• Journal of the Korean Vacuum Society
• /
• 제18권5호
• /
• pp.372-376
• /
• 2009

In the modern semiconductor industry, lithography process is used to construct specific patterns. However, due to the decreasing of line width, these days, more and more researchers are interested in PMMA(Poly Methyl Methacrylate) lithography by using e-beam instead of the prior method, PR(Photoresist) lithography by using UV(Ultra-Violet). Additionally, the patterns constructed by lithography are collapsed during the process of cleansing remnants and the resistance against the breakdown of the patterns is known to be proportional to the elastic modulus of pattern-constructing materials. In this research, we measured the change of hardness and elastic modulus of PMMA film surface according to the change of time spent to soft-bake the PMMA film. During the measurement, we controlled the tip pressure from $25{\mu}N$ to $8,500{\mu}N$ having intervals that are $134.52{\mu}N$. For these measurements, we used the Triboindenter from Hysitron to gauge the hardness and elastic modulus and the tip we used was Berkovich diamond Tip.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1446-1449
• /
• 1996

Thin films of diamond-like carbon(DLC) have been deposited using a magnetron plasma-enhanced chemical vapor deposition(PECVD) method with an rf(13.56 MHz) plasma of $C_{3}H_{8}$. From the Langmuir probe I-V characteristics, it can be observed that increasing the magnetic field yields an increase of the temperature($T_e$) and density($N_e$) of electron. At a magnetic field of 82 Gauss, the estimated values of $T_e$ and $N_e$ are approximately $1.5\;{\times}\;10^5$ K(13.5 eV) and $1.3\;{\times}\;10^{11}\;cm^{-3}$, respectively. Such a highly dense plasma can be attributed to the enhanced ionization caused by the cyclotron motion of electrons in the presence of a magnetic field. On the other hand, the negative dc self-bias voltage($-V_{sb}$) decreases with an increasing magnetic field, which is irrespective of gas pressure in the range of $1{\sim}7$ mTorr. This result is well explained by a theoretical model considering the variation of $T_e$. Deposition rates of DLC films increases with a magnetic field. This may be due to the increased mean free path of electrons in the magnetron plasma. Structures of DLC films are examined by using various techniques such as FTIR and Raman spectroscopy. Most of hydrocarbon bonds in DLC films prepared consist of $sp^3$ tetrahedral bonds. Increasing the rf power leads to an enhancement of cross-linking of carbon atoms in DLC films. At approximately 140 W, the maximum film density obtained is about 2.4 $g/cm^3$.

• Journal of the Microelectronics and Packaging Society
• /
• 제19권1호
• /
• pp.61-66
• /
• 2012

Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

• Journal of the Korean Magnetics Society
• /
• 제19권2호
• /
• pp.47-51
• /
• 2009

The surface structure of polycrystalline Fe films of various thicknesses on glass substrates have been studied using a Ti: Sapphire laser at 780 nm. We found that the surface structure possesses C$_s$ crystal structure close to $C_{2v}$ through symmetry consideration. We present one-fold intensity profile with one mirror plane in second harmonic (SH) intensity as a proof of $C_s$ symmetry. $C_s$ and $C_{2v}$ surface symmetries usually appear at the (110) surface of a cubic diamond single crystal [1]. Therefore this surface symmetry would be related to bcc (110) growth orientation coinciding with XRD measurement. Further we treated surface normalized SH asymmetry with various thicknesses. The SH asymmetry increases with increasing of film thickness. From these results, it is observed that the surface structure of thin polycrystalline Fe film below 5 nm is almost isotropic, while in the case of the thicker Fe films, surface structure have $C_s$ symmetry structure close to $C_{2v}$.

• Proceedings of the Korean Vacuum Society Conference
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.144.2-144.2
• /
• 2016

Diamond-like carbon (DLC) coatings have been widely applied to the mechanical components, cutting tools due to properties of high hardness and wear resistance. Among them, hydrogenated amorphous carbon (a-C:H) coatings are well-known for their low friction properties, stable production of thin and thick film, they were reported to be easily worn away under high temperature. Non-hydrogenated tetrahedral amorphous carbon (ta-C) is an ideal for industrial applicability due to good thermal stability from high $sp^3$-bonding fraction ranging from 70 to 80 %. However, the large compressive stress of ta-C coating limits to apply thick ta-C coating. In this study, the thick ta-C coating was deposited onto Inconel alloy disk by the FCVA technique. The thickness of the ta-C coating was about $3.5{\mu}m$. The tribological behaviors of ta-C coated disks sliding against $Si_3N_4$ balls were examined under elevated temperature divided into 23, 100, 200 and $300^{\circ}C$. The range of temperature was setting up until peel off observed. The experimental results showed that the friction coefficient was decreased from 0.14 to 0.05 with increasing temperature up to $200^{\circ}C$. At $300^{\circ}C$, the friction coefficient was dramatically increased over 5,000 cycles and then delaminated. These phenomenon was summarized two kinds of reasons: (1) Thermal degradation and (2) graphitization of ta-C coating. At first, the reason of thermal degradation was demonstrated by wear rate calculation. The wear rate of ta-C coatings showed an increasing trend with elevated temperature. For investigation of relationship between hardness and graphitization, thick ta-C coatings(2, 3 and $5{\mu}m$) were additionally deposited. As the thickness of ta-C coating was increased, hardness decreased from 58 to 49 GPa, which means that graphitization was accelerated. Therefore, now we are trying to increase $sp^3$ fraction of ta-C coating and control the coating parameters for thermal stability of thick ta-C at high temperatures.