Constraints on removal of Si3N4 film with conformation-controlled poly(acrylic acid) in shallow-trench isolation chemical–mechanical planarization (STI CMP)

2008 ◽  
Vol 23 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Ye-Hwan Kim ◽  
Seung-Mi Lee ◽  
Kee-June Lee ◽  
Ungyu Paik ◽  
Jea-Gun Park
Keyword(s):  
Ionic Strength ◽  
Acrylic Acid ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Shallow Trench Isolation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Carboxylate Groups ◽  
Trench Isolation ◽  
Poly Acrylic Acid

The effect of changes in poly(acrylic acid) (PAA) conformation on removal of Si3N4 film was investigated. PAA was used as a passivation agent by adsorption on an Si3N4 film in shallow-trench isolation chemical–mechanical planarization (STI CMP). Adsorption behavior of PAA on the Si3N4 film and the conformation transition were determined by adsorption isotherms and force measurements using atomic force microscopy (AFM) as a function of ionic strength. AFM results revealed that, as ionic strength increases, the repulsive force between the negatively charged carboxylate groups along the backbone of PAA is reduced due to counterion screening and to the changes of PAA conformation from a stretched to a coiled configuration. At high ionic strength, the coiled conformation of PAA formed a dense passivation layer on the Si3N4 film, which led to suppression of the removal rate of Si3N4 film from 72 to 61 Å/min in the STI CMP process.

Atomic force microscopy study of the role of molecular weight of poly(acrylic acid) in chemical mechanical planarization for shallow trench isolation

2006 ◽  
Vol 21 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Chae-Woong Cho ◽  
Sang-Kyun Kim ◽  
Ungyu Paik ◽  
Jea-Gun Park ◽  
Wolfgang M. Sigmund
Keyword(s):  
Molecular Weight ◽  
Atomic Force Microscopy ◽  
Acrylic Acid ◽  
Chemical Mechanical Planarization ◽  
Nitride Film ◽  
Shallow Trench Isolation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Trench Isolation ◽  
Poly Acrylic Acid

The influence of the molecular weight of poly(acrylic acid) (PAA) on chemical mechanical planarization (CMP) for shallow trench isolation (STI) was investigated. The adsorption behaviors of PAA as a function of molecular weight on deposited plasma-enhanced tetraethylorthosilicate and chemical vapor deposition Si3N4 films were analyzed by the force measurement using atomic force microscopy (AFM). The AFM results revealed that the affinity of PAA with the nitride film is higher than the affinity with the oxide film, and thus a denser adsorption layer on the nitride film is formed with higher molecular weight of PAA, which leads to higher selectivity in STI CMP. Additionally, to determine the correlation between the dispersion stability of the CeO2 resulting from the presence of PAA with different molecular weight and CMP performance, the colloidal properties of the slurry as a function of the molecular weight of PAA were examined.

Electrical AFM Measurements for Evaluation of Nitride Erosion in Shallow Trench Isolation Chemical Mechanical Planarization

2004 ◽  
Vol 838 ◽  
Author(s):  
Yordan Stefanov ◽  
Tino Ruland ◽  
Udo Schwalke
Keyword(s):  
Chemical Mechanical Planarization ◽  
Tunneling Current ◽  
Silicon Surfaces ◽  
Nanometer Scale ◽  
Shallow Trench Isolation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Trench Isolation ◽  
Clear Identification ◽  
Non Destructive

ABSTRACTThis article proposes a new application of tunneling current measurements Atomic Force Microscopy (AFM) for evaluation of silicon nitride stop-layer erosion in Shallow Trench Isolation (STI) Chemical Mechanical Planarization (CMP). Simultaneous topographical and electrical AFM measurements allow a clear identification of ‘open’ silicon surfaces on nanometer scale by enhanced tunneling currents in those areas. The measurement technique is non-destructive and can be successfully implemented for process control.

