US5907474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-profile heat transfer apparatus for a surface-mounted semiconductor device employing a ball grid array (BGA) device package
Assignee: GlobalFoundries Inc
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Filing: 1997-04-25
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Granted: 1999-05-25
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Expires: 2017-04-25
Abstract
Abstract A low-profile heat transfer apparatus is presented for a surface-mounted semiconductor device employing a ball grid array (BGA) device package having a chip mounted upon a substantially flat upper surface of a substrate. The semiconductor device is mounted upon a component side of a printed circuit board (PCB), and the heat transfer apparatus is used to transfer heat energy from the semiconductor device to an ambient. A thermally conductive cap structure is positioned between the semiconductor device and the ambient. The cap structure includes a bottom surface having a first cavity sized to receive the substrate and possibly any decoupling capacitors. During use, the substrate resides within the first cavity. In a first embodiment, the chip resides within a second cavity in an upper wall of the first cavity during use. The chip and substrate are thermally coupled to the cap structure by a first and second thermal interface layer, respectively. The use of two thermal interface layers achieves a relatively low value of θ JS , allowing the cap structure to remain relatively small. In a second embodiment, the chip resides within a hole in the cap structure during use such that the upper surface of the chip is exposed to the ambient. The substrate is thermally coupled to the cap structure by a thermal interface layer. The achieved value of θ JS is acceptably low for some applications, and the height of the cap structure relative to the component side of the PCB is substantially reduced.
Inventors
- 👤 Thomas P. Dolbear
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:40
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/30; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/325; H05K7/00; H05K7/02; H05K7/10; H05K7/1053; H05K7/1061; H10W40/00; H10W40/60; H10W40/611; H10W40/70; H10W40/77; H10W76/00; H10W76/10; H10W76/12; H05K1/00; H05K1/02; H05K1/0201; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H10W72/01; H10W72/013; H10W72/01308; H10W72/071; H10W72/072; H10W72/07251; H10W72/073; H10W72/07311; H10W72/20; H10W72/381; H10W72/851; H10W72/874; H10W72/877
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
124 words
A heat transfer apparatus, comprising: a thermally conductive cap secured directly via fasteners to a printed circuit board (PCB) about an integrated circuit and a substrate upon which the integrated circuit resides; said cap comprising a first lower surface elevationally lowered below a second lower surface, wherein the first lower surface is spaced a first distance above the substrate laterally outside a perimeter of the integrated circuit and the second lower surface is spaced a second distance above the integrated circuit; wherein the first lower surface is in thermal communication with a portion of an upper surface of the substrate a lateral distance from a perimeter of the integrated circuit; and wherein the second lower surface is in thermal communication iwth the integrated circuit.
Claim 2
Dependent Claim
124 words
A heat transfer apparatus, comprising: a thermally conductive cap secured directly via fasteners to a printed circuit board (PCB) about an integrated circuit and a substrate upon which the integrated circuit resides; said cap comprising a first lower surface elevationally lowered below a second lower surface, wherein the first lower surface is spaced a first distance above the substrate laterally outside a perimeter of the integrated circuit and the second lower surface is spaced a second distance above the integrated circuit; wherein the first lower surface is in thermal communication with a portion of an upper surface of the substrate a lateral distance from a perimeter of the integrated circuit; and wherein the second lower surface is in thermal communication iwth the integrated circuit.
Claim 3
Dependent Claim
34 words
The heat transfer apparatus as recited in claim 1, wherein said first and second lower surfaces are separated by a wall which extends along a vertical axis a lateral distance from the integrated circuit.
Claim 4
Dependent Claim
18 words
The heat transfer apparatus as recited in claim 1, wherein said first and second distances are substantially equal.
Claim 5
Dependent Claim
38 words
The heat transfer apparatus as recited in claim 1, further comprising a thermal interface layer secured in the space defined by the first distance and another thermal interface layer secured in the spaced defined by the second distance.
Claim 6
Dependent Claim
28 words
The heat transfer apparatus as recited in claim 1, wherein both of the thermal interface layers comprise a plurality of thermally conductive particles suspended in a wax base.
Claim 7
Dependent Claim
31 words
The heat transfer apparatus as recited in claim 1, wherein the first lower surface defines an upper wall of a first cavity which surrounds at least a portion of the substrate.
Claim 8
Dependent Claim
32 words
The heat transfer apparatus as recited in claim 1, wherein the second lower surface defines an upper wall of a second cavity which surrounds at least a portion of the integrated circuit.
Claim 9
Dependent Claim
14 words
The heat transfer apparatus as recited in claim 1, wherein the cap comprises aluminum.
Claim 10
Dependent Claim
35 words
The heat transfer apparatus as recited in claim 1, wherein said fastener extends through the cap and the PCB and into a backing plate configured on a side of the PCB opposite the integrated circuit.
Claim 11
Dependent Claim
25 words
The heat transfer apparatus as recited in claim 9, wherein the fastener comprises means for compressing said PCB between the cap and the backing plate.
Claim 12
Dependent Claim
46 words
The heat transfer apparatus as recited in claim 10, wherein the substrate is bonded to the PCB, the integrated circuit is bonded to the substrate, and the combination of the integrated circuit and the substrate are compressed between the cap and the PCB by the fastener.
Claim 13
Dependent Claim
35 words
The heat transfer apparatus as recited in claim 10, wherein during use the fastener exerts a force between the backing plate and the cap which urges the cap toward the integrated circuit and the substrate.
Claim 14
Dependent Claim
32 words
The heat transfer apparatus as recited in claim 9, further comprising a thermal interface layer interposed between the backing plate and the PCB for thermally coupling the PCB to the backing plate.
