U.S. patent application number 16/871424 was filed with the patent office on 2021-11-11 for directly impinging pressure modulated spray cooling and methods of target temperature control.
The applicant listed for this patent is Intel Corporation. Invention is credited to Muhammad AHMAD, Paul DIGLIO, Ying-Feng PANG, David SHIA, Prabhakar SUBRAHMANYAM, Pooya TADAYON, Tewodros WONDIMU.
Application Number | 20210351106 16/871424 |
Document ID | / |
Family ID | 1000004858119 |
Filed Date | 2021-11-11 |
United States Patent
Application |
20210351106 |
Kind Code |
A1 |
SUBRAHMANYAM; Prabhakar ; et
al. |
November 11, 2021 |
DIRECTLY IMPINGING PRESSURE MODULATED SPRAY COOLING AND METHODS OF
TARGET TEMPERATURE CONTROL
Abstract
Embodiments disclosed herein include a thermal testing unit. In
an embodiment, the thermal testing unit comprises a nozzle frame,
and a nozzle plate within the frame. In an embodiment, the nozzle
plate comprises a plurality of orifices through a thickness of the
nozzle plate. In an embodiment, the thermal testing unit further
comprises a housing attached to the nozzle plate.
Inventors: |
SUBRAHMANYAM; Prabhakar;
(San Jose, CA) ; WONDIMU; Tewodros; (Hillsboro,
OR) ; PANG; Ying-Feng; (San Jose, CA) ; AHMAD;
Muhammad; (Fremont, CA) ; DIGLIO; Paul;
(Gaston, OR) ; SHIA; David; (Portland, OR)
; TADAYON; Pooya; (Portland, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Intel Corporation |
Santa Clara |
CA |
US |
|
|
Family ID: |
1000004858119 |
Appl. No.: |
16/871424 |
Filed: |
May 11, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01R 31/2642 20130101;
H01L 23/427 20130101; B05B 1/14 20130101 |
International
Class: |
H01L 23/427 20060101
H01L023/427; G01R 31/26 20060101 G01R031/26; B05B 1/14 20060101
B05B001/14 |
Claims
1. A thermal testing unit, comprising: a nozzle frame; a nozzle
plate within the frame, wherein the nozzle plate comprises a
plurality of orifices through a thickness of the nozzle plate; and
a housing attached to the nozzle plate.
2. The thermal testing unit of claim 1, wherein individual ones of
the plurality of orifices have a uniform diameter through the
thickness of the nozzle plate.
3. The thermal testing unit of claim 1, wherein individual ones of
the plurality of orifices have a tapered diameter, wherein a first
diameter on an upstream side of the nozzle plate is greater than a
second diameter on a downstream side of the nozzle plate.
4. The thermal testing unit of claim 1, wherein the plurality of
orifices comprises a first group of orifices and a second group of
orifices.
5. The thermal testing unit of claim 4, wherein the first group of
orifices are positioned within a first recess, and wherein the
second group of orifices are positioned within a second recess.
6. The thermal testing unit of claim 1, wherein the nozzle plate is
displaceable relative to the housing.
7. The thermal testing unit of claim 6, further comprising a lead
screw attached between the housing and the nozzle plate.
8. The thermal testing unit of claim 1, further comprising: a
sealant plate between the housing and the nozzle frame.
9. The thermal testing unit of claim 1, wherein a downstream side
of the nozzle frame comprises a first groove for securing a first
gasket against a substrate, and a second groove for securing a
second gasket against the substrate.
10. The thermal testing unit of claim 1, wherein the nozzle frame
comprises an opening that fluidically couples a downstream side of
the nozzle frame to a fluid output line in the housing.
11. The thermal testing unit of claim 1, further comprising: a
second nozzle plate within the nozzle frame, wherein the nozzle
plate is displaceable with respect to the second nozzle plate.
12. An electronic package, comprising: a package substrate; a die
attached to the package substrate; a spray chamber over the die,
wherein the spray chamber comprises: a fluid inlet; a nozzle
fluidically coupled to the fluid inlet, wherein the nozzle directs
a fluid towards a surface of the die; and a vapor exit port; and a
vacuum pump fluidically coupled to the vapor exit port.
13. The electronic package of claim 12, further comprising: a
plurality of nozzles fluidically coupled to the fluid inlet.
14. The electronic package of claim 12, wherein the spray chamber
is attached to the package substrate.
15. The electronic package of claim 12, further comprising: a
thermal interface material (TIM) over the die; and a thermal plate
over the TIM.
16. The electronic package of claim 15, wherein the spray chamber
is attached to the thermal plate.
17. The electronic package of claim 12, wherein the spray chamber
further comprises: a liquid exit port.
18. A temperature control system, comprising: a fluid reservoir for
holding a fluid; a spray chamber fluidically coupled to the fluid
reservoir; a pump between the spray chamber and the fluid
reservoir, wherein the pump provides the fluid to the spray
chamber; a vacuum pump fluidically coupled to the spray chamber,
wherein the vacuum pump controls a pressure within the spray
chamber; and a pressure regulator that controls the vacuum
pump.
19. The temperature control system of claim 18, wherein a die is
thermally coupled to the spray chamber.
20. The temperature control system of claim 19, wherein the die is
within the spray chamber.
21. The temperature control system of claim 19, further comprising
a thermal plate between the spray chamber and the die.
22. The temperature control system of claim 18, wherein the fluid
reservoir comprises: a heating element; and a cooling element.
23. An electronic system, comprising: a board; a package substrate
attached to the board; a die attached to the package substrate; a
spray chamber over the die, wherein the spray chamber comprises: a
fluid inlet; a nozzle fluidically coupled to the fluid inlet,
wherein the nozzle directs a fluid towards a surface of the die;
and a vapor exit port; and a vacuum pump fluidically coupled to the
vapor exit port.
24. The electronic system of claim 23, wherein the spray chamber is
attached to the package substrate.
25. The electronic system of claim 23, further comprising: a
thermal interface material (TIM) over the die; and a thermal plate
over the TIM.
