High-temperature cofired ceramic

MCM-C interconnect substrates are produced from either low-temperature cofired ceramic (LTCC) or high-temperature cofired ceramic (HTCC). Either process can produce multilayer substrates having high numbers of conductor layers (up to 100), although for most applications 2-20 layers are sufficient. The fabrication of MCM-C involves thick-film processes that have wider lines and spacings (5-20 mils) than MCM-D, but are lower in cost. 

Figure 5.6 Example of a ceramic multichip module (MCM-C) and a hybrid microcircuit. Top MCM-C fabricated from high-temperature cofired ceramic. Source Honeywell Sohd State Electronics Center. Bottom Multilayer thick-film hybrid microcircuit.

The original multilayered ceramic packages were developed around what is today known as a high-temperature cofired ceramic (HTCC). In this technology the ceramic was primarily an alumina-based... 

High-temperature cofired ceramic (HTCC) packages make use of thermal vias in the same manner as in multilayer thick-film substrates. The via-fill material used in HTCC packages is a refractory material such as tungsten or moly-manganese. 

The development of multilayer ceramics was first demonstrated in the preparation of capacitors in the late 1940s [1]. Over the following 10 years, the techniques necessary to produce multilayer high-temperature cofired ceramics (HTCC) substrates [2] were developed at American Lava and RCA, culminating in the first comprehensive description of this technology in 1961... 

Copper can be plated on the surface conductors of both high-temperature cofired ceramic (HTCC) and low-temperature cofired ceramic (LTCC) packages and substrates. On internal layers, on HTCC, the conductors must be composed of high-resistivity refractory metallization. 

Ceramic-glass composite materials may be used to economically fabricate very complex multilayer interconnection structures. The materials in powder form are mixed with an organic binder, a plasticizer, and a solvent and formed into a slurry by ball or roll milling. The slurry is forced under a doctor blade and dried to form a thin sheet, referred to as green tape or greensheet. Further processing depends on the type of material. There are three basic classes of materials high temperature cofired ceramic (HTCC), low temperature cofired ceramic (LTCC), and aluminum nitride. 

Low temperature cofired ceramic (LTCC) High temperature cofired ceramic (HTCC) Aluminum nitride... 

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