Browsing by Author "Li, FY"

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Effects of plasma treatment in the tungsten process for chemical vapor deposition titanium nitride barrier film beyond nanometer technology
(2006-03-01)
Chen, KW
;
Wang, YL
;
Chang, L
;
Li, FY
;
Hwang, GJ
As the device shrunk to 100 nm, the CVD TiN barrier filling would be limited by the process window of contact for both step coverage and plasma treatment. This limitation not only affects the step coverage capability but also poses a challenge to the treatment of the organic film with the small contact hole. In this study, we investigated whether the plasma treatment of the TiN film barrier influences the subsequent tungsten deposition and causes the change of the gapfilling behavior. After the different RF plasma treatment, we found that the resistivity and impurity level of the thin TiN film can influence not only the contact resistance and uniformity, but also the product yield. The over-treatment contacts were found with porous voids in the poor tungsten deposition during the contact filling even after CMP polishing. The resistances of under-treatment contacts would be determined by the impurity level of TiN films. Hence, the optimized TiN deposition and treatment would be critical to the contact resistance and yield performance. (c) 2005 Elsevier B.V. All rights reserved.
Investigation of overpotential and seed thickness on damascene copper electroplating
(2006-02-24)
Chen, KW
;
Wang, YL
;
Chang, L
;
Li, FY
;
Chang, SC
This study found that higher overpotential from higher plating current density and a thinner seed layer resulted in more incorporation of sulfur impurities into a deposited copper film. Our results suggested that the higher plating overpotential resulted in smaller copper grains with more grain boundaries where more impurities were trapped. To achieve a defect-free filling in vias, the optimization of the plating current density and the seed layer thickness was necessary. A copper seed with thickness less than 30 generated a sulfur-rich copper film, while, thickness larger than 200 nm for 0.13-nm technologies, the copper seed led to a poor gapfilling with a void after electroplating. (c) 2005 Elsevier B.V. All rights reserved.
Novel slurry solution for dishing elimination in copper process beyond 0.1-mu m technology
(2006-03-01)
Chen, KW
;
Wang, YL
;
Liu, CP
;
Chang, L
;
Li, FY
The reduction of the copper dishing was investigated by optimizing the copper CMP processes. The reduction method is a novel copper slurry with the organic passivation agent used during the copper polishing to reduce the copper dishing level. The passivation mechanism of the copper polishing was proposed. With the optimized condition of the copper ECD and CMP, the resistivity deviation of 180-mu m square metal pads with 10-80% pattern densities was reduced from over 30% to less than 10%. The amount of the copper dishing was reduced from around 150 nm to less than 30 nm. Finally, 10% increase of wafer yield and better process reliability were achieved. (c) 2005 Elsevier B.V. All rights reserved.
Pattern-dependent copper microcorrosion from CMP
(2004)
Chen, KW
;
Wang, YL
;
Chang, L
;
Chang, SC
;
Li, FY
After chemical mechanical planarization (CMP) processes, copper microcorrosion was found in a specific pattern, which consisted of two sides of small trench islands connected by a long underlayer metal line. The depth of the copper recess was strongly dependent on the length of the underlayer metal line as well as the size of the trench islands. This phenomenon was different from typical photocorrosion; it was suggested to be induced by the additional electrochemical potential from the connection of the trench islands. Auger analysis proves that higher copper oxidation rate occurred on the specific pattern compared to those without connection. In addition, the pattern-dependent microcorrosion was identified by blocking the connection of the trench islands. A proposed model was given to account for the enhanced copper corrosion from the specific patterns during CMP. (C) 2004 The Electrochemical Society.