Photoablation process

The photoablation process consists of the absorption of a short-wavelength laser pulse to break covalent bonds in polymer molecules and eject decomposed polymer fragments. Channels of various geometries and dimensions can be obtained using an appropriate mask. Many commercially available polymers can be photoablated, including polycarbonate, poly(methyl methacrylate) (PMMA), polystyrene, nitrocellulose, poly(ethylene terphtalate) (PET), and poly(tetrafluoroethylene) (Teflon). ... 

Photoablation Process by which short-wave-length laser light breaks molecular bonds in matter and causes material to be ejected from the surface with very little heating of the sample. 

PhoStrip process, as advanced wastewater treatment, 25 907 Photoablation, 20 278 Photoacid generators (PAGs), 10 521 ... 

Microfabrication by means of laser radiation covers a wide range of different methods (24,25). On the one hand, these are processes where material is removed in an intense electromagnetic field by melting, evaporation, decomposition, photoablation, or a combination of these phenomena. On the other hand, generating processes exist where structures are built up from liquid resins, laminated layers, or powders using, e.g., photochemically induced crosslinking of organic compounds... 

Photoablation of Copolymers, Other workers have also investigated the phenomenon of polysilane self-development. Zeigler and co-workers (13) have studied the self-development of a number of polysilane homo- and copolymers and found that self-development eflSciencies increase with the size of substituents. They also suggested that the material removal process for alkyl-substituted poly silanes at low fluences (<50 mj/cm per pulse) is predominantly photochemical rather than photothermal. By using a 1 1 copolymer, poly(methyl-n-propylsilane-co-isopropylmethylsilane), images were generated by excimer laser exposure at 248 nm. 

The absence of heat deposited below 1.5 times the penetration depth may help to explain the cold etching process in far U V photoablation as used commercially in the corrective eye surgery, LASIK. 

There are several ways (see Fig. 5) in which polyimides have been used in applications where photoimaging is required to produce a pattern on a substrate (typically silicon, or other materials including polyimide itself) (205). The first method is reactive ion etching (RIE) (includes plasma etching) or photoablation. This method does not require a photosensitive material, only a mask that can withstand the reactive ion gas or photons, and the material to be patterned, which is protected by the mask. In RIE, the reactive ions, generated by an RF field, attack the exposed polyimide to etch out the pattern of the mask. This process can be used with conventional polyimide film and requires few steps, but is not highly accurate and requires a hard (metal, silicon, etc) mask. The other methods... 

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