Chip Design/Architecture Questions

[thorin]

1) I'd always assumed this but things I've heard recently made me wonder. Are CPUs (just the 0.Xum cores .... not including the pin area) multi-layer like motherboard PCBs are? (I'm assuming that if they are then the # of layers basically depends on crosstalk and heat disipation?)

2) Why don't companies mix manufacturing processes. ie: Why doesn't Intel make a processor based on 0.18um tech and it's cache based on 0.13um tech (since the cache is simpler and that would save on space/heat)?

3) It seems there are 'standard' steppings for die size. 0.25 > 0.18 > 0.13 > 0.09um etc.... What motivates some companies to do half steps like 0.15um? Is it a technology/architectural choice or simply marketing/bragging rights?

4) Does Intel (or AMD or whoever) make any of their older chips on their newer processes? ie: Can I find a 0.18um P MMX? I know this seems silly but that would allow for some kewl embedded/shrunk devices.

Thorin

 

[CTho9305]

1) yup. you have one layer of transistors at the very bottom, then 6 layers (in the p4) of "interconnects" (wiring), as the core, which is then put in the packaging which has the pins.

2) the size of parts varies. some features are as small as .13, but others are bigger on the same chip. i'll see if I can find a pic

3) they probably cannot get .13 working but can get .15

4) dunno

 

[CTho9305]

check out pages 8 and 9 of this:
linky
note how there are different sized interconnects. on page 8, the interconnects are coming out of the page, and the vertical one is a cross-layer connection

(thx to wingznut for the link and a LONG explanation of it all )

btw, about the left pic on page 8... i think that is aluminum vs. copper on the right side. I think the lighter-colored vertical pieces are tungsten and the interconnects are aluminum, but I dont remember why or who told me.