Rogers Corporation aims to provide high-performance laminates with integrated resistive foils that meet rigorous electrical and aesthetic standards for precision circuit fabrication. This statement outlines the key characteristics of resistive foil products, including visual appearance and resistivity performance.

Visual Appearance of Resistive Foil

Surface Features

• Normal Variations:
  Resistive foils may exhibit minor surface features such as slight discoloration, streaks, or patterns resulting from the manufacturing process. These are normal and do not affect the electrical performance or adhesion properties.
• Inspection Standards:
  Visual inspection of resistive foils is performed under standard lighting conditions. Imperfections that do not interfere with resistivity or processing are considered acceptable.

Protective Film:

• Foils are often shipped with a protective layer to prevent contamination and damage during handling. This film should remain intact until processing begins.

Cleanliness:

• Ensure the resistive foil surface is free of fingerprints, dust, or oils before starting any processing steps to maintain resistive performance.

Resistivity Expectations

Sheet Resistance

• Resistive foils are supplied with nominal sheet resistances such as 25, 50, or 100 Ω/□, with a tolerance typically specified in the product data sheet.

Uniformity

• Across Laminate:
  The resistive layer is engineered to maintain consistent sheet resistance across the entire laminate surface. Variations, if present, are within acceptable industry standards.
• Temperature Stability:
  The temperature coefficient of resistance (TCR) is typically ±100 ppm/°C, ensuring stable performance across a range of operating temperatures.

Long-Term Stability

• Resistive foils are designed for long-term reliability, with minimal resistance drift under normal operating conditions.

Measurement Guidelines:

• Use a 4-point probe to accurately measure sheet resistance.
• Measurements should be conducted under controlled conditions to avoid discrepancies caused by temperature or environmental factors.

Common Processing Considerations

1. Handling:
   • Use clean, lint-free gloves to prevent contamination.
   • Avoid mechanical damage that could affect resistive properties.
2. Lamination:
   • Maintain uniform pressure and temperature during lamination to ensure consistent foil adhesion.
3. Resistor Trimming:
   • Laser or chemical trimming may be used for precision resistance adjustments without compromising stability.

Performance Testing and Guarantees

Rogers Corporation performs rigorous testing to ensure resistive foils meet the following standards:

• Adherence to specified resistivity tolerances.
• Durability under thermal cycling and high-frequency operation.
• Reliability in high-performance and high-reliability applications, including aerospace and defense.