Lithography liquid immersion

Positive-type resist compositions, (I), were prepared by Ishiduka et al. (1) containing adamanthyl, 7-butyolactonc, and a perfluoroalcohol component for use in liquid immersion lithography. Perfluoro acetal and ketal, (II), monomers... 

Rothschild, M., Bloomstein, T.M. et al. (2004) Liquid immersion lithography why, how, and when Journal of Vacuum... 

Optical lithography, in compound semiconductor processing, 22 193 Optically active citronellol, 24 506 Optically transparent porous gel-silica, 23 75, 76 Optical materials nonlinear, 17 442-460 second-order nonlinear, 17 444—453 third-order nonlinear, 17 453-457 Optical memory, photochromic material application, 6 602 Optical microscopy, 16 467-487 history of, 16 467-469 in kinetic studies, 14 622 liquid immersion, 15 186 Optical mode density, 14 849, 850-852 Optical multichannel analyzers (OMAs), 23 143... 

The main difference between dry and immersion lithography is the fact that the exposure is done in air in dry lithography and in a liquid (water) in immersion lithography. To prevent the leaching of resist components into the immersion water, topcoats are often used. It should be mentioned that topcoats do not prevent water from leaching into the resist film. The topcoat layer is removed after the exposure and PEB steps, but before development. 

In addition, bicyclohexyl was tested dynamically on patterns found to be extremely hydrophobic with water. In contrast to water, however, this next generation-type immersion lithography liquid was extremely wetting on both of these substrates. Observations indicate that a pattern with a smaller length scale and/or more hydrophobic substrate material would be required to induce the effects achieved with water. 

Since the next generation of immersion lithography will potentially require high index of refraction liquids, the dynamic performance of one such liquid, bicyclohexyl, was examined. First, wafer 4 was tested in the perpendicular direction because it was shown to have the most hydrophobic pattern with water. However, extremely... 

Nano-patteming was found to allow for extremely high critical liquid loss velocities, which may be extremely useful to applications such as immersion lithography, as long as air trapping is acceptable. 

Development. Resist development is a critical step in lithography, because it exerts great influence on pattern quality. The traditional development method uses a liquid developer solution that preferentially dissolves either the exposed region (positive resists) or the unexposed region (negative resists). Development can be carried out by either spray or immersion tech-... 

Lithography In order to precisely resolve the nanometer structures in microelectronics, various enhancement techniques have been applied to the current optical exposure tools that are equipped with deep UV light (193 nm wavelength). These enhancement techniques include phase-shift masks and immersion lenses (putting a liquid between final lens of the stepper and the wafer). The trade-off for the high resolution of modern steppers is an extremely small depth of focus (DOF) that is around 0.5pm over a typical field size of... 

---