Method of making a semiconductor chip assembly with a post/base heat spreader and a cavity over the post

• US 8,076,182 B2
• Filed: 02/28/2010
• Issued: 12/13/2011
• Est. Priority Date: 03/25/2008
• Status: Expired due to Fees

• Current Assignee: Bridge Semiconductor Corporation
• Original Assignee: Bridge Semiconductor Corporation
• Inventors: Lin, Charles W. C., Wang, Chia-Chung, Lim, Sangwhoo
• Primary Examiner(s): LINDSAY JR, WALTER LEE
• Application Number:
  US12/714,495
• Publication Number:
  US 20100203679A1
• Time in Patent Office: 653 Days
• Field of Search: 438/118, 438/121, 438/122, 438/26, 438/22, 438/25, 257/98, 257/99, 257/88, 257/59, 257/72, 257/100, 257/E21.499, 257/E25.02, 362/294, 362/310, 362/267, 362/293
• US Class Current: 438/118
• CPC Class Codes: H01L 21/486 Via connections through the substrate with or without pins
• CPC Class Codes: H01L 2224/32188 the layer connector connecting to a bonding area protruding from the surface of the item
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85205 Ultrasonic bonding
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• 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 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/12041 LED
• 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 33/483 Containers
• CPC Class Codes: H01L 33/642 : characterized by the shape
• CPC Class Codes: H05K 1/021 : Components thermally connected to metal substrates or heat-sinks by insert mounting
• CPC Class Codes: H05K 1/182 : associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 2201/09054 : Raised area or protrusion of metal substrate
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 2203/0369 : Etching selective parts of a metal substrate through part of its thickness, e.g. using etch resist
• CPC Class Codes: H05K 3/0061 : onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20

Abstract

A method of making a semiconductor chip assembly includes providing a post and a base, mounting an adhesive on the base including inserting the post into an opening in the adhesive, mounting a substrate on the adhesive including aligning the post with an aperture in the substrate, then flowing the adhesive into and upward in a gap located in the aperture between the post and the substrate, solidifying the adhesive, then etching the post to form a cavity in the adhesive above the post, then mounting a semiconductor device on the post, wherein a heat spreader includes the post and the base and the semiconductor device extends into the cavity, electrically connecting the semiconductor device to the substrate and thermally connecting the semiconductor device to the heat spreader.

Claims

1. A method of making a semiconductor chip assembly, comprising:

providing a post, a base, an adhesive and a conductive layer, wherein

the post is adjacent to the base, extends above the base in an upward direction, extends into an opening in the adhesive and is aligned with an aperture in the conductive layer,

the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions,

the adhesive is mounted on and extends above the base, is sandwiched between the base and the conductive layer and is non-solidified, and

the conductive layer is mounted on and extends above the adhesive;

then

flowing the adhesive into and upward in a gap located in the aperture between the post and the conductive layer;

solidifying the adhesive;

providing a conductive trace that includes a pad, a terminal and a selected portion of the conductive layer;

etching the post, thereby forming a cavity in the adhesive that is located above and extends to the post and faces in the upward direction;

then

mounting a semiconductor device on the post, wherein a heat spreader includes the post and the base and the semiconductor device overlaps the post and extends into the cavity;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal; and

thermally connecting the semiconductor device to the post, thereby thermally connecting the semiconductor device to the base.

2. The method of claim 1, wherein providing the post and the base includes:

providing a metal plate;

forming an etch mask on the metal plate that selectively exposes the metal plate;

etching the metal plate in a pattern defined by the etch mask, thereby forming a recess in the metal plate that extends into but not through the metal plate; and

then

removing the etch mask, wherein the post includes an unetched portion of the metal plate that protrudes above the base and is laterally surrounded by the recess, and the base includes an unetched portion of the metal plate below the post and the recess.

3. The method of claim 1, wherein:

providing the adhesive includes providing a prepreg with uncured epoxy;

flowing the adhesive includes melting the uncured epoxy and compressing the uncured epoxy between the base and the conductive layer; and

solidifying the adhesive includes curing the uncured epoxy.

4. The method of claim 1, wherein flowing the adhesive includes filling the gap with the adhesive.

5. The method of claim 1, wherein mounting the conductive layer includes mounting the conductive layer alone on the adhesive.

6. The method of claim 1, wherein mounting the conductive layer includes mounting the conductive layer and a dielectric layer on the adhesive.

7. The method of claim 1, wherein providing the conductive trace includes removing selected portions of the conductive layer after solidifying the adhesive.

8. The method of claim 1, wherein providing the pad includes removing selected portions of the conductive layer after solidifying the adhesive.

