Patent Application
20060289986
It is customary to package an integrated circuit (IC) die within a structure (known as an IC package) that includes a package substrate on which the IC die mounted and a cap which is attached to the package substrate to protect the IC die from above. Typically the package substrate has traces formed therein (sometimes several layers of traces) to route signal paths from the die to contacts provided on the bottom surface of the package substrate. The packaged die is then mounted to a circuit board and is connected to traces in the board via the contacts on the bottom of the package substrate.
So-called “system in package” arrangements have been proposed in which two or more IC dies are housed within a single IC package. In these arrangements, interconnections between the IC dies within the package may be made via traces in the substrate package. However, if a considerable number of such interconnections are required, it may be necessary to lay out the traces in the package substrate with an increased number of layers and/or with increased density. This in turn may increase the cost of manufacture of the package substrate.
The IC package 100 also includes an integrated circuit die 114 mounted on the package substrate 102 in the space 110 between the cap 104 and the package substrate 102. The IC die 114 may, for example, be a microprocessor die or another type of IC die which has a large pin count. The IC die 114 may be mounted on the package substrate 102 in accordance with the conventional “flip chip” technique, for example, such that the front side 116 of the IC die 114 faces toward the package substrate 102. (It will be understood that the “front” side 116 of the IC die is the side on which the integrated circuitry is formed.) The back side 118 of the IC die 114 thus faces away from the package substrate 102.
The IC package 100 also includes a section 120 of flex tape. As used herein and in the appended claims, “flex tape” refers to a flexible sheet or strip which contains one or more metal conductive paths therein. The flex tape section 120 is present in the space 110 defined between the package substrate 102 and the cap 104. The flex tape section 120 has an end 122 which is coupled to the back side 118 of the IC die 114. The IC die 114 has one or more through-chip vias (schematically represented at 124) to provide one or more signal paths between the flex tape section 120 and the integrated circuitry on the front side 116 of the IC die 114. One or more conductors in the flex tape section 120 may be solder-connected to one or more conductive paths in the through-chip vias 124 of the IC die 114.
In addition, the IC package 100 includes another IC die 126 mounted in the space 110 defined between the package substrate 102 and the cap 104. The IC die 126 may, for example, be a memory device (e.g., a flash memory) or another type of IC die which has a relatively small pin count. The IC die 126 is supported on the substrate package 102 with an end 128 of the flex tape section 120 sandwiched between the IC die 126 and the package substrate 102. Contacts (not separately shown) on the front side 130 of the IC die 126 are conductively coupled (e.g., by solder) to conductors in the flex tape section 120 such that the flex tape section 120 provides one or more signal paths between the IC die 114 and the IC die 126.
Because one or more signal paths between the dies 114, 126 are provided by the flex tape section 120, the number of signal paths to be provided between the dies 114, 126 by the traces 112 in the package substrate 102 may be reduced or eliminated. Consequently, the number of traces in the package substrate 102 may be reduced, so that a package substrate having fewer layers of traces and/or less dense traces may be employed. Thus the cost of manufacture of the package substrate may be reduced.
Also, the flex tape section, being housed within the structure of the IC package, may be protected from potential damage that may occur in conventional usage of flex tape to provide connections from one IC package to another IC package.
The IC package 100 may also include a thermal interface material (TIM), which is not shown, to thermally couple the back side 118 of the IC die 114 to the cap (IHS) 104. The TIM may cover substantially all of the back side 118 of the IC die 114, omitting only the relatively small portion of the back side 118 to which the end 122 of the flex tape section 120 is coupled.
Also, the IC package 100a includes a third IC die 136 mounted in the space 110 defined between the package substrate 102 and the cap 104. The IC die 136 may, for example, be another type of IC die which has a relatively small pin count. The IC die 136 is supported on the substrate package 102 with an end 138 of the flex tape section 132 sandwiched between the IC die 136 and the package substrate 102. Contacts (not separately shown) on the front side 140 of the IC die 136 are conductively coupled to conductors in the flex tape section 132 such that the flex tape section 132 provides one or more signal paths between the IC die 114 and the IC die 136.
In some embodiments, there may be more than three IC dies inside the IC package, and/or there may be more than two sections of flex tape interconnecting the IC dies. Some interconnections between IC dies inside the IC package may be provided by traces in the package substrate 102.
Like the previous embodiments, the IC package 100b includes the package substrate 102 and the cap 104 which define the space 110 therebetween. The IC package 100b also includes IC dies 114, 150, both contained in the space 110 and mounted on the package substrate 102. Both of the IC dies 114, 150 may have relatively high pin counts.
The IC package 100b also includes a section 152 of flex tape contained within the space 110. The flex tape section 152 has one end 154 coupled, as before, to the back side 118 of the IC die 114, and its other end 156 coupled to the back side 158 of the IC die 150. Each IC die 114, 150 has one or more through-chip vias 124 to couple the flex tape section 152 to the respective integrated circuitry on the front sides of the IC dies. Thus the flex tape section 152 provides one or more signal paths between the IC dies 114, 150.
At 602 in
At 608, the other end of the flex tape section if attached to the back side of the microprocessor die, in such a manner as to conductively couple one or more conductors in the flex tape section with the conductors in one or more of the through-chip vias formed through the microprocessor die. Consequently, the conductors in the flex tape section are operatively coupled to the microprocessor circuitry formed on the front side of the microprocessor die.
At 610 a memory IC die is mounted on the package substrate with the first end of the flex tape section sandwiched between the memory device and the package substrate, and so that circuitry on the front side of the memory device (i.e., the side facing toward the package substrate) is conductively coupled to one or more conductors in the flex tape section. As a result, at least some conductive paths between the memory device and the microprocessor are provided by the flex tape section. In some embodiments, all connections to the memory device are by way of the flex tape section.
At 612, a cap (e.g., an IHS) is attached to the package substrate to close the package and to protect the microprocessor, the memory device and the flex tape section during further manufacturing stages, handling, shipment, etc.
The process described in connection with
The processes as described herein and in the appended claims are not meant to imply a fixed order of performing the process stages; rather, the process stages may be performed in any order that is practicable.
The chipset 714 may, for example, be packaged together with the microprocessor die 710 or may alternatively be located outside of the package in which the microprocessor die 710 is housed. Some or all of the other components shown in
The several embodiments described herein are solely for the purpose of illustration. The various features described herein need not all be used together, and any one or more of those features may be incorporated in a single embodiment. Therefore, persons skilled in the art will recognize from this description that other embodiments may be practiced with various modifications and alterations.
