Identify the supplied construction
Determine whether the proposed bonding material includes a dielectric carrier or is an adhesive film, and identify its grade. Supplier naming varies by product family; use the actual sheet and ordering code. Draw its place between conductor and dielectric layers. The four-layer stackup guide shows why bonding layers must be visible in a multilayer discussion.
Bonding layer definition
| Decision | Define | Review |
|---|---|---|
| Material form | Carrier-based or adhesive-only product | Exact grade and supplier sheet |
| Location | Layer interfaces and regional extent | Complete section drawing |
| Finished section | Bondline and conductor pattern assumptions | Thickness and electrical model |
| Open regions | Intentional nonbonded areas | Boundary construction and inspection |
Map where bonding is required
Distinguish fully bonded areas from intentional nonbonded regions. Show boundaries, termination details, and any nearby holes or exposed conductors. A single global stack does not describe a selectively bonded design. Review the selective-bonding guide before using free spans as a mechanical feature; this adds construction and inspection decisions rather than simply deleting adhesive from a drawing.
Agree finished geometry with the process
Record incoming material thickness and the assumptions for the laminated section separately. Copper pattern, fill needs, and processing can make an unreviewed arithmetic total misleading. Ask the fabricator to return the proposed material sequence and finished-thickness approach. Where electrical spacing is critical, reconcile the reviewed bonding construction with the impedance model before releasing conductor geometry.
Before you release the design
- Number every bonding layer.
- Show material extents by region.
- Mark nominal versus finished dimensions.
- Review bondline changes with electrical design.
Watch points
- Deleting a bonding layer can create an unsupported construction whose transitions are not defined.
Practical questions
Is bondply the same as coverlay?
Their intended functions differ. Identify the supplier product and its place in the stack rather than assuming the names are interchangeable.
Can bondply thickness be added directly to a total?
It can be an explicit planning assumption. Finished thickness and tolerance still need agreement for the proposed process and conductor pattern.
Technical references
References support the material or design context. Check the exact grade, part number, document revision and project conditions before release.Updated 27 September 2026 · Technical content policy · Engineering guidance supports project review; the agreed drawing defines the build.