Ceramic and Glass Substrates

The demand for miniaturization and for increased reliability of electronic equipment is responsible for the increased use of ceramic and glass substrates. These materials serve as the base upon which electrical components such as resistors, capacitors, and conductors are... 

Poon, C. Y. andBhhushan, B., Surface Roughness Analysis of Glass-Ceramic Substrates and Finished Magnetic Disks, and Ni-P Coated Al-Mg and Glass Substrates," Wear, Vol. 190, 1995,pp. 89-109. 

One of the simplest, albeit least discussed, chemiresistors is the mercury vapor sensor. The heart of this device is a thin (7-40 nm) film of gold evaporated on a ceramic or glass substrate. At such thicknesses, the films are continuous, with the resistivity between 300 and l,500Qcm. The sensors are usually connected as a pair in a DC bridge configuration with one sensor acting as the reference. 

The PTCDI films with thickness of 100 nm were prepared by laser evaporation in vacuum of 10 Pa. The LGN-703 infrared C02-laser with output power of 40 W was used for evaporation of powdered PTCDI target. The products of evaporation were deposited onto the glass-ceramic and mica substrates at 20°C (cold) and 150°C (hot). The glass-ceramic substrates contain a preliminary formed interdigital system of nickel electrodes. 

Microstractured reactors have been fabricated from a variety of substrates, including silicon, quartz, metals, polymers, ceramics, and glass. The choice of substrate is largely dependent on the following parameters ... 

The smoothness of a ceramic depends upon its microstructure and density. A high-density body composed of small grains will form a smoother substrate than a ceramic consisting of larger grains (see Fig. 2.49). As-fired alumina substrates with a 2 /tin. surface finish are reported," and glass substrates with a surface smoothness of 1/4 /tin. (60 A) are commercially available (Coming 7059). 

Ceramic frits and metal solders are also used to seal IC packages when hermetic seals are required. The ceramic is applied to the substrates out of a suspension. The solvent is evaporated and the binder burned out. The cover is then put in place and the glass frit is melted to produce the bond. Properties of the ceramic and glass are given in Table 3. 

Metal powder—glass powder—binder mixtures are used to apply conductive (or resistive) coatings to ceramics or metals, especially for printed circuits and electronics parts on ceramic substrates, such as multichip modules. Multiple layers of aluminum nitride [24304-00-5] AIN, or aluminay ceramic are fused with copper sheet and other metals in powdered form. The mixtures are appHed as a paste, paint, or slurry, then fired to fuse the metal and glass to the surface while burning off the binder. Copper, palladium, gold, silver, and many alloys are commonly used. 

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