Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Configuration or pattern of bonds
Reexamination Certificate
2002-12-24
2004-09-14
Zarneke, David A. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Configuration or pattern of bonds
C257S687000
Reexamination Certificate
active
06791198
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to microelectronic packaging and, more particularly, to molding an integrated circuit device.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art which may be related to various aspects of the present invention which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Microprocessor-controlled circuits are used in a wide variety of applications. Such applications include personal computers, control systems, telephone networks, and a host of consumer products. As is well known, microprocessors are essentially generic devices that perform specific functions under the control of a software program. This program is stored in a memory device coupled to the microprocessor.
Devices in these types of circuits are typically formed on a semiconductor die and placed together in what is known in the art as a package. Many electrical circuits are packaged for surface mounting. Fine-Pitch Surface Mount Technology (FPT), Pin Grid Array (PGA) technology, and Ball Grid Array (BGA) technology are well developed areas of this type packaging.
The packaging of electrical circuits is a key element in the technological development of any device containing electrical components. A single integrated circuit die is typically encapsulated within a sealed package to be mounted on a printed circuit board (PCB) or another suitable apparatus for incorporation into a system. The integrated circuit die is generally encapsulated within a molding compound to protect the die from external contamination or physical damage. Because the integrated circuit die is encapsulated, the integrated circuit package also provides a system of interconnects for electrically coupling the integrated circuit die to a PCB or other external device.
Three common techniques for mounting an integrated circuit die on a substrate include Chip-on-Board (COB), Board-on-Chip (BOC), and Flip-Chip (F/C) technologies. In a COB package, the integrated circuit die may be attached to the substrate “face-up.” That is to say that the side of integrated circuit die containing the bond pads for wire bonding the integrated circuit die to the substrate is left exposed. This side is often referred to as the upper surface of the die. The backside of the integrated circuit die not containing the bond pads is adhered to the substrate. In this type of package, bond wires are attached from the upper surface of the integrated circuit die and to pads on the upper surface of the substrate to electrically couple the integrated circuit die to the substrate. The substrate contains electrical routing which routes the signals from the upper surface of the substrate to the underside of the substrate.
Alternately, the integrated circuit die may be mounted on the substrate “face-down” to create a BOC. In this instance, the substrate typically contains a slot. Since the integrated circuit die is mounted face down, the bond pads on the upper surface of the die are arranged to correlate with the slot opening in the substrate. Bond wires are attached from the bond pads on the die, through the slot in the substrate, and to the underside of the substrate. The substrate contains electrical routing to distribute electrical signals along the backside of the substrate.
For F/C packages, the integrated circuit die is mounted on the substrate face-down as in the BOC package. For a F/C package, bond wires are not used to electrically couple the integrated circuit die to the substrate. Instead, solder bumps located on the face of the integrated circuit die are aligned with conductive pads on the upper surface of the substrate. The solder bumps may be reflowed to electrically couple the integrated circuit die to the substrate. The substrate contains electrical routing to distribute electrical signals from the die along the backside of the substrate.
Regardless of whether COB, BOC, or F/C mounting techniques are used, the package is generally encapsulated in a molding compound to protect the integrated circuit device and bond wires from external elements such as moisture, dust, or impact. A injection molding system may be used to dispose a molding compound about the package. In this type of system, a molding compound is injected through a runner and onto the package via a gate area.
Typically, a substrate, which usually has several sites, is provided by a substrate manufacturer. Each site is configured to receive an integrated circuit device, such as a memory device. Once the molding process is complete, the substrate is singulated to provide individual integrated circuit (I/C) packages. Due to processing defects, one or more sites on the substrate may be defective. These defective sites are commonly referred to as “X-outs.” When the substrate is populated with I/C devices, the X-outs may be left free of I/Cs. The substrate, whose good sites are populated with I/C devices, is mounted into the injection molding apparatus to encapsulate the packages. During the molding process, molding plates may provide flow paths for the molding compound. One problem associated with the molding process is that the molding compound often “flashes” at the X-outs. That is to say that the molding compound often bleeds out of the packaging area and through the injection molding tooling. The excess molding compound left in the injection molding system may cause defects in the molding of future I/C packages, thus resulting in the failure of parts that would otherwise have been functionally good parts.
The present invention may address one or more of the problems set forth above.
SUMMARY OF THE INVENTION
Certain aspects commensurate in scope with the disclosed embodiments are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
In accordance with one embodiment of the present invention, there is provided a method of molding a substrate comprising the acts of: providing a substrate having a plurality of sites, each site having a gate area and being configured to receive an integrated circuit device; testing the substrate to identify bad sites; disposing a material on the gate area of each bad site; disposing an integrated circuit device on each good site; disposing the substrate onto a molding apparatus; injecting a molding compound through a runner in the molding apparatus; and disposing the molding compound on only the good sites.
In accordance with another embodiment of the present invention, there is provided a method of molding a substrate comprising the acts of: providing a substrate having a plurality of sites, each site having a gate area and being configured to receive an integrated circuit device; testing the substrate to identify bad sites; disposing an integrated circuit device on each good site; disposing the substrate onto a molding apparatus; inserting blocking pins on the gate area of each bad site; injecting a molding compound through a runner in the molding apparatus; and disposing the molding compound on only the good sites.
In accordance with yet another aspect of the present invention, there is provided a method of manufacturing a package comprising the acts of: providing a substrate having a die site and a gate area; and disposing a material on the gate area to block mold compound from entering the die site.
In accordance with still another embodiment of the present invention, there is provided a substrate having at least one die site having a gate area and having a material dispo
Baerlocher Cary
Prindiville Casey L.
Street Bret K.
Yoder Fletcher
Zarneke David A.
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