Digital and RF system and method therefor

• US 20040195591A1
• Filed: 11/22/2002
• Published: 10/07/2004
• Est. Priority Date: 11/22/2002
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Christensen, Brian H., Rohde, John, Mistry, Addi B., Patten, David, Kleffner, James H., Gehman, John, Wilde, Daryl
• Granted Patent: US 7,479,407 B2
• Time in Patent Office: Days
• US Class Current: 257/202
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/48471 the other connecting portion not on the bonding area being a ball bond, i.e. wedge-to-ball, reverse stitch
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73215 Layer and wire connectors
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2224/73257 Bump and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 2225/0651 Wire or wire-like electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06527 Special adaptation of electrical connections, e.g. rewiring, engineering changes, pressure contacts, layout
• CPC Class Codes: H01L 2225/06555 Geometry of the stack, e.g. form of the devices, geometry to facilitate stacking
• CPC Class Codes: H01L 2225/06575 Auxiliary carrier between devices, the carrier having no electrical connection structure
• CPC Class Codes: H01L 23/3128 : the substrate having spherical bumps for external connection
• CPC Class Codes: H01L 23/552 : Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

A stacked die system (10) has a first die (16) having a first surface with active circuitry, a second die (18) having a first surface with active circuitry, and a conductive shield (28) interposed between the first surface of the first die and the first surface of the second die. In one embodiment, the distance between the first surfaces of the first and second die is less than one millimeter. The stacked die system may also include a package substrate (12) where the active circuitry of the first and second die are electrically connected to the package substrate. The electrical connections may be formed using wire bonds (56, 58, 60, 62). Alternatively, the first die may be connected to the package substrate in a flip chip configuration. In one embodiment, the active circuitry of the first die generates RF signals where the shield helps protect the RF signals from interference caused by the active circuitry of the second die.

Claims

1. A stacked die system comprising:

a first die having a first surface with active circuitry;

a second die having a first surface with active circuitry; and

a conductive shield interposed between the first surface of the first die and the first surface of the second die, wherein a distance between the first surface of the first die and the first surface of the second die is less than one millimeter.

2. The stacked die system of claim 1, wherein the conductive shield is substantially parallel to the first surfaces of the first and second die.

3. The stacked die system of claim 1, further comprising a package substrate electrically coupled to the active circuitry of the first die and the active circuitry of the second die.

4. The stacked die system of claim 3, wherein the first die is located between the package substrate and the second die.

5. The stacked die system of claim 4, wherein the active circuitry of the first die generates RF signals.

6. The stacked die system of claim 1, further comprising a spacer interposed between the first die and the conductive shield.

7. The stacked die system of claim 6, further comprising:

a first die attach layer between the first die and the spacer; and

a second die attach layer between the conductive shield and the second die.

8. The stacked die system of claim 1, wherein the first die has a second surface opposite the first surface, and wherein a distance between the first surface and the conductive shield is less than a distance between the second surface and the conductive shield.

9. The stacked die system of claim 1, wherein the first die has a second surface, opposite the first surface, and wherein a distance between the first surface and the conductive shield is greater than a distance between the second surface and the conductive shield.

10. The stacked die system of claim 1, wherein the active circuitry of one of first and second die generates RF signals.

11. The stacked die system of claim 1, wherein the first die has an edge surface substantially perpendicular to the first surface of the first die, and wherein the conductive shield extends over the first surface of the first die and substantially surrounds the edge surface of the first die.

12. A stacked die system comprising:

a package substrate;

a first die overlying the package substrate and having a first surface with active circuitry;

a second die overlying the first die and having a first surface with active circuitry, wherein;

the active circuitry of at least one of the first and second die generates RF signals, and

the active circuitry of the first die and the active circuitry of the second die are electrically connected to the package substrate; and

a conductive shield between the first surface of the first die and the first surface of the second die.

13. The stacked die system of claim 12, further comprising a spacer between the conductive shield and the first die.

14. The stacked die system of claim 13, wherein the spacer is adhered to the first die.

15. The stacked die system of claim 14, wherein the second die is adhered to the conductive shield.

16. The stacked die system of claim 12, wherein the first die has a second surface opposite the first surface, and wherein the package substrate is closer to the second surface of the first die than to the first surface of the first die.

17. The stacked die system of claim 12, wherein the first die has a second surface opposite the first surface, and wherein the first surface of the first die is closer to the second surface of the second die than to the first surface of the second die.

18. The stacked die system of claim 12, wherein the first die has a periphery surface substantially perpendicular to the first surface of the first die, and wherein the conductive shield extends over the first surface of the first die and substantially surrounds the periphery surface of the first die.

