Soldering Method for Fine Pitch QFP's

What is the proven industry solder attachment process for installing 240 lead (gull wing) quad flat packages with lead pitch < 0.025 when used in a high reliability space applications? Hand Solder? Vapor Phase? IR Reflow? Hot Air/Gas? Hot Bar?

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| What is the proven industry solder attachment process for installing 240 lead (gull wing) quad flat packages with lead pitch < 0.025 when used in a high reliability space applications? | Hand Solder? | Vapor Phase? | IR Reflow? | Hot Air/Gas? | Hot Bar? Hi there. Properly dialed in, any of the above processes will work in your application. It's a question of economics. I personally prefer forced air convection / IR technology coupled with automatic placement, but that's because I have good processes and controls for this technology. for example, I'm NOT arrogant enough to say that hand soldering is impossible for this activity, but if you go that route, plan on lots of TIME and a HIGHLY certified / qualified person and iron to do the work. I'd use a solid printing process with a solid placement process and a solid reflow process. Bam! you're done. Scott Cook scottc@t-com.com

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| What is the proven industry solder attachment process for installing 240 lead (gull wing) quad flat packages with lead pitch < 0.025 when used in a high reliability space applications? | Hand Solder? | Vapor Phase? | IR Reflow? | Hot Air/Gas? | Hot Bar?

The leads on the 240 pin QFP has shorter feet thus making the attachment trickier. Coplanarity may be a problem. Also, because the package is physically larger than other QFPs, board warpage can be a problem. We are having a harder time with 240 QFPs and will be looking to use more BGAs for similar applications in the future.

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