Specific Process Knowledge/Lithography/Pretreatment: Difference between revisions
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Pretreatment, also known as ''priming'', is done before spin coating in order to ensure the best conditions for adhesion between the substrate surface and the resist. Pretreatment ranges from a simple dehydration bake over etching the native oxide to vapor phase deposition of an adhesion promoter. The goal of pretreatment is to remove any moisture that may be adsorbed on the surface of the substrate, and/or to modify the contact angle of the surface to match that of the resist to be coated on the substrate. | Pretreatment, also known as ''priming'', is done before spin coating in order to ensure the best conditions for adhesion between the substrate surface and the resist. Pretreatment ranges from a simple dehydration bake over etching the native oxide to vapor phase deposition of an adhesion promoter. The goal of pretreatment is to remove any moisture that may be adsorbed on the surface of the substrate, and/or to modify the contact angle of the surface to match that of the resist to be coated on the substrate. | ||
All surfaces can be divided to hydrophilic or hydrophobic surfaces. Oxidized surfaces such as SiO<sub>2</sub> or surfaces with native oxide (e.g. Si or Al substrates) are considered to be hydrophilic and have very bad wetting with hydrophobic resist. The adhesion of most resists on hydrophilic surfaces is deteriorated if moisture is present on the surface. Therefore it is very important to do the pretreatment step before | All surfaces can be divided to hydrophilic or hydrophobic surfaces. Oxidized surfaces such as SiO<sub>2</sub> or surfaces with native oxide (e.g. Si or Al substrates) are considered to be hydrophilic and have very bad wetting with hydrophobic resist. The adhesion of most resists on hydrophilic surfaces is deteriorated if moisture is present on the surface. Therefore it is very important to do the pretreatment step before spin coating. This page gives an overview of treatments available at DTU Nanolab to promote photoresist adhesion. | ||
'''Dehydration:''' | '''Dehydration:''' | ||