I appreciate the comments from Glenn Heath (Merix), I think it definitely worth more than just 2 pennies. :) The experience that Glenn shared proved what I'd mentioned in my message: different manufacturers, having different setup, equipment, may come to different conclusions about the economics of processes. However, the important conclusion from our discussion is: "We both agree that microvia (blind via) can be a cost saving solution to achieve higher density." If I'm not mistaken, I believe the design rules for the microvia are pretty much the same for either plasma or laser drilling (.005"-.006" diameter, .012"-.016" pad). I think it would be nice if we can all agree upon a set of design rules such that the boards can be made by either technologies. That way we can get rid of the 2nd source suppliers issue, which is a big concern from the designers especially on new technologies. Any speculation about which technology is going to take over the market is meaningless unless there is a market. Mason Hu Zycon Corporation ______________________________ Reply Separator _________________________________ Subject: RE: Plugged Vias (and laser vias and plasma vias) Author: [log in to unmask] at corp Date: 10/17/96 8:11 PM Both Mason Hu and John Gulley make valid points about via in pad techniques, but I thought I should throw in Merix's 2 cents on the matter as well. Mason is right in his statement that laser vias are not always slower and more expensive than other methods. He is definitely right in his statement that the use of microvias can make the part less expensive than conventional (drill vias) boards through layer reduction. I would add that microvias often make boards less expensive through size reduction through the increased density which is made possible by putting vias in pads. A critical cost factor in comparing the various microvia methods is the number of vias in pads. If the number is low, laser may be the most economical and fastest method (unless it is not done in-house; then shipping takes time). Because processes such as DYCOstrate (TM) [plasma defined vias -- the process that John mentioned that Merix is using] are batch processes, boards with a significant number of microvias are less expensive than laser defined via boards. Merix defines it as "buy one via, get the rest free". Because plasma etchers are more common at board fabricators than lasers, the plasma defined via process has a greater chance of being performed in-house and is therefore often quicker regardless of the number of holes. Mason's statement about Japan using SLC (IBM-Japan's process) and laser is valid, but not surprising considering the plasma defined via process was developed in Switzerland. In Europe, the plasma defined via process is more popular. This is similar to the trends of immersion gold acceptance in Europe versus OSP acceptance in Japan. I would say that comparing the pricing of laser via boards to plasma via boards has not been very thoroughly investigated. Mason may have been comparing Zycon's pricing to HP-Germany's pricing and if that is the case you would have to factor in duty, shipping, and exchange rates as well as board fabrication cost. For the designs that Merix has seen, the DYCOstrate (TM) process has been the most economical method of producing microvias. As a whole, microvia technology has advanced very rapidly over the last few years and is worth investigating by anyone who is interested in reducing size, weight, and cost. Its use should not be limited to the issue of plugged vias. Glenn Heath Merix Corporation 503-359-2652 [log in to unmask] *************************************************************************** * 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. * *************************************************************************** *************************************************************************** * 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. * ***************************************************************************