There is a strong commercial need in many current and emerging technology fields for direct-write technologies capable of depositing materials, and especially metals and semiconductors, in patterns with features in the micron and sub-micron size regime. While most microelectronic devices are fabricated via photolithography, the need for direct write technologies is particularly evident in the area of additive defect repair and circuit edit. For instance, damaged or defective photomasks are discarded at extremely high costs to the microelectronics industry due to a lack of suitable tools for additive repair of missing material on nanoscale features. On the micron length scale, damage to the metal components of thin film transistor (TFT) arrays in flat panel displays (FPD) is difficult to repair due to the lack of rapid, low cost methods for depositing micron sized conductive traces. Although photolithography can be carried out for fabricating devices, it requires complex and costly instrumentation which makes the technology prohibitively expensive for low volume, high performance components, or prototyping applications. In these cases, other techniques such as direct-write processes could offer unique advantages and capabilities. As the most common direct-write technology, ink-jet printing offers a convenient, flexible method for printing a range of different materials from biological molecules to materials for microelectronics. However, the resolution of the technique is generally limited to 15-200 micron-sized dots, which is not sufficient for many applications (see, for example, U.S. Patent Application 2004/0261700 to Edwards et al.). Other direct-write tools, such as laser-assisted deposition, electron or ion beam lithography, suffer either from similar resolution limitations, are too costly for many applications, or have material restrictions that will preclude their application to the direct fabrication or repair of active and passive microelectronic or optoelectronic components. In particular, electron-beam lithography, ion-beam micromachining, laser- or electron-beam-assisted chemical vapor deposition requires a (partial) vacuum, which is prohibitively expensive for very large flat panels (such as wide TV or computer screens).
USPTO Backgrounds
USPTO Backgrounds