U.S. patent application number 12/711455 was filed with the patent office on 2011-08-25 for double-face heat removal of vertically integrated chip-stacks utilizing combined symmetric silicon carrier fluid cavity and micro-channel cold plate.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. Invention is credited to Paul S. Andry, Thomas J. Brunschwiler, Evan G. Colgan, John H. Magerlein.
Application Number | 20110205708 12/711455 |
Document ID | / |
Family ID | 44314385 |
Filed Date | 2011-08-25 |
United States Patent
Application |
20110205708 |
Kind Code |
A1 |
Andry; Paul S. ; et
al. |
August 25, 2011 |
DOUBLE-FACE HEAT REMOVAL OF VERTICALLY INTEGRATED CHIP-STACKS
UTILIZING COMBINED SYMMETRIC SILICON CARRIER FLUID CAVITY AND
MICRO-CHANNEL COLD PLATE
Abstract
A plurality of heat-dissipating electronic chips are arranged in
a vertical chip stack. The electronic chips have electronic
components thereon. A cold plate is secured to a back side of the
chip stack. A silicon carrier sandwich, defining a fluid cavity, is
secured to a front side of the chip stack. An inlet manifold is
configured to supply cooling fluid to the cold plate and the fluid
cavity of the silicon carrier sandwich. An outlet manifold is
configured to receive the cooling fluid from the cold plate and the
fluid cavity of the silicon carrier sandwich. The cold plate, the
silicon carrier sandwich, the inlet manifold, and the outlet
manifold are configured and dimensioned to electrically isolate the
cooling fluid from the electronic components. A method of operating
an electronic apparatus and a method of manufacturing an electronic
apparatus are also disclosed. Single-sided heat removal with
double-sided electrical input-output and double-sided heat removal
with double-sided electrical input-output are also disclosed.
Inventors: |
Andry; Paul S.; (Yorktown
Heights, NY) ; Brunschwiler; Thomas J.; (Thalwil,
CH) ; Colgan; Evan G.; (Chestnut Ridge, NY) ;
Magerlein; John H.; (Yorktown Heights, NY) |
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
44314385 |
Appl. No.: |
12/711455 |
Filed: |
February 24, 2010 |
Current U.S.
Class: |
361/702 ;
257/E21.499; 438/122 |
Current CPC
Class: |
H01L 23/147 20130101;
H01L 23/481 20130101; H01L 2924/00014 20130101; H01L 2924/15311
20130101; H01L 2225/06517 20130101; H01L 23/473 20130101; H01L
2225/06513 20130101; H01L 2924/00014 20130101; H01L 2225/06589
20130101; H01L 23/49827 20130101; H01L 23/3677 20130101; H01L
25/0657 20130101; H01L 2224/16227 20130101; H01L 2924/10253
20130101; H01L 2224/16225 20130101; H01L 2924/10253 20130101; H01L
2924/00 20130101; H01L 2224/0401 20130101; H01L 2225/06541
20130101 |
Class at
Publication: |
361/702 ;
438/122; 257/E21.499 |
International
Class: |
H05K 7/20 20060101
H05K007/20; H01L 21/50 20060101 H01L021/50 |
Claims
1. An apparatus comprising: a plurality of heat-dissipating
electronic chips arranged in a vertical chip stack, said electronic
chips having electronic components thereon; a cold plate secured to
a back side of said chip stack; a silicon carrier sandwich,
defining a fluid cavity, secured to a front side of said chip
stack; an inlet manifold configured to supply cooling fluid to said
cold plate and said fluid cavity of said silicon carrier sandwich;
and an outlet manifold configured to receive said cooling fluid
from said cold plate and said fluid cavity of said silicon carrier
sandwich; wherein said cold plate, said silicon carrier sandwich,
said inlet manifold, and said outlet manifold are configured and
dimensioned to electrically isolate said cooling fluid from said
electronic components.
2. The apparatus of claim 1, wherein said silicon carrier sandwich
comprises upper and lower halves bonded together.
3. The apparatus of claim 2, wherein said silicon carrier sandwich
further comprises a plurality of pin fins within said fluid cavity,
configured to conduct heat from said chip stack into said cooling
fluid.
