Solder pastes Analysis  [ Return towards  Our expertise  ]

Under Air                                               Under Nitrogen

Using nitrogen to inert the atmosphere during soldering has by now become a generally accepted practice in electronic assembly. But whereas there seems to be little doubt in the minds of the user that nitrogen "improves" the wave soldering process, and that it actually ‘pays its way’ simply by reducing dross and flux use, its application in reflow equipment is questioned frequently.

These questions about the use of nitrogen in reflow processes are due to the fact that the benefits are often process specific and more difficult to quantify as they are quality based. Quality can be defined here as (1) yield / defects and (2) reliability. In addition to generally improving defect levels and reliability, nitrogen soldering makes cleaning easier and reduces the level of residues left on the board. Lower residues levels make ATE / probe testing easier.

In general, nitrogen will always improve the process but the benefit value analysis will differ. The main parameter of influence in inert reflow soldering is the flux vehicle used. Different flux / paste combinations produce different results under nitrogen. Some flux benefits more from a nitrogen atmosphere than others do.

In an attempt to make process qualification easier, AIR LIQUIDE has developed ALIX™ BASE. ALIX™ BASE is a series of standard tests for solder paste under variable atmosphere. ALIX™ BASE comprises of a wetting test, a coalescence test, and a residue test. An external and certified microelectronics laboratory performs the tests.

• Test 1: Wetting

   

under Air                                                 under Nitrogen


• Test 2: Coalescence

• Test 3: Residues Levels / Flux evaporation

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• Want to view a few examples ?

Please select the following paste / flux type :

Water Soluable

RMA

No-Clean

Low Residues

AIR LIQUIDE can provide specific data on your actual paste. For this service AIR LIQUIDE will need a sample of paste and some basic information about your process and reflow profile. Please contact us for more information.