| Specification field | Information to provide |
|---|---|
| Material | Family, manufacturer grade and permitted alternatives |
| Stack-up | Finished ceramic and conductor thickness on each level |
| Geometry | Outline, datums, holes, vias, tolerances and edge requirements |
| Finish | Pad metallurgy, layer thickness and selective areas |
| Assembly | Solder, wire bonding, die attach, mounting and temperature exposure |
| Verification | Electrical, dimensional and interface acceptance criteria |
Use a hierarchy of requirements
Separate mandatory performance and dimensions from preferred construction details. If a supplier is allowed to propose alternatives, state which requirements must remain unchanged. Identify critical-to-function dimensions and avoid unnecessary blanket tolerances.
Align all fabrication files
Conductor artwork, mechanical drawing, stack-up and notes should use one revision. Resolve conflicts between CAD dimensions and notes. State units, datum structure and the measurement convention for etched or plated conductor profiles.
Specify verification as well as design intent
Define how the delivered part will be accepted: dimensional checks, continuity, isolation, adhesion, finish or other agreed tests. Include relevant sample sizes and reporting requirements in the purchasing agreement. Do not assume a generic PCB standard covers every ceramic construction.
Engineering example
If copper width is critical to resistance, specify the finished dimension and where it is measured. A nominal artwork width may not represent the narrowest conducting section after etching.
Before you release the design
- Control one drawing revision across all files.
- Identify mandatory and negotiable requirements.
- Agree on measurement and acceptance methods.
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.