Arlon CuClad 6700 PTFE bondply: full guide to electrical properties (Dk 2.35, Df 0.0025), multilayer PCB lamination parameters, NASA/ESA space compliance, and how it compares to Rogers 2929 and CuClad 6250. Written for RF and microwave PCB engineers.
If you’ve spent any time designing high-frequency multilayer PCBs, you already know that the bonding material sitting between your substrate layers is just as critical as the laminate itself. Get it wrong, and you’ll spend weeks chasing impedance anomalies or delamination failures in the field. Get it right, and your stripline structure will hold its electrical properties through temperature swings, pressure cycles, and the general abuse of real-world deployment.
Arlon CuClad 6700 is one of those materials that, once you understand it properly, becomes a trusted tool in the RF engineer’s stack. This guide covers everything from the chemistry and electrical specs through to practical lamination parameters and multilayer stackup guidance โ written from the perspective of someone who actually has to build with this stuff.
What Is Arlon CuClad 6700?
Chemistry and Material Composition
CuClad 6700 is a chloro-trifluoroethylene (CTFE) thermoplastic co-polymer bonding film originally developed under Arlon’s microwave materials division, now marketed under Rogers Corporation following their acquisition of Arlon’s electronic materials business. It is specifically engineered for bonding PTFE-based substrates in microwave stripline packages and other multilayer PCB circuits.
The CTFE chemistry is an important distinction here. Unlike standard epoxy-based prepregs commonly found in FR-4 multilayer work, CuClad 6700 belongs to the fluoropolymer family โ giving it a dielectric profile that closely tracks the PTFE laminates it’s designed to bond. This means your electrical stack stays consistent, without the property mismatch you’d introduce by using a conventional prepreg between low-Dk PTFE substrate layers.
Where It Fits in the CuClad Family
The CuClad product line covers both laminates (CuClad 217, CuClad 233, CuClad 250) and bonding films (CuClad 6250 and CuClad 6700). The bonding films sit in the mid-range of the CuClad and DiClad laminate series’ dielectric constant spread, which makes them a natural electrical match for the most widely used substrates in the family.
CuClad 6700 is the higher-temperature variant of the two bonding films. Its sister product, CuClad 6250, uses an EAA thermoplastic co-polymer chemistry and processes at significantly lower temperatures. Choosing between them usually comes down to your lamination press capabilities and the thermal requirements of your specific multilayer build.
Arlon CuClad 6700 Key Electrical Properties
For RF and microwave engineers, electrical properties aren’t just numbers to put in a report โ they directly govern how your transmission lines behave at frequency. Here’s what matters:
Dielectric Constant (Dk)
| Property | Value | Test Condition |
| Dielectric Constant (Dk) | 2.35 | 10 GHz |
| Loss Tangent (Df) | 0.0025 | 10 GHz |
| Dielectric Constant (Dk) โ Alt. Source | 2.30 | 10 GHz |
The Dk of 2.35 falls comfortably in the mid-range of the CuClad laminate system. This is intentional. When you’re building a multilayer with CuClad 217 (Dk ~2.17) or CuClad 233 (Dk ~2.33) as your core laminate, the bonding film’s dielectric constant needs to be close enough that it doesn’t create localized impedance discontinuities at the bond interfaces.
The small variance you’ll see between datasheets (2.30 vs. 2.35) is a function of measurement methodology and material lot variation. For design work, using 2.35 as your design value and confirming with your fabricator’s measured data is the prudent approach.
Loss Tangent
A loss tangent of 0.0025 at 10 GHz is excellent for a bonding film. For comparison, standard FR-4 prepreg runs anywhere from 0.015 to 0.025 โ roughly an order of magnitude worse. If you’re designing above a few GHz, this difference is the reason why you’d specify CuClad 6700 rather than reaching for whatever bonding material is cheapest. The lower insertion loss translates directly to better system sensitivity and reduced thermal load on amplifier stages.
