• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.266-269
• /
• 2000

As the device geometry continuously shrink down less than sub-quarter micrometer, DRAM makers are going to replace conventional tungsten-polycide with tungsten bit-line structure in order to reduce the chip size and use it as a local interconnection. In this paper we showed low resistance and leakage tungsten bit-line process with various RTP(Rapid Thermal Process) temperature. As a result we obtained that major parameters impact on tungsten bit-line process are RTP Anneal temperature and BF2 ion implantation dopant. These tungsten bit-line process are promising to fabricate high density chip technology.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.4
• /
• pp.49-57
• /
• 1992

Tungsten film was deposited on the TiN surface in a low pressure chemical vapor deposition reactor and chemical reaction mechanism between TiN surface and ($WF_{6}\;and\;SiH_{4}$ was studied. Interaction of ($WF_{6}\;or\;SiH_{4}$ with TiN surface and tungsten was deposited more easily. $WF_6$ reacted with TiN activated the TiN surface to form volatile TiF_4$ and tungsten nuclei were formed. ($SiH_{4}$ was dissociated on the TiN surface to form silicon nuclei. From RBS and AES analysis, we could not detect the impurities(such as Si or TiF$_x$)at the interface between tungsten and TiN. The adhesion at the W/TiN interface became poor when the deposition temperature was below 275$^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.409-410
• /
• 2008

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.377-378
• /
• 2006

Thermal management technology is a critical element in all new chip generations, caused by a power multiplication combined with a size reduction. A heat sink, mounted on a base plate, requires the use of special materials possessing both high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) that matches semiconductor materials as well as certain packaging ceramics. In this study, nano tungsten coated copper powder has been developed with a wide range of compositions, 90W-10Cu to 10W-90Cu. Powder technologies were used to make samples to evaluate density, TC, and CTE. Measured TC lies among theoretical values predicted by several existing models.

• Journal of the Korean Society for Heat Treatment
• /
• v.36 no.5
• /
• pp.261-269
• /
• 2023

This study aims to investigate the effects of tungsten additions on the microstructure, corrosion characteristics, and hardness of super duplex stainless steel heat-treated at two different annealing temperatures. Under the annealing temperature of 1100℃, the microstructure of the stainless steels consisted mainly of ferrite, while under the annealing temperature of 1000℃, significant amounts of austenite and secondary phases were also observed. In terms of corrosion characteristics in 3.5 wt%NaCl solution, there was not a significant difference due to W addition at the 1100℃ conditions. However, at the 1000℃, a tendency of decreased corrosion resistance was observed with increasing the tungsten content. On the other hand, the micro-hardness of the stainless steel heat-treated 1000℃ showed an increasing trend with tungsten addition. This increase can be mainly attributed to the higher fraction of secondary phases, primarily sigma, known for their high hardness.

• Nuclear Engineering and Technology
• /
• v.54 no.8
• /
• pp.2801-2808
• /
• 2022

The synergistic effect of ZrC nanoparticle pining and Re solution in W matrix on the thermal stability of tungsten was studied by investigating the evolution of the microstructure, hardness and tensile properties after annealing in a temperature range of 1000-1700 ℃. The results of metallography, electron backscatter diffraction pattern and Vickers micro-hardness indicate that the rolled W-1wt%Re-0.5 wt% ZrC alloy has a higher recrystallization temperature (1600 ℃-1700 ℃) than that of the rolled pure W (1200 ℃), W-0.5 wt%ZrC (1300 ℃), W-0.5 wt%HfC (1400-1500 ℃) and W-K-3wt%Re alloy fabricated by the same technology. The molecular dynamics simulation results indicated that solution Re atoms in W matrix can slow down the self-diffusion of W atoms and form dragging effect to delay the growth of W grain, moreover, the diffusion coefficient decrease with increasing Re content. In addition, the ZrC nanoparticles can pin the grain boundaries and dislocations effectively, preventing the recrystallization. Therefore, synergistic effect of solid solution Re element and dispersed ZrC nanoparticles significantly increase recrystallization temperature.

