Rogers Corporation provides high-quality resistive foils, such as TICER® TCR thin-film resistor foils, as part of its laminate offerings. These foils are designed for applications requiring precision resistive elements in high-frequency, RF, and microwave circuits. The following statement clarifies the expectations for the visual appearance and electrical performance of resistive foils.

1. Visual Appearance of Resistive Foils

Resistive foils may exhibit variations in visual appearance due to the manufacturing process, storage, or handling. These variations typically include:

• Color Changes: Slight discoloration or mottling is normal and does not affect performance.
• Surface Marks: Minor scratches, streaks, or tooling marks may be present but should not extend through the resistive layer.
• Oxidation: A light oxidation layer is common and can be removed during the standard PCB cleaning process.

Note: Visual variations are purely cosmetic and do not impact the foil’s resistivity or functionality.

2. Resistivity Expectations

Resistive foils are manufactured to meet precise sheet resistivity values and tolerances.

Sheet Resistivity

• Standard Values: 10 Ω/sq, 25 Ω/sq, 50 Ω/sq, and custom values on request.
• Tolerance: ±10% of the nominal value.

Temperature Coefficient of Resistance (TCR)

• Value: Typically ±200 ppm/°C.
• Performance: Maintains stable resistance over operating temperature ranges.

3. Quality Assurance

All resistive foils undergo rigorous testing to ensure they meet Rogers’ high standards for:

• Resistivity: Verified across multiple sample points per sheet.
• Adhesion Strength: Ensures reliable bonding to laminate substrates.
• Durability: Validated under environmental and thermal stress conditions.

4. Handling and Storage Recommendations

Proper handling and storage are crucial to maintain the performance of resistive foils:

• Storage Environment:
  • Temperature: 23°C (73°F).
  • Humidity: ≤50%.
  • Avoid exposure to extreme conditions or direct sunlight.
• Handling Precautions: Use gloves to prevent contamination or oils from hands.
• Cleaning: Remove oxidation or residues before processing using standard micro-etch solutions.

5. Customer Considerations

• Pre-Processing Inspections: Rogers recommends inspecting foils for any defects before use.
• Performance Validation: Measure sheet resistivity after cleaning and prior to lamination to ensure conformance.
• Custom Specifications: For applications requiring tighter tolerances or unique resistivity values, contact Rogers for customized solutions.