Lithography simplified

Fig. 2 A simplified process flow for making an integrated circuit. Most unit operations fall into one of the five categories deposition, lithography, etching, doping and cleaning.

The photoresist technologies involve many steps each can be characterized by many parameters. It is very difficult to optimize the processes. Previously used pilot experiments now proved to be very costly and difficult. It is not possible to optimize all parameters by performing large series of the lithography experiments, at all possible sets of the parameters. The problem may be simplified and sometimes completely solved by means of mathematical modeling and simula-tion.f ° Photoresist technology simulation provides the opportunity to perform experiments in a virtual environment that can be much faster and cheaper than the full-scale wafer experiments. 

This new submicron technology allows us to produce devices with adjacent elements made of various materials of different thickness by single lithography. These advantages increase the possibilities for device design and simplify the removal of undesirable gases and heat dissipation. 

Multianalyte detection in a single sample has been reported extensively using electrochemical, piezoelectric, electrical resistance, - and oph-capo 11,33 39 methods. The sensor arrays were fabricated by photolithography and soft lithography, - inkjet-, screen-, and pin-prinhng, - and photodeposition.i 34,i4,45 jhese techniques involve labor-intensive multistep fabrication and image analysis and pattern-recognihon codes. The monochromatic or multicolor OLED excitation platform in (micro)arrays would drastically simplify fabrication and reduce cost. 

Because of the potential market size, the possibility of utilizing carbon nanotubes as cold cathode materials for field emission displays has attracted considerable commercial interest. Several major display companies have devoted substantial R D effort in this area. A prototype 9-inch field emission display based on carbon nanotubes has recently been demonstrated. Compared to the lithography-based Spindt-type emitters, the fabrication process can be simplified significantly by using carbon nanotubes as the cold cathodes. However, engineering issues such as emission uniformity and stability have yet to be solved. 

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