DuPont Pyralux LF7002R pairs 1 oz rolled-annealed copper with an ultra-thin 0.5 mil polyimide substrate for compact single-sided flex circuits. Full specs, design rules, current capacity tables, and fabrication tips for PCB engineers.
There’s a specific kind of design problem that DuPont Pyralux LF7002R solves cleanly. You need the current-carrying capacity of standard 1 oz copper, but the total circuit stackup has to be as thin as possible — thin enough to hit a tight bend radius, thin enough to fit inside a compact enclosure, or thin enough to keep weight down without dropping to half-ounce copper and accepting the current limitations that come with it. LF7002R is the answer to that problem. It pairs full 1 oz rolled-annealed copper with one of the thinnest polyimide cores available in the Pyralux LF single-sided lineup: just 0.5 mil (12.5 µm) of Kapton® film bonded through a 0.5 mil acrylic adhesive. The result is a thin substrate flex material that gives you more conductor than LF7012R without the thicker dielectric of standard 1 oz grades. This guide covers everything a flex circuit engineer needs to know before specifying it.
What Is DuPont Pyralux LF7002R?
DuPont Pyralux LF7002R is a single-sided, acrylic-bonded copper-clad flexible laminate from DuPont’s Pyralux LF product family. The construction places 1 oz/ft² rolled-annealed copper foil on a 0.5 mil (12.5 µm) Kapton® polyimide core, bonded with a 0.5 mil (12.5 µm) C-staged proprietary acrylic adhesive. It is a single-sided grade — one copper layer, one PI core, one adhesive layer — supplied in 24 × 36 inch sheet form.
One important note for procurement and engineering specs: LF7002R is not IPC-4204/1 certified in the standard published DuPont product table. Engineers specifying this grade for applications that mandate IPC-4204/1 compliance should verify certification status directly with DuPont or their authorized distributor, and consider IPC-certified LF grades like LF7011R if that standard is a hard requirement.
Decoding the LF7002R Part Number
Every character in a DuPont Pyralux LF product code carries construction information. Understanding the naming logic helps when comparing grades, reviewing BOM substitutions, or evaluating supplier quotes:
| Code Segment | Meaning |
| LF | Acrylic-based flexible laminate family (Kapton® PI + modified acrylic adhesive) |
| 7 | Single-sided copper-clad construction |
| 0 | Denotes this construction group in the single-sided matrix |
| 0 | 0.5 mil (12.5 µm) adhesive layer |
| 2 | 0.5 mil (12.5 µm) Kapton® polyimide core |
| R | Rolled-Annealed (RA) copper foil |
The copper weight of 1 oz (305 g/m²) is defined by the product group designation in the single-sided matrix rather than by a single digit in isolation — which is why reviewing the full DuPont LF construction table alongside the part number is always the right approach rather than digit-parsing alone.
Full Material Specifications for LF7002R
DuPont Pyralux LF7002R uses the same Kapton polyimide film and proprietary acrylic adhesive chemistry as the rest of the LF family. The construction is fully cured at delivery — no additional cure step is needed during fabrication.
Physical Construction
| Parameter | Specification |
| Copper Type | Rolled-Annealed (RA) |
| Copper Weight | 1 oz/ft² (approx. 35 µm / 305 g/m²) |
| Adhesive Thickness | 0.5 mil (12.5 µm) |
| Polyimide Core Thickness | 0.5 mil (12.5 µm) |
| Construction | Single-sided |
| IPC-4204/1 Certified | No (verify current status with distributor) |
| Sheet Size | 24 in × 36 in (610 mm × 914 mm) |
| Pack Range | 4 to 25 sheets per pack |
Typical Electrical Properties
| Property | Value | Test Reference |
| Dielectric Constant (1 MHz) | ≤ 3.5 | IPC-TM-650 2.5.5.3 |
| Dissipation Factor (1 MHz) | ≤ 0.04 | IPC-TM-650 2.5.5.3 |
| Surface Resistance | ≥ 10⁶ MΩ | IPC-TM-650 2.5.17 |
| Volume Resistance | ≥ 10⁶ MΩ·cm | IPC-TM-650 2.5.17 |
| Dielectric Strength | ≥ 1000 V/mil | IPC-TM-650 2.5.6 |
These values are consistent with Pyralux LF family behavior. At 0.5 mil total dielectric thickness (PI + 0.5 mil adhesive = 1 mil composite), the physical insulation layer is very thin. Voltage isolation and dielectric standoff are not LF7002R’s primary value proposition — this is a signal and low-to-moderate current routing material, not a high-voltage isolation laminate.
