Mark Simmons wrote: > > > > Some of the advantages to HAL are: > 1. Solderability. Nothing solders like solder. Absolutely, probably HASL best advantage. > 2. It assures the solderability of the plated copper and previews > general thermal fitness prior to component attachment. > 3. Excellent shelf life. Better than a year in normal conditions (like > your desk drawer) > 4. Less contaminants like Cu in the solder joint. (since Hal establishes > the inter-metalic, you attach to solder.) > 5. Plated thru holes sure solder nice. (have we gotten rid of those > pesky holes yet?) > some of the dis-advantages are: > 1. Planarity. Somewhere around 6 to 8 mil pitch, it gets a bit > difficult to control thickness. (the process is geometry dependant) > > With respect to BGA's, with modern HAL equipment, they are being > processed routinely worldwide. > > With respect to Cleanliness, <3 mg. cl. sq. in. is routine on modern > equipment. You'd probably get < 3 mg Cl/in^2 even if you clean in ice cold tap water for 5 seconds. (m = milli) However, 3 micrograms Cl/inch^2 on HASLed boards, while do-able with modern PC fab equipment, is hardly routine except for the best fabricators. That is unless one measures ionic contamination with an unheated Omegameter with a test time < 4 min as is done by many PC fab shops. A lot of HASLed boards are pretty dirty, ionically speaking. ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################