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Photoresist SU8 CrossLinking
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=8zTeZAVYWXM
More details: http://sites.google.com/site/lergutie... • The SU-8 is a negative, epoxy-type, near-UV photoresist (365 nm). This photoresist can be as thick as 2 mm and aspect ratios up to 25 have been demonstrated with a standard UV-lithography. • Photoresists such as the SU8, are based on epoxies. The term epoxy is a prefix referring to a bridge consisting of an oxygen atom bonded to two other atoms, very often carbon, already united in some way. Such a structure is called 1,2-epoxide. http://ler.gutierrez.googlepages.com/... • An epoxy resin is defined as a molecule containing one or more 1,2-epoxy groups.Such molecules are capable of being converted to a thermoset form or three-dimensional network structure. This process is called curing or crosslinking. • The term curing or crosslinking is used to describe the process by which one or more kinds of reactants, i.e., an epoxide and a curing agent, are transformed from a low-molecular-weight material to a highly crosslinked network. • Photoepoxies, such as the SU8, are normally polymerized by a cationic photopolymerization. • Cationic polymerization is induced by Lewis acids. The general mechanism is represented at figure 3.1. The Lewis acid is generated during UV illumination. The polymerization is done by the ring-opening of the 1,2-epoxy. • The SU8 photoresist is an epoxy based photoresist. The main part is the EPON SU8 epoxy from Shell Chemicals. It is a highly functionalized molecule with 8 epoxy groups. The polymerisation is done by a cationinc photopolymerization mechanism (see http://ler.gutierrez.googlepages.com/....
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