KR20070022232A - Miniature Fluid-Cooled Heat Sink with Integral Heater - Google Patents

Abstract

A temperature control device comprising a mini liquid-cooled heat sink with an integrated heater and sensing element is used as part of a system that provides a controlled temperature surface to electronic devices such as semiconductor devices during testing. The temperature control device includes an interface surface configured to provide a thermal path from the device to the device under test. Such a device has a liquid-cooled heat sink comprising a first heat transfer portion in a first plane and a second heat transfer portion in a second plane. The first and second heat transfer sections establish three-dimensional cross-flow of refrigerant within the heat sink structure. Another embodiment includes parallel fluid conduits, each fluid conduit having a three-dimensional microchannel structure that induces refrigerant flow three-dimensionally within the fluid conduit. Refrigerant flowing in opposite directions through adjacent fluid conduits therefore results in three-dimensional cross-sectional flow within the heat sink structure.

Fluid-Cooled, Integrated Heater, Interface Surface

Description

Miniature Fluid-Cooled Heat Sink with Integral Heater

The present invention generally relates to a temperature control device for controlling the temperature of an electronic device during testing. More particularly, the present invention relates to a mini fluid-cooled heat sink having an integrated heater and a sensing element that maintains a constant operating temperature of the electronic device under test.

Electronic devices, such as integrated circuits, are usually tested before use. Device manufacturers usually perform many electrical and physical tests to ensure that the device is free of defects and that the device functions according to its specifications. Common forms of device testing include burn-in tests and electrical performance tests.

The operating temperature of the electronic device under test ("DUT") is an important test parameter that usually requires careful monitoring and / or adjustment. For example, electrical test procedures can specify many specific test temperatures or specific ranges of test temperatures. As a result, the prior art was full of other forms of temperature control systems, heat sink components, heater elements designed to heat and cool and otherwise control the operating temperature of the DUT. This temperature control system is designed to keep the DUT operating temperature constant during the electronic test procedure. However, if the DUT shows a sudden or excessive internal temperature change during testing, it may be difficult to control the temperature of the DUT, and electronic devices in the DUT often generate heat that causes such internal temperature changes. In the prior art configuration, it would not be possible to efficiently and effectively compensate for the rapid temperature change generated by the DUT.

A preferred embodiment of the invention is recognized as a temperature control device comprising a mini fluid-cooled heat sink with an integrated heater and sensing element. The device can be used as part of a temperature control system that provides a controlled temperature plane to an electronic DUT such as a semiconductor device during testing. According to one exemplary embodiment, the liquid-cooled heat sink includes two internal cooling passages and heat transfer sections having inlets and outlets. The heat transfer portion may be disposed in the separation plane and include cooling fins. The device is arranged with two integrated heaters. Another embodiment is shown for the location of the integrated heater. According to another exemplary embodiment, the temperature control device comprises a fluid-cooled heat sink configured to maintain the cross-sectional flow of refrigerant in three dimensions for cooling the DUT interface surface. The heat sink structure may employ a three-dimensional microchannel structure that induces refrigerant flow three-dimensionally in each fluid conduit.

Throughout the drawings, like reference numerals refer to the detailed description of the invention and the appended claims, taken in conjunction with the following drawings, in which like elements designate a more complete understanding of the invention.

1 is a perspective view of a temperature control device for adjusting the temperature of an element under test.

FIG. 2 is an exploded perspective view of the temperature control device of FIG. 1, showing the cooling layer and the passage.

3 to 5 are exploded perspective views of various temperature control devices, in which heater layer positions are shown relative to the cooling layer.

6 is a perspective view of the temperature control device in which the DUT interface surface is shown.

FIG. 7 is a perspective view of the temperature control device shown in FIG. 6 with the fluid entry / exit side shown.

8 is an exploded perspective view of the temperature control device illustrated in FIGS. 6 and 7.

FIG. 9 is a plan view of one of the outer layers of the temperature control device shown in FIG. 8.

FIG. 10 is a plan view of one of the inner layers of the temperature control device shown in FIG. 8.

FIG. 11 is a schematic perspective view of an exemplary microchannel structure that may be formed within the temperature control device shown in FIGS. 6 and 7.

The temperature control device according to the present invention employs a fluid-cooled heat sink structure that maintains a cross-sectional flow of refrigerant in three dimensions in order to cool the DUT interface surface of the temperature control device. According to one exemplary embodiment, the heat sink structure includes at least two layers of heat transfer to establish a three-dimensional refrigerant flow. In another exemplary embodiment, the heat sink structure includes a microchannel structure that forces refrigerant to flow into the three-dimensional bottom within the fluid conduit or channel. Other practical embodiments may also be included within the scope and spirit of the invention.

Mini-fluid-cooled heat sinks with integrated heaters and sensing elements are used as part of the temperature control system to provide controlled temperature surfaces to electronic devices such as semiconductor devices during the test condition. In use, the semiconductor device is arranged to be in direct contact with one of an interface material, such as a device or metal plate, or an area-adapting heat spreader. In use, an integral heating element is used to heat itself and the device to a set temperature, the sensing element senses the temperature, and the refrigerant flowing through the heat sink removes excess heat from the device.