4. The apparatus of claim 3, wherein said pin fins have a circular
cross section.
5. The apparatus of claim 3, wherein said pin fins have a
drop-shaped cross section.
6. The apparatus of claim 3, wherein said pin fins are arranged in
uniform columns.
7. The apparatus of claim 3, wherein said pin fins are arranged in
staggered columns.
8. The apparatus of claim 3, wherein said pin fins have a pitch of
from about 100 to 200 microns and a height of from about 100 to 200
microns.
9. The apparatus of claim 2, wherein said silicon carrier sandwich
further comprises a plurality of plate fins within said fluid
cavity, configured to conduct heat from said chip stack into said
cooling fluid.
10. The apparatus of claim 2 wherein said silicon carrier sandwich
has a surface adjacent said vertical chip stack, further comprising
redistribution wiring provided on said surface of said silicon
carrier sandwich adjacent said vertical chip stack.
11. The apparatus of claim 1, further comprising: a pump to pump
said cooling fluid; and an external heat exchanger coupled to said
pump, said inlet manifold, and said outlet manifold, to cool said
cooling fluid via heat transfer to an external sink.
12. The apparatus of claim 1, further comprising: at least one
laminate structure secured to said silicon carrier sandwich; and at
least one optical component embedded in said laminate
structure.
13. The apparatus of claim 1, wherein said silicon carrier sandwich
comprises a first silicon carrier sandwich and said cold plate
comprises a second silicon carrier sandwich, further comprising: a
first series of electrical interconnects on a side of said first
silicon carrier sandwich opposite said chip stack; and a second
series of electrical interconnects on a side of said second silicon
carrier sandwich opposite said chip stack.
14. A method of operating an electronic apparatus, comprising:
providing an apparatus comprising: a plurality of heat-dissipating
electronic chips arranged in a vertical chip stack, said electronic
chips having electronic components thereon; a cold plate secured to
a back side of said chip stack; a silicon carrier sandwich,
defining a fluid cavity, secured to a front side of said chip
stack; an inlet manifold in fluid communication with said cold
plate and said fluid cavity of said silicon carrier sandwich; and
an outlet manifold in fluid communication with said cooling fluid
from said cold plate and said fluid cavity of said silicon carrier
sandwich; wherein said cold plate, said silicon carrier sandwich,
said inlet manifold, and said outlet manifold are configured and
dimensioned to electrically isolate said cooling fluid from said
electronic components; providing chilled cooling fluid to said
inlet manifold; and exhausting heated cooling fluid from said
outlet manifold.
15. A method of manufacturing an electronic apparatus, comprising:
providing a plurality of heat-dissipating electronic chips arranged
in a vertical chip stack, said electronic chips having electronic
components thereon; securing a cold plate to a back side of said
chip stack; securing a silicon carrier sandwich, defining a fluid
cavity, to a front side of said chip stack; assembling an inlet
manifold to said cold plate and said silicon carrier sandwich in
fluid communication with said cold plate and said fluid cavity of
said silicon carrier sandwich; and assembling an outlet manifold to
said cold plate and said silicon carrier sandwich in fluid
communication with said cold plate and said fluid cavity of said
silicon carrier sandwich.
16. The method of claim 15, further comprising bonding upper and
lower halves of said silicon carrier sandwich together to form said
silicon carrier sandwich.
17. The method of claim 16, further comprising forming a plurality
of pin fins within said fluid cavity, configured to conduct heat
from said chip stack into cooling fluid.
18. The method of claim 17, wherein, in said fin-forming step, said
pin fins have at least one of a circular cross section and a
drop-shaped cross section.
19. The method of claim 17, wherein, in said fin-forming step, said
pin fins are arranged in uniform columns.
20. The method of claim 17, wherein, in said fin-forming step, said
pin fins are arranged in staggered columns.
21. The method of claim 17, wherein, in said fin-forming step, said
pin fins have a pitch of from about 100 to 200 microns and a height
of from about 100 to 200 microns.
