Reply to:   RE>BGA
Doug:

I don't see it as a fabricator issue, except maybe for flatness of the pads for
the balls.  The pitch of the BGA contacts is less than that of fine-pitch SMT
and solder mask can easily fit between the pads on the PCB for a solder "dam". 
Placement augmentation due to high HASL deposition should be considered.

It is the DESIGNER that must route traces to the BGA package, even to the inner
balls of the IC.  It might involve vias to inner layers and zig-zag traces to
get the inner signals to the other components on the PCA.

It is the ASSEMBLER that must address the process of placing and soldering the
BGA package(s) to the PCB.  It MIGHT involve X-ray inspection to assure
complete attachment of the inside balls, since they cannot be visually
inspected.

Weigh all of your options before you choose BGAs for your designs.  Once
committed, there is a considerable investment to be made by your assembly
facility (if they don't already have it) to deal with it and inspect for the
quality of that assembly.

Bill Fabry
Truevision
[log in to unmask]

--------------------------------------
Date: 1/10/96 5:37 PM
To: Bill Fabry
From: MR DOUGLAS C JEFFERY
-- [ From: Doug Jeffery * EMC.Ver #2.10P ] --


Question?

What does BGA technology mean to board fabricators?  Do we have to
become solder paste experts and reflow solder again.. I thought we got
rid of that problem.....:)....

  No Seriously, what are the responsibilities at fabrication for
creating boards to accept BGA's?

Thanks?

Doug Jeffery
Electrotek..
 


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