Browsing by Author "Deng, IC"

Now showing 1 - 16 of 16

A novel pretreatment technology for organic low-dielectric material to suppress copper diffusion and improve ashing resistance
(2000-06-01)
Chang, KM
;
Deng, IC
;
Tsai, YP
;
Wen, CY
;
Yeh, SJ
new novel pretreatment technology for integration of organic low-dielectric material in copper interconnects for ultralarge scale integration applications is developed. Using NH3 plasma treatment, two extremely important advantages were achieved in spin-on organic polymer (SOP), including the reduction of copper diffusion and the improvement of ashing resistance. A copper/SOP/Si capacitor structure is used to study the electrical characteristics of SOP film after ashing treatment or postanneal. Higher barrier capability and better ashing resistance can be achieved by the SOP layer after NH3 plasma treatment. After annealing at 500 degrees C for 60 min, secondary ion mass spectroscopy depths profile shows that the Cu atoms do not penetrate into the SOP when they are pretreated by NH3 plasma. Furthermore after the ashing step, the carbon atoms in the SOP film almost remain the same when they are pretreated by NH3 plasma. On the other hand, the concentration of carbon in as-cured SOP is no longer seen. The reason of improving ashing resistance and better barrier capability was due to the organic polymer film rearranging to form a carbon-containing silicon nitride film. (C) 2000 The Electrochemical Society. S0013-4651(99)10-007-7. Ail rights reserved.
Amorphouslike chemical vapor deposited tungsten diffusion barrier for copper metallization and effects of nitrogen addition
(1997-08-01)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
Shih, CW
;
電子工程學系及電子研究所
In this article, we propose an amorphouslike chemical vapor deposited tungsten (CVD-W) thin him as a diffusion barrier for copper metallization. Experimental results gave no evidence of interdiffusion and structural change for Cu/amorphouslike CVD-W/Si samples annealed up to 675 degrees C for 30 min in N-2. At higher temperatures (700 degrees C), Cu penetration results in the formation of eta ''-Cu3Si precipitates at the CVD-W/Si interface. This is due to the crystallization of the amorphouslike CVD-W film above 650 degrees C, rendering the grain-boundary structure and, hence, fast pathways for Cu diffusion. The Cu/amorphouslike CVD-W/p(+)n diodes, thus, sustain large increases in reverse leakage current. In addition, the effects of nitrogen addition by using an in situ nitridation on the amorphouslike CVD-W film are also discussed. The effectiveness of the nitrided barrier is attributed to the blocking of the grain boundaries in the tungsten film by nitrogen atoms. This slows down Cu diffusion significantly. Physical and chemical analyses indicate that interfaces in the Cu/WNx/W/Si multilayer maintain their integrity while the annealing is carried out at 750 degrees C. Moreover, the reverse leakage current densities of Cu/WNx/W/p(+)n diodes remain at 10(-7) A/cm(2) after 725 degrees C annealing. (C) 1997 American Institute of Physics.
Amorphouslike chemical vapor deposited tungsten diffusion barrier for copper metallization and effects of nitrogen addition
(1997-08-01)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
Shih, CW
;
電子工程學系及電子研究所
In this article, we propose an amorphouslike chemical vapor deposited tungsten (CVD-W) thin him as a diffusion barrier for copper metallization. Experimental results gave no evidence of interdiffusion and structural change for Cu/amorphouslike CVD-W/Si samples annealed up to 675 degrees C for 30 min in N-2. At higher temperatures (700 degrees C), Cu penetration results in the formation of eta ''-Cu3Si precipitates at the CVD-W/Si interface. This is due to the crystallization of the amorphouslike CVD-W film above 650 degrees C, rendering the grain-boundary structure and, hence, fast pathways for Cu diffusion. The Cu/amorphouslike CVD-W/p(+)n diodes, thus, sustain large increases in reverse leakage current. In addition, the effects of nitrogen addition by using an in situ nitridation on the amorphouslike CVD-W film are also discussed. The effectiveness of the nitrided barrier is attributed to the blocking of the grain boundaries in the tungsten film by nitrogen atoms. This slows down Cu diffusion significantly. Physical and chemical analyses indicate that interfaces in the Cu/WNx/W/Si multilayer maintain their integrity while the annealing is carried out at 750 degrees C. Moreover, the reverse leakage current densities of Cu/WNx/W/p(+)n diodes remain at 10(-7) A/cm(2) after 725 degrees C annealing. (C) 1997 American Institute of Physics.
