Browsing by Author "Ay, C"

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Integration of a stack of two fluorine doped silicon oxide film with ULSI interconnect metallization
(2004-01-15)
Cheng, YL
;
Wang, YL
;
Liu, CP
;
Wu, YL
;
Lo, KY
Recently, fluorosilicate glass (FSG) has received much attention for application in microelectronics manufacturing due to its low dielectric constant and stable gap-filling ability. Although FSG films have been demonstrated as potential inter metal dielectrics (IMD) for sub-micron devices, integrating a stack of two fluorine doped silicon oxide film deposited on a high-density plasma chemical vapor deposition (HDP-CVD) system for gap filling and a plasma-enhanced chemical vapor deposition (PECVD) system for throughput has not been fully investigated. In this research, an excellent and exceptionally stable process was demonstrated for a stack of HDP-CVD FSG and PECVD FSG layers. Cracks that result from multi-level metal technology were eliminated when higher compressive stress PECVD FSG film was implemented as a capping layer. An 11% capacitance reduction was achieved when comparing a stack of FSG films to undoped silicon oxide. No problem occurred for photo, via etching and chemical mechanical polishing of FSG film. The FSG layer stack's via resistance (Rc(-)Via) as well as a full HDP-FSG scheme is comparable. These results are very promising for the integration of FSG films as inter metal dielectric for devices. (C) 2003 Elsevier B.V. All rights reserved.
Moisture resistance and thermal stability of fluorine-incorporation siloxane-based low-dielectric-constant material
(2004-01-30)
Cheng, YL
;
Wang, YL
;
Wu, YL
;
Liu, CP
;
Liu, CW
The low dielectric constant (low-k) of organo-silica-glass (OSG) and fluorine-incorporated OSG (OFSG) materials produced from plasma-enhanced chemical vapor deposition of trimethylsilane are thermally stable to greater than 600 degreesC. FTIR analysis indicates that Si-CH3 bonds and Si-F bonds remain intact to temperatures well above that normally encountered during integrated circuit manufacture, allowing these materials to maintain a low-k value. While OFSG materials proved to have less hydrolytic resistant than their non-fluorinated analogs during high pressure, high temperature water exposure (pressure cooker test), their leakage current was found to be lower than OSG films before and after wafer exposure. The measured properties of OFSG blanket films suggest that this material is sufficiently robust to ensure stability of reliability after the fabrication. (C) 2003 Elsevier B.V. All rights reserved.
Monitor and eliminate the circular defects in HDP-STI deposition through oxynitride/oxide composite liner
(2004-01-30)
Lan, JK
;
Wang, YL
;
Liu, CP
;
Lee, WH
;
Ay, C
This paper investigates. the monitor and elimination methods for the circular defects in high-density-plasma shallow trench isolation (HDP-STI) deposition process. The optical measurement method can monitor the circular defects in early stage. When the thickness of silane-burst film exceeds 7.8 nm, the fit-error can alert the circular defects. The oxynitride/oxide composite liner can eliminate the circular defects. Besides this, the oxynitride/oxide composite liner can also improve the breakdown strength of the STI oxide. The breakdown strength of the STI oxide increases, respectively, 375 and 30% in the wafer center and edge. The uniformity of the STI breakdown strength was reduced from greater than 200% to less than 10% using the composite liner. The traditional N2O plasma treatment for stabilizing the oxynitride film is harmful in the HDP-STI process. The N2O plasma treatment shows the worst circular defect performance. (C) 2003 Elsevier B.V. All rights reserved.
Study on precipitations of fluorine-doped silicon oxide
(2004-01-30)
Wu, J
;
Wang, YL
;
Liu, CP
;
Chang, SC
;
Kuo, CT
Precipitation on fluorine-doped silicon oxide film (SiOF) was observed while exposure to air for a prolonged period of time (>4 h). Most of the precipitates are less than 1 mum and clustered at wafer center. Under SEM view, the precipitation shows hexagonal shape, and mainly composed of Si and O. SIMS analysis showed that SiOF films without F precipitates showed leveling F% profile, whereas SIMS result for SiOF films with precipitations shows increasing gradient with depth. In this study, factors affecting the precipitation of SiOF film were investigated. Humidity in environment was found to be one of the essential elements for the onset of precipitation. Process optimization and control methodologies were also investigated for precipitation prevention to provide a more robust and stable SiOF film, hence ensuring the reliability of device performance. (C) 2003 Elsevier B.V. All rights reserved.
The application of electrochemical metrologies for investigating chemical mechanical polishing of Al with a Ti barrier layer
(2003-11-15)
Chiu, SY
;
Wang, YL
;
Liu, CP
;
Lan, JK
;
Ay, C
In situ electrochemical measurements were performed for Al and Ti disks in various slurries during polishing and static conditions. The electrochemical results obtained from the corrosion potential drop of Al polishing have verified that the maximum removal rate of metal CMP can be achieved when the removal rate of the surface oxide was equal to its growth rate. However, Ti polishing did not exist maximum removal rate. The effects of H2O2%, pH values and pressure on the Al and Ti polishing behaviors were explored by using potentiodynamic scan. The corrosion potential drop was found to be a good index for polishing removal rate. The corrosion potential drop changed with increasing H2O2% for Al polishing and there existed a maximum value. But the corrosion potential drop increased with increasing H2O2% for Ti polishing. The pH value had different effects on Al and Ti polishing. Higher pH values gave higher Al removal rate but lower Ti removal rate. The Al polishing showed more pressure sensitive than Ti polishing did. The galvanic current was measured for AIM polishing. For slurry with 6 vol.% H2O2 and pH = 4, the abraded Al electrode obtained a negative current, which implied Ti oxidation was enhanced. (C) 2003 Elsevier B.V. All rights reserved.