Underlayer dielectric

Figure 5.12. The transfer characteristics of LTPS TFTs prepared using a solution-processed gate dielectric (bold solid line), using a solution-processed underlayer dielectric (broken line) and using a conventional process without solution processing (thin solid line), respectively. [Reproduced with permission from Ref. 24. Copyright 2007 Society for Information Display.]...

TABLE 5.3. Characteristics of TFTs with Solution-Processed Gate Dielectric and Underlayer Dielectric... 

Integration of Cu with a dielectric introduces new problems and challenges [1(b), 34-36] (Fig. 19.8). For example, if polyimides are used as intermetal dielectrics, reliability concerns are corrosion of underlying metal and adhesion of metal films to polyimide underlayers [1(b)]. 

FIGURE 17.43 A scratch after copper barrier CMP on a wafer with fragile low-1 material. The left picture shows that the low-1 dielectric is about as weak as the copper line and deforms under the stress of the scratch. Source Fisher P. CAMP 2006. The right picture shows a soft scratch in the field area where the porous low-1 is locally completely removed. The underlayer of TEOS is not damaged. 

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