Learn English like this without translation.
Do not write any of your language translation, as your brain will be fooled in storing it as a synonym in your language.
As in context
Demand for - increase in need for the semiconductors by car makers.
Step up - increase production of semiconductors by car makers
Here it means, to increase dramatically.
A return to normal after a difficult situation.
Fill their need
Here car makers need to be provided with what they need badly.