Introduction
Printed circuit boards (PCBs) are essential components in nearly all modern electronics. As devices continue getting faster and more complex, the PCBs inside them must keep up. This means using the most advanced materials and manufacturing processes available. One vital material for cutting-edge PCBs is copper clad laminate (CCL). Rogers Corporation’s CuClad 233 is one of the premier CCLs on the market for high frequency applications requiring low loss, tight impedance control, and consistent performance.
What is Rogers CuClad 233?
Rogers CuClad 233 is a glass reinforced, ceramic filled fluoropolymer composite laminate clad with electrodeposited copper foil on both sides. The dielectric material provides excellent electrical performance and stability while the copper foil enables fine line etching and reliable connections.
Some key properties and benefits of CuClad 233 include:
- Low dielectric constant and loss for high frequency signal integrity
- Stable electrical properties over frequency, temperature, and bias
- Tight impedance control and consistent propagation delay
- High peel and bond strengths maximize manufacturability
- Lead-free compatible and RoHS compliant
CuClad 233 Applications
CuClad 233 is optimized for controlled impedance boards for high speed digital and RF applications including:
- Data communication systems
- Telecommunication infrastructure
- Cellular base stations
- Radar and satellite communication
- Test and measurement equipment
- Aerospace and defense electronics
It is used to fabricate multilayer PCBs with impedance requirements up to 30 GHz for stripline and microstrip transmission structures. The consistent electrical properties enable accurate modeling and reliable system performance.
Key Applications
Some major applications taking advantage of CuClad 233 include:
- High speed backplanes
- Microwave antennas and filters
- Radar phase shifters
- Digital data processing
- Wideband communication
- Test fixtures
CuClad 233 Material Properties
Rogers utilizes advanced dielectric materials technology to create laminates like CuClad 233 with exceptional properties. Here are some of the key material properties:
Electrical Properties
| Property | Value |
|---|---|
| Dielectric Constant (10 GHz) | 2.33 |
| Dissipation Factor (10 GHz) | 0.0012 |
| Dielectric Breakdown Voltage | >1.5 kV |
Physical Properties
| Property | Value |
|---|---|
| Specific Gravity | 1.85 |
| Moisture Absorption | <0.04% |
| Coefficient of Thermal Expansion | 17 ppm/°C |
| Glass Transition Temperature | >280 °C |
Key Material Features:
- Low loss for high frequency performance
- Controlled dielectric constant for consistent impedance
- High breakdown strength for reliability
- Low moisture absorption prevents electrical instability
- Matched coefficients of expansion with copper for reliability
CuClad 233 Fabrication
To fully leverage the advanced electrical and physical properties of CuClad 233 requires utilization of proper fabrication processes. Here are some key guidelines for working with CuClad 233:
Inner Layer Formation
- Use reverse treat electrodeposited copper foils for high bond strength
- Select glass fabric styles like 1078 or 1067 for ease of processing
- Optimize lamination cycles for void-free uniform lamination
Patterning
- Employ alkaline etching to achieve fine features and high aspect ratios
- Use plasma processes for anisotropic etching
- Maintain proper sidewall roughness parameters
Outer Layer Processing
- Apply oxide treatment to drilled holes for adhesion and RMS
- Exercise control over copper plating thickness and morphology
- Apply solder masks compatible with the material and application
Final PWB Finishing
- Allow sufficient bake out time after solder mask curing to eliminate moisture
- Use rack process for higher reliability compared to panel plating
- Apply appropriate surface finishes like ENIG, immersion Ag, or OSP
Careful attention to PWB processing is necessary to achieve electrical performance that matches modeling predictions.
Modeling and Analysis
To fully optimize a PCB design using CuClad 233, accurate modeling and simulation is essential. Some key considerations include:
- Use dielectric constant and loss tangent values appropriate for frequency range of interest
- Model conductor surface roughness to capture associated losses
- Account for frequency dependent conductor losses
- Model effects of laminate inhomogeneity and anisotropy
- Validate models through comparison with measured data
Modeling Software
Many commercial software packages are available for modeling circuit boards using CuClad 233 properties including:
- Ansys SIwave – Provides a 3D planar EM simulator for analyzing signal integrity, power integrity, and EMI on high speed PCBs. Enables simulation from DC to 40+ GHz.
- Keysight ADS – Features 2D and 3D EM simulation modules with integrated circuit design tools. Allows analysis of component interactions from DC to microwave frequencies.
- Cadence Allegro PCB Editor – Includes analysis tools like physical constraint manager, signal and power integrity, and EMI modeling. Allows simulation of flexible and rigid-flex PCBs.
Proper modeling ensures designs meet target impedance, loss, and propagation delay requirements when fabricated.
Rogers PCB Technology Leadership
Rogers Corporation has been leading innovation in printed circuit board materials for over 35 years. Some technology achievements include:
- First high frequency circuit materials using PTFE composites
- First commercial high frequency laminates using ceramic filler polymers
- First halogen-free/lead-free laminate materials
- Development of world’s lowest loss production laminates
Rogers’ materials expertise combined with extensive modeling and measurement capabilities enables the development of cutting edge PCB solutions like CuClad 233.
Conclusion
As communication systems increase in complexity and speed, having the right PCB materials is critical. Rogers CuClad 233 provides an optimal combination of electrical performance, stability, and manufacturability for fabricating impedance controlled circuits up to 30 GHz and beyond. When paired with accurate modeling and simulation techniques, designs can fully leverage the properties of CuClad 233 to enable the next generation of high frequency electronic devices and systems. The unique material properties and consistent performance make CuClad 233 a premier solution for high speed digital and RF PCB applications.
Frequently Asked Questions
What are some key benefits of using CuClad 233?
Some of the major benefits of CuClad 233 include:
- Low loss and tight impedance control for high frequency applications
- Stable electrical properties over wide frequency and temperature ranges
- High peel and bond strengths for manufacturability and reliability
- Lead-free compatible and RoHS compliant
- Allows fabrication of circuits with impedance control up to 30 GHz
What fabrication processes are important for working with CuClad 233?
Key fabrication considerations include:
- Using reverse treat electrodeposited copper foils
- Selecting compatible glass weave styles like 1078
- Employing void-free lamination processes
- Optimizing drilling and plating processes
- Using appropriate solder masks compatible with the material
- Allowing for proper bake out time after processing to eliminate moisture
What modeling software can be used for CuClad 233 PCB design and analysis?
Some leading modeling software options for CuClad 233 include:
- Ansys SIwave for 3D planar EM simulation from DC to 40+ GHz
- Keysight ADS for 2D/3D EM simulation with integrated circuit design tools
- Cadence Allegro PCB Editor for analysis like signal integrity and EMI modeling
What are some typical applications for CuClad 233?
Typical applications include:
- High speed backplanes
- Microwave antennas and filters
- Radar phase shifters
- Digital data processing
- Test fixtures
- Aerospace and defense electronics
How does CuClad 233 enable next generation high frequency PCBs?
CuClad 233 provides the electrical performance and stability needed for emerging applications like 5G communications, high speed computing, and radar systems. The low loss, matched expansion to copper, and tight impedance control allow circuit fabrication with accurate modeling up to 30 GHz and beyond.
