An Update on Moore's Law


'An Update on Moore's Law'
Intel Chairman Emeritus Gordon Moore

Intel Developer Forum Keynote September 30, 1997, 8 a.m. San Francisco

Good morning again. I trust yesterday was useful for you, especially considering that we have two more days of it. This morning, we have Gordon Moore to come speak with us, and I've had a lot of questions in the last couple years about how did he come up with this thing called Moore's Law? And I happen to be privy to the insight of how this really happened. You see, Gordon is a deep sea fisherman, he loves to go fishing, and early back in 1965 or so, he was out fishing one day, and he was musing on the fact that he had noticed over the last year or so that he was actually able to get a couple more transistors on that die. And he thought, 'Hmm, I wonder how often these things are actually going to double in terms of the number of transistors I can get on the chip.'

And he thought, 'I know; however many fish I catch today; that's how many years it's going to be.' He got 18 fish; it was 18 months. Without further ado, let's bring on Gordon Moore.


DR. GORDON MOORE: Well, good morning. It's a pleasure to be here, even at this time in the morning.


DR. GORDON MOORE: What I'm going to do today is talk a bit about the semiconductor technology that underlies the products that we've all grown to love, hate, or whatever the proper emotion is, depending on how well they're working. I want to try to convey some of the perspective on the semiconductor technology by looking historically at some of the things that have happened and making some projections of where it might go from here.

It really is the driving technology for a bunch of the progress in electronics. Let me look at the semiconductor industry from a couple of points of view. First, the natural one of looking at what has happened financially. You know, this is a growth industry by almost anyone's measure. It is outbound annual growth rate over this 20-year period -- excuse me, 30-year period is about 20 percent. And it hasn't been completely smooth. You see a couple of peaks there. For example, a peak in 1984 followed by the dip in 1985.

They don't look much plotted on the semi-log paper like this, but going through them, it seems an awful lot more traumatic.


DR. GORDON MOORE: In fact, that particular peak-to-valley cost Intel a third of its work force, looking back on it.

While this is a phenomenal record of growth, I look at the number of transistors shipped every year and that's what's interesting to me. {} In the early days, and I first started doing this in the 1970s, I had to take the industry reports of all the products shipped and estimate the number of transistors in each of the circuits, and in some of the microcontrollers and go down almost product by product and add them all up, the last several years, all I have to do to get a reasonable estimate of the number of transistors is count the DRAM bits and multiply by two. It really made this job an awful lot easier.

But this is really spectacular. We're up approaching 10 to the 17th transistors per year. 10 to the 17th is a number that we use quite a bit when we're talking about atoms and things like that. When you're talking about something that's manufactured, a transistor, it takes, I think, a few comparisons to try to put it in perspective.

For example, E.O. Wilson, the famous Harvard biologist who is an expert on ants, estimates that there are 10 to the 16th and 10 to the 17th ants on earth. But if you look at this curve, this year we're making one transistor for every ant.


DR. GORDON MOORE: Next year it will be 1.8 transistors per ant since the average growth over here is about 18 percent per year compounded over a 30-year period. In fact, for a period in the ?0s when this curve is a little steeper, we were actually going up an order of magnitude about every three years. Tenfold in three years is obviously more than doubling every year.

So every year we were building more electronics than existed in the world on January 1st of that particular year. That is really a growth industry.

Now, you can take these two curves and divide one by the other and you see really one of the driving forces. The average price of the transistor over this time period has dropped almost six orders of magnitude, down to the point where it's only a few micro-bucks today.

To me, this is the key thing that has happened. It's something that is really unprecedented in any manufactured item I could find, that this kind of cost reduction can occur.

And of course it's the reason that electronics have become so cheap that they can be used in a wide variety of applications today that we couldn't even have considered at the time this curve was initially done.

You might ask how can this happen? How can a technology reduce costs this much, and how can this huge increase of the number of transistors used occur. And it takes a couple of things. First of all, it takes a phenomenally elastic market; something that can swallow ten to the eighth times as many transistors over a few decades by the development of new applications, and people figuring out how to use those transistors. And secondly, it takes a unique technology. And I think we have both here. Clearly, the market elasticity was demonstrated by the increase in the number of transistors.

The reason is we have a violation of Murphy's Law that we're exploiting with the technology. By making things smaller, everything gets better simultaneously. We don't even really make a tradeoff. The transistors get faster, the electrons don't have so far to go, the capacitance goes down and one thing and another. Shorter interconnections again speed up the operation of electronics and decrease the power necessary to drive the interconnections. System reliability is increased tremendously because we put a lot more of the system on the chip, which is a controlled environment. And another interesting thing, that over this whole history of the industry, from the single transistors to the devices we've made today, the reliability per packaged semiconductor device, being a 64 megabit DRAM or a single transistor, has remained about constant. So the system reliability has grown tremendously as we've put more and more electronics on a given chip.

