Forming a funnel-shaped nozzle

摘要

Techniques are provided for making a funnel-shaped nozzle in a semiconductor substrate. The funnel-shaped recess includes a straight-walled bottom portion (306) and a curved top portion (304) having a curved sidewall gradually converging toward and smoothly joined to the straight-walled bottom portion, and the curved top portion encloses a volume that is substantially greater than a volume enclosed by the straight-walled bottom portion.