Abstract: In a method for forming a sintered silver coating film, for use as a heat spreader, on a semiconductor substrate or a semiconductor package, a coating film of an ink or paste containing silver nanoparticles is formed on one surface of the semiconductor substrate or the substrate package. Further, the coating film is sintered by heating the coating film under an atmosphere of a humidity of 30% to 50% RH (30° C.) by a ventilation oven.

Abstract: A plasma processing method in which a high-frequency power is supplied to a processing chamber in which an object to be processed is mounted, thereby producing a plasma in the processing chamber, and the object is processed in an atmosphere of the plasma, wherein the high-frequency power is subjected to modulation by a low-frequency power. In one embodiment a plasma is produced in a processing chamber by using an electric power with a direction of current changed with passing of time, and the object to be processed is processed in an atmosphere of the plasma, wherein a power having a basic frequency is subjected to frequency modulation with a frequency equal to n-times (n=an integer) the basic frequency. In a plasma processing apparatus of the invention, while a process gas is supplied to a processing chamber via a first gas introducing hole formed in an electrode, an object to be processed, which is held on an opposed electrode, is subjected to plasma processing.