[PCB_FORUM] Re: .8-MM BGA Geometry

Nice breakout... can you do it for .5mm pitch?

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx 
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Jim Goshorn
Sent: Wednesday, September 14, 2005 7:26 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: .8-MM BGA Geometry



        Hi Rich,

 First of all, you should explain to your customer that by selecting this type 
of package that they
will be taking a PCB cost hit. It will either be because you choose to use 
blind and buried vias or
pin in pad, which I don't recommend as it will be a problem for your assembly 
house. Or fineline
with reduced via size on your BGA symbols. Often times you will need to 
increase the layer count
just to break out of these devices successfully when the rest of the board may 
not require it. And after
you raise all of these fine arguments he will tell you that he has no other 
option anyway.
This is how I designed my last .8mm board a few years ago, good luck.


19f4ec67.jpg


19f4ecb5.jpg

finished hole size = 8

19f4ecd4.jpg



At 06:27 PM 9/13/2005 -0400, you wrote:



Dear Forum,

 

My Client is utilizing a 0.8-MM SDRAM Package.

 

The smallest BGA Pitch I have dealt with so far is 1.0-MM.

 

The Fabrication/Assembly Vendors are yet to be determined.

 

The PCB "target" construction is 0.062-Inch 14-Layer, three sets of dual 
embedded stripline. No Blind/Buried Vias (all Thru Via).

 

Questions:

 

1.    Any recommendations for local (NH-MA) Fabrication/Assembly Vendors 
capable of working with this BGA Geometry?

2.    BGA SMT Pad Diameter?

3.    BGA SMT Soldermask Diameter?

4.    Thru Via Drill?

5.    Thru Via Pad Diameter?

6.    Alternatively, is Via-In-Pad an option?

7.    Any chance of ATE Testing 0.8-MM Pitch?

 

Thank You,

 

Richard E Marion

169 Little Mill Road Unit 2

Sandown NH 03873-2554

HOME: 603-887-2266

CELL: 603-247-1610

FAX : 603-887-2936

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