Hard mask resist materials

The hard mask approach employs ultrathin resist films, typically 100 nm, as the imaging layer, which are coated over inorganic hard mask substrates such as silicon oxynitride, silicon nitride, amorphous carbon, etc. 

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Damascene applications involving silicon-containing resists and silicon-containing hard mask materials with antireflection properties... 

The advantageous properties of these spin-on silicon-containing resists and hard mask materials with antireflection properties make these materials ideal candidates for dual damascene applications (see Fig. 9.10). They offer advantages over the conventional materials because they have better etch selectivity to the resists they also tend not to suffer from the residue issues during etch and removal associated with conventional approaches. They now dominate in these applications, although spin-on carbon hard masks are emerging as worthwhile alternatives. ... 

One of the drawbacks of Si-containing resist and Si-containing hard mask materials is their propensity to outgas during exposure, which might lead to Si02 contamination of optical elements in the exposure tools. SUesquioxane-based materials appear not to suffer from this problem. 

The imaging properties of PVTMSK were studied by spin coating 350-nm-thick films on silicon wafers or on silicon wafers precoated with a 1.5-(xm-thick layer of hard-baked photoresist, exposing them to mid- or deep-UV radiation through a chromium-on-quartz lithographic mask, and developing the pattern as described earlier. This scheme was used to test the intended application of PVTMSK as an imaging material for two-layer resist applications. The densest patterns resolved were composed of l-(xm coded lines and spaces. 

Cure Purpose. All solder mask products require a cure step or process for the solder mask to achieve the desired material properties. Curing typically increases hardness and the thermal and chemical resistance. The desired curing process is determined by the specific solder mask used. Consult the technical data sheet for the product and follow the supplier s recommendations for the appropriate cure. 

Figure 5.6 Lithography by hard X-rays using a proximity gold mask. The X-rays produce a different solubility in etching solutions between the exposed and unexposed regions. This approach is typically used for the fabrication of polymer-based resist with high aspect ratio (a). After that the resist is used as a mold or for structural application (b). The proper choice of a functional material in a weakly or non-cross-linked state such as sol-gel in the xerogel state can offer several advantages for the preparation of functional devices in a one-or two-step process. Film patterning can...

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