Different routes create different vias
A plated hole through a fired ceramic and a paste-filled via in a co-fired tape stack are not the same structure. Diameter, taper, aspect ratio, registration and conductor continuity depend on the route. Ask for rules for the actual material and thickness.
Specify the finished feature
Differentiate drilled or formed diameter from finished opening, plating thickness and fill condition. Define whether a hole is open, filled, capped or used for a pin. Where a via carries substantial current, check the actual conducting section and the interfaces to surface pads.
Inspect what can fail
Cracks, voids, incomplete metallization and poor registration may be invisible from a surface photograph. Select electrical continuity, sectioning or other appropriate inspection according to the feature’s function. Mechanical holes also need edge-distance and support review.
Engineering example
A via array used under a heat source may improve a multilayer package’s heat path, but filled-via conductivity, spacing and interfaces determine the result. Do not assume the array behaves like a solid copper block.
Before you release the design
- State electrical, thermal or mechanical function.
- Specify finished geometry and metallization.
- Agree on continuity and internal inspection criteria.
Sources and further technical reading
Manufacturer references support the material and process context. Worked examples and checklists are engineering guidance; they are not test results or supplier guarantees.