Computer chip fabrication

Electrically insulating and thermally conductive qualities are important in computer chips fabrication. One approach taken is based on boron nitride fillers which offers these two properties. There is also a need to develop materials which are thermally conductive but electrically insulating in high humidity conditions. Polyurethane composites filled with aluminum oxide or carbon fiber can be used for this application. Figure 19.15 shows the effect of the amount of filler on thermal... 

Silicon (Si) Silicon is a lustrous silvery gray material. Because silicon conducts electricity, but not as well as a metal, silicon is classified as a semimetal. Crystals of pure silicon that have been doped with arsenic or gallium are known as semiconductors and are used to fabricate computer chips. Silicone rubbers are polymers containing silicon, oxygen, and various hydrocarbon groups, and are used in applications ranging from sealants to breast implants. 

As discussed in Section 10.6, CVD is a very important process in the microelectronics industry. The fabrication of microelectronic devices may include as few as 30 as many as 200 individual steps to produce chips with up to 10 transistors per chip. An abbreviated schematic of the steps involved in producing a typical computer chip (MOSFEl) is shown in Figure 10-34. 

The research and development of CVD in recent years have focused on solid state microelectronic devices. This rapidly moving technology demands continuously improved materials and processes for the fabrication of even more advanced semiconductor devices. It is well recognized that computer chips would not be manufactured in their current capacity and structure if CVD techniques were not transferred and developed from the material extraction method into the deposition technology. 

In an alternative approach developed by NimbleGen (http //www.nimblegen. com/, Madison, WI), arrays are built using photodeposition chemistry based on a maskless array synthesizer (MAS). The MAS system is a high-density DNA fabrication instrument that uses a maskless light projector as a virtual mask instead of the physical chromium masks used by Affymetrix. The virtual mask is an array of hundreds of thousands of individually addressable aluminum mirrors on a computer chip. These mirrors function as virtual masks that reflect the desired pattern of UV light and are controlled by the computer. 

Usually the construction of a microsized analytical system has components for the following functions sample injection, preparation, separation, and detection. The fabrication of these devices has been facilitated by the application of techniques that were originally developed for computing chip manufacture. While current techniques for computer devices can make features at the nanometer level, for microfabricated analytical devices the usual feature dimensions are more likely at the micron level. 

The growth in the semicon industry has relied on the manufacturing advancement of silicon chip fabrication factories (fab) which can easily exceed two billion dollars in construction costs. Precision of assembly, contamination control (purity), automation, and speed are some of the key contributing factors to the improved productivity of fabs. Consequently, every year more computation power is packed in smaller processors, shrinking device sizes, and lower cost to consumers. 

Nanoscience is the study of the world on the nanometer scale, from approximately one to several hundred nanometers (i). One nanometer (nm) is one billionth of a meter. To put this into perspective, a human hair is approximately 50,000 nm in diameter, the individual components of computer chips are about 65 nm in size and a DNA molecule is 2.5 nm wide. Nanotechnology is the manipulation of molecules and atoms on the nanoscale and fabrication of nanoscale devices. The potential benefits of nanoscience and nanotechnology span diverse areas, including nanoelectronics, medicine, the enviromnent, chemical and pharmaceutical industries, agriculture, biotechnology and computation. 

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