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The purpose of this paper is to investigate the efficiencies of argon (Ar), oxygen (O₂) and O₂ followed by Ar (O₂→Ar) plasma treatments in terms of contaminant removal and wire bond interfacial adhesion improvement. The aim of this study is to resolve the “lifted ball bond” issue, which is one of the critical reliability checkpoints for light emitting diodes (LEDs) in automotive applications.

Ar, O₂ and O₂→Ar plasma treatments were applied to LED chip bond pad prior to wire bonding process with different treatment durations. Various surface characterization methods and contact angle measurement were then used to characterize the surface properties of these chip bond pads. To validate the improvements of Ar, O₂ and O₂→Ar plasma treatments to the wire bond interfacial adhesion, the chip bond pads were wire bonded and examined with a ball shear test. Moreover, the contact resistance of the wire bond interfaces was also measured by using four-point probe electrical measurements to complement the interfacial adhesion validation.

Surface characterization results show that O₂→Ar plasma treatment was able to remove the contaminant while maintaining relatively low oxygen impurity content on the bond pad surface after the treatment and was more effective as compared with the O₂ and Ar plasma treatments. However, O₂→Ar plasma treatment also simultaneously reduced high-polarity bonds on the chip bond pad, leading to a lower surface free energy than that with the O₂ plasma treatment. Ball shear test and contact resistance results showed that wire bond interfacial adhesion improvement after the O₂→Ar plasma treatment is lower than that with the O₂ plasma treatment, although it has the highest efficiency in surface contaminant removal.

To resolve “lifted ball bond” issue, optimization of plasma gas composition ratios and parameters for respective Ar and O₂ plasma treatments has been widely reported in many literatures; however, the O₂→Ar plasma treatment is still rarely focused. Moreover, the observation that wire bond interfacial adhesion improvement after O₂→Ar plasma treatment is lower than that with the O₂ plasma treatment although it has the highest efficiency in surface contaminant removal also has not been reported on similar studies elsewhere.

Peel adhesion of an epoxy filleting compound and Parylene C conformal coating to plasma treated, solder mask coated substrates and the apparent contact angle of water on the treated surfaces were evaluated. No significant improvement was achieved in the case of the epoxy filleting adhesive for most solder mask coatings studied. On the other hand, Parylene C peel adhesion significantly increased after substrates were treated with air plasma and reached the level of Silane coupling agent primed substrates. This was in contrast to the decrease in Parylene adhesion to argon plasma treated substrates in comparison with the non‐treated substrates. This was related to the oxygen functionalities created on the surfaces by the air plasma versus the ablative nature of the argon plasma. No clear correlation was found between peel strength and the water contact angle in the case of the epoxy adhesive, while for the Parylene conformal coating peel strength achieved its maximum value at the middle of the contact angle range which resulted from the pretreatments applied in this study. It is concluded that air plasma is a very efficient solder mask pretreatment for Parylene conformal coating that can replace Silane primer. Also, if a calibration curve is established for each solder mask‐adhesive and solder mask‐coating system, the apparent water contact angle can serve as a convenient quality control tool for printed circuit finishing processes.

In the field of research on the application of digital printing to textile materials, there are still many research issues that arise from the very demanding interaction of digital printing technology and the complex, heterogeneous surface system of textile materials. This is precisely why the area of pre-treatment of textile materials is in need of research, and the purpose of this research was to establish the level of influence of physical and chemical activation of the textile surface with plasma and the possibility of improving the quality of the print and colour reproduction.

The paper deals with the possibility of applying argon and oxygen cold low-pressure plasma in the processing of cellulose knitted fabrics, with the aim of improving the quality of the print and colour reproduction in digital pigment inkjet printing. The selected raw material samples were 100% raw cotton and lyocell. After plasma treatment, the samples were printed by digital ink jet printing with water-based pigment printing ink. An analysis of the micromorphological structure of untreated and plasma-treated samples before and after printing was carried out, and a comparative analysis of the colour of the printed elements was carried out depending on the pre-treatment.

The conducted research showed a positive influence of plasma pre-treatment on the coverage of the fibre surface with pigments, the uniformity of pigment distribution along the fibre surface and the uniformity of the distribution of the polymeric binder layer. This has a positive effect on colour reproduction. Also, certain improvements in colourfastness to washing were obtained.

Considering the complexity of the topic, although exhaustive, this research is not sufficient in itself, but opens up new questions and gives ideas for further research that must be carried out in this area.

Also, this kind of research contributes to the possibility of adopting the idea of industrial plasma transformation, as an ecologically sustainable functionalisation of textiles, which has not yet been established.

