Select Committee on Science and Technology Second Report


1.  Members of the Sub-Committee visited NPL at Teddington on 6 March 2002, to see something of the technologies involved in the development and fabrication of computer microprocessors and to discuss issues with NPL experts.

2.  The visiting party consisted of Lord Wade of Chorlton (Chairman of the Sub-Committee), Lord Flowers, Lord Freeman, Lord Hunt of Chesterton, Lord Methuen, Lord Oxburgh, Lord Patel and Baroness Wilcox. The party was supported by the Sub-Committee's Specialist Adviser (Professor Steve Furber) and Clerk (Mr Roger Morgan), and the Select Committee's Specialist Assistant. Dr Sarah Pearce of the Parliamentary Office for Science and Technology was also present.


3.  The Committee was welcomed to NPL by Dr Bob McGuiness, Managing Director, and Dr Kamal Hossain, Director of Science and Technology. Dr McGuiness outlined NPL's role as the United Kingdom's national laboratory for physical standards. As such, its work was in the field of metrology — the science of measurement. International co-operation was vital if there were to be agreed world-wide standards. Alongside NIST in the US and PTB in Germany, NPL was one of the most respected national standards laboratories in the world.

4.  NPL was founded in 1900 as a traditional government laboratory. In 1995, it became a GOCO — a government-owned, contractor-operated institution. 65% of its income came from government (via the DTI); the remaining 35% was competitively earned. Dr McGuiness said that the amount and high standard of the construction work on site (state of the art buildings specifically designed for metrology, with humidity and temperature control and vibration stability) was a testament to NPL's past success and future ambition.


5.  Graham Peggs outlined the progress of technology in the semiconductor industry. Consumer demand was the main driver for more powerful computers, with the main attention on wireless technologies, real-time graphics manipulation, games and gadgets.

6.  Computer chips were immensely complex structures containing tiny components. The tolerances of error and variation were very small; metrology was a vital element in the manufacturing process. Measurement techniques had to stay ahead of the required manufacturing precision — measurements needed to be about ten times as accurate as the performance tolerances.

7.  The semiconductor industry was unusual in producing a forward projection of targets and problems for the industry as a whole. This ITRS "Roadmap" was published and updated with a remarkable degree of consensus — 2,500 firms were involved in the production of the 2001 edition. The ITRS set specific, quantified manufacturing objectives to allow the industry to keep pace with Moore's Law but anticipated that the physical limits of current approaches to metrology would prevent the industry making progress beyond 2011. Radical breakthroughs would be needed if progress were to be maintained.

8.  John Gallop gave an introduction to computing and disruptive technologies. He outlined the three limits constraining the ultimate performance of microprocessors:

    a.  Thermal — Speed could be increased as the electrical energy required to write each bit of information was reduced. However, to avoid random errors, that energy had always to be significantly greater than the temperature-related energy of the environment.

    b.  Quantum — Continuing to reduce the energy involved in writing each bit would eventually result in the flow of so few electrons that the uncertainties inherent in quantum physics came into play. The onset of such conditions would mean that the time taken to write a bit could be reduced further only if the energy required to do so were increased.

    c.  Power dissipation — Increasing either the density of components on a processor or the speeds at which operations were carried out increased the amount of waste heat. To avoid damage through overheating, the energy required to write each bit had to be reduced as density and speed of operation increased.

9.  Dr Gallop then described some areas of science that could lead to dramatic alterations in computer processor technology:

    a.  single electron transistors that would reduce the energy involved in each processor operation;

    b.  spintronic devices that could use the properties of both charge and spin of electrons to make logic gates;

    c.  molecular scale electronics that would allow very small circuits to be constructed by self-assembly rather than lithography;

    d.  biological computing (using protein chemistry to store and process information) might produce compact but relatively slow processors; and

    e.  quantum information processing, which was attracting world-wide research interest, although as much for cryptography as for general computing.

