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MAR CT-74

MAR CT-74 provides a minute, highly charged colloid which promotes a uniform, highly adherent electroless copper deposit. CT-74 is a very stable chemistry with a low halogen content which minimizes copper attack and produces an absorbent palladium deposit.

Advantages of the MAR CT-74 process include:
  • Less decay of the catalyst providing a longer process life
  • The MAR CT-74 has a low halogen content which provides a more stable solution than sulfate based systems.
  • Deposits small colloid structure which will produce a dense electroless copper deposit.
  • Provides highly active sites of catalyst resulting in a uniform hole wall coverage.
SOLUTION MAKE-UP
DI Water 96% of working bath
MAR CT-74 3%
Hydrochloric Acid 1% of final volume of working bath
PD-70C 240 g/l
  1. Fill tank with 96% of DI water.
  2. Add 1% by volume of Hydrochloric Acid.
  3. Add 240 g/l of PD-70C to the acidified DI water. Mix till PD-70C is totally dissolved.
  4. When pre-dip is finally dissolved, add 3% of CT- 74.
SOLUTION MAINTENANCE

MAR CT-74 should be discarded when copper metal exceeds 1 g/l (1000ppm)

OPERATING PARAMETERS
Optimum Range
MAR PD-70C 240g/l 240g/ l± 24 g/l
Normality 0.80 0.60 – 1.0N
Temperature 30°C 21 - 43°C
Stannous Chloride 17 g/l 15 – 30 g/l
Palladium Metal 0.240 g/l 0.200 – 0.240 g/l
3% 2.50 – 3.00%
Time 5 min 4 – 8 min
Square foot replenishment 0.30 ml/ssf 0.30 – 0.40 ml/ssf

***Analysis to be done daily***

Never add water to catalyst bath. Bath should be replenished with a MAR PD-70C made solution when level drops. Make MAR PD-70 solution using the same make-up listed above without adding MAR CT-74 catalyst.

EQUIPMENT
Tanks: Polypropylene, HD Polyethylene, PVC
Heaters: Teflon, Teflon coated SS, Quartz
Ventilation: Required.
Filtration Recommended. Continuous filtration through a 10 micron polypro filter tube is advisable at 3 to 4tank volume turnovers per hour.
Agitation: Recommended. Work rod agitation to maximize movement of solution through holes is recommended. DO NOT USE AIR AGITATION!!
Vibration: Recommended for small hole and high aspect ratio boards.
ANALYSIS OF STANNOUS CHLORIDE
  1. Reagents Required
    1. 0.1N Iodine solution
    2. Starch Indicator Solution
    3. 250 ml. Erlenmeyer Flask
    4. 50 ml. burette
    5. 5 ml. pipette
  2. Method
    1. Pipette a 5ml sample into a 250ml Erlenmeyer Flask.
    2. Add 100 ml of DI water
    3. Add 2 mls of 2% starch solution
    4. Titrate with 0.1N iodine solution to a blue endpoint which lasts for at least 30 seconds.
  3. Calculation
    1. g/l stannous chloride = mls 0.1N iodine x 2.257

    Maintain between 15 – 30 g/l
Please note that the information above for this chemical is partial. Click the button below to request full technical information sheet.
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