Physical and Thermal Properties
Thickness Options
CuClad 6700 is available in two standard thicknesses:
| Thickness (Imperial) | Thickness (Metric) |
| 0.0015 in | 0.038 mm |
| 0.003 in | 0.076 mm |
The choice between these two depends on how much copper trace height you need to encapsulate. A general rule of thumb: you need enough bondply thickness to fully encapsulate the etched copper traces plus provide the required additional dielectric between layers. For finer trace geometries, the 0.0015″ option works well. For heavier copper weights or designs with more substantial fill requirements, step up to 0.003″.
Thermal and Physical Properties Summary
| Property | Value |
| Thermoplastic Melt Temperature | 397ยฐF (203ยฐC) |
| Maximum Process Temperature | 475ยฐF (246ยฐC) |
| Water Absorption | Very low |
| Outgassing | Low |
| Form Factor | 24″ (610mm) roll and sheet |
| RoHS Compliant | Yes |
| NASA/ESA Space Compliant | Yes |
The melt temperature of 397ยฐF (203ยฐC) is high enough to provide stability in soldering operations yet still allows a workable press window. The low outgassing value is particularly relevant for satellite and space programs โ this is one of the reasons CuClad 6700 carries NASA/ESA compliance certification for space and satellite applications.
Arlon CuClad 6700 Key Benefits for PCB Engineers
Intrinsic Flame Resistance
The CTFE fluoropolymer chemistry provides inherent flame resistance without the need for halogen-based flame retardant additives. This is a meaningful advantage in applications where UL94 V-0 performance is required without compromising electrical properties โ which is exactly what happens when you load up a resin system with brominated flame retardants.
Excellent Match to Low-Dk PTFE Laminate Systems
This is the core value proposition of CuClad 6700 in a multilayer design context. When you’re building a stripline board using CuClad 217 or CuClad 233 as your signal layers, you need a bondply whose dielectric constant doesn’t create impedance bumps at each layer interface. The 2.35 Dk of CuClad 6700 sits close enough to the CuClad laminate range that your stack behaves as a near-homogeneous dielectric medium at microwave frequencies.
Shorter Press Cycle Than Thermoset Prepregs
Compared to high-frequency thermoset prepregs, CuClad 6700 offers a shorter overall lamination cycle. The thermoplastic resin’s hold time during pressing is shorter, which improves throughput on the press and reduces overall manufacturing cost. For high-volume production runs, this is a meaningful operational advantage.
Reworkability โ A Thermoplastic Advantage
One benefit that often gets overlooked in specification sheets is that CuClad 6700’s thermoplastic nature means it can be reheated to remelt and reflow the bonding film. This is a significant advantage over thermoset bondplies, which cure irreversibly. In a multilayer assembly that requires rework or correction before final cure, the ability to reverse the bond is extremely valuable โ particularly in prototype or low-volume defense and aerospace builds where the cost of scrapping a partially completed stack is substantial.
Space and Satellite Qualification
Compliance with NASA/ESA guidelines for satellite and space applications opens up CuClad 6700 for some of the most demanding programs in the industry. Low outgassing is an absolute requirement in space environments โ materials that offgas in a vacuum can deposit contamination on optical surfaces, solar cells, or sensitive sensors. CuClad 6700’s low outgassing profile satisfies these stringent requirements.
Multilayer PCB Lamination Process Guide
Getting CuClad 6700 lamination right is not complicated, but it is process-sensitive. Unlike FR-4 prepreg which tolerates a fairly wide process window, fluoropolymer bondplies reward careful attention to temperature uniformity and cool-down rate.
