RO4003C is an RF laminate in the RO4000 family. Electrical, processing and flammability requirements must be checked against the exact material rather than inferred from a related grade.
What to consider
A material substitution can change both circuit response and product requirements. Compare design Dk, loss, thickness and copper construction using the manufacturer’s data. In a hybrid HDI stack, confirm the bonding system and whether the selected microvia process is qualified for the RF dielectric.
A practical review example
A design originally using RO4350B should not be changed to RO4003C solely because a distributor lists a similar thickness. Check the electrical model and all relevant product requirements before approval.
Checks before release
- Check the complete material specification.
- Review bondply and thermal compatibility.
- Re-simulate sensitive RF structures after substitution.
Connect this decision to fabrication
Use the material selector to organize the initial discussion. Keep proposed values separate from the approved drawing and document the effect of any change on the rest of the construction.
- Identify the exact grade, glass style, resin content and copper foil.
- Compare Dk and Df only with their frequency and test method.
- Confirm the material system is qualified for the proposed via structure.
Technical references
RO4000 laminate data and processing resourcesReferences checked 2 October 2026. Manufacturer data describes its stated construction and is not an HDIPCB.org manufacturing commitment.