Technical Data [email protected] www.technic.com

405602 – NEW 0410

TechniSol® Cu 2440 TechniSol® Cu 2440 is a unique copper electrodeposition process designed for high-build metallization of photovoltaic cells. It is a low stress Cu plating system developed to provide high current carrying capacity while reducing stress and wafer bow. It produces a bright, low stress deposit at 40 to 60 ASF (4-6 ASD). The electrodeposits produced by the TechniSol® Cu 2440 process are fine grained equiaxed, high purity, ductile copper deposits that will meet or exceed all advanced technology requirements of the photovoltaic industry. The specific combination of TechniSol® Cu 2440 Brightener, Carrier, and Stress Reducer provides a wide process window to maintain low stress and excellent ductility. All of the components in the process are fully analyzable and the TechniSol® Cu 2440 process is specifically optimized for control by the Technic EBA (Electroplating Bath Analyzer).

FEATURES AND BENEFITS 1. Low stress deposit preventing solar cell bow. 2. Plates at high current densities. 3. Stable additives yielding predictable low additive consumption. 4. High purity fine grained, equiaxed deposits. 5. Operates with air or solution agitation. 6. Compatible with high-speed horizontal, vertical plating, or Semcon plating equipment. 7. Easily controlled by Electroplating Bath Analyzer, and/or auto-dosing.

TechniSol® Cu 2440

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DEPOSIT CHARACTERISTICS Structure: Density: Conductivity: Electrical Resistivity: Elongation: Tensile Strength: Yield Strength: Modulus of Elasticity: Hardness: Internal Stress

Fine grained, equiaxed 8.9 g/cm3 0.59 mega Siemens/cm 1.7 – 1.8 microhm/cm 18 – 33% 280 – 350 N/mm2 (40 – 50 KPSI) 175 – 245 N/mm2 (25 – 35 KPSI) 3.8 – 5.4 MPSI 180 – 220 Knoop, as deposited, 80 – 120 Knoop after 2 – 4 days at room temperature or 1 – 2 hours at 100°C (212°F) 0-1500 PSI Compressive as Plated (Measured by Spiral Contractometer)

TOOL/MATERIALS OF CONSTRUCTION Tank Materials:

Temperature-stabilized translucent white polypropylene, polyethylene, rigid PVC, Koroseal lined steel with Plastisol-coated exterior or other materials that will not contaminate the system.

Heaters:

PTFE coated or PVDF-clad panel heaters with thermostatic control

Anodes:

Phosphorous-deoxidized copper (0.04 – 0.08% P) bar anodes or copper chunks/mini-slugs in suitably sized titanium baskets.

Anode Bags:

Un-napped Terylene®, polypropylene or Dynel®.

Filtration:

Continuous using leached 1–5 micron woven polypropylene cartridges with a flow rate of three (3) – five (5) times the tank volume/hour.

Agitation:

Polyvinyl dichloride (PVDC) distribution sparger with 11/2 CFM per square foot tank surface using low pressure oil free air plus mechanical reciprocation, normal to the anodes, to produce flowing action of the solution through the holes.

Power Supply:

4 – 6 volt rectifier with a maximum 5% ripple is recommended. For optimal plating distribution, split rectification is preferred.

TOOL PREPARATION Tanks: Prior to makeup, the process tank and ancillary equipment should be thoroughly cleaned and then leached with a sulfuric acid solution. This procedure is particularly important for new tools or tools previously used for other processes.

