Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process utilized in assembling micro-electronic packages for communication, aerospace and medical device manufacturing.

Uses of hermetic sealing
Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging and power amplifiers. By sealing these electronic packages, external contaminants – like moisture – are kept out preventing degradation of the electronic components inside and extending lifetime usefulness.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic package types
There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Parallel gap resistance seam welding
Parallel gap seam welding is one way to execute a hermetic seal. A seam welder with rolling wheel electrodes is connected to a power supply, which is responsible for delivering electric current across the electrodes, through the lid and the package. The seam welder delivers multiple overlapping weld spots, thus creating a continuous weld (Figures 2 and 3).

Read more: Hermetic sealing technologies enable reliable welds, protect electronic devices

You’ll need sensors to complete your new appliance, building automation product or automated manufacturing system. You may need customization for a specific sensor assembly. While price and delivery are critical decision factors, other considerations determine a successful sensor selection. Here are some essential facts about sensor choices and four crucial questions whose answers should carry significant weight in your decision process.

Magnetic detection sensors for proximity detection, positioning and control
Reed switches have two ferromagnetic blades (reeds) hermetically sealed in a tubular glass envelope. The contacts on each reed have a thin layer of precious metal to provide a low resistance electrical connection. The glass envelope is filled with nitrogen gas to eliminate oxygen and prevent contact oxidation. Reed switches can be activated by either a permanent magnet or an electromagnet. The relative stiffness of the reed blades, the small gap and the overlap between the two contacts determine the switch’s sensitivity, defined by the intensity of the magnetic field required to change the state of the contacts. Unlike an integrated circuit sensor, a reed switch does not require power to operate. Thus, a reed switch is an excellent control element in battery-powered products.

Hall effect sensors generate a voltage when exposed to a magnetic field intensity and when supplied by a source current. The sensor is a semiconductor-based material. Hall voltages are microvolt and millivolt levels; thus, a Hall effect sensor requires signal conditioning. In addition, the semiconductor element requires temperature compensation and EMC/ESD protection. Hall effect sensors monitor proximity and provide continuous rotary or linear positioning.

Reed relays combine a reed switch and control coil. As with other relays, this provides galvanic isolation between the coil control circuit and the controlled load. The reed relay’s small size and high magnetic efficiency enable lower coil drive power than other relay types. Other advantages include high insulation resistance, low contact resistance and long contact life.

TMR switches integrate tunneling magneto resistance (TMR) and CMOS technology to provide a magnetically triggered digital switch with high sensitivity and ultra-low power consumption. It contains TMR magnetic sensor and CMOS signal processing circuitry within the same package, including an on-chip TMR voltage generator for precise magnetic sensing, a TMR voltage amplifier and comparator plus a Schmitt trigger to provide switching hysteresis for noise rejection. An internal bandgap regulator provides a temperature compensated supply voltage for internal circuits, permitting a wide range of supply voltages.

Temperature sensors
Thermistors are thermally sensitive resistors whose resistance is a function of their temperature. Negative temperature coefficient (NTC) thermistors decrease their resistance when the temperature rises, and positive temperature coefficient (PTC) thermistors increase their resistance when the temperature rises. Thermistors provide high accuracy over a narrow range of approximately -50° C to 100° C. Thermistors have highly predictable characteristics and excellent long-term stability; they’re ideal sensors for temperature measurement and control applications.

Platinum resistance temperature detectors (Pt-RTDs) have a near-linear change in resistance with any temperature changes. Pt-RTDs maintain a significant and uniform rate of resistance change over a much wider operating temperature range than a thermistor. Pt-RTDs are excellent for measurement and control applications with temperatures ranging from -70° C to 500° C.

Read more: Common sense about sensors: 4 questions to ask before selecting sensors for your next design

Subassemblies, modules, and components developed for various military applications, such as avionics, ground vehicles, and portable electronics, all need to operate in a variety of harsh environments, which range from extreme temperatures to high shock and vibration. At the same time, lighter and smaller designs are critical for space- and weight-constrained systems, and durability and reliability are at the top of the list of big concerns. These stringent demands translate into big challenges for connector makers to ensure that the interconnects provide highly reliable and fast connections over extended use and in harsh conditions.