Surface Preparation
PTFE surfaces are notoriously difficult to bond. Before lamination, copper surfaces should be properly prepared โ options include:
- Chemical etchingย (preferred method for PTFE surfaces)
- Gas plasma treatmentย โ effective for both through-hole preparation and multilayer lamination adhesion promotion
- Sodium naphthalene etchingย (FluoroEtch or Tetra-Etch type treatments) to micro-roughen the PTFE surface
Avoid mechanical scrubbing of PTFE laminate surfaces after etching. The copper foil creates a dendrite pattern in the PTFE during lamination that is essential for subsequent bond quality โ mechanical abrasion can destroy this microstructure and compromise interlayer adhesion.
Handling should always be done wearing clean gloves to prevent transfer of skin oils to bonding surfaces. Once prepared, panels should be stored in a clean, dry environment and laminated within 24 hours of surface treatment.
CuClad 6700 Lamination Parameters
| Process Step | Parameter |
| Suggested Set Temperature | 450ยฐF (232ยฐC) |
| Minimum Bond Temperature | 400ยฐF (204ยฐC) |
| Maximum Process Temperature | 475ยฐF (246ยฐC) |
| Hold Time at Temperature | 15 minutes minimum |
| Lamination Pressure | ~100 psi (200 psi for complex fill) |
| Maximum Cool-down Rate | 10ยฐF/min |
| Removal Temperature | Below 200ยฐF (93ยฐC) |
A few process notes worth emphasizing from experience with PTFE multilayer lamination:
Use a thermocouple at the bond line. Don’t rely solely on press platen temperature. Place a thermocouple at the edge of the bond line (outside the working area) to confirm actual interface temperature. PTFE laminates are thermally insulating โ the temperature gradient between the press platen and the center of the stack can be significant, especially on thicker builds.
The 15-minute hold is non-negotiable. Insufficient time at temperature results in a failed or spotty bond. This is one of the most common causes of field delamination in PTFE multilayer boards โ the press cycle was slightly short, the bond looked fine visually, but adhesion was marginal.
Control your cool-down rate. Forced cooling faster than 10ยฐF/min without adequate pressure will cause warpage or partial debonding. If you’re transferring to a cooling press, make sure it’s still hot when you transfer โ never let the stack sit on a cold surface. Cool-down pressure should match the hot-press pressure.
Layup Procedure
- Lay the CuClad 6700 bonding film between the layers to be laminated, ensuring sufficient film area to encapsulate the full copper trace and pattern height
- Use adequate film thickness to provide the required dielectric spacing after flow
- Place thermocouple at bond line edge
- Preheat press to ~450ยฐF
- Apply ~100 psi pressure; increase to 200 psi for complex trace fills
- Hold at bond temperature for minimum 15 minutes
- Cool under pressure at โค10ยฐF/min to below 200ยฐF before panel removal
Availability and Format
CuClad 6700 is available in both roll form and sheet form at 24″ (610mm) width. There are no shelf-life limitations when stored in original sealed packaging at temperatures below 25ยฐC (77ยฐF) and relative humidity below 70%. Film rolls should be stored on edge (upright) or suspended by roll cores to prevent flat spots and creasing from the weight of the roll.
Typical Applications for CuClad 6700
Microwave Stripline Circuitry
Stripline is the primary application for CuClad 6700. A stripline structure buries the signal conductor between two ground planes โ which means you’re always dealing with a bonded multilayer structure. The dielectric properties of your bondply directly contribute to your controlled impedance. CuClad 6700’s Dk closely tracks the surrounding PTFE laminate, which simplifies impedance modeling and improves predictability of the finished product.
Hybrid Multilayer Constructions
In hybrid multilayer designs โ where PTFE-based RF layers are combined with other substrate types for digital or power supply layers โ CuClad 6700 facilitates the RF portion of the stack. Sequential lamination techniques using films with different melt temperatures allow complex hybrid constructions to be built reliably.
Heat Sink and Thermal Management Integration
CuClad 6700 can bond PCBs to heavy plate heat sinks, metal housings, and RF module enclosures. This is useful in power amplifier and high-power RF module applications where the circuit board needs to be thermally coupled to a chassis or heatsink structure.
