Monitoring Critical Process Steps In 3D NAND Using Picosecond Ultrasonic Metrology With Both Thickness And Sound Velocity Capabilities

Amorphous carbon (a-C) based hard masks provide superior etch selectivity, chemical inertness, are mechanically strong, and have been used for etching deep, high aspect ratio features that conventional photoresists cannot withstand. Picosecond Ultrasonic Technology (PULSE Technology) has been widely used in thin metal film metrology because of its unique advantages, such as being a rapid, non-... » read more