Application of zeolite-like silica nano-particles in anti-corrosion films and in low-k films
Date Issued
2015
Date
2015
Author(s)
Lin, Guan-Ye
Abstract
The applications of MFI-like and BEA-like nano-particles in anti-corrosion films and in low-k films were studied. For anti-corrosion application, the particles were added in GPTMS-TEOS (3-glycidoxypropyltrimethoxysilane and tetraethyl orthosilicate) solution to form an organic-inorganic anti-corrosion coating solution. It was expected that the hydroxyl groups on nano-particles surface can form chemical bonds with those of GPTMS through dehydration reaction, so that a better anti-corrosion property can be generated. It has been found from the research results that heat treatment of the resulting organic-inorganic films with the addition of MFI-like particles is an important factor to increase anti-corrosion property. Increasing stirring and mixing time of coating solution after the addition of nano-particles can also increase anti-corrosion of the films, which are heat treated at 130 ℃; Nevertheless, they cannot increase anti-corrosion significantly at higher film treatment temperatures. However, the stirring and mixing time can cause substantial difference of the films added with BEA-like particles. The viscosity of the coating solution, the thickness and the roughness of the resulting films all decreased with the increase of mixing time. Moreover, films anti-corrosion also decreased slightly with the increase of mixing time. The measurements of contact angle showed that the organic-inorganic films made in this research were hydrophilic. HMDS (hexamethyldisilazane) for surface modification and CF3CH2OH for modifying film property were applied respectively for improving hydrophobic property. It has been found that after films surface was modified by using HMDS, both hydrophobic and anti-corrosion properties can be increased. However, for the films with higher roughness and with GPTMS aggregation on the surface, the improvement is slight, because less hydroxyl group on the surface can be used for the HMDS modification. On the other hand, the addition of CF3CH2OH in the coating solution can also increase the resulting films hydrophobicity. Nevertheless, films thickness and hardness were deteriorated at the same time. For those added with MFI nanoparticles, the anti-corrosion property was increased. However, for those with BEA nanoparticles, the anti-corrosion was decreased due to the dramatic decrease of film thickness. It has been concluded from this study that the addition of MFI-like or BEA-like particles in GPTMS-TEOS solution would decrease anti-corrosion property of the films. The reason is that there are tetrapropylammonium hydroxide in MFI-like particles and tetraethylammonium hydroxide in BEA-like particles. After the addition of the particles, nitric acid in GPTMS-TEOS solution can react with those ammonium hydroxides to form salts in coating solution. The presence of salts in the films decreases hydrophobic property and anti-corrosion properties; moreover, may cause the cracks in the films. For the study of applications in low dielectric films, MFI-like colloid was used for preparation of porous low dielectric (low-k) films, which possess not only a k value below 2 but also a high mechanical strength. The effect of environmental humidity during low-k films processing and the effect of coating solutions made from different wall thicknesses of autoclaves on properties of low-k films were investigated. It has been found that environmental humidity can give negative influence on k values of the resulting films. It can be simply improved by using a hot plate as a heat source to lower the humidity during films processing. This approach can also accelerate HF etching rate on the films for the later films properties measurements. On the other hand, in spite that silica nanoparticles made by thin-wall autoclave were larger than the thick one, there was no influence on low-k films’ properties. Both were able to possess not only a k value below 2 but also a high mechanical strength.
Subjects
Anti-corrosion films
Inorganic-organic hybrid films
Contact angle
Silica
Tetraethylammonium hydroxide (TEAOH)
Tetrapropylammonium hydroxide (TPAOH)
low dielectric films
humidity
Type
thesis
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