Ryan After looking at these pictures I would agree with Werner that the drilling is not the greatest. I am even more concerned about the appearance of the copper in the first picture. This has many of the earmarks of a high plating density. This reduces cost, but at the expense of copper uniformity and ductility. Best regards Lee J. Lee Parker, Ph.D. JLP Consultants LLC 804 779 3389 ----- Original Message ----- From: "stephengregory5849" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, April 22, 2008 6:53 PM Subject: Re: [TN] Via barrel cracks > Hi Ryan! > > Have your pics up! They're at: > > http://stevezeva.homestead.com/files/Via_Barrel.jpg > > http://stevezeva.homestead.com/files/Via_Barrel_2.jpg > > http://stevezeva.homestead.com/files/Via_Barrel_3.jpg > > Steve > > ----- Original Message ----- > From: "Ryan Grant" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Tuesday, April 22, 2008 5:08 PM > Subject: Re: [TN] Via barrel cracks > > > Steve, > > I would much appreciate your help with posting these pictures. > > Thanks, > Ryan > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin D Asbell > Sent: Tuesday, April 22, 2008 3:55 PM > To: [log in to unmask] > Subject: Re: [TN] Via barrel cracks > > Would you have an image for posting? > > > =================== > Hi Technetters, > > I have a case of via barrel cracks (E crack) and I would like to know > possible causes. > > The crack is circumferential and occurs at the center of the via. The > hole appears smooth, i.e., no glass nodules or tearout and there is > neither positive nor negative etchback. Of course there is some > wicking, but only about 25um max. The copper thickness is 20um at the > crack and roughly 35-40um at the knee. Although, at the initiation > point of the crack, the copper thickness is only 10um, but that could be > due to stretching and subsequent thinning of the copper. Around the > periphery of the crack are micro-voids in the resin about 30um. It is > triangular shaped, so I can't tell if it is resin recession or a > laminate crack. > > In other words, this via pretty much looks normal, except for one thing, > which might be an artifact of stretching and cracking of the via. For a > span of about 60um on the vertical of the via, at the crack, there is a > roughness that slightly reduces the copper thickness. The surface of > the copper at this point appears both rough and black in color. > > This board has seen two reflows and a hot functional test before final > failure. > > The board shop's initial response was speculation of the OSP soft etch > attacking the copper, but this particular via has solder mask plugging > both sides of the via; therefore chemicals after solder mask cure can > not get into the via. > > In case it matters, at one time, we have had occurrences of this board > shop "re-working" panels after copper plating by placing the panel in a > tank of etchant, then re-running the board through copper plating. > (They do panel plating). > > I'm a little suspicious of their FA, so I would like some independent > opinions and places for me to dig into. > > Thanks for any help, > Ryan > > --------------------------------------------------- > 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 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