Method of making a multi-chip package device

A method of making a multi-chip package device comprising:

• a) providing a lead frame unit having an outer frame, and a plurality of lead frames that are surrounded by the outer frame, that are connected to each other and to the outer frame, each of the lead frames having a base seat and a plurality of leads extending from the base seat and being spaced apart from each other, the base seat having an upper surface and a bottom surface opposite to the upper surface;
• b) for each of the lead frames, electrically attaching a transistor chip onto the upper surface of the base seat, the transistor chip having a drain electrode that is electrically connected with the base seat, a plurality of source electrode pads and a gate electrode that are located at a position opposite to the drain electrode and away from the upper surface of the base seat;
• c) for each of the lead frames, attaching a circuit control chip to the upper surface of the base seat, the circuit control chip being electrically isolated from the base seat of the lead frame and being spaced apart from the transistor chip on the upper surface of the base seat of the lead frame;
• d) for the transistor chip on each of the lead frames, covering the transistor chip on the upper surface of the base seat with a main conducting part of a metal layer and electrically connecting the main conducting part with at least one of the source electrode pads of the transistor chip, the metal layer further including a leg part extending from the main conducting part;
• e) for the circuit control chip of each of the lead frames, electrically connecting the circuit control chip to the leads of the lead frame, and to another source electrode pad of the transistor chip that is not connected to the main conducting part of the metal layer, and to the gate electrode of the transistor chip;
• f) on each of the lead frames, encapsulating a part of the metal layer, the transistor chip and the circuit control chip on the upper surface of the base seat of the lead frame with an encapsulation material and forming an encapsulation layer that exposes the bottom surface of the base seat and a portion of the leg part of the metal layer, thereby obtaining a semi-product;
• and
• g) bending the portion of the leg part of the metal layer that is exposed from the encapsulation layer towards the lead frame to form a planar conducting portion, the planar conducting portion having a conducting bottom surface that is coplanar with the bottom surface of the base seat.