Power semiconductor module and method of manufacturing the same
View Patent ↗A power semiconductor module and a method of manufacture thereof includes a lead frame carrying lead having inner and outer lead portions. The outer lead portions, which are connected by soldering to semiconductor chips simultaneously, eliminate the need for using bonding wires. Since no bonding wire is used for connecting the leads and the semiconductor chips, a sufficient current capacity is obtained. The bonding between an insulating circuit board and the semiconductor chips and the bonding between the semiconductor chips and the leads can be made simultaneously in a single step of reflow-soldering. As a result, the mounting time can be shortened and the power semiconductor module can be manufactured more efficiently.
1. A power semiconductor module for mounting on a control circuit board of a main apparatus, the power semiconductor module comprising:
at least one power semiconductor chip;
leads having outer lead portions for connecting to the control circuit board of the main apparatus and inner lead portions connected to the at least one semiconductor chip;
a terminal casing housing part of the leads; and
an insulating circuit board housed in the terminal casing,
wherein one major surface of the insulating circuit board forms a radiator plane,
wherein the at least one semiconductor chip is mounted on another major surface, on a side opposite to the radiator plane, of the insulating circuit board,
wherein the inner lead portions are connected to the at least one semiconductor chip on the another major surface, on the side opposite to the radiator plane, of the insulating circuit board,
wherein the terminal casing comprises a main body and a pair of fastener mounting plates extending in the opposite directions from the main body thereof to facilitate mounting of a cooling fin such that the radiator plane of the insulating circuit board is brought into contact with the cooling fin,
wherein each of the fastener mounting plates includes a fastener insertion hole, through which a fastener is insertable,
wherein the terminal casing is filled with a thermosetting resin that hardens for insulating sealing, and
wherein the radiator plane of the insulating circuit board protrudes outwardly beyond a contact plane formed by the fastener mounting plates to enable the radiator plane of the insulating circuit board to make contact with the cooling fin.
2. The power semiconductor module according to claim 1 , wherein the at least one semiconductor chip is surface-mounted on the insulating circuit board with a brazing or solder and the inner lead portions are surface-mounted on the at least one semiconductor chip with a brazing or solder.
3. The power semiconductor module according to claim 1 , wherein slits are disposed in the thin portions of the fastener mounting plates.
4. The power semiconductor module according to claim 1 , wherein each of the fastener mounting plates has a boss protruding therefrom.
5. The power semiconductor module according to claim 1 , wherein the terminal casing comprises at least one protrusion protruding toward the insulating circuit board in bonding areas between the terminal casing and the insulating circuit board, to enable the thermosetting resin to flow around the at least one protrusion into a gap between the terminal casing and the insulating circuit board.
6. The power semiconductor module according to claim 1 , wherein the terminal casing includes an adhesion strengthening structure that strengthens the adhesion of the thermosetting resin.
7. The power semiconductor module according to claim 1 , wherein:
the outer lead portions are adapted to be surface-mounted on the control circuit board with a solder on the side opposite to the side of the radiator plane, and
at least one protrusion is formed at least on the surface that is adapted to face the control circuit board, of any of the terminal casing and the fastener mounting plates, to secure a predetermined solder thickness for soldering the outer lead portions to the control circuit board.
8. The power semiconductor module according to claim 1 , wherein the outer lead portions are adapted to be surface-mounted on the control circuit board by soldering with a solder on the side opposite to the side of the radiator plane.
9. The power semiconductor module according to claim 1 , wherein at least one power semiconductor chip comprises two or more semiconductor chips having an equal thickness are mounted on the insulating circuit board.
10. The power semiconductor module according to claim 1 , wherein a fastener is insertable through the fastener insertion hole for fastening the power semiconductor module and the control circuit board to the cooling fin.
11. The power semiconductor module according to claim 2 , wherein the inner portions of the lead frames soldered with a solder include protrusions that protrude toward the solder.
12. The power semiconductor module according to claim 2 , wherein polyimide layers are formed on the at least one semiconductor chip except on electrodes thereof.