Papers by Keyword: Fluoropolymer

Abstract: Semi-crystalline polymers such as fluoropolymers are extremely difficult to coat with using solid-state deposition technique such as cold spray (CS) due to its high viscoelastic-viscoplastic behavior. Generally, fluoropolymers solid-state deposition using CS are characterized by a relatively low deposition efficiency (DE) as compared to metallic materials using this deposition technique. In this article, the study on the effect of hydrophobic fumed nanosilica (FNS) and fumed nanoalumina (FNA) in Perfluoroalkoxy (PFA) solid-state deposition using CS has been studied. This study incorporated certain parameters related to the CS process. In addition, powder modification technique using hydrophobic FNS and FNA as additive to feedstock has been studied as well. The results show a number of parameters affected the DE; particle size, traverse speed, gas temperature, and addition of hydrophobic fumed nanoparticles, indicated a better DE. Moreover, PFA coating produced in this manner, retained its hydrophobicity.

Abstract: In this paper we demonstrate an effective process control mechanism to significantly improve on the process performance of a BEOL post-etch cleaning process with an integrated partial or complete removal of the TiN HM (hard mask) layer by so called formulated chemistries on a single wafer processing tool. The novel process control mechanism enables a 50% reduction in chemical consumption while achieving an at least equivalent TiN etch uniformity.

Abstract: In this paper, we consider the possibility of using, in friction pendulum bearings, multilayer friction proof coatings based on polytetrafluoroethylene compounds modified by nanoscale spinels such as magnesium, zinc and chromium. The tribological effect of applying the coating is achieved by formation of a friction transfer layer. For better wear resistance, we applied a multilayer coating with a power frame covered using electrospark coating. We performed an experimental research of bushing samples and various coating fluoroplastic bases. The research on a friction machine “SMT-1” has shown the effectiveness of epoxy fluoroplastic composition as an anti-friction coating in comparison to other types of fluoropolymer bases.

Abstract: Thermal stability can reflect the thermal degradation speed of polymers during the melt processing. In this paper, we used Kissinger, Flynn-Wall-Ozawa and Coats-Redfern method to study the kinetics of non-isothermal degradation of PFA. The thermal degradation activation energy obtained from the Kissinger method, Flynn-Wall-Ozawa method and Coats-Redfern method is 228.5 kJ/mol, 213.9 kJ/mol and 237.4 kJ/mol respectively. The Flynn-Wall-Ozawa method indicates the thermal degradation reaction PFA is a secondary reaction.

Abstract: Back end of the line processing requires removal of deposited polymers resulting from etch processes. These polymers typically exist on the whole of the pattern including the dielectric sidewalls and can be removed by wet cleans or a combination of wet cleans and plasma treatments. When a porous dielectric is present these residues cannot be efficiently removed using plasma or certain wet cleans without potentially damaging the underlying porous dielectric layer. Therefore there exists a need for a one-step wet clean that can completely remove the residues without damaging the porous dielectric. Previous work has shown that a combination of a UV pretreatment followed by a wet clean can remove these residues [1]. These residues are composed of CF, -CF₂, and CF₃ groups as described by X-ray photoelectron spectroscopy (XPS). In an effort to improve the manufacturing viability of such a process we have undertaken a study to develop a one-step wet clean for fluoropolymer removal. Utilizing a blanket checkerboard pattern with a model fluoropolymer deposited on a porous low-κ substrate we have demonstrated the one-step wet clean of the aforementioned fluoropolymer while maintaining compatibility with the pristine and etch processed porous low-k dielectric.

Abstract: We demonstrated high adhesive fluoropolymer/copper interface through combination of atmospheric pressure plasma with liquid phase self-assembly. However, there are some disadvantages in atmospheric pressure plasma technique, such as small processing area due to the localized plasma and high gas temperature. Medium pressure plasma process has some advantages over atmospheric pressure plasma systems. A large plasma volume and low gas temperature, available for surface treatment of polymer material, can be easier obtained at medium pressure than at atmospheric pressure, which can result in a higher overall productivity. In this paper, we investigated the adhesion strength of electroless copper plated layer formed on poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) surface modified by combination of medium pressure helium plasma irradiation and aminated acrylic polymer grafting. The 90° peel test result for copper plating film formed on the treated PFA films showed the adhesion strength of 0.44 N/mm without increasing the surface roughness.

