CIRCUPOSIT Electroless Copper (USING CUPOSIT Z AND Y-1) For PWB Metallization Applications

Transcription

1 Technical Data Sheet CIRCUPOSIT Electroless Copper (USING CUPOSIT Z AND Y-1) For PWB Metallization Applications Regional Product North America Availability Description CIRCUPOSIT Electroless Copper is an integral part of the CIRCUPOSIT PTH Process, Dow Electronic Materials unique, patented process that redefines the standard for through-hole plating. This novel self-accelerating electroless copper eliminates the need for a separate accelerator step, saving space, increasing process speed, improving reliability and quality. CIRCUPOSIT Electroless Copper provides ease of process control, the highest degree of through-hole reliability, low cost and built-in process flexibility. CIRCUPOSIT Electroless Copper has a wide operating window and offers exceptional stability. In addition, the CIRCUPOSIT Electroless Copper bath is based upon EDTA as the chelate. This bath yields deposits that are smooth, bright pink, uniform in color and low stress. At a temperature of 46 C (115 F), CIRCUPOSIT Electroless Copper will deposit approximately 1.25 μm in 25 minutes. Advantages Bath Make-up Formulated to eliminate the need for an accelerator Low-stress deposit offers excellent adhesion even on high-performance substrates Enhanced hole-wall adhesion and coverage Strong copper-to-copper bonds Exceptional bath stability; reduces required bath maintenance Excellent process latitude Suited for both panel or pattern plate operations Use vigorous air agitation when mixing components in the order shown: D.I. water: 81.2% by volume CIRCUPOSIT 3350 M-1: 15.0% by volume CIRCUPOSIT 3350 A-1: 1.0% by volume CUPOSIT Z: 2.3% by volume After mixing well, raise the temperature of the bath to the operating level. CUPOSIT Y-1: 1.15% by volume Mix well and use promptly. Page 1 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

2 Bath Operation Bath Operation Temperature Immersion Time Thickness Bath Loading Agitation Rinsing Ventilation Vibration Filtration Tank Design C ( F), optimum 46 C (115 F) 1.25 microns (50 millionths of an inch) will typically be plated by a cycled bath, operating at 46 C (115 F), in 25 minutes dm 2 /l ( ft 2 /gal.) Air agitation is required at all times, including when the bath is stored; continuous solution and rack agitation is recommended; rack agitation having a frequency of strokes per minute and a stroke length of cm (1 2 inches) is preferred Using at least two counter flowed rinses, with 4 8 minutes of total rinse time following the CIRCUPOSIT copper bath is recommended Good ventilation is recommended An amplitude of >2.5 cm/sec. (>1.0 in./sec.) is required for small hole 0.38 mm (0.015 inches or less) and/or high aspect ratio product (>6:1) Continuous filtration through a 1 10 micron polypropylene cartridge filter or 50 micron bag filter is recommended; for effective filtration, a minimum of 3 bath volume turnovers per hour is required An overflow-type tank with a discrete sump is recommended Bath Control and Replenishment Prior to sampling the solution for analysis, the bath must be adjusted to the proper operating level with D.I. water and thoroughly mixed. To insure consistently superior results, maintain the bath within the operating range and optimum concentration for each parameter. The table below gives acceptable operating ranges as well as the optimum for each parameter. Bath Operation Component Range Recommended Copper g/l 2.0 g/l EDTA g/l 30 g/l Sodium Hydroxide g/l 8.0 g/l Formaldehyde g/l 3.5 g/l SR 5 12 mg/l 8 mg/l Specific Gravity Maintain bath volume with D.I. water. The CIRCUPOSIT Electroless Copper bath is designed to be controlled, during continuous operation, according to copper concentration. Using the supplied analytical procedures, periodically analyze the bath for copper concentration and replenish according to the following schedule. Important! It is essential that vigorous agitation (air or mechanical) be employed when making replenishments (especially with the CIRCUPOSIT 3350 A-1). Additions of the CIRCUPOSIT 3350 A-1 should be made so that the solution to which it is added passes through the filter before entering the main bath. Because the components of the CIRCUPOSIT Electroless Copper are very concentrated, it is very important to maintain a consistent bail-out schedule to prevent contaminant and by-product build up. To ensure optimum bath performance, additions of water, a consistent bail-out system or both will be required to maintain the specific gravity below the upper limit of By maintaining the proper A-1 to R-1 ratio (A-1/R-1 = ) and the proper bail-out schedule the EDTA concentration will be held within the optimum range. Page 2 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