Satellite and Space Electronics
NASA/ESA compliance makes CuClad 6700 suitable for space hardware. Applications include antenna feed networks, satellite transponder circuitry, phased array feed structures, and communications system boards where outgassing limits are strictly enforced.
Wireless Infrastructure
CuClad 6700 appears in Rogers’ own product selector guide as a recommended bonding material for wireless infrastructure applications โ including base station antennas, backhaul radios, and power amplifier boards. The combination of low loss, controlled Dk, and process reliability makes it well-suited to the high volumes and tightened electrical tolerances of telecom hardware.
CuClad 6700 vs. Other Rogers Bonding Films
When selecting a bondply for a high-frequency multilayer PCB, CuClad 6700 is one of several options in the Rogers portfolio. Understanding how it compares helps narrow down the right choice for your specific build.
| Bonding Material | Chemistry | Dk (10 GHz) | Df (10 GHz) | Melt Temp | Key Advantage |
| CuClad 6700 | CTFE Thermoplastic | 2.35 | 0.0025 | 397ยฐF (203ยฐC) | PTFE system match, space qualified |
| CuClad 6250 | EAA Thermoplastic | 2.32 | ~0.002 | 213ยฐF (101ยฐC) | Low temperature process, foam substrates |
| Rogers 2929 Bondply | Thermoset | 2.94 | 0.003 | Thermoset | Controlled flow, multiple lamination cycles |
| Rogers 3001 Bonding Film | Chlorofluoropolymer | ~2.3 | Low | ~265ยฐF | Very low Dk/Df, sequential lamination |
| CLTE-P | Thermoplastic | 2.98 | 0.0023 | 265ยฐC | Sequential lamination, low CTE |
Choose CuClad 6700 when your core laminates are PTFE-based (CuClad, DiClad, RT/duroid), you need space qualification, or your process requires the reworkability that thermoplastic chemistry enables.
Choose CuClad 6250 when your lamination press has lower temperature capability, or when bonding pressure-sensitive substrates like dielectric foam materials that can’t tolerate 450ยฐF processing.
Choose Rogers 2929 when you’re working in an environment that performs multiple lamination cycles (sequential lamination), need controlled resin flow for complex geometries, or your Dk requirements can tolerate the higher ~2.94 value.
Design Considerations for Engineers
Impedance Modeling With CuClad 6700
When building a controlled impedance stripline structure using CuClad laminate with CuClad 6700 bondply, treat the bond film as an additional dielectric layer in your stack calculation. The 2.35 Dk value should be used in your impedance solver โ most field solvers handle mixed dielectric stacks well, but verify that your solver handles thin bondply layers correctly. Some simplified calculators assume homogeneous dielectric, which can introduce errors when bonding film layers are comparable in thickness to trace height.
Copper Surface Finish Compatibility
CuClad 6700 bonds to the copper cladding on standard electro-deposited (ED) and rolled-annealed (RA) copper foils. For optimal adhesion to PTFE surfaces, chemical surface treatment (sodium-based etchants or plasma treatment) is required. If you’re designing a board that will use immersion gold or other surface finishes, confirm with your fab that the CuClad 6700 lamination is performed before any post-lamination plating operations that might affect adhesion chemistry.
Via and Through-Hole Considerations
Plasma treatment has been shown to promote adhesion in plated through-hole regions as well as at the lamination interface. For PTH reliability in a PTFE multilayer stack, confirm that your fabricator’s PTH preparation process is compatible with PTFE substrates โ standard desmear processes designed for FR-4 may not be appropriate.
For Arlon PCB fabrication, working with a fabricator experienced in fluoropolymer materials is strongly recommended. The process sensitivities of PTFE-based multilayers are meaningful, and fabricators without experience often underestimate the differences from standard FR-4 processing.