19. The stacked die system of claim 18, further comprising a plurality of electrical connections from the first surface of the first die to the package substrate, wherein the conductive shield substantially surrounds the periphery surface of the first die and the plurality of electrical connections.

20. The stacked die system of claim 19, wherein the conductive shield is electrically connected to the package substrate.

21. The stacked die system of claim 12, wherein the conductive shield is electrically connected to the package substrate.

22. A stacked die system comprising:

a package substrate having a first surface and a second surface opposite the first surface;

a first die overlying the package substrate and having a first surface and a second surface opposite the first surface, wherein the package substrate is closer to the second surface of the first die than to the first surface of the first die;

a spacer overlying the first die;

a conductive shield overlying the spacer;

a second die overlying the conductive shield, the second die having a first surface and a second surface opposite the first surface, wherein the conductive shield is closer to the second surface of the second die than to the first surface of the second die;

a first plurality of electrical connections from the first surface of the first die to the first surface of the package substrate; and

a second plurality of electrical connections from the first surface of the second die to the first surface of the package substrate.

23. The stacked die system of claim 22, wherein the first and second plurality of electrical connections comprise wire bond connections.

24. The stacked die system of claim 23, wherein the first surface of the first die has active circuitry and the first surface of the second die has active circuitry.

25. The stacked die system of claim 24, wherein the active circuitry of at least one of the first and second die generates RF signals.

26. The stacked die system of claim 25, further comprising an electrical connection from the conductive shield to the package substrate.

27. The stacked die system of claim 22, wherein the second surface of the first die is adhered to the first surface of the package substrate, the spacer is adhered to the first surface of the first die, and the second surface of the second die is adhered to the conductive shield.

28. The stacked die system of claim 22, wherein the conductive shield extends over the plurality of electrical connections to the package substrate, wherein the conductive shield substantially surrounds the plurality of electrical connections.

29. The stacked die system of claim 22, further comprising a plurality of solder balls on the second surface of the package substrate.

30. A method for forming a stacked die system, comprising:

providing a package substrate;

placing a first die over the package substrate, the first die having a first surface with active circuitry;

forming a conductive shield over the first die;

placing a second die over the conductive shield, the second die having a first surface with active circuitry, wherein the conductive shield is between the first surface of the first die and the first surface of the second die;

forming electrical connections between the active circuitry of the first die and the package substrate; and

forming electrical connections between the active circuitry of the second die and the package substrate.

31. The method of claim 30, wherein the active circuitry in one of the first or second die generates RF signals.

32. The method of claim 30, wherein forming the conductive shield over the first die comprises forming the conductive shield over the first die to the package substrate, the conductive field substantially surrounding the electrical connections between the active circuitry of the first die and the package substrate.

33. The method of claim 30, wherein the first die has a second surface opposite the first surface, and wherein placing the first die over the package substrate comprises adhering the second surface to the package substrate.

34. The method of claim 30, further comprising forming a spacer over the first die, wherein the conductive shield is formed over the spacer.

35. A stacked die system comprising:

a package substrate;

a first semiconductor die having a perimeter and disposed over the package substrate;

a second semiconductor die over the first semiconductor die; and

a support mechanism having

a first portion attached to the second die in an area between the first die and the second die; and

a second portion outside the perimeter of the first die and attached to the semiconductor substrate.

36. The stacked die system of claim 35, wherein the support mechanism is non-conductive.

37. The stacked die system of claim 35, wherein the second semiconductor die has a perimeter and the first portion is attached to the second semiconductor die within 100 microns of the perimeter of the second die.

38. The stacked die system of claim 37, wherein the first portion is attached to the second semiconductor die at the perimeter of the second die.

39. The stacked die system of claim 38, wherein the first portion extends beyond the perimeter of the second semiconductor die.

40. The stacked die system of claim 35, wherein

the support mechanism is conductive;

the first semiconductor die has an active surface;

the second semiconductor die has an active surface, and

a distance between the active surfaces of the first and second semiconductor die is not greater than one millimeter.

41. The stacked die system of claim 40, wherein the first semiconductor die has a back surface that is closer to the second semiconductor die than is the active surface of the first semiconductor die.

42. The stacked die system of claim 35, wherein the first portion is a substantially flat conductive layer and the second portion is a plurality of solder balls attached between the package substrate and the substantially flat conductive layer.

43. The stacked die system of claim 35, wherein the support mechanism comprises a perforated cage.

44. The stacked die system of claim 43, wherein the perforated cage is non-conductive.

45. The stacked die system of claim 43, wherein the perforated cage is conductive.

46. The stacked die system of claim 35, wherein the second portion is for providing mechanical support to the second semiconductor die during a wire bond operation on the second semiconductor die.