Method of making a semiconductor chip assembly with a post/base heat spreader and an adhesive between the base and a terminal

• US 8,227,270 B2
• Filed: 07/12/2010
• Issued: 07/24/2012
• 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
• Primary Examiner(s): Nguyen, Dao H
• Assistant Examiner(s): Nguyen, Tram H
• Application Number:
  US12/834,013
• Publication Number:
  US 20110039357A1
• Time in Patent Office: 743 Days
• Field of Search: 257/428, 257/99, 257/E33.056, 257/E33.066, 257/E23.101, 257/E23.01, 257/707, 257/713, 257/784, 257/684, 438/612
• US Class Current: 438/26
• CPC Class Codes: H01L 21/486 Via connections through the substrate with or without pins
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32013 the layer connector being larger than the bonding area, e.g. bond pad
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• 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 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take precedence
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

A method of making a semiconductor chip assembly includes providing a thermal post, a signal post, a base and a terminal, mounting an adhesive on the base including inserting the thermal post into a first opening in the adhesive and the signal post into a second opening in the adhesive, mounting a conductive layer on the adhesive including aligning the thermal post with a first aperture in the conductive layer and the signal post with a second aperture in the conductive layer, then flowing the adhesive upward between the thermal post and the conductive layer and between the signal post and the conductive layer and downward between the base and the terminal, solidifying the adhesive, providing a conductive trace that includes a pad, the terminal and the signal post, wherein the pad includes a selected portion of the conductive layer, mounting a semiconductor device on a heat spreader that includes the thermal post and the base, electrically connecting the semiconductor device to the conductive trace and thermally connecting the semiconductor device to the heat spreader.

Claims

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

providing a thermal post, a signal post, a base, a terminal, an adhesive and a conductive layer, wherein

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

the signal post is adjacent to the terminal, extends above the terminal in the upward direction, extends into a second opening in the adhesive and is aligned with a second aperture in the conductive layer,

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

the terminal extends below the signal post in the downward direction and extends laterally from the signal post in the lateral directions,

the adhesive is mounted on and extends above the base and the terminal, is sandwiched between the base and the conductive layer and between the terminal 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 first gap located in the first aperture between the thermal post and the conductive layer and in a second gap located in the second aperture between the signal post and the conductive layer;

flowing the adhesive into and downward in a slot between the base and the terminal;

solidifying the adhesive;

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

mounting a semiconductor device on a heat spreader that includes the thermal post and the base, wherein the semiconductor device overlaps the thermal post;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal, wherein an electrically conductive path between the pad and the terminal includes the signal post; and

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

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

providing a metal plate;

removing selected portions of the metal plate using a first etch mask that defines the posts;

removing selected portions of the metal plate using a second etch mask that defines the slot; and

removing the etch masks.

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 between the terminal 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 gaps and the slot 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 pad includes removing selected portions of the conductive layer after solidifying the adhesive.

8. The method of claim 1, wherein providing the pad includes:

grinding the posts, the adhesive and the conductive layer such that the posts, 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.

9. The method of claim 1, wherein providing the heat spreader includes providing a cap on the thermal post that extends above and is adjacent to and covers in the upward direction and extends laterally in the lateral directions from a top of the thermal post and that overlaps and is adjacent to the adhesive after solidifying the adhesive and before mounting the semiconductor device.

10. The method of claim 1, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the heat spreader, 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 heat spreader.

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

providing a metal plate that includes a thermal post, a signal post, a base and a terminal, wherein the thermal post is adjacent to and integral with the base and extends above the base in an upward direction, the signal post is adjacent to and integral with the terminal and extends above the terminal in the upward direction, the base extends below the thermal post in a downward direction opposite the upward direction and extends laterally from the thermal post in lateral directions orthogonal to the upward and downward directions, the terminal extends below the signal post in the downward direction and extends laterally from the signal post in the lateral directions and a slot extends through the metal plate between the base and the terminal, thereby providing edges of the base and the terminal that face towards one another;

providing an adhesive, wherein first and second openings extend through the adhesive;

providing a conductive layer, wherein first and second apertures extend through the conductive layer;

mounting the adhesive on the base and the terminal, including inserting the thermal post into the first opening and the signal post into the second opening, wherein the adhesive extends above the base and the terminal, the thermal post extends into the first opening and the signal post extends into the second opening;

