What is Moore’s Law?
Gordon E Moore is an American engineer and co-founder of Intel Corporation, alongside Robert Noyce. Born January 3rd 1929 in California, Moore achieved a PhD in Chemistry and Physics from the California Institute of Technology. He went on to work at Shockley Semi-conductor Laboratory researching manufacturing methods for silicon based transistors (William Shockley was part of the team that won a Nobel Prize for inventing the transistor) before eventually Co-founding Intel Corporation in 1968 with his friend Robert Noyce. Despite his rich history, Moore is best known for his statement made in a special issue of the weekly trade journal ‘Electronics’ on April 19, 1965. The statement read,
“The complexity for minimum component costs has increased at a rate of roughly a factor of two per year… Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built on a single wafer.”
Moore never labelled it as a law and never set out to create a law. In 1975 Moore revised his prediction, changing his time frame to 2 years as the rate of increase in components had decelerated. As time would tell, the number of components would inevitably double approximately every 18 months. It is important to note that even with this huge increase in components used, there was no increase in power consumption.
Modern day integrated circuits have millions, some even billions of components on them, all created from a single piece of silicon. The number of transistors on an integrated circuit is known as the ‘transistor count’; the largest transistor count in a commercially available microprocessor is 39.54 billion. If you look at the graph below, you can see that Moore’s law has held true with the number of components on a silicon chip doubling approximately every two years. This trend has continued now for longer than 50 years, much longer than Moore himself first predicted.
In a recent interview with Rachel Courtland from IEEE Spectrum, Moore spoke of the physical limitations that could bring the end of Moore’s Law; the atomic scale, the speed of light.
Contrary to Moore’s Law, the rate of progress in the development of Microprocessors has decreased industry-wide since 2010. Brian Krzanich, the former CEO of Intel, announced, “Our cadence today is closer to two and a half years than two.” You can find the steps involved in making a CPU (Central Processing Unit) at the bottom of this article.
The Future of Computing
It has come to a point where manufacturers need to start changing the way they think about building computers. A classical computer uses a sequence of bits (values of 0 and 1) representing two states to make sense of and make decisions about the data they input following a prearranged set of instructions. Classical computers are unlikely to be replaced, however Quantum Computers are expected to help solve complex problems that currently surpass the capabilities of a classical computer.
In the race for Quantum Supremacy, Google recently announced that they managed to perform a random sampling calculation on their Google Sycamore device in just 200 seconds. Google claim that this same calculation would take the world’s most powerful supercomputer, IBM’s Summit machine, as long as 10,000 years to complete. IBM have since hit back at this claim and state that their Summit machine would complete the calculation in 2 and a half days; even if IBM’s claim is correct, this still demonstrates how impressive quantum computing can be.
Quantum computers are not ready to face real world tasks yet, that feat could be decades away. However, Gilligan-Lee of University College London says, “it is the first baby step on a long road to getting useful quantum computers.” Read more about Google’s progress in Quantum Computing.
It is an exciting time in the technology world, researchers believe that when we crack quantum computing we will be able to invent new molecules for use in medicine along with simulating and controlling more complex molecules that we are currently unable to. With the slow down of Moore’s Law, the foreseeable future may come down to software developments in the race for more computer power as we wait for the era of quantum computing.
The process of making a CPU
1. CPU’s initially start out as sand.
Silica sand contains a high amount of silicon dioxide which is the base ingredient of semiconductor manufacturing.
2. Silicon is then separated from the raw sand & purified to reach manufacturing quality known as ‘electronic grade silicon’.
A mono-crystal is produced weighing in at 100kg and 99.9999% silicon purity. This crystal is then sliced into discs known as wafers & polished until they have flawless, mirror-like surfaces.
3. A photo-resist coating is applied to the silicon wafer, similar to those used in film for photography. In this step the wafer is spun to apply the coating as evenly as possible.
4. The now photo-resistant finish is exposed to UV light. This process causes a chemical reaction, creating a print on the wafer.
The UV light focal point is reduced to a small focal point by a lens, resulting in the print on the wafer being 4x smaller than the masks pattern. This is similar to the process of film being printed onto film reel inside a camera.
5. A chemical solvent is then used to dissolve the soluble photo resist material before another chemical is used to partially dissolve away a tiny quantity of the substrate (polished semiconductor material).
The etched surface or the wafer is then revealed by removing the remainder of the photo resist material through a similar process.
6. The tiny copper wires on CPU’s are what convey electricity to and from the chips various connectors. They are created through adding additional photo resists, exposing and washing.
The outcome is a chip that looks like a children’s climbing frame, a host of tiny copper bars, some connected, some a very specific distance away from other ones. This multi-layered process is repeated all over the wafer in location where chips can be made.
7. Now all the different layers have been built up on our wafer and the transistors are all created, it is time to test the CPUs. To do this, we simulate how the chip would operate when packaged into end-consumer products.
However, the chips perform is kept in a database assigned specifically for that die.
8. A diamond tipped saw is then used to slice the silicon wafer into its various dies. The information recorded in step 7 is used to determine which chips are kept and which are discarded.
The chips are then packaged and labelled based on the performance data captured in the testing process.