Semiconductor device including Schottky barrier diode and power MOSFETs and a manufacturing method of the same
In a non-insulated DC-DC converter having a circuit in which a power MOS•FET high-side switch and a power MOS•FET low-side switch are connected in series, the power MOS•FET low-side switch and a Schottky barrier diode to be connected in parallel with the power MOS•FET low-side switch are formed within one semiconductor chip. The formation region SDR of the Schottky barrier diode is disposed in the center in the shorter direction of the semiconductor chip, and on both sides thereof, the formation regions of the power MOS•FET low-side switch are disposed. From the gate finger in the vicinity of both long sides on the main surface of the semiconductor chip toward the formation region SDR of the Schottky barrier diode, a plurality of gate fingers are disposed so as to interpose the formation region SDR between them.
1. A method of forming a semiconductor device, comprising:
(a) preparing a semiconductor wafer having a semiconductor device forming region,
wherein the semiconductor device forming region includes a first long side, a second long side located on the opposite side of the first long side, a first short side and a second short side located on the opposite side of the first short side,
wherein a schottky barrier diode is formed in a first region of the semiconductor device forming region and includes an anode and a cathode,
wherein a plurality of power MOSFETs are formed in a plurality of second regions of the semiconductor device forming region and respectively include a gate electrode, a source region and a drain region,
(b) forming an insulating film over the semiconductor device forming region;
(c) forming a metal layer over the insulating film; and
(d) forming a first metal layer and a second metal layer by patterning the metal layer;
wherein the first region is arranged between the first long side and the second long side,
wherein the plurality of second regions are arranged along the first long side, and are arranged between the first long side and the first region,
wherein the first metal layer is connected to the gate electrodes, and includes a first finger portion and a second finger portion,
wherein the first finger portion extends along the first long side, and the second finger portion extends along the first short side and the second finger portion is arranged between the plurality of second regions,
wherein the second metal layer is connected to the source regions in the plurality of second regions and the anode in the first region, and
wherein a first length of the first region along the first long side is larger than a second length of the first region along the first short side.
2. A method of forming a semiconductor device according to the claim 1 , further comprising:
further second regions having further power MOSFETs each including a further gate electrode, a further source region and a further drain region,
wherein, in the direction along the first short side, the first region is arranged between the second region arranged near the first long side and the further second region arranged near the second long side.
3. A method of forming a semiconductor device according to the claim 1 ,
wherein the first metal layer further includes a third finger portion and a fourth finger portion,
wherein the third finger portion extends along the second long side, and the fourth finger portion extends along the first short side and the fourth finger portion is arranged between the plurality of further second regions, and
wherein the second metal layer is connected to the source regions in further second regions.
4. A method of forming a semiconductor device according to the claim 1 ,
wherein each of the gate electrodes is formed in grooves formed in the semiconductor wafer.
5. A method of forming a semiconductor device according to the claim 1 ,
wherein each of the gate electrodes includes a poly silicon film, and
wherein the metal layer includes an aluminum film.