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DQFN INSUFFICIENT SOLDER / HEAD ON PILLOW

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#73650

DQFN INSUFFICIENT SOLDER / HEAD ON PILLOW | 6 March, 2015

Hi,

I have faced some problems with DQFN PACKAGE 132 PIN. After some cross sections and dye pry analysis we could find a head on pillow situation always on inner row pads. The PCBAs are double side and the DQFNs are assembled on Bottom side (Notebook PCBA). The PCB DQFN pads are NSMD.

We have tried at least 5 different stencils designs and many reflow profiles (the current one has the PWI lower than 50%). If we follow the exact supplier stencil opening recomendation, situation gets worst. The problem was minimized when we have improved solder paste volume from inner row pads and reduced outer row pads. However, problem was not complete solved.

Has anyone faced issues with this kind of component?

References: Supplier Supplier p/n SMSC ECE5048-LZY SMSC MEC5055-LZY-AVA00 SMSC MEC5055-LZY-AVA01 SMC ECE5048-LZY SMC MEC5075-LZY-SAL00 MICROCHIP MEC5085-LZY-HST01

Regards

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#73651

DQFN INSUFFICIENT SOLDER / HEAD ON PILLOW | 6 March, 2015

Hello Adriano,

I see that you have ran several test with differnt valumes of solder paste which is a reasonable path. Have you run any solderability tests? Head in pillow is usually considered a solderability problem. Also, what type of plating are the component leads treated with?

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#73654

DQFN INSUFFICIENT SOLDER / HEAD ON PILLOW | 6 March, 2015

So far we have tried diferent date codes, solder pastes and PCBA models (same component used in different projects). We have also sent some components for plating analysis and we are waiting the LAB feedback. Additionally, we have tried components with and without baking even with Humidity indicator inside the target. The most strange point is that issue only occurs on the inner row pads. Important to highligth that thermal via design recommend from supplier has been followed.

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#73655

DQFN INSUFFICIENT SOLDER / HEAD ON PILLOW | 6 March, 2015

Hello,

I see you checked your options in stencil design, but did you check the pad design on the board itself? May be the board has to be fixed. We run some dual row QFNs and never had a problem. I would examine the pad design and the finish of the board.

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