TechniSol® Cu 2440

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Cleaning Solution Trisodium Phosphate (TSP) and/or Sodium Hydroxide

22.5 – 45 g/l

3 – 6 oz/gal

22.5 – 45 g/l

3 – 6 oz/gal

100 ml/l

10% v/v

Leaching Solution Sulfuric Acid (H2SO4) Leaching Procedure 1. Thoroughly wash down the tank and ancillary equipment with clean water. Recirculate the water through the complete system to remove water soluble materials. 2. Discard the water. 3. Add the Cleaning Solution to the tank, heat to 38 – 50°C (100 – 120°F) and recirculate through the complete system for 4 – 8 hours. 4. Discard the Cleaning Solution. 5. Recirculate the water through the complete system. 6. Discard the water. 7. Add the Leaching Solution and recirculate through the complete system. Leave the Leaching Solution in the tank for a minimum of eight (8) hours. 8. Recirculate the leaching solution through the complete system. 9. Discard the Leaching Solution. 10. Recirculate the water through the complete system. 11. Discard the water. Anodes: 1. Immerse the anodes in a standard micro etch solution. 2. Rinse thoroughly. 3. Immerse the anodes in 10% v/v (100 ml/l) Sulfuric Acid (H2SO4) solution. 4. Rinse thoroughly with deionized water. 5. When Titanium anode baskets are used, care must be taken to ensure that they are completely filled with copper anode slugs.

TechniSol® Cu 2440

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Anode Bags & Polypropylene filter cartridges: 1. Wash thoroughly in hot (140°F, 60°C) deionized water. 2. Leach with 10% v/v (100 ml/l) Sulfuric Acid (H2SO4) solution for eight (8) hours. 3. Rinse thoroughly with deionized water.

SOLUTION MAKEUP Chemicals Required

1 liter

1 gallon

980 ml

98% v/v

TechniSol® Cu 2440 Brightener

5 ml

0.5% v/v

TechniSol® Cu 2440 Carrier

5 ml

0.5% v/v

TechniSol® Cu 2440 Stress Reducer

7 ml

0.7% v/v

Elevate Cu Electrolyte 40

MAKEUP PROCEDURE/ORDER OF ADDITION 1. Fill an adequately cleaned electroplating tank with 98% of Elevate Cu Electrolyte 40. 2. Insert bagged anodes into the plating tank. 3. Add 0.5% v/v (5 ml/l) of TechniSol® Cu 2440 Carrier and mix thoroughly. If using new anode bags, an additional 0.1 to 0.2% v/v (1 – 2 ml/l) may be required due to absorption by the anode bags. 4. Electrolysis – (Required before running production). Conditioning of TechniSol® Cu 2440 solution is required to film the anodes and produce optimum conditions of operation. 5. Electrolyze using clean metalized cathodes at 2.0 A/dm2 (20 A/ft2) for 1 hour. Make TechniSol® Cu 2440 Carrier additions as necessary during electrolysis. Check the chloride concentration and adjust to 90 ppm, if necessary. 6. Add 0.5% v/v (5 ml/l) of TechniSol® Cu 2440 Brightener and mix thoroughly. If using new anode bags, an additional 0.1 to 0.2% v/v (1 – 2 ml/l) may be required due to absorption by the anode bags. 7. Add 0.7% v/v (7.0 ml/l) of TechniSol® Cu 2440 Stress Reducer and mix thoroughly.

8. Electrolyze solution at 2 A/dm2 (20 A/ft2) for 1 hour. Re-check TechniSol® Cu 2440 Brightener, TechniSol® Cu 2440 Carrier, TechniSol® Cu 2440 Stress Reducer levels and adjust, if necessary.

TechniSol® Cu 2440

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STANDARD OPERATING PARAMETERS: Range:

Optimum:

Copper Sulfate Pentahydrate(CuSO4 · 5H20)

140 – 170 g/l

150 g/l

Copper Metal

35 – 42.5 g/l

37.5 g/l

7 – 13% v/v 70 – 100 ppm (70 – 100 mg/l)

10% v/v 90 ppm (90 mg/l)

TechniSol® Cu 2440 Brightener

0.4 – 1.0% v/v

0.5% v/v

TechniSol® Cu 2440 Carrier

0.3 – 0.7% v/v

0.5% v/v

TechniSol® Cu 2440 Stress Reducer

0.5 – 1.4% v/v

0.7% v/v

Sulfuric Acid (98% Pure Grade) Chloride Ion

Temperature Cathode Current Density Anode Current Density Anode to Cathode Distance Filtration Rate Deposition Rate

