Characterization and Optimization of a Bi-Layer BARC

Standing wave effects have been seen throughout the history of microlithography. Due to standing wave effects, the line width control of imaged lines in photoresist is compromised. A technology that has emerged as strong solution for the reduction of standing wave effects is a Bottom Antireflective Coating (BARC) that is deposited onto the wafer before the photoresist deposition. By reducing the substrate reflectivity, the standing wave effects can also be reduced dramatically. The 193 nm photoresist and the bi-layer BARC films were characterized and then optimized to reduce standing wave effects within the 193 nm photoresist. A bi-layer BARC film configuration that reduces the reflectivity to less than 1% for both of the experimental numerical aperture settings of 1.05NA and 1.3NA is the goal of this project and was achieved in the RIT SMFL cleanroom. Also, a single-layer BARC system was designed to reduce substrate reflectivity to less than 1% at a setting of 1.05NA. This single-layer design was used as the control experiment or baseline to prove that a bi-layer BARC design is much more efficient than a single-layer BARC system. Simulations were conducted for the design of the multi-layer lithography systems using ILSim 1.0, an interferometric lithography simulation software as well as a simulation program on the JA Woolam Co., Inc. Variable Angle Spectroscopic Ellipsometer (VASE), which was also used to characterize the 193nm DUV resist. The simulations are run by utilizing the refractive indexes (n) and the extinction coefficients (k) of the films being used, which are the optical characteristics of the films. Imaged lines and spaces were then exposed for each of the two designed film stacks and at the two NA settings as stated above. Imaged lines of 45 nm and 35 nm were obtained at 1.05 NA and 1.3NA, respectively, for the bi-layer system, while only 45 nm lines could be obtained with the single-layer BARC system. Since the project objectives and goals were reached, a brief proposal to push the limits of the bi-layer BARC system to 1.5NA is suggested

The Journal of Microelectronic Research 2005

https://scholarworks.rit.edu/meec_archive/1014/thumbnail.jp

Geographically touring the eastern bloc: British geography, travel cultures and the Cold War

This paper considers the role of travel in the generation of geographical knowledge of the eastern bloc by British geographers. Based on oral history and surveys of published work, the paper examines the roles of three kinds of travel experience: individual private travels, tours via state tourist agencies, and tours by academic delegations. Examples are drawn from across the eastern bloc, including the USSR, Poland, Romania, East Germany and Albania. The relationship between travel and publication is addressed, notably within textbooks, and in the Geographical Magazine. The study argues for the extension of accounts of cultures of geographical travel, and seeks to supplement the existing historiography of Cold War geography

Clinical, psychological and economic effects of antenatal day care for three medical complications of pregnancy: a randomised controlled trial of 395 women

Background: Day care is increasingly being used for complications of pregnancy, but there is little published evidence on its efficacy. We assessed the clinical, psychosocial, and economic effects of day care for three pregnancy complications in a randomised trial of day care versus standard care on an antenatal ward.Methods: 395 women were randomly assigned day (263) or ward (132) care in a ratio of two to one, stratified for major diagnostic categories (non-proteinuric hypertension, proteinuric hypertension, and preterm premature rupture of membranes). The research hypothesis was that for these disorders, as an alternative to admission, antenatal day care will reduce specified interventions and investigations, result in no differences in clinical outcome, lead to greater satisfaction and psychological wellbeing, and be more cost-effective. Data were collected through case-note review, self-report questionnaires (response rates 81·0% or higher) and via the hospital's financial system. Analysis was by intention to treat.Findings: All participants were included in the analyses. There were no differences between the groups in antenatal tests or investigations or intrapartum interventions. The total duration of antenatal care episodes was shorter in the day-care group than in the ward group (median 17 [IQR 5–9] vs 57 [35–123] h; p=0·001). Overall stay was also significantly shorter in the day-care group (mean 7·22 [SE 0·31] vs 8·53 [0·44]; p=0·014). The median number of care episodes was three (range one to 14) in the day-care group and two (one to nine) in the ward group (p=0·01). There were no statistically or clinically significant differences in maternal or perinatal outcomes. The day-care group reported greater satisfaction, with no evidence of unintended psychosocial sequelae. There was no significant difference in either average cost per patient or average cost per day of care.Interpretation: Since clinical outcomes and costs are similar, adoption by maternity services of a policy providing specified women with the choice between admission and day-unit care seems appropriate

Clinical, psychological and economic effects of antenatal day care for three medical complications of pregnancy: a randomised controlled trial of 395 women

Background: Day care is increasingly being used for complications of pregnancy, but there is little published evidence on its efficacy. We assessed the clinical, psychosocial, and economic effects of day care for three pregnancy complications in a randomised trial of day care versus standard care on an antenatal ward.Methods: 395 women were randomly assigned day (263) or ward (132) care in a ratio of two to one, stratified for major diagnostic categories (non-proteinuric hypertension, proteinuric hypertension, and preterm premature rupture of membranes). The research hypothesis was that for these disorders, as an alternative to admission, antenatal day care will reduce specified interventions and investigations, result in no differences in clinical outcome, lead to greater satisfaction and psychological wellbeing, and be more cost-effective. Data were collected through case-note review, self-report questionnaires (response rates 81·0% or higher) and via the hospital's financial system. Analysis was by intention to treat.Findings: All participants were included in the analyses. There were no differences between the groups in antenatal tests or investigations or intrapartum interventions. The total duration of antenatal care episodes was shorter in the day-care group than in the ward group (median 17 [IQR 5–9] vs 57 [35–123] h; p=0·001). Overall stay was also significantly shorter in the day-care group (mean 7·22 [SE 0·31] vs 8·53 [0·44]; p=0·014). The median number of care episodes was three (range one to 14) in the day-care group and two (one to nine) in the ward group (p=0·01). There were no statistically or clinically significant differences in maternal or perinatal outcomes. The day-care group reported greater satisfaction, with no evidence of unintended psychosocial sequelae. There was no significant difference in either average cost per patient or average cost per day of care.Interpretation: Since clinical outcomes and costs are similar, adoption by maternity services of a policy providing specified women with the choice between admission and day-unit care seems appropriate

Family partner intervention influences self-care confidence and treatment self-regulation in patients with heart failure

Background: Heart failure self-care requires confidence in one’s ability and motivation to perform a recommended behavior. Most self-care occurs within a family context, yet little is known about the influence of family on heart failure self-care or motivating factors. Aims: To examine the association of family functioning and the self-care antecedents of confidence and motivation among heart failure participants and determine if a family partnership intervention would promote higher levels of perceived confidence and treatment self-regulation (motivation) at four and eight months compared to patient–family education or usual care groups. Methods: Heart failure patients (N=117) and a family member were randomized to a family partnership intervention, patient–family education or usual care groups. Measures of patient’s perceived family functioning, confidence, motivation for medications and following a low-sodium diet were analyzed. Data were collected at baseline, four and eight months. Results: Family functioning was related to self-care confidence for diet (p=0.02) and autonomous motivation for adhering to their medications (p=0.05) and diet (p=0.2). The family partnership intervention group significantly improved confidence (p=0.05) and motivation (medications (p=0.004; diet p=0.012) at four months, whereas patient–family education group and usual care did not change. Conclusion: Perceived confidence and motivation for self-care was enhanced by family partnership intervention, regardless of family functioning. Poor family functioning at baseline contributed to lower confidence. Family functioning should be assessed to guide tailored family–patient interventions for better outcomes