Description
TECHNICAL FIELD
[0001] Embodiments of the present disclosure relate to
semiconductor devices, and more particularly to thermal solutions
for dies that include nozzles.
BACKGROUND
[0002] Electronic packages typically undergo stress testing in
order to validate the functionality. Stress testing may include
cycling the temperature of the one or more dies in the electronic
package. Thermal cycling may be used to accelerate failure of
semiconductor packages as part of the product reliability
validation. Peltier devices are commonly used to implement the
thermal cycling. However, Peltier devices degrade during use and
may require replacement during the testing in order to achieve the
expected performance. As such, the duration and the cost of stress
testing is increased.
[0003] Alternative thermal cycling systems have been proposed. One
such system includes a temperature chamber with an electric heater
and a refrigeration system. However, such systems do not provide
individual temperature control on each of the die under test (DUT)
since the temperature chamber heats and cools the whole chamber to
the same temperature. Additionally, the thermal response time is
low since heat transfer is largely limited to convection. Direct
contact cooling/heating is another solution. However, direct
contact solutions are limited in thermal performance due to the
thermal resistance of the thermal interface material (TIM) between
the package and the thermal solution. Additionally, direct contact
solutions typically cannot address localized hotspots. Another
system that has been used is a direct liquid micro channel (DLMC)
architecture. DLMC architectures have a uniformly impinging medium
against the surface of the package. However, DLMC is of limited use
because it cannot implement temperature cycling nor can it account
for non-uniform hotspots.
[0004] In addition to die testing applications, thermal control is
also an issue during the operation of dies. As thermal design power
(TDP) increases with process node scaling, thermal control is
becoming an increasingly problematic barrier to optimal device
operation. Some solutions for thermal management include immersion
cooling, micro-channel cooling, and vapor chamber cooling.
[0005] Immersion cooling requires complete motherboard and CPU
submersion in the working fluid. As such, the fluid must be a good
dielectric, such as fluorinerts. However, such working fluids
suffer from a low thermal conductivity/specific heat and cannot
pull as much heat compared to water. In micro-channel
architectures, micro-channels are placed on (or in) the silicon
device. The working fluid passed through the channels absorb the
heat through the channel walls. However, fluid flow rates are high
and the infrastructure to enable such cooling architectures is
complex. As such, this solution is expensive and cumbersome. Vapor
chamber cooling has a limited working window (i.e., they do not
operate below a certain power density of approximately 20
W/cm.sup.2), and the working temperature is limited by vapor
chamber design (e.g., vacuum conditions, size, wick design, etc.).
Vapor chambers also are susceptible to "dry-out" when the
temperature and/or power density exceeds the unit's capability.
This results in an immediate die over-temperature event.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1A is a schematic that illustrates the flow conditions
resulting from direct impingement of a fluid on a surface, in
accordance with an embodiment.
[0007] FIG. 1B is a graph that illustrates several of the boundary
conditions that may be modulated in order to provide a desired die
temperature in accordance with an embodiment.
[0008] FIG. 2A is a plan view illustration of a nozzle plate with a
plurality of orifices, in accordance with an embodiment.
[0009] FIG. 2B is a cross-sectional illustration of the nozzle
plate in FIG. 2A with uniform diameter orifices, in accordance with
an embodiment.
[0010] FIG. 2C is a cross-sectional illustration of the nozzle
plate in FIG. 2A with tapered orifices, in accordance with an
embodiment.
[0011] FIG. 3A is a plan view illustration of a nozzle plate with a
first array of orifices and a second array of orifices, in
accordance with an embodiment.
[0012] FIG. 3B is a cross-sectional illustration of the nozzle
plate in FIG. 3A with the orifices passing through an entire
thickness of the nozzle plate, in accordance with an
embodiment.
[0013] FIG. 3C is a cross-sectional illustration of the nozzle
plate in FIG. 3A with the orifices positioned within recesses in
the nozzle plate, in accordance with an embodiment.
[0014] FIG. 3D is a cross-sectional illustration of a pair of
adjacent nozzle plates, in accordance with an embodiment.
[0015] FIG. 4A is an exploded view illustration of a thermal
testing unit with a nozzle plate, in accordance with an
embodiment.
[0016] FIG. 4B is a sectional illustration of a thermal testing
unit with a nozzle plate, in accordance with an embodiment.
[0017] FIG. 5A is an exploded view illustration of a nozzle plate
with a lead screw for displacing the nozzle plate, in accordance
with an embodiment.
[0018] FIG. 5B is a sectional illustration of a thermal testing
unit with a displaceable nozzle plate, in accordance with an
embodiment.
[0019] FIG. 6A is a cross-sectional illustration of a die with a
vacuum modulated cooling system, in accordance with an
embodiment.
[0020] FIG. 6B is a cross-sectional illustration of a die with a
thermal plate in a vacuum modulated cooling system, in accordance
with an embodiment.
[0021] FIG. 6C is a cross-sectional illustration of a die with a
vacuum modulated cooling system with liquid exits, in accordance
with an embodiment.
[0022] FIG. 6D is a cross-sectional illustration of a die with a
vacuum modulated cooling system with a jet impingement
architecture, in accordance with an embodiment.
[0023] FIG. 6E is a plan view illustration of the die in FIG. 6D
that illustrates the spreading of fluid from the impingement point,
in accordance with an embodiment.
[0024] FIG. 7A is a schematic illustration of a vacuum modulated
cooling system, in accordance with an embodiment.
[0025] FIG. 7B is a schematic illustration of a vacuum modulated
cooling system, in accordance with an additional embodiment.
[0026] FIG. 7C is a schematic illustration of a vacuum modulated
cooling system, in accordance with an additional embodiment.
[0027] FIG. 8 is a process flow diagram of a process for
controlling the temperature of a die, in accordance with an
embodiment.
[0028] FIG. 9 is a cross-sectional illustration of an electronic
system that comprises a vacuum modulated cooling system, in
accordance with an embodiment.
