The applied glass layer reliably protects the function of the “passivating” the p-n-junction. At the same time, it may serve as hermetic housing of the discrete device.
Passivation glass powders feature specially developed material compositions. One of the key properties is a particularly high insulation resistance achieved by limiting the alkali content (particularly Na+) to a minimum. This is guaranteed by using only the highest grade raw materials as well as special manufacturing procedures.
To avoid stress in the finished part as well as the formation of cracks, the coefficients of thermal expansion of the passivation glass and the other semiconductor components must be matched as closely as possible. Special semiconductors also require fine tuning with respect to the surface load of the glass. SCHOTT offers different glass compositions to accomplish the best match possible.
- Comprehensive assortment of different glass compositions for various semiconductor and varistor types
- Lead-free solutions for all common passivation applications
- Supply of highest material purity with lowest alkaline content by choosing only the highest grade raw materials, tightly controlled melting as well as special grinding processes
- Sinter glass diodes and rectifiers
- Wafer passivation e.g for thyristors and diodes
- Glazing of high-voltage varistors
Glass powders are manufactured in two steps:
The raw glass is first melted in specially designed aggregates
The glass ribbons are ground into fine powders of different grain size distribution.
Our customers process our passivation glass powders in different ways. For the manufacturing of sintered glass diodes, a slurry of glass powder and deionized water is applied to the diode body before sintering it in a furnace. For wafer passivation, an organic suspension is applied by spinning, doctor blading, sedimentation, electrophoresis or screen printing.
Features / Specifications
Passivation glasses are offered in various individual specifications due to diversified glass systems, see table below.
All passivation glasses are supplied as glass powder and are available in different grain sizes.
Forms of Supply and Product Packaging
Our standard packaging consists of sealed PE-Bags in cardboard drums. For alternative packaging solutions please contact us.
SCHOTT passivation glasses: