Stacked microfeature devices and associated methods Number:7,071,421 from the United States Patent and Trademark Office (PTO) owispatent

Title: Stacked microfeature devices and associated methods

Abstract: Stacked microfeature devices and associated methods of manufacture are disclosed. A package in accordance with one embodiment includes first and second microfeature devices having corresponding first and second bond pad surfaces that face toward each other. First bond pads can be positioned at least proximate to the first bond pad surface and second bond pads can be positioned at least proximate to the second bond pad surface. A package connection site can provide electrical communication between the first microfeature device and components external to the package. A wirebond can be coupled between at least one of the first bond pads and the package connection site, and an electrically conductive link can be coupled between the first microfeature device and at least one of the second bond pads of the second microfeature device. Accordingly, the first microfeature device can form a portion of an electrical link to the second microfeature device.

Patent Number: 7,071,421 Issued on 07/04/2006 to Heng,   et al.

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Inventors:	Heng; Mung Suan (Singapore, SG); Tan; Kok Chua (Singapore, SG); Leong; Vince Chan Seng (Singapore, SG); Johnson; Mark S. (Boise, ID)
Assignee:	Micron Technology, Inc. (Boise, ID)
Appl. No.:	651912
Filed:	August 29, 2003

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Current U.S. Class:	174/260 ; 257/777; 257/784; 29/840; 29/843; 438/109
Current International Class:	H05K 7/06 (20060101); H01L 23/488 (20060101); H01L 23/49 (20060101)

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References Cited [Referenced By]

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Other References

Search Report and Written Opinion for Singapore Application No. 200305589-4, Australian Patent Office, Apr. 8, 2005. cited by other.

Primary Examiner: Vigushin; John B.
Attorney, Agent or Firm: Perkins Coie LLP

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Claims

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We claim:

1. A microfeature device package, comprising: a first microfeature device having a first bond pad surface with a plurality of first bond pads positioned at least proximate to the first bond pad surface; a second microfeature device having a second bond pad surface with a plurality of second bond pads positioned at least proximate to the second bond pad surface, the second bond pad surface facing toward the first bond pad surface; a package connection site positioned to provide electrical communication between the first microfeature device and devices external to the device package; a wirebond coupled between at least one of the first bond pads and the package connection site; and an electrically conductive link coupled between the first microfeature device and at least one of the second bond pads of the second microfeature device, the electrically conductive link including an intermediate bond pad and a volume of solder disposed between the intermediate bond pad and the at least one second bond pad.

2. The package of claim 1 wherein the wirebond is one of a plurality of wirebonds, and wherein all the wirebonds of the package are connected directly to the first microfeature device.

3. The package of claim 1, further comprising an encapsulant disposed adjacent to the first and second microfeature device packages.

4. The package of claim 1 wherein the intermediate bond pad is carried by the first microfeature device and electrically coupled to the at least one first bond pad, and wherein the electrically conductive link is connected between the intermediate bond pad and the at least one second bond pad of the second microfeature device.

5. The package of claim 1 wherein the intermediate bond pad is carried by the first microfeature device and electrically isolated from the at least one first bond pad, and wherein the electrically conductive link is connected between the intermediate bond pad and the at least one second bond pad of the second microfeature device.

6. The package of claim 1 wherein the first and second microfeature devices have generally similar footprints and wherein an arrangement of the plurality of first bond pads is at least generally similar to an arrangement of the plurality of second bond pads.

7. The package of claim 1 wherein the wirebond includes a first wirebond, and wherein the package connection site includes a first package connection site, and wherein the package further comprises: a second package connection site; and a second wirebond connected between the electrically conductive link and the second package connection site.

8. The package of claim 1 wherein the electrically conductive link includes a volume of gold.

9. A microfeature device package, comprising: a first microfeature device having a first bond pad surface with a plurality of first bond pads positioned at least proximate to the first bond pad surface; a second microfeature device having a second bond pad surface with a plurality of second bond pads positioned at least proximate to the second bond pad surface, the second bond pad surface facing toward the first bond pad surface; a package connection site positioned to provide electrical communication between the first microfeature device and components external to the device package; a wirebond coupled between at least one of the first bond pads and the package connection site; and an electrically conductive link coupled between the at least one first bond pad of the first microfeature device and at least one second bond pad of the second microfeature device wherein the electrically conductive link includes an intermediate bond pad electrically coupled to the at least one first bond pad, and a volume of solder disposed between the intermediate bond pad and the at least one second bond pad.

10. The package of claim 9 wherein the electrically conductive link includes a volume of gold.

11. The package of claim 9 wherein the first and second microfeature devices have generally similar footprints and wherein an arrangement of the plurality of first bond pads is at least generally similar to an arrangement of the plurality of second bond pads.

12. The package of claim 9 wherein the first and second microfeature devices are generally identical, and wherein the at least one first bond pad is electrically coupled to a first intermediate bond pad of the first microfeature device, and wherein the at least one second bond pad is electrically coupled to a second intermediate bond pad of the second microfeature device, and wherein the electrically conductive link includes a volume of solder disposed between the first intermediate bond pad and the at least one second bond pad.

13. The package of claim 9 wherein the package connection site includes a common package connection site electrically coupled to both the first and second microfeature devices, and wherein the package further comprises: a first package connection site electrically coupled to another of the first bond pads; and a second package connection site electrically coupled to another of the second bond pads, with the first and second connection sites electrically decoupled from each other within the package.

14. A microfeature device package, comprising: a first microfeature device having a first bond pad surface with a plurality of first bond pads and a plurality of intermediate bond pads positioned at least proximate to the first bond pad surface; a second microfeature device having a second bond pad surface with a plurality of second bond pads positioned at least proximate to the second bond pad surface, the second bond pad surface facing toward the first bond pad surface; a first package connection site positioned to provide electrical communication between the first microfeature device and components external to the device package; a first wirebond coupled between at least one of the first bond pads and the first package connection site; a second package connection site positioned to provide electrical communication between the second microfeature device and devices external to the device package; a second wirebond coupled between at least one of the intermediate bond pads and the second package connection site; and an electrically conductive link coupled between the at least one intermediate bond pad and at least one of the second bond pads of the second microfeature device, the electrically conductive link including a volume of solder disposed between the at least one intermediate bond pad and the at least one second bond pad.

15. The package of claim 14 wherein the electrically conductive link includes a volume of gold.

16. The package of claim 14 wherein the second microfeature device has a footprint that is larger than a footprint of the first microfeature device package.

17. The package of claim 14 wherein no wirebonds of the package are connected directly to the second microfeature device.

18. The package of claim 14 wherein the at least one intermediate bond pad includes a first intermediate bond pad, and wherein the second microfeature device has a second intermediate bond pad electrically coupled to the at least one second bond pad, further wherein the electrically conductive link is disposed between the first and second intermediate bond pads.

19. A method for forming a microfeature device package, comprising: positioning a first microfeature device at least proximate to a second microfeature device, the first microfeature device having a first bond pad surface with a plurality of first bond pads at least proximate to the first bond pad surface, the second microfeature device having a second bond pad surface with a plurality of second bond pads at least proximate to the second bond pad surface, the first bond pad surface facing toward the second bond pad surface; coupling a wirebond between at least one of the first bond pads and a package connection site, the package connection site being positioned to provide electrical communication between the first microfeature device and components external to the device package; and coupling an electrically conductive link between the first microfeature device and at least one of the second bond pads of the second microfeature device by disposing a volume of solder between the at least one second bond pad and an intermediate bond pad electrically coupled to the at least one first bond pad.

20. The method of claim 19 wherein the wirebond is one of a plurality of wirebonds, and wherein the method further comprises connecting all the wirebonds of the package directly to the first microfeature device.

21. The method of claim 19, further comprising disposing an encapsulant adjacent to the first and second microfeature device packages.

22. The method of claim 19 wherein the intermediate bond pad is carried by the first microfeature device and electrically coupled to the at least one first bond pad, and wherein coupling an electrically conductive link between the first microfeature device and the at least one second bond pad includes coupling the electrically conductive link between the intermediate bond pad and the at least one second bond pad.

23. The method of claim 19 wherein intermediate bond pad is carried by the first microfeature device and electrically isolated from the at least one first bond pad, and wherein coupling an electrically conductive link includes coupling an electrically conductive link between the intermediate bond pad and the at least one second bond pad of the second microfeature device.