10.  Such technologies were in their infancy, and would require enormous investment before they could have a substantial impact on computer processors. It was probable that, while new technologies would be excellent for certain aspects of information processing, they would have drawbacks for others. The most likely path of development was to continue with the standard CMOS technology at the heart of a processor, but with different components based on alternative technologies built in — making a system on chip.

Tour of Laboratories

11.  The Sub-Committee then visited various laboratories to see some of the highly specialised equipment, some of which had been made at NPL, that was needed for very small-scale metrology. During the tour, there were five brief presentations.

12.  Dr J-T Janssen showed how reducing the diameter of wires — essential to miniaturisation of components on a processor — changed the behaviour of electrons. At diameters over one micron the behaviour was classical, demonstrating the familiar properties of current and voltage dictated by Ohm's law. As diameters reduced, these classical properties began to break down. At a diameter of 0.1 micron — approaching the wavelength of electrons — quantum effects began to emerge, and it became possible to conduct electrons one by one.

13.  Chris Hunt discussed the role of interconnectors in microprocessors. As the density of components on a chip increased, so did the density of input/output (I/O) interconnectors. The physical barriers to getting more I/O connections on a chip using current approaches would soon act as a limit to the rate of increase. Another problem was the dissipation of waste heat from working microprocessors. New substrate materials were being developed to stop processors overheating as the density of components continued to rise.

14.  Martin Seah gave a presentation on analytical metrology at the limits, which outlined some of the techniques employed to measure surfaces and structures on the nanometre scale. Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy, Secondary Ion Mass Spectroscopy all provided excellent results, but the ITRS indicated that the limits of their resolution would be reached over the next 10 to 15 years. At present, many of the instruments (many made in Germany) had markets in both semiconductors and biotechnology. More refined or new instruments might be needed to address the post-CMOS technologies and this was a factor which UK manufacturers would watch closely. The potentially small demand for the refined or new measuring devices would make this a tough market for existing — let alone new — manufacturers.

15.  Graham Peggs and John Gallop then expanded on some of the themes from their earlier presentations with demonstrations of some of the experimental facilities at NPL. The results of experiments using scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) to measure and manipulate individual molecules were shown, and some of the properties and potential applications of carbon nanotubes were discussed.

16.  Although it was not physically possible directly to measure distances smaller than the wavelength of the light or other energy illuminating the object, NPL had developed ways of using X-ray interferometry (XRI) to measure even smaller distances. Working together with the German PTB, NPL had developed a combined STM/XRI nano-scale metrology tool with a wide range of potential applications in the future development and manufacture of microprocessors.


17.  In a general discussion over lunch with Dr McGuiness, Dr Hossain, the various presenters and other NPL colleagues, the following main points were noted.

    a.  The ITRS noted a wide range of metrology issues that, starting in 2003, currently had no solution.

    b.  Metrology was essential not only for manufacture, but also throughout the innovation and development stages.

    c.  Maintaining the momentum of Moore's Law would require radical new approaches on various fronts. (The term disruptive technologies had undesirable negative overtones.)

    d.  NPL had some of the leading expertise in relevant areas of metrology, although this was found in a variety of rather separate projects rather than in a co-ordinated effort applied to microprocessing. This reflected the position in the country as a whole where there seemed to be no mechanisms to draw together the relevant expertise.

    e.  The US was the dominant country in terms of research in relevant areas. Taken together, European countries played a strong role — almost matching US research effort. In the United Kingdom, there were some signs of lack of coherence in research efforts applied to microprocessor development, and better mechanisms for encouraging industrial exploitation were needed.

    f.  In addition to Dr Hossain's involvement in the 13 March seminar, the NPL team would be happy to discuss these issues in an on-the-record public hearing[112] if that would be helpful.

18.  Members endorsed the Chairman's thanks to Dr McGuiness and his NPL colleagues for their hospitality and for a most stimulating and informative day.

112   They did so on 29 May 2002. Back

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