We can decrease the power; again, because we get things closer together, make them smaller. But the thing that really drives the industry, in my view, is the fact that we can make things cheaper by putting them on chip.

Now, this has a lot of consequences. What we end up doing is really selling real estate. We've sold area on the silicon wafer for about a billion dollars an acre, that order of magnitude, as long as I've been in the industry. Individual transistors used to sell for a few billion dollars an acre. The microprocessors today, too. Maybe DRAMs are something under a billion. But the real question, then, in what the electronics sell for is what development density we can live with; if we have to have a single transistor on our expensive real estate or if we can develop a lot of electronics.

So if you look at it in a relatively simple-minded manner, you get a pretty good idea of the economics.

Doesn't change an awful lot. What really counts is how much stuff we can pack on that area.

This results in, you know, some rather dramatic changes in economics. The first planar transistors we sold in about 1959, the year the planar transistor was introduced, sold for several dollars. In fact, the first ones we shipped sold for $1.50, I remember very clearly. But a good transistor in those days sold on the order for $5 or $6. Today, you can buy a 16 megabit DRAM for the same $6. That's something over 16 million transistors with all the interconnections and everything else for the price of a single transistor, something less than 30 years ago. This is really pretty dramatic.

And the way this change in the technology gets applied to something like our family of microprocessors is shown on this slide. And you see, there are really two major trends here. First, if you only look at the left entry in each of these several lines, you see as we move down, the chips get bigger. The area actually increases because we're able to make bigger chips as our manufacturing processes are cleaned up. We get our defect densities down and so forth. We get adequate yields with bigger pieces of silicon.

But if you look at the trends horizontally, each of these generations of processors goes through several generations of semiconductor processing and takes advantage of it. For example, if you look at the Pentium processor line there, you see that that is going through four different generations of technology. A generation of technology typically reduces the minimum feature size by a factor of about .7. So it reduces the area by about .7 squared. So things get smaller, we get more on the wafer. The real estate goes in half. We know what less real estate does to the cost.

But also, we move to a next generation of transistor. The transistors get faster. We can use that additional speed in the decreased area, either to lower the power or to increase the performance or a bit of each.

So a given generation of products, like the Pentium processor, will take advantage of several generations of the processor -- of the process technology to give the lower cost, higher performance, lower power that are important for a variety of the applications.

This is true not only for the processors but it works also for other functions. For example, I looked at some network chips that Intel has made over the years, and as you can see, the early one of these on two micron technology has kind of changed in function but we're going down to the point now where we have full 100 megabit integrated controllers on a single chip, and that will be shrunk to take advantage of the next generation of technology. In fact, it's in the process now.

So there's tremendous leverage by moving generations of technology and by putting things on chip.

This has an interesting impact that if people understand and anticipate, is very powerful. If they try to resist, it can be a problem.

The thing is that this advantage of putting more and more stuff on the chip means that if you really want to take advantage of the semiconductor technology, what you have to do is put more of the system functions on the chip continually. And this has been kind of a hard thing for the semiconductor industry to convince some of the customers of over of the years. I remember the first semiconductors we made at Fairchild in 1961, were integrated circuits we were actually bringing them to the market, and we went to our customers, we were proud of this new achievement, a complete circuit on a chip. I remember going to one aerospace company with our integrated flip-flop circuit and saying, 'Look, we can make a flip-flop for you.'

First, our interface at the customer was a circuit design engineer, and going in to a circuit design engineer and saying, 'Hey, we can do your circuit design for you' doesn't give you the most favorable response. In fact, the response we got from that one was 'We have 16 different flip-flops we need in our system. We have an expert on each one of those.' There were dozens of ways our flip-flop was inferior to any of those and it wouldn't fit any of the applications. Why were we wasting our time doing circuit design.

And then my colleague, Bob Noyce, came up with another one of his major contributions to the semiconductor industry. He said, 'We'll sell you the complete circuit for less than you can buy the individual components to build your own.'

That was the key thing that got them over the hump of, oh, OK, it's cheaper that way. We'll use integrated circuits. And from those very simple circuits it's grown in complexity. We've had to bring more and more and more and more of the stuff onto the chip. And the result is, in technology, it often swallows the customer's added value and gives it back to them free.

The customers that understand that, anticipate it and use it, have been very successful. Those that try to resist it find themselves spending a lot of time and energy and money on things that their competitors don't.

So I view this as the natural direction that technology drives the industry. It's something that you have to accept and try to exploit to move ahead. And it's not really -- the semiconductor manufacturers desire to take all the value added. But, that's nice.


