Apparatus and method for monitoring trench profiles and for spectrometrologic analysis

US7372579B2 · kind B2 · utility

Assignees

• Infineon Technologies AG · DE
• NANYA TECHNOLOGY CORPORATION · TW

Inventors

• Zhen Chen · Singapore, SG
• Peter Weidner · Soest, DE
• Pierre-Yves Guittet · Veldhoven, NL
• Alexander Kasic · Dresden, DE
• Barbara Schmidt · Santa Rosa, US
• Anita Klee · Rohrbach, DE

Key dates

• Filing date: Apr 20, 2006
• Grant date: May 13, 2008
• Expiry date: Nov 9, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/0625
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An apparatus for monitoring a trench profile of a substrate includes a radiation-emitting unit for irradiating the substrate with infrared radiation. The intensity and/or polarization state of the infrared radiation reflected from the substrate is measured at a multitude of measuring frequencies. An analyzing unit determines the respective reflectance and relative phase change and/or relative amplitude change in relation to the respective measuring frequency. In addition, a reflectance spectrum, a relative phase change spectrum and/or a relative amplitude change spectrum may be obtained. By performing a Fourier transformation of the respective spectrum, a secondary Fourier spectrum is obtained. The secondary Fourier spectrum plots a virtual amplitude against corresponding values of a frequency periodicity that correspond to a substrate depth. Peaks of the virtual amplitude may indicate reflective planes within the substrate at respective depths. Thus, rough sections in the trench profile may be identified without modeling.