22. The method of claim 16, further comprising forming a plurality
of plate fins within said fluid cavity, configured to conduct heat
from said chip stack into cooling fluid.
23. The method of claim 15, further comprising: securing at least
one laminate structure to said silicon carrier sandwich; and
embedding at least one optical component in said laminate
structure.
24. An apparatus comprising: a plurality of heat-dissipating
electronic chips arranged in a vertical chip stack, said electronic
chips having electronic components thereon; a silicon carrier
sandwich, defining a fluid cavity, secured to a front side of said
chip stack; an inlet manifold configured to supply cooling fluid to
said fluid cavity of said silicon carrier sandwich; an outlet
manifold configured to receive said cooling fluid from said fluid
cavity of said silicon carrier sandwich; a first series of
electrical interconnects on a side of said silicon carrier sandwich
opposite said chip stack; and a second series of electrical
interconnects on a back side of said chip stack; wherein said
silicon carrier sandwich, said inlet manifold, and said outlet
manifold are configured and dimensioned to electrically isolate
said cooling fluid from said electronic components.
25. The apparatus of claim 24, wherein said silicon carrier
sandwich comprises upper and lower halves bonded together and a
plurality of fins within said fluid cavity, configured to conduct
heat from said chip stack into said cooling fluid.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the electronic and thermal
arts, and, more particularly, to thermal control of
electronics.
BACKGROUND OF THE INVENTION
[0002] A major challenge in vertically integrated high-performance
chip stack packages is their thermal management. With reference to
FIG. 1, the heat flux and thermal resistance accumulate with each
additional tier, or chip layer 102. Back-side heat removal with
attached air cooled heat sinks or high performance micro-channel
cold plates 104 similar to conventional single chip packages is
possible but very limited. This is because their heat removal
capability does not scale with the number of stacked dies 102 and
therefore limits the possible heat flux and the number of tiers 102
in the stack. Referring now to FIG. 2, interlayer-cooling is
another cooling technology, which does scale with the number of
tiers 102, but is very challenging to implement. Furthermore,
interlayer-cooling limits the possible interconnect density to a 50
micron pitch or more for large chips.
SUMMARY OF THE INVENTION
[0003] Principles of the present invention provide techniques for
double-face heat removal of vertically integrated chip-stacks
utilizing a combined symmetric silicon carrier fluid cavity and
micro-channel cold plate. In one aspect, an exemplary apparatus
includes a plurality of heat-dissipating electronic chips arranged
in a vertical chip stack. The electronic chips have electronic
components thereon. Also included are a cold plate secured to a
back side of the chip stack; a silicon carrier sandwich, defining a
fluid cavity, secured to a front side of the chip stack; an inlet
manifold configured to supply cooling fluid to the cold plate and
the fluid cavity of the silicon carrier sandwich; and an outlet
manifold configured to receive the cooling fluid from the cold
plate and the fluid cavity of the silicon carrier sandwich. The
cold plate, the silicon carrier sandwich, the inlet manifold, and
the outlet manifold are configured and dimensioned to electrically
isolate the cooling fluid from the electronic components.
[0004] In another aspect, an exemplary method of operating an
electronic apparatus includes the step of providing an apparatus
including a plurality of heat-dissipating electronic chips arranged
in a vertical chip stack (the electronic chips have electronic
components thereon); a cold plate secured to a back side of the
chip stack; a silicon carrier sandwich, defining a fluid cavity,
secured to a front side of the chip stack; an inlet manifold in
fluid communication with the cold plate and the fluid cavity of the
silicon carrier sandwich; and an outlet manifold in fluid
communication with the cooling fluid from the cold plate and the
fluid cavity of the silicon carrier sandwich. The cold plate, the
silicon carrier sandwich, the inlet manifold, and the outlet
manifold are configured and dimensioned to electrically isolate the
cooling fluid from the electronic components. Further steps include
providing chilled cooling fluid to the inlet manifold; and
exhausting heated cooling fluid from the outlet manifold.