DR. GORDON MOORE: It really is the way that we have to move in we're going to exploit the advantages of the technology today and moving forward.

What happens is with a PC board, one month or one year moves on to a chip not much after that. This showing an interface, an Ethernet interface card, moving from some ten chips to a single chip over a time scale like this.

The other natural consequence of this is that the product complexity continues to increase. And here I show product complexity measured by the number of transistors in the circuits, both for DRAMs, which since you don't waste much space laying out a DRAM, tend to be more complex than the microprocessors, and some of the microprocessors. Actually, the last point of the microprocessors is falling a little below the line. That's not because we can't put more on a chip. It's an economic tradeoff as these chips get fairly large.

The technology that drives that is our ability to make things smaller, this violation of Murphy's law, for as long as we've been exploiting this technology, which I date from about the first planar transistor in 1959, which is for some -- that's almost 40 years now, 38 years, we've been on a trend that cuts the minimum feature size in half about every six years.

We actually do a turn of the technology probably twice that often. So over most of this time, the generations of technology have shrunk by the magic 70 percent or to 70 percent of the previous size about once every three years. And as you see, Intel's technology has followed that curve fairly precisely. Some of the early points are missing, but they were pretty much sprinkled on the blue line. And the semiconductor industry road map was put together a few years back for the leading edge technology, again stays on that factor of .7 in minimum features every three years.

As we get smaller in the X/Y directions it's also important that we shrink the thickness of the films. This shows the insulator thickness in the MOS transistors is a function of the minimum size for various levels of technology.

Frankly, this curve surprises me more than the other one does. The other one is pretty impressive getting down to quarter micron technology now, approaching the wavelength of visible light.

This one, on the other hand, has gone much further than I would have anticipated. I remember in the early days figuring that probably a thousand angstroms was as thin as it would ever be able to go with insulating layers. Back of the envelope kind of calculations.

That took a model of atoms plopping in random on a surface, suggested that if you got many fewer atomic layers and down to a thousand angstroms, the likelihood of a pinhole would be high enough that you wouldn't be able to keep the integrity of the film over a very large area.

That completely neglected the fact that chemical forces are actually working for us here rather than against us. It's not a random dropping of atoms on the surface at all but a very careful build up of a film layer by layer. You can go very much thinner than that. The point furthest on the right there that corresponds to something like 30 angstroms is ten molecular layers thick. And even at that level, we have good integrity of the film. So this can continue to go for a while. I hesitated to extrapolate it beyond the right edge of the curve, but certainly the opportunity to continue moving in that direction exists.

The impact of these technological changes, making things smaller so they go faster, putting more stuff on a chip, gets reflected in the performance of the devices. And this is the performance of Intel's microprocessors from the original 4004. And as you see, as near as we can measure this, we had something like a 20,000-fold improvement in computing performance over this time frame. And the slope shows no sign of changing. I think we'll be able to continue this for quite a while by exploiting the capability of this technology when we combine with the advantages that are being made in design.

I don't know quite what this is going to enable in the future, but I have met very few people in your kinds of positions who haven't felt they couldn 't take advantage of greater computing power.

Now, a little history to show more graphically, maybe, how some of these things have changed. This is a photomicrograph of the first planar transistor. I like to show this one because I think it's the only product that I ever designed myself that actually went into production.


DR. GORDON MOORE: The 764 micron is not a magic number. That's just a translation of 30,000ths of an inch. We used to work in the English system in a previous life. And that technology was extended by Bob Noyce's inventions of isolation interconnection to let us make a complete integrated circuit.

This is the remaining photograph of the very earliest integrated circuits at Fairchild. This was actually a flip-flop. I think one of the ones we were trying to sell to that nameless aerospace company. It's not a very pretty picture because the etching to make the round die kind of caught at least one of the bond pads, and left something that would be pretty hard to make connections to.

The round die was designed to fit within a lead circle in an old transistor can where when you put more than the three leads on. We put actually eight leads on a transistor can, and each one of these little pads would light up adjacent to it on a bond pad so we can make a little blob of conductive epoxy on each one. We didn't think we would make as many as six lead bonds reliably in a single device in those days.

That, of course, is somewhat different than we make today in our modern microprocessors. This is the core processor, the Pentium II processor, some seven and a half million transistors in the chip. Four layers of metal, .35 micron processor. We will move to the quarter micron very shortly. Quite a far cry from that original integrated circuit shown on the previous slide. And a transistor today in cross-section is really, to me, spectacular. The gate electrode shown here, the spacers on the side to reduce some of the capacitances. That black line that goes underneath the thing called gate is where the gate insulator goes, so thin that even at this extremely high resolution under an electron microscope, it doesn't show up more than as just a simple line there.