{"id":3210,"date":"2026-07-07T01:40:09","date_gmt":"2026-07-07T01:40:09","guid":{"rendered":"https:\/\/www.fuyao-quartz.com\/?p=3210"},"modified":"2026-07-07T01:52:44","modified_gmt":"2026-07-07T01:52:44","slug":"why-bf33-glass-is-used-in-mems-devices-and-optical-packaging","status":"publish","type":"post","link":"https:\/\/www.fuyao-quartz.com\/ja\/why-bf33-glass-is-used-in-mems-devices-and-optical-packaging\/","title":{"rendered":"Why BF33 Glass Is Used in MEMS Devices and Optical Packaging"},"content":{"rendered":"

BF33 glass, also known as BOROFLOAT 33 \u30db\u30a6\u30b1\u30a4\u9178\u30ac\u30e9\u30b9<\/a>, is widely used in MEMS devices, optical packaging, wafer bonding, sensor protection, and precision glass components. For engineers and buyers working with micro-devices, optical modules, and semiconductor-related packaging, BF33 offers a useful balance of thermal stability, optical clarity, chemical durability, and process compatibility.<\/p>\n\n\n\n

Unlike ordinary soda-lime glass, BF33 is a high-performance borosilicate glass produced by a float process. This gives it good surface flatness, stable thickness control, and reliable optical quality. These features make it suitable for applications where the glass is not only a cover material, but also part of the functional package.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

What Is BF33 Glass?<\/h2>\n\n\n\n

BF33 glass is a low-expansion borosilicate glass. It is commonly selected when the application requires stable performance under temperature change, good transparency, and resistance to chemical environments. According to SCHOTT, BOROFLOAT\u00ae is a floated borosilicate glass introduced in 1993, and it is known for high transparency, thermal resistance, chemical durability, mechanical strength, and excellent flatness from microfloat production.<\/p>\n\n\n\n

In semiconductor and optical applications, BF33 can be supplied as glass wafers, thin glass sheets, windows, covers, substrates, or customized precision parts. Typical processing may include cutting, drilling, grinding, polishing, coating, cleaning, and dimensional inspection.<\/p>\n\n\n\n

Why MEMS Devices Need Special Glass Materials<\/h2>\n\n\n\n

MEMS, or micro-electromechanical systems, contain tiny mechanical and electrical structures. These devices may include pressure sensors, accelerometers, gyroscopes, microphones, micro-mirrors, microfluidic structures, and optical MEMS components.<\/p>\n\n\n\n

Because MEMS structures are small and sensitive, packaging is extremely important. The package must protect the device from dust, moisture, mechanical stress, and sometimes gas leakage, while still allowing the device to perform its sensing or optical function. SCHOTT describes MEMS packaging as requiring precise, durable protection, and notes that MEMS components often need long-term gas tightness and protection from heat damage and mechanical exposure.<\/p>\n\n\n\n

This is where BF33 glass becomes useful. It can act as a cap wafer, transparent cover, optical window, bonding substrate, or protective lid, depending on the device design.<\/p>\n\n\n\n

Key Advantages of BF33 Glass for MEMS Applications<\/h2>\n\n\n\n

1. Low Thermal Expansion<\/h3>\n\n\n\n

One major reason BF33 is used in MEMS packaging is its low coefficient of thermal expansion. In MEMS manufacturing, glass may be bonded to silicon or other substrates. If the thermal expansion mismatch is too large, stress may build up during heating, cooling, or long-term operation.<\/p>\n\n\n\n

BF33\u2019s low-expansion borosilicate composition helps reduce thermal stress compared with many common glasses. This is especially important for wafer-level packaging, pressure sensor caps, and glass-to-silicon bonding structures.<\/p>\n\n\n\n

2. Suitable for Anodic Bonding<\/h3>\n\n\n\n

Anodic bonding is a common method used to bond glass to silicon in MEMS packaging. It uses elevated temperature and voltage to create a strong bond between the glass and silicon surface.<\/p>\n\n\n\n

BF33 glass is often selected for this type of process because it is a borosilicate glass with properties suitable for glass-to-silicon bonding. SCHOTT specifically states that BOROFLOAT\u00ae and MEMpax\u00ae are flat, highly homogeneous borosilicate glasses ideally suited to anodic bonding for MEMS pressure sensor applications.<\/p>\n\n\n\n

This makes BF33 useful for pressure sensors, inertial sensors, microfluidic chips, and other MEMS structures where a stable sealed cavity is required.<\/p>\n\n\n\n