9. The method of claim 8, wherein forming the cavity includes etching the post after removing the selected portions of the conductive layer.

10. The method of claim 1, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the post, electrically connecting the semiconductor device includes providing a wire bond between the semiconductor device and the pad, and thermally connecting the semiconductor device includes providing the die attach between the semiconductor device and the post.

11. A method of making a semiconductor chip assembly, comprising:

providing a post and a base, wherein the post is adjacent to and integral with the base and extends above the base in an upward direction, and the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions;

providing an adhesive, wherein an opening extends through the adhesive;

providing a conductive layer, wherein an aperture extends through the conductive layer;

mounting the adhesive on the base, including inserting the post into the opening, wherein the adhesive extends above the base and the post extends into the opening;

mounting the conductive layer on the adhesive, including aligning the post with the aperture, wherein the conductive layer extends above the adhesive and the adhesive is sandwiched between the base and the conductive layer and is non-solidified;

then

applying heat to melt the adhesive;

moving the base and the conductive layer towards one another, thereby moving the post upward in the aperture and applying pressure to the molten adhesive between the base and the conductive layer, wherein the pressure forces the molten adhesive to flow into and upward in a gap located in the aperture between the post and the conductive layer;

applying heat to solidify the molten adhesive, thereby mechanically attaching the post and the base to the conductive layer;

then

providing a conductive trace that includes a pad and a terminal, wherein the conductive trace includes selected portions of the conductive layer and an electrically conductive path is between the pad and the terminal;

etching the post, thereby forming a cavity in the adhesive that is located above and extends to the post and faces in the upward direction;

then

mounting a semiconductor device on the post, wherein a heat spreader includes the post and the base and the semiconductor device overlaps the post and extends into the cavity;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal; and

thermally connecting the semiconductor device to the post, thereby thermally connecting the semiconductor device to the base.

12. The method of claim 11, wherein providing the post and the base includes:

providing a metal plate;

forming an etch mask on the metal plate that selectively exposes the metal plate;

etching the metal plate in a pattern defined by the etch mask, thereby forming a recess in the metal plate that extends into but not through the metal plate; and

then

removing the etch mask, wherein the post includes an unetched portion of the metal plate that protrudes above the base and is laterally surrounded by the recess, and the base includes an unetched portion of the metal plate below the post and the recess.

13. The method of claim 11, wherein:

providing the adhesive includes providing a prepreg with uncured epoxy;

flowing the adhesive includes melting the uncured epoxy and compressing the uncured epoxy between the base and the conductive layer; and

solidifying the adhesive includes curing the uncured epoxy.

14. The method of claim 11, wherein mounting the conductive layer includes mounting the conductive layer alone on the adhesive.

15. The method of claim 11, wherein mounting the conductive layer includes mounting the conductive layer and a dielectric layer on the adhesive.

16. The method of claim 11, wherein providing the pad includes removing selected portions of the conductive layer using an etch mask that defines the pad.

17. The method of claim 16, wherein forming the cavity includes etching the post after removing the selected portions of the conductive layer.

18. The method of claim 11, wherein providing the pad includes:

grinding the post, the adhesive and the conductive layer such that the post, the adhesive and the conductive layer are laterally aligned with one another at a top lateral surface that faces in the upward direction; and

then

removing selected portions of the conductive layer using an etch mask that defines the pad.

19. The method of claim 18, wherein forming the cavity includes etching the post after removing the selected portions of the conductive layer.

20. The method of claim 11, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the post, electrically connecting the semiconductor device includes providing a wire bond between the semiconductor device and the pad, and thermally connecting the semiconductor device includes providing the die attach between the semiconductor device and the post.

21. A method of making a semiconductor chip assembly, comprising:

providing a post, a base, an adhesive and a substrate, wherein

the substrate includes a conductive layer and a dielectric layer,

the post is adjacent to the base, extends above the base in an upward direction, extends through an opening in the adhesive and extends into an aperture in the substrate,

the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions,

the adhesive is mounted on and extends above the base, is sandwiched between the base and the substrate and is non-solidified,

the substrate is mounted on and extends above the adhesive, and the conductive layer extends above the dielectric layer, and

a gap is located in the aperture between the post and the substrate;

then

flowing the adhesive into and upward in the gap;

solidifying the adhesive;

then

etching the post, thereby forming a cavity in the adhesive that is located above and extends to the post and faces in the upward direction;

then

mounting a semiconductor device on the post, wherein a heat spreader includes the post and the base, the semiconductor device overlaps the post and extends into the cavity, a conductive trace includes a pad, a terminal and a selected portion of the conductive layer and the pad is electrically connected to the terminal;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal; and

thermally connecting the semiconductor device to the post, thereby thermally connecting the semiconductor device to the base.

