Reflow Oven Atmosphere Purity

Folks, I am interested in knowing what level of Nitrogen purity you are running in your reflow ovens for standard SMT assembly? It seems over the last several years people are increasing the Oxygen level in thier reflow oven atmosphere. What purity Level works best for you? Thank you and best regards, Joe Belmonte

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| Folks, | I am interested in knowing what level of Nitrogen purity you are running in your reflow ovens for standard SMT assembly? | It seems over the last several years people are increasing the Oxygen level in thier reflow oven atmosphere. | What purity Level works best for you? | Thank you and best regards, | Joe Belmonte | | It sounds too general, but we require below 1000 ppm for starters. Our target remains below 100 ppm. We do not use nitrogen for everything as it allows some issues to arise as decreased surface tension and faster/easier wetting - or too much of a good thing. This especially is true involving vias in pads for R/F applications. Of course, no one should be practicing this ancient ritual, but this is an example of wetting made too easy while watching the solder go down the drain.

Earl Moon

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| Folks, | I am interested in knowing what level of Nitrogen purity you are running in your reflow ovens for standard SMT assembly? | It seems over the last several years people are increasing the Oxygen level in thier reflow oven atmosphere. | What purity Level works best for you? | Thank you and best regards, | Joe Belmonte | | Joe -

Our ovens are "speced" to reach 20 ppm, but we would probably use so much Nitrogen that another LN2 tank would be needed outside. In the real world, we find that 100 to 200 ppm works fine for our no-clean process.

Glenn Robertson glenn.robertson@usa.alcatel.com

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