[0005] In still another aspect, an exemplary method of
manufacturing an electronic apparatus includes the steps of
providing a plurality of heat-dissipating electronic chips arranged
in a vertical chip stack (the electronic chips have electronic
components thereon); securing a cold plate to a back side of the
chip stack; securing a silicon carrier sandwich, defining a fluid
cavity, to a front side of the chip stack; assembling an inlet
manifold to the cold plate and the silicon carrier sandwich in
fluid communication with the cold plate and the fluid cavity of the
silicon carrier sandwich; and assembling an outlet manifold to the
cold plate and the silicon carrier sandwich in fluid communication
with the cold plate and the fluid cavity of the silicon carrier
sandwich.
[0006] In yet another aspect, an exemplary apparatus includes a
plurality of heat-dissipating electronic chips arranged in a
vertical chip stack. The electronic chips have electronic
components thereon. Also included is a silicon carrier sandwich,
defining a fluid cavity, secured to a front side of the chip stack.
In an inlet manifold is configured to supply cooling fluid to the
fluid cavity of the silicon carrier sandwich, and an outlet
manifold is configured to receive the cooling fluid from the fluid
cavity of the silicon carrier sandwich. A first series of
electrical interconnects are on a side of the silicon carrier
sandwich opposite the chip stack. A second series of electrical
interconnects are on a back side of the chip stack. The silicon
carrier sandwich, the inlet manifold, and the outlet manifold are
configured and dimensioned to electrically isolate the cooling
fluid from the electronic components.
[0007] As used herein, "facilitating" an action includes performing
the action, making the action easier, helping to carry the action
out, or causing the action to be performed.
[0008] These and other features, aspects and advantages of the
present invention will become apparent from the following detailed
description of illustrative embodiments thereof, which is to be
read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a back-side-cooled 3-D package, according to
the prior art;
[0010] FIG. 2 shows convective interlayer heat removal, according
to the prior art;
[0011] FIG. 3 shows a cross-section through an exemplary
double-face cooled package, according to an aspect of the
invention;
[0012] FIG. 4 depicts details of silicon carrier bonding
technology, according to another aspect of the invention;
[0013] FIG. 5 depicts potential fluid cavity structures compatible
with through-silicon vias (TSV), according to yet another aspect of
the invention;
[0014] FIG. 6 shows a cross-section through another exemplary
double-face cooled package, similar to that in FIG. 3, but with
embedded optical communication, according to still another aspect
of the invention;
[0015] FIGS. 7-10 show cross-sectional views of various alternative
embodiments, including, respectively, double-faced heat removal
with single-sided input/output, double-faced heat removal with
double-sided input/output, single-faced heat removal with
double-sided input/output, and double-faced heat removal with
double-sided input/output.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0016] One or more embodiments of the invention provide double-face
stack cooling utilizing the silicon-carrier and a back-side cold
plate as heat absorbers, advantageously combining the strength of
the mentioned technologies at moderate complexity. Front-side
cooling using dielectric fluids pumped through the C4 (Controlled
Collapse Chip Connection) ball array has already been proposed.
However, limited heat removal capability is attained due to the
poor thermo-physical properties of these coolants, especially in
low height cavities, resulting in low heat flux capacity. The use
of the superior thermal properties of water was not possible due to
electro corrosion and shorting between solder balls. With the
symmetric silicon-carrier fluid cavity, according to one or more
embodiments of the invention, the electrical inputs and outputs
(I/Os) are insulated from the coolant, and therefore water can be
used. The industry calls these electrical interconnects "through
silicon vias" (TSV).
[0017] In one or more embodiments, to double the heat removal
capacity in thermally limited chip-stacks, both sides of the stack
are considered for heat transfer, as compared to backside cooling
only. At the backside a micro-channel cold plate is applied. It
connects to a symmetric silicon-carrier fluid cavity. Compared to
interlayer cooling, the complexity is drastically reduced since no
fluid has to be pumped through active layers with high interconnect
density. The moderate pitch of 100 to 200 microns and a symmetric
combination of two silicon carriers result in a large enough fluid
cavity with acceptable mass flow rate. At the same time, the warp
of the silicon carrier, which in an asymmetric configuration causes
difficulties during micro-bump bonding, is eliminated. The result
is a higher degree of freedom in chip stack design, especially in
number of tiers and heat flux levels at minimal complexity; and the
reduction of silicon carrier warp, increasing packaging yield.