Claim 15
Dependent Claim
25 words
The heat transfer apparatus as recited in claim 13, wherein the thermal interface layer comprises a plurality of thermally conductive particles within an elastomeric compound.
Claim 16
Dependent Claim
227 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and both the integrated circuit and the substrate, wherein said cap has a first cavity and a second cavity elevationally raised above a central portion of the first cavity; a thermally conductive backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; said fasteners also attaching the backing plate to the cap; a first thermal interface layer interposed between the integrated circuit and a ceiling of the second cavity, wherein the first thermal interface layer thermally couples the integrated circuit to the cap; a second thermal interface layer interposed between the substrate and a ceiling of the first cavity a lateral distance from a perimeter of the integrated circuit, wherein the second thermal interface layer thermally couples the substrate to the cap; a third thermal interface layer interposed between the backing plate and the PCB, wherein the third thermal interface layer thermally couples the PCB to the backing plate; and a seal, wherein the seal is interposed between a perimeter of a bottom surface of the cap and the PCB.
Claim 17
Dependent Claim
227 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and both the integrated circuit and the substrate, wherein said cap has a first cavity and a second cavity elevationally raised above a central portion of the first cavity; a thermally conductive backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; said fasteners also attaching the backing plate to the cap; a first thermal interface layer interposed between the integrated circuit and a ceiling of the second cavity, wherein the first thermal interface layer thermally couples the integrated circuit to the cap; a second thermal interface layer interposed between the substrate and a ceiling of the first cavity a lateral distance from a perimeter of the integrated circuit, wherein the second thermal interface layer thermally couples the substrate to the cap; a third thermal interface layer interposed between the backing plate and the PCB, wherein the third thermal interface layer thermally couples the PCB to the backing plate; and a seal, wherein the seal is interposed between a perimeter of a bottom surface of the cap and the PCB.
Claim 18
Dependent Claim
16 words
The heat transfer apparatus as recited in claim 15, wherein the seal comprises an elastomeric compound.
Claim 19
Dependent Claim
130 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured directly via fasteners to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the cap is in thermal communication with the substrate, and wherein the integrated circuit resides within the hole such that an entire upper surface of the integrated circuit is exposed to the ambient.
Claim 20
Dependent Claim
130 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured directly via fasteners to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the cap is in thermal communication with the substrate, and wherein the integrated circuit resides within the hole such that an entire upper surface of the integrated circuit is exposed to the ambient.
Claim 21
Dependent Claim
27 words
The heat transfer apparatus as recited in claim 17, wherein the ceiling is spaced a distance above the substrate laterally outside a perimeter of the integrated circuit.
Claim 22
Dependent Claim
20 words
The heat transfer apparatus as recited in claim 17, wherein the ceiling surrounds at least a portion of the substrate.
Claim 23
Dependent Claim
14 words
The heat transfer apparatus as recited in claim 17, wherein the cap comprises aluminum.
Claim 24
Dependent Claim
32 words
The heat transfer apparatus as recited in claim 17, further comprising a thermal interface layer interposed between the substrate and the ceiling a lateral distance from a perimeter of the integrated circuit.
Claim 25
Dependent Claim
26 words
The heat transfer apparatus as recited in claim 21, wherein the thermal interface layer comprises a plurality of thermally conductive particles suspended in a wax base.
Claim 26
Dependent Claim
159 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the cap is in thermal communication with the substrate, and wherein the integrated circuit resides within the hole such that an upper surface of the integrated circuit is exposed to the ambient; a backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; and said fasteners also attaching the backing plate to the cap.
Claim 27
Dependent Claim
159 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the cap is in thermal communication with the substrate, and wherein the integrated circuit resides within the hole such that an upper surface of the integrated circuit is exposed to the ambient; a backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; and said fasteners also attaching the backing plate to the cap.
Claim 28
Dependent Claim
230 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the integrated circuit resides within the hole such that an upper surface of the integrated circuit is exposed to the ambient; a backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; said fasteners also attaching the backing plate to the cap; a first thermal interface layer interposed between the substrate and the ceiling a lateral distance from a perimeter of the integrated circuit, wherein the first thermal interface layer thermally couples the substrate to the cap; a second thermal interface layer interposed between the backing plate and the PCB, wherein the second thermal interface layer thermally couples the PCB to the backing plate; and a seal, wherein the seal is interposed between a perimeter of the bottom surface of the cap and the PCB.
Claim 29
Dependent Claim
230 words
A heat transfer apparatus transferring heat energy from an integrated circuit to an ambient, wherein the integrated circuit is mounted to a substrate secured to a printed circuit board (PCB), the heat transfer apparatus comprising: a thermally conductive cap secured directly via fasteners to the PCB between the ambient and the substrate, wherein said cap comprises opposed top and bottom surfaces, and wherein the bottom surface comprises a cavity having a ceiling, and wherein the cap comprises a hole substantially in the center of the ceiling and extending from the ceiling to the top surface, and wherein the integrated circuit resides within the hole such that an upper surface of the integrated circuit is exposed to the ambient; a backing plate, wherein the backing plate is positioned on a side of the PCB opposite the integrated circuit; said fasteners also attaching the backing plate to the cap; a first thermal interface layer interposed between the substrate and the ceiling a lateral distance from a perimeter of the integrated circuit, wherein the first thermal interface layer thermally couples the substrate to the cap; a second thermal interface layer interposed between the backing plate and the PCB, wherein the second thermal interface layer thermally couples the PCB to the backing plate; and a seal, wherein the seal is interposed between a perimeter of the bottom surface of the cap and the PCB.
Claim 30
Dependent Claim
16 words
The heat transfer apparatus as recited in claim 24, wherein the seal comprises an elastomeric compound.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-24 | 2010-11-23 | 2011-05-25 | $7700.00 | Window Closed / Lapsed |