RESUMEN
In this study, the effects of Cl2 radicals on dry development of spin-coated metal oxide resist (MOR) and changes in its surface binding states were investigated to verify the mechanism of dry development. Dry development characteristics of tin hydroxide (Tin OH), which is one of the MOR candidates for next generation lithography, were investigated as functions of process time and temperature using a Cl2 radicals source. Non-UV-exposed Tin OH film showed a linear etch rate (1.77 nm/min) from the initial thickness of â¼50 nm, while the UV-exposed film showed slower etch behavior (1.46 nm/min) in addition to the increase of film thickness for up to 3 min during the Cl2 radical dry development. UV-exposed photoresist (PR) contained more oxygen (Sn-O bonding) in the film due to the removal of butyl compounds from the clusters during the UV exposure process. Therefore, due to the lower reaction of chlorine radicals with Sn-O in the UV-exposed Tin OH than the other bindings, the non-UV-exposed PR was preferentially removed compared to the UV-exposed PR. As the temperature decreases, the overall etch rate decreases, but the difference in etch rate between exposed and unexposed Tin OH becomes larger. Finally, at a substrate temperature of -20 °C, the non-UV-exposed Tin OH with a thickness of 50 nm was completely removed, while â¼30 nm thick PR remained for UV-exposed Tin OH. Eventually, a negative tone development was possible with Cl2 radical plasma due to the difference in activation energy between the UV-exposed and non-UV-exposed films. It is believed that dry development using Cl2 radicals will be one of the most important process techniques for next-generation patterning to remove problems such as pattern leaning, line edge roughness, residue, etc., caused by wet development.
RESUMEN
Case reports have previously been published describing various complications of cytomegalovirus (CMV) and mucormycosis in patients with HIV/AIDS. We describe the first case of CMV vasculitis and mucormycosis coinfection resulting in necrotizing myofascial cellulitis in an extremity in late stage HIV/AIDS. In AIDS patients, CMV reactivates when the CD4 count falls to less than 50 cells/microL (normal, 720-1440 cells/microL). Transient episodes of neutropenia in patients with HIV/AIDS who have low CD 4 cell counts are a predisposing factor for mucormycosis. These predisposing conditions were both present in our patient. Our case raises the question of CMV vasculitis leading to tissue ischemia as a possible contributing factor to the mucormycosis superinfection.