Abstract: A method for fabricating a semiconductor package having a 2-layer substrate, which includes an array of solder balls, is disclosed. The method includes patterning signal traces on a top layer of the substrate and identifying groups of signal traces to isolate. According to the present invention, a grounded isolation trace is then patterned adjacent to one of the groups of traces to isolate the signal traces, thereby providing noise shielding. In a preferred embodiment, the grounded isolation trace is provided with multiple vias, rather than only one. In a further aspect of the present invention a row of solder balls is connected together and to ground to create a bottom-layer isolating ground trace to further reduce noise. The bottom-layer isolating ground trace may be connected to the top-layer isolating ground trace using a via.

Abstract: A two layer PBGA which includes a metal ground plane at its bottom layer. The ground plane is preferably a metal plane which is connected to ground through a metal connection to a ball pad at the center of the package and a ball pad proximate the edge of the package. The ground plane is voided around the signal and power balls, via and “dog bones”. The PBGA is configured such that the ground plane serves effectively the same function as the second layer ground plane in a conventional four layer PBGA. The PBGA provides a cheaper alternative to the generally more expensive four layer PBGA, and provides better cross talk performance (especially for high frequency signaling) as well as better thermal performance as a result of having more metal at the bottom layer of the package.

Abstract: A method for fabricating a semiconductor package having a 2-layer substrate, which includes an array of solder balls, is disclosed. The method includes patterning signal traces on a top layer of the substrate and identifying groups of signal traces to isolate. According to the present invention, a grounded isolation trace is then patterned adjacent to one of the groups of traces to isolate the signal traces, thereby providing noise shielding. In a preferred embodiment, the grounded isolation trace is provided with multiple vias, rather than only one. In a further aspect of the present invention a row of solder balls is connected together and to ground to create a bottom-layer isolating ground trace to further reduce noise. The bottom-layer isolating ground trace may be connected to the top-layer isolating ground trace using a via.

Abstract: A method for fabricating a semiconductor package having a 2-layer substrate, which includes an array of solder balls, is disclosed. The method includes patterning signal traces on a top layer of the substrate and identifying groups of signal traces to isolate. According to the present invention, a grounded isolation trace is then patterned adjacent to one of the groups of traces to isolate the signal traces, thereby providing noise shielding. In a preferred embodiment, the grounded isolation trace is provided with multiple vias, rather than only one. In a further aspect of the present invention a row of solder balls is connected together and to ground to create a bottom-layer isolating ground trace to further reduce noise. The bottom-layer isolating ground trace may be connected to the top-layer isolating ground trace using a via.

Abstract: A mold for use in encapsulating an integrated circuit, wherein an encapsulant is injected into the mold during packaging of the integrated circuit. The improvement to the mold is a shaped member having an abutting surface for contacting a surface of the integrated circuit and thereby substantially preventing encapsulant from adhering to the surface of the integrated circuit, whereby the surface of the integrated circuit is left exposed. Because the surface of the integrated circuit is left exposed, the encapsulant used to encapsulate the integrated circuit does not form a thermal barrier between the integrated circuit and the exterior of the package. Thus, the packaged integrated circuit is able to more efficiently conduct heat away from the integrated circuit.

Abstract: A method and apparatus for providing a ball grid array assembly formed from interlocking ball grid array packages is disclosed. Each of the ball grid array packages has interlocking edge features for mechanical connection, whereby joining the plurality of ball grid array packages via the interlocking edge features forms the interlocking ball grid array assembly. The interlocking ball grid array assembly may then be mounted on a PC board as a single unit.