Barrier characteristics of chemical vapor deposited amorphous-like tungsten silicide with in situ nitrogen plasma treatment
(1999-07-01)
Chang, KM
;
Deng, IC
;
Yeh, TH
;
Shih, CW
;
電子工程學系及電子研究所
Our team investigated the characteristics of inserting an 80 nm amorphous-like WSi1.6N0.5N/WSi1.6 barrier layer between aluminum film and a shallow diode to retard aluminum and silicon interdiffusion. In one chamber without breaking vacuum, we used a nitrogen plasma treatment to stuff nitrogen atoms into the grain boundaries of amorphous-like tungsten silicide film. The nitrogen atoms eliminated the fast diffusion paths of film, thus giving the amorphous-like tungsten silicide film a smaller diffusion coefficient. We then examined the failure of diodes with amorphous-like WSi1.6N0.5/WSi1.6 barriers which were annealed at 575 degrees C for 30 min and which had leakage currents of 10(7) and 10(8) nA/cm(2). These diodes failed due to the diffusion of aluminum along the sidewalls of the barriers and the field oxide interface. In the search for a solution to this problem we investigated the use of tetraethylorthosilicate, which is known for its thermal stability as a stress buffer. In this experiment we used tetraelhylorthosilicate to form a "contact array structure" which in turn prevented diode failure at 575 degrees C annealing for 30 min, and furthermore, the diodes in the contact array structure only began to show evidence of degradation at 600 degrees C. (C) 1999 The Electrochemical Society. S0013-4651(98)09-086-7. All rights reserved.
Fabrication of cantilever type microswitches using surface micromachining technology
(2000)
Chang, KM
;
Jou, CF
;
Luo, JJ
;
Kuo, LY
;
Deng, IC
Cantilever type microswitches have advantages of low electrostatic actuation voltage and high isolation in RF applications. Of particularly importance, it can be integrated with microstrip line in series or shunt connection mode for building the RF circuit or system directly. Figure 1(a) is an idea switch with single pole, single throw configuration (SPST). As shown in figure 1(b). the microswitch in our study is similar in structure to an ideal switch. Suspended aluminum membrane with perforation holes is used as a movable electrode that will form the resistive contact with the bottom electrode underneath at the free end through electrostatic actuation process. The fabrication processes will be described as shown in figure 2 for constructing the 4 um gap structure of microswitches. Figure 3 shows the structure of microswitch using field emission scanning electron microscope (FESEM). The bending of the membrane was resulted from the thermal histogram of lithography and dry release process in reactive ion etching system, which can be controlled by process parameters optimization. Hysteresis measurement on HP-4156 as shown in figure 4 has demonstrated the operation of microswitch. The actuation voltage shows higher value than expected from simulation due to the existence of residual stress. However, the small curvature of this cantilever type membrane indicates the feasibility of building the application circuit from this low stress membrane microswitches.
