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Editor's Note: This column originally appeared in the November issue of The PCB Magazine.
The electronics industry is experiencing a significant period of change, with modern manufacturing being driven by the demand for high-reliability, lightweight and increasingly complex electronic components. With electronics being at the core of growth, it is vital that manufacturers continue to provide innovative and reliable solutions to address the changing requirements of the industry. To weather the current economic storm, electronics manufacturers need to build on the established markets to which they supply, as well as expand into new areas where proven technologies are of value.
Meeting Existing Demand
Aerospace and defence has long been an area where high-reliability electronic components have played a key role. However, transformational changes have swept across the aerospace and defence arena. The current economic climate has underlined the importance of cost effectiveness--encouraging innovative, cost-saving strategies. According to industry analysts Frost & Sullivan, the nature of operating in the aerospace and defence industry is significantly different from other traditional and commercial markets. Electronics providers face complex manufacturing requirements, very high-quality requirements and low- to ultra-low volume production demands . Growing complexity in product designs and supply chains will elevate providers to the position of a strategic partner.
Frost & Sullivan recently predicted average growth in the commercial avionics market at 5.2% over the next decade . With the worldwide aerospace industry expanding at such a rapid rate, the challenge for manufacturers is to ensure they are positioned to meet increasing demand for reliable, efficient and innovative systems. Ceramic-based circuitry will continue to underpin the electronics for optimum reliability in extreme conditions, and with the particularly stringent quality required from the aerospace industry, it is becoming vital for manufacturers to look for proven ways to adhere to the strict standards and accreditations that products must meet.
Reliability is Key
The majority of electronic components are required to operate in relatively benign environments, functioning well within their design specifications for many years. In contrast, the components and assemblies destined for use in very harsh environments (wide temperature ranges, high-vibration conditions and confined spaces, for example) are often employed in the mission-critical applications where failure could be catastrophic for the system. While everyday electronic components are often discarded without a second thought when they fail, the electronic systems used in aerospace and defence markets must be absolutely reliable to meet the objectives of the mission.
Aerospace is an industry that necessitates absolute reliability from its electronics--it can genuinely be a matter of life or death on a day-to-day basis. For hermetic products, this is reflected in the rigorous tests insisted on by military standards such as MIL-PRF-38534 and MIL-STD-883. The engineering teams responsible for compliance with these standards must maintain pace with the fast-developing packaging technologies and implement comprehensive electronic test and qualification regimes.
For those companies that are able to produce the high-quality, high-reliability products required by the aerospace and defence industries, new avenues are opening up, as other industries look for electronic components that can function in extremely harsh environments.
Venturing into Space
The space industry has a clear need for high-reliability electronic components, as the cost of failure multiplies exponentially in space, and as such is an obvious area of expansion for high-reliability electronic manufacturers. Satellite programmes cost billions and even small errors can undermine the very reason they were sent into space in the first place, especially when under scrutiny of taxpayers. The long life of applications sent into space requires components to be completely reliable. They need to function for the life of the flight as failure would not only be expensive and embarrassing, but could also mean the early end of a promising mission. To this end, it is imperative that electronic packaging uses low out-gassing adhesives or eutectic bonds to maintain high performance over long operating life times.
The rigors of the space environment create a very particular set of conditions. Protection from radiation is widely recognised as critical to survivability of electronics in satellite applications. High levels of ionising radiation to which satellites are exposed threaten to influence the components so package design with filtering and shielding, as well as basic radition tolerance of the semiconductor, is crucial to ensure the high reliability of a system. In addition to ionising radiation, thermal energy is a big concern. The typical failure mode occurs at the active junction of semiconductor devices, which often have a continuous maximum operating temperature of between 150°C and 200°C. Packaging must be designed to ensure that manufacturers’ recommended maximum temperatures are not exceeded.
