Sherif; We've been laser drilling since 1997, and we laser drill .012" diameter vias from layer 1 - 3 on a daily basis. Our typical laser vias are 5 to 6 mil diameter vias for layer 1 to 2 connections, and 10 to 12 mil diameter vias for layer 1 - 3 connections. We have even laser drilled 16 mil diameter vias down to layer 4 for one of our customers. This hole size and depth are no problem for a laser drill, either Uv alone, or Uv/Co2 combination. Dave Simonik Laser Process Technician Sanmina-SCI Corp. Owego Division -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Sherif Refaat Sent: Tuesday, November 20, 2007 2:47 PM To: [log in to unmask] Subject: Re: Laser drilling limitations Lee and Dwight; Thanks for your response. I understand your point. However my question is regarding diameter and depth not the aspect ratio (though I understand they are related). In a specific application the hole dia. is 0.013" and the depth is 0.009" so the aspect ratio is below .7 : 1. Would such a relatively large hole be OK for Laser drilling. There are other smaller holes 0.006" dia. and 0.004" depth on the same board which are OK to Laser drill. But the designer is asking for the larger ones also to be Laser drilled (instead of other methods of drilling the holes) to save on cost and stream line the process. Sherif, ----- Original Message ----- From: "Dwight Mattix" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, November 20, 2007 2:10 PM Subject: Re: [TN] Laser drilling limitations > Well and simply put Lee. I concur. > > Add to the bare pwb plating concern a concern about solder joint > acceptability for uVia in pad. As the uVia aspect ratio increases past > 0.5:1 the likelihood of voids in solder joints increases. > > The shape/slope/quality of the uVia wall and quality of uVia plating > becomes critical. It gets more difficult to maintain uVia form that > assures solder quality. > > Put another way, the solder joint becomes increasing sensitive to uVia > shape and roughness. It becomes increasingly likely you'll have > unacceptable solder voids due to outgassing from the uVia. > > If it wasn't such a huge distribution I'd attach some photos to illustrate > the effect. > > > dw > > > At 08:37 AM 11/20/2007, Lee parker wrote: >>Sherif >> >>The real issue with laser drilled holes is plating the via which is >>usually >>blind. Aspect ratios above 0.8 become a challenge which is even more >>impacted by the diameter of the hole. The hole you suggested has a aspect >>ratio of 1.0, the quality of the plating will be problematic. >> >>Best regards >> >>Lee >> >>J. Lee Parker, Ph.D. >>JLP Consultants LLC >>804 779 3389 >> >> >> >>----- Original Message ----- >>From: "Sherif Refaat" <[log in to unmask]> >>To: <[log in to unmask]> >>Sent: Monday, November 19, 2007 10:18 AM >>Subject: [TN] Laser drilling limitations >> >> >> > Hi Technetters; >> > >> > What is a practical maximum via hole diameter and depth manufactured >> > using >> > Laser ablation? I would say these should be 0.006" and 0.006". Any >> > different >> > opinions? >> > >> > Sherif, >> > >> > --------------------------------------------------- >> > Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> > 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 >> > 847-615-7100 ext.2815 >> > ----------------------------------------------------- >> > >> >>--------------------------------------------------- >>Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>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 >>847-615-7100 ext.2815 >>----------------------------------------------------- > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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 > 847-615-7100 ext.2815 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. 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