Electroplating (ECP) entry related defect improvement study

With the logic device size shrinking to 28nm and beyond, ultra- low k has been introduced to Cu interconnect, which makes ECP Cu gap-fill very challenging. This paper studied ECP entry related defect with special map. Entry related parameter: entry wave form, entry dynamic mode, and additive concentration have been studied to improve this special pattern defect. Suppressor concentration and dynamic mode have obvious impact on this special pattern. A bubble related model has been proposed to explain defect formation mechanism.