The term “roadmap” implies something (a document, a pictorial representation, etc.) that provides the guidance to get from one point to another. Due to the lack of a direction in developing large scale nanotechnology applications (author’s opinion), there is a large scattering of uncoordinated efforts to develop various nanotechnology materials and applications.
The Semiconductor Industry has been employing technology roadmaps since at least the early 1990s. This guiding document had been called the “International Technology Roadmap for Semiconductors” (ITRS) [Ref. 1]. It has become the “International Roadmap for Devices and Systems” (IRDS) [Ref. 2], This name change recognizes the fact that the challenges of continual shrinkage bring other aspects of design and manufacturing into the overall equation.
Why is a roadmap needed? Using a simplified, hypothetical example, consider building a novel type of automotive engine. In this case, consider a hydrogen fueling vehicle. While there are some companies that are already experimenting with this type of fuel, there is no widespread application. Among the initial problems that had to be solved was the composition and storage of the fuel. Liquid hydrogen must be cooled to less than 33K to be in a liquid state. That is both difficult and provides a potential explosive situation. The next step is the development of some intermediary type of composition that will not provide a possible public danger and will not evaporate when the vehicle is stored. So, the hydrogen is not stored as cooled liquid but is developed into a fuel cell, which is safe. The advantage of the hydrogen fueled vehicle is that the resultant of the combustion is water. Once the fuel composition is developed, there is a need to create a means of obtaining the fuel. There have been a very small number of “filling” stations created for refueling the hydrogen powered vehicles. That is the ISSUE! When developing a vehicle that needs to be refueled, there must be places to refuel it. Without a readily accessible source of fuel, a large number of people will not purchase the vehicle.
Back to semiconductors. In the early 1990s, one company developed a 248nm lithograph tool. (The 248nm is the source wavelength for the tool.) The shorter the wavelength, the smaller the features that can be created. Moore’s Law is a reflection of the fact that smaller features result in increased capabilities in the same surface area. The situation that emphasized the need to the technology roadmap was the 248nm lithography tool. The tool performed well and would permit the increase in density of the semiconductors. The introduction of the first of the 248nm tools into production did not happen! More is needed in addition to an improved tool. It the simplest form, the tool, the means of imaging the patterns (this included the resist and the equipment for applying the resist), the development of the patterns (images), and a means of inspecting the results. What was initially lacking was a resist that could withstand the rigors of volume production. Basically, this is the oft repeated scenario of why a battle was lost due to the lack of a nail for the attachment of a horseshoe to one horses hoof. Every piece of the process must be ready to be inserted into production before he entire system can work. The other issue is when a critical part can not be supplied in sufficient quantities. The Wall Street Journal points this out in an article on a shortage of one component for smartphones and other electronics. [Ref.3] So there must be a completely developed process and the manufacturing volume must be sufficient to satisfy the consumer needs.
So, where does a semiconductor nanotechnology application stand today? The next blog will address this question.