ELECTROPOSIT 1100 B-2 Acid Copper Additive

Transcription

1 Technical Data Sheet ELECTROPOSIT 1100 B-2 Acid Copper Additive For PWB Metallization Applications Regional Product Availability Description Asia The Dow Electronic Materials ELECTROPOSIT 1100 B-2 Acid Copper Additive is designed for reliable through-hole plating of conventional printed circuit boards. Use of the additive can significantly increase productivity while providing excellent leveling, surface distribution, and throwing power when plating through-hole aspect ratios up to 10:1. Dow Electronic Materials can also provide processes for plating through holes with aspect ratios up to 20:1. Contact your Dow Electronic Materials Technical Representative for details. ELECTROPOSIT 1100 B-2 Acid Copper additive is a make-up and replenishment additive system that provides a number of important circuit board fabrication advantages. Advantages Excellent throwing power, surface distribution and leveling at plating rates up to 4.0 A/dm 2 Utilizes conventional equipment Superior thermal shock resistance meets or exceeds MIL-P-55110D Ease of Control Straightforward Hull Cell interpretation Dow ELECTROPOSIT Bath Analyzer for additive component analysis Reduced bath maintenance Bath Make-up Component Metric Deionized Water 450 ml/l Electronic Grade Copper Sulfate (CuSO4 5H20) 80 g/l Purified Liquid Copper Sulfate (270 g/l CuSO4 5H2O) 300 ml/l Sulfur Free Carbon (Powder Norit SX4) or 6 g/l Sulfur Free Carbon (Norit RO 0.8) 9 g/l C.P. Grade Concentrated Sulfuric Acid 225 g/l C.P. Grade Concentrated Hydrochloric Acid (37%) 0.12 ml/l Electroposit 1100 C ml/l Page 1 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

2 Bath Operation Component Range Recommended Electronic Grade Copper Sulfate (CuSO4 5H2O) (60 90 g/l) (80 g/l) C.P. Grade Conc. Sulfuric Acid (spec. grav. of 1.84) % b.v g/l 12.2% b.v 225 g/l Chloride (from HCI) ppm 50 ppm ELECTROPOSIT 1100 B-2 Acid Copper Additive % ml/l 0.75 ml/l Cathode Current Density: A/dm 2 Agitation: Moderate air and paddle agitation Temperature: C Anode to Cathode Ratio*: 1:1 2:1 Anode Current Density*: 2.0 A/dm 2 maximum Anode to Cathode Distance: cm Anodes: Anode Bags: Phosphorized copper ( %P) Napped or unnapped polypropylene Filtration: Continuous through 5 micron filter * Note: Correct current density and ratio are necessary to maintain adherent anode film. Replenishment Schedule Component ELECTROPOSIT 1100 B-2 Acid Copper Additive Addition Rate ml/amp-hr New Bath Installation I. Plating Tank Preparation a) Preparation of a New Plating Tank: Clean plating tank to remove any dirt and flush clean with hot water. Leach with 5% sodium hydroxide for 4 hours. Rinse well deionized water. b) Preparation of an Existing Plating Tank: Discard bath if the tank has previously been used with other acid copper additives. Clean plating tank to remove any debris, scrub tank walls and flush clean with water. Leach overnight with 10% by volume sulfuric acid. Rinse well with deionized water. Note: Wear chemical resistant gloves, goggles and suitable protective clothing when handling sodium hydroxide and sulfuric acid. Preparation of Copper Sulfate/Sulfuric Acid Plating Solution a) Add two-thirds of the required D.I. water to a preparation tank. b) Carefully add the concentrated sulfuric acid slowly and with good mixing to prevent localized overheating of the solution and the possible risk of solution eruption of the sulfuric acid dilution. DANGER! Concentrated sulfuric acid is corrosive to organic tissue and causes severe burns on contact with eyes, skin or mucous membranes. Consult appropriate Material Safety Data Sheet for this material. Page 2 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