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

then

applying heat to melt the adhesive;

moving the base and the terminal towards the conductive layer, thereby moving the thermal post upward in the first aperture, moving the signal post upward in the second aperture and applying pressure to the molten adhesive between the base and the conductive layer and between the terminal and the conductive layer, wherein the pressure forces the molten adhesive to flow into and upward in a first gap located in the first aperture between the thermal post and the conductive layer and in a second gap located in the second aperture between the signal post and the conductive layer, and the pressure forces the molten adhesive to flow into and downward in the slot between the base and the terminal;

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

then

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

removing selected portions of the metal plate, thereby providing additional edges of the base and the terminal;

then

mounting a semiconductor device on a heat spreader that includes the thermal post and the base, wherein the semiconductor device overlaps the thermal post;

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

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

forming a first etch mask on a first surface of the metal plate that selectively exposes the metal plate and defines the posts;

forming a second etch mask on a second surface of the metal plate opposite the first surface that selectively exposes the metal plate and defines the slot, thereby defining the edges of the base and the terminal that face towards one another;

then

etching the metal plate in patterns defined by the etch masks, thereby forming a recess in the metal plate that extends into but not through the metal plate and is adjacent to the posts and the slot which is overlapped by the recess, extends through a recessed portion of the metal plate and is adjacent to the base and the terminal; and

then

removing the etch masks.

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 between the terminal 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 after solidifying the adhesive.

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

grinding the posts, the adhesive and the conductive layer such that the posts, 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.

18. The method of claim 11, wherein providing the conductive trace and the heat spreader includes:

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

then

depositing a second conductive layer on the posts, the adhesive and the conductive layer;

forming an etch mask on the second conductive layer;

etching the conductive layers using the etch mask to define the pad;

etching the second conductive layer using the etch mask to define a cap that is adjacent to and overlaps the thermal post; and

then

removing the etch mask, wherein the heat spreader includes the cap.

19. The method of claim 11, wherein providing the conductive trace and the heat spreader includes:

grinding the base, the terminal and the adhesive such that the base, the terminal and the adhesive are laterally aligned with one another at a bottom lateral surface that faces in the downward direction; and

then

providing the additional edges of the base and the terminal.

20. The method of claim 11, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the heat spreader, 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 heat spreader.

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

providing a thermal post, a signal post, a base, a terminal, an adhesive and a substrate, wherein

the thermal post is adjacent to the base, extends above the base in an upward direction, extends into a first opening in the adhesive and is aligned with a first aperture in the substrate,

the signal post is adjacent to the terminal, extends above the terminal in the upward direction, extends into a second opening in the adhesive and is aligned with a second aperture in the substrate,

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

the terminal extends below the signal post in a downward direction opposite the upward direction and extends laterally from the signal post in the lateral directions,

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

the substrate is mounted on and extends above the adhesive, wherein the substrate includes a conductive layer and a dielectric layer and the conductive layer extends above the dielectric layer;

then

flowing the adhesive into and upward in a first gap located in the first aperture between the thermal post and the substrate and in a second gap located in the second aperture between the signal post and the substrate;

flowing the adhesive into and downward in a slot between the base and the terminal, wherein the slot provides edges of the base and the terminal that face towards one another;

solidifying the adhesive;

then

providing a conductive trace that includes a pad, the terminal and the signal post, wherein the pad extends above the signal post and includes a selected portion of the conductive layer;

providing additional edges of the base and the terminal;

then

mounting a semiconductor device on a heat spreader that includes the thermal post and the base, wherein the semiconductor device overlaps the thermal post;

electrically connecting the semiconductor device to the pad, thereby electrically connecting the semiconductor device to the terminal, wherein an electrically conductive path between the pad and the terminal includes the signal post; and

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

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

providing a metal plate;

removing selected portions of the metal plate using a first etch mask that defines the posts;

removing selected portions of the metal plate using a second etch mask that defines the slot; and

removing the etch masks.

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 between the terminal 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 gaps and the slot with the adhesive.

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

26. The method of claim 21, wherein providing the conductive trace includes:

grinding the posts, the adhesive and the conductive layer such that the posts, 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.

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

grinding the base, the terminal and the adhesive such that the base, the terminal and the adhesive are laterally aligned with one another at a bottom lateral surface that faces in the downward direction; and

then

providing the additional edges of the terminal.

28. The method of claim 21, wherein providing the heat spreader includes:

grinding the base, the terminal and the adhesive such that the base, the terminal and the adhesive are laterally aligned with one another at a bottom lateral surface that faces in the downward direction; and

then

providing the additional edges of the base.

