Browsing by Author "Chen, KW"

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Copper surface protection with a completely enclosed copper structure for a damascene process
(2004-01-30)
Wang, TC
;
Hsieh, TE
;
Wang, YL
;
Wu, YL
;
Lo, KY
As integrated circuit manufacture moving to copper interconnection for the most advanced products, protection of copper (Cu) surfaces becomes a major challenge for the back-end-of-line manufacturing process. The damages on Cu, such as Cu corrosion and oxidation, are often observed on wafers when exposing bare Cu surface in the presence of moisture and/or acidic gases. Furthermore, the Cu oxide results in poor adhesion both at Cu/barrier layer and Cu/stop layer interfaces. In this work, a novel Cu dual damascene structure which completely encloses the Cu surface with a tantalum nitride layer is presented. This capping layer avoids the Cu corrosion and oxidation due to its ability to keep moisture and acid off and away from the Cu surface. (C) 2003 Elsevier Science B.V. All rights reserved.
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.
Evaluation of advanced chemical mechanical planarization techniques for copper damascene interconnect
(2004-01-30)
Chen, KW
;
Wang, YL
;
Liu, CP
;
Yang, K
;
Chang, L
According to rapid development of CMP technology, the difference of polishing methods would be applied for copper damascene interconnect. These methods include conventional rotary, linear, oscillation platform. The advantages of these platform would highlighted in uniformity control, stability of removal rate, planarization efficiency, throughput promotion, lower cost of ownership, even dishing and erosion effect integrated with slurry. This paper presented our experience to compare the uniformity, removal rate and planarization efficiency of Cu-CMP between various polishing platforms. In convection, the rotary or oscillation platform would be usually applied in oxide and tungsten CMP, due to the robust air-back carrier and rigid platen to polish the wafer, which performs the good reliability on wafer-to-wafer thickness and endpoint detection. However, the linear polisher is made of the air-bearing moving belt and self-rotated carrier and would provide the wider uniformity and planarization control window than others. In addition,, the simulation model would explain the difference from mechanic design and wafer moving paths between various polishing techniques. Hence, the trade-off advantage and application between various platforms would be compensated and integrated with slurry, conditioners and coming thickness profile from copper plating. It can achieve the optimization of Cu-CMP process. (C) 2003 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.
Molecular epidemiology of long-term colonization of Candida albicans strains from HIV-infected patients
(2006-04-01)
Li, SY
;
Yang, YL
;
Chen, KW
;
Cheng, HH
;
Chiou, CS
Twenty-one Candida albicans isolates from three HIV-infected patients were collected over a period of 3 years and characterized for fluconazole susceptibility, infectivity and genetic relatedness. Fluconazole resistance was found in five isolates, four exhibited dose-dependent susceptibility and the remainder were fully susceptible to this agent. Pulsed-field gel clectrophoresis of SfiI restriction digests of the genomic DNA from the isolates revealed that isolates from the same swab specimen were identical despite differences in Susceptibility to fluconazole and isolates recovered over time from the three patients retained clonally related DNA fingerprints within each patient. This small-scale study confirms the persistence of oral colonization of C. albicans strains in HIV-infected patients. Clinical data also suggests that the primary infecting strain may become a persistent colonist in the oral cavity once the immune function of the patient has been restored.
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.
Novel strategies of FSG-CMP for within-wafer uniformity improvement and wafer edge yield enhancement beyond 0.18 micro technologies
(2001)
Chen, KW
;
Wang, YL
;
Chang, L
;
Liu, CW
;
Lin, YK
The low-K films and higher multiple stacked layers would be widely applied for ultra large-scale integrated circuits [1][2]. However for 8" (200mm) or 12" (300mm) wafer the phenomena of wafer edge collapsing in higher interlayer low-K dielectric film causes from CMP polishing effect. (Shown in Fig. 1). Conventionally a amount of work has been developed in the optimization of different parameters, such as low pressure and high speed [3], metal dummy filling [4], harder pad used [4], and design of polishing head in order to resolve the problems. But these methods only engaged in design of experiment, not addressed in CMP theory of edge collapsing and controlling way. In this paper we will discuss the theory applied in Preston equation to explain the polishing behavior in wafer edge. In advance, to implement the theory, we adopted novel strategies, including of different polishing head (sweep) vibration and pad edge sprayer methods, even new wafer retaining ring design and novel delivery slurry methods in advance. The characteristics of within wafer nonuniformity and edge profile against CMP polishing low-k films, fluorinated silicate glass (FSG), would be evaluated in this new strategy action. Besides, the dimension of metal line and VIA, and edge die-yield can be directly responded to the edge profile improvement. From the action results, the average 7 similar to 10% yield improvement of 0.18 technology can be achieved, especially 15% edge-die yield improvement. The edge profile could promote the phenomena of no collapsing from the original 75 mm to 95 mm of wafer center-to-edge distance, excluding 3 mm edge of 8-inch wafer. These high efficient strategies for within-wafer planarization and edge profile is also proven and fulfilled with the reducing over 50% VIA CD deviation on the rule of lithography.
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.
Scoring method for tumor prediction from microarray data using an evolutionary fuzzy classifier
(2006)
Ho, SY
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Hsieh, CH
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Chen, KW
;
Huang, HL
;
Chen, HM
In this paper, we propose a novel scoring method for tumor prediction using an evolutionary fuzzy classifier which can provide accurate and interpretable information. The merits of the proposed method are threefold. 1) The score ranged in [0, 100] can further illustrate the degree of tumor status in contrast to the conventional tumor classifier. 2) The derived score system can be used as a tumor classifier using a system-suggested or human-specified threshold value. 3) The derived classifier with a compact fuzzy rule base can. generate an interpretable and accurate prediction result. The effectiveness of the proposed method is evaluated and compared using two well-known datasets from microarray data and an existing tumor classifier. It is shown by computer simulation that the proposed scoring method is effective using ROC curves of classification.