U.S. patent application number 12/667469 was filed with the patent office on 2011-01-20 for heat transfer device.
Invention is credited to Pei Fan Florence Ng, Kim Tiow Ooi, Tiew Toon Phay, Yong Liang Teh.
Application Number | 20110011564 12/667469 |
Document ID | / |
Family ID | 40228853 |
Filed Date | 2011-01-20 |
United States Patent
Application |
20110011564 |
Kind Code |
A1 |
Ooi; Kim Tiow ; et
al. |
January 20, 2011 |
HEAT TRANSFER DEVICE
Abstract
A heat transfer device for maintaining a temperature of a device
under test with heat generating capability at a prescribed
temperature, the heat transfer device comprising an inlet
flow-duct; an outlet flow-duct; a conductor block comprising a
plurality of through-holes, the through-holes receiving a fluid
from the inlet flow-duct and delivering the fluid to the outlet
flow-duct; and inserts disposed in the respective through-holes for
reducing a cross-sectional area of the respective through-holes to
improve heat transfer efficiency.
Inventors: |
Ooi; Kim Tiow; (Singapore,
SG) ; Teh; Yong Liang; (Singapore, SG) ; Ng;
Pei Fan Florence; (Singapore, SG) ; Phay; Tiew
Toon; (Singapore, SG) |
Correspondence
Address: |
HEDMAN & COSTIGAN, P.C.
1230 AVENUE OF THE AMERICAS, 7th floor
NEW YORK
NY
10020
US
|
Family ID: |
40228853 |
Appl. No.: |
12/667469 |
Filed: |
December 7, 2007 |
PCT Filed: |
December 7, 2007 |
PCT NO: |
PCT/SG07/00419 |
371 Date: |
December 31, 2009 |
Current U.S.
Class: |
165/104.19 |
Current CPC
Class: |
H01L 23/34 20130101;
H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L 23/46
20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
165/104.19 |
International
Class: |
F28D 15/00 20060101
F28D015/00; F28F 13/08 20060101 F28F013/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 6, 2007 |
SG |
200705052-9 |
Claims
1. A heat transfer device for maintaining a temperature of a device
under test with heat generating capability at a prescribed
temperature, the heat transfer device comprising: an inlet
flow-duct; an outlet flow-duct; a conductor block comprising a
plurality of through-holes, the through-holes receiving a fluid
from the inlet flow-duct and delivering the fluid to the outlet
flow-duct; and inserts disposed in the respective through-holes for
reducing a cross-sectional area of the respective through-holes to
improve heat transfer efficiency, wherein the inserts disposed in
the respective through-holes are arranged such that each insert is
not restricted to a fixed position with respect to a center of the
cross-sectional area of the respective through-holes.
2. The heat transfer device as claimed in claim 1, wherein the
inserts are substantially longitudinal and are disposed in the
respective through-holes such that longitudinal axes of the
respective inserts are substantially parallel to the
through-holes.
3. The heat transfer device as claimed in claim 1, wherein the
inlet and outlet flow-ducts are secured to opposite ends of the
conductor block to form a heat transfer (HT) module, wherein heat
transfer mainly occurs in the HT module.
4. The heat transfer device as claimed in claim 1, wherein the HT
module is disposed inside a housing, and the heat transfer device
further comprises a valve disposed on the housing for removing air
inside the housing and creating a partial vacuum environment around
the HT module, wherein the partial vacuum environment facilitates
suspension of the HT module in the housing, and provides heat
transfer insulation between the HT module and the housing for
preventing condensation on the housing.
5. The heat transfer device as claimed in claim 1, wherein the
conductor block is substantially T-shaped and comprises a stem
portion and a branch portion, the branch portion comprising the
plurality of through-holes and the stem portion comprising a
surface contacting the device under test.
6. The heat transfer device as claimed in claim 5, wherein the
inlet flow-duct and the outlet flow-duct are secured to opposite
ends of the branch portion of the conductor block for facilitating
fluid flow through the through-holes.
7. The heat transfer device as claimed in claim 5, further
comprising a heater layer disposed on a surface of the branch
portion of the conductor block opposite the surface of the stem
portion of the conductor block contacting the device under
test.
