If MOS FET relays are mounted and soldered on PCBs with semiconductor devices, can the relays be cleaned with the same conditions as those for semiconductor devices? What are the cleaning conditions, and can ultrasonic cleaning be applied to them?

MOS FET relay cleaning

• Precautions in flux cleaning
  
  1. Flux cleaning should be performed so that there are no residual reactive ions such as sodium and chlorine.
     Some organic solvents react with water and generate corrosive gases such as hydrogen chloride, which may cause　degradation of MOS FET relays.
  2. When washing with water, ensure that there are no residual reactive ions such as sodium and chlorine.
  3. Do not rub the display mark surface with a brush or hand while cleaning or while cleaning fluid is attached to the MOS FET relay. Doing so may erase the display mark.
  4. Immersion, shower, and steam cleaning uses chemical action of the solvent to clean. In consideration of the effect on the MOS FET relays, the immersion time in solvent or steam should be within 1 minute at a liquid temperature of 50°C or lower.
• Precautions on ultrasonic cleaning
  Ultrasonic cleaning, if needed, must be performed in a short amount of time. Cleaning for a long time may reduce the adhesion between the mold resin and the frame material. Shown below are recommended basic conditions for ultrasonic cleaning:
  
  • Frequency: 27 to 29 kHz
  • Ultrasonic wave output: 300 W max .(0.25 W/cm2 max.)
  • Cleaning time: 30 seconds max.
  • *Make sure that the ultrasonic vibrator and the PCB or MOS FET relay are suspended in the solvent to prevent direct contact with each other.

For more information, see Common Precautions for All MOS FET Relays: Cleaning Flux from the MOS FET Relays.

Cleaning residue may cause insulation degradation and terminal corrosion. Check the cleaning conditions before cleaning.
Note that ultrasonic cleaning should be performed in a short amount of time.