Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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Soldering Temperature for TQFP160

Igmar

#16855

Soldering Temperature for TQFP160 | 20 January, 1998

Is there anyone who can tell me what is the maximum allowable soldering temperature when soldering a TQFP (Thin Quad Flat Pack) device in a reflow oven? We recently used a CY7C375i in a TQFP160 package and we experienced warping (bending) of this component in the reflow oven, due to excessive heat. We used Sn62Pb36Ag2 solder paste and our peak temperature was 215 degrees Celsius. Is there anyone who experienced this problem before? Should we use a solder with a lower melting point, or is there a problem with the components that we used? I would appreciate any help.

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Scott

#16857

Re: Soldering Temperature for TQFP160 | 21 January, 1998

| Is there anyone who can tell me what is the maximum allowable soldering temperature when soldering a TQFP (Thin Quad Flat Pack) device in a reflow oven? We recently used a CY7C375i in a TQFP160 package and we experienced warping (bending) of this component in the reflow oven, due to excessive heat. We used Sn62Pb36Ag2 solder paste and our peak temperature was 215 degrees Celsius. Is there anyone who experienced this problem before? Should we use a solder with a lower melting point, or is there a problem with the components that we used? I would appreciate any help. Was the warping really a sign of popcorning? Too much moisure absorbed will cause this. I've done various TQFPs but I pay attention to the moisture sensitive data on the packaging and I follow them, the components reach a temp of 210C and I haven't seen the problem.

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Eldon Sanders

#16856

Re: Soldering Temperature for TQFP160 | 22 January, 1998

I'll bet the rate of temperature change may be the problem. A large black thin package will heat quickly, and the package peak temp will be greater than what you measured on the board. The bottom of the package will heat slower than the top, creating a warp. The problem will be worse if you are using an IR oven. Check the profile again and monitor the package temp. Keep the rate of change down in the 2-3 degree C/min area. Allow as much time as you can to make sure the package heats slowly and evenly, without degrading the formation of a good solder joint. Regards,

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