BGA Breakout & Escapes

1. BGA Breakout & Escapes Steve Herbstman Technical marketing Engineer SDD February 2011

2. BGA Breakout & Escapes Please download : BGA_Breakout&Escapes.pptx Breakout_Demo.7z From the thumb drive provided. • Invoke .pcb and set display scheme to ‘breakouts’ • Explain that only one component at a time may be selected and therefore we don’t want the discretes on the backside of the board in view / selection. SLH, BGA Breakout & Escapes, Feb 2011

3. BGA Breakout & Escapes • Invoke Setup Parameters. • This is the sample 14 layer setup for this demo. SLH, BGA Breakout & Escapes, Feb 2011

4. BGA Breakout & Escapes • In this demo the micro-vias will be coincident (stacked) and the core vias will be PE/PE. SLH, BGA Breakout & Escapes, Feb 2011

5. BGA Breakout & Escapes • Critical Pad Entry Rule for Breakout setup. • The program will work without regard to these settings but later editing and DRC requires these. SLH, BGA Breakout & Escapes, Feb 2011

6. BGA Breakout & Escapes • Invoke Dialog from the route dropdown. SLH, BGA Breakout & Escapes, Feb 2011

7. BGA Breakout & Escapes • Window in on U2 (FPGA in the upper right). This is our breakout test case. SLH, BGA Breakout & Escapes, Feb 2011

8. BGA Breakout & Escapes • Breakout is broken into regions 1 thru 4. • Region 1 may go only a few layers into the stackup (ex 1:2 2:3 3:4). • Region 2 may go thru to the core vias. (1:2 2:3 3:12) • Region 3 is a ‘transition’ region. Shown later. • Region 4 will be any rows left undefined. SLH, BGA Breakout & Escapes, Feb 2011

9. BGA Breakout & Escapes • Set the dialog as shown and just mouse sweep the upper left corner of the chip. This is your first what-if scenario. • Typical courtyard pattern SLH, BGA Breakout & Escapes, Feb 2011

10. BGA Breakout & Escapes • From here we’ll work the dialog incrementally. • Select ‘undo’ and change the dialog as shown. • We have now specified Region ‘1’ as our first 4 rows. We have further specified via-pad spacing as ‘0’. SLH, BGA Breakout & Escapes, Feb 2011

11. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. • We have now specified Region ‘1’ with an additional buried and opposite span 2:3 which as specified in setup parameters is coincident with the 1:2 via SLH, BGA Breakout & Escapes, Feb 2011

12. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. • We have now specified Region ‘1’ with an additional buried and opposite span 3:4 which as specified in setup parameters is PE to PE with the 1:2 and 2:3 vias. • Note the diagonal vias. They follow the rules as specified in this area. SLH, BGA Breakout & Escapes, Feb 2011

13. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. • Add Region ‘2’ with 12 rows. We determine this after review the connectivity of this FPGA. Voltage will be primarily on the remaining rows and columns. • Region ‘2’ will use core vias 3:12 as specified and they will be PE / PE. SLH, BGA Breakout & Escapes, Feb 2011

14. BGA Breakout & Escapes • Note that we have a short in the patterns • Point out the DRC note on the dialog. • After what ifs are complete the • user should place a DRC window • and run batch DRC to look for errors. SLH, BGA Breakout & Escapes, Feb 2011

15. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. • Sweep and create the pattern again. Note the change in the via-via spacing on Region ‘2’. SLH, BGA Breakout & Escapes, Feb 2011

16. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. • Add Region ‘3’ with the same settings as Region ‘2’. This will be a single ‘transition row. This time frame select the entire chip and set the pattern.. SLH, BGA Breakout & Escapes, Feb 2011

17. BGA Breakout & Escapes • Note that Region ‘4’ will be all those rows remaining. We still may wish to define those. At this point we need a closer look at the pattern. • Notice we have shorts. We will need to specify the angle of the breakouts. SLH, BGA Breakout & Escapes, Feb 2011

18. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. Frame select and apply to the first 10 or so rows of the BGA. • Still seeing some shorts. SLH, BGA Breakout & Escapes, Feb 2011

19. BGA Breakout & Escapes • Select ‘undo’ and change the dialog as shown. Try changing the angle a bit more. Frame select and apply. • This pattern looks pretty good. SLH, BGA Breakout & Escapes, Feb 2011

20. BGA Breakout & Escapes • Select ‘undo’ . Re-apply to the entire BGA. • Look closely at the patterns. • The Region ‘2’ patterns look good. • Region ‘3’ is unique in that it allows a 90 degree angle but this is creating issues. • We allowed a thru-hole via in Region ‘4’. We can make some improvements here. SLH, BGA Breakout & Escapes, Feb 2011

21. BGA Breakout & Escapes • Select ‘undo’ . • Change the angle on ‘Region ‘3’ to 90 as shown. • Change the Via / pad distance on Region ‘4’ to 20th. • Apply the new settings. Better results! SLH, BGA Breakout & Escapes, Feb 2011

22. BGA Breakout & Escapes • Finished pattern. • Add DRC Window and run Batch DRC to check for errors. SLH, BGA Breakout & Escapes, Feb 2011

23. BGA Breakout & Escapes – Final Demo Settings for Breakout (Suggested) SLH, BGA Breakout & Escapes, Feb 2011

24. BGA Breakout & Escapes • BGA breakouts are done and we are ready for the auto router or… • We may add BGA escapes using the escape tab on the GUI. • Three escape styles provided. • Pins may be escaped by region • Net filter may be used to handle specific cases. • The rule area around the BGA must be tagged as an ‘Escape Outline’. SLH, BGA Breakout & Escapes, Feb 2011

25. BGA Breakout & Escapes • BGA breakouts are done and we are ready for the auto router or… • We may add BGA escapes using the escape tab on the GUI. • Three escape styles provided. • Pins may be escaped by Region • Net filter may be used to handle specific cases. (exclude unwanted escapes) • The rule area around the BGA must be tagged as an ‘Escape Outline’. • Outline must be highlighted to make the dialog live. SLH, BGA Breakout & Escapes, Feb 2011

26. BGA Breakout & Escapes • NSEW – North South East West • Best for hand routing (no layer bias) SLH, BGA Breakout & Escapes, Feb 2011

27. BGA Breakout & Escapes • Layer Bias – For use in conjunction with the auto router • Best for auto routing (layer bias) • Route Targets provide connection point for the router. SLH, BGA Breakout & Escapes, Feb 2011

28. BGA Breakout & Escapes • Target Mode – Same as layer bias but with attention to where the netlines go. (Will attempt to place the escapes in the direction of the intended route with layer bias in mind). • In this example net filter was used to avoid unwanted voltage nets. SLH, BGA Breakout & Escapes, Feb 2011

29. BGA Breakout & Escapes - Helpful Hints • Consult board manufacturer and be sure you have the correct stackup information. • Screen shot and save your setups for future use. (Schemes not available at this time). • Consider chip connectivity when developing regions. (Where are core vias needed / not needed). • Use editor control ‘net filter’ to handle unusual cases where patterns may be different. (Voltages?) SLH, BGA Breakout & Escapes, Feb 2011