some interesting interview questions on physical design

• What are physical design flows, various activities you are involved?
  
• Design complexity, capacity, frequency, process technologies, block size you handled.
  
• Why power stripes routed in the top metal layers?
  The resistivity of top metal layers are less and hence less IR drop is seen in power distribution network. If power stripes are routed in lower metal layers this will use good amount of lower routing resources and therefore it can create routing congestion.
  
• Why do you use alternate routing approach HVH/VHV (Horizontal-Vertical-Horizontal/ Vertical-Horizontal-Vertical)?
  This approach allows routability of the design and better usage of routing resources.
  
• What are various techniques to resolve congestion/noise?
  Routing and placement congestion all depend upon the connectivity in the netlist , a better floor plan can reduce the congestion.
  
• How do you optimize skew/insertion delays in CTS (Clock Tree Synthesis)?
  Better skew targets and insertion delay values provided while building the clocks.
  
  Choose appropriate tree structure – either based on clock buffers or clock inverters or mix of clock buffers or clock inverters.
  
  For multi clock domain, group the clocks while building the clock tree so that skew is balanced across the clocks. (Inter clock skew analysis).
  

HERE is the full list of the questions. Include above selected physical design interview questions.

ANOTHER LIST of interview questions.