[0029] FIG. 10 is a schematic of a computing device built in
accordance with an embodiment.
EMBODIMENTS OF THE PRESENT DISCLOSURE
[0030] Described herein are thermal solutions for dies that include
nozzles, in accordance with various embodiments. In the following
description, various aspects of the illustrative implementations
will be described using terms commonly employed by those skilled in
the art to convey the substance of their work to others skilled in
the art. However, it will be apparent to those skilled in the art
that the present invention may be practiced with only some of the
described aspects. For purposes of explanation, specific numbers,
materials and configurations are set forth in order to provide a
thorough understanding of the illustrative implementations.
However, it will be apparent to one skilled in the art that the
present invention may be practiced without the specific details. In
other instances, well-known features are omitted or simplified in
order not to obscure the illustrative implementations.
[0031] Various operations will be described as multiple discrete
operations, in turn, in a manner that is most helpful in
understanding the present invention, however, the order of
description should not be construed to imply that these operations
are necessarily order dependent. In particular, these operations
need not be performed in the order of presentation.
[0032] As noted above, current die testing thermal control systems
are not able to provide consistent temperature control.
Particularly, the use of Peltier devices is limited due to their
degradation during testing. Accordingly, embodiments disclosed
herein utilize a direct jet impingement thermal solution.
Embodiments include an architecture that allows for thermal cycling
with a jet impingement solution by having controllable knobs. For
example, the temperature of the die may be modulated by changing
one or more of: (1) a distance between the nozzle exits and the
die; (2) a fluid velocity out of the nozzle; and (3) a temperature
of the impinging fluid. These three parameters may be changed on
the fly without the need to replace hardware. Additionally, the
number of nozzles and/or the shape of the nozzles may be changed
(by replacement of the nozzle plate) in order to provide different
temperature ranges. The replacement of the nozzle plate may be
implemented manually, or by a robotic system for handling various
nozzle plates.
[0033] The direct jet impingement solution described herein is also
more flexible than existing solutions. For example, the layout of
the nozzles may be chosen to selectively remove heat from hot-spot
areas on the die. Additionally, multi-die architectures are also
easily accommodated. In some embodiments, separate nozzle plates
are used for different dies. As such, the temperature cycling of
individual dies in a system can be independently controlled.
[0034] Referring now to FIG. 1A, a schematic of the fluid flow in a
direct impingement system 100 is shown, in accordance with an
embodiment. The direct impingement system 100 comprises a nozzle
106 and an impingement surface 101. The nozzle 106 may have an
opening with a dimension D. The nozzle 106 is spaced away from the
impingement surface 101 by a distance Z. In embodiments disclosed
herein, the distance Z may be modulated to provide temperature
control of the impingement surface 101. Particularly, as Z is
decreased, the heat dissipation of the impingement surface 101 is
increased, which result in a temperature drop of the impingement
surface 101. Decreases in Z will bring the potential core 102
(which is within the free jet region 105) closer to the impingement
surface 101. The distance Z may be reduced up to the height of the
potential core 102 in some embodiments. As the distance Z is
reduced the impingement zone 103 (where the most heat transfer
occurs) grows. Outside of the impingement zone 103 is the wall jet
zone 104. Fluid velocities (as indicated by arrows) are also
provided for illustrative purposes.
[0035] Referring now to FIG. 1B, a graph of die temperature with
respect to the nozzle standoff distance Z/D is shown for various
flow rates (as indicated by the Reynolds number Re) of a fluid with
a given temperature. As shown, higher stand-off heights Z/D
generally result in higher die temperatures. Additionally,
increases in the flow rate will generally result in lower die
temperatures. Therefore, modulations to the standoff height Z/D and
the flow rate Re may be made to provide any desired die temperature
between approximately 80.degree. C. and 135.degree. C. It is to be
appreciated that standoff heights Z/D and flow rates Re are not
limited to the data points shown, and the obtainable temperature
range of the die temperature may extend beyond 80.degree. C. and
135.degree. C.
[0036] Additionally, FIG. 1B depicts the data points for a working
fluid at one temperature. It is to be appreciated that reducing or
increasing the temperature of the working fluid will result in
different die temperature ranges. For example, at a high flow rate
Re (e.g., 20,000) and a working fluid temperature at approximately
-70.degree. C., a die temperature of less than 0.degree. C. may be
obtained. Accordingly, by modulating one or more of standoff height
Z/D, flow rate Re, and working fluid temperature, a die temperature
range from approximately -40.degree. C. to 135.degree. C. (or
greater) may be obtained. In some embodiments, a reservoir of
working fluid may be temperature controlled (e.g., with a heater
and/or a chiller). In some embodiments a pair of reservoirs of
working fluid may be used. For example, a first reservoir may be
maintained at a first temperature and the second reservoir may be
maintained at a second temperature that is lower than the first
temperature. As such, temperature cycling between the first
temperature and the second temperature can be rapidly
implemented.
[0037] Furthermore, the graph in FIG. 1B illustrates temperature
ranges for a package with a high power density (e.g., approximately
10 W/mm.sup.2). It is to be appreciated that at lower power
densities, the die temperature range may be expanded, For example,
an obtainable die temperature may be less than approximately
-40.degree. C. or greater than approximately 135.degree. C.
[0038] Also, in an embodiment comprising a multi-chip package
(MCP), with two different chips dissipating two different power
scenarios, a dual chamber of nozzles may be implemented. For the
higher power dissipating chip, a coolant fluid such as water with
higher thermal conductivity is allowed to be impinged on the die as
the working fluid. For the lower power dissipating chip, such as a
PCH chip for instance, it is desirable to have a lower conductivity
fluids such as air as the impinging fluid. This dual chamber nozzle
design is illustrated in FIG. 5A. Accordingly, embodiments
disclosed herein are able to dispense two different fluids
simultaneously, as necessary, to dissipate heat from multi-chip
packages involving multiple dies.
