Thin film Coatings – Scaling New Product Development to Accelerate Commercialization

Thin film Coatings – Scaling New Product Development to Accelerate Commercialization?

Many current and emerging technologies require specialized thin film coatings on optical substrates. From antireflection coatings on smart phones, to metallic thin film coatings on 5G antennas and solar panels, to vision systems on self-driving vehicles, vacuum deposited coatings often provide important product functionality and enhancement features. Thin film coatings are comprised of materials such as pure metals, alloys, or ceramics that are applied under vacuum in nanometer thick layers onto surfaces to modify and improve their optical, electrical or environmental performance.??The most common thin film Physical Vapor Deposition (PVD) processes include:

·????????Sputtering – using a gas plasma, atomic layers of coating materials displaced from a “target” and deposited under vacuum on a substrate; good deposition control and ideal for materials with different evaporation rates; can apply high energy ion beam to yield a denser coating??

·????????Thermal Evaporation – a resistive heat source melts materials held in “boats” or crucibles which are then deposited under high vacuum on the substrate

·????????Electron Beam Evaporation – a high energy electron beam provides a targeted heat source to vaporize materials and can be magnetically directed between different crucibles to deposit materials in multiple layers

Table 1 provides an overview of current and emerging technologies that rely on thin film coatings for functional enhancements.

For example, antireflective coatings, comprised of alternating layers of high and low refractive index materials such as Titanium Dioxide (TiO2) and Silicon Dioxide (SiO2), reduce the surface reflections and improve transparency of the coated substrates used in displays and touchscreens and enable them to be viewed in high ambient light.?Thin film coatings of Indium Tin Oxide (ITO), or metals such as copper (Cu) or silver (Ag) are used in a wide range of applications including flexible circuits fabrication and EMI/RFI shielding. Transparent thin film metals and alloys applied to architectural glass are used to reflect or absorb thermal energy and keep buildings cool. ?Diamond like (typically carbon based) coatings are applied to aircraft transparencies to protect surfaces in harsh environments.

Integrating thin film coating features into new products can be challenging from both a design and cost perspective.?The production of thin film coatings requires specialize training to design and operate the expensive, sometimes multi-million dollar vacuum deposition systems.?Consequently, it can be problematic for designers and engineers to incorporate thin film coatings into new product developments and, at times, even to justify the performance enhancement versus cost considerations.??

This article describes how thin film coatings can be successfully designed and integrated into new products at the prototype stage, tested, and then scaled in manufacturing to support commercial production. ??Deposition methods and system considerations to optimize performance and cost will also be discussed.?

Thin Film Coating Design and Process Selection

Primarily, thin film coatings serve to enhance the functional performance of glass, plastics or ceramics by modifying the substrates’ surface to reduce reflections, improve hardness and durability, or make it selectively conductive.??Optical thin film coatings applied under vacuum using electron beam evaporation or magnetron sputtering technology often require an iterative process to produce and verify the coating design. ??The deposition of thin film coatings in nanometer thick optical stacks of materials such as Indium Tin Oxide (ITO), Silicon Dioxide (SiO2), Titanium Dioxide (TiO2) and Magnesium Fluoride (MF3) require insitu optical monitoring (typically Quartz Crystals) and post coating metrology to measure coating parameters.??Depending on the application, optical thin film coatings are typically measured using spectrophotomers to measure transmission (400 to 700 nm) and reflection ( 0 to 30 degrees), haze (light scatter), surface resistance, wave front distortion, surface parallelism and coating durability including temperature, humidity, salt fog, abrasion and adhesion.?

In addition to coating features and testing parameters, the processing format used for thin film coatings can greatly impact cost and performance.??For instance, a one-meter batch coating chamber may be able to run 10 to 20 one square ft. parts per coating run.?In contrast, thin film coatings processed in a roll-to-roll format (R2R) may run at 30 ft./min.??On a one-meter-wide coater, R2R formats can produce more coated material per minute than a batch coater makes per hour.?As a caveat, there are obvious coating design limitations with roll to roll coaters, as well as, the types of substrates that can be coated.

Minimally Viable Product (MVP) Development

The addition of thin film coating features into new products, especially for emerging technologies, often involves the introduction of early-stage products (prototypes) to the market as a means of soliciting customer feedback.?Attributes of a Minimally Viable Product includes: 1) Sufficient Features to attract customers; 2) Future benefits sufficient to retain early adopters; 3) Customer feedback loop to guide future product development.?Incorporating this Voice of the Customer (VOC) input is an essential part of a robust market research and product realization process.?