8. The heat transfer device as claimed in claim 7, wherein the
heater layer is secured to the conductor block with a heater
fixture, wherein a vacuum seal is disposed between the conductor
block and the heater fixture.
9. The heat transfer device as claimed in claim 1, further
comprising a temperature sensor disposed in the conductor block for
measuring the temperature of the device under test.
10. The heat transfer device as claimed in claim 9, further
comprising a controller coupled to the temperature sensor for
maintaining the temperature of the device under test at the
prescribed temperature.
11. The heat transfer device as claimed in claim 10, wherein the
controller maintains the temperature of the device under test at
the prescribed temperature by controlling power supply to the
heater layer and/or by controlling the fluid flow.
12. The heat transfer device as claimed in claim 1, wherein, in
operation, fluid enters the through-holes in a substantially
saturated liquid state, transitions into a substantially gaseous
state under conversion of heat from the device under test, and
exits the through-holes in the substantially gaseous state.
13. The heat transfer device as claimed in claim 4, wherein the
housing is made of high strength materials for providing structural
rigidity and withstanding high pressure spikes inside the
housing.
14. The heat transfer device as claimed in claim 4, wherein the
housing is made of materials with high thermal conductivity for
preventing localized condensation on the housing.
15. The heat transfer device as claimed in claim 1, wherein the
through-holes are aligned in a plurality of rows and columns in the
conductor block.
16. The heat transfer device as claimed in claim 1, comprising one
or more insert elements, each insert element threading through one
or more of the through-holes.
17. The heat transfer device as claimed in claim 1, wherein the
inserts are made of materials with high thermal conductivity for
enhancing effective heat transfer.
18. The heat transfer device as claimed in claim 1, wherein the
conductor block is of a single integral component made of a
material with high thermal conductivity for providing effective
heat transfer.
19. A heat transfer device for maintaining a temperature of a
device under test with heat generating capability at a prescribed
temperature, the heat transfer device comprising: an inlet
flow-duct; an outlet flow-duct; a conductor block comprising a
plurality of through-holes, the through-holes receiving a fluid
from the inlet flow-duct and delivering the fluid to the outlet
flow-duct; and wherein the conductor block, inlet and outlet
flow-ducts form a HT module and the HT module is disposed inside a
housing, and the heat transfer device further comprises a valve
disposed on the housing for removing air inside the housing and
creating a partial vacuum environment around the HT module, wherein
the partial vacuum environment facilitates suspension of the
conductor block in the housing, provides heat transfer insulation
between the HT module and the housing for preventing condensation
on the housing.
20. The heat transfer device as claimed in claim 13, wherein the
housing is made of materials with high thermal conductivity for
preventing localized condensation on the housing.
Description
FIELD OF INVENTION
[0001] The present invention relates broadly to a heat transfer
device for maintaining a temperature of a device under test with
heat generating capability at a prescribed temperature.
BACKGROUND
[0002] Typically, all high-performance electronic devices are
subjected to a 100% functional test prior to being shipped by a
manufacturer. For example, high power microprocessor devices are
typically subjected to a classification test to determine an
effective operating speed of the devices. During the classification
test, it is important to keep a temperature of a die of the
microprocessor device at a single prescribed temperature while the
power of the device is varied from about 0% to about 100% of the
power rating in a predetermined test sequence.
[0003] To maintain the die at the prescribed temperature during
testing, equipments known as thermal control units (TCUs) have been
designed. Generally, a heating process is achieved by installing a
heater in the TCU. To achieve a cooling process, the TCU is coupled
to a closed loop system whereby a cold medium is delivered through
the TCU to remove heat generated by test devices such as
microprocessors. The cold medium can either be single phase flow or
two phase flow. A single phase flow medium can remove heat by
forced convection without changing its state.
[0004] Chilled water TCU technology using the single phase flow is
commonly used in microprocessor testing. It is found that the power
densities in packaged microprocessor devices have approached levels
of about 50 W/cm.sup.2 to about 100 W/cm.sup.2. As the levels of
the microprocessor device power densities increase, it is possible
that the single phase flow technology would reach its limits in
terms of testing microprocessors at lower temperatures.
[0005] Hence, there is a need to provide a new TCU which addresses
at least one of the above-mentioned problems.
