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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Socket T,LGA 775

Bryan Sherh


Socket T,LGA 775 | 31 July, 2004

Dears, Is there any LGA775 socket (Tejas) in your products?or process?Here are some issues that I met in my process,need your help and hope it benefits someone. 1.Because the socket body is really very big and weighs about 37g,need special L size Nozzle to mount the socket. 2.Delta T of full board is very big....and sometimes you can't even stand goal is to heat the socket to 205C of peak temp.and unsure peak temp. of other parts less than 230C.finally I employed one pallet to make it easy for profiling...detailed information please email 3.After reflow,part of the balls of CPU socket terribly deformed,and sometimes contribute to bridging between balls.this is my biggest headache and still haven't settled it down.Under X-ray we found the Balls deformed near the gravity center of Component,and most or all the time short happens in this area....the short failgure rate is about 1%...we changed the profile and decrease the time above 183C,seems no use...I need your help...and your suggestions...or if you also met such issues...please share your experience with us... Thanks a lot Bryan Sherh

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Socket T,LGA 775 | 4 August, 2004

Consider: * Reducing the size of the pads * Reducing the amount of solder paste * Inspecting the print. A print with irregular form (eg, print finishes with a tail, the print is inclined or something like that) * Too long in the reflow zone * Bad alignment in assembly (much pressure, rotation, bad alignment x, y, manual operation, etc)

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Socket T,LGA 775 | 5 August, 2004

The ball pitch is 1.10mm and the pad diameter is 0.45mm,so we designed the aperture diameter as 0.45 on 0.13mm thick stencil.Bridging rate decreased a great deal,but the balls still deformed in the same area.and found it no use reducing the reflow time...Thanks anyway! Regards! Bryan

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