Further, the fluid connections to the silicon carrier can be
provided from the back side cooler, rather than from the PCB.
[0018] In one or more embodiments, a plurality of heat-dissipating
electronic chips are arranged in a vertical chip stack and mounted
on a silicon carrier sandwich containing defined fluid cavities as
well as electrically isolated through-silicon vias (TSVs).
Two-sided chip stack cooling is achieved by employing a cold plate
secured to a back side of the chip stack, as well as by the silicon
carrier sandwich secured to the front (bottom or package) side of
the chip stack. An inlet manifold is configured to supply cooling
fluid to both the cold plate and the fluid cavity of the silicon
carrier sandwich, while an outlet manifold is configured to receive
the cooling fluid from both the cold plate and the fluid cavity of
the silicon carrier sandwich. The TSVs are constructed such that
electrical signals, power and ground connections are effectively
made from an underlying substrate or package to the chip stack
above, but in such a way that all connections are electrically
isolated from the cooling fluid flowing within the silicon carrier
sandwich. According to another aspect of the invention, the silicon
carrier sandwich comprises upper and lower halves bonded together
to form a stress-balanced symmetric sandwich with negligible warp
or bow. According to still another aspect of the invention, the
plurality of TSVs form pin fins within the fluid cavity, which are
configured to conduct heat from the chip stack into the cooling
fluid.
[0019] FIG. 3 is a cross-section through an exemplary embodiment of
a double-face cooled package. FIG. 4 depicts details of silicon
carrier bonding technology. Like elements have the same number.
Arrows 320 indicate coolant flow, while arrows 322 represent heat
flux. Two silicon carriers 324 with etched channel or pin-fin
structures 325 are bonded with thin film solder 327 back-to-back
and form a symmetric silicon carrier sandwich 314 with a fluid
cavity 316. As will be seen in FIG. 5, pin fins 325 or
microchannels 5999 permit passage of cooling fluid, as best seen in
the top plan view of that figure.
[0020] The thin film solder pattern forms an insulation ring 401
(i.e., in one sense, fluid integrity insulation not electrical
insulation; note, however, the ring prevents the fluid from
reaching the pad, thus providing fluid sealing to prevent
electrical shorts) to seal the electrical interconnect (the
electrical bonding pad 403) off from the coolant, as best seen in
FIG. 4. This allows the use of water as the heat transport fluid.
The pitch range of the through silicon vias (TSV) (which form the
pin fins 325) is, for example, 100 to 200 microns with a TSV height
of, for example, 75 to 150 microns per side. The total cavity
height can be, for example, 100 to 200 microns. Note that in one or
more embodiments the TSV height must exceed the cavity height to
have enough residual silicon thickness to form the cavity capable
to support the fluid pressure. The symmetric configuration of the
silicon carrier sandwich 314 results in minimal warp and increases
yield during ball grid array bonding.
[0021] A silicon or metal back-side cold plate 302 is attached to
the chip stack 308 (a four-tier stack is shown for illustrative
purposes) using a thermal interface material (TIM) 306. The
integrated manifold 304 delivers fluid to the front and back-side
heat removal cavities. To reduce mechanical stress from thermal
mismatch in case of a metal cold plate, an elastic polymer gasket
310 is used. The front-side fluid inlet and outlet are spatially
separated from the micro-C4 array of solder balls 387 to prevent
moisture diffusion through the underfill epoxy 312 causing
electro-corrosion. This double face cold plate concept nearly
doubles the heat removal from a vertical integrated chip stack.
Note that array 387 may have, for example, a 30-100 micron
pitch.
