Polymers in Photoresist Applications

In this chapter, attention is focused on a number of polymers that are either themselves characterized by special properties or are modified for special uses. These include high-temperature and fire-resistant polymers, electroactive polymers, polymer electrolytes, liquid crystal polymers (LCPs), polymers in photoresist applications, ionic polymers, and polymers as reagent carriers and catalyst supports. 

ROMP POLYMERS IN ELECTRONIC APPLICATIONS CONJUGATED POLYMERS, POLYELECTROLYTES AND PHOTORESIST POLYMERS... 

For the application of polymers in electronic applications one has to consider the various tasks polymers can fulfil in the world of electronics. In this article we do not want to talk further about this kind of application with the only exception of photoresists, which play an important role in microelectronics. 

After having discussed the photochemistry involved in a number of photoresists and their technological applications, we will consider in some more detail the role of polymers in photoresist systems. The most familiar polymers in photoresist are poly(vinyl alcohol), poly(vinyl cinnamate), poly(isoprene) and novolak. These resins are manufactured on an industrial scale according to general procedures, but the exact conditions, applied in the production process are mainly proprietary to the manufacturers. 

An alternative strategy is to deposit a positive photoresist to mask areas where electrode material is to be absent. Upon exposure through the mask and development, the base substrate will be exposed where the electrode components are to be deposited. The electrode materials are then typically deposited over both the bare substrate and the photoresist. A liftoff procedure is then used to remove both the photoresist and excess deposited electrode film material by swelling the photoresist polymer in a suitable solvent, leaving the electrode array behind [40,45,47] with the underlying substrate also exposed in regions where no electrode is present. Increasingly complex patterns of application of multiple... 

Polysilane high polymers possessing fully saturated all-silicon backbone have attracted remarkable attention recently because of their unique optoelectronic properties and their importance in possible applications as photoresists, photoconductors, polymerization initiators, nonlinear optical materials etc. A number of review articles have been published on this topic4-9. The studies in this field have stimulated both experimental and theoretical chemists to elaborate on understanding the excited state nature of polysilanes and oligosilanes and of their mechanistic photochemistry. 

The great value of the unique characteristics of fluorinated polymers in the development of modern industries has ensured an increasing technological interest since the discovery of the first fluoropolymer, poly(chlorotrifluoro-ethylene) in 1934. Hence, their fields of applications are numerous paints and coatings [10] (for metals [11], wood and leather [12], stone and optical fibers [13, 14]), textile finishings [15], novel elastomers [5, 6, 8], high performance resins, membranes [16, 17], functional materials (for photoresists and optical fibers), biomaterials [18], and thermostable polymers for aerospace. 

In addition to conventional photoresist polymers, Langmuir-Blodgett (LB) films and SAMs [79-81] have been used as resists in photolithography. In such applications, photochemical oxidation, cross-linking, or generation of reactive groups are used to transfer micropatterns from the photomask into the mono-layers [82-84]. 

Fabrication aids include such applications as photoresists, planarization layers in multi-level photoresist schemes, and as ion implant masl. In these applications, the polymer is applied to the wafer or substrate, is suitably cured and/or patterned, but is removed after use. 

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