Highly selective etching for polysilicon and etch-induced damage to gate oxide with halogen-bearing electron-cyclotron-resonance plasma
(1996-09-01)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
Lin, HC
;
電子工程學系及電子研究所
The investigations of polysilicon etching with three halogen-bearing plasmas (SF6, Cl-2, and HBr) in an electron-cyclotron-resonance reactor have been made. We examine the etching characteristics which include etching rate, anisotropy, and selectivity based on the discussions of the chemical and electrical properties of the F, Cl, and Br radicals, It was found that the degree of anisotropy strongly depends on the deposition of a silicon halide film on sidewall and on the spontaneous etching properties of three halogen plasma mixtures. The selectivity to oxide is related to the amount of silicon halides that are produced during etching poly-Si and the electrically polarized level of these products when they adsorb on the oxide surface. We find that the selectivity on oxide is approximately infinite for the HBr system and over 90 for the Cl-2 system. In addition, the effects of oxygen addition, microwave power, and rf power are also investigated. It was found that the maximum etching rate and selectivity of SF6, Cl-2, and HBr plasmas occurred at concentrations of added oxygen at about 7.5%, 5%, and 3% total flow rates, respectively. The suitable range for the microwave power applied is from 250 to 300 CV and the most respectable value of applied rf power is about 35 W. Concurrently, the local surface charging causing damage to the gate oxide during the overetching period is studied. It is observed that low device yield, large flatband voltage V-fb shift, and high interface-state density D-it are correlated with longer overetch and high antenna ratio structure of the device. A more obvious degradation is observed in the SF6 gaseous system than in Cl-2 and HBr ones. Finally, the influence of magnetic coil current on device damage is also addressed. (C) 1996 American Institute of Physics.
Nitridation of fine grain chemical vapor deposited tungsten film as diffusion barrier for aluminum metallization
(1997-04-15)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A novel tungsten nitride (WNx) film for diffusion barrier applications has been prepared by nitridation of a fine grain chemical vapor deposited tungsten (CVD-W) film. The fine grain CVD-W is deposited at 300 degrees C in a low pressure chemical vapor deposition reactor with a SiH4/WF6 flow rate of 12.5/5 seem under a total gas pressure of 100 mTorr. The subsequent nitridation process is executed in nitrogen plasma at 300 degrees C without breaking vacuum. The thickness of WN, layer as examined by secondary ion mass spectroscopy is 50 nm after 5 min exposure to nitrogen plasma. X-ray photoelectron spectroscopy spectra shows that the atomic ratio of tungsten to nitrogen in WNx, layer is 2:1. According to the analysis by Auger electron spectroscopy and the measurement of n(+)p junction leakage current, the Al/WNx/W/Si multilayer maintains excellent interfacial stability after furnace annealing at 575 degrees C for 30 min. The effectiveness of W2N barrier is attributed to stuffing grain boundaries with nitrogen atoms which eliminates the rapid diffusion paths in fine grain CVD-W films. (C) 1997 American Institute of Physics.
Nitridation of fine grain chemical vapor deposited tungsten film as diffusion barrier for aluminum metallization
(1997-04-15)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A novel tungsten nitride (WNx) film for diffusion barrier applications has been prepared by nitridation of a fine grain chemical vapor deposited tungsten (CVD-W) film. The fine grain CVD-W is deposited at 300 degrees C in a low pressure chemical vapor deposition reactor with a SiH4/WF6 flow rate of 12.5/5 seem under a total gas pressure of 100 mTorr. The subsequent nitridation process is executed in nitrogen plasma at 300 degrees C without breaking vacuum. The thickness of WN, layer as examined by secondary ion mass spectroscopy is 50 nm after 5 min exposure to nitrogen plasma. X-ray photoelectron spectroscopy spectra shows that the atomic ratio of tungsten to nitrogen in WNx, layer is 2:1. According to the analysis by Auger electron spectroscopy and the measurement of n(+)p junction leakage current, the Al/WNx/W/Si multilayer maintains excellent interfacial stability after furnace annealing at 575 degrees C for 30 min. The effectiveness of W2N barrier is attributed to stuffing grain boundaries with nitrogen atoms which eliminates the rapid diffusion paths in fine grain CVD-W films. (C) 1997 American Institute of Physics.
