All,

Does anyone have experience working with stacked DRAM?

We have been running into issues when reworking these part types.

From what I'm told, there are many types of stacks out there - and my
organization is currently purchasing/building with both value stacks and
performance stacks.  The differences between the two types of components
lies within their construction: the performance stacks have a film between
the two components and the value stacks have a small connecting device along
the lead edges, with minimal coating between the two DRAM.

When using our fairly basic rework equipment (AAT Hot Air Machines, Haako
hot air pencil, Metcal iron), we run into DRAM issues when reworking the
value parts - no issues with the performance.  We have already contacted the
DRAM manufacturer to verify whether or not they could recommend rework
equipment more suitable to dealing with these parts...  The manufacturer
recommended a shovel iron tip, reflowing one side at a time, until lifted.
Well, this works very well - when one has the real-estate to perform such a
repair...  but I'm dealing with minimal part spacing on our PCBs - and using
a shovel tip is not possible.

Any ideas?



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