TEST PADS FOR MEASURING PROPERTIES OF A WAFER

摘要

Test pads, methods, and systems for measuring properties of a wafer are provided. One test pad formed on a wafer includes a test structure configured such that one or more electrical properties of the test structure can be measured. The test pad also includes a conductive layer formed between the test structure and the wafer. The conductive layer prevents structures located under the test structure between the conductive layer and the wafer from affecting the one or more electrical properties of the test structure during measurement. One method for assessing plasma damage of a wafer includes measuring one or more electrical properties of a test structure formed on the wafer and determining an index characterizing the plasma damage of the test structure using the one or more electrical properties. In addition, systems and methods for controlling deposition of a charge on a wafer for measurement of one or more electrical properties of the wafer are provided. One system includes a corona source configured to deposit the charge on the wafer and a sensor configured to measure one or more conditions within the corona source. This system also includes a control subsystem configured to alter one or more parameters of the corona source based on the one or more conditions. Another system includes a corona source configured to deposit the charge on the wafer and a mixture of gases disposed within a discharge chamber of the corona source during the deposition of the charge. The mixture of gases alters one or more parameters of the charge deposited on the wafer.