Patent Application
20060037995
During a semiconductor packaging process, an integrated circuit (“IC”) is mounted inside a plastic mold compound (“package”). Various points on the IC are electrically connected to lead frames circumscribing the package using bond wires. In turn, the lead frames circumscribing the package are electrically connected to an application board, such as a printed circuit board (“PCB”). In this way, multiple electrical connections are established between the IC and the PCB. For example,
The IC 100 abuts a heat slug 200 that is used to conduct heat away from the IC 100 and out of the package 104. During a packaging process, the heat slug 200 is coupled to the lead frame 102 using a riveting technique, wherein the heat slug 200 is punched through apertures 202 in the lead frame 102 and flattened on the opposite side of the lead frame 102, as shown in
However, this time-consuming riveting technique requires the use of a riveting machine, which adds to the cost of the manufacturing process. Furthermore, the mechanics of the riveting machine require the riveting process to be performed prior to package assembly. For this reason, during package assembly, the riveted lead frame 102 and heat slug 200 are fixed in place. Thus, the package 104 is limited in size and design flexibility.
The problems noted above are solved in large part by a clamping technique that couples a heat slug to a lead frame without the use of a clamping machine. One exemplary embodiment may be a method for coupling a heat slug to a lead frame, comprising aligning a heat slug and a lead frame, depositing a material between the heat slug and the lead frame, and clamping together the heat slug and the lead frame.
For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:
a shows a top vie of a printed circuit board (“PCB”) abutting a leaded package;
b shows a cross sectional side view of a lead frame coupled to a heat slug using a riveting technique;
a-2d show a cross sectional side view of a lead frame and a heat slug coupled using the clamping technique, in accordance with embodiments of the invention;
a-4d show a cross sectional side view process flow of a lead frame and a heat slug coupled using the clamping technique, in accordance with embodiments of the invention;
a-6c show a cross sectional side view process flow of a lead frame and a heat slug coupled using the clamping technique, in accordance with embodiments of the invention; and
Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
Presented herein is a clamping technique that couples a heat slug to a lead frame without the use of a riveting machine.
The lead frame 102 then is held abutting the heat slug 200 with one or more clamps 250 (block 301). As shown in
a-4d show the lead frame 102 being electrically coupled to the heat slug 200 by way of another embodiment of the clamping technique mentioned above.
a-6c show the lead frame 102 being mechanically and/or electrically coupled to the heat slug 200 by way of yet another embodiment of the clamping technique mentioned above.
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
