Hello, James. Nice to see you here!
I have found the additional charges for blind vias from different fab shops
to vary from very little all the way up to 500%. While I realize there are
extra steps and processes involved with blind vias, I don't believe the
additional cost should be calculated as a multiple of the overall job. I
have found that it makes no difference if you have 1 blind via or 500 of
them. (Blind vias can be laser drilled at > 300 per second!) A standard,
reasonable charge for blind vias is acceptable; simply doubling, tripling,
(or worse) the cost of the board, regardless of size or other factors, is
not.
Ray
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of James
Jackson
Sent: Wednesday, April 04, 2001 3:41 AM
To: [log in to unmask]
Subject: Re: [DC] Blind and Buried Vias
Good morning Ray,
Many moons ago, I designed a board that required Blind Via technology.
It has been a long time ago, but if memory serves, the generic rule of thumb
was, Blind Via Boards cost about twice as much as Through Via Boards - due
to
their needing twice as many drilling operations.
But - don't quote me on that.
Regards,
James Jackson
Oztronics
http://joj.home.texas.net/
> Thanks, Jack, for your input. (Long time, no talk to!) Designing with
B/B
> vias is not the problem; getting a reasonable, standard cost differential
> from PCB fabricators is the problem. IMO, designers are reluctant to use
> B/B vias and some fabricators charge excessive prices for them,
especially,
> laser drilled blind vias. Everyone continues to consider the use and
> fabrication of B/B vias as 'new technology'. Anything that's been around
> this industry for over a decade is not new. I am very frustrated with PCB
> fabricators for not keeping up with the industry they are a part of and
> support.
>
> We are starting to design with .5mm pitch, .3mm pad CSPs. This doesn't
> leave room on the inner pads for anything except in-pad, micro vias. This
> is especially true for PCBs in the 2 to 6 GHz range.
>
> I have asked several vendors for a cost factor to consider when using
blind
> vias, getting less than satisfactory responses. I have posted my question
> to both the DC (640 subscribers) and TN (1242 subscribers) forums, getting
> the same results. It goes beyond interesting, Jack.
>
> Ray
>
>
> -----Original Message-----
> From: Olson, Jack [mailto:[log in to unmask]]
> Sent: Tuesday, April 03, 2001 10:45 AM
> To: 'DesignerCouncil E-Mail Forum.'; 'Ray Humphrey'
> Cc: [log in to unmask] ORG (E-mail)
> Subject: RE: [DC] Blind and Buried Vias
>
> I would like to contribute Ray, but I have only had to use blind/buried
vias
> once in my life.
> I can tell you from a design point of view in Veribest it is effortless,
you
> just state the range of layers for each via type, use vias wherever you
want
> (whatever type you need) and the computer takes care of the rest (multiple
> drill files, fab dwg layers, etc)
>
> Its not that I am reluctant to use them, I just rarely see a need (yet).
> We are using 1mm BGAs on .093 thick boards with no problems with regular
ol'
> vias
>
> But I have absolutely no idea how to evaluate the cost difference, since
> there is no way to get a "multiple quote" on a design that would prove
> anything. Can't you just ask a couple of fab vendors what to use as a rule
> of thumb for cost-adders?
>
> It IS interesting that absolutely no one knows this,
> or is willing to share anything about it, hmmm?
>
> Good Luck,
> (onward thru the fog)
>
> Jack
>
> -----Original Message-----
> From: Ray Humphrey [mailto:[log in to unmask]]
> Sent: Saturday, March 31, 2001 11:47 AM
> To: [log in to unmask]
> Subject: [DC] Blind and Buried Vias
>
>
> In a recent posting, Your Opinoin Needed - Designers Learning Symposium, I
> notice that blind and buried vias were included in the 'newer
technologies'
> category. I also find that most designers are reluctant to use blind
and/or
> buried vias, for various reasons. Blind and buried vias have been around
> for over a decade, they are not new. I have a great article from the
March
> 1988 issue of PCD magazine talking about the use of blind and buried vias
> down to 2 mils in size! I am frustrated that PCB fabricators are failing
to
> keep up with the industry they support and continue to charge excessive
> prices for such an old process. Much of today's technology require the
use
> of blind and/or buried vias - I say it is time for designers to get over
> their paranoia and for fabricators to stop taking advantage of it!
>
> Several days ago, I posted this question to the DC forum, "Could someone
> please give me a general guideline concerning the additional cost of using
> blind vias on a PCB? Perhaps there is someone out there in the PCB
> fabrication business or a fellow designer that has done some extensive
> research into this?" To date, I have not received a single response.
>
> Isn't it time we stopped considering blind and buried vias as a 'new
> technology'?
>
> Just my rant - I feel better, now. :)
>
> Ray
>
>
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