Deposition spin-coating

Thin solid films of polymeric materials used in various microelectronic applications are usually commercially produced the spin coating deposition (SCD) process. This paper reports on a comprehensive theoretical study of the fundamental physical mechanisms of polymer thin film formation onto substrates by the SCD process. A mathematical model was used to predict the film thickness and film thickness uniformity as well as the effects of rheological properties, solvent evaporation, substrate surface topography and planarization phenomena. A theoretical expression is shown to provide a universal dimensionless correlation of dry film thickness data in terms of initial viscosity, angular speed, initial volume dispensed, time and two solvent evaporation parameters. 

Spin coating deposition (SCD) is the primary commercial process for forming thin films of the various polymeric materials used in the electronics industry. Yet, very little is known about the fundamental physical processes of polymer thin film formation on... 

Souza FL, Lopes KP, Nascente PAP, Leite ER (2009) Nanostructured hematite thin Aims produced by spin coating deposition solution application in water splitting. Sol Energy Mater Sol C 93 362-368... 

An AFM study of the topology of polymer spin-coated depositions of Glu-containing ELPs, from acid and basic solutions, on a Si hydrophobic substrate at temperatures below Tt has shown that in acidic conditions, the polymer deposition just shows a flat surface without particular topological features (Fig. 10a). 

However, the most frequent way to obtain a CIME consists in the formatiOTi of a film coating. Different deposition procedures can be followed depending oti the thickness required. Among others, evaporation of the solvent from a clay aqueous suspension is the simplest and most widely used method for film thickness ranging from a few hundreds of nanometers to several micrometers. In order to obtain a more homogeneous, reproducible, and thinner film, a spin coating deposition technique is also adopted. Due to the poor stability of clay films obtained by these methods, alternative approaches imply the entrapment of clay particles into polymeric membranes [39—41], epoxy resin [40], or sol-gel structure [42]. 

Bunn CW, Alcock TC (1945) The texture of polyethylene. Trans Faraday Soc 41 317-325 Cardoso VF, Minas G, Lanceros-Mendez S (2012) Multilayer spin-coating deposition of poly (vinylidene fluoride) films for controlling thickness and piezoelectric response. Sens Actuators A Phys 192 76-80... 

Figure 9.4 Examples of complex systems obtained from spin coating deposition, (a) Hybrid TiOj/PHEMA-co-PGMA [34] and (b) Si02A/V03 nanoparticle [35] based 1D Bragg reflectors. Hybrid spin-coated resist patterned...

This characteristic of RAIR can be observed experimentally. Fig. 8 shows the transmission spectrum of polydimethylsiloxane (PDMS) while Fig. 9 shows the RAIR spectrum of a thin film of PDMS spin-coated onto a chromium substrate. It can be observed that the bands near 1024 and 1095 cm have similar intensities in the transmission spectra but the band at higher frequencies is clearly much more intense in the RAIR spectrum. This change in relative intensity when PDMS is deposited onto a reflecting substrate is related to optical effects and is not related to orientation effects. 

Organic coatings are also possible. The classic example is the paralene process where a cyclic dimer of p-xylene is thermally decomposed at about 850°C to form /i-xylene free radicals that polymerize into a conformal film when deposited on a solid surface. Other examples of polymerization from a deposited vapor have been developed, and advocates believe that this technology will replace spin coating of silicon wafers. 

Figure 4.30. AFM images of rhodium particles deposited by spin-coating impregnation on flat Si02 on a Si(lOO) substrate particle, after reduction in hydrogen. [Adapted from...

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