Why are CPUs flat

[Beat_my_Laptop]

That's the whole question.

Every cpu I've handled has been vaguely the same thickness, very slim, when the Threadripper needs more power it builds out rather than up or say in a pyramid. Why is this? Is this one of those things that could change with additive manufacturing techniques advancing? I understand thermodynamics enough to know a shape with high & low points would have more variance in reps across it's surface because of convection & so forth, but couldn't that be used to the advantage of the cpu as well?

Is there a real good reason my cpu can't be shaped like a cylinder, a pyramid, or hell even a cube would be cool to see amongst a sea of low profile rectangles

[Guest]

8 minutes ago, Beat_my_Laptop said:

That's the whole question.

Every cpu I've handled has been vaguely the same thickness, very slim, when the Threadripper needs more power it builds out rather than up or say in a pyramid. Why is this? Is this one of those things that could change with additive manufacturing techniques advancing? I understand thermodynamics enough to know a shape with high & low points would have more variance in reps across it's surface because of convection & so forth, but couldn't that be used to the advantage of the cpu as well?

Is there a real good reason my cpu can't be shaped like a cylinder, a pyramid, or hell even a cube would be cool to see amongst a sea of low profile rectangles

just impractical... the die is meant to be CLOSE to the cooler, not 3 inches away on the tip if the pyramid.

Also harder to manufacture, it would need more material.

[Vishera]

24 minutes ago, Beat_my_Laptop said:

That's the whole question.

Every cpu I've handled has been vaguely the same thickness, very slim, when the Threadripper needs more power it builds out rather than up or say in a pyramid. Why is this? Is this one of those things that could change with additive manufacturing techniques advancing? I understand thermodynamics enough to know a shape with high & low points would have more variance in reps across it's surface because of convection & so forth, but couldn't that be used to the advantage of the cpu as well?

Is there a real good reason my cpu can't be shaped like a cylinder, a pyramid, or hell even a cube would be cool to see amongst a sea of low profile rectangles

1.The longer the path the slower it will be,and the path from the top of a pyramid to the bottom is way longer than just using a flat square.

2.Pyramids require a lot of layers that add unnecessary complexity.

3.Silicon is fragile and in a pyramid configuration it will easily break (Glass is mostly made of silicon and quartz!)

4.How do you cool such a pyramid?,what kind of heatsinks will need to be especially developed for it?

5.Lower yields - bigger chips have higher chances of a defect,especially in silicon with a pyramid shape.

[PineyCreek]

Sure, maybe one day we'll have a prism-shaped CPU cluster with a mesh setup 'cause we couldn't create enough interconnects via stacking or due to a limited allowed surface area.  Maybe a biological-based central nexus surrounded by more normal CPUs or quantum CPUs...but it's mostly the realm of sci-fi at the moment.

[rockyroller]

Currently it is flat to allow

1) simple effective external cooling methods to cover the whole die not just parts of it

2) simple method of manufacturing, keeping costs down too

 

In the future this might change but I doubt it for reasons of cost to the consumer

For a SCI Fi instance: a Quantum linked die that doesn't need its parts to be close or even on the same planet to function as a whole.