Useful Resources for Engineers
| Resource | Description | Link |
| Rogers Corporation โ CuClad 6700 Product Page | Official product page with downloads | rogerscorp.com |
| CuClad 6250 & 6700 Data Sheet (PDF) | Official Rogers datasheet with full lamination guide | Download PDF |
| Rogers Bonding Material Properties Tool | Interactive selector comparing all Rogers bondplies | tools.rogerscorp.com |
| Rogers High Frequency Product Selector Guide (PDF) | Full portfolio overview across all Rogers HF materials | Available on Rogers downloads page |
| Rogers Technology Support Hub | Technical papers, white papers, calculators for AES materials | rogerstechub.com |
| MatWeb โ CuClad 6700 Entry | Third-party material property database | matweb.com |
| IPC-TM-650 Test Methods | Standard test methods referenced in Rogers datasheets | ipc.org |
Frequently Asked Questions About Arlon CuClad 6700
1. Can CuClad 6700 be used with non-PTFE laminates?
Yes โ while CuClad 6700 is specifically optimized for bonding PTFE-based substrates, it can also be used to bond other structural and electrical components to the dielectric. That said, its primary value lies in its dielectric compatibility with the CuClad and DiClad laminate families. If you’re bonding to non-PTFE substrates, evaluate whether the 450ยฐF process temperature is compatible with those materials before committing to this bondply.
2. What happens if the lamination temperature is too low?
If the bond interface doesn’t reach the minimum 400ยฐF (204ยฐC) threshold, the thermoplastic film will not fully reflow and wet the mating surfaces. The result is a failed or spotty bond that may pass visual inspection but will fail under peel testing or thermal cycling. Always use a thermocouple at the bond line โ not just the press platen โ to confirm interface temperature.
3. Is CuClad 6700 compatible with lead-free soldering processes?
Yes. CuClad 6700 is RoHS compliant and its thermoplastic melt temperature of 397ยฐF (203ยฐC) provides adequate headroom above typical lead-free solder reflow profiles (typically 250โ260ยฐC peak). However, confirm the full thermal profile of your reflow process against the material’s service temperature limit. Repeated reflow cycles should be evaluated against potential bond fatigue.
4. What is the shelf life of CuClad 6700?
There are no shelf-life limitations when CuClad 6700 is stored in its original sealed packaging at temperatures not exceeding 25ยฐC (77ยฐF) and relative humidity below 70%. Proper storage orientation (rolls stored on edge or suspended from roll cores) prevents physical deformation of the film.
5. How does CuClad 6700 compare to Rogers 2929 Bondply for general multilayer RF applications?
The key differences are chemistry type and dielectric constant. CuClad 6700 is a thermoplastic with Dk of 2.35 โ ideally matched to PTFE laminate systems. Rogers 2929 is a thermoset bondply with Dk of ~2.94 โ better suited to hydrocarbon and ceramic-loaded systems like the RO4000 series. If your core laminates are CuClad or DiClad PTFE materials, CuClad 6700 will give you better dielectric continuity through the stack. If you’re in the RO4000 family, 2929 is the natural pairing. The other practical distinction is that CuClad 6700 can be reheated and rebonded (thermoplastic), while 2929 cures irreversibly (thermoset).
Summary
Arlon CuClad 6700 is a purpose-built PTFE bondply that belongs in any serious RF multilayer PCB design toolbox. Its CTFE thermoplastic chemistry delivers a dielectric constant of 2.35 and a loss tangent of 0.0025 at 10 GHz โ closely matched to the CuClad laminate family it’s designed to bond. The thermoplastic nature means shorter press cycles, reworkable bonds, and the low outgassing profile needed for space-qualified hardware.
For the fabricator, the 450ยฐF lamination window requires a capable press and careful thermocouple monitoring, but the process is well-documented and repeatable once characterized. For the designer, the dielectric match simplifies stackup modeling and gives confidence that the finished board will behave as simulated.
Whether you’re building a satellite transponder, a 5G base station power amplifier board, or a precision microwave filter, CuClad 6700 earns its place between the substrate layers of your high-frequency multilayer stack.