33 – 38°C 35°C (90 – 100°F) (95°F) 40 – 60 A/ft2 (4 – 6 A/dm2) 12 – 40 A/ft2 (1.2 – 4.0 A/dm2) 6 – 12 in. (8 inches optimum) 15 – 30 cm (20 cm optimum) 3 – 5 tank volume turnovers per hour 56 microns/hour at 4 A/dm2 (2.2 mils/hour at 40 A/ft2)

COMPONENT DESCRIPTIONS: TechniSol® Cu 2440 Carrier provides the primary surface active agents which enable the controlled deposition of copper. It is used for make-up and to adjust Carrier concentration based on the Technic EBA or other approved electrochemical analysis TechniSol® Cu 2440 Brightener functions as a grain refiner to allow the uniform, low stress, fine-grained deposition of copper. It is used for make-up and to adjust Brightener concentration based on Technic EBA analysis. TechniSol® Cu 2440 Stress Reducer functions as both a high current density inhibitor and as a secondary grain refiner to allow uniform, low stress, fine-grained copper deposition. It is used for make-up and to adjust the Stress Reducer concentration based on Technic EBA analysis. Elevate Cu Electrolyte 40 is a ready-to-use electrolyte that contains the appropriate amount of copper sulfate, sulfuric acid and chloride. This Electrolyte has a copper metal concentration of 40 g/l.

TechniSol® Cu 2440

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RECOMMENDED REPLENISHMENT AND CONTROL SCHEDULE Component

Analytical Method

Frequency of Analysis

Estimated Replenishment Rate

Volumetric Analysis Atomic Absorption Spectroscopy Volumetric Analysis Specific Ion Electrode Spectrophotometric Volumetric Analysis

Weekly

Based on analysis

Weekly

Based on analysis

Weekly

Based on analysis

EBA Analysis

Daily

EBA Analysis

Daily

EBA Analysis

Daily

Based on analysis

Metallic Contamination (Fe, Ni, Sn)

Atomic Absorption Spectroscopy

Weekly

N/A

Process Performance

Hull Cell

Daily

N/A

Copper Sulfuric Acid Chloride TechniSol® Cu 2440 Brightener TechniSol® Cu 2440 Stress Reducer TechniSol® Cu 2440 Carrier

300 – 400 ml/ 1000 Amp-hrs. 150 – 250 ml/ 1000 Amp-hrs.

See attached Analytical Methods Solution Performance via Hull Cell Testing Plate the panel at 3 amps for 5 minutes and evaluate the copper deposits for brightness and uniformity. The deposit should be bright, with little to no burn in the HCD, across the entire plated area. Purification of the Solution If purification is required, add 1 ml/l of Peroxide (H2O2, 37%), heat to 140°F and hold for 4 hours with constant agitation. Allow to cool to room temperature before proceeding. Carbon polish the solution, by adding either 6 g/l of Technic A-10 granular or 4 g/l of Technic G-60 powder, for 24 hours and readjust the TechniSol® Cu 2440 Brightener and the TechniSol® Cu 2440 Carrier before starting up production. General Maintenance 1. Filters should be changed at 2 – 4 week intervals. 2. Anode area should be checked and maintained on a regular basis. When using a titanium basket/anode slug combination; these should be completely removed and a thorough cleaning of any sludge build-up, replenishment and reconditioning should be performed. 3. Anodes should be bagged with un-napped Terylene®, Dynel® or polypropylene bags. Bags should be checked frequently for any holes, rips or tears. Defective anode bags should be replaced immediately.

