Resistor cofire

The LTCC technology offers tire possibility of fabricating resistors and capacitors on inner layers that can be cofired along with the other circuitry. This saves a tremendous amoimt of area over conventional circuits and increases the packaging density by orders of magnitude. Consider that every input and output of a digital circuit needs a pull-up or pull-down resistor. In a complex circuit, this can require hundreds or even thousands of resistors. 

Furthermore, the technique of laminating and cofiring more than two types of ceramic sheet with different dielectric characteristics, and the process of forming a resistor by cofiring are also well known [17]. 

Most often, the assembly is cofired at a temperature around 850°C, which imposes the replacement of alumina by a mixture of alumina and a vitreous phase. Several studies are undertaken to insert resistors and capacitors in different levels, thus achieving a truly three-dimensional circuit... 

---