Study of a circularly polarized CPW-fed inductive square slot antenna
(2006-08-01)
Deng, IC
;
Lin, RJ
;
Chang, KM
;
Chen, JB
;
電子工程學系及電子研究所
A novel design of circularly polarized (CP) CPW-fed inductive square-slot antenna is proposed. A right-hand circularly polarized (RHCP) radiation is achieved by an inductive square patch with two adjusted slots and cars. This experimental results show that the bandwidth of 3 dB axial ratio is about 320 MHz (or 13.15%). Prototypes of this proposed antenna is designed for solution of IEEE 802.11 b/g (2.4 GHz). Details of the experimental results are presented and discussed. (c) 2006 Wiley Periodicals, Inc.
Suppress copper diffusion through barrier metal-free hydrogen silisequioxane dielectrics by using NH3 plasma treatment
(2000)
Chang, KM
;
Deng, IC
;
Yeh, SJ
;
Yeh, TH
;
電子工程學系及電子研究所
a low dielectric constant material, hydrogen silisequioxane (FOx-16), can successfully suppress Cu diffusion without barrier metal by using NH3 plasma treatment. After NH3 plasma treatment, the hydrogen silisequioxane film with lower leakage current and better barrier ability was achieved. This film almost keeps the same dielectric constant after different plasma exposure times. The decrease in leakage current with more exposure time is due to dangling bonds passivated by -H bonds on porous hydrogen silisequioxane. The better barrier ability is due to a thin nitride film formed an the dielectric.
Suppression of copper diffusion through barrier metal-free hydrogen silsesquioxane dielectrics by NH3 plasma treatment
(1999-12-01)
Chang, KM
;
Deng, IC
;
Yeh, SJ
;
Tsai, YP
;
電子工程學系及電子研究所
A low dielectric constant material, hydrogen silsesquioxane (FOx-16), can successfully suppress Cu diffusion without barrier metal by using NH3 plasma treatment. After NH3 plasma treatment, the hydrogen silsesquioxane film with lower leakage current and better barrier ability was achieved. This film almost keeps the same dielectric constant after different plasma exposure times. The decrease in leakage current with more exposure time is due to dangling bonds passivated by -H bonds on porous hydrogen silsesquioxane. The better barrier ability is due to a thin nitride film formed on the dielectric. (C) 1999 The Electrochemical Society. S1099-0062(99)06-025-3. All rights reserved.
Suppression of fluorine penetration by use of in situ stacked chemical vapor deposited tungsten film
(1999-08-01)
Chang, KM
;
Deng, IC
;
Lin, HY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this study, amorphous-like tungsten films were deposited by a chemical vapor deposition (CVD) process. The deposited film has shown reduced resistance compared with WSi2, and it also blocked the fluorine atoms from diffusing into the gate oxide. Furthermore, when the amorphous-like tungsten film was deposited prior to a typical CVD tungsten film with a columnar structure, it not only showed excellent barrier characteristics in impeding fluorine impurities, but its resistance was also substantially lower than a single layer of a-W film. It is also found in our work that a bilayer film containing typical CVD tungsten/amorphsus-like CVD tungsten is a better wordline structure due to its extraordinarily low resistivity and low fluorine contamination. (C) 1999 The Electrochemical Society. S0013-4651(98)11-071-6. All rights reserved.
The characteristics of chemical vapor deposited amorphous-like tungsten film as a gate electrode
(1998-09-01)
Chang, KM
;
Deng, IC
;
Shih, CW
;
Lain, KD
;
Fu, CM
Tungsten films are often advantageously formed by the chemical vapor deposition system which using WF6 gas through SiH4 or H-2 reduction. The fluorine species will diffuse into poly-Si/SiO2/[Si] multilayers by a driving force which is the reaction of WF6 and poly-Si gate. When too many fluorine atoms diffused into the gate oxide, the fluorine atoms will cause more strain in the gate oxide and the electrical characteristics of device will shift. An amorphous-like tungsten layer was deposited at a flow rate ratio of 2.5 of SiH4/WF6. The driving force in the amorphous-like tungsten film deposition is far less than that in selective tungsten film deposition; therefore, the concentration of fluorine atoms in the amorphous-like tungsten film is much less than in the selective tungsten film. We proved that only few fluorine atoms were incorporated in amorphous-like tungsten film which has good characteristics in the application of gate electrode.
