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 > > -------------------------------------------------------------------------------- - > DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF DesignerCouncil. > To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL > Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > -------------------------------------------------------------------------------- - > --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------