[SI-LIST] Re: Fab capabilities

  • From: "Kai Keskinen" <kalevi@xxxxxxxxxx>
  • To: <sunil_bharadwaz@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
  • Date: Wed, 6 Dec 2006 18:36:12 -0500

Sunil:

A standard via aspect ratio is 10. That is the ratio of via diameter to via
length (usually board thickness unless we are going to blind and buried
technology). Almost all fab houses can do this easily. As the via aspect
ratio increases, the yield drops. Some FAB houses can go higher but the
costs go up because yield of bare boards goes down and inspection costs go
up. An aspect ratio of 12 is pretty easy for most high end shops and some
can do 15 but it costs you a lot.

A standard line width in any decent shop is 4mils in half ounce copper. If
you want to get thinner, the quality of the shop increases and yields go
down so costs go up quickly. A two layer board means you are routing on the
outside so plating thickness will limit line width.

There are a number of PCB Fab sites from  both fab houses and communities.
Why not check them out? Googling is a wonderful way to find out a lot of
information.

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of sunil bharadwaz
Sent: Wednesday, December 06, 2006 12:50 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Fab capabilities


Hello friends ,

  We have a BGA chip with 0.3 mm pitch & 0 .1 mm ball dia.
  Obviously it is difficult to route the inner row balls.Targeting
  a two layer card.

  I wanted to understand

  1)What is the smallest Dia  Via & pad possible with the Fab houses.
  2)Thinnest tracks possible & the min clearances required.
  3)List of Fab houses who have these kind of capabilities
    (Any where in the world).

  Appreciate any help in this regards.Thanks !!

  Best regards
  Sunil B

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