This research is certainly a contribution to the establishment of acceptable textile pre-treatment methods in the field of digital printing, as one of the key quality factors in digital textile printing (DTP). Considering the still large number of obstacles and unanswered questions encountered in the field of digital printing on textiles, this kind of research is a strong contribution to the understanding of the fundamental mechanisms of the complex interaction between printing ink and textile.

The purpose of this paper is to investigate plasma treatment for Tencel microfibre fabrics for possible improvement in various functional properties.

The plasma treated and untreated fabrics were dyed using reactive dyes and evaluated for comfort properties such as wicking, water vapour permeability and air permeability.

The various comfort properties of plasma treated and an untreated Tencel microfibre fabric have been studied. The wicking results showed a significant reduction in wicking time for plasma treated fabrics compared to untreated fabrics. The test results for water vapour permeability show no significant difference between plasma treated and untreated fabrics. The plasma treated samples show higher air permeability than untreated samples. In the wetting test, it is clearly seen that the plasma treated samples absorbed the water at a faster rate.

This research investigates plasma treatment for Tencel microfibre fabrics for possible improvement in various functional properties.

The purpose of this paper is to study the possibility and validity of using radio frequency (RF) power argon (AR) ion plasma treatment to modify the surface of nitrile butadiene rubber (NBR) and the change in the chemical structure under various bias voltage. Using wear test, the authors also compared the friction and wear properties of untreated and treated NBR.

The hybrid RF-power sputtering system was used to generate RF Ar plasma to modify the surface of NBR specimens. The tribological properties were evaluated by ball-on-disc test using a load cell mounted on the ball holder.

It was found that the NBR surface treated by the Ar plasma improved the wettability, friction and wear performance than the untreated NBR. The ATR-IR analysis indicated that the improvement come from the oxygen based functional groups generated on the surface of NBR. The improvement of friction and wear resistance may also come from the formation of nanostructure surface.

In this study, the authors develop the RF AR ion plasma treatment at different bias voltage, and it has been used to modify the surface of NBR to increase the tribological performance.

The purpose of this paper is to: investigate coating of polylactic acid by TiO₂ using low-temperature plasma technique, which is a clean and environmentally benign process; study the characteristics of the obtained samples; and survey the antibacterial effect of nano-TiO₂. This method, as an eco-friendly technology used on the biodegradable polymer, would be benefited by industries which want to set feet on the greener path and reduce the social costs resulting from the harmful effects of pollutants.

TiO₂ was coated on a textile by DC magnetron sputtering. In this study titanium as a pure Ti anode is coated on the sample surface in the plasma reactor by entering argon gas (Ar). Then titanium oxide appears through entering oxygen (O₂) into the reactor.

Scanning electron microscopy analysis is applied to show the morphology of the coated surface. The quantitative value of TiO₂ was evaluated as weight percentage using X-ray fluorescence (XRF) and washing stability of the samples is measured using the XRF machine. The highest degree of antibacterial effects and washing stability are all observed in 10 min.

In this process, contrary to common methods, pure Ti is used for coating. Finishing of textiles via this method has been useful to be used as disposable hospital clothing due to its biodegradable and antibacterial properties. So it will be helpful in reducing negative environmental impacts.

Natural colorants are believed to be safe because of their nontoxic, noncarcinogenic and biodegradable nature, and also, the demand for natural dyes is steadily increasing. This study aims to investigate the dyeing of polyethylene terephthalate (PET) fabrics under cold plasma and ultraviolet (UV) radiation conditions with Prangos ferulacea.

In the first, some PET fabrics were modified using UV radiation and some others by cold plasma (oxygen/argon), and then the dyeing of fabrics with the natural dye was done (100°C/130°C) without using metallic mordant. Dyeability (color strengths) of the treated samples, colorfastness to washing, light and rubbing, water absorption time, crease recovery angle, air permeability and mechanical behavior were investigated.

The maximum color strength (k/s = 4.87) was achieved for the fabric exposed to UV radiation for 2 h and then dyed with Prangos ferulacea at 130 °C. The results indicated that the dyed fabric showed acceptable colorfastness (very good–excellent) properties in washing and rubbing fastness except for colorfastness to light (moderate). The strength and the angle of crease recovery of treated and dyed samples have increased, while the time of water absorption and air permeability have decreased.

The surface modification of PET (UV radiation and plasma treatment) provides a new idea to improve the dyeability of PET with Prangos ferulacea natural dye without using metallic mordant.

