Many designers and manufacturers wonder whether to apply solder mask on custom Rogers RO3003 high-frequency PCB. Unlike conventional FR-4 boards, standard solder mask coating is generally not recommended for RO3003 RF circuits. This common industry practice is not arbitrary. It targets the unique material properties and high-frequency working characteristics of RO3003 ceramic-filled PTFE laminates.
The biggest downside of solder mask lies in changed dielectric parameters. RO3003 high-frequency PCB features an ultra-stable Dk of 3.00 and ultra-low Df of 0.0010 at 10GHz, delivering minimal signal loss for microwave and mmWave circuits. Commercial solder mask ink has mismatched dielectric constants. Coating it on RF transmission lines will alter the original impedance design. It causes unstable dielectric superposition and increases high-frequency signal attenuation, directly undermining the high-precision performance of 77GHz automotive radar and 5G mmWave modules.
Solder mask coating also brings uncontrollable thickness tolerance risks. Standard PCB solder mask printing cannot guarantee uniform coating thickness on RO3003 board surfaces. Tiny thickness differences will lead to inconsistent impedance values across different board batches. For mass-produced high-frequency RF PCB products, this variation causes unstable signal transmission and poor product consistency. It greatly raises the failure rate of high-sensitivity communication and radar equipment.
In addition, RO3003 PTFE substrate has poor solder mask adhesion. The smooth and inert surface of ceramic-filled PTFE materials makes it hard for solder mask ink to form a firm bond. Long-term high-frequency operation and temperature cycling will easily cause mask peeling, warping and edge cracking. Falling solder mask residues may trigger circuit short circuits or signal distortion, severely affecting the long-term reliability of industrial RF PCB.
For these reasons, professional fabricators usually adopt bare copper surface treatment or specialized thin protective coating for RO3003 high-frequency PCB. This method fully preserves the original dielectric stability of Rogers RO3003 material. It ensures consistent impedance control and ultra-low signal loss, perfectly matching the performance requirements of high-end microwave communication and automotive radar PCB applications.
Rogers RO3003 Standard Material Specification Parameters
The table below lists official standard technical parameters of Rogers RO3003 high-frequency PCB laminate, covering electrical, thermal, mechanical and application indicators for accurate RF PCB design and manufacturing reference.
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參數類別
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技術項目
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典型值
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測試條件與標準
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|---|---|---|---|
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電學性質
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介電常數 (Dk)
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3.00 ± 0.04
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10GHz，IPC-TM-650
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損耗因數 (Df)
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0.0010
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10GHz, ultra-low loss performance
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體積電阻率
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1.6×10¹⁰ MΩ·cm
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Standard atmospheric condition
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表面電阻率
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3.8×10⁹ MΩ
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Room temperature environment
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介電擊穿強度
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480 V/mil
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Insulation performance test
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熱學特性
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玻璃轉變溫度 (Tg)
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＞280°C
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TMA testing standard
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熱導率
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0.50 W/m·K
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50°C, ASTM D5470
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XY/Z-axis CTE
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17/16/25 ppm/°C
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-55°C~288°C, IPC-TM-650 2.4.41
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熱分解溫度 (Td)
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380°C
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Long-term thermal stability
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機械性能
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銅材剝離強度
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12.7 lbs/in
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1oz EDC copper, after solder float
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彎曲強度
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240 MPa
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IPC-TM-650 standard test
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吸濕性
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0.04%
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48h humid environment test
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安全等級
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阻燃等級
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UL 94 V-0
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Industrial fire resistance standard
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應用範圍
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工作頻率
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Up to 79GHz
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Suitable for mmWave radar and microwave RF circuits
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These ultra-stable parameters explain why custom RO3003 high-frequency PCB is extremely sensitive to solder mask coverage. Its precise Dk/Df values and matched copper CTE ensure minimal signal loss, while additional solder mask coating will destroy the original electrical consistency and ruin high-frequency circuit performance.