[0022] Note C4 array 389 which is used to attach the above
structure to laminate 391, 3999 (array 389 may have, for example, a
150-200 micron pitch). The laminate 391, 3999 could be, for
example, an organic build-up substrate or a ceramic single or
multi-chip module. Both portion 391 and portion 3999 represent the
laminate--portion 391 is the wiring layers and portion 3999 is
additional wiring layers. In one or more embodiments, the laminate
is a multi-layer organic build-up substrate, with or without a
core. An additional underfill layer 312 is applied to protect the
C4s between the laminate 391, 3999 and the symmetric silicon
carrier sandwich 314. This may, or may not, be the same underfill
material 312 as is used between the symmetric silicon carrier
sandwich 314 and the chip stack 308. Note that redistribution
wiring layer or layer(s) 397 is provided on the surface of the
silicon carrier sandwich which is adjacent to the vertical chip
stack 308 to transform between the larger pitch electrical
connections on the bottom (laminate side) of the silicon carrier
sandwich to the smaller pitch electrical connections on the top
(vertical chip stack side) of the silicon carrier sandwich.
[0023] FIG. 5 shows exemplary fluid cavity structures compatible
with TSV. These include two different arrangements of circular pin
fins as shown at 506, 508, as well as drop-shaped pin fins as shown
at 510. Other types of structures include conventional plate fins
5997 forming micro-channels 5999, as at 504, and "connected" pin
fins forming roughened micro-channels as at 512. An open chamber
with no fins could also be used (at least in part), as at 502; this
would result in lower pressure drop of the cooling fluid at the
expense of reduced heat transfer and 10-number. Furthermore the
mechanical integrity has to be carefully considered in this case
due to reduced number of mechanical stiffening pins.
[0024] FIG. 6 shows a cross-section through another exemplary
double-face cooled package, similar to that in FIG. 3, but with
embedded optical communication. Elements similar to those in FIGS.
3 and 4 have received the same reference character and will not be
described again. Embedded optical technologies such as on-package
silicon-photonics and embedded optical off-package communication
are sensitive to elevated temperatures and their variations.
Double-face cooling decreases absolute temperatures and temperature
variations and gradients in the chip-stack significantly.
Furthermore, the silicon carrier can serve as a thermal ground
plane for a vertical-cavity surface-emitting laser (VCSEL) 693 with
embedded wave guide 691.
[0025] It should be noted that the skilled artisan will be familiar
with the formation of through-wafer vias, and given the teachings
herein, will be able to use through-wafer via technology to make
one or more embodiments of the invention. Nevertheless, out of an
abundance of caution, the complete disclosure of co-assigned U.S.
Patent Publication 2008-0274583 of Andry et al., entitled
"Through-Wafer Vias," published on Nov. 6, 2008, is expressly
incorporated herein by reference in its entirety for all purposes;
the complete disclosure of co-assigned U.S. Patent Publication
2005-0121768 of Edelstein et al., entitled "Silicon chip carrier
with conductive through-vias and method for fabricating same,"
published on Jun. 9, 2005, is expressly incorporated herein by
reference in its entirety for all purposes; and the complete
disclosure of co-assigned U.S. Pat. No. 7,488,680 of Andry et al.,
entitled "Conductive Through Via Process for Electronic Device
Carriers," issued Feb. 10, 2009, is also expressly incorporated
herein by reference in its entirety for all purposes.
[0026] One or more embodiments of the invention advantageously
allow use of water as the cooling fluid, since there is no contact
between the cooling fluid and electrical inputs and outputs; thus,
the embodiments are not limited to dielectric cooling. The water
may be supplied by a pump 3003 and routed to an external heat
exchanger 3001 to reject the heat gained in passing through the
silicon fluid cavity and micro-channel cold plate.
[0027] One or more embodiments of the invention advantageously
allow use of solid TSVs which conduct heat from the chip stack;
these TSVs function as pin-fins within the fluid cavity 316 and do
not themselves need to serve as pipes for the cooling fluid.
[0028] The chip stack can be fabricated using a variety of known
techniques. In at least some instances, no fluid-carrying structure
needs to be interposed between the adjacent chips. Furthermore,
another advantage of one or more embodiments is reduced bowing due
to the silicon carrier sandwich.
[0029] A wide variety of alternatives are possible. FIGS. 7-10 show
cross-sectional views of various alternative embodiments. Like
elements have received the same reference characters. FIG. 7 shows
double-faced heat removal with single-sided input/output, similar
to FIGS. 3 and 6. FIG. 8 shows double-faced heat removal with
double-sided input/output. Here, the back-side cold plate is itself
a (silicon, e.g.) carrier sandwich.