Effects of abrasive particle size and molecular weight of poly(acrylic acid) in ceria slurry on removal selectivity of SiO2/Si3N4 films in shallow trench isolation chemical mechanical planarization

2007 ◽  
Vol 22 (3) ◽  
pp. 777-787 ◽  
Author(s):  
Hyun-Goo Kang ◽  
Hyung-Soon Park ◽  
Ungyu Paik ◽  
Jea-Gun Park
Keyword(s):  
Molecular Weight ◽  
Surface Roughness ◽  
Acrylic Acid ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Abrasive Particle ◽  
Film Surface ◽  
Nitride Film ◽  
Patterned Wafers ◽  
Poly Acrylic Acid

The effects of the molecular weight and concentration of poly(acrylic acid) (PAA) with different primary abrasive sizes in ceria slurry on the nitride film loss, removal rate, film surface roughness, and removal selectivity of SiO2-to-Si3N4 films were investigated by performing chemical mechanical polishing (CMP) experiments using blanket and patterned wafers. In the case of the blanket wafers, we found that for a lower PAA molecular weight, the removal selectivity of SiO2-to-Si3N4 films increased more significantly with increasing PAA concentration in slurry containing a larger primary abrasive size. For the patterned wafers, with a higher PAA molecular weight in the ceria slurry suspension, the erosion of the Si3N4 film was less, but the removed amount was also smaller, and the surface roughness became worse after CMP. These results can be qualitatively explained by the layer of PAA adsorbed on the film surface, in terms of electrostatic interaction and rheological behavior.

Selectivity Studies On Tantalum Barrier Layer In Copper CMP

2003 ◽  
Vol 767 ◽  
Author(s):  
Arun Vijayakumar ◽  
Tianbao Du ◽  
Kalpathy B. Sundaram ◽  
Vimal Desai
Keyword(s):  
Barrier Layer ◽  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Electrochemical Techniques ◽  
Copper Metallization ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Analysis Techniques ◽  
Diffusion Barrier Layer

AbstractCopper metallization in sub-0.18 μm semiconductor devices is achieved by combining the dual damascence techniques followed by chemical mechanical planarization (CMP). Tantalum and its nitride have been identified as the diffusion barrier layer for copper metallization. However, the wide differences in properties between copper and tantalum layers result in selectivity problems during CMP process. The aim of this work is to obtain a better understanding on the slurry selectivity for copper and tantalum and to develop slurries with best selectivity performance. In this work, the effect of several chemical parameters (abrasive type, oxidizer type, concentration, pH etc.) was studied through static and dynamic tests using advanced electrochemical techniques and surface analysis techniques. The surface layers of the statically etched copper and tantalum discs were investigated using X-ray photoelectron spectroscopy (XPS) and surface planarity was studied using atomic force microscopy (AFM). Polishing rates results show that alumina-based slurry polished copper very well whereas tantalum removal rate was low. However, for the silica-based slurry the tantalum shows much higher removal rate than copper and better surface planarity was obtained.

Influence of the electrokinetic behaviors of abrasive ceria particles and the deposited plasma-enhanced tetraethylorthosilicate and chemically vapor deposited Si3N4 films in an aqueous medium on chemical mechanical planarization for shallow trench isolation

2003 ◽  
Vol 18 (9) ◽  
pp. 2163-2169 ◽  
Author(s):  
Sang-Kyun Kim ◽  
Sangkyu Lee ◽  
Ungyu Paik ◽  
Takeo Katoh ◽  
Jea-Gun Park
Keyword(s):  
Chemical Vapor Deposition ◽  
Aqueous Medium ◽  
Vapor Deposition ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Chemical Vapor ◽  
Surface Charges ◽  
Shallow Trench Isolation ◽  
Colloidal Properties ◽  
Trench Isolation

The effects of the electrokinetic behavior of abrasive ceria particles suspended in an aqueous medium and the deposited plasma-enhanced tetraethylorthosilicate (PETEOS) and chemical vapor deposition (CVD) Si3N4 films on chemical mechanical planarization (CMP) for shallow trench isolation were investigated. The colloidal characteristics of ceria slurries, such as their stability and surface potential, in acidic, neutral, and alkaline suspensions were examined to determine the correlation between the colloidal properties of ceria slurry and CMP performance. The surface potentials of the ceria particles and the PETEOS and CVD Si3N4 films in an aqueous suspending medium were dependent on the pH of the suspending medium. The differences in surface charges of ceria particles and the PETEOS and CVD Si3N4 films have a profound effect on the removal rate and oxide-to-nitride selectivity of CMP performance.

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