TechniSol® Cu 2440

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4. Periodic carbon treatment of the acid copper electrolyte is required. 5. Routine carbon treatments are recommended at 3 – 6 month intervals. 6. Carbon treatment is also recommended if: A. The physical properties of the copper electro-deposit fall below specification. B. The Hull cell panel indicates a presence of either organic contamination or an excess of brightener. Note: Any change in color of the electrolyte from blue (normal color) to a greenish-blue, solid green color indicates the presence of organic build-up. In establishing a carbon treatment schedule and procedure, the use of hydrogen peroxide and/or potassium permanganate to assist in the oxidation of the organics in your electrolyte may be included.

Metallic Impurities The maximum tolerable level of metallic contaminants is listed below: Fe Ni Sn

1000 ppm 1000 ppm 100 ppm

TechniSol® Cu 2440

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TROUBLESHOOTING TIPS

Defect Anode Polarization

Cause Copper Concentration too high.

Correction Analyze the Copper concentration and adjust to optimum.

Sulfuric Acid concentration too high.

Analyze the Sulfuric Acid concentration and adjust to optimum. Analyze the Chloride concentration and adjust to optimum.

Chloride concentration too high. White Anode Film/Polarized Anodes

Chloride concentration too high.

Poor metal distribution

Sulfuric Acid concentration too low.

Dendrites or rough deposits

Chloride concentration too low.

Analyze the Chloride concentration and adjust to optimum

Burning in the high current density range

Concentration of TechniSol® Cu 2440 Brightener is too low.

Add 0.5 – 1 ml/l of TechniSol® Cu 2440 Brightener. Continue adding until the phenomenon disappears. Increase temperature.

Temperature is too low. Poor throw in the low current density range

Concentration of TechniSol® Cu 2440 Carrier is low.

Temperature is too low.

Analyze the Chloride concentration and discontinue additions, if necessary Analyze the Sulfuric Acid concentration and adjust to optimum.

Add 0.5 – 1 ml/l of TechniSol® Cu 2440 Carrier. Continue adding until the phenomenon disappears. Increase temperature.

TechniSol® Cu 2440

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HANDLING PRECAUTIONS All components of the TechniSol® Cu 2440 solution are highly acidic and require the normal precautions for handling of strong acids. Avoid contact with skin and eyes. Handle with care. Wear chemical goggles, chemical gloves and suitable protective clothing when handling any bath component. In case of contact flush affected area with copious amounts of cold, clean water for at least 10 minutes. In case of serious exposure, particularly for eyes, obtain medical attention for acid burn. STORAGE Store all chemicals in their upright, original containers away from direct sunlight and in a dry area at 50 – 90°F (10 – 32°C). Keep containers closed when not in use. Keep away from organics, reducing agents, strong alkalis and oxidizers. WASTE TREATMENT It is the user’s responsibility to verify that treatment procedures comply with federal, state, and local regulations. Working solutions should be diluted, neutralized and disposed of in accordance with local and federal regulations. Consult your local agencies for recommendations for your area. Consult your Technic Inc representative for further information. BEFORE HANDLING ANY CHEMICAL PRODUCTS, IT IS IMPORTANT TO READ THE APPROPRIATE MATERIAL SAFETY DATA SHEET. ORDERING INFORMATION Contact your local Technic company to order products and/or Material Safety Data Sheets: Product Code

Product Name

Liquid

405604

TechniSol® Cu 2440 Stress Reducer

X

405602

TechniSol® Cu 2440 Brightener

X

405603

TechniSol® Cu 2440 Carrier

X

405583

Elevate Cu Electrolyte 40

X

Application For Makeup and Replenishment For Makeup and Replenishment For Makeup and Replenishment of Carrier based on Analysis For Makeup Only 405602 – NEW 0410

The Technical statements, information and data contained herein are believed to be accurate and reliable; however, no warranties, express or implied, including warranties of merchantability or fitness for a particular purpose, are made regarding the products described. Since many variables and factors affect processing, application or use, it is recommended that you perform tests to determine the suitability of this product for your particular use. Any oral statements or advice concerning product selection or use do not constitute warranties. Delivered products are warranted to meet our standard specifications at the time of sale and all sales are subject to the TERMS AND CONDITIONS OF SALE reproduced on the reverse side of each invoice.

