Brian McDermott made the comments: "Unfortunately, the diversity of micro-via technologies, the confusion on the pro's/con's and the absence of a low cost process with multiple established suppliers, has prevented large scale implementation of micro-vias." Which I agree wholeheartedly. The solution that he seemed to suggest was for every board shop to convert to their way of making boards. I keep trying to make the point that different board manufacturers are setup differently and what's right for them may not be right for your or me. I think we should let the market decide what is the best. We can keep going back and forth about the pros and cons, but that's only going to give potential users the feeling - "maybe we should wait until things settled down". What's important here is how to reslove the confusion. It is possible that photo dielectric may result in different electrical properties. However, I think plasma and laser can use similar and more traditional material (resin coated foil, or Thermount reinforced laminate) to avoid functional differences. (Glenn, I probably have to ask you to comment on that again! :)) Maybe this is the reason the previous discussions were focused on laser vs. plasma - because they are much more alike. I think the "Typical" numbers suggested by the folks from IBM seem like something that all technologies can support (based on Glenn's numbers and our numbers). So, for you designers out there, if you want flexibility (as suggested by Glenn) choose "Typical", if you are more adventurous then sky is the limit. Minimums(mils) Typical Available Limited Availability --------------------- ------- --------- -------------------- Line Width 3 3 2 Line Spacing 5 3 3 Photo Via Diameter 5 5 4 Photo Via Land Diameter 12 10 6 PTH Diameter 14 10 8 PTH Land Diameter 24 18 14 I would like to encourage other board manufacturers, whichever technology you are working on, to comment on whether this is a reasonable set of design rules. There are several factors determine the success of a product/process. Price, quality, reliability, availability all come into play. I think everyone agrees he/she has the best quality and reliability. Apparently, everyone think his/her price is the best in the world, also. Availability is the key to jump start the market. With a set of common design rules in place, the customers can take their design and ask for the lowest bid, whichever technology it maybe. This is the best way to resolve availability issue. The response from Mike Avery clearly supported my view. I'm sure when the market is up, there will be big enough shares for everyone. Mason Hu Zycon Corporation *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************