24. The method of claim 19 wherein positioning a first microfeature device includes positioning a first microfeature device having a first footprint and a first arrangement of bond pads, with the first footprint being generally similar to a second footprint of the second microfeature device and with the first arrangement being at least generally similar to a second arrangement of the plurality of second bond pads.

25. The method of claim 19 wherein coupling an electrically conductive link includes coupling a wirebond.

26. The method of claim 19 wherein coupling an electrically conductive link includes coupling a volume of solder.

27. A method for forming a microfeature device package, comprising: positioning a first microfeature device at least proximate to a second microfeature device, the first microfeature device having a first bond pad surface with a plurality of first bond pads at least proximate to the first bond pad surface, the second microfeature device having a second bond pad surface with a plurality of second bond pads at least proximate to the second bond pad surface, the first bond pad surface facing toward the second bond pad surface; coupling a wirebond between at least one of the first bond pads and a package connection site, the package connection site being positioned to provide electrical communication between the first microfeature device and devices external to the device package; and coupling an electrically conductive link between the at least one first bond pad of the first microfeature device and at least one second bond pad of the second microfeature device, wherein coupling an electrically conductive link includes disposing a volume of solder between the at least one second bond pad and an intermediate bond pad electrically coupled to the at least one first bond pad.

28. The method of claim 27 wherein coupling an electrically conductive link includes coupling a volume of solder.

29. The method of claim 27 wherein positioning a first microfeature device at least proximate to a second microfeature device includes positioning a first microfeature device having a first footprint generally similar to a second footprint of the second microfeature device and having an arrangement of the plurality of first bond pads at least generally similar to an arrangement of the plurality of second bond pads.

30. The method of claim 27 wherein the first and second microfeature devices are generally identical, and wherein the at least one first bond pad is electrically coupled to a first intermediate bond pad of the first microfeature device, and wherein the at least one second bond pad is electrically coupled to a second intermediate bond pad of the second microfeature device, and wherein coupling an electrically conductive link includes disposing a volume of solder between the first intermediate bond pad and the at least one second bond pad.

31. The method of claim 27 wherein the package connection site includes a common package connection site electrically coupled to both the first and second microfeature devices, and wherein the package further comprises: electrically coupling a first package connection site to another of the first bond pads; and electrically coupling a second package connection site to another of the second bond pads, with the first and second connection sites electrically decoupled from each other within the package.

32. A method for forming a microfeature device package, comprising: positioning a first microfeature device at least proximate to a second microfeature device, the first microfeature device having a first bond pad surface with a plurality of first bond pads at least proximate to the first bond pad surface and a plurality of intermediate bond pads positioned, the second microfeature device having a second bond pad surface with a plurality of second bond pads at least proximate to the second bond pad surface, the first bond pad surface facing toward the second bond pad surface; coupling a first wirebond between at least one of the first bond pads and a first package connection site, the first package connection site being positioned to provide electrical communication between the first microfeature device and devices external to the device package; coupling a second wirebond between at least one of the intermediate bond pads and a second package connection site, the second package connection site being positioned to provide electrical communication between the second microfeature device and devices external to the device package; and coupling an electrically conductive link between the at least one intermediate bond pad and at least one of the second bond pads of the second microfeature device, wherein coupling an electrically conductive link includes disposing a volume of solder between the at least one second bond pad and the at least one intermediate bond pad electrically coupled to the at least one first bond pad.

33. The method of claim 32 wherein coupling an electrically conductive link includes coupling a volume of gold.

34. The method of claim 32 wherein positioning a first microfeature device proximate to a second microfeature device includes positioning a first microfeature device having a footprint that is smaller than a footprint of the second microfeature device.

35. The method of claim 33, further comprising coupling no wirebonds of the package directly to the second microfeature device.

36. The method of claim 33 wherein the at least one intermediate bond pad includes a first intermediate bond pad, and wherein the second microfeature device has a second intermediate bond pad electrically coupled to the at least one second bond pad, further wherein coupling an electrically conductive link includes disposing the electrically conductive link between the first and second intermediate bond pads.

