Our windows require optical coatings on both sides.....do they go on before or after your metals?

In almost all cases, the metal solderband coatings are applied after the optical coatings

Can you apply the metals directly over the optical coatings?

They can be, depending on the composition of the optical films, but a much more reliable hermetic seal will be made if the metals are deposited directly onto the substrate material.  The optical coating process normally requires a "tooling land area" around the perimeter of the window which will be free of the coatings, so this is rarely a problem.

We need the edges of our windows metalized, as well as the top surface perimeter......is this a problem?

Not at all, but you need to make us aware that this area is critical to your sealing process, as we need to take some special measures to make sure that you get good coating quality on the vertical edges of your windows.

Will the thickness of the metal on the edges be the same as the top surface metals?

No, they will be thinner by as much as 40%.....in fact it will be a tapered deposit, being thicker at the top and thinner towards the bottom of the edge.  This is the nature of sputter deposition. The top surface of the window is perpendicular to the incident "beam" coming off the target material, whereas the vertical edge is parallel to the flux, thereby resulting in more of a "glancing" angle of impact, with the top surface material arriving at the substrate pretty much "head on".  We apply enough metal thickness to ensure adequate solder wetting on the entire edge.

What if we don't want any metals on the vertical edge....topside only.....can you accommodate this?

Yes, but it will require special fixturing to protect the edge. For example, we can machine an aluminum  carrier plate(s) with a recess for each window, such that the windows are sunken into the carrier.

Why do you use Nickel-Vanadium rather than pure nickel?

We use magnetron type sputter guns.  Nickel is a magnetic material, which complicates the sputtering process as the nickel will shunt the magnetic field pattern at the target material surface, effectively canceling the magnetron's effectiveness, and resulting in very low sputtering yields. With the addition of a small amount (7% by wgt.) of Vanadium, the nickel is rendered non-magnetic, becoming fully compatible with magnetron sputtering.  For soldering purposes, NiV has become an accepted substitute for pure nickel and will integrate seamlessly into your soldering process.