[0030] FIG. 9 shows single-faced heat removal with double-sided
input/output; there is no back side cold plate and a separate inlet
and outlet manifold may be employed, for example. On the back side
note elements 989 similar to elements 389, vias 9888, and laminate
991, 9999 which could be similar, for example, to laminate 391,
3999 as described above. Other elements can be constructed and
arranged in a manner analogous to that described for the other
figures.
[0031] FIG. 10 shows double-faced heat removal with double-sided
input/output. Here, the back-side cold plate is again itself a
(silicon, e.g.) carrier sandwich.
[0032] Given the discussion thus far, it will be appreciated that,
in general terms, an exemplary apparatus, according to an aspect of
the invention, includes a plurality of heat-dissipating electronic
chips arranged in a vertical chip stack 308. The electronic chips
have electronic components thereon. A cold plate 302 is secured to
a back side of the chip stack 308. Cold plate 302 may be a metal or
silicon cold plate, for example, and in some instances may itself
be realized as a (silicon) carrier sandwich. A silicon carrier
sandwich 314 defines a fluid cavity 316 and is secured to a front
side of the chip stack 308. An inlet manifold (e.g., left hand side
of manifold 304) is configured to supply cooling fluid to the cold
plate 302 and the fluid cavity 316 of the silicon carrier sandwich
314. An outlet manifold (e.g., right hand side of manifold 304) is
configured to receive the cooling fluid from the cold plate 302 and
the fluid cavity 316 of the silicon carrier sandwich 314. The cold
plate 302, the silicon carrier sandwich 314, the inlet manifold,
and the outlet manifold (e.g., integrated manifold 304) are
configured and dimensioned to electrically isolate the cooling
fluid from the electronic components (for example, as seen in FIG.
4).
[0033] Preferably, the silicon carrier sandwich 314 includes upper
and lower halves 324 bonded together (e.g., with solder 327). In
some instances, the silicon carrier sandwich further includes a
plurality of pin fins within the fluid cavity 316, these pin fins
325 may optionally include through-silicon vias. The pin fins are
configured to conduct heat from the chip stack 308 into the cooling
fluid (see arrows 322). As seen in FIG. 5, the pin fins may have a
circular cross section, as at 506, 508; or the pin fins may have a
drop-shaped cross section, as at 510. As seen at 508, the pin fins
can be arranged in uniform columns; in other cases, as seen at 506,
the pin fins can be arranged in staggered columns. By way of
example and not limitation, the pin fins may have a pitch of from
about 100 to 200 microns and a height of from about 100 to 200
microns.
[0034] In other instances, the silicon carrier sandwich 314 further
includes a plurality of plate fins within the fluid cavity,
configured to conduct heat from the chip stack into the cooling
fluid, as seen at 504 and 512.
[0035] As noted, pump 3003 may be provided to pump the cooling
fluid, and an external heat exchanger 3001 may be coupled to the
pump, the inlet manifold, and the outlet manifold, to cool the
cooling fluid via heat transfer to an external sink (e.g., ambient
air, another liquid, and the like).
[0036] In some instances, at least one laminate structure 391, 3999
is secured to the silicon carrier sandwich 314. The laminate
structure 391 further may be a first level package substrate which
is subsequently attached to a larger circuit board using a BGA or
LGA array. As discussed below, this may be carried out by securing
element 391 to sandwich 314 with C4 array 389, sandwich 314 in turn
being secured to front side of stack 308 with micro C4 solder balls
387. In some cases, at least one optical component is embedded in
the laminate structure (see, e.g., discussion of vertical-cavity
surface-emitting laser (VCSEL) 693 with embedded wave guide
691).
[0037] Furthermore, given the discussion thus far, it will be
appreciated that, in general terms, an exemplary method of
manufacturing an electronic apparatus, according to another aspect
of the invention, includes providing a plurality of
heat-dissipating electronic chips arranged in a vertical chip stack
308. The electronic chips have electronic components thereon. An
additional step includes securing a cold plate 302 to a back side
of the chip stack 308. A further step includes securing a silicon
carrier sandwich 314, defining a fluid cavity 316, to a front side
of the chip stack 308.