37. A microfeature device package, comprising: a first microfeature device having a first bond pad surface with a plurality of first bond pads positioned at least proximate to the first bond pad surface; a second microfeature device having a second bond pad surface with a plurality of second bond pads positioned at least proximate to the second bond pad surface, the second bond pad surface facing toward the first bond pad surface; a package connection site positioned to provide electrical communication between the first microfeature device and components external to the device package, the package connection site including a common package connection site electrically coupled to both the first and second microfeature devices; a wirebond coupled between at least one of the first bond pads and the package connection site; an electrically conductive link coupled between the at least one first bond pad of the first microfeature device and at least one second bond pad of the second microfeature device; a first package connection site electrically coupled to another of the first bond pads; and a second package connection site electrically coupled to another of the second bond pads, with the first and second connection sites electrically decoupled from each other within the package.

38. A microfeature device package, comprising: a first microfeature device having a first bond pad surface with a plurality of first bond pads and a first intermediate bond pad positioned at least proximate to the first bond pad surface; a second microfeature device having a second bond pad surface with a plurality of second bond pads and a second intermediate bond pad electrically coupled to at least one second bond pad positioned at least proximate to the second bond pad surface, the second bond pad surface facing toward the first bond pad surface; a first package connection site positioned to provide electrical communication between the first microfeature device and components external to the device package; a first wirebond coupled between at least one of the first bond pads and the first package connection site; a second package connection site positioned to provide electrical communication between the second microfeature device and devices external to the device package; a second wirebond coupled between the first intermediate bond pad and the second package connection site; and an electrically conductive link disposed between the first and second intermediate bond pads.

39. A method for forming a microfeature device package, comprising: positioning a first microfeature device at least proximate to a second microfeature device, the first microfeature device having a first bond pad surface with a plurality of first bond pads at least proximate to the first bond pad surface, the second microfeature device having a second bond pad surface with a plurality of second bond pads at least proximate to the second bond pad surface, the first bond pad surface facing toward the second bond pad surface; coupling a wirebond between at least one of the first bond pads and a package connection site, the package connection site being positioned to provide electrical communication between the first microfeature device and devices external to the device package and including a common package connection site electrically coupled to both the first and second microfeature devices; coupling an electrically conductive link between the at least one first bond pad of the first microfeature device and at least one second bond pad of the second microfeature device; electrically coupling a first package connection site to another of the first bond pads; and electrically coupling a second package connection site to another of the second bond pads, with the first and second connection sites electrically decoupled from each other within the package.

40. A method for forming a microfeature device package, comprising: positioning a first microfeature device at least proximate to a second microfeature device, the first microfeature device having a first bond pad surface with a plurality of first bond pads and a first intermediate bond pad at least proximate to the first bond pad surface, the second microfeature device having a second bond pad surface with a plurality of second bond pads and a second intermediate bond pad electrically coupled to at least one second bond pad and at least proximate to the second bond pad surface, the first bond pad surface facing toward the second bond pad surface; coupling a first wirebond between at least one of the first bond pads and a first package connection site, the first package connection site being positioned to provide electrical communication between the first microfeature device and devices external to the device package; coupling a second wirebond between the first intermediate bond pad and a second package connection site, the second package connection site being positioned to provide electrical communication between the second microfeature device and devices external to the device package; and disposing an electrically conductive link between the first and second intermediate bond pads.

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Description

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TECHNICAL FIELD

The present invention is directed generally to stacked microfeature devices and methods for manufacturing such packages.

BACKGROUND

One method for increasing the density of microelectronic circuits for electronic devices (such as computers, portable phones, etc.) is to stack two or more microelectronic dies on top of each other. Accordingly, this arrangement can provide additional circuits within the same footprint normally occupied by a single die. FIG. 1 is a partially schematic, cross-sectional elevational view of an existing stacked die package 10. The package 10 includes a substrate 40 that carries a first die 20 and a stacked second die 30. The first die 20 is attached to the substrate 40 with a paste layer 14. A spacer 12 is attached to the first die 20 with a first tape layer 13a. The second die 30 is attached to the spacer 12 with a second tape layer 13b.

