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BGA Aperture

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aj

#50756

BGA Aperture | 20 June, 2007

Hi All,

Just a quick question in relation to BGA Stencil Aperture Design -

We currently use 1:1 ratio - are there any rules or benefits from over printing the PCB Pad ?

Replies appreciated.

aj...

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#50759

BGA Aperture | 20 June, 2007

Good afternoon,

You should use overprint technique if you have any problems with paste volume (PIH technology and mixed designs, for instance). Otherwise, it is useless. Overprint has to be made in such way so that paste would have an ability to flow back from mask to PWB pad. 0.2mm overprint works fine for 127/150um stencils. 1:1 BGA aperture is ok.

BR, Pavel

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#50816

BGA Aperture | 23 June, 2007

Hi,

We use 1:1 for 1 mm BGA and it works fine.

We used it at 4 thou laser cut stencils when we had a manual stencil printer, but have moved to 5 thou with the DEK and it works ok. We originally went to 4 thou because of paste release, but the DEK releases better without shear forces, so we can go a little thicker for more paste volume now.

Grant

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