SUMMARY
[0006] In accordance with a first aspect of the present invention,
there is provided a heat transfer device for maintaining a
temperature of a device under test with heat generating capability
at a prescribed temperature, the heat transfer device comprising an
inlet flow-duct; an outlet flow-duct; a conductor block comprising
a plurality of through-holes, the through-holes receiving a fluid
from the inlet flow-duct and delivering the fluid to the outlet
flow-duct; and inserts disposed in the respective through-holes for
reducing a cross-sectional area of the respective through-holes to
improve heat transfer efficiency.
[0007] The inserts disposed in the respective through-holes may be
arranged such that each insert is not restricted to a fixed
position with respect to a center of the cross-sectional area of
the respective through-holes.
[0008] The inserts may be substantially longitudinal and may be
disposed in the respective though-holes such that longitudinal axes
of the respective inserts are substantially parallel to the
through-holes.
[0009] The inlet and outlet flow-duct may be secured to opposite
ends of the conductor block to form a heat transfer (HT) module,
wherein heat transfer mainly occurs in the HT module.
[0010] The HT module may be disposed inside a housing, and the heat
transfer device may further comprise a valve disposed on the
housing for removing air inside the housing and creating a partial
vacuum environment around the HT module, wherein the partial vacuum
environment facilitates suspension of the HT module in the housing,
provides heat transfer insulation between the HT module and the
housing for preventing condensation on the housing.
[0011] The conductor block may be substantially T-shaped and
comprises a stem portion and a branch portion, the branch portion
comprising the plurality of through-holes and the stem portion
comprising a surface contacting the device under test.
[0012] The inlet flow-duct and the outlet flow-duct may be secured
to opposite ends of the branch portion of the conductor block for
facilitating fluid flow through the through-holes.
[0013] The heat transfer device may further comprise a heater layer
disposed on a surface of the branch portion of the conductor block
opposite the surface of the stem portion of the conductor block
contacting the device under test.
[0014] The heater layer may be secured to the conductor block with
a heater fixture, wherein a vacuum seal is disposed between the
conductor block and the heater fixture.
[0015] The heat transfer device may further comprise a temperature
sensor disposed in the conductor block for measuring the
temperature of the device under test.
[0016] The heat transfer device may further comprise a controller
coupled to the temperature sensor for maintaining the temperature
of the device under test at the prescribed temperature.
[0017] The controller may maintain the temperature of the device
under test at the prescribed temperature by controlling power
supply to the heater layer and/or by controlling the fluid
flow.
[0018] In operation, fluid may enter the through-holes in a
substantially saturated liquid state, transitions into a
substantially gaseous state under conversion of heat from the
device under test, and exits the through-holes in a substantially
gaseous state.
[0019] The housing may be made of high strength materials for
providing structural rigidity and withstanding high pressure spikes
inside the housing.
[0020] The housing may be made of materials with high thermal
conductivity for preventing localized condensation on the
housing.
[0021] The through-holes may be aligned in a plurality of rows and
columns in the conductor block.
[0022] The heat transfer device may comprise one or more insert
elements, each insert element threading through two or more of the
through-holes.
[0023] The inserts may be made of materials with high thermal
conductivity for enhancing effective heat transfer.
[0024] The conductor block may be of a single integral component
made of a material with high thermal conductivity for providing
effective heat transfer.
[0025] The inlet flow-duct, outlet flow-duct and heater fixture may
be made of materials with low thermal conductivity for preventing
condensation on respective top channel sections of the inlet
flow-duct, outlet flow-duct and heater fixture.
[0026] In accordance with a second aspect of the present invention,
there is provided a heat transfer device for maintaining a
temperature of a device under test with heat generating capability
at a prescribed temperature, the heat transfer device comprising an
inlet flow-duct; an outlet flow-duct; a conductor block comprising
a plurality of through-holes, the through-holes receiving a fluid
from the inlet flow-duct and delivering the fluid to the outlet
flow-duct; and wherein the conductor block, inlet flow-duct and
outlet flow-duct form a heat transfer (HT) module and the HT module
is disposed inside a housing, and the heat transfer device further
comprises a valve disposed on the housing for removing air inside
the housing and creating a partial vacuum environment around the HT
module, wherein the partial vacuum environment facilitates
suspension of the HT module in the housing, provides heat transfer
insulation between the HT module and the housing for preventing
condensation on the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Embodiments of the invention will be better understood and
readily apparent to one of ordinary skill in the art from the
following written description, by way of example only, and in
conjunction with the drawings, in which:
[0028] FIG. 1 shows a schematic drawing of a cross-sectional view
of a heat transfer device in the form of a thermal control unit
(TCU).