3 I c) Add the liquid copper sulfate and mix in with stirring. If copper sulfate crystals are used, be sure to completely dissolve them by stirring. WARNING! Copper sulfate may irritate eyes, skin or mucous membranes. Consult the appropriate Material Safety Data Sheet for this material. Follow the directions above for mixing the components. Consult the appropriate Material Safety Data Sheets before using any commodity chemicals. Preparation of the Plating Bath a) The amount of chloride ion in the solution is very important. Chlorides may already exist as contaminants, therefore analyze for chlorides before addition. Use 37% reagent grade hydrochloric acid (specific gravity of 1.18) to adjust. DANGER! Concentrated hydrochloric acid is very corrosive and causes severe burns on contact with eyes, skin or mucous membranes. Consult the appropriate Material Safety Data Sheet for this material. To raise chloride ion by 10 ppm add: 9.0 ml of 37% reagent grade HCl (specific gravity 1.18) per 100 litres of bath. b) The anodes must be etched in a standard persulfate microetch, such as Dow PREPOSIT Etch 748. The etch should remove all foreign material and leave a uniform matte pink surface. The anodes should be thoroughly rinsed with water after etching. c) Install the anodes in anode bags previously soaked in hot deionized water followed by an overnight soak in 10% by volume reagent grade sulfuric acid. d) Adjust to operating temperature and add 1.25% by volume of ELECTROPOSIT 1100 C-2 Acid Copper Additive. Note: ELECTROPOSIT 1100 C-2 Acid Copper Additive should be added to the tank just prior to starting up the bath. e) Current density should be ramped up to operating level to activate the additive system components. Using dummy panels from scrap laminate at an anode to cathode ratio of 1:1, dummy plate the bath for the following current densities and times. Current Density Time 0.5 A/dm 2 1 hour 1.0 A/dm 2 1 hour 1.5 A/dm 2 1 hour 2.0 A/dm 2 1 hour Then add 0.4 ml/l of ELECTROPOSIT 1100 B-2 Acid Copper Additive and plate a new dummy panel at 2.0 A/dm 2 for 1 hour. If the deposit on the panel is bright, begin plating production work. If not, analyze the bath components (see Bath Control section, below). Depending on the results, continue to dummy or make an addition of ELECTROPOSIT 1100 B-2 Acid Copper Additive. Bath Conversion Do not use plating solution that contains other additives. The bath should be discarded and a fresh solution made-up. Page 3 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

4 Bath Control To ensure that the main constituents of the bath are within the recommended ranges, analysis and control of the following is necessary: Copper sulfate Sulfuric acid Chloride ion Additive level Hull Cell Testing, metallographic cross-sectioning and thermal shock testing should be optimum operating conditions. Hull Cell Test Temperature: 22 C Current: 2.0 amp Anode: Phosphorized copper (0.03% 0.08%P) Cathode: 7.62 cm x cm polished copper or brass panel Plating Time: 10 minutes Agitation: Air agitation is necessary I. Pretreatment of Hull Cell Panel Plastic gloves and forceps should be used to handle the copper or brass panel. a) Remove protective film from copper or brass panel and pumice scrub. b) Immerse panel in 50% b.v. of Neutra-Clean 68 cleaner or equivalent for 90 seconds at 71 C with agitation. c) Thoroughly rinse with hot water. d) Rinse with deionized water. e) Immerse in 10% H 2SO 4 for about 30 seconds. Note: Copper or brass panel should be free of water breaks at this point. f) Transfer to Hull Cell and test. Interpretation of Results Note: Concentration of bath constituents should be within recommended ranges before utilizing Hull Cell Test. Page 4 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

