Sunday, November 9, 2008

Lead Free HASL

Lead Free HASL

Lead Free HASL


SnCu alloy stabilized with Ni, composed of:
99.3% Tin

Industry Misconceptions

Predictions of HASL’s Demise
Solderability Issues
Short Duration of Usage

Benefits of Pb-HASL

Lower Copper Erosion on PCB surface and vias

Quick Process

Long Shelf Life


a.) Humidity
b.) Handling
c.) Temperature

Solder Joint Strength

Thickness Criteria
•Generic Thickness Requirement
•Not proper to have only one
-Smaller Pads receive thicker solder deposition
• Minimum Alloy Thickness should be segregated by Ranges of Pad Size

•Specific Design Set-Up
–Each Design may require its own specific set-up
•Air Knife Pressure
•Retract Speed
•Dwell Time

•Alloy Control
•Lower copper content of alloy increases solderability
•Standard Drossing of solder pot is not enough to keep copper content below 0.90%
•Recommend a 1/4 - 1/3 solder pot dump once weekly measurement reaches 0.90%

SN100CL Study Conclusion

•No Solderability Issues at any customer
–Fab Notes
•Fab notes can specify the use of these coupons or range of solder thickness standards
–Forcing your supplier to meet these specs will give you:
»Control over the Process

•By implementing these proposed solutions, you can:
–Save up to 30% of your bare board cost
–Increase performance of your products
–Standardize your fab notes to remove risk of non-performing products
–Improve your supply base

For more information on Lead Free Finishes please click here to read more:

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