Analog Layout 2 years Experienced - Green Semi

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 Why matching? Types of Matching? How do we decide which matching for specific device?

  • To overcome error due to Process variation, Ion Implantation….

  • To minimize variation in x & y axis we go for Cross Coupled Common Centroid, Interdigitized, Common Centroid based on our requirements.

  • Diff pair we go for Cross coupled Common Centroid.->> For Amplifier it is Voltage dependent, by controlling Vgs we can control its ON & OFF operation and hence current. Hence Voltage places a crucial role than Current for Current Mirror->> hence matching of Differential Amplifier is very very important.

On what factors we consider whether to go for matching or not. As there are additional disadvantages of Matching.

  • Speed->>Parasitic cap will be added.

  • We need to minimize cap

Why we always shield to Ground and not VDD?

  • There are more variation in VDD as there may be two voltages 3.3V or 1.8V but little variation in ground because of noise hence we always go to Ground.

What are STI, LOD, WPE related to Matching?

What is Latch Up? Prevention for Latch up?

What is Electro migration? How do we verify EM, IR (device/tool?)

What is ESD related to Latch Up?

Explain Antenna effect. How do we protect? How jumper prevents this antenna effect? (Apart from planarization)

How do we minimize IR issue if we can’t switch for higher metals as in Standard cell when all are fixed?

Avoid unnecessary jogs try to make it straight. Try to reduce Resistance.

Which tool is best among all Verification Tools? What’s Gemini tool used for?

What is EMIR Analysis? Using silicon frontline R3D

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