5 Metallographic Cross-Section Prepare the cross-section in the normal way; after polishing, the sample should be microetched so that the copper grain structure can be examined. I. Interpretation of Results A bath operating at optimum conditions will exhibit a fine-grained deposit. An increase in the concentration of organic or metallic impurities will result in a columnar structure, perpendicular to the substrate surface. Thermal Shock (Solder Float) Test Bath Treatment to Remove Organic Contamination The deposit may be subjected to IPC Standard Specification ANSI/IPC-SD-320B (latest issue), U.S. Military Specification MIL-P-55110D Par , and MIL-C-14550B. I. Interpretation of Results Microscopic examination of the metallographic cross-section of through holes after thermal shock test should reveal no cracks. In addition, the boards should exhibit no measling, fractures or separation of plating and conductors, blistering or delamination. If previous tests indicate that contamination is present in the bath, check by analysis that the problems are not caused by incorrect concentrations of copper sulfate, sulfuric acid, chloride ion or additive. If within range, proceed as follows: I. Carbon Treatment to Remove Organic Contamination a) Transfer the plating solution to a holding tank. b) Add 12 g/l powdered activated carbon (Norit RO 0.8 carbon or Norit SX4 or equivalent) and stir the bath for 4 6 hours at room temperature. c) Remove a sample, filter and check by Hull Cell Testing that treatment is complete. If the Hull Cell panel deposit is matte down to 0.5 A/dm 2, this shows that a sufficient amount of organic contaminants have been removed, an indication that treatment is complete. d) Allow the carbon to settle to the bottom of the tank. Transfer the solution to the plating tank by filtration using a 5-micron filter. Coat the filter with diatomaceous earth prior to transfer to ensure that no carbon fines are passed over to the plating tank. e) Adjust to operating temperature and add 1.25% by volume of ELECTROPOSIT 1100 C-2 Acid Copper Additive. Ramp up the current density (according to New Bath Installation, Section IIIe above), then add 0.4 ml/l of ELECTROPOSIT 1100 B-2 Acid Copper Additive. The bath is now ready for use. Put in a fresh dummy and plate at 2 A/dm 2 for 1 hour. If the panel is bright, continue with production. If the panel is not bright, adjust to optimum conditions according to the Bath Analyzer. Page 5 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

6 Bath Analysis and Control s Chloride Control (Preferred Method) Chloride Control (Alternate Method) I. Principle This is a titration to precipitate chloride by reaction with silver nitrate. The reaction will cause a change in potential on a chloride ion specific electrode. This method is more costly but yields a more accurate result for a low chloride bath. I Equipment a) Metering pump or syringe pump (0.5 ml per minute) b) 50 cc Plastic syringe c) Chart recorder (0 to 50 mv) d) Chloride ion specific electrode e) Saturated Calomel reference electrode Reagents a) Silver nitrate; dissolve 2.5 grams into 1 liter of deionized water b) Sodium chloride standard solution; dissolve exactly 9.88 grams in 1 liter of D.I. water IV. a) Pipette 1 ml of the sodium chloride standard into 100 ml of D.I. water. b) Start flow of silver nitrate solution into beaker using a syringe pump at 0.5 ml per minute. c) Record this potentiometric titration on the chart recorder at 50 mv full scale and a chart speed of 125 cm per hour (0.25 cm per minute). d) Replace the solution with a 100 ml sample of the plating bath and repeat the titration in the same manner. e) Record the number of lines to reach the inflection point of the titration. V. Calculation The standard represents 50 ppm of chloride. The bath sample is to be compared to this standard to determine the chloride level in the plating bath as follows: ppm of chloride = # of lines to inflection point of bath sample x 50 # of lines to inflection point of standard I. Principle This is a titration to complex suspended silver chloride with mercuric ion. I Reagents a) 1:1 concentrated nitric acid with deionized water b) Silver nitrate solution, 0.1N c) Mercuric nitrate solution (Hg(NO 3) 2), 0.01N a) Pipette a 50 ml sample of ELECTROPOSIT 1100 B-2 bath into a 250-ml beaker. b) Add 30 ml of distilled water and 20 ml of 1:1 nitric acid. c) Add 3 to 5 drops of 0.1N silver nitrate with stirring. d) Immediately titrate with 0.01N mercuric nitrate solution until the turbidity disappears. Page 6 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

