Properties positive photoresists

Miscellaneous Applications. PEIs and their derivatives ate used as cementation auxihaties in cmde oil exploration (459), and for breaking cmde oil emulsions (460) in cmde oil extraction. Seed coatings of water-soluble copolymers containing polyethyleneimine have been developed (461). Polyethyleneimine derivatives have positive photoresist properties (462) amidated polyethyleneimines improve the flow properties of cement (463) and with few exceptions, A/-acyla2iddines act as chemical sterilisers for insects (464). 

The synthesis and electrochemical properties of carbon films prepared from positive photoresist have been reported.The initial direction for this work was the fabrication of carbon interdigitated electrodes. In this work, positive photoresist was spin coated on a silicon substrate, patterned by photolithography, and pyrolyzed to form the carbon electrode. In more recent work, laser excitation has been used to both pyrolyze the film and to write the electrode pattern. ... 

Table III. Properties of Selected Deep UV Positive Photoresists...

Chemical nature of photoresists, the chemistries involved in the photolithography, the properties of photoresists are briefly described. The discussion includes diazonaphthoquinone/novolac positive photoresists, polymer-aromatic diazide negative photoresists, photopolymerizable compositions, chalcogenide glass using systems, chemically amplified photoresists, and photoresists with an image formation in a thin layer. 

Sensitivity, S, to the UV radiation seems to be one of the most important properties of a photoresist. The value can be defined as dose (or exposure) of the UV light necessary to turn a photoresist into either insoluble (negative photoresist) or soluble (positive photoresist) compound. 

These polymers are soluble in spin-coating solvents, show good film-forming and coating properties, provide excellent adhesion to most substrates, and exhibit enough balance in the needed binder properties to be used almost exclusively in all commercial DNS containing positive photoresist formulations. 

In order to get reproducible lithographic results in any production process, it is important that the fmictional properties of the applied photoresist be kept constant from one to the other lot. Obviously, the functional properties of a resist are correlated with its physical properties. In this section, some of these correlations will be discussed for both negative and positive photoresists. Finally, some speciality polymers for miscellaneous applications will be described. 

As negative photoresists based on the above-mentioned polymers exhibit serious swelling during development, their resolution is limited to approximately 5 pm. Therefore, some negative resist formulations based on novolak have been developed recently As novolak is mostly used in positive photoresists, the properties of this resin are discussed in the next section. 

In order to improve the properties of the implanted PPP, broadening the profile concentration and moving the ions close to the surface was attempted and partially achieved by carrying out implantation through a positive photoresist whose thickness decreases during the irradiation [253b]. Compared to other chemical and electrochemical doping processes which can be considered as reversible, since the dopant species out-diffuse very easily when the material is placed in air, the implanted PPPs appear to be more stable, probably because the doped layers are buried but also because the sites where the ions are implanted correspond to dense and crystalline areas which prevent their out-diffusion [253]. 

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