1. Field of the Invention
The present invention relates generally to the field of chip packaging and, more particularly, to a high-pin-count quad flat non-leaded (QFN) semiconductor package having extended terminal leads and fabrication method thereof.
2. Description of the Prior Art
The handheld consumer market is aggressive in the miniaturization of electronic products. Driven primarily by the cellular phone and digital assistant markets, manufacturers of these devices are challenged by ever shrinking formats and the demand for more PC-like functionality. Additional functionality can only be achieved with higher performing logic IC's accompanied by increased memory capability. This challenge, combined together in a smaller PC board format, asserts pressure on surface mount component manufactures to design their products to command the smallest area possible.
Many of the components used extensively in today's handheld market are beginning to migrate from traditional leaded frame designs to non-leaded formats. The primary driver for handheld manufacturers is the saved PC board space created by these components' smaller mounting areas. In addition, most components also have reductions in weight and height, as well as an improved electrical performance. As critical chip scale packages are converted to non-leaded designs, the additional space saved can be allocated to new components for added device functionality. Since non-leaded designs can use many existing leadframe processes, costs to convert a production line can be minimized.
Similar to leaded components, nonleaded designs use wire bond as the primary interconnection between the IC and the frame. However, due to the unique land site geometry and form factor density, traditional wire bond processes may not produce high yielding production. For these designs, additional wire bond capabilities and alternate processes are needed to produce acceptable production yields.
U.S. Pat. No. 6,238,952 discloses a low-pin-count chip package including a die pad for receiving a semiconductor chip and a plurality of connection pads electrically coupled to the semiconductor chip wherein the die pad and the connection pads have a concave profile. A package body is formed over the semiconductor chip, the die pad and the connection pads in a manner that a potion of the die pad and a portion of each connection pad extend outward from the bottom of the package body.
U.S. Pat. No. 6,261,864 discloses a chip package. The semiconductor chip, the die pad, and the connection pads are encapsulated in a package body such that the lower surfaces of the die pad and the connection pads are exposed through the package body. The die pad and the connection pads are formed by etching such that they have a concave profile and a thickness far larger than that of conventional die pad and connection pads formed by plating.
U.S. Pat. No. 6,306,685 discloses a method of molding a bump chip carrier. Dry films are applied to the top and bottom surface of a copper base plate having a suitable thickness. A circuit pattern is formed on each one of the dry films. Metals are plated onto each of the circuit patterns to form connection pads and an exothermic passage. A die is mounted on the copper base plate. The surfaces of the copper base plate on which the die is mounted are molded to form a molding layer.
U.S. Pat. No. 6,342,730 discloses a package structure including a die pad for receiving a semiconductor chip and a plurality of connection pads electrically coupled to the semiconductor chip. The semiconductor chip, the die pad, and the connection pads are encapsulated in a package body such that the lower surfaces of the die pad and the connection pads are exposed through the package body. The die pad and the connection pads have a substantially concave profile.
U.S. Pat. No. 6,495,909 discloses a chip package. The semiconductor chip, the die pad, and the connection pads are encapsulated by a package body in a manner that the lower surfaces of the die pad and the connection pads are exposed through the package body. The die pad and the connection pads have a T-shaped profile thereby prolonging the time for moisture diffusion into the package.
U.S. Pat. No. 6,621,140 discloses a semiconductor package with inductive segments integrally formed in the leadframe. The inductive segments may be connected directly to a lead of the leadframe, or indirectly to a lead or a bond pad on a semiconductor die via wirebonds to form an inductor.