Browsing by Author "Wang, YL"

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A modified multi-chemical spray cleaning process for post shallow trench isolation chemical mechanical polishing cleaning application
(1998-11-02)
Wang, YL
;
Wang, TC
;
Wu, J
;
Tseng, WT
;
Lin, CF
Chemical mechanical planarization (CMP) has become widely accepted for the formation of device interconnect structures. Shallow trench isolation technology (STI) utilizes CMP and has been applied to deep-sub-micron processes. Poly Si, CVD Si or SiO2 can be grown or deposited in the trench and planarized by a CMP process. However, the typical wafer surface is contaminated with slurry particles and metallic impurities after the CMP process. The silica particles may damage the VLSI patterns and the metallic impurities can induce many crystal defects in Si wafers during the following furnace processing. Therefore, the post CMP clean is a very important step for the STI process. However, the wafer for poly-Si surface is hydrophobic, SiO2 surface is hydrophilic and Si film is very easy to charge up. Thus, the defect can be difficult to remove by a conventional cleaning technique. In this study: we propose the use of a modified multi-chemicals spray cleaning process for post STI CMP cleaning. We used a modified and heated ammonia/peroxide mix (APM) clean with an ammonia pre-soak and an HF step to etch a thin layer for the removal of trapped metallic ions which can be followed by a hydrochloric/peroxide mix (HPM) clean process to assist in the removal of metallic ions. (C) 1998 Elsevier Science S.A. All rights reserved.
A modified multi-chemicals spray cleaning process for post-CMP cleaning application
(1998-01-01)
Wang, YL
;
Liu, C
;
Feng, MS
;
Tseng, WT
;
材料科學與工程學系
Chemical mechanical planarization (CMP) has become widely accepted for the planarization of device interconnect structures in deep submicron semiconductor manufacturing. Attractive features of CMP include (i) global planarization and (ii) low defect and contamination level. The main challenge of cleaning is to remove the residual particles as well as the metallic contamination. In this paper, a modified post-CMP clean up-multi-chemicals spray cleaning process-is addressed in detail. This new process has been successfully applied to both oxide and tungsten CMP cleaning. The process provides comparable defect performance and excellent removal of metallic contamination to the scrubbing process which has been widely accepted in current post-CMP cleaning usage. The new clean up development strategy also contributes to their low cost of ownership (Co0) and good process flexibility as well as the minimizing cross-contamination. (C) 1998 Elsevier Science S.A.
A modified multi-chemicals spray cleaning process for post-CMP cleaning application
(1998-01-01)
Wang, YL
;
Liu, C
;
Feng, MS
;
Tseng, WT
;
材料科學與工程學系
Chemical mechanical planarization (CMP) has become widely accepted for the planarization of device interconnect structures in deep submicron semiconductor manufacturing. Attractive features of CMP include (i) global planarization and (ii) low defect and contamination level. The main challenge of cleaning is to remove the residual particles as well as the metallic contamination. In this paper, a modified post-CMP clean up-multi-chemicals spray cleaning process-is addressed in detail. This new process has been successfully applied to both oxide and tungsten CMP cleaning. The process provides comparable defect performance and excellent removal of metallic contamination to the scrubbing process which has been widely accepted in current post-CMP cleaning usage. The new clean up development strategy also contributes to their low cost of ownership (Co0) and good process flexibility as well as the minimizing cross-contamination. (C) 1998 Elsevier Science S.A.
A ULSI shallow trench isolation process through the integration of multilayered dielectric process and chemical-mechanical planarization
(1999-06-22)
Lin, CF
;
Tseng, WT
;
Feng, MS
;
Wang, YL
;
材料科學與工程學系
A multilayer thin film structure (SiO2/SiNx/SiO2) with a one-step chemical-mechanical polish (CMP) process is developed for shallow trench filling and planarization for ULSI devices in the quarter micron regime. By fine-tuning the plasma-enhanced chemical vapor deposition (PECVD) conditions we successfully modified the stoichiometry and other characteristics of the as-deposited SiNx and oxide films. As these film characteristics are changed, the CMP removal rate selectivity between sacrificial oxide and nitride stopper layer can also be adjusted. Correspondingly, the CMP process latitude for shallow trench isolation in 0.25 mu m memory devices can be broadened by sequentially depositing multilayered oxide and nitride films with adjustable characteristics and CMP removal rates. Dishing-free wide trench areas with excellent planarity can be achieved through the integration of the proposed multilayered PECVD oxide/nitride scheme and the one-step CMP process. (C) 1999 Elsevier Science S.A. All rights reserved.
