Semiconductor chip and semiconductor device including a copper pillar and an intermediate layer and a concave portion formed at one end surface of the copper pillar

A semiconductor chip comprising:

• a semiconductor layer having a first surface;
• a first insulating layer formed at the first surface of the semiconductor layer;
• a conductive layer formed on the first insulating layer, the conductive layer made of a metal mainly containing Cu;
• a second insulating layer formed on the first insulating layer, the second insulating layer covering the conductive layer, the second insulating layer having an opening from which a part of the conductive layer is exposed;
• a Copper pillar extending in a thickness direction such that the Copper pillar is formed over the second insulating layer and the conductive layer, the Copper pillar made of a metal mainly containing Cu and electrically connected to the conductive layer through the opening;
• an intermediate layer formed between the conductive layer and the Copper pillar, the intermediate layer made of a material having a linear expansion coefficient smaller than a linear expansion coefficient of the conductive layer and smaller than a linear expansion coefficient of the Copper pillar;
• and
• a concave portion formed at one end surface of the Copper pillar, wherein the concave portion has a bottom surface opposed to the opening in the thickness direction and a side surface which extends upwardly in a convex arc shape from the bottom surface in a cross section, and wherein
• an acute angle between a tangent line of a surface of the convex arc shape and a surface of the concave portion becomes steeper as the tangent line becomes closer to a side edge of the Copper pillar in a cross section.