Summary

Summary of Pure Tin Plating Evaluation

Whisker Mitigation Strategy

Select Matte Tin, low stress chemistry
Tight control on bath concentrations
Maintain plating thickness average of 400 – 450 micro inches (10 – 11 microns)
Recommended to apply Post Plate Bake at 150^oC for 1 hour (optional)

Note: No chemical supplier guarantees that the process will be free from whisker.

Lead Contamination Preventive Action
Ref : Customer requirement on maximum lead content is 1000 ppm

Preventive Action

Use high purity solder anodes (99.99% Sn)
Regular bath maintenance to settle down lead
Use dedicated chemical handling apparatus for pure tin process

Wetting Curve of Pure Tin:

Solderability Test Condition:

Solder: Sn-3.8Ag-0.7Cu
Flux: Water Soluble
Temperature: 245 +/- 5 ^oC
Tested material: 14/16L PDIP
Sample size: 11 unit

Result of Solderability Test using Lead-Free solder paste

Solder paste : OMG Microbond NL1D-P3-NCD8001-0
Solder paste type : 96Sn-3.5Ag-0.5Cu
Lead type : 48L TSSOP / 44L PLCC
Type of oven : Vitronics IR Reflow (lab scale)
IR Reflow peak temperature : 260 ^oC
IR Reflow speed : 250 mm/min
Test Result : All parts pass the solderability test as per EIA/JESD22-B102-C and J-STD-002

IR Reflow Profile

Evaluated Package and Lead Type

Whisker Evaluation Result Summary

Summary of Pure Tin Evaluation at Customer M
Test Vehicle: 64L LQFP

click here for solderability evaluation report

Pure Tin Pre-qualification result for Customer I

Pure Tin Pre Qualification for Customer I

Impurities Composition

Conclusion:
AIT's lead-free plating has passed all qualification requirements.