Frit bonding

Packaging was designed to thermally isolate the device while maintaining electrical and fluid interconnects. The first step was to protect the device from mechanical shock by using spacer chips. Glass-frit bonding techniques were used to bond the chips to the reactor. Low-pressure vacuum packaging and... 

In order to be protected against environmental interference, microelectronic or microfabricated chips must be enclosed into specific packages. For some micromechanical sensors, cap wafers with etched cavities are attached hermetically onto the device wafers using anodic, eutectic, or glass frit bonding. 

Two approaches were investigated to provide selective encapsulation for surface-micromachined pressure sensor devices [9]. The first method uses a glass-frit-bonded bulk micromachined silicon cap wafer, and the second method uses a patterned polymeric gel-like material in the assembly area to create this dam. 

Frit bonding is the most common method, but there are several advantages to reactive bonding. First, very small amounts of additive are needed, which means that the electrical resistivity of the conductor is kept as low as possible. Second, the surface of the conductor is nearly pure metal, which enhances the attachment of thin Au or A1 wires during wire bonding. Some thick-film conductor compositions are termed mixed bonded and these contain a glass frit together with a mixture of oxides. 

Figure 3-3 Schema of low temperature type thick film metallization of alumina substrates (1) Frit bond type and (2) chemical bond type.

Frit bonding, which is totally dependent on the glass-substrate interaction... 

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