Abstract: Laminated fluoropolymer films with regular void structure, fabricated by using a process consisting of the patterning and fusion bonding steps, are polarized to be piezoelectric. The influence of the applied voltage on the piezoelectric d₃₃ coefficient is investigated. The measurements of ferroelectric-like polarization-voltage hysteresis loops are taken to further understand the capability of polarization in the laminated films. The compressive Young’s moduli of the films are determined from the dielectric resonance spectra. The results show that the laminated fluoropolymer films are piezoelectric after proper charging. The maximum d₃₃ coefficients of the five-layer laminated piezoelectrets are achieved at the applied voltage of 5 kV. The remnant charge density of 0.3 mC/m² is obtained from the polarization-voltage hysteresis loop at a bias voltage of 4 kV. The measured anti-resonance frequency and calculated compressive Young’s modulus for the five-layer laminated films are 112 kHz and 0.48 MPa, respectively.

Abstract: Glass and glazes are easy-to-clean surfaces often used in everyday environments where the surface needs to repel soils and deposits. In general, these surfaces have good chemical durability in everyday environments. However, the durability is rapidly degraded in solutions of high or low pH. This kind of surface corrosion has been found to diminish the cleanability. Surface topography has also a certain influence on the soil attachment and cleanability. Self-cleaning and easy-to-clean coatings have been employed to enhance the cleanability of surfaces. In this report surface properties of three coatings reported to enhance the cleanability of glass and glazed surfaces are summarized. The properties discussed are the surface appearance, roughness, wettability, soil attachment and soil removal. Also the chemical and mechanical durability of the coatings are discussed. The coatings studied were a commercial fluoropolymer film applied at room temperature, an experimental sol-gel derived TiO2 coating calcined at 500°C, and an experimental liquid flame sprayed TiO2-Ag coating applied on the substrates at 500-800°C. The advantages of the fluoropolymer coating are easy application and soil good soil repellence, but the coating has limited chemical and mechanical durability. The manufacture of the sol-gel TiO2 coating requires several processing steps. The coated surface showed excellent cleanability, and good chemical and mechanical durability. The liquid flame sprayed coating has potential to be applied online in the material manufacture. However, the processing parameters should be optimized in order to achieve desired improvements in the cleanability.

Abstract: The interaction between photo resist and highly polymerizing dry etch chemistries results in the deposition of fluoropolymers on the bevel and edge of silicon wafers. These polymers are inert to most aqueous processing chemicals, but exposure to HF lifts these polymers off the bevel. This results in migration of defects to the face of the wafers. The defects are generally found within 50mm from the edge of the wafer.

Abstract: The goal of this work was to establish the compatibility of mat glazes with functional films known to render the surfaces with self-cleaning or easy-to-clean properties. Glazes with wollastonite, pseudowollastonite, diopside and zircon as the main crystalline phases in the surfaces were coated with fluoropolymer as well as ceramic, sol-gel derived titania and zirconia films. The glazes were soaked in typical detergent solutions used in everyday life up to four days. The surface roughness was measured with confocal optical microscope and the surface was imaged and analyzed with SEM/EDXA. When applied on wollastonite and pseudowollastonite containing glazes the functional films readily reacted in water solutions by pitting of the surface in the vicinity of the crystals. The ceramic titania and zirconia films showed better chemical resistance on wollastonite –free glazes, while the fluoropolymer film corroded in the most alkaline environments. The results indicate that functional films could be used also on rough surfaces without markedly affecting the surface topography. However, the films should be applied only on glazes with an excellent chemical resistance.