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Determining the Quality of Sputtered Glass Films

IP.com Disclosure Number: IPCOM000090746D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Pliskin, WA: AUTHOR

Abstract

The quality of either single or composite film layers can be determined by this method. A beam of light is reflected from the film surface of the film, using a standard spectrophotometer. The reflected intensity versus wavelength is plotted. In good quality films, the reflected intensity, as compared with the reflected intensity from a silicon surface, is relatively constant, except for maxima and minima fringes due to interference phenomena, over the wavelength region 2000 angstroms to 7000 angstroms and greater. However, with poor quality films there is a fall-off of intensity at the lower wavelengths due to either light scattering or absorption or both.

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Determining the Quality of Sputtered Glass Films

The quality of either single or composite film layers can be determined by this method. A beam of light is reflected from the film surface of the film, using a standard spectrophotometer. The reflected intensity versus wavelength is plotted. In good quality films, the reflected intensity, as compared with the reflected intensity from a silicon surface, is relatively constant, except for maxima and minima fringes due to interference phenomena, over the wavelength region 2000 angstroms to 7000 angstroms and greater. However, with poor quality films there is a fall-off of intensity at the lower wavelengths due to either light scattering or absorption or both.

This method has an additional advantage that the same spectrum can be used for determining the glass film thickness. Furthermore, the reflection interference techniques can also be extended to determine the thickness of the glass or oxide layer under a sputtered or fused glass layer as well as the thickness of the top layer of the composite film. In evaluating a composite film, the light is reflected from both the interface between films 10 and 12, and the interface between film 12 and substrate 14 as well as from the top of film 10. In some cases the refractive indices of films 10 and 12 are similar and no significant reflection occurs at the interface between films 10 and 12. However, on most wafers, a portion of film 12 is covered with metallic lands 16 and th...