Study on Adsorption Behavior of Organic Contaminations on Silicon Surface by Gas Chromatography/Mass Spectrometry

ECS J. Solid State Sci. Technol.

Nakagomi

2015

An experimental method for evaluating the intensity of molecular interactions between organic molecules and surfaces was studied. The organic compounds' physisorption and desorption rates to and from the silicon native oxide surface were in situ measured using a quartz crystal microbalance and analyzed following the multicomponent organic species adsorption-induced contamination model. Three organic compounds, isopropanol, octanol and diethylphthalate, in each single-component system and in a multicomponent system were used in dry and humid atmosphere. The physisorption and desorption rate constants of these compounds in the dry atmosphere were higher than those in the humid atmosphere. However, the molecular radii in both atmospheres were similar. Thus, the interaction between the organic molecules and the surface was influenced by the existence of a thin water layer, while the interaction between the organic molecules had less influence by the atmosphere. Preparing an appropriate material surface 1-7 is very often a critical operation for producing specific functions at and on the surface. Actually, because various kinds of molecules, organic and inorganic, are adsorbed at the surface and remain there, often as surface contaminations, their behavior should be studied for removing them by any cleaning methods.Generally, the surface cleaning process consisted of operations utilizing various molecular interactions including physisorption and desorption. Their elemental surface processes are the occupation of a molecule's own area with attraction and repulsion. Additionally, the critical surface contamination for manufacturing the advanced electronic devices is very often at a molecular level. 7 Thus, these molecular interactions should be individually evaluated in order to choose and design the optimum surface preparation process. For this evaluation, a very sensitive and easy measurement method is expected.For this purpose, the quartz crystal microbalance (QCM) 8 is expected to have a significant potential, because it has a very low detection limit in the ng/cm 2 range, which can detect the molecular layer formation, such as airborne molecular contamination. Additionally, by linking it with the rate theory, such as the multicomponent organic species adsorption-induced contamination (MOSAIC) model, 9-15 the molecular radii of the organic molecules can be evaluated along with the rate parameters of physisorption and desorption. Additionally, this analysis could determine the molecular radii and their summation at the surface for showing the attraction and repulsion between the molecules in a multicomponent system.In our previous study, 14 the multicomponent organic compounds' physisorption and desorption were evaluated in detail in a humid atmosphere corresponding to that in a clean room for manufacturing advanced semiconductor materials and devices. For the three organic compound systems consisting of isopropanol, octanol and diethylphthalate, the interaction between these organic molecules were shown to be at an...

Section: Methodsmentioning

confidence: 98%

“…The water molecules are physisorbed on the native oxide surface and form a thin water layer. 6 Finally, the organic molecules are physisorbed there. Fig.…”

Section: -14mentioning

confidence: 99%

Evaluation of Molecular Interaction between Organic Molecules Physisorbed on Silicon Native Oxide Surface in Dry and Humid Atmosphere

ECS J. Solid State Sci. Technol.

Nakagomi

2015

“…Various kinds of chemical compounds existing in the ambient atmosphere, such as acids, bases, organic compounds, inorganic compounds, and metals, can adsorb at the material surface [1][2][3][4][5][6][7][8]. This potentially multiple-component contamination is a fundamental problem in many industrial processes that use or produce highly clean surfaces, such as wet cleaning, lithography, etc.…”

Section: Introductionmentioning

confidence: 99%

“…In those systems containing humidity, hydrophilic compounds, such as acids, tend to be contained in the water film produced by water vapor [6], while organic compounds can remain at the water film surface. Thus, a facile and simple process should be developed to identify the layer where the chemical compounds prevail.…”

Section: Introductionmentioning

confidence: 99%

Molecular Adsorption and Desorption Behavior on Silicon Surface in a Complex Ambient Atmosphere Containing Vapors of Diethylphthalate, Acetic Acid and Water

Ono²,

Sakurai³

et al. 2013

AJAC

Using a complex ambient atmosphere containing vapors of an organic compound, acid and water, the molecular adsorption and desorption behavior on a silicon surface was studied using the in-situ measurement of a quartz crystal microbalance linked to the rate theory. Because the behavior of diethylphthalate (DEP) could be reproduced assuming a single-component system, acetic acid (ACA) and DEP are concluded to separately exist in the water film and at the water film surface, respectively. This conclusion was obtained from both the adsorption and desorption behaviors. The process developed in this study is useful for determining the layer in which chemical compounds are present.

“…The material surface condition prepared in such an environment very often governs the final product quality including various functions present on the surface. [1][2][3][4][5][6][7] In order to achieve a desirable surface condition, the adsorption behavior of various compounds should be clarified. Particularly, the combination of compounds interacting with each other should be found by means of a simple and easy method.…”

mentioning

confidence: 99%

In Situ Method for Determining Combination of Organic Compounds Interacting with Each Other on Silicon Oxide Surface

Choi

ECS J. Solid State Sci. Technol.

2015

An experimental process for determining a combination of organic compounds, interacting with each other on a silicon oxide surface, was developed using a quartz crystal microbalance. The surface concentration of the four organic compounds, such as L-menthone (Mth), decylacetate (DA), diethylphthalate (DEP) and octanol (OCT), on a silicon oxide surface was evaluated in multi-component systems. The increase and decrease in the surface concentrations were not reversible with the changing gas phase concentrations in the two-component system consisting of Mth and DEP. Additionally, the small droplet shape of Mth placed on the DEP-coated glass plate surface was significantly different from that of DEP on the Mth-coated surface. Based on these results, Mth and DEP molecules were considered to have a significant interaction with each other. In any environment for industrial production and academic research, various kinds and amounts of organic and inorganic molecules are transported and adsorbed on a material surface in a multicomponent system. The material surface condition prepared in such an environment very often governs the final product quality including various functions present on the surface. [1][2][3][4][5][6][7] In order to achieve a desirable surface condition, the adsorption behavior of various compounds should be clarified. Particularly, the combination of compounds interacting with each other should be found by means of a simple and easy method.For this purpose, the molecular behaviors in single-component and multi-component systems have been studied by taking into account the physisorption and desorption rates using the quartz crystal microbalance (QCM). 8 The information obtained by the QCM could be understood by using the Multi-Component Organic Species Adsorption-Induced Contamination (MOSAIC) model in our previous studies 9-16 using isopropanol (IPA), octanol (OCT) and diethylphthalate (DEP). In previous studies, 13-16 the molecular interaction was found to be not significant among the IPA, OCT and DEP. These studies were based on the difference in the area occupied by the organic molecule in a multi-component system from that in a singlecomponent system. In order to show the capability for finding the existence of a molecular interaction, other organic molecules having various molecular structures should be evaluated. Additionally, the process for the measurement and the analysis should be simple and easy.For this purpose, organic compounds having characteristic shapes, such as L-menthone (Mth) and decylacetate (DA), are expected. DA has an asymmetric structure consisting of a long carbon chain and oxygen. Mth also has an asymmetric shape with cyclohexane and oxygen. The oxygens in both Mth and DA are expected to have a steric hindrance when being adsorbed on the silicon oxide surface, different from IPA, OCT and DEP. Additionally, for easily finding the existence of an interaction between various compounds, a simple process should be developed; the obtained conclusions are expected to be consistent...