Hi Alexis, some aspects of our experiences with the technologies you asked for are listed below. "Alexis Meehan " wrote: > I would like to know if there are folks out there who are regularly > using blind/buried vias or via-in-pad technology. > * What is your experience (sucessful or not successful)? We have successfully applied this technology in a number of designs over the last 3 years. We have always specified thin prepregs e.g. 1080 as outer layers for their dimensional stability compared to RCC foil. An important issue is that the use of blind vias makes sense only in conjunction with buried vias. A copper thickness of 20µm on the hole wall of µvias is strongly recommended. On the wave side of the board we are even using standard 0.3mm through-hole vias as via-in-pad on 0603 resistors and SOP packages, and have been doing this for the last 5 years. > > * What is the minimum hole size you are using? 100µm for laser-drilled vias, 200µm for buried vias. > > * What are the cost increase or savings at the fab level and > also the assembly/rework level? The cost increase at the board level differs, but is in the range of 40% for a 1+6+1 board with buried vias from layers 2 to 7, compared with a standard 8 layer board. Cost savings result from the ability to design boards that have a high placement density on front and back sides, thus decreasing the size of the board. > > I want to get real-world feedback from those who have experience with > this. Thanks in advance for any info you can provide. > Best regards Volkmar Huß CID Engineering Electronic Circuit Boards Aufbau- und Verbindungstechnik _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ DRÄGER ELECTRONICS Draeger Electronics GmbH Moislinger Allee 53-55 D-23558 Lübeck Tel: +49-451-882-3998 Fax: +49-451-882-4365 mailto:[log in to unmask] Website http://www.draeger-electronics.com _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Important Notice This email and any attachment hereto are confidential and may contain trade secrets or may be otherwise protected from disclosure. If you have received it in error you are in notice of this fact. Please notify us immediately by reply email and then delete this email and any attachment from your system. Please understand that you are not allowed to copy this email or any attachment hereto or disclose its contents to any other person. Thank you.