Aplication of plasma immersion ion implantation on seeding copper electroplating for multilevel interconnection
(2005-05-01)
Chiu, SY
;
Wang, YL
;
Chang, SC
;
Feng, MS
;
材料科學與工程學系
In this study, an effective seeding technology, plasma immersion ion implantation of palladium (PIII Pd), was proposed to achieve defect-free gap filling for copper electroplating (Cu-ECP). It was found that a threshold dosage (similar to 5.2 x 10(18) m(-2)) of PIII I'd was required to drive Cu-ECP and the dependence of Pd dosage on the implantation time was quasi-linear. The thickness of electroplated copper films increased as the Pd dosage increased. Too high a Pd dosage caused a rough copper film with high resistivity (> 10 mu Omega cm) while too low a I'd dosage resulted in an insufficient nucleation site for Cu-ECP, leading to poor film adhesion. In addition, a higher substrate bias of PIII was suggested to enhance the gap-filling capability of Cu-ECP and the Cu(111) formation of electroplated copper films. (c) 2004 Elsevier B.V. All rights reserved.
Characterization and reliability of low dielectric constant fluorosilicate glass and silicon rich oxide process for deep sub-micron device application
(2001-11-01)
Cheng, YL
;
Wang, YL
;
Liu, CW
;
Wu, YL
;
Lo, KY
Fluorosilicate Glass (FSG) with low dielectric constant currently has been replaced as an alternative to SiO2 for device speed improvement. However, several integration aspects, such as Fluorine (F) distribution, F thermal stability, gap fill capability, capacitance reduction and via resistance of FSG prepared by the high density plasma (HDP) chemical vapor deposition (CVD) method are of concern for sub-0.18-mum devices. In this study, HDP-FSG films show different F concentrations at different locations on an 8-inch wafer. In addition, the FSG film shows poor thermal stability and F diffuses out of the film after high temperature annealing and the pressure cook test (PCT). However, the thermal stability of FSG film can be improved by capping with an oxide layer. The results indicate that silicon rich oxide (SRO) has a better effect at blocking the F diffusion out of FSG films at high temperature than plasma enhanced oxide (PE-OX). For the gap fill capability, HDP-FSG can fill all 0.23-mum gaps and some of the 0.21-mum gaps with an aspect ratio <3.8 but not the 0.19-mum gaps. A 8000 Angstrom HDP-FSG film with 600 Angstrom USG liner and 2000 Angstrom cap layer shows approximately 7.5 to 7.7% capacitance reduction on 0.23/0.23-mum gaps when compared with USG (undoped silicate glass). In addition, FSG has a larger capacitance reduction on the wider metal lines than the thinner metal lines at the same gap size due to a capacitance fringe effect. The via resistance for 0.26 mum unlanded via (which allow minor photo mis-alignment) of HDP-FSG film is also similar to that of USG. (C) 2001 Elsevier Science B.V. All rights reserved.
Characterization and thermal stability of fluorosilicate glass films deposited by high density plasma chemical vapor deposition with different bias power
(2006-03-01)
Hsiao, WC
;
Liu, CP
;
Wang, YL
;
Cheng, YL
;
材料科學與工程學系
High-density plasma chemical vapor deposition (HDP-CVD) fluorosilicate glass (FSG) films were evaluated for the application of intermetal dielectric (IMD) materials in current devices. Film characteristics were examined as a function of deposition/sputter etch (D/S) ratio, which was controlled by the bias power in HDP-CVD. FTIR spectra show that the positions of Si-O and Si-F peaks are independent of the bias power, but the Si-O shifted to a higher wave number and Si-F-2 appeared upon annealing for the films deposited at lower bias power. Stress hysteresis of the FSG films after the first thermal cycle shows a nonequilibrium nature of the microstructure related to impurity content, especially for the film deposited with lower bias power. Thermal desorption of H2O, F, O-2 and Ar were examined, while most of the desorption behaviour can be related to the physical pore structure and pore quantity. (c) 2005 Elsevier B.V. All rights reserved.
Chemical-mechanical polishing of low-dielectric-constant spin-on-glasses: film chemistries, slurry formulation and polish selectivity
(1997-10-31)
Wang, YL
;
Liu, C
;
Chang, ST
;
Tsai, MS
;
Feng, MS
Alkyl siloxane-based low-dielectric-constant (low-k) spin-on-glass (SOG) thin films with varying amounts of organic content were subjected to polishing experiments using silica-and ZrO2-based slurries with a variety of additives, As the amount of organic content in SOG increases, the chemical-mechanical polishing (CMP) removal rate decreases with silica-based potassium hydroxide-added slurry. On the other hand, zirconia-based slurry resulted in higher removal rates for both SOG (>400 nm/min) and thermal oxide and an adjustment in polish selectivity (related to thermal oxide) ranging from 1.2 to 9.1 can be achieved by adding various amounts of tetra-alkyl substituted ammonium hydroxide. Post-CMP materials characterization by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) shows the chemical stability and CMP compatibility of SOG thin films. (C) 1997 Elsevier Science S.A.
