Quaz51 said:
Panajev2001a said:
Everything else except area of the chip staying equal going from 200 mm Wafers to 300 mm Wafers we could in theory have 1.5x bigger CPUs compared to the 180 nm EE.
224 * 1.5 = 336.
it's 1.5*1.5 > 2.25x bigger surface
Of course... duh.... dumb me who just divided 300 by 200, I forgot that I was dividing diameters and not surfaces
(221,841 (mm^2)) / (98,596 (mm^2)) = 2.25
I do not think that your correction worsen my argument though
224 mm^2 * 2.25 = 504 mm^2
A 290-300 mm^2 chip would only be 55.5-59.5% of the theretical increase they could get and seems feasible taking into account complications which might occur at a chip size of this magnitude.
If we take a 300 mm^2 chip and 300 mm Wafers we could make ( if the Wafer had a rectangular shape ) around 739 chips... Let's say 600 to take a bit into account the fact the Wafer is circular and we do not use the surface very well ( I am making the case for approximately 139 * 300 mm^2 of Wafer's surface not to be utilizable ).
If we take the 180 nm EE measuring 224 mm^2 ( which is not asking you to start counting transistor density [btw, the official Kutaragi's PDFs state 10.5 MTransistors not 13 MTransistors] ) and 200 mm Wafers we could make around 440 chips ( if the Wafer had a rectangular shape ).
Let's only trim it to 400 chips to skew the comparison a little in favor of the 200 mm Wafer.
This is still giving us 200 more chips produced with the 300 mm Wafers and the chip size increased to 300 mm^2.
Even if shit happens and the yelds drop badly to only 405 chips ( yelds = 65% ) while assuming all 400 chips manufactured on the 200 mm Wafers ( 224 mm^2 chips ) are working up to specs ( again we are trying to skew the comparison against the 300 mm Wafers and 300 mm^2 chips argument ), this is still good news.
If we say let'sd be more negative, I would say well let's at least assume the 224 mm^2 chips on 200 mm Wafers will have yelds around 70% ( the 180 nm process is not at its peak [think year 1999] ) which means about 280 chips.
Let's say that on the 300 mm Wafers the 300 mm^2 chips we only get 282 chips working out of 600.
This means yelds around 47% and while this in itself is low, all things considered we still get the same number of chips + 2 as what we did on 200 mm Wafers and 224 mm^2 chips.