3 Bath Control and Replenishment (Continued) It is NOT recommended to adjust the EDTA concentration by deviating from the normal replenishment ratio of A-1 and R-1. The CIRCUPOSIT Electroless Copper will not perform properly at very high or very low A-1 to R-1 ratios. Under no conditions should the R-1 pump be turned off in an attempt to lower the EDTA. If the EDTA concentration climbs, the bailout volume should be increased to compensate. If the EDTA concentration falls, additions of CIRCUPOSIT 3350 M-1 should be made to bring the concentration back into range. During idle times, or after lengthy shutdowns, the formaldehyde and sodium hydroxide concentrations will need to be independently adjusted. Bath Strength Replenishment Schedule for 100 liter Bath % Copper Concentrate g/l Copper Concentrate Bail-out CIRCUPOSIT 3350 A-1 CIRCUPOSIT 3350 R-1 CUPOSIT Z If automatic replenishment is used, set pumps to the following ratios CUPOSIT Y-1 Bath Strength Replenishment Schedule for 100 gallon Bath % Copper Concentrate g/l Copper Concentrate Bail-out CIRCUPOSIT 3350 A-1 CIRCUPOSIT 3350 R-1 CUPOSIT Z If automatic replenishment is used, set pumps to the following ratios CUPOSIT Y-1 To determine the volume for manual additions, use the information in the following table. Bath Operation Metric To Raise the By Add Of Copper 0.1 g/l 0.5 ml/l CIRCUPOSIT 3350 A-1 EDTA 1.0 g/l 5.0 ml/l CIRCUPOSIT 3350 M-1 Sodium Hydroxide 1.0 g/l 2.9 ml/l CUPOSIT Z Formaldehyde 1.0 g/l 3.0 ml/l CUPOSIT Y-1 SR 1.0 mg/l 0.33 ml/l CUPOSIT SR Page 3 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

4 Bath Control and Replenishment (Continued) Bath Operation U.S. To Raise the By Add Of Copper 0.1 g/l 1.9 ml/gal. CIRCUPOSIT 3350 A-1 EDTA 1.0 g/l 19 ml/gal. CIRCUPOSIT 3350 M-1 Sodium Hydroxide 1.0 g/l 11 ml/gal. CUPOSIT Z Formaldehyde 1.0 g/l 11.2 ml/gal. CUPOSIT Y-1 SR 1.0 mg/l 1.25 ml/gal. CUPOSIT SR In the case of manual additions, certain extra guidelines should be used before making copper additions. If a solution loss or dilution occurs, additions of 3350 A-1 and 3350 M-1 are used to replenish the bath. A solution loss is determined by reviewing the change in concentration of the copper and EDTA. If both materials are low, a solution loss has occurred. In that case, add the 3350 M-1 component first, then make the required addition of 3350 A-1. DO NOT ADD 3350 R-1. During operation, low copper concentrations are normally indicative of a problem with the automatic replenishment system. The 3350 A-1 and R-1 pumps should be checked for proper operation, as well as the calibration on the copper channel. If a problem is found and the bath is in use at the time, minor adjustments (<20%) can be made to the automatic controller to bring the copper back to optimum. If larger adjustments are required, production loading should be stopped, the copper should be adjusted with 3350 A-1, the EDTA with 3350 M-1, and a dummy load should be run prior to restarting production. If the copper loss occurs when production is not being run, AND the EDTA concentration has not fallen, additions of 3350 A-1 should be made to adjust the copper concentration, DO NOT ADD 3350 R-1. Equipment Tanks: Polypropylene, polyethylene or PVC Racks: 304 or 316 stainless steel, or PTFE-coated (316 stainless steel is preferred) Heaters: PTFE or PTFE-coated Filter Media: Polypropylene cartridge (1 10 microns) or a 50 micron felt bag Air Lines: Rigid CPVC Yield The typical yield is 8 square meters of laminate per liter (650 surface square feet/gallon) of CIRCUPOSIT 3350 A-1, when operated properly and plated to a thickness of 1.25 microns (50 millionths of an inch). The yield of the other bath components will vary according to their replenishment ratios. Page 4 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