22. The method of claim 21, wherein providing the post and the base includes:

providing a metal plate;

forming an etch mask on the metal plate that selectively exposes the metal plate;

etching the metal plate in a pattern defined by the etch mask, thereby forming a recess in the metal plate that extends into but not through the metal plate; and

then

removing the etch mask, wherein the post includes an unetched portion of the metal plate that protrudes above the base and is laterally surrounded by the recess, and the base includes an unetched portion of the metal plate below the post and the recess.

23. The method of claim 21, wherein:

providing the adhesive includes providing a prepreg with uncured epoxy;

flowing the adhesive includes melting the uncured epoxy and compressing the uncured epoxy between the base and the substrate; and

solidifying the adhesive includes curing the uncured epoxy.

24. The method of claim 21, wherein flowing the adhesive includes filling the gap with the adhesive.

25. The method of claim 21, wherein providing the conductive trace includes removing selected portions of the conductive layer after solidifying the adhesive.

26. The method of claim 21, wherein providing the pad includes removing selected portions of the conductive layer after solidifying the adhesive.

27. The method of claim 21, wherein providing the pad includes:

grinding the post, the adhesive and the conductive layer such that the post, the adhesive and the conductive layer are laterally aligned with one another at a top lateral surface that faces in the upward direction; and

then

removing selected portions of the conductive layer using an etch mask that defines the pad.

28. The method of claim 21, wherein providing the terminal includes removing selected portions of the base after solidifying the adhesive.

29. The method of claim 21, wherein forming the cavity includes etching the post after removing selected portions of the conductive layer.

30. The method of claim 21, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the post, electrically connecting the semiconductor device includes providing a wire bond between the semiconductor device and the pad, and thermally connecting the semiconductor device includes providing the die attach between the semiconductor device and the post.

31. A method of making a semiconductor chip assembly, comprising:

providing a post and a base, wherein the post is adjacent to and integral with the base and extends above the base in an upward direction, and the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions;

providing an adhesive, wherein an opening extends through the adhesive;

providing a substrate that includes a conductive layer and a dielectric layer, wherein an aperture extends through the substrate;

mounting the adhesive on the base, including inserting the post through the opening, wherein the adhesive extends above the base and the post extends through the opening;

mounting the substrate on the adhesive, including inserting the post into the aperture, wherein the substrate extends above the adhesive, the conductive layer extends above the dielectric layer, the post extends through the opening into the aperture, the adhesive is sandwiched between the base and the substrate and is non-solidified, and a gap is located in the aperture between the post and the substrate;

then

applying heat to melt the adhesive;

moving the base and the substrate towards one another, thereby moving the post upward in the aperture and applying pressure to the molten adhesive between the base and the substrate, wherein the pressure forces the molten adhesive to flow into and upward in the gap and the post and the molten adhesive extend above the dielectric layer;

applying heat to solidify the molten adhesive, thereby mechanically attaching the post and the base to the substrate;

then

etching the post, thereby forming a cavity in the adhesive that is located above and extends to the post and faces in the upward direction;

then

mounting a semiconductor device on the post, wherein a heat spreader includes the post and the base, the semiconductor device overlaps the post and is located within the cavity, a conductive trace includes a pad, a terminal and a selected portion of the conductive layer and the pad is electrically connected to the terminal;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal; and

thermally connecting the semiconductor device to the post, thereby thermally connecting the semiconductor device to the base.

32. The method of claim 31, wherein providing the post and the base includes:

providing a metal plate;

forming an etch mask on the metal plate that selectively exposes the metal plate;

etching the metal plate in a pattern defined by the etch mask, thereby forming a recess in the metal plate that extends into but not through the metal plate; and

then

removing the etch mask, wherein the post includes an unetched portion of the metal plate that protrudes above the base and is laterally surrounded by the recess, and the base includes an unetched portion of the metal plate below the post and the recess.

33. The method of claim 31, wherein:

providing the adhesive includes providing a prepreg with uncured epoxy;

flowing the adhesive includes melting the uncured epoxy and compressing the uncured epoxy between the base and the substrate; and

solidifying the adhesive includes curing the uncured epoxy.

34. The method of claim 31, wherein providing the pad includes removing selected portions of the conductive layer using an etch mask that defines the pad after solidifying the adhesive.

35. The method of claim 31, wherein providing the pad includes:

grinding the post, the adhesive and the conductive layer such that the post, the adhesive and the conductive layer are laterally aligned with one another at a top lateral surface that faces in the upward direction; and

then

removing selected portions of the conductive layer using an etch mask that defines the pad.