title: Three-dimensional imaging of undercut and sidewall structures by atomic force microscopy.
abstract: Sidewall surface roughness is an important parameter in electronic device manufacture. At present, no high resolution technique exists to quantitatively characterize this property for undercut structures created by semiconductor processing techniques. We developed a three-dimensional atomic force microscope (3D-AFM) to measure the surface roughness of undercut sidewalls with nanometer precision. Decoupled from the positional scanner, the 3D-AFM probe had a variable tilt up to 40° off the normal. Nonorthogonal scans resolved the sidewall surface roughness, base width, and acute critical angle for undercut structures, including a metal overhang and the transmission line of a photonic device. Compatible with standard cantilevers, the 3D-AFM demonstrates great potential for characterizing the sidewalls of soft materials such as photoresist.
authors.affiliation: Park Systems Corporation, KANC 4F, Suwon, South Korea. msjcho@ParkAFM.co.kr
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Cho
authors.forename: Byung-Woon
authors.initials: BW
authors.lastname: Ahn
authors.forename: Joonhui
authors.initials: J
authors.lastname: Kim
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Yueming
authors.initials: Y
authors.lastname: Hua
authors.forename: Young K
authors.initials: YK
authors.lastname: Yoo
authors.forename: Sang-il
authors.initials: SI
authors.lastname: Park