Title :
Studies on X-ray reflectivity technique and application in thickness measurements in wafer fabrication
Author :
Rao, Ramesh N. ; Younan, Hua ; Kun, Li ; Foo, Lo Keng
Author_Institution :
Chartered Semicond. Mfg Ltd., Singapore, Singapore
Abstract :
In advanced ULSI technologies, 90nm and beyond, ultra-thin materials play a key role in device performance and its reliability. Conventional optical techniques, which rely on measuring the complex refractive index, do not provide accurate estimate of film thickness for stacks of two or more layers. X-ray reflectivity (XRR) is a reliable method of measuring thickness of composite film stack of total thickness up to 1 μm, irrespective of whether it is crystalline or amorphous and, conducting or nonconducting films. In this paper, the results of correlation studies between XRR and TEM are presented. The emphasis is on thickness measurements of different types of films, which are 100 -15k thick. It is shown that a good agreement is obtained between the two techniques for film thickness less than l000.
Keywords :
ULSI; X-ray optics; X-ray reflection; composite materials; multilayers; thickness measurement; thin films; transmission electron microscopy; 100 to 15000 Å; ULSI technology; X-ray reflectivity technique; amorphous film; composite film stack; conducting film; crystalline film; film thickness; nonconducting films; thickness measurements; ultra-thin materials; wafer fabrication; Conductive films; Materials reliability; Optical device fabrication; Optical films; Optical materials; Optical refraction; Optical variables control; Reflectivity; Thickness measurement; Ultra large scale integration;
Conference_Titel :
Semiconductor Electronics, 2004. ICSE 2004. IEEE International Conference on
Print_ISBN :
0-7803-8658-2
DOI :
10.1109/SMELEC.2004.1620846