Rogers RT/duroid 5880 FR-4 4-Layer 1.0mm High Frequency RF Microwave PCB ENIG

1.Introduction to RT/duroid 5880 + FR-4 4-Layer Hybrid PCB

This 4-layer copper (6-layer structure) rigid hybrid PCB is constructed with Rogers RT/duroid 5880 and High Tg FR-4 as the base materials. RT/duroid 5880 is a glass microfiber reinforced PTFE composite designed for exacting stripline and microstrip circuit applications. The randomly oriented microfibers result in exceptional dielectric constant uniformity. The dielectric constant of RT/duroid 5880 laminates is uniform from panel to panel and is constant over a wide frequency range. Its low dissipation factor extends the usefulness of RT/duroid 5880 laminates to Ku-band and above. The board features immersion gold (ENIG) surface finish with 2 microinches gold thickness, blue solder mask, white silkscreen, 25μm via plating thickness, IPC-Class-3 quality standard, and controlled depth routing. The finished board thickness is 1.0mm with board dimensions of 90mm x 80mm.

2.Key Features of RT/duroid 5880

Dielectric constant (process): 2.20 ±0.02 at 10 GHz / 23°C
Dielectric constant (design): 2.20 at 8 to 40 GHz
Dissipation factor: 0.0004 at 1 MHz, 0.0009 at 10 GHz / 23°C
Thermal coefficient of Dk: -125 ppm/°C (-50 to 150°C)
Volume resistivity: 2 x 10⁷ MΩ·cm (C96/35/90)
Surface resistivity: 3 x 10⁷ MΩ (C96/35/90)
Specific heat: 0.96 J/g/K (0.23 cal/g/°C)
Tensile modulus X at 23°C: 1,070 MPa (156 kpsi)
Tensile modulus Y at 23°C: 860 MPa (125 kpsi)
Tensile strength X at 23°C: 29 MPa (4.2 kpsi)
Tensile strength Y at 23°C: 27 MPa (3.9 kpsi)
Moisture absorption: 0.02% (0.062" sample, D48/50)
Thermal conductivity: 0.20 W/m/K at 80°C
CTE X-axis: 31 ppm/°C (0-100°C)
CTE Y-axis: 48 ppm/°C (0-100°C)
CTE Z-axis: 237 ppm/°C (0-100°C)
Td: >500°C (TGA method)
Density: 2.2 g/cm³
Copper peel strength: 5.5 N/mm (31.2 pli) for 1 oz EDC foil after solder float
Flammability rating: UL 94 V-0
Lead-free process compatible: Yes

3.Benefits of This 4-Layer Hybrid PCB

RT/duroid 5880 glass microfiber reinforced PTFE provides exceptional dielectric constant uniformity
Low dissipation factor (0.0009 at 10 GHz) extends usefulness to Ku-band and above
Dk is constant over a wide frequency range
Uniform Dk from panel to panel for consistent performance
Resistant to all solvents and reagents used in etching printed circuits or plating edges and holes
Easily cut, sheared and machined to shape
CTE matched designs possible with hybrid FR-4 construction
ENIG surface finish with 2μ" gold provides excellent solderability and corrosion resistance
IPC-Class-3 quality for high-reliability applications
Controlled depth routing for precise mechanical features

4.RT/duroid 5880 + FR-4 4-Layer Hybrid PCB Construction Details

5.PCB Stackup (4-Layer Rigid PCB)

L1 Copper: 0.035 mm
Core RT/duroid 5880: 0.254 mm
Copper: 0.018 mm
Prepreg 2116 (RC53%) x 1: 0.12 mm
Core FR-4: 0.1 mm
Prepreg 2116 (RC53%) x 1: 0.12 mm
Copper: 0.018 mm
Core FR-4: 0.254 mm
L4 Copper: 0.035 mm

Pressed thickness: 0.954 mm

6.Primary Application Areas

Stripline and microstrip circuit applications
Aerospace and defense systems
Satellite communication systems
Radar systems
Millimeter wave applications
Ku-band and above applications

7.Quality Assurance

Artwork supplied: Gerber RS-274-X
Accepted standard: IPC-Class-2
Availability: Worldwide

8.RT/duroid 5880 High-Frequency Laminate – Product Introduction

RT/duroid 5880 glass microfiber reinforced PTFE composites are designed for exacting stripline and microstrip circuit applications. The randomly oriented microfibers result in exceptional dielectric constant uniformity. The dielectric constant of RT/duroid 5880 laminates is uniform from panel to panel and is constant over a wide frequency range. Its low dissipation factor extends the usefulness of RT/duroid 5880 laminates to Ku-band and above. RT/duroid 5880 laminates are easily cut, sheared and machined to shape. They are resistant to all solvents and reagents, hot or cold, normally used in etching printed circuits or in plating edges and holes. Normally supplied as a laminate with electrodeposited copper of ½ to 2 ounces per square foot on both sides, RT/duroid 5880 composites can also be clad with rolled copper foil for more critical electrical applications. Cladding with aluminum, copper or brass plate may also be specified.

9.Features and Benefits of RT/duroid 5880

Benefits:
Exceptional dielectric constant uniformity from panel to panel
Dk constant over wide frequency range
Low dissipation factor for high frequency performance to Ku-band and above
Easily cut, sheared and machined to shape
Resistant to all solvents and reagents used in PCB fabrication
Multiple cladding options available (EDC copper, rolled copper, aluminum, brass, copper plate)

RT/duroid 5880 Data Sheet

11.Some Typical Applications

Stripline and microstrip circuit applications
Aerospace and defense systems
Satellite communication systems
Radar systems
Millimeter wave applications
Ku-band and above applications

12.What is Controlled Depth Routing?

Controlled depth routing is a precision machining technique used in PCB fabrication to route or mill to a specific depth without cutting through the entire board thickness. This allows for the creation of cavities, step cuts, or partial cutouts in the PCB. In this product, controlled depth routing is incorporated for precise mechanical features.

13.Fabrication Guidelines for RT/duroid 5880:

Storage: RT/duroid laminates can be stored indefinitely at normal ambient room temperatures (65°F to 85°F, 18°C to 30°C) and humidity levels. At room temperature, the dielectric materials are inert to high humidity.

Handling: PTFE-based materials are softer than most other rigid printed wiring board laminates and are more susceptible to handling damage. Gloves should be worn when handling panels.

Drilling: Carbide drills should be used. Standard style drills with an included lip angle of 130° are recommended. Optimum tool surface speed is 150 to 250 surface feet per minute with infeed rates of 0.0015" to 0.0025" per revolution. Drilled holes must be treated prior to deposition of a conductive seed layer. Sodium treatment is the preferred option for treating RT/duroid 5880 materials.

Hole Preparation: Sodium treatments consist of a highly reactive sodium napthalene complex in glycol ether solution. They are very effective at making PTFE surfaces wettable prior to metal deposition. Plasma treatment may be used for direct metallization processes.

Metallization: Low to regular deposition rate electroless copper processes may be used once the PTFE surface has been properly treated.

Final Metal Finishes: All final metal surface options (i.e. HASL, Sn, Sn/Pb, Ni/Au, Ag, OSP, etc.) can be applied using normal procedures.