The first die 20 includes first die bond pads 21 that are coupled to corresponding first substrate bond pads 41a with first wirebonds 50a. The first substrate bond pads 41a are coupled to external substrate bond pads 41c with vias. The external substrate bond pads 41c each have a substrate solder ball 42 to provide communication between the first die 20 and devices located external to the package 10. Similarly, the second die 30 includes second die bond pads 31 coupled to corresponding second substrate bond pads 41b with second wirebonds 50b. The second substrate bond pads 41b are coupled to additional external substrate bond pads 41c to provide communication between the second die 30 and devices external to the package. Once the first and second wirebonds 50a, 50b are connected, the substrate 40, the first die 20, and the second die 30 can be at least partially enclosed with an encapsulant 12 to protect these components.

One feature of an arrangement shown in FIG. 1 is that the overall thickness of the package 10 can be significantly greater than the combined thicknesses of the substrate 40, the first die 20, and the second die 30. As a result, the package 10 can be difficult to integrate into devices having very tight vertical clearances. Accordingly, the benefits of the stacked die arrangement provided to the standard size devices in which they are incorporated may not be available for very compact devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially schematic, cross-sectional elevation view of a package having stacked microelectronic dies in accordance with the prior art.

FIG. 2 is a partially schematic, cross-sectional elevation view of a package having dies stacked and coupled in accordance with an embodiment of the invention.

FIG. 3 is a partially schematic, partially exploded isometric view of two dies positioned to be stacked in accordance with another embodiment of the invention.

FIG. 4 is a partially schematic, partially exploded view of two dies positioned to be stacked in accordance with yet another embodiment of the invention.

FIG. 5 is a partially schematic, partially exploded view of two dies having off-center bond pads and being positioned to be stacked in accordance with still another embodiment to the invention.

DETAILED DESCRIPTION

A. Introduction

The present invention is directed to stacked microfeature devices and associated methods. The term "microfeature device" is used throughout to include a device formed from a substrate upon which and/or in which submicron circuits or components and/or data storage elements or layers are fabricated. Submicron features in the substrate include, but are not limited to, trenches, vias, lines, and holes. These features typically have a submicron width (e.g., ranging from, for example, 0.1 micron to 0.75 micron) generally transverse to a major surface (e.g., a front side or a back side) of the device. The term microfeature device is also used to include substrates upon which and/or in which micromechanical features are formed. Such features include read/write head features and other micromechanical features having submicron or supermicron dimensions. In many of these embodiments, the substrate is formed from suitable materials, including ceramics, and may support layers and/or other formations of other materials, including but not limited to metals, dielectric materials and photoresists.

A microfeature device package in accordance with one aspect of the invention can include a first microfeature device having a plurality of first bond pads at least proximate to a first bond pad surface, and a second microfeature device having a plurality of second bond pads at least proximate to a second bond pad surface. The second bond pad surface can face toward the first bond pad surface. A package connection site can be positioned to provide electrical communication between the first microfeature device and components external to the device package. A wirebond can be coupled between at least one of the first bond pads and the package connection site, and an electrically conductive link can be coupled between the first microfeature device and at least one of the second bond pads of the second microfeature device.

In a particular aspect of the invention, the wirebond is one of a plurality of wirebonds and all the wirebonds of the package are connected directly to the first microfeature device. In a further particular aspect of the invention, the first microfeature device includes an intermediate bond pad electrically coupled to the at least one first bond pad, and the electrically conductive link is connected between the intermediate bond pad and the at least one second bond pad of the second microfeature device. In yet another aspect of the invention, the first microfeature device includes an intermediate bond pad electrically isolated from the at least one first bond pad, and the electrically conductive link is connected between the intermediate bond pad and the at least one second bond pad of the second microfeature device.

The present invention is also directed towards methods for forming a microfeature device package. In one aspect of the invention, the method includes positioning a first microfeature device at least proximate to a second microfeature device, with the first microfeature device having a first bond pad surface with a plurality of first bond pads at least proximate to the first bond pad surface, and with the second microfeature device having a second bond pad surface with a plurality of second bond pads at least proximate to the second bond pad surface. The first bond pad surface can be positioned to face toward the second bond pad surface. A wire bond can be coupled between at least one of the first bond pads and a package connection site that is positioned to provide electrical communication between the first microfeature device and components external to the device package. An electrically conductive link can be coupled between the first microfeature device and at least one of the second bond pads of the second microfeature device.