5 Copper Control Using A Spectrophotometer (730 nm) I. Principle Copper is determined spectrophotometrically by measurement of the absorbance at 730 nm. II. III. Reagents and Equipment a) Buffer Solution; add 100 grams of sodium acetate, anhydrous (or 166 grams of sodium acetate trihydrate) to 600 ml of distilled water, stir to dissolve; add 25 ml of acetic acid, mix well, and dilute to one liter b) Spectrophotometer capable of 730 nm a) Prepare a fresh CIRCUPOSIT Electroless Copper as follows: Make-up: Use a 1 liter volumetric flask D.I. water: 500 ml CIRCUPOSIT 3350 M-1: 150 ml CIRCUPOSIT 3350 A-1: 10 ml CUPOSIT Z: 23 ml Bring volume up to 1 liter with D.I. water. b) Prepare a standard (STD A) by accurately measuring 200 ml of the above solution and diluting it with 400 ml (accurately measured) of buffer solution. Note: This standard should be saved and stored in a glass bottle. The CIRCUPOSIT copper standard has a one month shelf life. c) Ensure the spectrophotometer is warmed up for at least 15 minutes and wavelength is set to 730 nm. d) Insert blank solution (buffer solution) in the sample well and zero spectrophotometer. Remove blank after the spectrophotometer is zeroed. e) Fill a cuvette with the 100% copper standard solution and insert into sample well and record the absorbance reading as STD A. Note: Depending on the spectrophotometer, the absorbance reading from the copper standard is normally good for one week. Each week the absorbance on the copper standard should be checked and the calculation adjusted if necessary. f) Accurately pipette 10.0 ml of sodium acetate buffer into a clean beaker. Accurately pipette 5.0 ml of copper bath into same beaker. Mix well and fill cuvette. g) Insert cuvette of bath sample into the sample well. Record the absorbance reading as BATH. IV. Calculation Abs of Bath Abs of STD A or Abs of Bath Abs of STD A x 100 = Percent copper x 2.0 = g/l copper Page 5 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

6 Sodium Hydroxide and Formaldehyde Control EDTA Control I. Principle The sodium hydroxide is determined potentiometrically by an acid-base titration to ph The formaldehyde is determined by the titration of the sodium hydroxide formed during the addition reaction between formaldehyde and sodium sulfite. II. III. IV. Reagents a) 0.10N Hydrochloric acid, standardized b) Sodium sulfite, crystals a) Pipette a 5 ml sample of the bath into a 250 ml beaker. b) Add approximately 100 ml of distilled water. c) Using a ph meter buffered at 10.0, titrate to a ph of 10.2 with 0.10N HCl. Record ml titrated for the caustic calculation. d) Adjust the ph to 10.0 with the 0.10N HCI. Refill burette with 0.10N HCI. e) Add 1 2 grams of sodium sulfite crystals and mix to dissolve. f) Titrate to a ph of 10.0 with 0.10N HCl. Record the ml of HCl used in this step for the formaldehyde calculation. Calculations ml HCl N of HCl 8 = g/l sodium hydroxide (NaOH) ml HCl N 6 = g/l formaldehyde I. Principle Total EDTA is determined as the sum of complexed and free EDTA. Complexed EDTA is determined from the copper concentration. Free EDTA is determined by titrating the CIRCUPOSIT copper bath with a standardized copper solution. II. III. Reagents a) Ammonium chloride (ph 10) buffer: dissolve 70 grams of ammonium chloride in approximately 400 ml distilled water; add ammonium hydroxide to a ph of 10.0; dilute to 1 liter with distilled water b) 0.016M Cu ++ Standard: dissolve grams of CuSO 4 5H 2O in distilled water and dilute to 1 liter; standardize with primary EDTA titrant c) 0.1% PAN indicator: dissolve 0.1 gram of 1-(2-pyridylazo)-2-naphthol in ethanol and dilute to 100 ml a) Pipette a 10.0 ml sample of CIRCUPOSIT Electroless Copper bath into a 250 Erlenmeyer flask. b) Add approximately 75 ml of distilled water. c) Add 20 ml of ammonium chloride ph 10.0 buffer and drops of 0.1% PAN indicator. d) Titrate with 0.016M Cu ++ Standard to violet endpoint. Page 6 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