[0029] FIG. 2 shows a schematic drawing of a cross-sectional view
of the heat transfer (HT) module of the TCU of FIG. 1.
[0030] FIG. 3 shows a schematic drawing of another cross-sectional
view of the heat transfer device in the form of TCU.
[0031] FIG. 4 shows a schematic drawing of a cross-sectional top
view of the HT module of the TCU of FIG. 1.
[0032] FIG. 5 shows a schematic drawing of the HT module of the TCU
of FIG. 1 placed in contact with a tested device.
DETAILED DESCRIPTION
[0033] The example embodiments described herein provide a new
thermal control unit employing a two phase flow process. A two
phase flow medium experiences a change in state from liquid to
vapour to remove heat by latent heat of vaporization.
[0034] FIG. 1 shows a schematic drawing of a cross-sectional view
of a heat transfer device in the form of a thermal control unit
(TCU) 100. The TCU 100 comprises a housing 102, which comprises a
housing base 104 and a main housing body 106 respectively. A check
valve 108 is attached to the main housing body 106.
[0035] A heat transfer (HT) module 110 is disposed in the housing
102. The main housing body 106 is placed on top of the HT module
110 and the housing base 104 is placed below the HT module 110. A
portion of the HT module 110 protrudes the housing base 104. A
surface 112 of the HT module 110 is exposed to the surrounding
environment of the TCU 100. The HT module 110 is designed for fast
thermal response involving fast raising and lowering of
temperatures and maintaining at a single set temperature during
device testing. Therefore, it is important that the HT module 110
is properly insulated. The design of the HT module 110 takes into
consideration of an intrusion of environment heat flux. The heat
transfer between the environment and the HT module 110 can be
advantageously negated and a controlled vicinity surrounding the HT
module 110 can be advantageously achieved.
[0036] In electronic cooling, any presence of water in any form is
highly undesirable. As the TCU 100 operates in an open environment
under the existence of water vapours, condensation on the surfaces
of the TCU 100 is an issue. To prevent condensation on the housing
102 of the TCU 100, the HT module 110 is insulated. Air that is
contained inside the TCU 100 is drawn out using the check valve
108. By drawing out the air inside the TCU 100, a partial vacuum
environment is created within the interior of the TCU 100. With
partial vacuum in the TCU 100 being an excellent insulator, the
surface temperature of the housing 102 facing the surrounding
environment is kept above dew point temperature, which is a factor
of relative humidity and ambient temperature. Condensation on the
surfaces of HT module 110 can also,be advantageously prevented. In
addition, during heating processes, the partial vacuum region also
functions as an insulator to prevent any heat loss by the HT module
110.
[0037] Despite the condensation prevention method as described
above, the housing 102 of the TCU 100 may not be entirely free of
condensation. Condensation may still occur due to localized cold
regions on the housing 102 due to localized heat transfer between
the HT module 110 and the housing 102. Therefore, a high
conductivity material is used for manufacturing the housing 102 of
the TCU 100 to ensure good spreading of heat that prevents any
localized cold regions where condensation may occur. In one example
implementation, an aluminium alloy is used, but it will be
appreciated that other high-thermal conductivity materials may be
used in different implementations.
