應用氧化矽奈米粒製備抗腐蝕膜及低介電薄膜

Abstract

本研究應用MFI-like或BEA-like二氧化矽奈米顆粒懸浮液(colloid)於研發抗腐蝕膜及低介電薄膜。 有關抗腐蝕膜研究方面，是添加二氧化矽奈米顆粒至GPTMS-TEOS(3-glycidoxypropyltrimethoxysilane and tetraethyl orthosilicate )鍍膜液中，以製備有機-無機混成抗腐蝕膜，期望藉由奈米顆粒表面Si-OH與GPTMS或矽烷(TEOS)水解後產生之Si-OH脫水縮合形成結構更緻密之膜。本研究已藉由增加鍍液攪拌時間、以及提升膜熱處理溫度探討添加顆粒後對抗腐蝕性及縮合程度的影響。除此之外，已利用HMDS (hexamethyldisilazane)表面修飾以及添加CF3CH2OH以提升膜之疏水性，藉由疏水基之增加而提升抗腐蝕性。研究結果發現添加MFI-like顆粒並鍍膜後，用來增加縮合反應的熱處理溫度是提升薄膜抗腐蝕性的重要關鍵。雖然鍍液攪拌時間增長，在膜熱處理溫度低時能改善薄膜之抗腐蝕性，但在熱處理溫度高時則無明顯影響，。而添加BEA-like顆粒後，隨鍍液攪拌時間增長，溶液黏度及鍍膜厚度都下降，且膜表面由粗糙轉為光滑平坦，抗腐蝕力卻些微下降。本研究藉由接觸角量測得知，各有機-無機混成抗腐蝕薄膜均具親水性，較不符抗腐蝕膜要求，因此行疏水性質改良。經HMDS表面修飾後，發現能提升疏水性及膜的抗腐蝕力，但較粗糙的膜因疏水性GPTMS凸塊形成於表面，能修飾之位置相對較少，因此修飾效果較差。有機-無機混成鍍液中添加CF3CH2OH以做性質修飾，所成的膜雖然疏水性能增加，但膜厚及硬度都會降低。不過對添加MFI-like顆粒薄膜的抗腐蝕力仍舊能提升，但對添加BEA-like顆粒的薄膜則因膜厚過於降低，而使抗腐蝕力不增反減。 本研究已結論出，添加MFI-like或BEA-like奈米顆粒於GPTMS-TEOS所成薄膜比不添加的，其抗腐蝕力要來得差。已由實驗證實，本研究添加奈米顆粒的方式會使顆粒中有機氨模板與GPTMS-TEOS鍍液中硝酸液反應產生鹽類，因而減弱薄膜抗腐蝕力，甚至使膜表面產生裂紋及裂縫造成硬度下降。未來應嘗試製備不含有機氨模板之奈米顆粒，以便進一步驗證相關奈米顆粒對抗腐蝕性影響。 有關研究低介電薄膜方面，是直接應用MFI-like二氧化矽奈米懸浮液為鍍膜液，製備介電係數小於2且高機械強度之孔洞型低介電薄膜。是探討製程中環境濕度，以及兩不同壁厚高壓釜所製備不同大小奈米粒，對低介電薄膜性質影響。 研究結果發現，環境濕度與k值呈正比相關。為降低濕度造成k值上升問題，利用加熱板提供熱源降低環境濕度，已可降低濕度約10%，並且加快HF蝕刻二氧化矽之速率，減少樣品暴露於空氣之時間，而有效降低薄膜介電值。另外發現，不同壁厚高壓釜會製備出不同大小奈米粒，但對低介電薄膜性質並無影響，皆可製備出介電係數小於2且高機械強度之孔洞型低介電薄膜。

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.