Rectifier and method

DETAILED DESCRIPTION It is an object of the present invention to provide an improved structure and method for a solid state device, particularly a semiconductor diode suitable for use in vehicle applications.
It is a further objective to provide such employing a minimum number of piece parts and inexpensive materials and construction while still having adequate lead pull strength and improved temperature and power cycling tolerance.
The foregoing and other objects and advantages are provided by the combination comprising, (i) a metallic base with opposed first and second major faces and a cavity extending into the base from the first face, wherein the cavity has a bottom and a side extending between the bottom and the first face, wherein the bottom of the cavity has a central die bond region for receiving a semiconductor die and a peripheral region located between the central region and the side of the cavity, (ii) a semiconductor die with one face centrally mounted on the die bond region, (iii) a metallic electrode attached to an opposed, upper, face of the semiconductor die and extending away from the base, (iv) an inclined wall secured to or integral with the base, located in the peripheral region between the die bond region and the side of the cavity, and extending upwardly and outwardly from the bottom of the cavity part way toward the first surface, and (v) an encapsulation in the cavity covering edges of the semiconductor die and enclosing the inclined wall.
It is desirable that the inclined wall be integral with the base, that the root of the wall be located at about the same elevation in the cavity as the die bond region or in close proximity thereto, and that the top of the inclined wall extend above the upper surface of the die.
The metallic electrode has a flattened (nail-head) portion in electrical contact with the upper face of the rectifier die.
In general it is desirable that the top of the wall be about level with the upper surface of the lead nail-head.
It is desirable that the wall incline outwardly at about fifteen degrees with respect to the normal to the die bond region