Thickness measurement of aluminum, titanium, titanium silicide, and tungsten silicide films by x-ray fluorescence

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2096222· OSTI ID:6550301

Ernst, S; Lee, C O; Lee, J J ^[1]

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1. Motorola, Inc., Advanced Products Research and Development Lab., Austin, TX (US)

X-ray fluorescence (XRF) has received a great deal of attention in the last few years as a quantitative means of determining both the stoichiometry and thickness of many different kinds of films. Examples include Ag and Cu films on mica substrates, Sn-Pb alloys on steel substrates, Al-Ti multilayers on Cu substrates and oxide films on silicon substrates. In XRF the sample is irradiated with x-rays which in turn cause x-rays to be given off by the sample. These x-rays that are given off by the sample can then be analyzed both for energy and intensity. The energy of the x-rays is characteristic of the elemental makeup of the sample and the intensity of the x-rays is dependent on how much of the particular element is present. The intensity then can be related to the thickness of a film if the stoichiometry of the film can be assumed constant. With the increased interest in silicides and more recently, the self-aligned silicide (salicide) process (8-10) for VLSI applications, in-line process monitoring of silicide film thickness has become important to integrated circuit manufacturing. In this study, the number of x-ray photons given of by Al, Ti, titanium silicide, and tungsten silicide films on silicon-based substrates was quantified so that a film thickness for an unknown sample could then be determined easily. In addition, XRF is a more accurate technique, limited principally by the accuracy technique, limited principally by the accuracy of the reference used and the amount of time the x-ray photons are counted.

• OSTI ID: 6550301
• Journal Information: J. Electrochem. Soc.; (United States), Vol. 135:8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM
THIN FILMS
X-RAY FLUORESCENCE ANALYSIS
TITANIUM
TITANIUM SILICIDES
TUNGSTEN SILICIDES
ACCURACY
COMPUTER CODES
COPPER
ENERGY SPECTRA
IRRADIATION
LEAD ALLOYS
MEASURING METHODS
STOICHIOMETRY
SUBSTRATES
THICKNESS
TIN ALLOYS
ALLOYS
CHEMICAL ANALYSIS
DIMENSIONS
ELEMENTS
FILMS
METALS
NONDESTRUCTIVE ANALYSIS
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
SPECTRA
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN COMPOUNDS
X-RAY EMISSION ANALYSIS
360605* - Materials- Radiation Effects
360602 - Other Materials- Structure & Phase Studies
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures