Abstract The present invention is a mechanism for packaging semiconductor chip which provides ease of assembling and high positioning precision with improved mechanical, electrical and thermal performance. The present invention adopts a die pad frame for supporting the semiconductor chip and a separate lead frame for connection to center part of the semiconductor chip. The semiconductor chip is fixed on the die pad using silver paste, the lead frame conductors are then placed on top of the chip, and the lead frame and the die pad frame containing the chip are assembled with the positioning protrusions of the die pad frame locked and secured by the positioning openings of the lead frame. Subsequently the bonding terminals on the chip are connected to the lead conductors with short gold wires. The frames locking method does not require high precision positioning machines, thereby reducing the assembly cost. The packaged chip contains, from bottom to top, a die pad, the semiconductor chip, a wafer coating, multiple lead conductors and encapsulating material. Since the conductors are placed on top of the semiconductor chip, the positions of the bonding terminals of the chip can be freely designed, and the heat generated by the chip can be dissipated through the conductors more effectively. In addition, because of the adoption of the die pad, the mechanical strength of the packaged chip is improved, while the die pad also helps dissipate the heat generated by the chip.
A packaging mechanism for a semiconductor chip comprising: a die pad formed of metal sheet for supporting one of different types of semiconductor chips, the die pad being fixed by means of selvages at both sides of said die pad to form a die pad frame, said die pad being connected through positioning protrusions to said selvages, said positioning protrusions being higher than the plane of said die pad and said selvages by about the thickness of a semiconductor chip attached to said die pad; a semiconductor chip having a major surface with bonding terminals thereon disposed within an encapsulating material; a plurality of self supporting discrete and continuous lead conductors formed of metal sheet extending over said major surface of said semiconductor chip at spaced locations from said bonding terminals and extending from said semiconductor chip and cantilevered out of the encapsulating material; a wafer coating on the major surface of said semiconductor chip for protecting said semiconductor chip from electrical contact to said lead conductors; discrete electrical conducting wires bonded to said lead conductors and said bonding terminals and electrically connecting said lead conductors to said bonding terminals; and the encapsulating material being disposed over and enclosing said bonding terminals, said conducting bond wires, and a portion of said lead conductors, the remainder of said lead conductors being cantilevered out of said encapsulating material.
Claim 2
Dependent Claim
226 words
A packaging mechanism for a semiconductor chip comprising: a die pad formed of metal sheet for supporting one of different types of semiconductor chips, the die pad being fixed by means of selvages at both sides of said die pad to form a die pad frame, said die pad being connected through positioning protrusions to said selvages, said positioning protrusions being higher than the plane of said die pad and said selvages by about the thickness of a semiconductor chip attached to said die pad; a semiconductor chip having a major surface with bonding terminals thereon disposed within an encapsulating material; a plurality of self supporting discrete and continuous lead conductors formed of metal sheet extending over said major surface of said semiconductor chip at spaced locations from said bonding terminals and extending from said semiconductor chip and cantilevered out of the encapsulating material; a wafer coating on the major surface of said semiconductor chip for protecting said semiconductor chip from electrical contact to said lead conductors; discrete electrical conducting wires bonded to said lead conductors and said bonding terminals and electrically connecting said lead conductors to said bonding terminals; and the encapsulating material being disposed over and enclosing said bonding terminals, said conducting bond wires, and a portion of said lead conductors, the remainder of said lead conductors being cantilevered out of said encapsulating material.