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ramé-hart
Newsletter
July 2023 |
| Cursory Overview of Applications that Benefit from Contact Angle - Part 2 |
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Last month we began looking at a number of applications and industries that benefit from a better understanding of contact angle and wetting behavior. This month, we will continued our list: Semiconductors In the fast-paced world of semiconductor chip manufacturing, achieving optimal performance, precision, and reliability is paramount. Makers of these advanced computer chips are constantly seeking innovative methods to enhance their fabrication processes. Contact angle analysis, a powerful technique rooted in surface science, offers valuable insights that can revolutionize the production of semiconductor chips. By harnessing the benefits of contact angle measurements, chip manufacturers can optimize surface treatments, improve adhesion, and enhance overall chip performance. The intricate process of fabricating semiconductor chips involves numerous surface treatments that play a critical role in performance and reliability. Contact angle analysis enables chip manufacturers to precisely evaluate and tailor these treatments to achieve optimal results. By characterizing the wetting behavior of fluids used in surface treatments, such as etchants, cleansers, and coatings, contact angle measurements provide essential data to optimize process parameters, ensure uniformity, and enhance adhesion between different layers and materials.
The effective bonding and adhesion of various layers within a semiconductor chip are vital for its functionality and durability. Contact angle analysis allows chip makers to assess the wetting behavior and surface energy of bonding agents and adhesives. This knowledge enables the selection of suitable materials and formulations that promote strong interfacial adhesion, reducing delamination and improving overall chip reliability. By leveraging contact angle measurements, manufacturers can enhance the bonding process, optimize material compatibility, and reduce the risk of failure due to poor adhesion. Surface modifications play a crucial role in semiconductor chip manufacturing, enabling precise patterning, contamination control, and improved electrical performance. Contact angle analysis provides a comprehensive understanding of surface modifications, such as plasma treatments, coatings, and functionalization techniques. By characterizing the wetting properties and surface energy changes resulting from these modifications, chip manufacturers can precisely control the effectiveness of these processes. This knowledge empowers them to fine-tune surface properties, enhance patterning accuracy, minimize defects, and improve the overall performance of the chips.
The semiconductor industry operates on razor-thin margins, and optimizing yield and performance is crucial for success. Contact angle analysis offers a powerful tool for quality assurance and process control. By monitoring contact angles at different stages of chip fabrication, manufacturers can detect variations, identify potential issues early, and implement corrective measures to maximize yield and consistency. Additionally, contact angle measurements enable chip makers to optimize critical parameters, such as surface cleanliness, surface roughness, and film thickness, to ensure consistent and high-quality chip production. Hard Disk Drives The manufacturing processes of a magnetic hard disk and its associated magnetic head slider exhibit a significant dependence on surface cleanliness and surface wettability, particularly concerning the application of lubricants onto the surface. Parameters such as contact angle and surface energy assume a pivotal role in facilitating engineers' endeavors to design and assess hard drive products that effectively mitigate stiction, minimize flying height, and enhance overall product reliability. Mining In the mining industry, a comprehensive understanding of contact angle assumes considerable significance, particularly in the context of froth flotation, a process employed to concentrate minerals of heavy metals such as zincblende, galena, chalcopyrite, and others. This technique involves the agitation of finely divided minerals within a froth consisting of water and air, causing some minerals to float while others sink. The valuable minerals selectively adhere to air bubbles, rising with them to the froth layer where they are subsequently collected. The ease with which a particle floats is influenced by the contact angle formed at the interface between the particle, water, and air. A smaller contact angle impedes the flotation process. To address this, measures are taken to increase the contact angle, often up to 60 degrees, by introducing specific chemical agents known as "collectors." Alkyl xanthanates (such as CH3.O.CS.Sna) are commonly used collectors in this regard. By incorporating these collectors, the contact angle is effectively enhanced, enabling improved flotation efficiency and mineral recovery. Chemicals In the chemical industry, heat exchangers and condensers play a crucial role, and attaining optimal efficiency necessitates the utilization of non-wetting agents, such as calcium stearate or oleic acid, to coat the metal surfaces. By employing these coatings, liquids that condense on the treated walls form distinct droplets due to the high contact angle exhibited, facilitating their easy detachment and downward flow. This technique is commonly referred to as "dropwise" condensation. Measurement of the contact angle assumes significance in effectively controlling the surface area of the droplets, thereby enabling the manipulation of evaporation rates and facilitating the optimization of surface wetting in heat exchangers. Through careful control of the contact angle, the desired balance between droplet growth and shedding can be achieved, ultimately enhancing heat transfer efficiency and promoting optimal performance of the system. Detergents Contact angle also plays a significant role in the domain of detergency, which involves the cleaning of garments and other items using surface-active agents. To effectively eliminate dirt, grease, oil, and other contaminants from soiled fabrics, it is imperative that water can spread and penetrate the particles of dirt. The occurrence of spreading hinges on minimizing the interfacial tension between the solid-liquid and liquid-vapor interfaces. In this context, detergents play a vital role by reducing these interfacial tensions through the process of adsorption. By adsorbing onto the surfaces, detergents lower the interfacial tensions, thereby facilitating the desired spreading of water and subsequent penetration of dirt particles. The formulation of lotions, oils, soaps, and other toiletries for human skin and hair strands benefits greatly from contact angle measurements, as they provide crucial insights for achieving precise formulations. Consequently, contact angle measurements have become an integral part of the routine practices in this field, aiding in the development of effective and appropriate products. Metallurgy A comprehensive understanding of the