Metal Finishing Guide Book

2013

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ZCT 0.34 sec 1.91 mN 0.36 sec 1.49 mN Pressure cooker 8 h 0.81 sec 0.71 mN As plated 0.33 sec 2.07 mN Pressure cooker 4 h 0.35 sec 1.54 mN Pressure cooker 8 h Betatec As plated Pressure cooker 4 h Reference Fmax 0.80 sec 0.56 mN Table 3: Results Demonstrating no Loss to Solderability After Post-Dip Treatment Steam-aging: The "pressure cooker test" is used to promote corrosion, diffusion, and deposit cracking. This test was conducted for a duration of 8 hours, after which contact resistance measurements were carried out. The pressure cooker test parameters included: ➢ high temperature 105 °C ➢ high humidity 100% RH ➢ high pressure 1.192 atm Results inferred no increase in contact resistance after 8 hours of exposure. Figure 7 depicts little change in contact resistance values for Betatec 1 and 2 test samples, before and after the pressure cooker test, using the very low tracking force of 5cN. SOLDERABILITY STUDY This study was carried out to confirm that Betatec post-dip would not effect solderability properties. The gold thickness was reduced to 0.1 μm for these solderability tests. The lead-free alloy SAC (SnAgCu) was used as solder with the following conditions: Solder Temperature Density Immersion time Sensitivity Submergence Velocity SnAgCu 245°C 7.5 mg/mm3 10 s 2.5 3 mm 21 mm/s All tests were conducted in accordance with the IEC-68-2-69 standard using a Litton Kester 950 E3.5 flux. Both zero crossing time (ZCT) and wetting force (Fmax) were used to assess solderability, highlighted in Table 3. 237

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