As device geometries shrink and customer demands for more stringent zero-defect imagers increases, epitaxy growth is becoming an increasingly critical procedure in microelectronic processing. Therefore, the defects manifested by the epi growth are also an important concern. More specifically, epitaxial layer stacking faults can be detrimental to device performance and, in the case of image sensor devices, they have been shown to cause bright pixels and bright columns in the dark field. Assisting the Image Sensor Solutions Division of Eastman Kodak Company, the ability to screen and monitor incoming silicon has been accomplished and assessed using an unpatterned wafer particle inspection system, the Tencor 6220 Surfscan. A technique has been developed to review and characterize the defects mapped by the Tencor 6220. Initial evaluations show that 29% of the light scattering defects are stacking faults on incoming silicon. Dialogue has improved with the vendors to better align incoming silicon qualification processes with the customer requirements. Incoming silicon qualification procedures have been improved and optimized to reduce any potential yield loss due to incoming silicon defects and stacking faults.
Perry, Alexa M.
"Characterization of Epitaxial Layer Stacking Faults,"
Journal of the Microelectronic Engineering Conference: Vol. 13
, Article 19.
Available at: http://scholarworks.rit.edu/ritamec/vol13/iss1/19