Power semiconductor module and power module

1. A power semiconductor module comprising: a semiconductor device;

a conductor plate having a first surface on which the semiconductor device is mounted;

a resin sealer that covers a side portion of the conductor plate and exposes at least part of the a second surface of the conductor plate that faces away from the first surface; and

a spray coated film provided on an outer surface of the resin sealer and the at least part of the second surface of the conductor plate that is exposed through the resin sealer, and

a recess is formed in the outer surface of the resin sealer, and the planar size of the recess is greater than the planar size of each flat portion that forms the spray coated film;

wherein the spray coated film is continuously disposed on the outer surface of the resin sealer, in the recess, and on the at least part of the second surface of the conductor plate that is exposed through the resin sealer, without interruption.

2. The power semiconductor module according to claim 1 , wherein an end of the recess that is closer to the conductor plate is set apart by a predetermined length from a boundary between the exposed part of the second surface of the conductor plate and the resin sealer.

3. The power semiconductor module according to claim 2 , wherein the predetermined length is greater than or equal to a distance that prevents discharge in the resin sealer even when voids are formed in the spray coated film and when the semiconductor device operates at a maximum rating.

4. The power semiconductor module according to claim 3 , wherein the predetermined length is greater than X calculated by using the following Expression (I):

X=t ∈{( V i /U i )−1}  Expression (I)

where t represents the size of a gap that is most likely to cause discharge, ∈ represents the dielectric constant of a sealing resin, U i represents a discharge initiation voltage at which discharge is initiated in the gap, and V i represents a partial discharge initiation voltage.

5. The power semiconductor module according to claim 1 , wherein the thickness of the spray coated film is greater than the depth of the recess formed in the resin sealer.

6. The power semiconductor module according to claim 1 , wherein minute protrusions and recesses are formed at least one of the lower surface of the resin sealer and the other surface of the conductor plate that is exposed through the resin sealer, and the minute protrusions and recesses are smaller than the planar size of the recess of the resin sealer.

7. The power semiconductor module according to claim 1 , wherein the resin sealer contains ceramic fillers, the ceramic fillers are exposed in the recess formed in the resin sealer, and the spray coated film is bonded to the ceramic fillers.

8. The power semiconductor module according to claim 1 , wherein the power semiconductor module further comprising:

an insulation film disposed on the spray coated film and containing ceramic fillers; and

a stress relaxation resin layer formed around the insulation film.

9. The power semiconductor module according to claim 8 , wherein the thermal conductivity of the stress relaxation resin layer is smaller than the thermal conductivity of the insulation film.

10. The power semiconductor module according to claim 1 , wherein holes in the spray coated film are impregnated with an insulating resin.

11. The power semiconductor module according to claim 1 , wherein a side surface of the recess formed in the resin sealer is an inclined surface inclined in a direction in which the planar size of the recess increases from a bottom thereof toward an opening thereof.