Polymer spin coating process

Fig. 8.7 Fabrication sequence of a polymer microring resonator (a) prepare a nanoimprint mold (b) spin coat a polymer thin film (c) perform nanoimprinting process (d) separate the sample from the mold (e) dry etch the residual layer (f) create pedestals by wet etch...

Different approaches to obtain wrinkles in thin polymer sheets were presented by Harrison and Stafford [53, 54], Thin polyethylene (PE) sheets were first spin-coated onto silicon wafers and subsequently transferred to a relatively thick slab of PDMS by releasing the film in water. This technique takes advantage of the tunable film thickness by the spin-coating process (spin velocity, concentration of polymer solution) as well as the water-insoluble nature of PE. Wrinkles were induced by either compressing the PDMS-PE-bilayer setup [54] or depositing the PE-sheet onto a prestrained PDMS slab and releasing the strain afterwards [53],... 

All sensitive layers were prepared from solutions of Makrolon in mixtures of chloroform and dichlorobenzene by a spin-coating process. By adjustment of the rotation speed and time the thickness of the layers were varied between 35 nm and 455 nm. Layer thicknesses and refractive indices were determined by spectral ellipsometry. Furthermore the polymer thicknesses were verified by a surface profilometer (Alpha Step 500, Tencor Instruments, Mountain View, USA). 

Processable conjugated polymers can readily be incorporated into electronic devices through the spin-coating process. The devices that have attracted most attention are field effect transistors (FETs) and thin film diodes, the latter primarily as light emitting diodes (LEDs). Typical structures are shown in Fig. 9.28. 

The Morphology Control of Polymer Thin Films via the Spin-Coating Process... 

The film formation in fhe spin-coating process for the polymer/fuller-ene blend system in the mixture solvent is a complex process because it is a nonequilibrium state that both thermodynamic and kinetic parameters can influence phase separation, and the system contains four components with dissimilar physical/chemical properties. We found the donor/acceptor components in the active layer can phase separate into an optimum morphology during the spin-coating process with the additive. Supported by AFM, TEM, and X-ray photoelectron spectroscopy (XPS) results, a model as well as a selection rule for the additive solvent, and identified relevant parameters for the additive are proposed. The model is further validated by discovering other two additives to show the ability to improve polymer solar cell performance as well. 

We anticipate that the entanglement density in the dry spin-coated films is lower than in an equilibrated bulk system. Such a departure fi om equilibrium most likely generates residual stresses. As one consequence, we tentatively attribute the observed hole nucleation, which initiated the dewetting process of holes, to the presence of such residual stresses within the film [165]. In this way, rupture can be related to the spin-coating process used to prepare thin polymer films. 

Figure 7.4 A schematic model describing the owing to solvent evaporation only. The interface film formation during the spin coating process, between the polymers destabilizes (iv) and the After the initial spin-off stage where both film phase separates laterally (v, vi).

Second exposure (A,) Expose photoresist (UV, mask) Wet process photoresist Plasma etch Strip photoresist Spin coat NLO polymer Spin coat top cladding layer... 

---