New uses of IC technology will enable better opportunities for optical lithography
11/01/2007
Remember our roots. Sixty years ago in 1947, the transistor was invented at Bell Labs. In 1961, college courses were still teaching vacuum tube technology. By 1963, William Shockley was making individual bipolar transistors at Transitron in Boston. He asked for masks from the David W. Mann Company, which I joined in 1966. At that point, the integrated circuit (IC) had just been invented. One IC had four active devices. Emulsion masks were contact-printed onto 0.75-in. wafers. The smallest features were 25µm.
Today, we can print 35nm features on 300mm wafers with just 6nm of overlay error. Many advances contributed to this progress. Optical projection lithography significantly reduced defects, enabling much larger ICs. Reduction optics, interferometry, fast microprocessors, RIE, wavelength changes, new resists systems, CMP, excimer lasers, and immersion all extended the life of optical lithography. These advances have come from a relentless international research effort sustained by the IC market. Many have predicted the demise of optical lithography, but it hasn’t happened. I’ve stopped guessing when it will die, but now Solid State Technology has put the challenge in front of me.
So what will the next 50 years bring?
Lithography. Moore’s Law cannot be sustained for another 50 years. How far high-NA lenses, immersion fluids, or EUV will take us are important questions for the next 10 to 15 years. But in 50 years, chasing Moore’s Law will not be a productive effort.
Better opportunities for optical lithography will be found in new uses of IC technology. For example, it is now possible to make an array of transistors on glass to control an LCD-TV. This “active matrix” technology is enabling new mobile products such as the iPhone. A lot of bright minds are working on extending active matrix technology to plastic materials. This will happen. As people learn to control electrons in new materials, other markets will appear. For example, advances in flat panel technology may enable production of very low cost solar panels.
Nanofabrication. Optical and e-beam lithography have opened the door to the nano-world. But to understand where nanofabrication is headed, one needs to look back 100 years. In the late 1800s, the basic nature of atoms was finally understood. This set the stage 50 years later for the discovery of the transistor and the IC. Today, a similar set of discoveries is being made. The basic nature of organic living systems is being understood. Already “self assembly” of organic structures can be programmed using pieces of DNA. A greater mastery of the basic technology and its tools is needed before there will be large-scale applications. But this will come. The frontiers of nanofabrication will be reached using organic self-assembly controlled by genetic-like processes.
The basic markets for organic self-assembled nanotechnology will be for medical and agricultural applications. These markets are large enough to sustain an international 50-year research effort, just as IC markets have sustained their research effort. But medical and agricultural markets need organic solutions, so a switch to organic technology is required.
A convergence. The new organic self-assembly technology and the existing inorganic IC technology can be combined. By putting engineered organic layers on top of IC circuits, testing products with very specific, accurate, fast, and low cost organics can be made. Such products should significantly improve medical testing.
The guidelines for the next 50 years are:
- Nothing beats the steady progress that a large number of smart people can make when they stick to the task for 50 years.
- Serving a large market is very important; the market provides motivation and money to sustain the research effort.
- Markets are elastic, not zero sum games; cost and price reductions pay off. Small markets can be converted to large markets.
- The fear of competition is needed to keep everyone moving.
- Most inventions are born from seeds of knowledge that have already been discovered.
- Most large companies play defense not offense, so good ideas need an alternate path to market. Venture capital has provided this alternate path in the US.
If I were a young person choosing a career path today, it would be in the field of genetics and organic self-assembly. Get into the right stream and it will carry you along to many contributions and great success.
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Griff Resor is president of Resor Associates and a member of SST’s Editorial Advisory Board. Contact him at ph 978/263-7826.