[0038] Additional steps include assembling an inlet manifold (e.g.,
left hand side of 304) to the cold plate 302 and the silicon
carrier sandwich 314 in fluid communication with the cold plate and
the fluid cavity 316 of the silicon carrier sandwich; and
assembling an outlet manifold (e.g., right hand side of 304) to the
cold plate and the silicon carrier sandwich in fluid communication
with the cold plate and the fluid cavity of the silicon carrier
sandwich. It will be appreciated that when a unitary manifold 304
is employed, these two assembling steps are normally carried out
simultaneously.
[0039] A further step can include bonding upper and lower halves
324 of the silicon carrier sandwich together to form the silicon
carrier sandwich (e.g., with solder, or other conductive joining
material, 327). A still further step can include forming a
plurality of through-silicon vias as pin fins 325 within the fluid
cavity 316, configured to conduct heat from the chip stack 308 into
cooling fluid, as per arrows 322. Any of the configurations and
dimensions of pin fins described can be used, for example. In other
cases, an additional step includes forming a plurality of plate
fins (see, e.g., 504, 512) within the fluid cavity 316, configured
to conduct heat from the chip stack into cooling fluid.
[0040] In some instances, an additional step includes securing at
least one laminate structure 391, 3999 to the silicon carrier
sandwich 314. As shown in the non-limiting example in the figures,
this may be carried out by securing element 391 to sandwich 314
with C4 array 389, sandwich 314 in turn being secured to front side
of stack 308 with micro-C4 solder balls 387. As best seen in FIG.
6, an additional step can include embedding at least one optical
component in the silicon carrier sandwich.
[0041] Yet further, given the discussion thus far, it will be
appreciated that, in general terms, an exemplary method of
operating an electronic apparatus, according to another aspect of
the invention, includes providing an apparatus of the kind
described, providing chilled cooling fluid to the inlet manifold;
and exhausting heated cooling fluid from the outlet manifold.
[0042] In still another aspect, and with reference again to FIG. 9,
an exemplary apparatus includes a plurality of heat-dissipating
electronic chips arranged in a vertical chip stack 308. The
electronic chips have electronic components thereon. Also included
is a silicon carrier sandwich 314, defining a fluid cavity 316,
secured to a front side of the chip stack 308. In an inlet manifold
(left side of 304) is configured to supply cooling fluid to the
fluid cavity of the silicon carrier sandwich, and an outlet
manifold (right side of 304) is configured to receive the cooling
fluid from the fluid cavity of the silicon carrier sandwich. A
first series of electrical interconnects 389 are on a side of the
silicon carrier sandwich 314 opposite the chip stack 308. A second
series of electrical interconnects 989 are on a back side of the
chip stack 308. The silicon carrier sandwich 308, the inlet
manifold (304 left side), and the outlet manifold (304 right side)
are configured and dimensioned to electrically isolate the cooling
fluid from the electronic components. In some embodiments, the
silicon carrier sandwich 308 comprises upper and lower halves
bonded together, as in FIG. 4 and a plurality of fins within the
fluid cavity, configured to conduct heat from the chip stack into
the cooling fluid. Any of the different kinds of fins described
herein can be employed.
[0043] In yet another aspect, with reference again to FIG. 10,
double-sided heat removal with double-sided electrical input-output
is also possible. Here, said silicon carrier sandwich 314 is first
silicon carrier sandwich and said cold plate 302 is a second
silicon carrier sandwich. A first series of electrical
interconnects 389 are on a side of said first silicon carrier
sandwich opposite said chip stack. A second series of electrical
interconnects 1089 are on a side of said second silicon carrier
sandwich opposite said chip stack.
[0044] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0045] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
invention has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
invention in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the invention. The
embodiment was chosen and described in order to best explain the
principles of the invention and the practical application, and to
enable others of ordinary skill in the art to understand the
invention for various embodiments with various modifications as are
suited to the particular use contemplated.
* * * * *