简介：PC-600 ACID COPPER PLATING PROCESS
PC-600 ACID COPPER PULSE PLATING PROCESS
PC-600 is an acid copper plating additive system that has been specifically optimized for use with pulse periodic reverse rectification on a continual production basis.
READ ENTIRE TECHNICAL DATA SHEET BEFORE USING THIS PRODUCT
FEATURES & BENEFITS
The process produces a fine-grained, ductile deposit with excellent distribution characteristics, and is maintained with two components. The combination of PC-600 and a periodic reverse pulse plating rectifier can significantly shorten plating times while maintaining excellent distribution ratios.
Nominal Deposit Characteristics
Electrical Resistivity 1.68 micro-ohm-cm
Elongation* Greater than 18%
Internal Stress 750 to 1500 psi
Density 9 g/cc
Ultimate Tensile Strength* Greater than 36,000 psi
Microscopic Structure Fine Grained Equiaxed
*Testing per IPC-TM-650, Method 18.104.22.168
PROCESS COMPONENTS REQUIRED
Tanks, pipes, fittings and valves should be acid resistant. All plastic parts should be of Teflon?, PVC, PVDF, polypropylene or high-density polyethylene construction. Soft PVC (e.g. Tygon?) is not recommended for constant contact with the bath.
Anode bars, cathode bars and bus bars should be made of copper. Bolts, fixtures, etc. that are not immersed in the plating solution may be made of copper, bronze, 316 stainless steel or titanium. Metal parts that will be immersed in the plating bath should be constructed of titanium.
Acid copper sulfate solutions are corrosive. It is important to protect the floors, plumbing and any other equipment, which may come in contact with the plating solution. Vinyl coatings, asphalt or several coats of rubber-based paint will usually provide adequate protection.
Rectifier output (amperage) should be calibrated to 土5% or less across the working range. Also the pulse wave form (especially the % overshoot and rise time) should be checked with an oscilloscope by a qualified technician.
The preferred rack materials are copper and copper alloys. The rack area, if immersed in plating solution, should be coated with a non-conductive material (e.g. Plastisol?, Koroseal?).
MAKE UP PROCEDURE
Copper Sulfate Pentahydrate 65 g/L**
Sulfuric Acid 12.7% by volume (230 g/L H2SO4)
PC-600 Carrier 3% by volume
PC-600 Replenisher 0.20% by volume
Deionized Water Balance
Chloride 70 ppm
Note: COPPER SULFATE CONCENTRATE from MacDermid Enthone typically contains about 270 g/L (36 oz/gal) of copper sulfate pentahydrate, or 68.7 g/l (17.5 oz/gal) of copper metal.
1. Fill to half of final working volume with deionized water.
2. With mixing, add the required amount of copper sulfate and dissolve.
3. With heavy mixing, slowly add the required amount of sulfuric acid. The addition of sulfuric acid produces a considerable amount of heat. If PVC structures are present, monitor the temperature of the solution and do not allow it to exceed 49 °C (120 °F).
4. Cool, with mixing, to 29 °C (85 °F).
5. Add 0.41 g/L of Manganese Sulfate monohydrate pre-dissolved in DI water (CAS #10034?96-5, tech grade or better).
6. With mixing, add the required amounts of PC-600 Carrier and PC-600 Replenisher.
7. Fill to final volume with deionized water and mix.
8. Check the chloride content of the bath and add sufficient hydrochloric acid to raise the chloride to approximately 80 ppm.
(ppm chloride add desired) (bath volume in liters)/425 = mLs of 37% (concentrated HCI to add
Electrolyze (dummy plate) the bath for 3 hours at 20 ASF (2 ASD) while maintaining the brightener concentration by CVS, CPVS or dilution Hull cell (the feed rate of PC-600 Replenisher should be about 0.2 to 0.5 mL/amp. hr, however, the initial feed rate for the first day may be higher). The PC-600 Carrier feed rate should be about 0.2 to 0.5 mL/amp. hr. The pulse waveform should be set at 40 msec forward; 2.3 msec reverse and a 2 to 1 reverse current ratio. Plate a test panel and obtain cross-section results to be sure the optimum performance is obtained before starting production. Some plating tank or board designs may require special waveforms or brightener concentrations in order to obtain optimum results.
The operating conditions for the PC-600 Acid Copper process are as follows:
Parameter Range Target
Copper Sulfate 55 to 75 g/L 7.3 to 10 oz/gal 65 g/L 8.6 oz/gal
Sulfuric Acid 215 to 245 g/L 12 to 13.5% by volume 230 g/L 12.75% by volume
Chloride 50 to 90 ppm 70 ppm
PC-600 Carrier 1 to 5% by volume 3% by volume
PC-600 Replenisher 0.05% to 0.35% by volume 0.20% by volume
Temperature 21 to 27 °C 70 to 80 °F 24 °C 75 °F
Forward Cathode Current Density 8 to 25 ASF 0.86 to 2.7 ASD 17 ASF 1.8 ASD
Pulse cycle Forward Time: 40 milliseconds Reverse Time: 2.3 milliseconds Reverse CD Ratio: 2 to 1
(Pulse cycle can vary depending on plating operation.)
Agitation Air or eductors (eductors preferred) and cathode rod
Filtration Continuous, 2 to 3 turnovers per hr (1 micron polypropylene filter is recommended.)
Anodes Phosphorized copper (0.03 to 0.08% phosphorous).
Anode Baskets Titanium (square baskets with nuggets is recommended).
Anode Hooks Titanium
Anode bags Polypropylene (cotton and other cellulose based materials are unacceptable)
MAINTENANCE AND REPLENISHMENT
The copper, sulfuric acid, and chloride content of the acid copper plating solution are analyzed using the analytical procedures that are included in this data sheet. The PC-600 Carrier and PC-600 Replenisher concentrations are controlled by proprietary CPVS and or CVS procedures (as well as specially prepared Hull cell methods). Please refer to the separate control procedure bulletins for these methods or consult your technical service representative.
All new anode bags and filters should be leached before use in an acid copper plating bath.
The materials should be leached in hot water (43 to 71 °C, 110 to 160 °F) with changes of water until fresh leach water no longer foams. The initial leach can be augmented by the addition of 3% sulfuric acid.
The anode current density should be maintained between 10 and 30 ASF (0.93 to 2.8 ASD) in general operation. Excessive
Anode current density can lead to anode polarization and poor deposit distribution and structure.
Anode to cathode distance spacing is also important in the general operation of an acid copper-plating bath. An anode to cathode distance of 20 to 30 cm (8 to 12 inches) is recommended to insure a more uniform distribution of the deposit.
It should be noted that anode and cathode placement, agitation, copper concentration, temperature, electrical connection and circuit configurations could affect distribution and usable current density range. More details of these effects can be found in the attached troubleshooting guide.
The optimum temperature for most situations is 24 °C (75 °F) with a range of 21 to 27 °C (70 to 80 °F). Low temperatures may cause burning.
FUNCTION OF BATH COMPONENTS
Copper Sulfate Content
Copper sulfate provides copper ions for the deposition process. It should be maintained within the specified limits of 55 to 75 g/L. Higher levels give no advantage at 30 ASF but may help increase leveling at higher current densities. Lower concentrations will reduce maximum operating current density but can give improved metal distribution.
Sulfuric acid provides solution conductivity. It should be maintained between 12 to 13.5% by volume. Higher concentrations may lead to anode polarization. Low concentrations may degrade deposit distribution.