Waheed, A simple two layer board would consists of top and bottom copper layers. These are layers where you draw your pads and wires. On top of this (both sides) you place a mask, which is mainly for protection. On these layers you have openings only for the pads (TH and SMD). Paste layers are used when you have to solder SMD components using reflow process. On this layer you should see only the SMD pads. It's mainly applied for the top layer but if the PCB is double reflow, they'll ask you to provide solder paste on bottom parts, too. The dimensions of the pads in paste layers could be the same size as the pads in copper layers or a little bit less. Assembly companies could adjust them accotding to their needs. So, the paste layers are not important for PCB manufacturing but for assembling the PCB.
Hope this helps. Mira --- Waheed Bajwa <[EMAIL PROTECTED]> wrote: > Well Ian thats a lot of useful information and of > great help to me... and > thanx for the link too... > > Just a few clarifications... > > So the overlay layer and the silkscreen layer is the > same thing... > Looks like the mechanical layers are not invovled in > the manufacturing of > PCB and just for reference only? no conduction? > > I get what is Solder Mask layer but what I don't get > is why do we need paste > layer after this? I blv both are almost the same > thing... There would be > holes in the solder mask layer and there we can > apply the paste even if its > the case of surface mounted components... Please > explain... > > Best Regards, > Waheed Bajwa __________________________________________________ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
