Susan,

As you have seen, many fab suppliers believe they can deliver 4 mil line and space PCB's. OK,
so what is your question concerining reliability.

This issue differs somewhat from what reliability really means. Please clarify. If only to
determine supplier capabilities, look at IPC, and other, design standards and fabrication
specifications and determine what is possible - as line and space dimensions and tolerances
(big issue for consistency) in what yields, at what cost. In other words, it is possible to do
1 mil line and spacing once out of maybe 100 boards (single, double, or multiple sided
boards?).

We are all headed toward finer lines and spacing. However, many engineers and designers prefer
placing much of the "fine line" circuitry on chips, MCM's, hybrids, or other mountable
components - then place them on PCB substrates with less density acting as the support
mechanisms they really are.

Earl Moon

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################