Comparison of characteristics and integration of copper diffusion-barrier dielectrics
(2006-03-01)
Wang, TC
;
Cheng, YL
;
Wang, YL
;
Hsieh, TE
;
Hwang, GJ
The characteristics of various copper (Cu) barrier layers, including SiN, SiCN, and SiCO, were investigated in this work. Carbon-based barrier films (SiCN and SiCO) improved the dielectric constant and line-to-line capacitance, but led to sacrifice in film deposition rate, diffusion-barrier performance, and adhesion strength to Cu in comparison with SiN films. In addition, SiN and SiCO films showed the superior electromigration (EM) performance and stress-induced void migration (SM) performance, respectively. Furthermore, the reliability results of SM and EM are strongly related to the barrier film stress characteristics and the adhesion strength between Cu layers. Therefore, optimization of the barrier layer stress and the enhancement of the interfacial condition between Cu and barrier films are crucial to significantly improve reliability. (c) 2005 Elsevier B.V. All rights reserved.
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.
CoSix thermal stability on narrow-width polysilicon resistors
(2006-01-01)
Chen, YM
;
Tu, GC
;
Wang, YL
;
Hwang, GJ
;
Lo, CY
In this study, the thermal stability of polysilicon lines with various widths and different dopant types in 90-nm processes is investigated. The thermal behavior of silicides formed on N+ polyresistors and P+ polyresistors is very different. The worst thermal stability is found on the narrower N+ polyresistors, while an abnormal thermal behavior is observed on P+ polyresistors. This anomalous thermal-stability change with different drawn linewidths of P+ polyresistors is related to the C Grain-size distribution and the actual polyresistor linewidth. Also, it is interesting to find that the voids formed in P+ polyresistors lead to a stepped increase in sheet resistance. (c) 2006 American Vactatin Society.
Direct COSi2 thin-film formation with homogeneous nanograin-size distribution by oxide-mediated silicidation
(2004-09-01)
Chang, JJ
;
Liu, CP
;
Chen, SW
;
Chang, CC
;
Hsieh, TE
By annealing at 460 degreesC for 120 s followed by 600 degreesC 120 s, nanocrystalline CoSi2 thin film with an average grain size of 5 nm can be directly formed from a Co/SiOx/Si multilayer with the SiOx, as a mediated layer. It is found that annealing at 460 degreesC for enough time is crucial for generating enough diffusion channels within the SiOx, layer. After these channels are created, subsequent annealing at 600 degreesC keeps these channels open and is responsible for rapid grain growth. In other words, by using two-step annealing, nucleation and growth processes can be effectively controlled and, hence, the resulting microstructure. The homogeneous nanograin-size distribution is important for ultralarge-scale integration technology below 90 nm to prevent resistance degradation induced by CoSi2, agglomeration. (C) 2004 American Vacuum Society.
Effect of deposition temperature and oxygen flow rate on properties of low dielectric constant SiCOH film prepared by plasma enhanced chemical vapor deposition using diethoxymethylsilane
(2006-02-24)
Cheng, YL
;
Wang, YL
;
Hwang, GJ
;
O'Neill, ML
;
Karwacki, EJ
Low dielectric constant (Low-k) films (SiCOH) were deposited from diethoxymethylsiliane [DEMS; SiH(CH3) (OC2H5)(2)] which has two ethoxy groups along with one methyl group attached to the silicon atoms. The deposited films have been characterized for different oxygen flows, ranging from 50 to 250 standard cubic centimeters per minute (seem). The growth rate is increased with the increasing oxygen (O-2) flow. The absorbance spectrum of Fourier transform infrared spectroscopy shows that the frequency of Si-O stretching vibration mode in the SiCOH film is shifted to a higher wave number with the increase of oxygen flow. It is deduced that the oxygen does not participate in a simple oxidative mechanism, and has no apparent impact on the methyl content even if the relative Si-O content of the deposited films is up to an O-2/DEMS flow rate ratio of 1:1. Also, the refractive index is decreased with increasing the oxygen flow and slightly increased with the deposition temperature. The dielectric constant of the SiCOH is investigated between 2.7 and 3.2, depending on the deposition temperature and O-2/DEMS flow rate ratio, which is lower than that of the current OSG films (k=2.9-3.3). SiCOH films deposited with DEMS only exhibit higher mechanical hardness and lower leakage current than those deposited with both DEMS and oxygen. (c) 2005 Elsevier B.V. All rights reserved.