The Design Logic Behind 1 oz Copper on a 0.5 mil PI Core
To understand why DuPont Pyralux LF7002R exists as a distinct grade, it helps to trace the engineering trade-off it’s designed to manage. The tension is between two competing demands: enough copper to carry meaningful current, and a dielectric thin enough to minimize total stackup thickness and enable tighter bend radii.
Why Not Use Standard 1 oz / 1 mil PI?
The workhorse single-sided grade in the LF family at 1 oz copper is LF8022R — 1 oz RA copper on a 1 mil PI core with 1 mil adhesive. That grade is IPC-4204/1 certified and widely fabricated. But its total dielectric package (1 mil adhesive + 1 mil PI = 2 mil) adds meaningful thickness to the stackup that flows directly into the minimum bend radius calculation. Per IPC-2223 guidance, static flex minimum bend radius runs approximately 6 × total stackup thickness; dynamic flex runs 100 ×. Every mil of dielectric thickness you can eliminate translates to a measurably tighter achievable bend radius.
LF7002R swaps the 1 mil PI and 1 mil adhesive of a standard 1 oz grade for 0.5 mil PI and 0.5 mil adhesive. That drops the total dielectric contribution from 2 mil to 1 mil — a 50% reduction in the non-copper component of the stack. If your mechanical constraints are tight and you can’t drop to 0.5 oz copper without losing current capacity, this is precisely the construction that resolves the conflict.
Why Not Use 0.5 oz Copper Instead?
LF7012R (0.5 oz / 0.5 mil PI) is thinner overall and achieves the minimum possible stackup for a single-sided LF grade. But 0.5 oz copper (approximately 17.5 µm / 153 g/m²) carries roughly half the current of 1 oz copper at the same trace width and temperature rise. For designs where signal traces dominate and current capacity is not the concern, 0.5 oz is sufficient. For designs where power rails, motor drivers, LED arrays, or sensor excitation circuits share the same layer with signal routing, the jump from 0.5 oz to 1 oz copper is a practical necessity — not a luxury. LF7002R fills that need with the thinnest available PI core at that copper weight.
LF7002R in Context: Comparison With Key LF Single-Sided Grades
Understanding where LF7002R sits in the single-sided LF matrix helps clarify when it’s the right specification decision and when a neighboring grade is the better fit:
Pyralux LF Single-Sided Family — Key Grade Comparison
| Product Code | Cu Weight (oz) | Cu Type | PI (mil) | Adhesive (mil) | IPC-4204/1 |
| LF7012R | 0.5 | RA | 0.5 | 0.5 | No |
| LF7002R | 1 | RA | 0.5 | 0.5 | No |
| LF7062R | 0.5 | RA | 0.5 | 1 | No |
| LF7011R | 1 | RA | 0.5 | 1 | Yes |
| LF8012R | 1 | RA | 0.5 | 1 | Yes |
| LF8022R | 1 | RA | 1 | 1 | Yes |
| LF7008R | 2 | RA | 0.5 | 1 | Yes |
LF7002R occupies the slot of thinnest-adhesive, thinnest-PI construction at 1 oz copper. Its direct neighbor LF7011R adds a thicker 1 mil adhesive layer and gains IPC-4204/1 certification, making it the better choice where that standard is required. LF7002R is the option when minimizing adhesive thickness is itself a design objective — for example, when total stackup height is the binding constraint and certification requirements allow it.
Rolled-Annealed Copper at 1 oz: Why RA Matters at This Weight
The “R” suffix on LF7002R confirms rolled-annealed copper foil — a designation that matters beyond marketing language at 1 oz weight.
RA copper foil is produced by mechanically working and annealing copper strip, aligning the grain structure horizontally parallel to the foil plane. This lamellar grain structure distributes bending stress across many crystal planes and gives RA copper its characteristic ductility — elongation values typically in the 20–45% range. Electro-deposited copper has a vertical columnar grain structure with elongation in the 4–11% range.
