To explain in a layman's term;

A long time ago, semiconductor mfg's produces IC's (Intergated
Circuits) in DIP (dual in-line package) package styles.  As
advancements of packaging technology and other
infrastructures, they started producing IC's in SMT package
forms (surface mount technology) which are:
- SOIC: small outline IC
- PLCC: plastic leaded chip carrier
- LCC: leadless chip carrier
- QFP: quad flat package
- SOT23: small outline transistor
and so on.

Without getting into details of SMT process, you can consider a
BGA (Ball Grid Array) package as a second level of SMT
packaging development.  A BGA is a retangular or square flat
body shape with numerous and tiny solder balls attached under
the body in a grid.  These tiny solder balls make
interconnections to PCB (printed circuit board).  The package is
tended to be more expensive than QFP's or PLCC's at this time,
but expect to be cheaper as the popularity of package increases.

Blind/Buried via's
Via's holes are connected thru from top to bottom sides of board
by drilling all the way thru.  A blind via is made half-way (less or
more) from one side of board, therefore you don't see the same
via hole from the other side.  A buried via as the name states, is
buried inside PCB, so you don't see the via hole from either side.

re.
mpark


>>> BKDoughty1 <[log in to unmask]> April 8, 1998  12:58
pm >>>
I need some very basic info on things that everyone here seems
to know about.
I'm feeling a little insecure (OK fine, I feel stupid asking but I don't
know
and want too) What are Ball Grid Arrays, do they replace IC's? Is
it more
expensive that other compatable parts.....will it drive up price if I
use
them. Are they only used for certain app.'s
I know it's alot of questions, also what actually is a blind or
buried via. Is
a buried via for internal layers only?

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