Gabi What is your base material ? Jim Douglas ---------- From: Eltek Ltd. - Process Engineering[SMTP:[log in to unmask]] Sent: 11 June 1998 07:32 To: [log in to unmask] Subject: Re: [TN] shadow plating electroless ni au Gabi , 3 basic possibities for such shadows : 1 ) Catalyst ( Palladium ) adsorbed on epoxy causing initiation of Nickel plating followed by Gold 2 ) Unproper rinsing during plating process causing drag-out of chemistry in concaves around pads . 3 ) Less likely , but still possible : residues of unetched basic copper arround circuitry . Best regards from Cyla and Boaz . Call us if You need any assistance with examination of such boards . Edward At 22:11 10/06/98 +0300, you wrote: >Hello, TechNetters! >Some questions about electrolessNi/Au plated circuits: >What is the cause of shadow plating between the pad and the surrounding >solder mask? >Is it acceptable by IPC standards for Class2,3 if it extends to 30% of >the distance between the >fine pitch lands separated by ~4mil solder mask? >It seems that the presence of the solder mask near the plating area >enhances the occurrence of >the phenomenon. >Also, we see differences in the appearance of the fine pitch area >between two different manufacturers. >One of them gives us very clearly defined pads without any shadowing , >the other-shadow plating >along the long edges of the pads, for the same artwork. >We are concerned about violating the IPC requirements ,about the >necessity of solder mask >between the pads with less than 20mil pitch and about shorts after >reflow soldering. >Please answer me as soon as possible. >Thank you in advance for your help, >Gaby > >################################################################ >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 technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 >################################################################ > > Edward Szpruch Eltek Ltd - Israel Tel 972 3 9395050 Fax 972 3 9309581 E-mail : [log in to unmask] ################################################################ 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 technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################