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Home > Guidelines & Resources > Via Hole Design Guidelines

Via Hole Design Guidelines

Ion Beam Milling offers customers a choice of either plated through holes (VIAs) or solid filled VIAs.  Our plated holes are laser drilled de-slagged and go through multiple cleaning steps to ensure that metallization will properly adhere without flaking, peeling, or blistering.

The holes are then sputtered and plated from both sides to ensure complete coverage of the Via hole sidewalls.

Recommended Minimum Annular Borders around Through Holes

Recommended Minimum Distance Between Via Holes

While the above specifications are recommendations based upon our experience, Ion Beam Milling can accommodate different sizes and configurations.  Please contact us for more details.

For plated Via Holes, a general rule of thumb is to maintain a 1:1 aspect ratio between the thickness of the substrate and the diameter of the hole due to the challenge of ensuring sufficient metalization throughout the entire hole during the sputtering process.  This means, for example that a substrate 0.25 thick should have holes no smaller than 0.25 in diameter.  That said, other diameters are possible as noted in the chart below:


Substrate Thickness Preferred Min. Hole Diameter Allowable Min. Hole Diameter
.005 .005   .003 - .005
.010  .010
.020  .020  .010".020
.025  .025  .012".025

As an alternative to plated Vias, Ion Beam Milling offers solid filled Vias upon request.  These have the advantage of providing superior top to bottom conductivity between the top and bottom surfaces of the substrate.
We offer three alternative metallization schemes:

  • Solid gold (Au) filled vias
  • Solid silver (Ag) filled vias
  • Solid copper-tungsten (CuW) filled vias

Filled Via Holes generally fall between .004-.007 in diameter, however other sizes available upon request

Ion Beam Millings engineering department is happy to discuss your needs with you and to recommend solutions to your particular design challenges.  Please contact us with any questions you may have.