Eddies information is correct. Also, use IPC SM-840 for thickness call out. James Hofer Director of Operations Accurate Circuit Engineering 3019 S. Kilson Dr. Santa Ana Ca. 92707-4202 714-546-2162 work 714-473-6127 cell [log in to unmask] ----- Original Message ----- From: "Eddie Rocha" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, July 29, 2004 8:32 AM Subject: Re: [TN] LPI soldermasks > 1 mil (25 microns)minimum thick of LPI soldermask isn't achieved across the > entire bd with a standard LPI coating process. The thickness is less over > conductors. The thicker the conductor the thinner the LPI will be. With > standard outer layer conductor thicknesses (.5 oz copper plus .001" copper > plating) a .7 mil (~17 microns) minimum LPI thickness is typically achieved. > > As far as color, green is a standard color for fabricators. Changing the > color requires the fabricator to empty his LPI coating machine reservoir, > change screens, and in most cases change his tack drying oven temperatures. > These changes impact the fabricator's efficiency and reduces his thru-put. > > A matte or semi-matte LPI surface is believed to help reduce solderballs > during the assembly process. A glossy surface is hard on the inspectors due > to the excessive reflection under inspection lights. > > That's my input, hope it helps. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]]On Behalf Of Juan T. Marugán > Sent: Wednesday, July 28, 2004 11:29 PM > To: [log in to unmask] > Subject: [TN] LPI soldermasks > > > We are reviewing our documentation in order to avoid lacks or > misunderstandings in the requirements written in our drawings. > > At present we define: > > a)The type of soldermask: LPI iaw IPC-SM-840, Class H, > > b)Thickness: 25µm minimum > > c)Conductor finish: ENIG > > Apart from these requirements, we would like to know if other kind of > properties, like color (green, black...) and surface finish (gloss, semi- > gloss or mate) should be defined in the drawings. > > Can somebody give me some information about the influence of both > parameters -color and surface finish- in the quality of the assembled > board? That is, when or in which type of applications is important to > specify these parameters? > > We have also another question. Sometime we have had adhesion problems. To > check it, we performed a tape test. Is there another test to verify the > quality of the soldermask during incoming inspection? > > Thank you for your comments and best regards from Spain, > > Juan T. Marugán López > Production Quality > Defense Electronic Equipment > www.indra.es > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ----------------------------------------------------- > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------