Glass-to-glass sealing — Primoceler®

Glass-to-glass sealing technology by SCHOTT Primoceler Oy is the ideal solution for engineers requiring hermetic packaging with superior miniaturization, RF transparency, and production efficiency. Learn about the technology's key advantages, applications, and manufacturing process as well as how our expertise can support innovation with next-generation hermetic sealing.
Introduction

What is Primoceler® glass-to-glass sealing?

Also known as “glass micro bonding”, SCHOTT Primoceler Oy’s glass-to-glass sealing process is a revolutionary hermetic packaging technology that uses precisely stacked glass wafers to create cavities that safely encapsulate sensitive electronics. The electronic devices are laser-sealed along the edges using advanced room-temperature glass welding technology, after which the wafer is diced into tiny individual devices. This highly efficient wafer-level process drives innovation in demanding applications by enabling the efficient manufacturing of very small, yet extremely robust all-glass enclosures.

Benefits

Benefits of glass-to-glass micro bonding

Applications

Applications

Glass-to-glass sealing technology by SCHOTT Primoceler Oy offers intriguing implementation possibilities for a variety of applications. Examples include active medical implants, aerospace, MEMS, and micro-optics.​

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    Active implantable medical devices​

    For 40 years, medical implants have been encapsulated in titanium. Now, with glass-to-glass sealing by SCHOTT Primoceler Oy, an entirely new breed of ultra-miniaturized, fully glass-encapsulated implants is possible. The sealing process uses specially formulated biocompatible and RF-transparent glass, allowing wireless data and power transfer.
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    Aerospace

    Primoceler® technology enables miniature, lightweight hermetic packages that are highly robust even in harsh environments. These packages deliver stable device operation, which is critically important in aerospace settings where failure is not an option. SCHOTT Primoceler Oy has experience working on projects supporting the European Space Agency and other leading organizations.
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    MEMS

    SCHOTT Primoceler Oy utilizes glass micro bonding to create hermetic packages for MEMS using ultra-thin glass to maximize the die-to-package ratio. The precise, room-temperature laser-sealing doesn’t affect enclosed active parts while also protecting them from moisture. For feedthroughs, highly reliable SCHOTT HermeS® hermetic through glass via (TGV) wafers​ can be used.
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    Micro-optics

    Wafer-level micro-optics are increasingly used in mobile devices to enable gesture sensing and 3D scanning, which require extreme precision. Glass-to-glass laser bonding enables miniaturized, hermetically sealed assemblies, supporting micro-optics functionality.
    Technology

    Technology

    Innovative Primoceler® glass-to-glass sealing technology is a highly efficient wafer-level process. It surpasses traditional methods like anodic bonding, fusion bonding, or epoxy encapsulation, delivering superior reliability, smaller devices, and higher yields per wafer. Review the technical details below.​

    Advantages of Primoceler® glass-to-glass sealing over other technologies​

    SCHOTT Primoceler Oy’s glass-to-glass micro bonding is a proven superior alternative to existing sealing methods including anodic bonding, direct/fusion bonding, glass frit, or epoxy (UV or thermal) encapsulation.


    Primoceler®​ Anodic bonding Direct/fusion bonding Glass frit Epoxy (UV) Epoxy (thermal)
    Hermetic Yes Yes Yes No/ In rare circumstances No No
    Sealing process No additives Silicon or metal needed; glass-glass not possible No additives Additives needed Additives needed Additives needed
    Process temperature Room temperature 440° C (824° F) 1000° C (1832° F) (no plasma); ​440° C (824° F) (with plasma) 440° C (824° F) Room temperature 200° C (392° F)
    Clean room class requirement 100/ 1000 100 10 1000 1000 1000

    Bonding principle

    SCHOTT Primoceler´s glass-to-glass sealing is done with a laser at room temperature without any additive materials.

    Primoceler® glass micro bonding

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    • Direct bonding without additive materials​
    • No gap between top and bottom substrates

    Other bonding methods​

    SCHOTT_EP_Primoceler_Gap_690x431px.jpg

    • Additive materials used for bonding
    • Gap between top and bottom substrates​
    • Controlling the gap is difficult or impossible

    Wafer-level process

    SCHOTT Primoceler’s advanced glass wafer packaging process is highly efficient and delivers high replicability, smaller device size, and more devices per wafer than conventional processes.

    Advanced packaging process​

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    1. Dies are packaged on the wafer​
    2. Laser micro bonding creates a hermetic package​
    3. Dicing of the wafer; thousands of hermetically sealed chips are ready

    Conventional packaging​ process

    SCHOTT_EP_Primoceler_Packing_overview_B_690x431px.jpg

    1. Chips produced on silicon wafers​
    2. Thousands of chips produced by dicing the wafer
    3. Every chip has to be packaged individually​
    4. Laser welding of the lid creates a hermetic packaging
    ​​

    Wireless device capability and hermetic feedthroughs​

    All-glass packaging enables production of wireless devices as well as devices with hermetic feedthroughs. On the base wafer (1), a spacer glass (2a) or an edged lid (2b) is positioned to form a cavity. This results in a hermetic package with a controlled atmosphere (3).​

    Wireless

    SCHOTT_EP_Primoceler_Bonding_A_690x431px.jpg

    Full glass design enables RF-transparency for wireless power and data transfer​

    With feedthroughs​

    SCHOTT_EP_Primoceler_Bonding_B_690x431px.jpg

    All-glass packaging with HermeS® through-glass via (TGV) wafers provides reliable electrical feedthroughs​​

    Products & expertise

    Related products​

    Hands holding large pacemaker and miniaturized implant

    Proteon™ for medical implants​

    Proteon™ is SCHOTT Primoceler Oy's brand for a new class of advanced packaging that enables the development of the next generation of life-enhancing medical implants. Manufactured using Primoceler® glass-to-glass laser sealing technology, it combines exceptional protection with miniaturized design.​

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    SCHOTT cleanroom technician inspecting glass wafer

    HermeS® through-glass via wafer​

    Glass wafer substrates with hermetically sealed, solid through-glass vias (TGV) enable ultra-miniaturized, fully hermetic sensors and MEMS devices in wafer-level chip-size packaging (WLCSP). The extremely fine-pitched vias enable reliable conduction of electrical signals and power into and out of MEMS devices.

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    About SCHOTT Primoceler Oy

    SCHOTT Primoceler Oy, a subsidiary of SCHOTT AG, was founded in 2010 and is based in Tampere, Finland. Since joining SCHOTT in 2018, Primoceler has enhanced the Electronic Packaging business unit with its revolutionary hermetic sealing technology, strengthening SCHOTT’s​ position as one of the most attractive supplier of hermetic packaging solutions worldwide.

    Want to talk directly to an expert?

    Ville Hevonkorpi

    Ville Hevonkorpi

    Head of New Venture Primoceler

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