The self-assembling computer chips of the future | Karl Skjonnemand

Computers used to be as big as a room.

But now they fit in your pocket,

on your wrist

and can even be implanted inside of your body.

How cool is that?

And this has been enabled by the miniaturization of transistors,

which are the tiny switches in the circuits

at the heart of our computers.

And it's been achieved through decades of development

and breakthroughs in science and engineering

and of billions of dollars of investment.

But it's given us vast amounts of computing,

huge amounts of memory

and the digital revolution that we all experience and enjoy today.

But the bad news is,

we're about to hit a digital roadblock,

as the rate of miniaturization of transistors is slowing down.

And this is happening at exactly the same time

as our innovation in software is continuing relentlessly

with artificial intelligence and big data.

And our devices regularly perform facial recognition or augment our reality

or even drive cars down our treacherous, chaotic roads.

It's amazing.

But if we don't keep up with the appetite of our software,

we could reach a point in the development of our technology

where the things that we could do with software could, in fact, be limited

by our hardware.

We've all experienced the frustration of an old smartphone or tablet

grinding slowly to a halt over time

under the ever-increasing weight of software updates and new features.

And it worked just fine when we bought it not so long ago.

But the hungry software engineers have eaten up all the hardware capacity

over time.

The semiconductor industry is very well aware of this

and is working on all sorts of creative solutions,

such as going beyond transistors to quantum computing

or even working with transistors in alternative architectures

such as neural networks

to make more robust and efficient circuits.

But these approaches will take quite some time,

and we're really looking for a much more immediate solution to this problem.

The reason why the rate of miniaturization of transistors is slowing down

is due to the ever-increasing complexity of the manufacturing process.

The transistor used to be a big, bulky device,

until the invent of the integrated circuit

based on pure crystalline silicon wafers.

And after 50 years of continuous development,

we can now achieve transistor features dimensions

down to 10 nanometers.

You can fit more than a billion transistors

in a single square millimeter of silicon.

And to put this into perspective:

a human hair is 100 microns across.

A red blood cell, which is essentially invisible,

is eight microns across,

and you can place 12 across the width of a human hair.

But a transistor, in comparison, is much smaller,

at a tiny fraction of a micron across.

You could place more than 260 transistors

across a single red blood cell

or more than 3,000 across the width of a human hair.

It really is incredible nanotechnology in your pocket right now.

And besides the obvious benefit

of being able to place more, smaller transistors on a chip,

smaller transistors are faster switches,

and smaller transistors are also more efficient switches.

So this combination has given us

lower cost, higher performance and higher efficiency electronics

that we all enjoy today.

To manufacture these integrated circuits,

the transistors are built up layer by layer,

on a pure crystalline silicon wafer.

And in an oversimplified sense,

every tiny feature of the circuit is projected

onto the surface of the silicon wafer

and recorded in a light-sensitive material

and then etched through the light-sensitive material

to leave the pattern in the underlying layers.

And this process has been dramatically improved over the years

to give the electronics performance we have today.

But as the transistor features get smaller and smaller,

we're really approaching the physical limitations

of this manufacturing technique.

The latest systems for doing this patterning

have become so complex

that they reportedly cost more than 100 million dollars each.

And semiconductor factories contain dozens of these machines.

So people are seriously questioning: Is this approach long-term viable?

But we believe we can do this chip manufacturing

in a totally different and much more cost-effective way

using molecular engineering and mimicking nature

down at the nanoscale dimensions of our transistors.

As I said, the conventional manufacturing takes every tiny feature of the circuit

and projects it onto the silicon.

But if you look at the structure of an integrated circuit,

the transistor arrays,

many of the features are repeated millions of times.

It's a highly periodic structure.

So we want to take advantage of this periodicity

in our alternative manufacturing technique.

We want to use self-assembling materials

to naturally form the periodic structures

that we need for our transistors.

We do this with the materials,

then the materials do the hard work of the fine patterning,

rather than pushing the projection technology to its limits and beyond.

Self-assembly is seen in nature in many different places,

from lipid membranes to cell structures,

so we do know it can be a robust solution.

If it's good enough for nature, it should be good enough for us.

So we want to take this naturally occurring, robust self-assembly

and use it for the manufacturing of our semiconductor technology.

One type of self-assemble material --

it's called a block co-polymer --

consists of two polymer chains just a few tens of nanometers in length.

But these chains hate each other.

They repel each other,

very much like oil and water or my teenage son and daughter.

(Laughter)

But we cruelly bond them together,

creating an inbuilt frustration in the system,

as they try to separate from each other.

And in the bulk material, there are billions of these,

and the similar components try to stick together,

and the opposing components try to separate from each other

at the same time.

And this has a built-in frustration, a tension in the system.

So it moves around, it squirms until a shape is formed.

And the natural self-assembled shape that is formed is nanoscale,

it's regular, it's periodic, and it's long range,

which is exactly what we need for our transistor arrays.

So we can use molecular engineering

to design different shapes of different sizes

and of different periodicities.

So for example, if we take a symmetrical molecule,

where the two polymer chains are similar length,

the natural self-assembled structure that is formed

is a long, meandering line,

very much like a fingerprint.

And the width of the fingerprint lines

and the distance between them

is determined by the lengths of our polymer chains

but also the level of built-in frustration in the system.

And we can even create more elaborate structures

if we use unsymmetrical molecules,

where one polymer chain is significantly shorter than the other.

And the self-assembled structure that forms in this case

is with the shorter chains forming a tight ball in the middle,

and it's surrounded by the longer, opposing polymer chains,

forming a natural cylinder.

And the size of this cylinder

and the distance between the cylinders, the periodicity,

is again determined by how long we make the polymer chains

and the level of built-in frustration.

So in other words, we're using molecular engineering

to self-assemble nanoscale structures

that can be lines or cylinders the size and periodicity of our design.

We're using chemistry, chemical engineering,

to manufacture the nanoscale features that we need for our transistors.

But the ability to self-assemble these structures

only takes us half of the way,

because we still need to position these structures

where we want the transistors in the integrated circuit.

But we can do this relatively easily

using wide guide structures that pin down the self-assembled structures,

anchoring them in place

and forcing the rest of the self-assembled structures

to lie parallel,

aligned with our guide structure.

For example, if we want to make a fine, 40-nanometer line,

which is very difficult to manufacture with conventional projection technology,

we can manufacture a 120-nanometer guide structure

with normal projection technology,

and this structure will align three of the 40-nanometer lines in between.

So the materials are doing the most difficult fine patterning.

And we call this whole approach "directed self-assembly."

The challenge with directed self-assembly

is that the whole system needs to align almost perfectly,

because any tiny defect in the structure could cause a transistor failure.

And because there are billions of transistors in our circuit,

we need an almost molecularly perfect system.

But we're going to extraordinary measures

to achieve this,

from the cleanliness of our chemistry

to the careful processing of these materials

in the semiconductor factory

to remove even the smallest nanoscopic defects.

So directed self-assembly is an exciting new disruptive technology,

but it is still in the development stage.

But we're growing in confidence that we could, in fact, introduce it

to the semiconductor industry

as a revolutionary new manufacturing process

in just the next few years.

And if we can do this, if we're successful,

we'll be able to continue

with the cost-effective miniaturization of transistors,

continue with the spectacular expansion of computing

and the digital revolution.

And what's more, this could even be the dawn of a new era

of molecular manufacturing.

How cool is that?

Thank you.

(Applause)