7 IV. Calculation ppm of chloride = ml of Hg(NO 3) 2 x N of Hg(NO 3) 2 x 35,453 sample size (50 ml) Sulfuric Acid Control I. Principle This is an acid-base titration using bromophenol blue as the indicator. I IV. Reagents a) Sodium hydroxide (NaOH), 1.0N, standardized b) Bromophenol blue indicator, 0.1% aqueous solution a) Pipette a 10 ml sample of bath into a 100-ml volumetric flask, dilute to mark with distilled water and mix. b) Pipette 10 ml of the dilute solution into a 250 ml Erlenmeyer flask and dilute to 150 ml. c) Add 5 to 10 drops of indicator and titrate with sodium hydroxide, 1.0N, until the color changes from a yellow to a violet end point. d) Record the number of ml of NaOH titrated. Calculation g/l H 2SO 4 = ml of NaOH x N of NaOH x 49.1 aliquot (1.0 ml) (g/l) x (0.054) = % by volume Copper Control I. Principle This is an iodometric titration to determine the copper sulfate pentahydrate concentration in an acid medium. I Reagents a) Solid potassium iodide b) 50% by volume sulfuric acid c) Starch indicator d) Sodium thiosulfate (Na 2S 2O 3), 0.1N a) Pipette a 10 ml sample of plating bath into a 500 ml Erlenmeyer flask. b) Add 100 ml of D.I. water. c) Add 20 ml of 50% sulfuric acid. d) Add 6 grams of potassium iodide solid and mix. e) Begin titration with sodium thiosulfate titrant until the solution just begins to lighten from dark brown to light brown. f) Add 4 ml starch indicator and quickly titrate to the end point. The solution will change from a dark brown/purple color to a light pink color at the end point. g) Record the number of ml of Na 2S 2O 3 titrated. Page 7 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

8 IV. Calculation To determine the concentration of copper sulfate pentahydrate in units of grams per liter: g/l CuSO4 5H 2O = ml of Na 2S 2O 3 x N of Na 2S 2O 3 x sample size (10 ml) (g/l) x (0.133) = oz./gal. Deposit Data Typical Values Elongation: Ultimate tensile strength: Microscopic structure: Solderability: Purity: 20% on mm (50 micron) thick foil 46,000 50,000 psi Fine-grained, equiaxed Excellent pure copper Product Data ELECTROPOSIT XP Starter Solution, ELECTROPOSIT 1100 B-2 Acid Copper Additive and ELECTROPOSIT 1100 C-2 Acid Copper Additive are nonflammable, aqueous solutions with the following typical properties: ELECTROPOSIT 1100 B-2 Acid Copper Additive Appearance: Clear ph: ~6.0 Specific 20 C: ~1.00 ELECTROPOSIT 1100 C-2 Acid Copper Additive Appearance: Clear to milky white ph: ~9.0 Specific 20 C: ~1.00 Page 8 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009

9 Handling Precautions Before using this product, consult the Material Safety Data Sheet (MSDS)/Safety Data Sheet (SDS) for details on product hazards, recommended handling precautions and product storage. CAUTION! Keep combustible and/or flammable products and their vapors away from heat, sparks, flames and other sources of ignition including static discharge. Processing or operating at temperatures near or above product flashpoint may pose a fire hazard. Use appropriate grounding and bonding techniques to manage static discharge hazards. CAUTION! Failure to maintain proper volume level when using immersion heaters can expose tank and solution to excessive heat resulting in a possible combustion hazard, particularly when plastic tanks are used. Storage Disposal Considerations Store products in tightly closed original containers at temperatures recommended on the product label. Dispose in accordance with all local, state (provincial) and federal regulations. Empty containers may contain hazardous residues. This material and its container must be disposed in a safe and legal manner. It is the user's responsibility to verify that treatment and disposal procedures comply with local, state (provincial) and federal regulations. Contact your Dow Electronic Materials Technical Representative for more information. Contact: North America: Japan: (+81) Asia: (+852) Europe: (+41) For Industrial Use Only. This information is based on our experience and is, to the best of our knowledge, true and accurate. However, since conditions for use and handling of products are beyond our control, we make no guarantee or warranty, expressed or implied, regarding the information, the use, handling, storage or possession of the products, or the applications of any process described herein or the results sought to be obtained. Nothing herein shall be construed as a recommendation to use any product in violation of any patent rights. Page 9 of 9 ELECTROPOSIT 1100 B-2 Acid Copper Additive/Interconnect Technologies September 2009