[0038] To minimize localized cold regions on the housing 102, it is
preferred that any direct contact between the HT module 110 and the
housing 102 is avoided or minimized. This can be achieved in the
example embodiment by suspending the HT module 110 inside the
housing 102. Vacuum seals 116 made of insulation materials of low
thermal conductivity are used to fill the gaps 122 between the
housing 102 and the HT module 110 to reduce remaining heat transfer
between the HT module 110 and the housing 102, thus achieving
minimization of localized cold regions effects. The vacuum seals
116 advantageously prevent any possible air flow from the
surrounding environment into the TCU 100. The partial vacuum region
in the TCU 100 also advantageously provides a suction effect to
hold the vacuum seals 116 in place. Due to the partial vacuum
region above the HT module 110, the pressure difference vertically
across the HT module 110 can cause the HT module 110 to be lifted
within the housing 102 under the atmospheric pressure acting on the
external surface 112 of the HT module 110, thus suspending the HT
module 110 inside the housing 102. Hard stoppers 114 made of
insulation material are clamped between the HT module 110 and the
main housing body 106 to reduce heat transfer thus minimizing
localized cold areas and to align the HT module 110 to the housing
102. In example implementations, low-thermal conductivity metals
such as stainless steel or high strength plastic such as
polycarbonate are used for the hard stoppers 114, but it will be
appreciated that other low-thermal conductivity materials may be
used in different implementations.
[0039] To ensure an airtight environment within TCU 100, the
housing 102 is properly sealed in the example embodiment. Vacuum
seals 120 are inserted between the housing base 104 and the main
housing body 106 and between the conductor block 202 and the heater
fixture 210 to prevent air leaks into the TCU 100. In the event
where faulty equipment along the process line causes a high
pressurised fluid flow into the HT module 110, the housing 102 is
designed to act as reinforcement to the HT module 110. To withstand
the pressure spikes during operation, the housing 102 is
manufactured with a high strength material that provides structural
rigidity. In one example implementation, an aluminium alloy is
used, but it will be appreciated that other high strength materials
may be used in different implementations.
[0040] FIG. 2 shows a schematic drawing of a cross-sectional view
of the HT module 110 of the TCU 100 in FIG. 1. The HT module 110
comprises a conductor block 202, an inlet flow-duct 205 and an
outlet flow-duct 206, a heater in the form of a heater layer 208
and a heater fixture 210. The conductor block 202 is substantially
T-shaped with a branch portion in the form of an upper portion 203
having a larger width than a stem portion in the form of a lower
portion 204. To facilitate effective heat transfer, the conductor
block 202 is manufactured with materials which are good conductors
of heat and manufactured as a single integral component. In one
example implementation, a copper alloy is used, but it will be
appreciated that other high-thermal conductivity materials may be
used in different implementations.
[0041] To minimize heat transfer through an intrusion of
environmental heat flux and to prevent condensation at respective
top channel sections 228, 230 and 232 of the inlet flow-duct 205,
the outlet flow-duct 206 and the heater fixture 210 that are
exposed to the open space environment, the inlet flow-duct 205, the
outlet flow-duct 206 and the heater fixture 210 are manufactured
with materials which are poor conductors of heat. For example,
low-thermal conductivity metals such as stainless steel or high
strength plastic such as polycarbonate may be used.
[0042] The inlet flow-duct 205 and the outlet flow-duct 206 are
disposed at opposite ends of the upper portion 203 of the conductor
block 202. The inlet flow-duct 205 and the outlet flow-duct 206 are
secured to the upper portion 203 of the conductor block 202 using
respective fasteners 212 on the inlet flow-duct 205 and the outlet
flow-duct 206. The upper portion 203 of the conductor block 202 is
enclosed by the inlet flow-duct 205 and the outlet flow-duct 206.
As appreciated by a person skilled in the art, the problem of
condensation as mentioned above does not occur on the conductor
block 202, the inlet flow-duct 205 and the outlet flow-duct 206 as
they are enclosed in the partial vacuum environment within the TCU
100.
[0043] The heater layer 208 is disposed on a surface 209 of the
upper portion 203 of the conductor block 202 opposite to the
surface 112 of the lower portion 204 of the conductor block 202.
The heater layer 208 is secured to the upper portion 203 of the
conductor block 202 by the heater fixture 210 using fasteners 214
and vacuum seal 120. In the example embodiment, the heater layer
208 is a commercially available flat-type resistance heater, but it
will be appreciated that other heater layer designs may be used in
different implementations. The vacuum seal 120 is disposed between
the conductor block 202 and the heater fixture 210. The heater
fixture 210 is manufactured with materials which are good
insulators of heat to minimize heat transfer. In example
implementations, low-thermal conductivity metals such as stainless
steel or high strength plastic such as polycarbonate are used, but
it will be appreciated that other low-thermal conductivity
materials may be used in different implementations. Seals 216 are
disposed between the upper portion 203 of the conductor block 202
and the inlet flow-duct 205 and the outlet flow-duct 206 to prevent
leakage of fluid. The seals 216 are made of materials which are
tolerable under both high and low temperatures. In example
implementations, viton or silicone are used, but it will be
appreciated that other low-thermal conductivity materials may be
used in different implementations.