[0039] Referring now to FIG. 2A, a plan view illustration of a
nozzle plate 210 is shown, in accordance with an embodiment. The
nozzle plate 210 may comprise an array of orifices 212 that pass
through the nozzle plate 210. The array of orifices 212 may have
any pattern. In FIG. 2A, the orifices 212 are shown in a
substantially regular grid. However, it is to be appreciated that
the orifices 212 may be positioned in an irregular pattern. For
example, the orifices 212 may be positioned so they align with
hotspots of a die (not shown). In the illustrated embodiment,
twenty four orifices 212 are shown. However, it is to be
appreciated that any number of orifices 212 may be included on the
nozzle plate 210. Changing the number of orifices 212 in the nozzle
plate 210 may be one of several boundary conditions that may be
modulated to provide a desired die temperature. In an embodiment,
the nozzle plate 210 may comprise any suitable material. In some
embodiments, the nozzle plate 210 may comprise a metallic material
(e.g., stainless steel). In other embodiments, the nozzle plate 210
may comprise a polymeric material.
[0040] Referring now to FIGS. 2B and 2C, cross-sectional
illustrations of the nozzle plate 210 in FIG. 2A along line Z-Z'
are shown, in accordance with different embodiments. As shown in
FIG. 2B, the orifices 212 have a constant diameter D. A constant
diameter D results in an substantially constant fluid flow rate
through the nozzle plate 210. In an embodiment, the diameter D may
be between approximately 0.125 mm and approximately 1.0 mm. As
shown in FIG. 2C, the orifices 212 have first diameter D.sub.1 at
an upstream side of the nozzle plate 210 and a second diameter
D.sub.2 at a downstream side of the nozzle plate 210. In a
particular embodiment, the second diameter D.sub.2 is smaller than
the first diameter D.sub.1. For example, the first diameter D.sub.1
may be approximately 0.50 mm and the second diameter D.sub.2 may be
approximately 0.125 mm. Such an orifice may be referred to as a
tapered orifice herein. Reducing the second diameter D.sub.2
results in an increase in the flow rate through a thickness of the
nozzle plate 210. Changing the shape of orifices 212 in the nozzle
plate 210 may be one of several boundary conditions that may be
modulated to provide a desired die temperature.
[0041] Referring now to FIG. 3A, a plan view illustration of a
nozzle plate 310 for use in controlling temperature in a multi-die
package is shown, in accordance with an additional embodiment. The
nozzle plate 310 comprises a first array 314.sub.A of orifices 312
and a second array 314.sub.B of orifices 312. The first array
314.sub.A of orifices 312 may be used to provide thermal control of
a first die (not shown) and the second array 314.sub.B of orifices
312 may be used to provide thermal control of a second die (not
shown). As shown, the first array 314.sub.A and the second array
314.sub.B are substantially similar. However, it is to be
appreciated that the layout of the orifices 312 in each array 314
and/or a number of orifices 312 in each array 314 may be
non-uniform in order to account for differences between the first
die and the second die. For example, the two dies may have
different footprints and/or different hotspot locations.
[0042] Referring now to FIGS. 3B and 3C, cross-sectional
illustrations along lines 3-3' of FIG. 3A are shown, in accordance
with various embodiments. As shown in FIG. 3B, the orifices 312
pass entirely through a thickness of the nozzle plate 310 from an
upstream surface 311 to a downstream surface 315. While tapered
orifices 312 are shown, it is to be appreciated that constant
diameter orifices 312 may also be provided. As shown in FIG. 3C,
the orifices 312 are positioned in recesses in the nozzle plate
310. That is, the orifices 312 pass through the nozzle plate 310
from a recessed surface 313 to the downstream surface 315.
[0043] Referring now to FIG. 3D, a plan view illustration of a pair
of nozzle plates 310.sub.A and 310.sub.B are shown, in accordance
with an embodiment. The first nozzle plate 310.sub.A may comprise a
first array 314.sub.A of orifices 312, and the second nozzle plate
310.sub.B may comprise a second array 314.sub.B of orifices 312.
The use of discrete nozzle plates 310.sub.A and 310.sub.B allow for
independent control of the temperature of different dies within an
electronic package. For example, the use of discrete nozzle plates
310 allows for the first nozzle plate 310.sub.A to have a first
standoff distance Z.sub.1 and the second nozzle plate 310.sub.B to
have a second standoff distance Z.sub.2 that is different than the
first standoff distance Z.sub.1.
[0044] Referring now to FIG. 4A, an exploded view illustration of a
thermal testing unit 420 is shown, in accordance with an
embodiment. The thermal testing unit 420 may comprise a housing
421, a nozzle frame 423, and a nozzle plate 410 within the nozzle
frame 423. In an embodiment, the nozzle plate 410 may be similar to
any of the nozzle plate embodiments described above with respect to
FIGS. 2A-3D. In an embodiment, a seal plate 422 (e.g., an O-ring
sealant plate) may separate the housing 421 from the nozzle frame
423. One or more gaskets 424 and 425 may be positioned between the
nozzle frame 423 and a package substrate 426. One or more dies 427
may be positioned within an innermost gasket 425. The dies 427 may
be lidded or bare dies.
[0045] Referring now to FIG. 4B, a sectional illustration of a
thermal testing unit 420 is shown, in accordance with an
embodiment. As shown, the housing 421 comprises a fluid inlet pipe
428 that feeds a port 429. The port 429 is fluidically coupled to
the nozzle plate 410. Fluid may pass through the orifices 412 of
the nozzle plate 410 and impinge the underlying dies 427. The fluid
may then pass through exit holes 419 between the nozzle plate 410
and the nozzle frame 423 to reach an exit port 418 in the housing
421. The one or more gaskets 424 and 425 may confine the fluid to
the region surrounding the die 427. In an embodiment, the fluid for
the thermal testing unit 420 may be water. Other embodiments may
include other fluids, such as fluorinerts. Additionally, the fluid
may also be a gas, such as air, helium, etc.
