ivan27807 said:

The board will be use on high temperature environment. I don't really know what's the purpose of the solder filled vias but it is indicated as a requirement by the customer. The via size is 4020 (40mils outer diameter of the pad, 20 mils finished drill for the via). Solder needed is 96% tin 4 % silver.

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filling the via is very good for conductivity. In impedance case it will reduce leakage.
which type of filling that depends upon your design & fabricator.

Filling vias is quite a complex and quite costly process. Filling with solder is not something I encounter these days, filling with epoxy and numerous other methods. Solder in a via can be very problematic, hence vias are plugged often to avoid solder going down the via during reflow. How does your customer imagine this will be processed by the manufacturer? And if 100% filling is not achived or there are voids you have more chance of thermal cracking of the via.
I should imagine with some sort of vacuum it could be done, but of all the via filling methods I have looked at, solder has never been one of them. In days of old when vias were larger and wave soldering was prevelant your vias would fill during wave soldering, but never uniformly, so it was prefferable to plug the vias to avoid the solder enetering the via. )n 0.5mm vias this is a big problem due to the small size.
I would talk to some manufacturers regarding the requirements (that you need to get from your customer, what do they want to achieve, better conduction either electrical or thermal, barrel cracking???) and the sit down before you get a price for the board.

http://www.electrochemicals.com/viafill07.pdf
R & D Circuits - Technology

Not sure if tin/silver solder can be eutectic, I know some tin/silver/sopper ones are.