hi, have you tried the 'american electroplaters society'? their web page is: http://www.aesf.org/ phil -----Original Message----- From: Adam Seychell [mailto:[log in to unmask]] Sent: Wednesday, January 30, 2002 12:10 AM To: [log in to unmask] Subject: [TN] pulse plating - without additives Hello platers. I am hoping someone here can share a few words of wisdom about reverse pulse plating. I'm having difficulty finding detailed information on the subject, as my local university library showed to carry almost nothing. It seems that the literature on reverse pulse plating is bound to research papers only (which I latter learned can be quite costly and time consuming to obtain). What I like to know is a method of plating "standard" printed circuit boards in acid copper bath *without* the use of additives. Pulse plating without additives has been done or so I've been told, however most documents I have read only talk about baths containing additives. Normally, a pure DC in acid copper (200 g/l H2SO4, 20 g/l Cu) would produce a rough and grainy deposit, especially when thickness' become high ( >35 um). The problem is aggravated by increasing current density. Even at current densities of 0.5A/dm2 the deposits still remain unacceptable. This is something I have observed through experimentation. A test panel was plated using reverse pulse technique to see what effect it had compared to DC plating at an equivalent average current density. Not having a proper pulse plating power supply I constructed my own basic one, using standard DC supply and an electronic circuit to periodically reverse the output. The parameters of the plating were: forward time = 5 ms reverse time = 1.7 ms forward & reverse current densities = 3 A/dm2 average current density = 1.5 A/dm2 The pulse plating deposits were only slightly improved over DC plating. A rough and crystalline surface was clearly visible under a 40X microscope. This does not sound promising and I am hoping this is due to incorrect characteristics of the current pulse. Most reverse pulse plating systems tend to use forward/reverse current ratios of around 3, forward times of 10~20ms and reverse times 1~2ms. Is important for the current reverse pulse to be short and high ? If anyone could guide me to right path I'd be greatly thankful. If there is no such thing as additive free copper plating for PC fabrication then kindly let me know as this could save me lot of time doing what others have already attempted. regards, Adam Seychell. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------