Exploring New Depths
Over the past decade, drilling for hydrocarbon fuels has become increasingly challenging and is being driven by the fact that more readily accessible oil and gas reserves have been tapped long ago. Consequently, the industry is being forced to drill in harsher environments, along horizontal paths (rather than conventional vertical drilling) at ever-increasing depths. Down-well tools need to function in increasingly extreme conditions, driving demand for the high-reliability electronics proven in other industries. The failure of a measurement tool in drilling a 20,000-foot-deep well could readily incur two days delay, which for an offshore platform is in the region of a $1,000,000 to $2,000,000 loss. Oil and gas companies are incurring multi-millions in lost revenue due to system unreliability and inefficiencies so reducing drilling “down-time” has become a major industry objective.
For this reason, it is crucial that the accuracy of drilling and the characterisation and analysis of minerals and rock structures, as well as oil and gas sampling, is performed with the highest precision. Three key areas in oil and gas drilling require these reliable “down-hole” instrumentation electronics, which are commonly known as “tools:”
- Wireline logging tools: These tools are used for measurement and contain sensors (electro-magnetic, gamma, seismic, acoustic and vibration) that gather snapshot information about the quality and production capability of the well. These are usually electrically connected to the well head for power supply and signal communications.
- Measurement while drilling (MWD) and logging while drilling (LWD) tools: These tools are mounted directly behind the drill head and are based around sensors that detect drill orientation and direction and measure the mineral and organic material characteristics within the well. They are exposed to the high temperature of the environments and the shock and vibration associated with the drilling activity. Tools like these typically operate from 30°C to 175°C (90% of operations) and with occasional transitions up to 225°C (99% of operations).
- Intelligent completions: These systems incorporate sensors that measure parameters such as oil and gas pressure to enable prediction and hence management of the quality and productivity of the well. They are installed in “producing” wells and deliver information to the well head for the lifetime of the well which may extend many years.
Due to the increasing commercial demands being placed on down well measurement tools there is now a pressing need for robust electronics that have enhanced functionality to quickly and reliably monitor and process data such as temperature, pressure, resistivity, neutron porosity and gamma trace, as well as providing drill directional guidance. Therefore, over recent years, the level of financial investment in the development and qualification of high-temperature electronics has grown significantly as the requirement for complex electronic systems that operate with predictable lifetime under challenging mechanical shock and vibration increases.
Learning from Others
Electronic packaging technologies have been advancing rapidly over the last few years as manufacturers continue to design smaller, lighter, more effective solutions to meet the complex demands of high-signal frequencies and increasing component power dissipations and densities. Despite the accepted and in many cases authorised usage of commercial-off-the-shelf (COTS) component grades for space, aerospace and defence electronics, the industry is increasingly looking to customise and modularise their offering--providing advances in performance, cost, size and mass, but crucially, with improved reliability.
Aerospace has traditionally been the heartland of low-volume, high-reliability electronics, and several manufacturers have successfully built on this heritage to provide solutions for other challenging markets, such as space and oil and gas. We’ve been seeing this technology transfer between markets for a while now, but what’s new is that technology advances are now transferring back. For example, high-temperature technology developed for the oil and gas market, based on expertise developed in aerospace, is in turn being used in aerospace applications which are seeking operating temperatures above the traditional military maximum of 125°C.
The need for high-reliability electronics that can perform in harsh environments is increasingly similar across a number of markets, only the drivers are different. As the proportional cost and content of electronics becomes more significant in the overall system budget so will the drive by manufacturers and integrators to find the optimum electronic hardware solutions for their applications.
The environment presents electronics manufacturers with an exciting opportunity to build on their heritage and expand into new areas, learning lessons from the industries where high-reliability is the key to success. References: 1. Frost & Sullivan, “World EMS Provider Market in the Aerospace and Defense Industry.” 2. Global Commercial Avionics Markets to Benefit from Better Market Conditions, Says Frost & Sullivan.
Bob Hunt holds the position of Head of Strategic Technology for C-MAC MicroTechnology and is based in Great Yarmouth, UK. He directs the medium- and long-term business strategy in the areas of technology and products. Hunt graduated with BSc (Hons) and MSc in electronic engineering and has a career spanning 25 years in microelectronic and optoelectronic circuit and package development. His principle expertise is with high-reliability, military and aerospace products and applications.