Hi Victor, The problem with an evaluation without microetch is that it is so easy to smear the copper and cover the crack. With too aggressive and microetch everything looks like a crack. What you do is perform a moderate microetch and then compare the electroless lines at the corner of the hole, at the base of the microvia and plating on top of the target pad. If anyone of those lines is darker then the others consider that line a crack. Sincerely, Paul Reid Program Coordinator PWB Interconnect Solutions Inc. 235 Stafford Rd., West, Unit 103 Nepean, Ontario Canada, K2H 9C1 613 596 4244 ext. 229 Skype paul_reid_pwb [log in to unmask] -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: March 9, 2012 1:30 PM To: [log in to unmask]; Paul Reid Cc: [log in to unmask] Subject: RE: [TN] RE: HDI PCB - micro-via I always do copper integrity evaluation Pre and Post etch on all cross section sample. The Pre is for IP separation. Victor, -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid Sent: Friday, March 09, 2012 12:18 PM To: [log in to unmask] Subject: Re: [TN] RE: HDI PCB - micro-via Hi Mei and Inge, Inge - I noticed that you referred to a report I wrote but I didn't see a link. You are free to use anything I have published so there is no problem. I am curious as to which report you are talking about. Mei - I think that these microsections appear OK but... 1. The first picture is of a dielectric filled and capped microvia but the section is not to the center of the microvia so the width measurements may appear to be less than they are in reality. There may be a crack between the base of the microvia and target pad. It looks like there maybe a crack in the flash plating at the base but it is hard to tell. 2. This appears to be a copper filled microvia with a crack in the upper right corner. Again I don't know if the microsection is ground to the center of the microvia. 3. This appears to be a copper filled microvia with a large microetch into the target pad (almost through the target pad plating). 4. This appears to be a dielectric filled microvia but it is not ground the center. 5. This is a picture of a buried via without a cap. I personally think you should evaluate microsections after a microetch (which has been done here). Sincerely, Paul Reid Program Coordinator PWB Interconnect Solutions Inc. 235 Stafford Rd., West, Unit 103 Nepean, Ontario Canada, K2H 9C1 613 596 4244 ext. 229 Skype paul_reid_pwb [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord Sent: March 9, 2012 10:52 AM To: [log in to unmask] Subject: Re: [TN] RE: HDI PCB - micro-via Hi Mei, Have you used a chain saw? I've been investigating thousands of vias, and I think I'm right when I say that you can't get reliable and useful information if you don't polish correctly. Start with grit 600 for a few seconds, then 1200, 2500 and 4000. Use rotating sample holders to avoid smearing of copper. After polishing, a light dip in a copper etchant and then DI rinse. Yeah, it's a boring job, but you will find that the analysis becomes more interesting. AND.....read the below report of Paul Reid (he may see this, hope he won't accuse me for copyright trespassing). See the difference between the poor prepared samples and the correctly prepared ones. Read the whole paper and you will learn LOTS! Good Luck! Inge On 9 March 2012 13:25, Steve Gregory <[log in to unmask]> wrote: > Hi Wee Mei! > > > > I have your pictures posted: > > > > http://stevezeva.homestead.com/first_microvia__1-2_.jpg > > > > http://stevezeva.homestead.com/2nd_microvia__3-4_.jpg > > > > http://stevezeva.homestead.com/microvia-1__9-10_.jpg > > > > http://stevezeva.homestead.com/microvia-2__9-10_.jpg > > > > http://stevezeva.homestead.com/buried_via.jpg > > > > Maybe some Technetters can steer you in the right direction.... > > > > Steve > > > > > > From: Lum Wee Mei <mailto:[log in to unmask]> > > Sent: Thursday, March 08, 2012 7:04 PM > > To: Steve Gregory <mailto:[log in to unmask]> > > Subject: HDI PCB - micro-via > > > > Steve, > > > > I have never inspected any HDI PCBs before and was asked to perform > inspection to them in accordance to IPC-A-600 and if necessary IPC-6012. I > have no idea what I am looking for as I stare at those pictures which I > randomly took from two of the cross-section buttons. I flipped through the > whole IPC-A-600 and 6012 but not able to see any images/pictures that > correspond to what I see. Also am I suppose to use 6012 or 6016 to assist > in the inspection criteria? I am totally lost. > > > > Kindly post the pictures to TechNet so that some kind souls can help me > out of this dark tunnel. J > > > > Thanks and regards, > > ~wee mei~ > > > DSO 40th Anniversary - Celebrating 40 years of Serious Fun. 1972 - 2012 > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________