In a particular aspect of the invention, the wire bond is one of a plurality of wire bonds and the method further includes connecting all the wire bonds of the package directly to the first microfeature device. In other aspects of the invention, the first microfeature device can include an intermediate bond pad electrically coupled to the at least one first bond pad, and coupling an electrically conductive link between the first microfeature device and the at least one second bond pad can include coupling the electrically conductive link between the intermediate bond pad and the at least one second bond pad. In yet another aspect of the invention, the intermediate bond pad is electrically isolated from the at least one first bond pad.

B. Methods and Apparatuses in Accordance with Embodiments of the Invention

Several specific details of the invention are set forth in the following description and in FIGS. 2 5 to provide a thorough understanding of certain embodiments of the invention. One skilled in the art, however, will understand that the present invention may have additional embodiments, and that other embodiments of the invention may be practiced without several of the specific features explained in the following description.

FIG. 2 is a partially schematic, cross-sectional illustration of a package 110 having a first microfeature device 120 and a second microfeature device 130 stacked in accordance with an embodiment of the invention. In one aspect of this embodiment, all the wirebonds within the package 110 can be attached directly to the first microfeature device 120, with some wirebonds communicating only with the first microfeature device 120, and with others communicating only with the second microfeature device 130, via additional electrical links positioned between the first microfeature device 120 and the second microfeature device 130. In another embodiment, at least some of the wirebonds can be coupled to both the first microfeature device 120 and the second microfeature device 130. In both embodiments, the first microfeature device 120 can provide a platform that supports electrical links coupled to the second microfeature device 130. As described in greater detail below, this arrangement can reduce the overall thickness of the package 110 by eliminating wirebonds connected directly to the second microfeature device 130.

In one aspect of an embodiment shown in FIG. 2, the package 110 includes a support member 140, for example, a printed circuit board. The support member 140 can carry the first and second devices 120, 130 and can provide for electrical communication between these devices, as well as devices or circuits external to the package 110. Accordingly, the support member 140 can have a plurality of package connection sites 143, shown in FIG. 2 as first package connection sites 143a and second package connection sites 143b offset forward of the first package connection sites 143a. Each of the package connection sites 143 can include a package connector 142 to provide for communication with elements external to the package 110. In one embodiment, the package connectors 142 include solder balls and in other embodiments, the package connectors 142 include other electrically conductive structures. In any of these embodiments, the first package connection sites 143a can be coupled to first support member bond pads 141a with a vias that extend through the support member 140. The second package connection sites 143b can be coupled to corresponding second support member bond pads 141b, also with vias that extend through the support member 140. The first support member bond pads 141a and the second support member bond pads 141b are connected to the first microfeature device 120 and the second microfeature device 130, respectively, as described in greater detail below.

In one aspect of an embodiment shown in FIG. 2, the first microfeature device 120 can be attached to the support member 140 with a paste layer 114. In other embodiments, the first microfeature device 120 can be attached to the support member 140 with other arrangements. In any of these embodiments, the first microfeature device 120 can include first device bond pads 121 that are electrically coupled to features located within the first microfeature device 120. The first device bond pads 121 can be connected to the first support member bond pads 141a with first wirebonds 150a. In a particular aspect of this embodiment, each of the first wirebonds 150a can be attached to a stud bump (e.g., a gold stud bump) or other feature located at the corresponding first device bond pad 121 to improve the physical and/or electrical characteristics of the connection between the wirebond 150a and the first device bond pad 121. In other embodiments, the first wirebond 150a can be attached directly to the first device bond pad 121. In still a further aspect of this embodiment, the first wirebond 150a can be attached first to the support member 140 and then to the first microfeature device 120, for example, to reduce the extent of the wirebond loop.

The first microfeature device 120 can also carry intermediate bond pads 122. In one aspect of this embodiment, some or all of the intermediate bond pads 122 are not electrically connected to features within the first microfeature device 120, but instead, provide an intermediate point in an electrical communication link between the second microfeature device 130 and the support member 140. In another embodiment, at least some of the intermediate bond pads 122 are electrically connected to corresponding first device bond pads 122 (e.g., via a redistribution layer) or directly to features within the first microfeature device 120. In another embodiment, the intermediate bond pads 122 can be connected to the second substrate bond pads 141b with second wirebonds 150b. As described in greater detail below, the second microfeature device 130 can also be electrically coupled to the intermediate bond pads 122 to complete the communication link between the second package connection sites 143b located at the support member 140, and the features within the second microfeature device 130.