[0046] Referring now to FIG. 5A, an exploded view illustration of a
nozzle plate 510 with an actuation mechanism 532 is shown, in
accordance with an embodiment. The actuation mechanism 532 provides
displacement in the vertical (Z) direction and allows for the
standoff height Z between the orifices 512 and a die (not shown) to
be changed. As described above, changes to the standoff height Z
allow for modulation of the temperature of the die. In the
illustrated embodiment, the actuation mechanism 532 is a screw,
such as a lead screw. The screw of the actuation mechanism 532 may
insert into a threaded hole 531. Bushings 533 and alignment pins
534 may also be included to guide the actuation mechanism. While a
lead screw is shown, it is to be appreciated that embodiments may
use any suitable actuation mechanism, (e.g., hydraulics, or any
other linear actuator).
[0047] Referring now to FIG. 5B, a sectional illustration of a
thermal testing unit 520 with an actuatable nozzle plate 510 is
shown, in accordance with an embodiment. In an embodiment, the
thermal testing unit 520 comprises a housing 521, a seal plate 522,
and a nozzle frame 523. A nozzle plate 510 is disposed within the
nozzle frame 523. In an embodiment, the nozzle plate 510 may be
substantially similar to any of the nozzle plates described herein.
Exit holes 519 may be provided between the nozzle plate 510 and the
nozzle frame 523 to remove working fluid after impingement on a die
(not shown). One or more gaskets 524 and 525 may surround the
nozzle plate 510.
[0048] In an embodiment, an actuation mechanism 532 passes through
the housing 521 and is mechanically coupled to the nozzle plate
510. For example, a lead screw is shown as the actuation mechanism
532 in FIG. 5B. In an embodiment, the lead screw is driven by a
motor 532 that is over the housing 521. The motor 532 may be
controlled by a control unit (not shown) that raises and/or lowers
the nozzle plate 510 in order to provide temperature cycling of the
die or dies (not shown).
[0049] In an embodiment, the controller may also provide modulation
of a working fluid flow rate and/or working fluid temperature.
Accordingly, the die temperature may be modulated over a larger
range by controlling the various boundary conditions. Additionally,
the nozzle plate 510 may be replaceable in order to accommodate
different hotspots in different dies, to provide fewer or more
orifices 512, and/or to provide a different shape of the
orifices.
[0050] In FIG. 5B, a single actuation mechanism 532 is shown.
However, it is to be appreciated that additional actuation
mechanisms 532 may be included. For example, when discrete nozzle
plates 510 are provided for each die (e.g., similar to FIG. 3D),
each nozzle plate 510 may be controlled independently with
different actuation mechanisms 532.
[0051] While the embodiments described above are particularly
useful for die testing and validation applications, embodiments
disclosed herein may also comprise thermal control systems for dies
during normal use conditions instead of (or in addition to) die
testing and validation.
[0052] As noted above the increased power demands of advanced node
dies has resulted in significant increases in TDP. Current
solutions are either not adequate to meet the heat transfer needs
for such high power outputs, and/or the solutions are complex and
expensive. Accordingly, embodiments disclosed herein include a
spray chamber that is disposed over the die. In an embodiment, the
spray chamber is a pressure controlled chamber. Changing the
pressure within the chamber allows for modulation of the boiling
point of the working fluid that is sprayed over the die within the
chamber. Particularly, reducing the boiling point allows for a
rapid phase change to remove a significant amount of thermal energy
from the die. For example, power removal has been shown in excess
of approximately 250 W/cm.sup.2, and 1,000 W total for exemplary
systems without much optimization.
[0053] Such thermal solutions also provide fast thermal control.
This is because there is little to no thermal mass of an additional
heat exchanger in the system. As such, rapid temperature control is
provided. Additionally, there is a low thermal gradient on the die
when using such systems. This because the areas of higher
temperature (i.e., hotspots) will drive a phase change of the
working fluid more rapidly. Such thermal solutions also avoid the
issue of "dry-out" that hamper the use of traditional vapor
chambers, as described above. Dry-out is avoided because the fluid
dispense volume may be directly regulated by the cooling system
controller. That is, more working fluid can be readily applied to
the die from a reservoir. Additionally, infrastructure requirements
and fluid flow-rates needed to operate embodiments disclosed herein
at large scale (e.g., servers, high performance computing (HPC),
etc.) are minimal compared to those of traditional microchannel
heat exchangers.
[0054] Furthermore, while described herein as a thermal solution
used for dies in normal operating conditions, it is to be
appreciated that similar systems may be utilized in die testing and
validation setups. For example, the temperature range is not
limited since the working fluid can be easily exchanged to better
match the targeted test set point relative to the working fluids
range of boiling points.
[0055] Referring now to FIG. 6A, a cross-sectional illustration of
an electronic package 640 is shown, in accordance with an
embodiment. The electronic package 640 may comprise a package
substrate 641 and a die 642 over the package substrate. While a
single die 642 is shown, it is to be appreciated that the
electronic package 640 may be a multi-chip package in some
embodiments. In an embodiment, a spray chamber 644 is disposed over
the die 642. A spray chamber housing may be secured against the
package substrate 641 by an attachment structure 647. The
attachment structures 647 may form a hermetic seal. The spray
chamber 644 may have an interior volume 643.
[0056] In an embodiment, a working fluid 646 may be dispensed into
the interior volume 643 through a nozzle 645 of the spray chamber
644. While two nozzles 645 are shown, it is to be appreciated that
any number of nozzles 645 (e.g., one or more) may spray the working
fluid 646 into the interior volume 643. In some embodiments, the
nozzles 645 are atomizers in order to provide a fine misting of the
working fluid 646 into the interior volume 643. The nozzles 645 may
be arranged in order to provide a uniform spray over the surface of
the die 642. The working fluid 646 may enter the nozzles through a
fluid input line 648 that is fluidically coupled to a fluid
reservoir (not shown).
