In situ endpoint detection by pad temperature in chemical-mechanical polishing of copper overlay
As the number of metal levels and the wafer size increase, the global planarity and effective removal of metal overlay across the wafer becomes more crucial. Chemical-mechanical polishing (CMP) has been recognized essential to achieve this goal. Accurate in situ endpoint detection and monitoring method significantly improves the yield and throughput. Previous methods have been proposed, which either require the rearrangement of the machine set-up, or can only be implanted on certain types of machines. In this study, a model for pad temperature capable of predicting the endpoint of CMP in situ is established based on the total consumed kinematic energy between wafer and pad. Limited assumptions of thermal and kinematic conditions are made. The model of temperature rise uses the integral of the relative polishing speed and is verified by on-line measurement. Since the coefficient of friction between the pad and dielectric layer is distinguishably lower than that between the pad and the metal layer, the pad temperature increases milder than polishing the metal layer. In use of the proposed regression method applied to the measured temperature rise, the endpoint of the process can be detected.
Prediction of tungsten CMP pad life using blanket removal rate data and endpoint data obtained from process temperature and carrier motor current measurements
Several techniques to predict pad failure during tungsten CMP were investigated for a specific consumable set. These techniques include blanket polish rate measurements and metrics derived from two endpoint detection schemes. Blanket polish rate decreased significantly near pad failure. Metrics from the thermal endpoint technique included change in peak temperature, change in the time to reach peak temperature, and the change in the slope of the temperature trace just prior to peak temperature all as a function of pad life. Average carrier motor current before endpoint was also investigated. Changes in these metrics were observed however these changes, excluding time to peak process temperature, were either not consistent between pads or too noisy to be reliable predictors of pad failure.
Hispanic marketing : connecting with the new latino consumer
* Cultural Marketing: A new understanding * The Composition of the Hispanic/Latino market * The Latino Essense of "Hispanic" * Language Considerations in Marketing to US Hispanics * Enculturation, Acculturation, and Assimilation: A Bicultural Horizon * Latino Subjective Culture: Insights for Positioning * Culturally Informed Research among Latinos * The U.S. Hispanic Marketing Industry * The Digital World of U.S. Latinos * Latino Consumers and the Future of U.S. Marketing