(HASL) Tin/Lead hot air solder level;
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+ Excellent solderability
+ Inexpensive
+ Allows large process windows
+ Tried and tested surface finish
+ Shelf life – min. 12 months
| - Not completely flat soldering surfaces
- Non-RoHS-compatible surface finish
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(HASL) Lead-free hot air solder level;
Recommended as a replacement for leaded HASL. Should also be regarded as an alternative to other lead-free surface finishes due to its relative flatness.
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+ Excellent solderability
+ Tried and tested surface finish
+ Relatively inexpensive
+ Allows large process windows
+ Shelf life – min. 12 months
| - Not completely flat soldering surfaces (but more flat than leaded HASL)
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Immersion Tin;
Sometimes recommended as a replacement for ENIG, primarily for BGA assembly.
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+ Excellent flatness
+ Good solderability
+ Relatively inexpensive
| - Sensitive to handling
- Shelf life – up to 6 months
- Coating depth is important, placing high demands on process control
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ENIG (Electroless Nickel & Immersion Gold);
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+ Good solderability
+ Tried and tested process
+ Excellent flatness
+ Shelf life 12 months
+ Used as combi process
| - Expensive
- Black pad problems – (oxidation of nickel below the gold layer)
- Coating depth is important, placing high demands on process control |
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OSP (Organic Solder Preservatives);
Recommended for mass production and when there isn't too much time between soldering operations
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+ Excellent flatness
+ Inexpensive process
| - Poorer shelf life – 3-6 months
- Acceptable solderability
- Unreliable with more than two soldering processes
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Immersion Silver;
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+ Good solderability
+ Inexpensive process
+ Excellent flatness
| - Requires a special packaging routine
- There should not be a too long interval between soldering operations
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