Characterization of resists and antireflective coatings by spectroscopic ellipsometry in the UV and deep-UV range

Author(s):  
Pierre Boher ◽  
Jean-Philippe Piel ◽  
Christophe Defranoux ◽  
Jean-Louis P. Stehle ◽  
Louis Hennet
1999 ◽  
Vol 592 ◽  
Author(s):  
Pierre Boher ◽  
Jean Philippe Piel ◽  
Jean Louis Stehle

ABSTRACTPrecise characterization of nitride/oxide gate structures becomes a challenging task due to the very thin thickness (<3-4nm), which will be needed in the next generation integrated circuits. Conventional techniques such as spectroscopic ellipsometry in the visible range becomes difficult to apply because of the great correlation between thickness and optical indices. To overcome this problem the following strategy is applied. First, grazing x-ray reflectance is used on all the samples to extract the different layer thicknesses using a simple model. Second, spectroscopi ellipsometry from deep UV 190nm to 850nm is applied and the results fitted with the structural models deduced from the x-ray results. In this conditions the nitrogen content of the films can be precisely determined. This kind of analysis has been made on a series of nitride/oxide gate structures with variable thicknesses and degree of nitridation. Regression results are discussed and compared to x-ray photoemission results obtained on the same samples.


1996 ◽  
Vol 446 ◽  
Author(s):  
P. Boher ◽  
J.L. Stehle ◽  
L. Hennet

AbstractSpectroscopic Ellipsometry (SE) and Grazing X‐ray Reflectance (GXR) techniques are applied for different insulating films to determine precisely the thickness and optical indices of the layers. Antireflective coatings for microlithography in the DUV range are first analyzed. In the infrared range the layers are transparent and one can take into account the optical index of the layers by a simple dispersion law. Thicknesses obtained by this method are checked by the GXR technique. Extraction of the optical indices from UV to IR is made very accurately taking into account different SE measurements at various incident angles simultaneously. Amorphous carbon thin films are also analyzed in the same way. The main difference is that the layer is absorbant in the entire wavelength range. In this case, a first characterization by the GXR technique is essential to extract the thickness of the layer. Then the optical indices of the layer can be extracted very accurately by SE.


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