7 EDTA Control (Continued) IV. Calculation Free EDTA ml Cu ++ Molarity (0.016) 416 = g/l Free EDTA sample size (10 ml) Complexed EDTA 6.55 g/l copper = g/l Complexed EDTA Total EDTA Complexed EDTA + Free EDTA = g/l Total EDTA SR Control I. Principle A sample of both the working CIRCUPOSIT electroless copper bath and the CIRCUPOSIT bath standard are separated using methylene chloride to extract the SR. The absorbance of both samples is measured spectrophotometricly and the results compared. II. III. Reagents/Equipment a) Concentrated methylene chloride b) Spectrophotometer capable of a wavelength setting of 282 nm c) 125 or 250 ml separatory funnel and ring stand d) Quartz cuvettes Note: DO NOT use plastic or glass cuvettes a) Prepare a fresh CIRCUPOSIT Electroless Copper bath standard as follows: Make-up: Use a 1 liter volumetric flask D.I. water: 500 ml CIRCUPOSIT 3350 M-1: 150 ml CIRCUPOSIT 3350 A-1: 10 ml CUPOSIT Z: 23 ml Bring volume up to 1 liter with D.I. water. Note: Store bath standard in a glass container. DO NOT store in plastic. The bath standard has a maximum shelf life of one month. b) Analyze both the working copper bath and the copper bath standard and compare results. c) Ensure the spectrophotometer is warmed up for at least 15 minutes and the wavelength set for 282 nm. d) Pipette a 20 ml sample of the copper bath or standard into a 125 or 250 ml separatory funnel. e) Add 20 ml of concentrated methylene chloride. f) With the cap on, shake the solution for at least one minute. Vent the built-up gas through the stop cock every few seconds for the first 30 seconds. g) Place separatory funnel on a ring stand and allow the 2 layers to separate. Page 7 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

8 SR Control (Continued) IV. h) The methylene chloride is the bottom layer. i) Remove the cap and drain about 5 ml of the methylene chloride into a waste container. This is to clean out any residue that may have been blown into the neck of the separatory funnel during venting. j) Rinse a clean quartz cuvette several times with the separated methylene chloride. k) Fill the quartz cuvette with a sample of the separated methylene chloride. l) Prior to reading the bath sample, the spectrophotometer must be zeroed with a fresh solution of methylene chloride. m) Once the spectrophotometer has been zeroed with the blank methylene chloride, place the cuvette containing the separated methylene chloride into the spectrophotometer and read the absorbance. n) Compare the absorbance of the working bath with the absorbance of the copper bath standard. Calculation Abs. of Working Bath 5.7 = SR content in mg/l Abs. of copper Std. Product Data CIRCUPOSIT 3350 A-1 Specific Gravity at 20 C: ~1.35 Wt./gal.: 11.2 lb. Appearance: Green ph: <2.0 CIRCUPOSIT 3350 R-1 Specific Gravity at 20 C: ~1.20 Wt./gal.: 10.0 lb. Appearance: Water-white to pale yellow ph: ~10.0 CIRCUPOSIT 3350 M-1 Specific Gravity at 20 C: ~1.20 Wt./gal.: 10.0 lb. Appearance: Water-white to pale yellow ph: ~10.0 Bath Storage The bath should be stored at % copper at F (15 26 C). Air agitation is required during storage. To start-up the CIRCUPOSIT Electroless Copper bath, copper, EDTA, sodium hydroxide and formaldehyde should be brought to optimum operating levels. Page 8 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014

9 Handling Precautions Before using this product, associated generic chemicals or the analytical reagents required for its control, consult the supplier's Material Safety Data Sheet (MSDS)/Safety Data Sheet (SDS) for details on material 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. Product Stewardship Customer Notice Dow has a fundamental concern for all who make, distribute, and use its products, and for the environment in which we live. This concern is the basis for our product stewardship philosophy by which we assess the safety, health, and environmental information on our products and then take appropriate steps to protect employee and public health and our environment. The success of our product stewardship program rests with each and every individual involved with Dow products - from the initial concept and research, to manufacture, use, sale, disposal, and recycle of each product. Dow strongly encourages its customers to review both their manufacturing processes and their applications of Dow products from the standpoint of human health and environmental quality to ensure that Dow products are not used in ways for which they are not intended or tested. Dow personnel are available to answer your questions and to provide reasonable technical support. Dow product literature, including safety data sheets, should be consulted prior to use of Dow products. Current safety data sheets are available from Dow. 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. Contact: North America: Taiwan: China: (+86) Hong Kong: (+852) Korea: (+82) Japan: (+81) Europe: (+41)(0) NOTICE: No freedom from infringement of any patent owned by Dow or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer's use and for ensuring that Customer's workplace and disposal practices are in compliance with applicable laws and other government enactments. The product shown in this literature may not be available for sale and/or available in all geographies where Dow is represented. The claims made may not have been approved for use in all countries. Dow assumes no obligation or liability for the information in this document. References to Dow or the Company mean the Dow legal entity selling the products to Customer unless otherwise expressly noted. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED. Page 9 of 9 CIRCUPOSIT Electroless Copper / Interconnect Technologies August 2014