The present invention relates to integrated circuit packaging technology, and more particularly, to lead frames, integrated circuit packages, and methods of manufacturing such lead frames and packages.
A conventional lead frame may include a die attachment pad for accommodating a semiconductor die, as well as a number of leads connected to the semiconductor die. Such a conventional lead frame and semiconductor die may be packaged by being encapsulated within a plastic or resinous material. Various shapes and sizes of such packages exist. For example, U.S. Pat. No. 6,229,200 to Mclellan, entitled “Saw-Singulated Leadless Plastic Chip Carrier,” discloses a chip carrier having an encapsulation encapsulating a semiconductor die. In certain standard and conventional lead frames, the leads connected to the semiconductor die may be spaced somewhat far from the semiconductor die's bonding pads when the die is of a relatively small size compared to the lead frame. Therefore, in connection with certain packages, it may be advantageous to have a lead frame which includes a portion of a lead for attachment to the semiconductor die, and another portion of the lead for connection to an external device.
In one aspect, the invention features an integrated circuit package including a lead frame with a lead having an inner pad and an outer pad connected by a connection member, wherein a region of the inner pad and a region of the outer pad are separated by a channel extending through a width of the lead, a semiconductor die electrically coupled with the inner pad of the lead, and an encapsulant material encapsulating at least a portion of the lead frame, wherein a portion of the outer pad is exposed.
In another aspect, the invention features an integrated circuit package including a lead frame having a die attachment pad and a plurality of inwardly projecting leads, each of the leads having an inner pad and an outer pad, wherein a region of the inner pad and a region of the outer pad is separated by a channel extending through a width of the lead and connected by a connection member integral with the inner pad and the outer pad, the connection member having a thickness that is approximately half a thickness of the lead, a semiconductor die electrically coupled with the inner pad of the lead, and an encapsulant material encapsulating at least a portion of the lead frame, wherein a portion of the outer pad is exposed.
In yet another aspect, the invention features a method including providing a matrix of lead frames, each of the lead frames having a lead, forming a channel extending through a width of the lead to create an inner pad, an outer pad and a connection member in the lead, electrically coupling a semiconductor die with the inner pad, and encapsulating at least a portion of the lead frame such that at least a portion of the outer pad is exposed.
In a further aspect, the invention features a method including providing a lead frame having a lead, forming a channel extending through a width of the lead to create an inner pad, an outer pad and a connection member in the lead, electrically coupling a semiconductor die with the inner pad, and encapsulating at least a portion of the lead frame such that at least a portion of the outer pad is exposed.
The foregoing features, methods and other aspects of the invention are explained in the following description taken in connection with the accompanying drawings, wherein:
a-10j show simplified cross-sectional views of certain steps of one type of process for making an integrated circuit package.
It is to be understood that the drawings are exemplary, and are not to be deemed limiting to the full scope of the appended claims.
Various embodiments of devices according to the present invention will now be described with reference to the drawings.
In one embodiment, the lead frame 100 may have inner rows 105 of inner lead pads 102 arranged in a generally annular configuration, and outer rows 107 of outer lead pads 106 arranged in a generally annular configuration. The pitch between adjacent inner lead pads 102 and adjacent out lead pads 106 of a lead frame 100 of one embodiment may be different. As shown in the embodiment depicted in
The lead frame 100 may also include a die attachment pad 108 onto which a semiconductor die 110 may be attached. In such an embodiment, a soft solder may be used to attach the semiconductor die 110 to the die attachment pad 108, which may provide improved thermal performance.
Certain example dimensions are also depicted in FIG. 1. As shown in
The lead frame 100 of the integrated circuit package 10 of one embodiment may be made of an electrically conductive material such as, e.g., copper. However, the lead frame 100 may be made of other metals, electrically conductive materials, or electrically conductive compounds in accordance with other embodiments of the present invention. The lead frame 100 may provide, at least in part, interconnections between the power, input and/or output terminals of the semiconductor die 110 and any external terminals that may be provided on the integrated circuit package 10.
In one embodiment, portions of the upper and lower surfaces of a lead frame 100 may be plated 113 with solder or pure tin (Sn). This solder or pure tin plating 113 may provide an interface surface for mechanical, electrical or both types of connection of the integrated circuit package 10 to an external device (not shown). Alternatively, the lead frame 100 may be pre-plated with palladium to avoid silver migration.
As is further shown in
According to certain embodiments, shown in
As shown in
Methods of manufacturing embodiments of integrated circuit packages will now be described with reference to the drawings, in particular,
A lead frame 100 may be formed into the configuration shown in the figures by a number of different processes including a chemical process (e.g., etching), a mechanical process (e.g., metal stamping), or a combination of these and/or other processes. As represented in
As depicted in
In one example manufacturing process, as shown in
After the adhesive is cured, if required, the semiconductor die 110 may be wire-bonded to the inner lead pads 102 of the leads 101 using automated bonding equipment including a moving capillary device 1001 (see
Following attachment of the semiconductor die 110 to the lead frame 100, the pre-assembly may be encapsulated. As shown in
As shown in
In one example method embodiment of the present invention, after the encapsulation and ball attachment assembly steps, the integrated circuit packages 10, 20 may be singulated into individual units using a saw singulation or punching technique (shown in
Although illustrative embodiments and example methods have been shown and described herein in detail, it is to be understood that there may be numerous variations, embodiments, and examples which may be equivalent to those explicitly shown and described. For example, the scope of the present invention may not necessarily be limited in all cases to execution of the aforementioned steps in the order discussed. Unless otherwise specifically stated, the terms and expressions have been used herein as terms and expressions of description, not of limitation. Accordingly, the invention is not to be limited by the specific illustrated and described embodiments and examples (or terms or expressions used to describe them), but only by the scope of the appended claims.
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