Semiconductor device covered by front electrode layer and back electrode layer

摘要

The invention prevents a semiconductor device from warping due to heat when it is used. The invention also prevents a formation defect such as peeling of a resist layer used as a plating mask and a formation defect of a front surface electrode. A source pad electrode connected to a source region is formed on a front surface of a semiconductor substrate forming a vertical MOS transistor. A front surface electrode is formed on the source pad electrode by a plating method using a resist layer having openings as a mask. The semiconductor substrate formed with the front surface electrode is thinned by back-grinding. A back surface electrode connected to a drain region is formed on the back surface of the semiconductor substrate. The front surface electrode and the back surface electrode are made of metals having the same coefficients of linear expansion, preferably copper. The front surface electrode and the back surface electrode preferably have the same thicknesses or almost the same thicknesses.

主权项

1. A semiconductor device comprising: a semiconductor substrate having a front surface and a back surface; a vertical field-effect transistor including a source region, a drain region, and a gate electrode; a first electrode covering more than 70% of the front surface of the semiconductor substrate and coupled to the source region; a second electrode covering a portion of the front surface of the semiconductor substrate and spaced apart from the first electrode, wherein the second electrode is coupled to the gate electrode; and a third electrode covering more than 90% of the back surface of the semiconductor substrate and coupled to the drain region, wherein each of the first electrode and the second electrode has a first set of electrode layers including a first electrode layer; the third electrode has a second set of electrode layers that has a composition that is different from the first set of electrode layers, wherein the third electrode includes a second electrode layer; and the first electrode layer and the second electrode layer have the same amount of thermal expansion and the thicknesses of the first electrode layer and the second electrode layer are sufficient to prevent warping of the semiconductor device.