Thermal stability of amorphous-like WNx/W bilayered diffusion barrier for chemical vapor deposited-tungsten/p(+)-Si contact system
(1999-03-01)
Chang, KM
;
Deng, IC
;
Yeh, TH
;
Lain, KD
;
Fu, CM
The barrier characteristics of tungsten nitride/tungsten (WNx/W) bilayer formed by an in situ nitridation on a thin chemical vapor deposited amorphous-like tungsten (CVD a-W) film in CVD-W/Si contact system have been investigated. The thickness of WNx layer after a 5 min of N-2 plasma exposure at 300 degrees C approximated 50 nm and the atomic ratio of W to N in WNx layer was 2 : 1. In the CVD-W/a-WNx/a-W/Si multilayered sample, no discernible tungsten silicide was detected by X-ray diffractometer (XRD) at W/Si interface after annealing at 750 degrees C. Meanwhile, with the Rutherford backscattering spectroscopy (RBS) analysis and the measurement of p(+)n junction leakage current, the CVD-W/a-WNx/a-W/Si multilayer maintained the integrity of interface and the CVD-W/a-WNx/a-W/p(+)n diode kept the reverse leakage current density less than 9 x 10(-9) A/cm(2) while the post annealing was carried out at 700 degrees C for 30 min. As the experimental results, the effectiveness of amorphous-like WNx/W bilayered diffusion barrier is attributed to stuff grain boundary with N atoms as well as to eliminate the rapid diffusion paths by using CVD a-W material.
Using NH3 plasma pretreatment to improve the characteristics of organic spin-on low-k materials for copper metallization
(2001-11-01)
Chang, KM
;
Tseng, MH
;
Deng, IC
;
Tsai, YP
;
Yeh, SJ
Organic low-k materials have got more attention for reducing integrated circuits RC delay time. A serious problem, in degradation of organic low-k materials is induced by ashing step, In this study, an NH3 plasma-treated spin-on low-k material was used as a dielectric layer for Cu metalization. After NH3 plasma treatment for 10 min, the low dielectric constant films can prevent ashing damage without changing their original dielectric constant. An extra advantage of blocking copper diffusion was achieved after NH3 plasma treatment. The improvement of low dielectric constant films was due to an oxynitride film formed on the surface of low dielectric constant film. This oxynitride film also prevents the Cu diffusion/migration into the underlying dielectric and plays a role of passive diffusion barriers.
Using NH3 plasma treatment to improve the characteristics of hydrogen silsesquioxane for copper interconnection application
(2000-05-01)
Chang, KM
;
Deng, IC
;
Yeh, SJ
;
Tsai, YP
;
電子工程學系及電子研究所
Hydrogen silsesquioxane, a material with low dielectric constant, can successfully suppress Cu diffusion without using a barrier metal by implementing a NH3 plasma treatment. Lower leakage current and better barrier capability can be achieved by hydrogen silsesquioxane film after NH3 plasma treatment. Having been treated with different plasma exposure rimes. this film can still maintain its original dielectric constant with few changes. The decrease in leakage current with increasing exposure time can be attributed to the following mechanisms: dielectric film becomes denser, dangling bonds are passivated, nitride film is formed on the hydrogen silsesquioxane, and the bulk damage of hydrogen silsesquioxane is annealed out. A thin layer of nitride formed on the dielectric is the cause for having better capability. The thickness of the nitride layer on hydrogen silsesquioxane is about 35 nm, and it can prevent the Cu diffusion/migration into the underlying dielectric. The role of our nitride film is to act as a passive diffusion barrier. (C) 2000 The Electrochemical Society. S0013-4651(99)10-093-4. All rights reserved.