NOVELTY - Forming a fuel cell assembly involves providing an interconnect structure (102) having at least one flow channel; depositing a sacrificial material (110) into the flow channel(s); depositing an electrode (112) and/or an electrolyte material (114) on the interconnect structure and the sacrificial material; and processing the fuel cell assembly so as to remove the sacrificial material.    USE - For forming fuel cell assembly, such as solid oxide fuel cells, proton exchange membrane or solid polymer fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells, alkaline fuel cells, direct methanol fuel cells, regenerative fuel cells, zinc air fuel cells, and protonic ceramic fuel cells, useful in applications including large-scale power generation, distributed power and automobiles.    ADVANTAGE - The sacrificial material fills the fluid flow channels and provides a temporary substrate for deposition of electrode or electrolyte materials. The use of the interconnect portion as a support structure for cell fabrication provides a low-cost, large-area fabrication mechanism allowing for layer-by-layer deposition upon the interconnect portion.    DETAILED DESCRIPTION - Forming a fuel cell assembly involves providing an interconnect structure (102) having at least one flow channel (108); depositing a sacrificial material (110) into the flow channel(s); depositing an electrode (112) and/or an electrolyte material (114) on the interconnect structure and the sacrificial material; and processing the fuel cell assembly so as to remove the sacrificial material. The electrode and/or electrolyte material is deposited by sputtering, sol-gel, tape calendaring, jet vapor deposition, expanding thermal plasma deposition, electrophoretic deposition, chemical vapor deposition (CVD), plasma enhanced CVD and/or physical vapor deposition (PVD). The fuel cell assembly is processed by heating, cooling, chemical etching, ablation or by dissolution.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of interconnect supported planar fuel cell.    Interconnect structure (102)    Sacrificial material (110)    Electrode (112)    Electrolyte material (114)    Cathode layer (116)