• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.57-67
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• 2002

Increased signal speed can be obtained in three ways: changing the layout and/or the ratio of the width to thickness of the metal lines, decreasing the specific resistance of the interconnect metal, and decreasing the dielectric constant of the insulating material (intermetal dielectric). Further advancement cannot be expected from changing layout or decreasing specific resistance. The only alternative is to use an insulating material with a lower dielectric constant than other ones used presently. A large variety of polymers has been proposed for use as materials with low dielectric constants for applications in microelectronics. In this review, the properties of selected polymers as well as various fabrication methods for polymer thin films are discussed. Based on the properties described so far, and the requirements for applications as intermetal dielectric material, the possibilities for further developments also are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.159-159
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• 2007

In order to reduce a signal delay in ULSI, low resistive metal and intermetal dielectric material of low dielectric constant are required. Ordered mesoporous silica film is proper to intermetal dielectric due to its low dielectric constant and superior mechanical properties. In this study, ordered mesoporous silica films was synthesized using TEOS (tetraethoxysilane) / MTES (methyltriethoxysilane) mixed silica precursor and Brij-$76^{(R)}$ surfactant. These films had the porosity of 40% and dielectric constant of 2.5. To lower dielectric constant, the ordered mesoporous silica films were surface-modified by HMDS (hexamethyldisilazane) treatment. HMDS substituted -OH groups on the surface of silica wall for -Si$(CH_3)_3$ groups. After the HMDS treatment, ordered mesoporous silica films were calcined at various calcination temperatures. Through the investigation, it was concluded that the proper calcination temperature is necessary as aspects of structural, electrical, and mechanical properties.

• Journal of the Korean Ceramic Society
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• v.45 no.1
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• pp.48-53
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• 2008

In order to reduce signal delay in ULSI, an intermetal material of low dielectric constant is required. Ordered mesoporous silica film is proper to intermetal dielectric due to its low dielectric constant and superior mechanical properties. The ordered mesoporous silica film prepared by TEOS (tetraethoxysilane) / MTES (methyltriethoxysilane) mixed silica precursor and Brij-76 surfactant was surface-modified by HMDS (hexamethyldisilazane) treatment to reduce its dielectric constant. HMDS can substitute $-Si(CH_3)_3$ groups for -OH groups on the surface of silica wall. In order to modify interior silica wall, HMDS was treated by two different processes except the conventional spin coating. One process is that film is dipped and stirred in HMDS/n-hexane solution, and the other process is that film is exposed to evaporated HMDS. Through the investigation with different HMDS treatment, it was concluded that surface modification in evaporated HMDS was more effective to modify interior silica wall of nano-sized pores.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.171-174
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• 1994

The drive towards ultra-large-scale integrated circuits a continuous intermetal dielectric films for multi layer interconection. Optimum condition of remote plasma enhanced chemical vapour deposition(RPECVD) was achieved by orthogonal array method. Chracteristics of SiO$_2$ films deposited by using remote PECVD with N$_2$O gas were investigated. Etching rate of SiO$_2$ films in P-echant was about 6[A/s] that was the same as the thermal oxide. The films a showed high breakdown voltage of 7(MV/cm) and a resistivity of Bx10$\^$13/[$\Omega$cm] at 7(MV/cm). The interface Trap density of SiO$_2$ has been shown excel lent properties of 5x10$\^$10/[/$\textrm{cm}^2$eV]. It was observed that the dielectric constant dropped to a value of 4. 29 for 150 [W] RF power.

• Electrical & Electronic Materials
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• v.8 no.2
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• pp.171-175
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• 1995

Optimum condition of remote plasma enhanced chemical vapor deposition using orthogonal array method was chosen. Characteristics of oxide films deposited by RPECVD with SiH$_{4}$ and N$_{2}$O gases were investigated. Etching rate of the optimized SiO$_{2}$ films in P-etchant was about 6[A/s] that was almost the same as that the high temperature thermal oxide. The films showed high dielectric breakdown field of more than 7[MV/cm] and a resistivity of 8*10$^{13}$ [.ohmcm] around at 7[MV/cm]. The interface trap density of SiO$_{2}$/Si interface around the midgap derived from the high frequency C-V curve was about 5*10$^{10}$ [/cm$^{2}$eV]. It was observed that the dielectric constant of the optimized SiO$_{2}$ film was 4.29.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.71-71
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• 2012

