The steam generating assembly of the present invention subjects a food product, such as a sandwich bun, to a controlled burst of low pressure steam in order to quickly and uniformly raise the temperature of the food product to its desired serving temperature or higher. A first vertically arranged column is arranged on a first side of the support frame, and a second vertically arranged column is arranged on a second opposing side, each with three modules positioned on top of each other. A diffusion solder layer is arranged between mutually aligned large-area contacts of the stacked integrated circuit chips, the diffusion solder layer extending as far as the edges of the integrated circuit chips. Then, the resin film is cured to form the mask covering the area other than the area to be removed by the etching. In the method, the layers are applied by successive dip coating techniques using solvent-based solutions and the resulting coatings can be used to coat large sized substrates which can be later cut, trimmed andor otherwise shaped and later heat treated with substantial retention of optical properties.