In order to assess technical and commercial feasibility of adding thin film coatings during product conceptualization, the following criteria should be used to build a business case to move the new product concept into the development stage of the process:

·????????Minimally Viable Product (MVP) initial concept – define optical, electrical and environmental performance; baseline features, value proposition and cost; competitive landscape

·????????Suitability for target market, early adopter customer segment; price vs. features consideration

·????????Thin film coating performance enhancement; visual, functional, durable, aesthetics

·????????Addressable market, time to market and pricing premium of thin film coating enhancement

·????????Expense and logistics of acquiring and integrating thin film coating technology into products

Prototyping and Commercialization

Once a clear value proposition of adding thin film coating features is established, the process of new product design and development should ensure that the product performance meets market expectations and allow for revalidation as new information is obtained from early adopters as shown below in Figure 1:

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The Stage-Gate New Product Development (NPD) process has been widely used in many organizations as a formal method to develop and commercialize new products.?Each stage of the process is a new advancement in the NPD progression and serves as a decision point, where the progress of the product development is reviewed relative to MVP product design, project costs, and technical and commercial performance objectives.???Sequentially, the critical aspects of the Stage-Gate process include:

·????????Market Research – identifying unmet customer needs and the size of the addressable market.?

·????????Business Case - technical and commercial feasibility to move forward with product development

·????????Product Development – laboratory, pilot and low rate production of product

·????????Testing?– performance validation of early versions of the product

·????????Commercialization – market plan including demand creation & product launch, financial metrics

The Stage-Gate steps above follow a repeatable, measurable new product development process which includes criteria to identify and screen market and product design opportunities and make go/no go decisions at the various review stages.?Within each stage, established procedures guide the business and development teams.???

Ideally, the cumulative knowledge of known thin film coating materials, properties and processes is built into the development platform. ?This Agile Development process of create -> measure -> learn -> adapt is especially important with thin film materials used in technical products with high development costs and capital intensive systems. ??Applied material science can further accelerate development velocity by modeling coating performance on various substrates, wavelengths and configurations.?For instance, ITO and metallic alloys will reflect and absorb more at NIR wavelengths and must, therefore be a design consideration if the product will be used for imaging or laser applications outside the visible spectrum.

Understanding the technical and economic aspects of thin film coatings are essential in developing product “road maps”, managing design and scale up processes, and selecting vendors.?Selecting commercially available materials, can significantly reduce front end development costs of “one off” and low volume prototyping.?Furthermore, the cost of thin film coatings is generally dictated by:

·????????Coating complexity – number of thin film layers, coating sequence, performance criteria

·????????Raw materials and testing costs – substrates, coating materials, metrology, environmental

·????????System Type and Size – Batch, In-line or Roll to Roll coating systems; part configuration, size

·????????Part cost - at volume production scale; secondary processing, inspection, and integration

In addition to adding thin film coatings to enhance material and product functionality, the ability to transfer a new product from the laboratory to commercial manufacturing must be considered.?Initially, low rate pilot production of custom coatings are subject to vendor lead times, higher unit costs and minimum order quantities (MOQ’s).?It is especially challenging to simultaneously develop novel materials that require custom manufacturing equipment and new methods to produce them. ?With capital equipment costs of thin film systems potentially in excess of $1.0 mil. and hourly thin film coating manufacturing rates often in excess of $1000/hr., controlling thin film coating costs during product development becomes a priority.?As shown in Figure 2, the use of lab scale batch coaters, commercially available materials, and proven designs can minimize coating schedules and costs and still provide insight on how materials and processes will perform in intended applications and scale in production.

A proven method to offset initial development costs and gain material performance data is to develop a Design of Experiments (DOE) to construct small quantities of different product configurations.?At least in the prototyping phases, small quantities of 8.5” x 11.0” sheet samples and even out of specification production materials may be sufficient for proof of concept testing in the materials screening process.?For DOE applications, batch coating chambers can provide relatively fast and low-cost materials for early screening and determination if the thin film coatings meet the physical, thermal, electrical and mechanical functionality requirements of the product design.?Further time compression during validation can be attained if desired product attributes are already incorporated into the sample material and may only require incremental changes to be an MVP for a new application or customer.???????

Scaling Thin Film Coating Technology in New Product Innovation??

In a variety of aerospace, automotive and industrial prototype applications, thin film coated, flexible polymer films are widely used as a material of choice due to low cost, light weight and ready availability.?Common applications for flexible substrates include polyester films as conductive layers in displays and touch screens, reflective insulation, battery current collectors and low emissivity window films. In developing products to meet market requirements, scientists and engineers add functionality such as printability, mechanical durability, optical transmittance or opacity, color, oxygen or water barrier layers, surface hardness, hydrophobicity, or security features.?

