Method for flat firing aluminum nitride/tungsten electronic modules

A method and apparatus for flattening a ceramic body comprised primarily of an aluminum nitride system having a liquid phase additive necessary for low temperature sintering during a firing thereof is disclosed. The ceramic body is referred to as an aluminum nitride multilayer ceramic (AlN MLC). The method and apparatus include a support tile having a first coating on a contact surface thereof, the AlN MLC for being placed upon the contact surface of the support tile. A load flattening tile having a second coating on a contact surface thereof is provided, the load flattening tile for being placed with its coated surface upon and in contact with the AlN MLC. Lastly, a furnace is provided for heating the support tile, AlN MLC, and load flattening tile at temperatures greater than 1500 DEG C. for an amount of time necessary to flatten the ceramic body to a desired degree of flatness, wherein the first coating and the second coating of the support tile and the load flattening tile, respectively, react with the AlN MLC for quenching the liquid phase of the ceramic body to prevent a sticking of the support tile and the load flattening tile to the AlN MLC during a flattening process.