29. The method of claim 21, wherein providing the heat spreader includes providing a cap on the thermal post that extends above and is adjacent to and covers in the upward direction and extends laterally in the lateral directions from a top of the thermal post and that overlaps and is adjacent to the adhesive after solidifying the adhesive and before mounting the semiconductor device.

30. The method of claim 21, wherein mounting the semiconductor device includes providing a die attach between the semiconductor device and the heat spreader, 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 heat spreader.

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

providing a metal plate that includes a thermal post, a signal post, a base and a terminal, wherein the thermal post is adjacent to and integral with the base and extends above the base in an upward direction, the signal post is adjacent to and integral with the terminal and extends above the terminal in the upward direction, the base extends below the thermal post in a downward direction opposite the upward direction and extends laterally from the thermal post in lateral directions orthogonal to the upward and downward directions, the terminal extends below the signal post in the downward direction and extends laterally from the signal post in the lateral directions and a slot extends through the metal plate between the base and the terminal, thereby providing edges of the base and the terminal that face towards one another;

providing an adhesive, wherein first and second openings extend through the adhesive;

providing a substrate that includes a first conductive layer and a dielectric layer, wherein first and second apertures extend through the substrate;

mounting the adhesive on the base and the terminal, including inserting the thermal post into the first opening and the signal post into the second opening, wherein the adhesive extends above the base and the terminal, the thermal post extends through the first opening and the signal post extends through the second opening;

mounting the substrate on the adhesive, including aligning the thermal post with the first aperture and the signal post with the second aperture, wherein the substrate extends above the adhesive, the first conductive layer extends above the dielectric layer and the adhesive is sandwiched between the base and the substrate and between the terminal and the substrate and is non-solidified;

then

applying heat to melt the adhesive;

moving the base and the terminal towards and the substrate, thereby moving the thermal post upward in the first aperture, moving the signal post upward in the second aperture and applying pressure to the molten adhesive between the base and the substrate and between the base and the terminal, wherein the pressure forces the molten adhesive to flow into and upward in a first gap located in the first aperture between the thermal post and the substrate and in a second gap located in the second aperture between the signal post and the substrate, and the pressure forces the molten adhesive to flow into and downward in the slot between the base and the terminal;

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

then

depositing a second conductive layer on the posts, the adhesive and the first conductive layer;

then

providing a pad that includes a selected portion of the conductive layers, including removing selected portions of the conductive layers, wherein the pad extends above and is adjacent to and covers in the upward direction and extends laterally in the lateral directions from a top of the signal post and an electrically conductive path between the pad and the terminal includes the signal post;

providing a cap on the thermal post that includes a selected portion of the second conductive layer, including removing selected portions of the second conductive layer, wherein the cap extends above and is adjacent to and covers in the upward direction and extends laterally in the lateral directions from a top of the thermal post and a thermally conductive path between the cap and the base includes the thermal post;

removing selected portions of the metal plate, thereby providing additional edges of the base and the terminal;

then

mounting a semiconductor device on the cap, wherein the semiconductor device overlaps the thermal post and a heat spreader includes the thermal post, the base and the cap;

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

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

forming a first etch mask on a first surface of the metal plate that selectively exposes the metal plate and defines the posts;

forming a second etch mask on a second surface of the metal plate opposite the first surface that selectively exposes the metal plate and defines the slot, thereby defining the edges of the base and the terminal that face towards one another;

then

etching the metal plate in patterns defined by the etch masks, thereby forming a recess in the metal plate that extends into but not through the metal plate and is adjacent to the posts and the slot which is overlapped by the recess, extends through a recessed portion of the metal plate and is adjacent to the base and the terminal; and

then

removing the etch masks.

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 between the terminal and the substrate; and

solidifying the adhesive includes curing the uncured epoxy.

34. The method of claim 31, wherein providing the pad and the cap includes:

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

then

depositing the second conductive layer on the posts, the adhesive and the first conductive layer;

forming an etch mask on the second conductive layer;

etching the conductive layers using the etch mask to define the pad;

etching the second conductive layer using the etch mask to define the cap; and

then

removing the etch mask.

35. The method of claim 31, wherein mounting the semiconductor device includes providing a die attach between an LED chip and the cap, electrically connecting the semiconductor device includes providing a wire bond between the LED chip and the pad, and thermally connecting the semiconductor device includes providing the die attach between the LED chip and the cap.