Aluminum nitride electronic packaging

Aluminum nitride has received attention as an alternative to Si02 dielectric layers in microelectronic circuits because of its high dielectric strength. Being a refractory ceramic with high thermal conductivity, AIN is useful for electronics packaging. There are also uses for AIN as a piezoelectric material because of its high surface acoustic wave velocity. 

Aluminum nitride Packaging material for electronic devices, dielectric layers. 

Many of the applications of AIN require it to be in consolidated in the form of substrates or crucibles. It is an electrical insulator and has a high thermal conductivity (better than Fe), which makes it attractive for use in electronic packaging. Aluminum nitride crucibles are used to contain metal melts and molten salts. 

HTCC is an all-inclusive term to describe ceramic substrates that are consolidated at temperatures above about 1000°C. Applied to electronic packaging, this descriptor includes aluminum oxide, aluminum nitride (AIN), and a variety of other developmental or seldom-used materials. Until recently, discriminating between HTCC and low-temperatme cofired ceramics (LTCC) was elementary, as the firing temperatures differed by roughly 600°C. To confoimd that difference, an intermediate-firing multilayer ceramic, or medimn-temperature cofired ceramic (MTCC), has recently been introduced. Details on the processing and properties of this material will be discussed in Section 6.2 and Section 6.4. 

Alumina, aluminum nitride, silicon carbide Electronic substrates, packaging... 

When AIN was introduced for electronic packaging applications in 1985 it was considered inconsistent in properties. This inconsistency was due to problems with the AIN powders used to make sintered products. The powders were made by either of two methods direct nitridation of aluminum metal in a nitrogen gas atmosphere or carbothermal reduction of alumina, which involves the decomposition of the reaction product of aluminum trichloride with ammonia. The first process was cheaper, but the resultant powders were not especially well suited to materials for electronic applications. The carbothermal process produces powders of greater uniformity and purity, with greater control over size and shape, than the nitridation process, and is the more widely used process today." ... 

In addition to uses in electronic packaging, aluminum nitride is valuable wherever high strength and high thermal conductivity are needed. Examples are as crncibles for aluminum melting, for baUistic armor, and for aluminum resistant refractory ware. 

W. Minehan, W. Weidner, R. Jensen, R. Spielbelberger, and W. Jacobsen, Fabrication, Assembly, and Characterization of Stacked Multichip Modules Using Hot Pressed, Co-fired Aluminum Nitride, Int. J. Microcircuits and Electronic Packaging, vol. 17, no. 4, 4th quarter 1994. 

Developed to provide improved thermal management for today s smaller, faster electronic devices, silica coated aluminum nitride is a highly thermally conductive filler material used in semiconductor molding compounds. Molding compounds filled with this material provide the potential to improve reliability when compared to standard and non-metal-enhanced packages. Silica coated aluminum nitride also provides the potential to enhance functionality, power, heat dissipation and performance, while lowering system costs. 

N Iwase, T Yanazawa, M Nakahashi, K Shinozaki, A Tsuge. Aluminum nitride multi-layer pin grid array packages. 37th Electronic Components Conference, IEEE CHMT, 384-391 (1987). 

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