Qualcomm Interview Question (Physical Design)

Qualcomm Interview Question (Physical Design Engg) 

1. Practical flow of the design?

2. How analog macro is placed?

3. Explain the power plan structure in your design?

4. What is the routing blockage for analog macro?

5. What are the checks after the floorplan?

6. What are the steps in the placement stage?

7. What is the block size, utilization, target skew, WNS of your design?

8. What are the corners in your design?

9. What are the corners considered in the placement stage? why?

10. What are the corners considered in the CTS stage? why?

11. What are the causes for congestion. And how to fix it?

12. What could be the reason for congestion, if there is neither cell density nor pin density and

also, there is no much communication between nearest macro and std cells as well?

13. How to fix setup and hold issues?

14. Give the order of priority among various setup fixing methods? And reasons for them?

15. How tran Violation will affect the setup?

16. In case, there are 10000 setup violations in the placement stage, what could be the issue?

17. What kind of constraint will lead to so many setup violations in the placement stage?

18. How to analyze timing reports. And how the approach will be for fixing slack?

19. If there are many shorts at one place in the routing stage, what could be the possible reason?

20. What are the checks after CTS?

21. Why we check hold after CTS?

22. What are the checks after routing?

23. What are the different kinds of DRC checks?

24. In case there are many shorts, opens, setup, hold violations...what you will address first?

25. What are tap cells? How much distance given in your design and why?

26. What is the use of tap cell?

27. If we don’t use tap cells, what error we will get?

28. What are low power techniques?

29. Explain isolation cell, retentions cell, power switches, and level shifters.

30. How to fix static and dynamic IR issues.

31. Assume there are 6 timing corners, if the hold is not able to fix in one corner, how to fix it without

affecting the other corners. What is the better approach to fix it without affecting others?

32. Write few commands from ICC2, INNOVUS?