For initial coating development, some batch coating chambers can evaporate or sputter at lower temperatures and serve to model the coating design on polymer substrates prior to scale up on more expensive inline or roll to roll systems.?For volume applications thin film coated flexible substrates are typically coated via roll to roll magnetron sputtering.?See Figure 3.?Therefore, in order to optimize the functionality of flexible substrates, it is important to first understand and define the physical and mechanical characteristics of the base product and what is needed in final product configuration.??Moreover, utilizing DOE’s enable researchers to build on the functionality of an MVP to compress both innovation velocity and life cycle testing.??For instance, organic and inorganic barrier coatings used in packaging applications can be incorporated into higher durability fluoropolymer film laminations for photovoltaic applications.??The vacuum deposition process of metallic Al and Cu layers used in commercial reflective insulation can, likewise, be used in high temperature industrial and aerospace applications.?

In expanding new product designs, developing a rigorous Acceptance Test Plan (ATP) is crucial in establishing the material acceptability prior to scaling a commercial product for a more demanding aerospace or military application.?It should be noted, in the case of military and aerospace materials, that qualification costs of new material are often significant and, therefore, may prohibit new materials being introduced prior to initiating a design change.?Likewise, both the properties of the thin film coatings and technical data and certifications of the base substrates should be considered is using polymer films where processing temperatures of coating, metallizing and laminating operations are critically important.??Material limitations and test data should be thoroughly evaluated prior to proceeding with scale up operations and product positioning strategies.

Testing and Validation

In addition to establishing baseline data on individual components, it is important to determine the functional properties of combined materials.?For flexible substrates, additional coatings, adhesives, colorants and inks intended to add functionality, may alter mechanical, flame resistance or other properties.?To this extent, laminates or composite structures should be tested to simulate real world product usage.?Research has shown that product failures often occur due to multiple stresses. For outdoor applications these stresses can be simulated via accelerated weathering such as damp heat (85 deg. C/85% humidity) combined with UV light and mechanical stress for durations ranging from 1000 to 3000 hours.?These tests are very useful for photovoltaic backsheet materials that need to last in the field without degradation for decades.?Similarly, thin film metalized substrates used in Li-ion battery construction, need to be precisely coated and manufactured to preserve safe operation.?Due to the significant liability of long term product warranty issues, selecting proven materials such as UV and hydrolysis resistant films, foils and adhesives is imperative.?Preceding the scale up process, lab testing can validate design and demonstrate product robustness, while field testing provides extremely valuable customer feedback.

Scale Up, Costing and Commercialization

Once a product has been laboratory and field tested.?Product validation moves to pilot production, as the next critical gate in the development process.?With flexible substrates thin film coated via a R2R process, web tension, process temperature, coating weight and drying temperature are all critical parameters.?A pilot coating trial conserves material and time and provides insight on how well the materials and processes will scale on production assets.?Once the pilot stage gate is completed, scale up manufacturing methods, efficiency, throughput and product quality become the focus.

It is critically important in NPD to meet cost objectives and launch dates; being on time and within budget.?On the process side, Design for Manufacturing (DFM), the ability to produce a robust product is equally important, as well as safety, waste minimization and robust supply chain integrity.?Societal trends such as sustainability, recyclability, volatile organic compounds (VOC’s) reduction and solvent free coating and lamination methods, are also considerations in material selection and manufacturing methods.

In production, costs are primarily driven by raw materials, capital equipment investment and manufacturing efficiency including production speed, scrap and rework. Many new, potentially promising products, never move to the commercial stage because they cannot meet the cost objectives outlined in the business case or provide sufficient product value for a pricing premium.?Invariably, successful commercializations include process optimization, “cost down” material improvements, and in some cases, capital investment. ??The return on investment for thin film coating systems is ultimately tied to initial system investment, throughput and ancillary manufacturing support services. ?From a material perspective, thinner “down gauged” substrates and are often used for material conservation.?On the manufacturing side, process engineering can often improve machine speeds, product yields, quality and throughput.?Leveraging thin film coating and system selection expertise with process optimization will generally increase the chances of technical and commercial success in NPD.??

Market Access & Support

Collaborating with thin film coating system manufacturers and coating suppliers can usually reduce the costs, timeline and risks associated with integrating thin film coatings into new products.?Additional benefits of collaborative development is generating referral and support for upstream and downstream supply chain needs for new products.?In this case, coating system manufacturers, substrate suppliers, converters, coaters, laminators and distributors all fulfill different niches within the marketplace.?Consequently, new products can be sold into different market segments, and in various configurations and quantities based on end-user requirements.

In summary, the thin film coating systems, materials and tests outlined in this article provide a proven process for adding functional properties to new materials used in industrial, aerospace and commercial applications.?The key in collaborative innovation is to select development partners that have a deep “Technology Toolbox” and material science expertise to support innovation, compress R & D project timelines and reduce costs.?At the same time, a partner with the thin film coating systems and expertise to scale up and commercialize new technology is invaluable in turning your company’s concepts into new products.?