• Electrical & Electronic Materials
• /
• v.8 no.2
• /
• pp.196-203
• /
• 1995

We presented Tungsten and Tungsten Nitride thin films deposited by RF and DC sputtering. It deposited at various conditions that determining the resistivity and sheet resistivity by stabilizing the basic theory. We investigated properties of the resistivity and sheet resistivity of these films under various conditions, temperature of substrate, flow rate of the argon gas and content of nitrogen from nitrogen-argon mixtures. As the temperature of substrate increased and the flow rate of the argon gas decreased, the resistivities of these films reduced by structural transformation. We found that these resistivities were depend on the temperature of substrate, flow rate and electric power. Very highly resistive tungsten films obtained at 10W RF power. On the contrary, we found that films deposited by DC sputtering, from which very lowly resistive tungsten films were obtained. Tungsten nitride thin films deposited by reactive DC sputtering and the resistivities of these films increased as the content of nitrogen gas increased from nitrogen-argon mixture. And also we found the results show very good agreement, compared with experimental data.

• Journal of the Korean Vacuum Society
• /
• v.11 no.1
• /
• pp.22-27
• /
• 2002

We investigated the crystal structure, resistivity, and chemical states change of the tungsten nitride $(WN_x)$ films prepared by reactive sputtering method with various $N_2$ flow ratios. Crystal structures of $WN_x$ films deposited at the $N_2$ flow ratios of 20%, 40%, and 60% were bcc $\beta$-W, amorphous, and fcc $W_2$N, respectively. Surface roughness of $WN_x$ film was smallest when the $WN_x$ film is amorphous. After the air exposure of $WN_x$ films, $WO_3$ layer was formed at the surface of all samples. Both the nitrogen content of $WN_x$ film and the binding energy of W $4f_{7/2}$ peaks increased with increasing $N_2$ flow ratio. However, after $Ar^+$ ion etching, the shift of W $4f_{7/2}$ peaks was not observed with $N_2$ flow ratio due to the amorphization of the $WN_x$ film surface. The resistivity of $WN_x$ films increased with increasing $N_2$ flow ratio.

• Journal of the Korean Vacuum Society
• /
• v.20 no.3
• /
• pp.200-204
• /
• 2011

In this paper, we deposited the tungsten carbon nitride (W-C-N; nitrogen gas flow of 2 sccm) and tungsten carbon (W-C) thin film on silicon substrate using rf magnetron sputter. Then the thin films annealed at $800^{\circ}C$ during 30 minute ($N_2$ gas ambient) for thermal damage. Nano-indenter was executed 16 points on thin film surface to measure the thermal stability, and we also propose the elastic modulus and the Weibull distribution, respectively. This nanotribology method provides statistically reliable information. From these results, the W-C-N thin film included nitrogen gas flow is more stable for film uniformities, physical properties and crystallinities than that of not included nitrogen gas flow.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.5
• /
• pp.812-817
• /
• 2013

This study demonstrates the diffusion bonding process between a tungsten carbide shank (K30) and tungsten carbide (DX5) for micro WC-PCD tool fabrication. A type of nickel alloy was used as the filler met alto improve the bond ability between K30 and DX5. The bonding pressure, time, and surrounding conditions were kept constant. In particular, the normal pressure was controlled precisely under buckling analysis. Diffusion bonding was performed at various operation temperatures (1170-1770 K) by using a specially designed jig. The microstructure on the localized bonded surface was analyzed using scanning electron microscopy and optical microscopy. In the case of diffusion bonding of WCat 1370-1770K, the filler metal melted completely and diffused between the two base metals, and they were bonded more tightly on both sides than at temperatures below 1370 K. Our results demonstrated the importance of sensitive temperature dependence of diffusion bonding.