TechniSol® Cu 2440

Appendix - Page 1

ANALYTICAL PROCEDURE FOR COPPER METAL Equipment: 2 ml pipette 25 ml graduate cylinder 50 ml burette 500 ml Erlenmeyer flask Reagents: Ammonium Hydroxide, Reagent grade Glacial Acetic Acid, Reagent grade Potassium Iodide Crystals, Reagent grade Starch Indicator Solution 0.1N Sodium Thiosulfate Solution: (Dissolve 24.8 g of Reagent grade Sodium Thiosulfate in DI water and dilute to 1 liter in a volumetric flask. Standardize as required.) Procedure: 1. Pipette 2 ml of the plating bath into a 500 ml Erlenmeyer flask. 2. Add about 20 ml distilled water. 3. Add ammonium hydroxide by drops until a deep blue color develops. 4. Dilute to 150-200 ml with distilled water. 5. Add 10 ml glacial acetic acid and 3-4 grams of potassium iodide. 6. Add 2-3 ml of starch indicator. 7. Titrate with 0.1N Sodium Thiosulfate solution. Calculation: (ml of 0.1N Sodium Thiosulfate) x 1.68 = oz/gal Copper Sulfate (CuSO4.5 H2O) (ml of 0.1N Sodium Thiosulfate) x 12.6 = g/l Copper Sulfate (CuSO4.5 H2O) (ml of 0.1N Sodium Thiosulfate) x 0.42 = oz/gal Copper Metal (ml of 0.1N Sodium Thiosulfate) x 3.15 = g/l Copper Metal

TechniSol® Cu 2440

Appendix - Page 2

ANALYTICAL PROCEDURE FOR SULFURIC ACID Equipment: 5 ml pipette 50 ml burette 250 ml Erlenmeyer flask Reagents: Methyl Orange Indicator Solution:

Dissolve one (1) gram of Methyl Orange in 99 ml of distilled water.

1.0N Sodium Hydroxide Solution (NaOH):

Dissolve 40 grams of AR grade NaOH in water, cool and dilute to 1 liter in a volumetric flask. Standardize against hydrochloric acid or sulfuric acid of known concentration.

Procedure: 1.

Pipette 5 ml of the plating bath into a 250 ml Erlenmeyer flask.

2.

Add 50 ml distilled water and 3-4 drops Methyl Orange Indicator Solution.

3.

Titrate with 1.0N sodium hydroxide until yellow color develops.

Calculation: (ml of 1.0N sodium hydroxide) x 5.66 = ml/l Sulfuric Acid (66oBé) (ml of 1.0N sodium hydroxide) x 0.566 = % v/v Sulfuric Acid (66oBé)

TechniSol® Cu 2440

Appendix - Page 3

DETERMINATION OF CHLORIDE ION CONCENTRATION Equipment: 50 ml pipette 250 ml beaker 50 ml burette Reagents: 1:1 Nitric Acid Solution, Reagent grade 0.1N Silver Nitrate Solution, Reagent grade 0.01N Mercuric Nitrate Solution, Reagent grade Procedure: 1.

Pipette a 50 ml bath sample into a 250 ml beaker.

2.

Add 30 ml of DI water and 20 ml of 1:1 nitric acid.

3.

Add enough 0.1N standard silver nitrate solution to produce turbidity; minimum of 7 drops up to 2 mls are required.

4.

Immediately titrate with 0.01N mercuric nitrate solution by drop wise additions, with constant stirring, until the turbidity just disappears.

Calculation: Chloride ion (PPM) = (ml of 0.01N Mercuric nitrate used) x 7.1

405602 – NEW 0410