The second microfeature device 130 can include second bond pads 131 that are electrically connected to features within the second microfeature device 130. In one aspect of an embodiment shown in FIG. 2, the second bond pads 131 may not be aligned directly above the intermediate bond pads 122 located on the first microfeature device 120. Accordingly, the second microfeature device 130 can include auxiliary bond pads 132 which are aligned with the intermediate bond pads 122. The auxiliary bond pads 132 can be connected to the second bond pads 131 with couplers 134. In one embodiment, the couplers 134 are part of a redistribution layer, and in other embodiments, the couplers 134 have other arrangements. In one aspect of an embodiment shown in FIG. 2, the coupling between the auxiliary bond pads 132 and the second bond pads 131 can be at the surface of the second microfeature device 130. In other embodiments, the connection between the bond pads 131, 132 can be located within the interior of the second microfeature device 130. In any of these embodiments, the auxiliary bond pad 132 can be connected to an electrically conductive member 133 that is aligned with a corresponding one of the intermediate bond pads 122 on the first microfeature device 120 below. In one embodiment, the electrically conductive member 133 includes a stud bump, (e.g., a gold stud bump, a copper stud bump or a solder bump) and in other embodiments, the electrically conductive member 133 includes other structures. In any of these embodiments, the electrically conductive member 133 can be physically and electrically bonded to the intermediate bond pad 122 and/or to the portion of the second wirebond 150b attached to the intermediate bond pad 122.

In a particular aspect of an embodiment shown in FIG. 2, the package 110 is subjected to ultrasonic energy and/or an elevated temperature to secure the connection between the auxiliary bond pad 132 and the intermediate bond pad 122. In other embodiments, other techniques are used to secure this connection. In any of these embodiments, the connection between the auxiliary bond pad 132 and the intermediate bond pad 122 can both physically secure the second microfeature device 130 to the first microfeature device 120, and can provide electrical communication between the second device bond pad 131 and the second package connection site 143b. Once this connection is complete, an optional encapsulant 111 can be disposed over the support member 140, the first microfeature device 120 and the second microfeature device 130 to protect these components. In one embodiment, the encapsulant 111 can include a no-sweep encapsulant, available from KNS of Willow Grove, Pa. In other embodiments, the encapsulant 111 can include other products.

One feature of an embodiment of the package 110 described above with reference to FIG. 2 is that the second wirebonds 150b need not extend around the outwardly facing edges 160 of the second microfeature device 130. Instead, the second wirebonds 150b attach to the intermediate bond pads 122 of the first microfeature device 120, with the electrically conductive member 133 providing the link to the second microfeature device 130. One advantage of this feature is that the overall thickness T of the package 110 can be reduced when compared with existing packages because the encapsulant 111 need not extend beyond the second microfeature device 130 by an amount necessary to envelope the second wirebond 150b. Instead, the second wirebond 150b is positioned between the first microfeature device 120 and the second microfeature device 130. Because the resulting package 110 is accordingly thinner than conventional structural die packages, it can more easily be installed in locations that require a low profile device.

Another advantage of the foregoing arrangement is that the encapsulant 111 need not envelop the entire second microfeature device 130. For example, if the second microfeature device 130 includes a first surface 135a and a second oppositely facing surface 135b, the second surface 135b need not be covered with the encapsulant 111. As a result the rate at which heat is transferred from the second microfeature device 130 can be enhanced, due to the exposed second surface 135b.

Another feature of an embodiment of the package 110 described above with reference to FIG. 2 is that the package 110 can have package outer edges 115 that are located more closely to the device outer edges 160 of the second microfeature device 130 than are the outer edges of existing packages. In particular, because the second wirebonds 150b need not extend around the device outer edges 160, the package outer edges 115 can be flush with the device outer edges 160, or can extend only a short distance outwardly from the device outer edges 160. Accordingly, the overall width W of the package 110 can also be reduced when compared with existing packages and the package 110 can accordingly be more easily installed in locations having tight lateral space constraints.

Still another feature of an embodiment of the package 110 described above with reference to FIG. 2 is that all the wirebonds of the package 110 can be connected to the first microfeature device 120 and none connected to the second