Semiconductor device and flat electrodes

A semiconductor device comprising:

• a first semiconductor pellet having at least a flat electrode;
• and
• a second semiconductor pellet having at least a protruded electrode directly connected with said flat electrode;
• wherein a main component of a conductive material of said protruded electrode is the same as a main component of a conductive material of said flat electrode, and the hardness of said protruded electrode is higher than the hardness of said flat electrode,
• wherein the hardness of said protruded electrode is 20 Hv (Vickers hardness) or more higher than the hardness of said flat electrode.

A semiconductor device comprising:

• a first semiconductor pellet having at least a flat electrode;
• and
• a second semiconductor pellet having at least a protruded electrode directly connected with said flat electrode;
• wherein a main component of a conductive material of said protruded electrode is the same as a main component of a conductive material of said flat electrode, and the hardness of said protruded electrode is higher than the hardness of said flat electrode,
• wherein said flat electrode is a metal electrode and said protruded electrode is an alloy electrode, said alloy consisting essentially of said metal.

A semiconductor device comprising:

• a first semiconductor pellet having at least a flat electrode;
• and
• a second semiconductor pellet having at least a protruded electrode directly connected with said flat electrode;
• wherein a main component of a conductive material of said protruded electrode is the same as a main component of a conductive material of said flat electrode, and the hardness of said protruded electrode is higher than the hardness of said flat electrode,
• wherein said flat electrode is made of a conductive material subjected to an annealing treatment so as to decrease the hardness of said flat electrode.

A semiconductor device comprising:

• a first semiconductor pellet having at least a flat electrode;
• and
• a second semiconductor pellet having at least a protruded electrode directly connected with said flat electrode;
• wherein a main component of a conductive material of said protruded electrode is the same as a main component of a conductive material of said flat electrode, and the hardness of said protruded electrode is higher than the hardness of said flat electrode,
• wherein a thickness of said flat electrode is sufficient to prevent the tip portion or me protruded electrode from penetrating through the flat electrode.

A semiconductor device comprising:

• a first semiconductor pellet having at least a flat electrode;
• and
• a second semiconductor pellet having at least a protruded electrode directly connected with said flat electrode;
• wherein a main component of a conductive material of said protruded electrode is the same as a main component of a conductive material of said flat electrode, and the hardness of said protruded electrode is higher than the hardness of said flat electrode,
• wherein at least one of said protruded electrode and said flat electrode is a plated electrode so as to cause the difference between the hardness of said flat electrode and said protruded electrode.