The incompatibility of natural fibers with polymer matrices is one of the key obstacles restricting their use in polymer composites. The interfacial connection between the fibers and the matrix was weak resulting in a lack of mechanical properties in the composites. Chemical treatments are often used to change the surface features of plant fibers, yet these treatments have significant drawbacks such as using substantial amounts of liquid and chemicals. Plasma modification has recently become very popular as a viable option as it is easy, dry, ecologically friendly, time-saving and reduces energy consumption. This paper aims to explore plasma treatment for improving the surface adhesion characteristics of sisal fibers (SFs) without compromising the mechanical attributes of the fiber.

A cold glow discharge plasma (CGDP) modification using N₂ gas at varied power densities of 80 W and 120 W for 0.5 h was conducted to improve the surface morphology and interfacial compatibility of SF. The mechanical characteristics of unmodified and CGDP-modified SF-reinforced epoxy composite (SFREC) were examined as per the American Society for Testing and Materials standards.

The cold glow discharge nitrogen plasma treatment of SF at 120 W (30 min) enhanced the SFREC by nearly 122.75% superior interlaminar shear strength, 71.09% greater flexural strength, 84.22% higher tensile strength and 109.74% higher elongation. The combination of improved surface roughness and more effective lignocellulosic exposure has been responsible for the increase in the mechanical characteristics of treated composites. The development of hydrophobicity in the SF had been induced by CGDP N₂ modification and enhanced the size of crystals and crystalline structure by removing some unwanted constituents of the SF and etching the smooth lignin-rich surface layer of the SF particularly revealed via FTIR and XRD.

Chemical and physical treatments have been identified as the most efficient ways of treating the fiber surface. However, the huge amounts of liquids and chemicals needed in chemical methods and their exorbitant performance in terms of energy expenditure have limited their applicability in the past decades. The use of appropriate cohesion in addition to stimulating the biopolymer texture without changing its bulk polymer properties leads to the formation and establishment of plasma surface treatments that offer a unified, repeatable, cost-effective and environmentally benign replacement.

The authors are sure that this technology will be adopted by the polymer industry, aerospace, automotive and related sectors in the future.

The purpose of this paper is to investigate the effects of H2 flow rate on improving the solder wettability of oxidized‐copper with liquid lead‐free solder (96.5Sn‐3Ag‐0.5Cu) by Ar‐H2 plasmas. The aim was to improve the solder wettability of oxidized copper from 0 per cent wetting of copper oxidized in air at 260^oC for 1 hour to 100 per cent wetting of oxidized‐copper modified by Ar‐H2 plasmas at certain H2 flow rates and to find correlations between the surface characteristics of copper and the solder wettability with liquid lead‐free solder.

To reduce the copper oxides on the surfaces of oxidized‐copper for improving solder wettability with liquid lead‐free solder, this study attempted to apply Ar‐H2 plasmas to ablate the copper oxides from the surfaces of oxidized‐copper by the physical bombardment of the Ar plasmas and to reduce the surfaces of oxidized‐copper by the chemical reaction of H2 plasmas with the surfaces of oxidized‐copper.

The solder wettability of oxidized‐copper was found to be highly dependent on the surface characteristics of the copper. The values of polar surface free energy and dispersive surface free energy on the surfaces of oxidized‐copper modified by Ar‐H2 plasmas were close to those values of solid lead‐free solder, which resulted in improved solder wettability with liquid lead‐free solder. Auger spectra indicated that the Ar‐H2 plasma modification was used to remove the copper oxides from the surfaces of oxidized‐copper.

The surface characterization of copper surfaces is typically determined by expensive surface analysis tool such as Auger Electron Spectroscopy (AES). This paper reports the results of a study of a promising technique called the sessile drop test method, for examining the surface free energies such as total surface free energy, polar surface free energy and dispersive surface free energy on the surfaces of copper to clarify how the solder wettability of oxidized‐copper with liquid lead‐free solder was enhanced by Ar‐H2 plasmas.

The rapid progress of ball grid array (BGA) component technology has served to alleviate many problems associated with the placement and soldering of high lead count, fine pitch surface mount technology (SMT) packages. An unfortunate result of this process, however, is the occurrence of voids in the interconnecting eutectic solder balls of these packages. Large voids can affect the mechanical and thermal properties of the interconnect, which can reduce a component’s mean time‐to‐failure and may also affect the transmission of high frequency electrical signals through the solder ball. For this reason, several experiments were conducted to investigate the manner and mechanisms in which voids are introduced into eutectic BGA solder ball joints. The following process parameters were found to be the primary parameters responsible for the voiding phenomenon: condition of the component’s alloy and substrate, oxygen concentration in the reflow atmosphere, solder paste properties and the reflow profile. Through modification and optimization of process parameters in the manufacturing environment, BGA solder joint voiding was greatly reduced.