[0057] In an embodiment, the interior volume 643 of the spray
chamber 644 is pressure controlled. Particularly, a vapor outlet
639 may be coupled to a vacuum pump (not shown) in order to provide
a desired pressure within the spray chamber 644. In some
embodiments, the pressure may be below atmospheric pressure.
Lowering the pressure results in a reduction of the boiling point
of the working fluid 646. As such, when the working fluid 646 is
dispensed into the interior volume 643 of the spray chamber 644, it
undergoes a rapid phase change (from liquid to gas) and provides a
large extraction of thermal energy from the die 642. In an
embodiment, the pressure of the interior volume 643 may be
controlled to be between approximately 0.05 atm and 2 atm. In order
to make the phase change even faster, the working fluid 646 may be
heated to a temperature above the boiling point in the low pressure
environment.
[0058] Since the phase change can occur directly on the die 642 (or
on a die lid), there is no additional thermal mass. As such, the
temperature control is rapid. Additionally, dry-out is avoided
since the working fluid 646 is supplied by a reservoir (which may
also recapture the fluid from the vapor line) and constantly
replenished. Furthermore, there is a low thermal gradient on the
die when using such systems. This is because the areas of higher
temperature (i.e., hotspots) will drive a phase change of the
working fluid more rapidly
[0059] Referring now to FIG. 6B, a cross-sectional illustration of
an electronic package 640 is shown, in accordance with an
additional embodiment. The electronic package 640 in FIG. 6B may be
substantially similar to the electronic package 640 in FIG. 6A,
with the exception that a thermal plate 649 is positioned between
the die 642 and the spray chamber 644. The thermal plate 649 may be
thermally coupled to the die 642 by a thermal interface material
(TIM) 651. The spray chamber 644 may be attached to the thermal
plate 649 instead of the package substrate 641. A gasket 650 may
provide a seal between the thermal plate 649 and the spray chamber
644. At the cost of a larger thermal mass, such an architecture may
allow for the die 642 and package substrate 641 to be sealed off
from the working fluid 646. Such an embodiment may be particularly
useful for die testing and validation applications.
[0060] Referring now to FIG. 6C, a cross-sectional illustration of
an electronic package 640 is shown, in accordance with an
additional embodiment. The electronic package 640 may be
substantially similar to the electronic package 640 in FIG. 6A,
with the exception of one or more additional fluid exit paths.
Particularly, an exit 638 may be provided to remove any residual
liquid from the interior volume 643. The exit 638 may be
fluidically coupled to an additional vacuum pump (i.e., a different
vacuum pump than the one fluidically coupled to the vapor exit
639). Accordingly, if the fluid 646 does not all completely
vaporize, then excess fluid will not build up in the electronic
package.
[0061] Referring now to FIG. 6D, a cross-sectional illustration of
an electronic package 640 is shown, in accordance with an
additional embodiment. As shown, the fluid 646 is impinged on the
surface of the die 642 via a jet, instead of a spray. After hitting
the surface of the die 642 a thin layer 696 spreads across the
surface of the die 642.
[0062] Referring now to FIG. 6E, a plan view illustration of a die
642 is shown. As shown, the die 642 may be impinged with a jet of
fluid at an impingement point 695. From the impingement point 695,
the fluid will spread out radially (as indicated by the arrows) via
a laminar flow that produces a thin film of fluid on the surface of
the die 642. Due to this consistent (but thin) high velocity film,
phase change can rapidly occur across the entire surface of the
die. If the fluid film is too thick (e.g., so that it pools) or is
not replenished instantly after boiling occurs (e.g., so that
dry-out occurs) the rate of phase changes is drastically reduced.
While a single impingement point 695 is shown, it is to be
appreciated that a plurality of impingement points 695 may be used
(i.e., by using multiple nozzles). In such embodiments, placement
of the nozzles should be selected in order to minimize stagnation
zones between impingement points 695. Stagnation zones will result
in areas of lower heat-flux, and should therefore be minimized or
eliminated completely.
[0063] Referring now to FIG. 7A, a schematic of a temperature
control system 760 is shown, in accordance with an embodiment. The
temperature control system 760 may be used in combination with a
spray chamber 761 to control the temperature of a die (not shown),
in accordance with an embodiment. The spray chamber 761 in FIG. 7A
may be similar to any of the electronic packages 640 described
above.
[0064] In an embodiment, a reservoir 763 is fluidically coupled to
the spray chamber 761. A pump 742 may provide a working fluid 746
from the reservoir 763 to the spray chamber 761. After the working
fluid 746 undergoes a phase change in the spray chamber 761, it is
evacuated from the spray chamber through a vacuum pump 764 that is
fluidically coupled to the spray chamber 761. The vacuum pump 764
may be controlled by a pressure regulator 765. The vacuum pump 764
sets a pressure in the spray chamber 761 that enables a rapid phase
change of the working fluid 746. After passing the vacuum pump 764,
the working fluid may be condensed and returned to the reservoir
763 for reuse.
[0065] Referring now to FIG. 7B, a schematic of a temperature
control system 760 is shown, in accordance with an additional
embodiment. The temperature control system 760 in FIG. 7B is
substantially similar to the temperature control system 760 in FIG.
7A, with the exception of the addition of several features. For
example, the temperature control system 760 may comprise heating
and cooling systems for the reservoir 763. Particularly, the
reservoir 763 may comprise a heater 766 and a cooling system, such
as a chiller 767. In some embodiments a muffler 768 may be attached
to the reservoir 763 to vent air from the reservoir 763 as well. In
some embodiments, the fluid line between the reservoir 763 and the
spray chamber 761 may also comprise an inline heater or cooler 759
in order to ensure the fluid entering the spray chamber 761 is at
the proper temperature.
[0066] Referring now to FIG. 7C, a schematic of a temperature
control system 760 is shown, in accordance with an additional
embodiment. The temperature control system 760 in FIG. 7C may be
substantially similar to the temperature control system 760 in FIG.