3. High Optical Transparency<\/h3>\n\n\n\n

For optical packaging, transparency is not optional. The glass may need to transmit visible light, infrared light, or specific wavelengths used in optical sensing, imaging, inspection, projection, or communication systems.<\/p>\n\n\n\n

BF33 glass provides good optical clarity and low distortion, making it suitable for windows, covers, and optical interfaces. SCHOTT describes BOROFLOAT\u00ae as having excellent clarity and distortion-free light transmission across a wide spectrum.<\/p>\n\n\n\n

In optical MEMS, such as MEMS mirrors, scanners, and micro-optical modules, the glass package must protect the device while allowing light to pass through with minimal optical loss or distortion.<\/p>\n\n\n\n

4. Good Surface Flatness<\/h3>\n\n\n\n

Flatness is important for wafer bonding, optical packaging, and precision assembly. If a glass wafer has poor flatness, it may cause bonding defects, uneven sealing, optical distortion, or alignment issues.<\/p>\n\n\n\n

Because BF33 is made by a float glass process, it can provide better surface consistency than many mechanically formed glass materials. For wafer-level packaging, this helps improve bonding uniformity and device reliability.<\/p>\n\n\n\n

5. Chemical Durability<\/h3>\n\n\n\n

MEMS and optical packaging may be exposed to cleaning chemicals, process residues, moisture, or working environments that require long-term stability. BF33 borosilicate glass has good chemical durability, which helps protect sensitive devices and maintain stable package performance.<\/p>\n\n\n\n

SCHOTT notes that BOROFLOAT\u00ae has high chemical durability and resistance to acids and organic substances, making it suitable for demanding industrial applications.<\/p>\n\n\n\n

This is useful in sensors, laboratory chips, microfluidic devices, analytical instruments, and industrial optical modules.<\/p>\n\n\n\n

6. Mechanical Strength and Scratch Resistance<\/h3>\n\n\n\n

In many applications, the glass cover or wafer must survive handling, assembly, dicing, bonding, and operation. BF33 offers good mechanical strength and abrasion resistance compared with ordinary glass materials.<\/p>\n\n\n\n

For MEMS packaging and optical windows, surface damage may affect sealing performance, optical transmission, or long-term reliability. Therefore, glass strength, edge quality, surface finish, and cleaning process should all be considered during custom manufacturing.<\/p>\n\n\n\n

BF33 Glass in Optical Packaging<\/h2>\n\n\n\n

Optical packaging refers to the use of glass, ceramic, metal, or other materials to protect and align optical components. BF33 glass can be used in:<\/p>\n\n\n\n

    \n
  • Optical sensor windows<\/li>\n\n\n\n
  • MEMS mirror covers<\/li>\n\n\n\n
  • Laser module windows<\/li>\n\n\n\n
  • Photodetector covers<\/li>\n\n\n\n
  • Camera and inspection windows<\/li>\n\n\n\n
  • Optical communication packages<\/li>\n\n\n\n
  • Micro-optical device lids<\/li>\n\n\n\n
  • Transparent wafer-level packages<\/li>\n<\/ul>\n\n\n\n

    In these applications, BF33 is valued because it combines optical transparency with thermal and mechanical stability. For optical MEMS mirrors, SCHOTT notes that MEMS mirrors require protection from moisture and dust particles while maintaining a high-performance optical interface, and lists BOROFLOAT\u00ae among suitable ultra-thin glasses for mirror substrates.<\/p>\n\n\n\n

    BF33 Glass Wafer Design Considerations<\/h2>\n\n\n\n

    When selecting BF33 glass wafers or custom BF33 parts, engineers should consider more than just material name. Important specifications include:<\/p>\n\n\n\n

    \u30d1\u30e9\u30e1\u30fc\u30bf<\/th>Why It Matters<\/th><\/tr>
    Wafer diameter<\/td>Must match device wafer or bonding equipment<\/td><\/tr>
    \u539a\u3055<\/td>Affects strength, optical path, package height, and processing stability<\/td><\/tr>
    TTV<\/td>Important for bonding uniformity and wafer-level processing<\/td><\/tr>
    Bow and warp<\/td>Affects alignment, bonding, and lithography compatibility<\/td><\/tr>
    Surface roughness<\/td>Important for bonding, coating, and optical performance<\/td><\/tr>
    \u30a8\u30c3\u30b8\u306e\u54c1\u8cea<\/td>Reduces chipping and cracking during handling<\/td><\/tr>
    Coating requirement<\/td>AR, conductive, reflective, or protective coatings may be needed<\/td><\/tr>
    Cleaning grade<\/td>Important for semiconductor and optical applications<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    For MEMS and optical packaging, the final performance depends not only on the glass material, but also on precision processing, surface quality, dimensional control, and cleanliness.<\/p>\n\n\n\n

