Method and apparatus for determining process layer conformality

摘要

A method for determining conformality of a process layer includes providing a wafer having a grating structure and a process layer formed over the grating structure; illuminating at least a portion of the process layer overlying the grating structure with a light source; measuring light reflected from the illuminated portion of the grating structure and the process layer to generate a reflection profile; and determining conformality of the process layer based on the reflection profile. A metrology tool adapted to receive a wafer having a grating structure and a process layer formed over the grating structure includes a light source, a detector, and a data processing unit. The light source is adapted to illuminate at least a portion of the process layer overlying the grating structure. The detector is adapted to measure light reflected from the illuminated portion of the grating structure and the process layer to generate a reflection profile. The data processing unit is adapted to determine conformality of the process layer based on the generated reflection profile.