Effect of deposition temperature, on thermal stability in high-density plasma chemical vapor deposition fluorine-doped silicon dioxide
(2004-05-01)
Cheng, YL
;
Wang, YL
;
Chen, HW
;
Lan, JL
;
Liu, CP
Thermal stability of fluorine-doped silicon dioxide films deposited by high-density plasma chemical vapor deposition as a function of deposition temperature were investigated in this study. Both thermal desorption spectrum and annealing test results show that SiOF films deposited above 400 degreesC have better thermal stability. Furnace annealing data indicate that non -Si-F- bonding fluorine does exist in low-deposition-temperature SiOF films. Furthermore, secondary-ion mass spectrometer results also reveal that the fluorine in SiOF films with a lower-deposition temperature is easily diffused out and turned into the underlayer, which results in less thermally stable SiOF films. Moreover, short-loop simulation results have been subsequently tested and it was concluded that the deposition temperature of the SiOF film is extremely important for thermal stability. (C) 2004 American Vacuum Society.
Effect of substrate on the step coverage of plasma-enhanced chemical-vapor deposited tetraethylorthosilicate films
(2003-07-01)
Lan, JK
;
Wang, YL
;
Chao, CG
;
Lo, K
;
Cheng, YL
Plasma-enhanced chemical-vapor deposition tetraethylorthosilicate (TEOS) films are extensively used as the interlayer dielectric films in multilevel interconnection processes. When TEOS oxide films were deposited on metal patterns three different substrates, titanium nitride (TiN), aluminum (Al), and oxide (SiO2), were used. This study examines the dependence of these substrates on TEOS step coverage. The deposition rates of TEOS oxide revealed that the SiO2 substrate lead to highest TEOS deposition rate during the initial deposition period of 5 s. Then, the TEOS deposition rate of the substrates was nearly the same. The TiN substrate exhibited the highest sidewall step coverage but the sidewall step coverage of the Al substrate deteriorated due to its granular surface. Additionally, different substrates exhibited different coverage of the bottom step. Moreover, the bottom step coverage exceeded the sidewall coverage for all substrates. (C) 2003 American Vacuum Society.
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.
Effects of underlying films on the chemical-mechanical polishing for shallow trench isolation technology
(1997-10-31)
Wang, YL
;
Liu, C
;
Feng, MS
;
Dun, JW
;
Chou, KS
The effects of underlying films on the chemical-mechanical polishing (CMP) removal rate have been studied and characterized. A model for the underlying film mechanical properties such as hardness and Young's modulus, relating to the polishing removal rate was proposed. In addition, a modified shallow trench isolation (STI) process with a thin nitride overcoat has been suggested to eliminate the dishing and oxide remaining on nitride issues. Furthermore, in order to minimize the residual particles and metallic contamination, a modified multi-chemical spray-cleaning process provided for the post-STI CMP cleaning was also studied. (C) 1997 Elsevier Science S.A.
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.
Formation of pyramid-like nanostructures during cobalt film growth by magnetron sputtering
(2005-04-01)
Liu, CP
;
Chang, JJ
;
Chen, SW
;
Chung, HC
;
Wang, YL
Cobalt pyramid-like nanostructures with sharp tips were formed on the surfaces of cobalt thin films grown by magnetron sputtering only when a negative bias was applied. There are two types of pyramids, which grew on top of a columnar grain structure directly from Si(001) substrates. The formation of pyramid-like nanostructures is only selective to a epsilon-Co (hcp) thin film but not a alpha-Co (fcc) thin film, where the basal plane is 10 (1) over bar0 with several well-defined low-energy faceted planes. When grown on Si(111) substrates, the shape of the basal plane changes to a pentagon or other polygon. The island nucleation seems to depend on adatom energy, sputtering rate and the interface stress between the Co thin film and the substrate, but growth is significantly determined by the minimum surface configuration of the structure.
Heat, moisture and chemical resistance on low dielectric constant (low-k) film using diethoxymethylsilane (DEMS) prepared by plasma enhanced chemical vapor deposition
(2006-02-24)
Cheng, YL
;
Wang, YL
;
Lan, JK
;
Hwang, GJ
;
O'Neil, ML
Resistance of low dielectric constant (low-k) dielectrics, deposited using Diethoxymethylsilane (DEMS) precursor and helium (He) carrier gas with or without oxygen (O-2) reaction gas, against heat, moisture stress and chemical treatment is clarified. The low dielectric constant organosilicate glass (OSG) films deposited using DEMS and O-2 is shown to be the most reliable: the dielectric constant are stable even after a heating test at 700 degrees C and a pressure cooker test (PCT) for 168 h. This stability is high enough to ensure the low-k properties throughout fabricating multilevel interconnects and long-term reliability after the fabrication. This is due to the stability of Si-CH3 bonds and more Si-C-Si- bonds, which has high degree of cross-linking. However, the degradation of the dielectric constant occurs after O-2 plasma ashing process. The nitrogen plasma treatment is proposed to prevent the damage from O-2 attack in the low-k films deposited using DEMS precursor. (c) 2005 Elsevier B.V. All rights reserved.