Deliverable D3.3 Plant Trials and Optimisation Report C-Tech Innovation 29th October 2013 1

Deliverable D3.3 Surface Finishing Printed Circuit Board Manufacture Plastics etching (Polypropylene, ABS, Polyetherimide, Polyimide, Polyphenyleneoxide-Noryl, Carbon fibre composite) Barrel Plating Printed Circuit Board Manufacture Desmear following drilling Copper Etch

Pilot Scale Testing

Plastic Etching Plastics Treated: Polypropylene, ABS, Polyetherimide, Polyimide, Polyphenyleneoxide (Noryl), Carbon fibre composite Analysis of performance: Weight Loss, Gloss meter (GU), Visual inspection microscopy, SEM All samples cleaned and degreased prior to treatment. Water – The only etchant seen to have an effect on polypropylene which is an important polymer for the project partner Promet. Also various academic papers site water as a good etchant for various polymers when combined with US. Acidic Permanganate – Showed potential improvements in etching of ABS and carbon fibre composite when combined with US. Alkali Permanganate – Showed good etching and desmear of polymers used in electronics.

Water Etching – Small samples 25mm x 100mm Little difference in weight, mostly increase. ABS highest. Polypropylene showed weight loss

Water Etching – Small samples 25mm x 100mm Largest gloss reduction on ABS. Increase on polypropylene.

Water Etching – Large Samples 200mm x 100mm Samples placed directly on base of the tank. PPL similar weight loss, but also on CF and Copper

Plastic Etching - ABS Potassium permanganate at 40g/litre with 45%w/v phosphoric acid Bath has limited life time, Mn +7 reduced to Mn +4 Sample number  Temperature Time Ultra- Gloss reduction Weight oC min sound GU change 1 60 5 No -40 -0.038% 2 15 -61 -0.092% 3 Yes -59 -0.150% 4 -67 -0.603% Silent Ultrasound 8

Plastic Etching – Carbon Fibre Sample weight loss higher with US. Gloss reduction higher silent and visual inspection shows more epoxy removed. Sample   US Temp oC Gloss change (GU) Weight Average Side 1 Side 2 Change 1 Yes 52.5 -96.2 -96.9 -1.94% 2 No 58 -97 -97.5 -1.19% Silent Ultrasound

Barrel Plating - Tin Tin plating of washers in barrel. US application reduced plating time by 15%. Savings on electroplating power supply, bath heating and barrel turning.

Barrel Plating - Tin More weight deposited with US Less consistent surface with US.

PCB Desmear Silent Multilayered boards treated with alkali potassium permangenate following solvent swell. Solvent swell using 20% v/v M-treat K, 20 g/l NaOH Rinse- 2 minutes Ultrasound in ½ strength permanganate – 2 minutes 48 seconds 35 and 70 g/L pottasium permanganate 32 g/L NaOH Rinse 3 x 1 minute Nuetraliser 3% v/v H2SO4, 3% v/v 37% H2O2 ( in a 4 L tank, 120 ml of each used) Rinse 2 minutes 12

PCB Desmear Before treatment After treatment Silent Center Edge High Tg Regular Start Mass (g 3.54 1.4 3.35 1.23 End Mass (g) 3.53 1.4034 3.34 1.18 Mass Difference (g) -0.001 0.0034 -0.01 -0.05 13

Copper Etching Acid etch carried out on PCB copper surface layers Pottasium persulphate concentration varied. 14

Copper Etching Larger samples – less defined results. Mass transfer effects an issue due to tank recirculation. 15

Future Work D3.3 final write up D3.4 Construion of plants at Promet and Pragobaord WP4 Assitance with full scale trials WP5 LCA WP6 Roadmapping 16

www.ctechinnovation.com +44 (0)151 347 2900 17