At 1 oz copper weight, the foil thickness is approximately 35 µm. That’s thick enough that grain structure behavior under bending stress is consequential. For dynamic flex applications, the RA designation is not optional — 1 oz ED copper in a repeated-cycle flex application will develop fatigue cracks faster than RA foil at the same geometry. For static applications where bend cycles are minimal, ED would be technically acceptable, but LF7002R standardizes on RA for the full flexibility of application choice.
One note worth knowing from fabrication experience: for extremely fine-pitch traces below 3 mil (75 µm), ED copper can offer marginal advantages in etch uniformity. But for most design pitches on a 1 oz layer — where trace widths above 3–4 mil are the working territory — RA copper etches well with standard wet chemistry processes.
Fabrication and Processing Parameters
DuPont Pyralux LF7002R processes under the same standard Pyralux LF laminating conditions:
| Parameter | Range |
| Part Temperature | 182 – 199 °C (360 – 390 °F) |
| Pressure | 14 – 28 kg/cm² (200 – 400 psi) |
| Time at Temperature | 1 – 2 hours |
The acrylic adhesive is fully C-staged at delivery. No additional cure cycle is needed during standard fabrication steps.
Handling and Processing Notes Specific to LF7002R
Panel rigidity: With only 0.5 mil PI and 0.5 mil adhesive, the dielectric component of LF7002R offers very little stiffness on its own. Handling unsupported panels during imaging, etching, and coverlay lamination requires appropriate backing fixtures and minimized unsupported span lengths. Panels can distort under their own weight if handled carelessly.
Registration tolerance: Thin PI film has less inherent dimensional stability than 1 mil or 2 mil PI under thermal processing. Monitor registration across the panel carefully during photolithography and confirm that thermal cycling during etching doesn’t introduce unacceptable shift. Panels that run through multiple wet-chemistry steps on thin PI require more process discipline than standard-thickness grades.
Coverlay selection and bonding: DuPont Pyralux LF coverlay is the compatible companion material. For LF7002R’s thin adhesive construction, confirm that coverlay bonding dwell time and pressure are adequate to develop full peel strength. On thin constructions, the bonding interface is more sensitive to temperature and pressure uniformity across the press platen. Validate adhesion strength during process qualification.
Sharp edges: Like all copper-clad laminates, LF7002R sheets have sharp metal edges. Handle with appropriate gloves and follow DuPont’s published safe handling guidance for Pyralux materials.
Storage: Maintain in original sealed packaging at 40–85°F (4–29°C), below 70% relative humidity. Polyimide film is hygroscopic — moisture absorption prior to processing degrades adhesion quality at the coverlay and adhesive bonding steps.
Current Carrying Capacity and Trace Design at 1 oz
At 1 oz copper, LF7002R supports meaningfully more current per trace than 0.5 oz grades. Using IPC-2152 as the calculation baseline for external conductors in free air at a 10°C temperature rise:
| Trace Width | 1 oz Cu Approx. Current |
| 25 mil (0.635 mm) | ~0.9 A |
| 50 mil (1.27 mm) | ~1.4 A |
| 100 mil (2.54 mm) | ~2.1 A |
| 200 mil (5.08 mm) | ~3.3 A |
| 500 mil (12.7 mm) | ~5.8 A |
These are reference values; run IPC-2152 calculations for your specific geometry, ambient conditions, and acceptable temperature rise. For designs mixing power delivery traces and signal routing on the same LF7002R layer, the current tables confirm that 1 oz copper gives significantly more headroom than 0.5 oz at practical trace widths.
Design Rules for Flex Circuits on LF7002R
These guidelines apply to circuits built on DuPont Pyralux LF7002R as the base laminate:
Bend Zone Trace Layout
Route traces perpendicular to the bend axis in the flex region. This orientation subjects the copper to pure bending stress — the most favorable loading for RA copper — rather than the combined bending and torsional stress that angled traces experience. Avoid placing vias or plated through-holes in or near the bend zone; copper-plated barrel walls crack under repeated bending stress, and the standard guidance is to keep vias at least 100 mil (2.54 mm) from the bend tangent line.
