Courtyards for Inch 0402, Metric 1005, in 2014.06

The courtyard excess change from 0.15 mm to 0.25 mm was a programming mistake and it is being fixed right now in a V2014.06 sneak release that will be posted soon. Great catch! And thanks for reporting this typo.

The important update was that the original "Toe" goal was 0.20 mm for all parts less than 1.6 mm length.

IPC is drafting a new standard that replaces IPC-CM-770E called IPC-7070 Component Mounting Issues and Recommendations of which I am the co-chairperson.

I was at IPC headquarters the week of July 14 with Dieter Bergman and I locked in a conference room for 3 days rewriting from scratch the IPC-7351C Land and Pad Pattern Development Issues and Recommendations and teleconferencing daily with the chairperson of the IPC-7070 in Berlin Germany.

Out of that committee meeting, the most significant change was to address tomb-stoning of micro-miniature chip components less than 1.6 mm length. The 0.20 mm Toe was too robust for the 0402 and the 0201 is 50% smaller and the 01005 is 50% smaller again. So we first had to develop an acceptable Toe goal for the 0402 and the 0.15 mm Toe value was accepted. Then we had to figure out what would be the minimum Toe for any package regardless of it's size and that value was set at 0.10 mm for the 01005 package. Then the 0201 was set in the middle at 0.12 mm Toe.

Thinning the paste mask stencil is also required but that information will reside in the new IPC-7070.

Any data in the existing IPC-7351 pertaining to assembly attachment is being relocated in the IPC-7070 standard and the two new documents refer back and forth to each other.

I should also note that the IPC-7251 for through-hole technology is being added to the IPC-7351C so there will only be a single standard for all Land Pattern Guidelines for SMD (Surface Mounted Device), IMD (Inserted Mounted Device) and UMD (Unpackaged Mounted Die).

PCB Libraries, Inc. prides itself in implementing the latest technology into our tools as fast as possible rather than waiting for the standards release date, which will not happen for another year due to all the upcoming committee meetings at SMTA in Chicago, IL, APEX in San Diego, CA and the necessary committee approvals that need to be reviewed and signed off by unanimous vote.

Thanks, the sneak release has the courtyard set correctly to 0.15 mm for NOMINAL for these chip components, however I noticed that it is also 0.15 mm when you change the environment to MOST and LEAST rather then changing to 0.20 mm (M) or 0.12 mm (L).

Also the PADS ascii outputs are different from before for the courtyard.

In 2014.05 for Nominal, distance from pad edge to centre of courtyard line is 0.15 mm, courtyard line width is 0.05 mm (default setting), distance from pad edge to first edge of courtyard line is therefore 0.125 mm.

In 2014.06 Sneak Release for Nominal, distance from pad edge to centre of courtyard line is 0.18 mm, courtyard line width is 0.05mm (default setting), distance from pad edge to first edge of courtyard line is therefore 0.16 mm.

I am guessing that the software is now compensating the courtyard line so that the inner edge is at the 0.15 mm rather than the centre of the line, and that it's rounding outwards to suit a particular grid with 2 decimal places.

I did restore user defaults, and courtyard place round is 0.01.

Can you confirm if this is now correct to standard with the PADS ascii output?

Thanks for the background.  The micro chip components are the ones I like to update when I see things have changed because these can cause the most issues with PCB assemblers.

Thanks for the explanation.  Clears everything up.