Semiconductor device with emitter contact holes in a first layer not overlaid by emitter through holes in a second layer
View Patent ↗Emitter contact holes formed under emitter electrodes in a first layer and emitter through holes formed thereon are arranged so as not to overlap each other, and, for each emitter electrode, the multiple emitter contact holes and the multiple emitter through holes are provided so as to be separated from each other. Thereby, the top surface of an emitter electrode in a second layer is influenced by at most only a level difference of each emitter through hole formed in an insulating film having a larger thickness, and thus the flatness of the top surface of the emitter electrode in the second layer is improved. Accordingly, fixation failure of a metal plate can be avoided.
1. A semiconductor device comprising:
a semiconductor substrate of a first general conductivity type configured to operate as a collector region;
a base region of a second general conductivity type formed on the substrate;
an emitter region of the first general conductivity type formed in a surface portion of the base region to form a lattice pattern so that islands of the base region are defined in the surface portion by the lattice pattern as a matrix in plan view of the semiconductor device;
a first insulating film disposed on the emitter region and the islands of the base region and having a plurality of base contact holes standing on corresponding islands of the base region and a plurality of emitter contact holes standing on the emitter region;
a plurality of first base electrodes of a strip form, each of the first base electrodes being disposed on and in contact with a column of the islands of the matrix through corresponding base contact holes;
a plurality of first emitter electrodes of a strip form, each of the first emitter electrodes being disposed on and in contact with the emitter region through corresponding emitter contact holes;
a second insulating film disposed on the first base electrodes and the first emitter electrodes and having a plurality of base through holes standing on base contact holes that are located at ends of the columns of the matrix and a plurality of emitter through holes that do not overlay the emitter contact holes in the plan view of the semiconductor device;
a second base electrode disposed on the second insulating film so as to overlay the base through holes and be electrically in contact with the first base electrodes through the base through holes;
a second emitter electrode disposed on the second insulating film so as not to overlap the base through holes and be electrically in contact with the first emitter electrodes through the emitter through holes, the second base electrode being smaller than the second emitter electrode.
2. The semiconductor device of claim 1 , further comprising a metal plate fixed on the second emitter electrode with a conductive adhesive.
3. The semiconductor device of claim 1 , wherein each of the first base electrodes is in contact with all of the islands of the base region in a corresponding column of the matrix.
4. The semiconductor device of claim 1 , wherein an area of the second base electrode is not more than a third of an area of the second emitter electrode.
5. The semiconductor device of claim 2 , wherein the conductive adhesive comprises a solder or a silver paste.