[0044] A temperature sensor in the form of a spring-loaded
thermocouple 218 is disposed in a cavity 220, which is
substantially in the centre of the conductor block 202. The
spring-loaded thermocouple 218 is coupled to an external controller
222. The spring-loaded thermocouple 218 measures temperatures of a
device under test 502 and feedbacks the temperature measurements to
the controller 222. The controller 222 also monitors and controls
fluid flow through the HT module 110, in particular the pressure,
temperature and flow rate, and also controls a power supply to the
heater 208 layer for maintaining the temperature of the device
under test 502 at a prescribed temperature. The controller 222 is
coupled to a power supply/controller 224 and a reservoir/controller
226. The power supply/controller 224 for controlling the power
supply to the heater layer 208 is coupled to the heater layer 208.
The reservoir/controller 226 for facilitating the fluid flow is
coupled to the inlet flow-duct 205 and the outlet flow-duct
206.
[0045] FIG. 3 shows a schematic drawing of another cross-sectional
view of the heat transfer device in the form of TCU 100. As shown
in FIG. 3, the conductor block 202 of the HT module 110 comprises a
plurality of through-holes in the form of channels 302 on the upper
portion 203 of the conductor block 202. The channels 302 are
aligned in a plurality of rows and columns at two sides of the
thermocouple 218 disposed in the cavity 220 of the conductor block
202.
[0046] Two factors affecting the performance of heat transfer at
the conductor block 202 of the TCU 100 are effective heat transfer
to fluid through the conductor block 202 and the amount of fluid
delivered through the channels 302 of the conductor block 202. Flow
boiling in channels offers very high heat transfer capabilities. To
increase heat transfer coefficient of fluid flow, it is preferred
that the channels 302 have a smaller D.sub.h, where D.sub.h is the
hydraulic diameter. However, a smaller D.sub.h poses a problem in
manufacturing the conductor block 202 with the channels 302 through
conventional machining.
[0047] A longitudinal insert e.g. a wire 304 is inserted into the
channels 302 of the conductor block 202 to obstruct a portion of
flow area in every channel 302 to reduce a cross-sectional area of
the channels 302. Consequently, a smaller D.sub.h is attained. As
such, the total heat transfer coefficient of the fluid going
through the channels 302 increases, which advantageously provides a
more effective heat removal by the fluid. Given the flexibility to
control the hydraulic diameter D.sub.h of the channels 302 by using
e.g. wires 304, an increase in the diameter of the channels 302 is
advantageously provided which results in an ease of manufacturing
the conductor block 202. Therefore, conventional machining can be
used to manufacture the conductor block 202 of the TCU 100, without
forsaking the basic functions of allowing effective heat removal
and maintaining a prescribed temperature during testing. The
inserts, e.g. wires 304, disposed in the respective channels 302
are arranged such that each insert is not restricted to a fixed
position with respect to a center of the cross-sectional area of
the respective channels 302. To further enhance the effectiveness
of heat transfer, the inserts, e.g. wires 304, are made of a high
thermal conductivity material. In example implementations, the
inserts e.g. wires 304 may be provided as copper or aluminium alloy
wires, but it will be appreciated that other high-thermal
conductivity materials may be used in different
implementations.
[0048] The diameter of the through-holes and the wires are
preferred to be within the range of 0.2 mm to 3 mm. As will be
appreciated by a person skilled in the art, within 0.2-3 mm, the
flow channel is typically referred to as a mini-channel, which is
currently most suitable for the technique of the example embodiment
of using inserts to substantially reduce the cross-sectional area.
In TCU 100, the diametral ratio of the wire to the through-holes is
preferred to be within the range of more than 0.7, leading to a
reduction in cross-sectional area of more than 50 percent and in
hydraulic diameter of more than 70 percent. For the same pressure
gradient applied, the consequential reduction in flow rate is more
than 85 percent.
