How to create a fab drawing with drill charts for blind and through vias.
The example fab drawing shown below has four pages.
The pages frames and fab notes are not shown in the screen shots to hide confidential data.
Page 1 has the Stackup and Fab notes.
click on images to view
Page 2 has the Drill table and Drill Chart for Layer 1 to 16.
Page 3 has the Drill table and Drill Chart for Layer 1 to 8
Page 4 has the Drill table and Drill Chart for Layer 9 to 16
How it was done.
I used three mechanical layers to display the via symbols above the drill charts.
Note the drill table is placed only once on the Drill Drawing Layer in the design.
Outjob setup for PDF Fab Drawing with three drill tables and charts.
Example for Layer 1 to 8 blind vias.
Choose the drill layers Start = L1 and Last = L8.
Example for Layer 9 to 16 blind vias.
Choose the drill layers Start = L9 and Last = L16.
That's It !
Fab Drawing
To prevent Red Hash from Appearing in the Fab Dwg of a DNI Variant uncheck the Include Components for the Top and Bottom (as shown below).
Fab drawings often include design technology notes. The technology notes are used to identify the most advanced and challenging features within the design.
Typical Design Technology Notes include:
Minimum Trace Width.
Minimum Trace to Trace spacing.
Minimum Via Drill and Pad Size.
How would we find these minimum features in Altium ?
We can use a combination of 'Find Similar > 'PCB Filter' and 'PCB List' to find and identify the minimum size design features.
For example to find the smallest Via Pad size:
Start by selecting any small via in your design and use Find Similar.
click on image to to view
As shown above select 'Same' for Via Diameter. Note that the Create Expression and Run Inspector options are checked.
Shown at bottom of the PCB Inspector panel are the number of Vias found that matched the search criteria.
Nice, however recall what really want to know is what is the smallest Via pad size used in the design. Using Find Similar was a great way to get started and create a PCB Filter Expression with the proper syntax.
Next we modify the expression in the PCB Filter Panel to search for any Vias that are smaller. This is easily accomplished by changing the = 18 in the above example to < 18 and selecting apply.
(ObjectKind = 'Via') And (AsMils(ViaDiameter) < 18)
Looking again at the PCB Inspector Panel, we see there is a smaller Via size of 17mil used in this design. As shown at the bottom of the panel 44 objects are displayed.
Note if the Via Diameter size in the Inspector was displayed as <...> then there would be more than one Via size found with pad diameters of less than 18mil.
The steps shown above are useful to identify where in a design the smallest pad is used. In this example the smallest Via pad size of 17mil was used in 44 places to route a 0.75mm BGA.
We can also use the PCB Filter > PCB List (sorted) to find the smallest Via features for drill and pad sizes.
Using the same methods as described above you can identify the smallest line width.
For minimum Trace to Trace spacing refer to your design rules.