7B, with the addition of an extra fluid line from the spray chamber
761. Particularly, the first vacuum 764.sub.A may pull vapor from
the spray chamber 761 and set the pressure within the spray chamber
761. The first vacuum 764.sub.A may be controlled by a pressure
regulator 765 in order to modulate the pressure within the spray
chamber 761. The second vacuum 764.sub.B may pull residual liquid
from the spray chamber 761 (i.e., similar to the embodiment shown
in FIG. 6C). The second vacuum 764.sub.B may not be actively
controlled in some embodiments, or the second vacuum 764.sub.B may
be controlled similar to the first vacuum 764.sub.A. In an
embodiment, the absolute pressure from the second vacuum 764.sub.B
may be lower than that of the first vacuum 764.sub.A. For example,
the first vacuum 764.sub.A may generate an absolute pressure
between approximately 0.05 atm and approximately 2.0 atm, and the
second vacuum 764.sub.B may generate an absolute pressure between
approximately 0.05 atm and approximately 0.1 atm.
[0067] In an embodiment, the temperature control system 760 may
also comprise a fluid/air separator 769. The fluid/air separator
769 may be coupled to the muffler 768 in order to vent the air
while recapturing the fluid 746 in the reservoir 763.
[0068] In FIGS. 7A-7C it is to be appreciated that the schematics
have been simplified in order to not obscure aspects of various
embodiments. It is to be appreciated that temperature control
systems 760 may also comprise various flow control valves, pressure
gauges, temperature sensors, or fluid level sensors in order to
execute various temperature control processes, such as those
described herein.
[0069] Referring now to FIG. 8, a process flow diagram illustrating
a process 880 for temperature control of a die (i.e., a DUT) is
shown, in accordance with an embodiment. The process 880 may be
implemented using any of the temperature control systems 760
described above.
[0070] In an embodiment, process 880 begins with operation 881,
which comprises preheating a fluid to near a DUT setpoint. In an
embodiment, the temperature of the fluid may be controlled within
the reservoir and/or using an inline heater between the reservoir
and the spray chamber.
[0071] In an embodiment, process 880 continues with operation 882,
which comprises controlling a pressure in a spray chamber so that a
boiling point of the fluid is at or below the DUT setpoint. The
pressure may be reduced below atmospheric pressure using a vacuum
pump or the like that is fluidically coupled to the spray
chamber.
[0072] In an embodiment, process 880 continues with operation 883,
which comprises dispensing fluid through a nozzle into the spray
chamber. In an embodiment, the fluid is rapidly vaporized due to
the temperature of the fluid being at or above the boiling
temperature within the spray chamber. The rapid phase change allows
for heat to be efficiently removed from the DUT.
[0073] In an embodiment, process 880 continues with operation 884,
which comprises evacuating vapor from the spray chamber. The vapor
may be evacuated using a vacuum pump or the like. In some
embodiments, residual fluid may also be removed using fluid exit
lines, such as those shown in FIGS. 6C and 7C.
[0074] In an embodiment, process 880 continues with operation 885,
which comprises harvesting the fluid after evacuation from the
spray chamber. In an embodiment, the vapor is condensed to return
it to a fluid phase that can be returned to the reservoir. The
condensation may occur before reaching the reservoir or at the
reservoir.
[0075] Referring now to FIG. 9, a cross-sectional illustration of
an electronic system 990 is shown, in accordance with an
embodiment. In an embodiment, the electronic system 990 comprises a
board 991 and an electronic package substrate 940 attached to the
board by interconnects 992. The interconnects 992 are shown as
solder bumps, but any interconnect architecture (e.g., wire bonds,
sockets, etc.) may be used to connect the electronic package 940 to
the board 991.
[0076] In an embodiment, the electronic package 940 comprises a
package substrate 941 and a die 942. A spray chamber 944 may be
disposed over the die 942. The spray chamber 944 may have a fluid
inlet 948 and one or more nozzles 945 for dispensing fluid 946 over
the die 942. In an embodiment, an outlet 939 through the spray
chamber 944 is provided for removing vapor (and for controlling
pressure within an interior volume 943 of the spray chamber 944).
The spray chamber 944 may be sealed against the package substrate
with attachment structures 947.
[0077] In an embodiment, the electronic package 940 is
substantially similar to the electronic package 640 in FIG. 6A.
However, it is to be appreciated that the electronic package 940
may be substantially similar to any of the electronic packages
disclosed herein.
[0078] FIG. 10 illustrates a computing device 1000 in accordance
with one implementation of the invention. The computing device 1000
houses a board 1002. The board 1002 may include a number of
components, including but not limited to a processor 1004 and at
least one communication chip 1006. The processor 1004 is physically
and electrically coupled to the board 1002. In some implementations
the at least one communication chip 1006 is also physically and
electrically coupled to the board 1002. In further implementations,
the communication chip 1006 is part of the processor 1004.
[0079] These other components include, but are not limited to,
volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM),
flash memory, a graphics processor, a digital signal processor, a
crypto processor, a chipset, an antenna, a display, a touchscreen
display, a touchscreen controller, a battery, an audio codec, a
video codec, a power amplifier, a global positioning system (GPS)
device, a compass, an accelerometer, a gyroscope, a speaker, a
camera, and a mass storage device (such as hard disk drive, compact
disk (CD), digital versatile disk (DVD), and so forth).
[0080] The communication chip 1006 enables wireless communications
for the transfer of data to and from the computing device 1000. The
term "wireless" and its derivatives may be used to describe
circuits, devices, systems, methods, techniques, communications
channels, etc., that may communicate data through the use of
modulated electromagnetic radiation through a non-solid medium. The
term does not imply that the associated devices do not contain any
wires, although in some embodiments they might not. The
communication chip 1006 may implement any of a number of wireless
standards or protocols, including but not limited to Wi-Fi (IEEE
802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term
evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS,
CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as any
other wireless protocols that are designated as 3G, 4G, 5G, and
beyond. The computing device 1000 may include a plurality of
communication chips 1006. For instance, a first communication chip
1006 may be dedicated to shorter range wireless communications such
as Wi-Fi and Bluetooth and a second communication chip 1006 may be
dedicated to longer range wireless communications such as GPS,
EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.