For dynamic flex with 1 oz copper, the minimum bend radius must be calculated conservatively. At this copper weight, 1 oz is at the upper end of what IPC-2223 treats as flex-appropriate — thinner 0.5 oz copper is preferred for high-cycle dynamic applications. If the design requires both 1 oz current capacity and aggressive bend cycles, verify with flexure testing during design validation.
Stiffener Integration
LF7002R’s thin PI core means the bare laminate has minimal mechanical rigidity. Any component mounting area, connector landing, or test point zone should include a stiffener — FR4, polyimide sheet, or stainless steel — adhesively bonded to the back side. The stiffener edge should stop at least 1.0 mm from the bend tangent to avoid creating a hard-soft transition point at the bend radius. Apply strain relief epoxy at the stiffener edge in vibration-prone environments.
Pad Anchoring
Thin PI substrates are more susceptible to pad lifting than thicker constructions. All exposed copper pads should be anchored with coverlay overlap, teardrops at trace-to-pad transitions, and if necessary, spur extensions into the coverlay to add mechanical bond surface area. For through-hole pads on a single-sided flex, the annular ring geometry and teardrop reinforcement are the primary protection against peel-off under connector insertion or cable termination loads.
Real-World Applications for DuPont Pyralux LF7002R
Compact wearable and IoT devices with power distribution requirements — Wearable health monitors, GPS trackers, and IoT sensor nodes often combine a tight form factor with real current distribution needs — battery charging circuits, motor drivers for haptic actuators, or LED driver traces. LF7002R bridges the gap between ultra-thin 0.5 oz constructions that can’t carry the current and standard 1 oz constructions on 1 mil PI that can’t hit the bend radius. Working on DuPont PCB projects in this space? LF7002R is worth evaluating as the flex core wherever the stackup height and bend constraints are tight.
Camera flex interconnects — Miniaturized camera modules in smartphones, laptops, and automotive vision systems use single-sided flex interconnects where total package thickness is constrained by the optical stack and enclosure. LF7002R’s thin 0.5 mil PI core helps minimize the total circuit cross-section while maintaining adequate copper weight for image sensor data and power traces.
Hearing aids and audiology devices — Among the most size-constrained flex circuit applications in medical electronics. The total circuit volume budget for a hearing aid flex interconnect is measured in fractions of a cubic centimeter. LF7002R’s thin dielectric and RA 1 oz copper combination is a natural fit for this application class.
Flexible antenna substrates with current routing — Flex circuits that incorporate both an antenna element and a power trace benefit from LF7002R when the antenna geometry demands the thinnest possible substrate and the power rail needs real current capacity.
Display and module interconnects in thin device form factors — Tablets, e-readers, and slim laptops use flex circuits to connect display drivers and main boards in enclosures where every 0.1 mm of flex circuit thickness affects the final product profile. A thinner PI core directly contributes to a thinner product.
LF7002R vs. Adhesiveless Single-Sided Alternatives
Pyralux AC and similar all-polyimide adhesiveless laminates produce thinner total circuit constructions by eliminating the adhesive bonding layer entirely. Copper is cast directly onto the polyimide, removing 0.5–1 mil of adhesive from the stack, and the resulting laminate has higher copper peel strength, better dimensional stability, and a higher service temperature ceiling.
For the majority of consumer and industrial applications where the acrylic adhesive system’s service temperature is acceptable, LF7002R provides comparable thin-substrate behavior at lower cost and on a process that fabricators already know. The engineering upgrade to adhesiveless construction makes sense when temperature requirements exceed the acrylic adhesive ceiling (approximately 150°C continuous), when dimensional stability under repeated thermal cycling is a primary specification, or when chip-on-flex assembly requires the tighter copper-to-substrate bond strength that cast adhesiveless constructions deliver.
