Measure the whole transition footprint
Compare all lands and connecting copper on every involved layer. The visible entry pad is not the complete footprint. A staggered structure may occupy a channel needed by another signal; a stacked structure may place demanding interfaces at a compact location.
Altium's via documentation describes both arrangements as ways to traverse multiple build-up layers. In a design review, turn that description into a layer-by-layer overlay so the impact on nearby routes is visible.
Avoid universal reliability rankings
Reliability evidence must correspond to the actual geometry, materials, process, and exposure. Do not infer that every staggered structure is acceptable because a different stacked structure experienced problems. Equally, do not treat a successful simple stack as proof for a deeper or differently supported arrangement.
Ask the fabricator which structures are established in its process and what evidence supports the proposed combination. Include whether a microvia sits over another microvia, a larger buried structure, or a separate target land.
Work through a routing example
Suppose a package pin needs access two build-up layers inward. A staggered path fits if the intermediate layer has space for the offset and connection. If that space removes an essential neighboring route, a stacked path or a different escape assignment may be worth evaluating. Compare both with the same reference-plane strategy.
- Check the intermediate land and neck geometry.
- Review the return-current transition alongside the signal.
- Identify which arrangements are allowed in the CAD rules.
- Use representative structures in any required qualification vehicle.
Keep mixed strategies intentional
A board can use different approved arrangements in different regions. Name each structure and scope its rules so an interactive routing shortcut does not introduce an unintended stack. Include a final check for coincident vias because a visually tidy layout can hide a prohibited combination beneath the surface.
Adjacent-layer access, one connection at a time
Dielectric · geometry + material
Core or build-up dielectric
Illustrative only. Copper thickness, dielectric construction and via spans require a reviewed stackup.
Common questions
Must all microvias on a board use one arrangement?
No. A mixed approach can be appropriate when every used structure is defined, manufacturable, and covered by the release requirements.
Is stagger distance just a drawing preference?
No. It affects land interaction, routing space, and the resulting structure. Obtain the permitted relationship for the proposed process.
References & further reading
Method & assumptions · General design guidance. Validate the proposed construction and acceptance criteria for your project.