[0081] The processor 1004 of the computing device 1000 includes an
integrated circuit die packaged within the processor 1004. In some
implementations of the invention, the integrated circuit die of the
processor may be thermally controlled in a spray chamber with a
modulated pressure, in accordance with embodiments described
herein. The term "processor" may refer to any device or portion of
a device that processes electronic data from registers and/or
memory to transform that electronic data into other electronic data
that may be stored in registers and/or memory.
[0082] The communication chip 1006 also includes an integrated
circuit die packaged within the communication chip 1006. In
accordance with another implementation of the invention, the
integrated circuit die of the communication chip may be thermally
controlled in a spray chamber with a modulated pressure, in
accordance with embodiments described herein.
[0083] The above description of illustrated implementations of the
invention, including what is described in the Abstract, is not
intended to be exhaustive or to limit the invention to the precise
forms disclosed. While specific implementations of, and examples
for, the invention are described herein for illustrative purposes,
various equivalent modifications are possible within the scope of
the invention, as those skilled in the relevant art will
recognize.
[0084] These modifications may be made to the invention in light of
the above detailed description. The terms used in the following
claims should not be construed to limit the invention to the
specific implementations disclosed in the specification and the
claims. Rather, the scope of the invention is to be determined
entirely by the following claims, which are to be construed in
accordance with established doctrines of claim interpretation.
[0085] Example 1: a thermal testing unit, comprising: a nozzle
frame; a nozzle plate within the frame, wherein the nozzle plate
comprises a plurality of orifices through a thickness of the nozzle
plate; and a housing attached to the nozzle plate.
[0086] Example 2: the thermal testing unit of Example 1, wherein
individual ones of the plurality of orifices have a uniform
diameter through the thickness of the nozzle plate.
[0087] Example 3: the thermal testing unit of Example 1 or Example
2, wherein individual ones of the plurality of orifices have a
tapered diameter, wherein a first diameter on an upstream side of
the nozzle plate is greater than a second diameter on a downstream
side of the nozzle plate.
[0088] Example 4: the thermal testing unit of Examples 1-3, wherein
the plurality of orifices comprises a first group of orifices and a
second group of orifices.
[0089] Example 5: the thermal testing unit of Example 4, wherein
the first group of orifices are positioned within a first recess,
and wherein the second group of orifices are positioned within a
second recess.
[0090] Example 6: the thermal testing unit of Examples 1-5, wherein
the nozzle plate is displaceable relative to the housing.
[0091] Example 7: the thermal testing unit of Example 6, further
comprising a lead screw attached between the housing and the nozzle
plate.
[0092] Example 8: the thermal testing unit of Examples 1-7, further
comprising: a sealant plate between the housing and the nozzle
frame.
[0093] Example 9: the thermal testing unit of Examples 1-8, wherein
a downstream side of the nozzle frame comprises a first groove for
securing a first gasket against a substrate, and a second groove
for securing a second gasket against the substrate.
[0094] Example 10: the thermal testing unit of Examples 1-9,
wherein the nozzle frame comprises an opening that fluidically
couples a downstream side of the nozzle frame to a fluid output
line in the housing.
[0095] Example 11: the thermal testing unit of Examples 1-10,
further comprising: a second nozzle plate within the nozzle frame,
wherein the nozzle plate is displaceable with respect to the second
nozzle plate.
[0096] Example 12: an electronic package, comprising: a package
substrate; a die attached to the package substrate; a spray chamber
over the die, wherein the spray chamber comprises: a fluid inlet; a
nozzle fluidically coupled to the fluid inlet, wherein the nozzle
directs a fluid towards a surface of the die; and a vapor exit
port; and a vacuum pump fluidically coupled to the vapor exit
port.
[0097] Example 13: the electronic package of Example 12, further
comprising: a plurality of nozzles fluidically coupled to the fluid
inlet.
[0098] Example 14: the electronic package of Example 12 or Example
13, wherein the spray chamber is attached to the package
substrate.
[0099] Example 15: the electronic package of Examples 12-14,
further comprising: a thermal interface material (TIM) over the
die; and a thermal plate over the TIM.
[0100] Example 16: the electronic package of Example 15, wherein
the spray chamber is attached to the thermal plate.
[0101] Example 17: the electronic package of Examples 12-16,
wherein the spray chamber further comprises: a liquid exit
port.
[0102] Example 18: a temperature control system, comprising: a
fluid reservoir for holding a fluid; a spray chamber fluidically
coupled to the fluid reservoir; a pump between the spray chamber
and the fluid reservoir, wherein the pump provides the fluid to the
spray chamber; a vacuum pump fluidically coupled to the spray
chamber, wherein the vacuum pump controls a pressure within the
spray chamber; and a pressure regulator that controls the vacuum
pump.
[0103] Example 19: the temperature control system of Example 18,
wherein a die is thermally coupled to the spray chamber.
[0104] Example 20: the temperature control system of Example 19,
wherein the die is within the spray chamber.
[0105] Example 21: the temperature control system of Example 19,
further comprising a thermal plate between the spray chamber and
the die.
[0106] Example 22: the temperature control system of Examples
18-21, wherein the fluid reservoir comprises: a heating element;
and a cooling element.
[0107] Example 23: an electronic system, comprising: a board; a
package substrate attached to the board; a die attached to the
package substrate; a spray chamber over the die, wherein the spray
chamber comprises: a fluid inlet; a nozzle fluidically coupled to
the fluid inlet, wherein the nozzle directs a fluid towards a
surface of the die; and a vapor exit port; and a vacuum pump
fluidically coupled to the vapor exit port.
[0108] Example 24: the electronic system of Example 23, wherein the
spray chamber is attached to the package substrate.
[0109] Example 25: the electronic system of Example 23 or Example
24, further comprising: a thermal interface material (TIM) over the
die; and a thermal plate over the TIM.
* * * * *