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State of the Art Manufacturing of Premium Hermetic Components in Malaysia

Key Processes

Glass-to-metal feedthroughs are employed when other sealing options, such as epoxy resins, are no longer sufficient. They can withstand extreme conditions over a long period of time and provide the required reliability for critical applications.

Glass-to-metal seals are produced with special-purpose furnace equipment, using multiple temperature zones and inert or reducing atmospheres. The housings, pins and sealing glasses are assembled into oven fixtures which are then passed into the furnace for sealing.

The furnace temperature (usually at around 1000 °C) causes the sealing glass to melt and wet around the housing and the pins. To prevent oxidation of the parts, the furnace atmosphere must be tightly controlled and consists of an inert or reducing atmosphere. The actual sealing happens during the cooling phase when the glass temperature passes the strain point. The sealing mechanism can be a compression seal or a matched seal depending on the application and chosen materials. It is critical to find the right furnace setting for every part while accounting for the geometry, the used material and the total thermal mass.

Compression seal

Glass and metal are sealed because the thermal expansion of metal and glass create the pressure necessary to make the seal which offers superior mechanical performance.

Matched seal

Glass and Metal have matching rates of thermal expansion in conjunction with a layer of oxide. The oxide layer is key for a matched seal.

High / Low temperature Brazing

Brazing is a process that uses metal braze material that by capillary attraction bonds the surfaces through atomic attraction and diffusion.

After sealing, a plating process is performed for many types of feedthroughs. The function of the plating can be corrosion protection (carbon steel) or enhancing the electrical properties (plating of pins for soldering or wire-bonding).

At final inspection, multiple properties can be checked to ensure quality. Testing possibilities include: Optical inspection, hermeticity-test, burst-pressure test, insulation & electrical testing, flatness, roughness, salt-spray, plating-test, temperature cycling, thermal shock, mechanical shock.