Connector makers also need to consider a multitude of design requirements such as mating cycles for long life, ingress protection and ease of use. High-speed data transmission capability also is becoming a bigger factor in new communication designs. While component manufacturers need to meet specific military standards and specs, many connector manufacturers are developing their own advanced technologies and processes to provide a higher level of reliability and usability.

Addressing the need for watertight products in harsh environments, Cinch Connectivity Solutions, a Bel group company, recently released its Cinch Mil/Aero Circulars’ DMS-TP series. These connectors are waterproof when temporarily immersed up to 300 meters, and they are resistant to corrosion. They are also designed for ease of use with scoop-proof shells. The nickel-plated brass shells allow the connectors to withstand prolonged use in the presence of oil, gas, sand, mud, hydrocarbons, and salt.

The Cinch circular connector series offers a full range of frequencies, insulation resistance, dielectric withstanding voltage, operating voltage or capacitance. They also are available in hermetic sealing in any circular connector configuration. These glass, ceramic or epoxy-sealed packages can be used in components or assemblies in harsh environment applications that demand no leakage even under extreme changes in temperature, pressure, humidity and intense vibration, said the company.

A new circular connector from ITT Cannon also addresses ingress protection. Cannon’s Nemesis II CBA 20+ meters is a high-speed, high-mating and quick-termination interconnect that has been tested for water submersion to 20+ meters (65.6 feet). The miniature circular interconnects, designed for soldier-worn applications, operates in extreme and harsh environments so it can be used in battlefield communication devices and applications. It provides power, signal and data in a smaller integrated design to deliver reliable communications in a reduced weight solution. In addition, the breakaway functionality allows soldiers to quickly disconnect/reconnect their cables and equipment if they become caught, and the connector easily terminates to wire, PCB and flex circuits.

Read more: Building a Better Rugged Connector for Military Products

Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process used in assembling microelectronic packages for communication, aerospace, and medical device manufacturing.

Uses of Hermetic Sealing

Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging, and power amplifiers. By sealing these electronic packages, external contaminants—like moisture—are kept out preventing degradation of the electronic components inside and extending their lifetime.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic Package Types

There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Read more: Want Reliable Welds? Hermetic Sealing Can Help

Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process utilized in assembling micro-electronic packages for communication, aerospace and medical device manufacturing.

Uses of hermetic sealing
Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging and power amplifiers. By sealing these electronic packages, external contaminants – like moisture – are kept out preventing degradation of the electronic components inside and extending lifetime usefulness.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic package types
There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Parallel gap resistance seam welding
Parallel gap seam welding is one way to execute a hermetic seal. A seam welder with rolling wheel electrodes is connected to a power supply, which is responsible for delivering electric current across the electrodes, through the lid and the package. The seam welder delivers multiple overlapping weld spots, thus creating a continuous weld (Figures 2 and 3).

Read more: Hermetic sealing technologies enable reliable welds, protect electronic devices

Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process utilized in assembling micro-electronic packages for communication, aerospace and medical device manufacturing.

Uses of hermetic sealing
Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging and power amplifiers. By sealing these electronic packages, external contaminants – like moisture – are kept out preventing degradation of the electronic components inside and extending lifetime usefulness.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic package types
There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Parallel gap resistance seam welding
Parallel gap seam welding is one way to execute a hermetic seal. A seam welder with rolling wheel electrodes is connected to a power supply, which is responsible for delivering electric current across the electrodes, through the lid and the package. The seam welder delivers multiple overlapping weld spots, thus creating a continuous weld (Figures 2 and 3).

Read more: Hermetic sealing technologies enable reliable welds, protect electronic devices

Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process utilized in assembling micro-electronic packages for communication, aerospace and medical device manufacturing.

Uses of hermetic sealing
Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging and power amplifiers. By sealing these electronic packages, external contaminants – like moisture – are kept out preventing degradation of the electronic components inside and extending lifetime usefulness.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic package types
There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Parallel gap resistance seam welding
Parallel gap seam welding is one way to execute a hermetic seal. A seam welder with rolling wheel electrodes is connected to a power supply, which is responsible for delivering electric current across the electrodes, through the lid and the package. The seam welder delivers multiple overlapping weld spots, thus creating a continuous weld (Figures 2 and 3).

Read more: Hermetic sealing technologies enable reliable welds, protect electronic devices

Global demand for affordable satellite communications for applications ranging from cell phone connectivity and television content, to space-based military and agriculture surveillance and monitoring are driving huge increases in small satellites and the radiation-hardened electronics that make them function effectively.