contact angle behavior exhibited by liquid metals on metal and oxide surfaces assumes paramount importance in elucidating various processes such as soldering, brazing, tinning, and heat transfer. The characterization of surface roughness, oxidation, and wetting behavior for diverse types of metals and metal finishing relies heavily on the utilization of contact angle measurements. In the realm of soldering, brazing, and tinning, knowledge of the contact angle aids in comprehending the interactions between the liquid metal and the substrate, which is crucial for achieving proper wetting and bonding. It allows for the assessment of surface compatibility, the influence of surface roughness on wetting behavior, and the impact of oxide layers on bonding quality. Furthermore, in the context of heat transfer, understanding the contact angle behavior facilitates the optimization of heat dissipation and thermal management in various applications. By employing contact angle measurements, engineers and researchers can gain valuable insights into the intricate dynamics of liquid metal behavior on metal and oxide surfaces. This knowledge serves as a foundation for enhancing process efficiency, quality control, and overall performance in soldering, brazing, tinning, and heat transfer applications across different industries. Plating and Printing and Inks Achieving successful plating operations necessitates meticulous attention to surface cleanliness. The contact angle parameter serves as a predictive indicator for adhesion and finds extensive use in quality assurance testing of surfaces intended for plating. Notably, ASTM Standards, such as D7490 and D7334, have incorporated contact angle measurements to assess wettability, a critical factor in ensuring optimal adhesion and mitigating surface-related issues such as cratering, dewetting, and crawling. While wetting is instrumental in promoting adhesion, it is crucial to strike the right balance, as excessive wetting can lead to undesirable outcomes such as ink bleeding and impaired functionality. In the production of inks, the contact angle formed by an ink droplet on paper plays a decisive role in determining printing quality. Empirical observations have established that an ideal contact angle falls within the range of 90 degrees to 110 degrees. A contact angle lower than 90 degrees results in ink spreading on the paper, while a contact angle exceeding 110 degrees leads to printing failures characterized by breaks or interruptions. By carefully controlling the contact angle in ink manufacturing processes, practitioners can optimize printing quality and prevent issues associated with improper wetting. Adhering to the recommended contact angle range ensures satisfactory ink performance, enabling accurate and reliable printing outcomes. Other Applications The comprehensive examination and measurement of contact angles between liquids and solid surfaces hold significant technological implications. This significance is particularly pronounced when considering water, as its interaction with solids governs numerous phenomena and processes on Earth. The wetting behavior of water on a solid surface profoundly influences its behavior. For instance, the contact angle of water on human skin measures approximately 90 degrees. If this angle were reduced to zero, water would be capable of infiltrating the skin's pores and potentially being absorbed into the bloodstream. In the case of bird feathers, their unique structure is designed in such a way that the contact angle of water on a typical feather is remarkably high, often reaching around 150 degrees. This exceptional contact angle contributes to the feather's hydrophobicity, preventing water from adhering and maintaining the bird's insulation and flight capabilities. To safeguard machines, such as lathes, particularly during transportation, preventive measures such as the application of a thin layer of grease or oil are employed. This protective coating acts as a highly non-wetting barrier with water, thus impeding the corrosion of machine surfaces. The formation of this non-wetting system effectively isolates the machine components from potential water-induced damage. By conducting in-depth investigations into contact angles and their implications, researchers and engineers can gain crucial insights that contribute to the development of technological advancements, improved materials, and enhanced surface treatments. In addition to the previously discussed applications, contact angle measurements find wide-ranging utility in various other fields and industries. Notably, the characterization of contact angles contributes to the advancement of adhesives, lubricants, surface treatments, polymers, biomedicine, and numerous related disciplines. While the scope of specific examples is extensive, the aforementioned applications underscore the pivotal role played by contact angle analysis in diverse manufacturing sectors. For instance, in the domain of adhesives, contact angle measurements aid in assessing the wettability and adhesion properties of adhesive materials on different surfaces. This knowledge informs the development of improved bonding agents and optimized adhesive formulations, ensuring reliable and durable adhesive bonds. In the field of lubricants, contact angle analysis facilitates the understanding of the wetting behavior and film formation characteristics of lubricating fluids on various substrates. This insight guides the selection and formulation of lubricants tailored to specific applications, optimizing friction reduction, wear protection, and overall lubrication performance. Surface treatments benefit from contact angle measurements as they enable the evaluation of surface energy, hydrophobicity, and surface modifications to enhance wetting or repelling properties. These measurements aid in designing coatings, paints, and surface treatments that exhibit desired functionalities such as anti-fouling, self-cleaning, or improved adhesion. Contact angle analysis plays a crucial role in characterizing the surface properties and wetting behavior of polymers, enabling the optimization of processes such as molding, coating, and printing. This knowledge guides material selection, surface modifications, and formulation adjustments to achieve desired performance and manufacturing outcomes. In biomedicine, contact angle measurements provide insights into the interaction between biological fluids, tissues, and medical devices. By assessing the wetting behavior and surface properties, researchers and engineers can design biocompatible materials, coatings, and implants, improving the efficacy and safety of medical devices and enhancing patient outcomes. These examples, among many others, demonstrate the wide-ranging significance of contact angle measurements across numerous manufacturing industries. By harnessing the knowledge gained from contact angle analysis, researchers and practitioners can advance their understanding, optimize processes, and develop innovative solutions to meet the diverse needs of various industrial sectors. |
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Regards,
Carl Clegg |
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