CuClad 6700 is a thermoplastic bonding film for PTFE microwave constructions, with a higher bonding-temperature regime than CuClad 6250. The two films are not interchangeable adhesive plies: their electrical observations and thermal processing constraints differ. Selection begins with the entire manufacturing and service-temperature sequence.
Material system
Thermoplastic bonding film
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 2.35 | Typical; 10 GHz; datasheet lists IPC-TM-650 without a submethod or conditioning details. Not a separate Design Dk observation. Source |
| Dissipation factor | 0.0025 | Typical; 10 GHz; datasheet lists IPC-TM-650 without a submethod or conditioning details. Source |
Typical reported values are not a purchase specification. Process Dk, design Dk and values measured at different frequencies are not interchangeable.
Selection and design notes
- Consider it when a PTFE multilayer needs a film-bonding approach and the assembly can accommodate its processing window. Compare the thermal exposure of cores, copper treatment and any previously attached components before defining the lamination sequence.
- A change from 6250 to 6700 also changes the bondline dielectric and loss. Recheck impedance and coupling where fields occupy the adhesive rather than assuming the higher-temperature film is electrically neutral.
Thickness and copper options
Specify the supplied film gauge and verify final dielectric spacing after flow and compression around copper.
The film is unclad; adjoining foil treatment and PTFE surface preparation require documented compatibility.
Fabrication considerations
- Use interface thermocouples and the product's dwell, pressure and cooling instructions. Confirm complete fill around copper features and inspect bond quality on a representative stack; uneven pressure can make material-table comparisons irrelevant to the actual assembly.
Application fit
- PTFE multilayer bonding
- Microwave stripline structures
- Thermoplastic RF bondlines
Limits and substitution checks
- The selector does not label this film as lead-free-process compatible. A higher bonding temperature than 6250 is not permission to apply unrestricted reflow or repeated rework. No complete press recipe is inferred from the selector temperature alone, and long-term bond suitability needs the actual environment.