Self-constrained low temperature glass-ceramic unfired tape for microelectronics and methods for making and using the same

The co-sintering or firing of laminated ceramic tapes is a well-known module manufacturing method in the microelectronics industry. The term "low-temperature co-fired ceramic (LTCC)" refers to a technology for forming multilayered ceramic circuits. In this approach, a tape is formed from glass and ceramic powders uniformly dispersed in an organic binder. Typically, two or more layers of this tape are laminated together to form a circuit. To form electrical connections from one layer of tape to the next, via holes are punched through the tape and filled with a thick-film conductor paste, for example as described in U.S. Pat. No. 4,654,095 of Steinberg. A monolithic self-constrained green body tape for use in low temperature ceramic co-firing is provided. The tape contains at least two layers: one low temperature ceramic layer containing particles of a glass, a ceramic, and an organic binder, and a self-constraining layer containing a refractory ceramic and a wetting agent for the glass in the first layer. When the tape is fired at a sintering temperature of the low temperature ceramic layer, densification occurs in the z (thickness) direction, but essentially no shrinkage (less than about 1%) occurs in the x-y planes. A method for forming a multilayer green body tape using simultaneous wet on wet ceramic slurry deposition is also provided. A dense, monolithic, low temperature, co-fired, self-constrained, multicomponent structure is also provided. The structure contains at least two multilayer ceramic substrates having electronic circuit components mounted thereon or therein. Each multilayer ceramic substrate contains at least two layers with one being a self-constraining layer.