By: anonymouse (anony.delete@this.mouse.com), June 24, 2022 3:47 pm
Room: Moderated Discussions
Doug S (foo.delete@this.bar.bar) on June 24, 2022 1:31 pm wrote:
> Why are wafers round? Since we make chips that are square or rectangular, making
> wafers square would minimize or totally avoid wasted silicon on the edges.
>
> I mean, I know that the first order is: they are round because all
> the equipment is designed to handle round wafers not square ones.
>
> But was any thought ever given to switching to square wafers when iterating from 100mm to 150mm to
> 200mm and 300mm wafers? Or is there some obvious reason why they must be round that I'm missing?
How many die designs would fit nice and neatly exactly into a square wafer anyhow? Unless you compromise your design to fit dimensionally, you will still end up having a number of partial die on the square wafer regardless.
> Why are wafers round? Since we make chips that are square or rectangular, making
> wafers square would minimize or totally avoid wasted silicon on the edges.
>
> I mean, I know that the first order is: they are round because all
> the equipment is designed to handle round wafers not square ones.
>
> But was any thought ever given to switching to square wafers when iterating from 100mm to 150mm to
> 200mm and 300mm wafers? Or is there some obvious reason why they must be round that I'm missing?
How many die designs would fit nice and neatly exactly into a square wafer anyhow? Unless you compromise your design to fit dimensionally, you will still end up having a number of partial die on the square wafer regardless.