    BF33 Glass vs Fused Silica<\/h2>\n\n\n\n

    BF33 glass and fused silica are both used in precision applications, but they are not the same material.<\/p>\n\n\n\n

    BF33 is usually chosen when the project needs borosilicate glass with good flatness, low expansion, reliable optical quality, and suitability for bonding or packaging. Fused silica is often selected when the application requires higher UV transmission, higher purity, or better high-temperature performance.<\/p>\n\n\n\n

    For many MEMS packaging applications, BF33 can be more cost-effective and easier to process than fused silica. For high-end optical or UV applications, fused silica may still be preferred. The right choice depends on wavelength range, thermal requirements, bonding method, surface quality, and budget.<\/p>\n\n\n\n

    Typical Applications of BF33 Glass<\/h2>\n\n\n\n

    BF33 glass is commonly used in:<\/p>\n\n\n\n

      \n
    • MEMS pressure sensor caps<\/li>\n\n\n\n
    • Glass-to-silicon bonded wafers<\/li>\n\n\n\n
    • Optical MEMS packages<\/li>\n\n\n\n
    • Micro-mirror covers<\/li>\n\n\n\n
    • Transparent sensor windows<\/li>\n\n\n\n
    • Wafer-level chip size packaging<\/li>\n\n\n\n
    • Microfluidic glass components<\/li>\n\n\n\n
    • Optical inspection windows<\/li>\n\n\n\n
    • Precision glass substrates<\/li>\n\n\n\n
    • Semiconductor and laboratory glass parts<\/li>\n<\/ul>\n\n\n\n

      \u7d50\u8ad6<\/h2>\n\n\n\n

      BF33 glass is widely used in MEMS devices and optical packaging because it offers a strong combination of low thermal expansion, good optical transparency, chemical durability, mechanical strength, and excellent flatness. For MEMS pressure sensors, optical MEMS mirrors, wafer-level packages, and precision optical windows, these properties help improve device protection, bonding reliability, and optical performance.<\/p>\n\n\n\n

      When sourcing BF33 glass wafers or custom BF33 components, buyers should pay close attention to wafer size, thickness, TTV, surface finish, edge quality, coating requirements, and cleanliness. A well-designed BF33 glass component can play an important role in protecting sensitive MEMS structures and improving long-term package reliability.<\/p>\n\n\n

      \n
      \n
      \n

      Is BF33 glass suitable for anodic bonding?<\/h3>\n
      \n\n

      Yes. BF33 borosilicate glass is commonly used for glass-to-silicon bonding applications, including MEMS sensor packaging. Its low thermal expansion and borosilicate composition make it suitable for many anodic bonding processes.<\/p>\n\n<\/div>\n<\/div>\n

      \n

      Can BF33 glass be used as an optical window?<\/h3>\n
      \n\n

      Yes. BF33 glass provides good transparency and optical clarity, making it suitable for optical windows, sensor covers, inspection windows, and optical MEMS packaging.<\/p>\n\n<\/div>\n<\/div>\n

      \n

      What should buyers check when ordering BF33 glass wafers?<\/h3>\n
      \n\n

      Buyers should check diameter, thickness, TTV, bow, warp, surface roughness, edge finish, coating requirements, cleanliness level, and packaging method. For MEMS and optical packaging, these details can directly affect bonding yield and device performance.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

      BF33 glass, also known as BOROFLOAT 33 borosilicate glass, is widely used in MEMS devices, optical packaging, wafer bonding, sensor protection, and precision glass components. For engineers and buyers working with micro-devices, optical modules, and semiconductor-related packaging, BF33 offers a useful balance of thermal stability, optical clarity, chemical durability, and process compatibility. Unlike ordinary soda-lime […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1],"tags":[1627,923,1676,680,1352,615,1677,1678,785,1622],"class_list":["post-3210","post","type-post","status-publish","format-standard","hentry","category-industry-news","tag-anodic-bonding","tag-bf33-glass","tag-borofloat-33","tag-borosilicate-glass","tag-glass-wafer","tag-mems-devices","tag-mems-packaging","tag-optical-packaging","tag-optical-window","tag-wafer-bonding"],"_links":{"self":[{"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/posts\/3210","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/comments?post=3210"}],"version-history":[{"count":2,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/posts\/3210\/revisions"}],"predecessor-version":[{"id":3212,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/posts\/3210\/revisions\/3212"}],"wp:attachment":[{"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/media?parent=3210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/categories?post=3210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fuyao-quartz.com\/ja\/wp-json\/wp\/v2\/tags?post=3210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}