Hi,
Prety good question as a bigner.. When I was in your place (near bout 6-7 year before) even I was thinking in the similar way.
Its very difficult to clearify this thing here becuase you are new in this field, you can come to know by experience that why reading is important. But still Let me try.
You are right that Most of the thing is done by the CAD tools.. But you urself use one thing "MOSTLY".. means there are lots of other things which CAD tools can't do. And the worst part is that as a designer you dnt know what rest you have to do yourself.So you should know every thing about the VLSI to solve that thing.
Another thing.. as we know that not a single tool(software ) is 100% error free, there are lots of bugs and lots of area of improvement. But in the chip designing you can't take a risk of even 1%. Because if it will happen then may be the Chip fitted in your laptop/mobile suddenly stop working and then you will complaint to the provider. So every design company have their internal test case to verigy the CAD tools and the team who is developing those test case should have understanding of every thing. Not only basic but they should be updated for this.
Similar things happen in the development center of CAD tools. If they dnt know about the VLSI properly then how will they develop those tools.
For designer team perspective... Some time because of some special specification/non avaliablity of any feature in the CAD tool , they have to debug a lot of things in the design and find out the root cause of problem and then has to solve them. For that they should have sound knowledge of VLSI.
So in short , I can say that 90% of the design can be done by CAD tools, but for a chip this 90% is not that important but rest 10% is important. So you wana be a VLSI engg then remember that you will work in the 10% of design , rest 90% anyone can do it.
nad that's the reason you can see a lot of Computer Science student in VLSI domain, but those are in the CAD tool development not in the design side of Chip. (exception is every where).
Hope this will clerify your doubt.
Keep posted your question .....
Thanks-
Birdy-
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