I'm not a native speaker, but I tried: Создание микропроцессора занимает месяцы и включает в себя более 250 этапов производства, но на их разработку могут уйти годы.

Lydie, just wow, if you aren't a native speaker.

A few vocabulary notes (though notiing in your word choice gives away a speaker fo a different langauge):

создание is 'creation, creating' also one of words for 'creature'. An elevated word compared to 'изготовление', usually not about shoes. Used when изготовление won't work (e.g. in "creating a space"), with immaterial things, with unique achievements and art or as a more elevated word for anything.
In the latter qualiity it can be applied to a shoe, but it implies that it is unique, that it is art. Usually it includes designing.

изготовление (making, manufacturing... literally "preparing-from") works both for hand made items and factory mass production.

производство ('production', a calque from Latin), directly points at mass production and industry. Stone Age industry maybe, but still:)

A verbal noun делание is a bit awkward and used only where it's really needed (philosophy, religion, linguistical glosses - usually for 'doing'). If you want to use 'делать' you should bypass this with 'на то, чтобы сделать .... нужны месяцы' ('то' substitutes a noun, the rest clarifies то).

My choice is изготовление, it creates the contrast between making and designing.
Unlike производство it works well for a single item and doesn't create tautology.

Exactly!  Thank you! 

Чтобы создать микропроцессор и запустить технологический процесс уйдёт около месяца, но и чтобы их разработать может занять около года