[0049] FIG. 4 shows a schematic drawing of a cross-sectional top
view of the HT module 110 of the TCU 100 of FIG. 1. One end of the
insert e.g. wire 304 is inserted into one end of a channel 302, is
pulled out from an opposite end of the same channel 302 and is
inserted to an adjacent end of an adjacent channel 302 in a same
row. As shown in FIG. 4, for each row of the channels 302 at each
side of the thermocouple 218 (FIG. 3) disposed in the cavity 220
(FIG. 3) of the conductor block 202, the threading of the insert
e.g. wire 304 begins at a starting point 402, which is furthest
away from the thermocouple 218 (FIG. 3) and ends at an ending point
404, which is adjacent to the thermocouple 218 (FIG. 3). It will be
appreciated by the person skilled in the art that the threading
method and/or pattern are not limited to that as described in this
embodiment. Both ends of the insert e.g. wire 304 are fixed at the
starting point 402 and the ending point 404 by e.g. welding. The
channels 302 and the insert e.g. wire 304 are enclosed by the inlet
flow-duct 205 and the outlet flow-duct 206.
[0050] FIG. 5 shows a schematic drawing of the HT module 110 of the
TCU 100 in FIG. 1 placed in contact with a device under test 502.
The device under test 502 is mounted on a mounting stage 504. By
either moving the device under test 502 upwards or moving the HT
module 110 downwards, the device under test 502 is brought into
contact with the surface 112 of the conductor block 202 for
testing. A positive contact between the device under test 502 and
the surface 112 of the conductor block 202 is achieved by means of
actuators (not shown). The connections between the device under
test 502 and the exposed surface 112 during testing are not
shown.
[0051] The device under test 502 has heat generating capability. To
maintain the temperature of the device under test 502 at the
prescribed temperature during a cooling process, heat that is
transferred from the device under test 502 to the conductor block
202 by conduction is removed by a cold medium fluid passing through
the channels 302 of the conductor block 202 by convection. The
fluid in a substantially saturated liquid state is delivered into
the inlet flow-duct 205 as indicated by arrow 506. The fluid flows
through the channels (302 of FIG. 3) of conductor block 202 in a
direction as indicated by arrow 508. The fluid within the channels
(302 of FIG. 3) experiences a change of state from a substantially
saturated liquid state to a substantially gaseous state during the
heat transfer process. The fluid in a substantially gaseous state
is delivered out of conductor block 202 through the outlet
flow-duct 206 as indicated by arrow 510. The heat is removed from
the conductor block 202 by the fluid flowing through the channels
of conductor block 202 by convection. In example implementations,
refrigerant gases such as R22, R404A and CO.sub.2 are used, but it
will be appreciated that fluids may be used in different
implementations.
[0052] To raise a temperature of the device under test 502 during a
heating process, the heater layer 208 is switched on to supply heat
to the device under test 502. Heat supplied is transferred from the
conductor block 202 to the device under test 502 by conduction.
[0053] The TCU 100 as described above advantageously achieves
desired test temperatures by using two phase flow process and
advantageously provides rapid heating and cooling. The TCU 100 as
described above has a simple design which advantageously provides
an ease of fabrication and assembly. All components of the TCU 100
are of simple geometry which can be manufactured without special
techniques and tools. This advantageously reduces machining costs.
The compactness of the design of the TCU 100 also makes it easy to
integrate into test handler systems.
[0054] Further, the design of the TCU 100 has encompassed a wide
range of considerations for its durability and reliability. For
example, rapid heating and cooling, which can cause fatigue in
materials affecting its overall performance, can be minimized
through a proper material selection. A structural layout of the TCU
100 is designed with safety features to ensure rigidity to
withstand any high pressure spikes. Hence, the design of the TCU
100 is advantageously reliable.
[0055] In addition, the TCU 100 is designed to be coupled with a
cooling system to achieve the desired results and to be used in
test handler systems which require applications of heating and
cooling of test devices.
[0056] It will be appreciated by a person skilled in the art that
numerous variations and/or modifications may be made to the present
invention as shown in the specific embodiments without departing
from the spirit or scope of the invention as broadly described. The
present embodiments are, therefore, to be considered in all
respects to be illustrative and not restrictive.
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