As the critical dimensions of integrated circuits are scaled down, the line width and spacing between the metal interconnects are made smaller. The dielectric film used as insulation between the metal lines contributes to the resistance-capacitance (RC) time constant that governs the device speed. If the RC time delay, cross talk and lowering the power dissipation are to be reduced, the intermetal dielectric (IMD) films should have a low dielectric constant. The introduction of Cu and low-k dielectrics has incrementally improved the situation as compared to the conventional $Al/SiO_2$ technology by reducing both the resistivity and the capacitance between interconnects. Some of the potential candidate materials to be used as an ILD are organic and inorganic precursors such as hydrogensilsequioxane (HSQ), silsesquioxane (SSQ), methylsilsisequioxane (MSQ) and carbon doped silicon oxide (SiOCH), It has been shown that organic functional groups can dramatically decrease dielectric constant by increasing the free volume of films. Recently, various inorganic precursors have been used to prepare the SiOCH films. The k value of the material depends on the number of $CH_3$ groups built into the structure since they lower both polarity and density of the material by steric hindrance, which the replacement of Si-O bonds with Si-$CH_3$ (methyl group) bonds causes bulk porosity due to the formation of nano-sized voids within the silicon oxide matrix. In this talk, we will be introduce some properties of SiOC(-H) thin films deposited with the dimethyldimethoxysilane (DMDMS: $C_4H_{12}O_2Si$) and oxygen as precursors by using plasma-enhanced chemical vapor deposition with and without ultraviolet (UV) irradiation.

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.314-322
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• 1997

The thin film processing and the applicability as a IMD material of SiO2 aerogels providing ultralow dielec-tric properties were studied. The SiO2 aerogel films with 0.5g/㎤ density (78% porosity) and 4000~21000$\AA$ thickness could be prepared at 25$0^{\circ}C$ and 1160 psig by supercritical drying of wet-gel films, which were spin-coated at the spin rate of 1000~7000 rpm on p-Si(111) wafer under the isopropanol atmosphere. The optimum viscosity of polymeric SiO2 sols for spin coating was in the range of 10~14 cP. The main fac-tors being able to control the film thickness and microstructures were found to be sol concentration, spin rpm, and aging time of wet-gel films. The dielectric constant of the SiO2 aerogel thin film was around 2.0 low enough to be applied to the next generation semiconductor device beyond the giga level.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.117-117
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• 2009

최근 고집적화 구조는 저항(resistance)과 정전용량 (capacitance)에 의한 신호 지연 (RC delay) 증가로 인한 혼선 (cross-talk noise)과 전력소모 (power dissipation)등의 문제를 발생시킨다. 칩 성능에 영향을 미치는 제한인자를 최소화하기 위해서는 저저항 배선 금속과 저유전상수 (low-k)의 층간 절연막 (IMD, intermetal dielectric) 물질이 필요하다. 최근 PECVD (plasma enhanced chemical vapor deposition)를 이용하여 증착시킨 유기살리케이트 (OSG, organosilicate glass)는 가장 유망한 저유전상수 물질로 각광받고 있다. 본 연구에서는 제일원리 연구를 통하여 OSG의 전구체 중에 하나인 DEMS 문자를 모델링하고, 에너지적으로 가장 안정한 구조를 찾아서 각 원자 간의 결합에 따른 해리에너지 (dissociation energy)를 계산하고, DEMS가 H-terminated Si 표면과 반응하는 기구에 대해 고찰하였다. 최적화된 DEMS 분자의 구조를 찾았고 DEMS 분자가 결합이 깨져 조각 분자군으로 될 때의 에너지들을 계산하였다. 계산된 해리에너지로부터 DEMS 분자의 O 원자와 C분자의 결합이 깨져서 $C_2H_5$를 조각 분자군으로 생성할 확률이 총 8가지의 경우에서 가장 높다는 것을 알 수 있었다. 8 가지의 해리된 DEMS 조각 분자군들이 H-terminated Si 표면과 반응할 때의 반응에너지를 계산한 결과 표면의 Si 원자와 DEMS 분자에서 $C_2H_5$가 해리되어 생성된 조각 분자군의 O 원자가 결합을 하고 부산물로 $C_2H_6$를 생성하는 반응이 가장 선호된다는 것을 알 수 있었다. DEMS 분자로 증착시킨 OSG에 대하여 제일원리법을 이용하여 계산한 연구는 보고된 바 없기 때문에, DEMS 분자의 각 원자 간의 해리에너지와 Si 기판과의 반응에너지는 추후 연구개발의 중요한 기초 자료가 될 수 있다.