Depth Processing Chips and Circuit Boards

Welcome to Flatland! 
(Reference to Edwin A Abbott's book: Flatland... strangely appropriate in this case.)


A strange question tickled my mind when I was looking online for computer upgrades...
       
..Why are all Chips and Circuit Boards only manufactured in two dimensions?

If you look at images of chips, chip sets, and computer circuitry, you will see what I mean.  They are all printed on flat materials and the chips themselves are flat, rectangular objects affixed to them.

Surely this is not very efficient in terms of processing ability and power consumption.

Of course, it is evident that when the first chips and boards were made, it was for ease and efficiency of manufacture that simply stamping out these items made computers an economically viable product, and so helped create the industry we see today.... not to mention the technology available at that time being only able make them in this way.
         But surely technology has evolved since that time enough for manufacturers to be able to address this inefficiency (in most part, due to this stage of technological development making newer technology possible)... or is it just a case of technological myopia-an oversight of those gifted minds who create these chips, so focused on how to cram the most ability into the standard circuit board format that they just haven't considered that the format itself must change in order to gain those extra margins of improvement in performance.

Rather than a flat chip, of say, 2cm by 4cm, wouldn't you be able to get more in to it if you added volume, to this processing area?  Perhaps a 1cm cube?

If a particular function of the chip in flat chips (and by extension, the boards) must transmit a signal from point A in a chip to point B along the length of this chip... then this can be anything up to 4cm distance that signal has to travel to reach this point in the flat chip dimensions described...
     ....but in a cube chip, has can contain all the necessary parts of the flat chip, but more efficiently arranged, any distance is necessariy shorter.

The shorter distance means greater speed, or that the same speed conveys the signal in half the time, which means less power required to perform the same operation, and this effect is enhanced due to less of that power being lost in heat, and further, whatever signal degredation occurs in the transmission does not require extra power to compensate.

Other than in phone or tablet technology, in which it is desirable to have flatness, wouldn't it be better to have such cubes (croutons?) arranged in three dimensional lattice boards or grid blocks in computers such as mainframes and internet servers?


Consider this example:

If I am in an office block, on the 2nd florr say, and I want to go to the same floor plan location directly above me on the 3rd floor, I have to walk all the way to the lift or stairs across the floor I'm on, weaving through any obstacles in my way, like desks and people etc. Go up, and then make a similar journey back across the 3rd floor to this location.
         But if I could just jump straight up through the floor to the point desired when I wanted, it would take less time and energy.

Now of course there are reasons why we can't do this in office blocks, but not so much in computer circuitry.

And also, consider our own brains.... it is said there are more connections between neurons than stars in the galaxy.  But that is not to say that there are more neurons.  And this is because they are arranged relative to each other in three dimensions, allowing for an exponential increase in the possible permutations of functionality of each distinct neuron.  More Bang for the buck, as the saying goes.

Creating computer hardware in this way may eliminate the need for some components altogether because of these new permutations... the chips being able to be used in conjunction with different chips in different ways by turns to produce varying functions, that multitudes of dedicated chips for those specific functions used to perform.

With the advent of three dimensional printing to produce prototype models of designs drawn on computers, surely a cubic (or spherical, being the most efficient shape distance wise) chip can be designed and manufactured layer by layer and slotted into it's position in the circuit block.