Useful Resources for Engineers and Procurement
- DuPont Pyralux LF Official Product Page: dupont.com/electronics-industrial/pyralux-lf.html — full product matrix, datasheet downloads, and representative contacts
- Pyralux LF CCL Data Sheet (PDF, EI-10117): The authoritative DuPont document for all LF single-sided and double-sided grade construction data, electrical properties, and laminating parameters — available via DuPont directly or through Insulectro and other authorized distributors
- IPC-4204 Standard: “Flexible Metal-Clad Dielectrics for Use in Fabrication of Flexible Printed Wiring” — the certification standard framework; confirm LF7002R certification status directly with DuPont
- IPC-2223: “Sectional Design Standard for Flexible Printed Boards” — the reference document for bend radius calculations, trace layout rules in flex zones, and stiffener design guidance cited in this article
- IPC-2152: “Standard for Determining Current Carrying Capacity in Printed Board Design” — the basis for trace current calculations at 1 oz copper weight
- IPC-TM-650 Test Methods: Electrical, mechanical, and thermal test methods referenced in Pyralux LF data sheets — available at IPC.org
- Pyralux Flexible Composites Technical Manual: DuPont’s comprehensive processing and fabrication guide — request from your local DuPont representative or authorized Pyralux distributor
- DuPont Safe Handling Guide for Pyralux: Available at pyralux.dupont.com — drilling, routing, chemical handling, and storage procedures
Frequently Asked Questions About DuPont Pyralux LF7002R
Q1: What is the main difference between LF7002R and LF7012R? The copper weight. LF7012R uses 0.5 oz copper (approximately 17.5 µm); LF7002R uses 1 oz copper (approximately 35 µm). Both use the same 0.5 mil Kapton PI core and 0.5 mil acrylic adhesive. The practical impact: LF7002R carries roughly double the current at the same trace width but is slightly less flexible due to the heavier copper layer. Choose LF7012R when minimizing total thickness and maximum compliance are the priority; choose LF7002R when current capacity at 1 oz is required alongside a thin PI substrate.
Q2: Is LF7002R suitable for dynamic flex applications? The RA copper designation makes it suitable for dynamic flex in principle. However, 1 oz copper is at the heavier end for high-cycle dynamic flexing — thinner copper (0.5 oz or less) is preferred for thousands of flex cycles because lighter foil develops fatigue cracks more slowly. For moderate-cycle dynamic applications or installation-time forming with occasional flexing in service, LF7002R with RA copper is appropriate. For aggressive cycle counts, calculate minimum bend radius carefully per IPC-2223 and validate with fabricator flexure testing.
Q3: Why is LF7002R not IPC-4204/1 certified, and does that matter for my design? Per the DuPont LF product table, LF7002R does not carry IPC-4204/1 certification in the standard published listing. Whether that matters depends on your customer’s requirements. Military, aerospace, and certain medical OEM specs may require IPC-4204/1 certified materials throughout the flex stackup. Commercial consumer electronics rarely mandate it. If IPC-4204/1 is a hard requirement, evaluate LF7011R (1 oz / 0.5 mil PI / 1 mil adhesive — IPC-certified) as the nearest alternative with certification.
Q4: What stiffener material should I use with LF7002R? FR4 stiffener (0.062 in / 1.6 mm is standard) is the most common and cost-effective choice for component mounting areas and connector landings. Polyimide sheet stiffeners are a better match for thermal cycling environments where CTE mismatch between FR4 and the PI circuit is a concern. Stainless steel stiffeners are used in applications requiring the stiffest, thinnest possible support. In all cases, position the stiffener edge at least 1.0 mm from the bend tangent and apply strain relief epoxy at the edge in vibration-sensitive assemblies.
Q5: Can LF7002R be used as the flex core in a rigid-flex construction? Yes — single-sided LF grades are used as flex cores in rigid-flex assemblies, where the flexible zone connects rigid cap layer sections. In a rigid-flex application, LF7002R’s thin PI core reduces the total flex zone thickness, which is beneficial in products where the flex zone must route through a tight-radius mechanical transition. Confirm the full rigid-flex stackup with your fabricator during DFM review, particularly the adhesion compatibility between LF7002R and the rigid cap laminate or bondply materials.
Why LF7002R Earns a Place on Your Shortlist
DuPont Pyralux LF7002R is a precision specification for a well-defined engineering problem: 1 oz current-carrying capacity on a dielectric substrate that’s as thin as the LF single-sided family supports. It’s not the default grade — that role belongs to heavier-PI, IPC-certified constructions like LF8022R or LF7011R. But for designs where total stackup thickness and minimum bend radius are genuinely binding constraints, and where dropping to 0.5 oz copper would require trace widths that compromise routing density or current delivery, LF7002R resolves the tension cleanly. Spec it with eyes open on the IPC certification status, plan the fabrication process around the thin PI handling requirements, and it will perform exactly as the construction suggests.
