Important Topics

1.Lambda-based design rules?

Ans. Layout or Design Rules: Two approaches to describing design rules: Lambda-based rules: Allow first order scaling by linearizing the resolution of the complete wafer implementation. To move a design from 4 micron to 2 micron, simply reduce the value of lambda. Worked well for 4 micron processes down to 1.2-micron processes.

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MOST IMPORTANT QUESTIONS FOR INTERVIEW

Q 1: What are the goals of Synthesis Q 2: What are the Tech inputs in PNR Q 3: What are the Design inputs in PNR Q 4: What are the types of cells in PNR Q 5: What are the types of IO pads Q 6: What is the purpose of IO pads Q 7: What is the use of Bound pad Q 8: How tool differentiate the stdcell, IOpad and Macro Q 9: What is difference between soft and hard macro Q 10: How tool calculate the rectilinear blocks area Q 11: Can we rotated the Macro in 90 or 270 degrees Q 12: Assume you have three types of block 7, 9, 12 Metal layers in 28 nm Technology which having more performance and why 13: Which inputs files having resistance and capacitance values Q 14: We have different RC corners im i right, why we have different RC corners Q 15: How multi cut via increase the performance and yeild. Q 16: In which stage normal flop converted into scan flop Q 17: what is difference between normal flop and scan flop Q 18: what is scan chain where we are ...

Double patterning ?

Double patterning in VLSI: Multi patterning also called double patterning ,double patterning is introduced 32nm and lowers layers 10nm,7nm etc. Lithography pattern is a class of technologies for manufacturing IC's,developing for photolithography to enhance the feature of density and Optical microlithography (photolithography) is used for transferring the circuit patterns into silicon wafer. We are use illuminator uv light to shine light through this mask producing an image of the pattern through the lens system ,which eventually projected down into a photo resist coated silicon wafer using a protection system. Double patterning is a technique that decomposes a single layout into two masks in order to increase pitch size and improve depth of focus. Their resolution capabilities have fallen further and further behind the target minimum feature size per each advanced node...

QUESTION&ANSWERS

Q 1: What are the goals of Synthesis ? There are Mainly three goals of synthesis without changing the functionality Reduce the area (chip cost reduce) Increase performance Reduce the power Q 2: What are the Tech dependent inputs in PNR There are three main tech depended inputs Physical libraries -->format is .lef --->given by vendors Technology file -->format is .tf --->given by fabrication peoples TLU+ file -->format is .TLUP-->given by fabrication people Q 3: What are the Design dependent inputs in PNR There are six main design depended inputs Logical libraries --> format is .lib --->given by Vendors Netlist ...

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