Glass to Metal Seals

ECI's Glass to Metal Seals are a testament to sophisticated production techniques and technical expertise. These seals are designed for a variety of applications, benefiting from ECI's strict adherence to quality control standard ISO 9001:2015. 

Glass to Metal Seals

Glass to metal seals are engineered to perform reliably in harsh operating conditions such as extreme temperatures, moisture, pressure or chemicals. They can also fulfill requirements for long life, performance, and efficiency improvements, as well as innovative designs. The primary function of glass to metal seals is to enable reliable connection and protection for the manufacture of high quality and long lasting hermetically sealed components.

Competence in glass types and formulations is a key expertise in maximizing robustness and reliability. It also includes the selection of the right metal and glass combination for the intended end-use product and proper execution of the sealing process to maximize the integrity of the seal. 

The CTE of glass and metal in matched seals is balanced. Matched seals are typically used for applications where high-temperature variations are present, or tight pin pitch or dimensional requirements (for example, miniaturized or non-round shapes) are factors. Depending on the design, matched glass to metal seals are well suited for semiconductor and optoelectronic assemblies where structural integrity is essential for precise operation of the enclosed electronics.


Due to vastly different CTEs of glass and metal in compression seals, the outer metal eyelet shrinks tightly onto the sealing glass during the production process. This compressive force forms a seal with significant physical strength. In fact, the compressive strength of glass is ten to twenty times higher than its tensile strength. This is why compression seals are typically used for designs with requirements for high mechanical robustness. Usage examples can be found in automotive and energy applications, where long-term seal integrity is essential for continued safe operation of electronics in volatile environments.

ECI’s capabilities range from Microwave-RF packages to legacy glass seal packages such as TO-5 & TO-8 and Power Transistor packages including TO-254 and TO-257. Glass to Metal Seal packages used in Ordnance & Defense applications for detonators, primers and ignition are also available.


Our Glass Flatpack Product Line, sometimes described as Molded Ceramic Packages, are manufactured with a high temperature glass-ceramic material and can be optimized for MW/RF applications, less than 20 GHz.

ECI has introduced a new line of Glass to Metal Feedthroughs available in a wide variety of standard configurations.

ECI now produces high quality 50 Ohm and DC feedthroughs utilizing very tight component tolerances coupled with our advanced manufacturing processes. ECI’s proven ability to consistently supply high-quality components, from small volumes to mass production has made us a leader in the microelectronics industry.

These products include compression, matched, 50-Ohm seals; flanged/flangeless eyelets and machined housings. Options include size, shape, materials, number of I/Os, and interconnects.

The engineering team at ECI is available to help satisfy all your glass to metal seal requirements.

Various pin end styles are available including:

  • Straight Wire 
  • Nail Head 
  • Flattened & Pierced 
  • Flattened 
  • Blind Lug 
  • Loop / Hook
  • Open Lug 
  • Right Angle / Bent 
  • Mechanical Clip 
  • Triple Turret Head 
  • Turret Head 
  • Hollow Tube 

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ECI has been serving customers around the globe for more than 50 years. We would love to work with and share our vast industry knowledge with you. Contact us to get started!

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M2 Global Technology, Ltd. is a premier designer and supplier of RF products and precision manufacturing services, with a strong focus on serving the defense, aerospace, and telecommunications industries. With over 30 years of experience, they provide rapid turnarounds and high-quality components for various aircraft programs and projects.

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