It is this need for radiation hardening that focuses the electronics industry’s efforts on developing components like microprocessors, power-management devices, and solid-state memory that are inexpensive to buy, yet resilient enough to survive in space for periods ranging from weeks to years.

“We are really starting to see four quantums in the satellite space marketplace,” explains Anthony Jordan, director of business development at Cobham Advanced Electronic Solutions Inc. (CAES) in Colorado Springs, Colo. These four quantums consist of small cubesats with mission durations of only 12 to 18 months; business satellites with life spans of two or three years of mission life; so-called “constellation space” with each satellite expected to last in orbit for five to seven years; and finally the long-duration satellites that will operate in geosynchronous orbits for decades.

Four space segments

The first quantum primarily is for proof-of-concept research projects and can accept non-rad-hard components. The second quantum must have limited radiation
hardening for short durations in low- or medi­um-Earth orbits. The third quantum must have some serious radiation hardening for multi-year missions; and the fourth quantum must have the most extensive levels of radiation hardening for decades of operation in harsh geosynchronous and polar orbits.

The whole idea is to design, test, or upscreen electronic components that are good enough for their intended applications, while keeping size, weight, power consumption, and cost (SWaP-C) to a minimum to meet mission goals.

Read more: The evolving world of radiation-hardened electronics for space

Hermetic sealing is the encapsulation of electronic components into an airtight metal or ceramic housing using either parallel gap resistance seam welding or opposed electrode projection resistance welding. It is a key manufacturing process utilized in assembling micro-electronic packages for communication, aerospace and medical device manufacturing.

Uses of hermetic sealing
Microelectronic devices are commonly used in industrial commercial communications, transportation, military, and aerospace industries and include optical sensors, pressure sensors, communications devices, thermal and laser imaging and power amplifiers. By sealing these electronic packages, external contaminants – like moisture – are kept out preventing degradation of the electronic components inside and extending lifetime usefulness.

Implantable medical devices, like pacemakers and defibrillators, also require careful hermetic sealing to protect both the device and the patient.

Microelectronic package types
There are two primary types of packages: metallic tub and ceramic.

The preferred material for metallic tub base packages is Kovar, which has a similar Coefficient of Thermal Expansion (CTE) as glass; the use of this material prevents the metal-to-glass seals of the feedthrough connectors of the package from leaking due to material expansion from heat generated during the welding process.

Ceramic packages are made of a ceramic substrate with a brazed metal seal ring. Kovar is also used in ceramic packages; the Kovar is brazed onto the ceramic base as a seal ring to which the lid is welded.

Parallel gap resistance seam welding
Parallel gap seam welding is one way to execute a hermetic seal. A seam welder with rolling wheel electrodes is connected to a power supply, which is responsible for delivering electric current across the electrodes, through the lid and the package.

Read more: Hermetic sealing technologies enable reliable welds, protect electronic devices

The only option in harsh operating conditions
Hermetic packaging of electronic components or systems is often a requirement when harsh or advanced operating conditions apply. Examples include automotive electronics that need to function even when exposed to high temperature variations and driving vibrations, safety-relevant nuclear power electronics that are exposed to harmful radiation yet must not fail in case of an accident, and medical device electronics that need to endure regular steam sterilization procedures for safe re-use.

Increasing system reliability and safety
Beyond challenging operating conditions, hermeticity can be beneficial in case of special longevity or efficiency requirements. This includes applications that cannot compromise on safety or reliablity (such as automotive airbags or defense electronics) or where maintenance, repairs, or exchange of an electrical system is impossible or would result in prohibitive costs – as is the case in many avionics, aerospace, and maritime applications.

Performance, efficiency, and design innovation
Airtight hermetic seals can also enable significant performance and efficiency improvements, as well as innovative designs. A truly air-, or water-tight housing is needed to enable long-term and consistently high-performance data transmission in opto-electronic data- and telecom applications.
Hermetic packaging may also be a cost-efficient alternative to non- or quasi-hermetic seals, as it can allow smaller, miniaturized, and simplified single-component designs, instead of larger, more complex multi-components systems. Hermetic seals can also be designed to cater to increased heat dissipation, high power/ voltage/ insulation, or high
frequency / RF optical data transmission requirements.

Read more: When is Hermetic Sealing Useful?