Resist contact printing

Negative DUV resist systems have also been developed, some of which have demonstrated extremely high sensitivity. These include poly (butyl a-chloroacrylate) (55) which is reported to be at least 500 times as sensitive as PMMA and partially chlorinated, narrow dispersity poly(p-vinyl toluene) (84), which has been imaged at 0mJ/cm in contact print-... 

Fig. 10.10. Micro-contact printing process. Schematic illustration of two methods for producing high resolution stamps. The first step of both involves patterning a layer of resist on a flat substrate. This structure, known as the master , is converted to a stamp either by etching or by molding. In the first case (right frames), the resist acts as a mask for etching the underlying substrate. Removing the resist yields a stamp. This structure can be...

Micro-contact printing (pCP) uses high resolution rubber stamps with inks (e.g. alkanethiols) that form self assembled monolayers (SAMs) on the surface (e.g. thin gold film) that is printed [13]. In one pCP approach, these SAMs act as resists for etching material in the unprinted areas, as illustrated in Fig. 10.11. 

Reported volume resistivities for printed patterns formed from commercial silver-based inks are higher than that of bulk silver. This occurrence reflects the fact that sintered ink patterns contain non-ideal defects such as incomplete particle-to-particle contact, incomplete sintering between contacting particles, residual porosity, and the presence of non-conductive additives. The morphology and extent of void formation in two representative sintered silver nanoparticle inkjet inks are illustrated in Fig. 1. 

During the early years of the microelectronics industry, the imaging process used to define the layers of patterned conductor, insulator, and semiconductor materials that constitute active devices was accomplished by using contact printing in conjunction with resists based on photo-induced cross-linking to generate differential solubility. The resolution of the processes in... 

DUV contact printing offers a potential for delineating submicrometer features with high aspect ratio (Figure 3.19), but suffers from mechanical defects caused by the intimate contact between a mask and a resist film. In contrast. 

Experiments with the KrF laser (248 nm) and the inorganic resist Ag2Se-GeSe2 were reported by Polasko et al. (210). These researchers obtained well-controlled 0.5-jim line space arrays by contact printing using a... 

In this equation, is half the grating period, s is the gap between the mask and the photoresist surface, X is the wavelength of the exposing radiation, and d is the photoresist thickness. For contact printing s = 0 and from equation (3.1), with X = 400 nm and a 1 /zm thick resist, the maximum resolution is slightly... 

Biebuyck, N.B. Larsen, E. Delamarche, and B. Michel, Lithography beyond light micro contact printing with monolayer resists, IBM J. Res. Dev. 41 (1997). 

In contact printing [see Fig. 13.24(a)] the mask and the photoresist-coated substrate are in direct contact during exposure, with the mask held chrome-side down on the resist film. Patterns on the mask are transferred to the entire wafer hy broadband radiation. The theoretical resolution hmit of contact printing is given by ... 

However, due to the defectivity problem associated with contact printing, as discussed above, the first noncontact aligners, called proximity aligners, were introduced in 1973 by Kasper Instruments. In proximity printing mode, the mask does not come into direct physical contact with the wafer [see Fig. 13.24(a)]. Rather, it is held 10-25 p.m above the upper surface of the resist-coated wafer. This gap, however, limited resolution on account of diffraction. The theoretical resolution limit of proximity printing is given by the expression... 

Figure 15.4 SEM image of 80-nm contacts printed with the SCALPEL exposure tool in 750-nm-thick DUV resist. (Reprinted with permission from Ref. 71. 1999 IEEE.)...

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