Practical temperature control devices can be designed to honor test temperatures between -55 ° C and 155 ° C. However, most electronic devices are usually tested at temperatures between -45 ° C and 120 ° C. (These exemplary temperature ranges may change in the future and the present invention is not limited to specific test temperature ranges.) The test specification of the device usually does not require a transient temperature, ie most electronic tests are performed at a substantially constant operating temperature. One advantage of the device described here is that its small size, low thermal mass, allows for very rapid calibration when the electronic heating deviates from the set temperature. In addition, the integration of the temperature control device simplifies the design and does not require additional assembly. Once assembled, the monolithic nature of the device using a thermally conductive material ensures that the fluid channel removes heat effectively and repeatedly.

1 shows a perspective view of one embodiment of a temperature control device 100 used to adjust the temperature of the DUT 102. For the purpose of describing the exemplary embodiments herein, the DUT 102 is an electronic semiconductor circuit device such as a microprocessor chip. Alternatively, the DUT 102 may be an electronic, mechanical or other device in which one or more tests are to be performed at a particular set temperature. The temperature control device 100 may cooperate with a suitable test system (not shown) to provide power supply, refrigerant flow control, input signals, and possibly other inputs to the DUT 102. Typical test systems also monitor many of the outputs and signals generated by the DUT 102 during the test procedure.

The temperature control device 100 is designed to provide a controlled temperature at the interface side or first side 103 that provides a thermal path from the temperature control device 100 to the DUT 102. The DUT 102 is preferably held against or in proximity to the interface surface 103 of the temperature control device 100. Inside the temperature control device 100, there are internal cooling passages, integrated heaters, and sensing elements. In order to regulate the temperature at the interface surface 103, the integral heater is turned on to supply heat, and the fluid flows through the cooling passages to provide cooling. The following figures and description will explain the cooling passages and the integral heater layer and their positions.

The temperature regulating device 100 may be regulated by an appropriately configured control system 101. The sensing element is used to provide an input to the control system to monitor the temperature of the temperature control device 100 and to determine when it should be heated or cooled. The control system 101 generates the control signal which functions as an input signal to the integrated heater and / or cooling system accommodated in the temperature control apparatus 100. The control signal may be generated by the control system 101 in response to one or more test criteria, operating conditions or feedback signals. For example, the control system 101 may generate a control signal in response to any of the following parameters, which parameters may include: a test temperature set in relation to the current test specification for the DUT 102; For example, input signals used by the DUT 102, such as input power signals, input voltages or input currents; A signal indicative of the real time operating temperature of the DUT 102; Signals indicative of real-time operating temperatures of internal components of the DUT 102, such as, for example, semiconductor dies; A signal representing a real time temperature of a portion of the temperature control device 100; RF signature of the DUT 102; Or other parameter.

In order to cool the temperature control device 100, the fluid passes through the first internal cooling passage 104 and the second internal cooling passage 106. (See FIG. 2) The fluid may be water, air, refrigerant, or desired. It may be another fluid material having thermal properties. The first internal cooling passage 104 has an inlet 108 and an outlet 109. The second internal cooling passage 106 has an inlet port 110 and an outlet port 111. As shown in FIG. 1, first fluid 112A enters through first inlet 108 and fluid 112B exits through first outlet 109. The second fluid 114A enters through the second inlet 110, and the second fluid 114B exits through the second outlet 111. Fluid flows through the inner passageways 104 and 106 to cool the temperature control device 100. A refrigerant system (not shown) may provide the fluids 112, 114, and cooperate with the temperature control device 100 to adjust the temperature and flow rate of the fluid. The refrigerant system pumps the fluid through the inlets 108, 110 to the temperature control device 100 and receives the fluid returned through the outlets 109, 111. The inlet and outlet ports can be designed to have internal threads such that appropriate fluid fittings (not shown) can be attached. The fluid fitting houses a fluid delivery hose or conduit that carries fluid between the temperature control device 100 and the refrigerant system.

2, an exploded perspective view of some of the layers of the cooling section of the temperature control device 100 is shown. The cooling section includes two cooling passages 104, 106 passing through the temperature control device 100. Each cooling passage has an inlet, an outlet, and a heat transfer or heat transfer layer that creates a continuous fluid conduit through the device. Inlets and outlets are disposed in cover layer 116, which may include one or more layers, depending on the design. The cover layer 116 shown in FIG. 2 has multiple layers 116A, 116B, and 116C that provide channels and passageways that direct fluid flow to other layers and separate fluid passageways. The fluid flow path through the cooling passages 104, 106 is shown in FIG. 2.

The first cooling passageway 104 opens in a passageway on the layer 116B starting at the first inlet 108 of the cover layer 116A and leading to the fluid opening 118A at the first end of the layer 116B. do. Depending on the number of layers and the first heat transfer portion or heat transfer layer, there may be a subsequent fluid opening 118. As shown in the figure, there is a fluid opening 118B in layer 116C, and a fluid opening 118C in layer 120 that is guided to the first heat transfer portion or heat transfer layer. The first heat transfer portion or heat transfer layer 122 enters the end where the fluid is near, flows across the layer and flows to the second end through various openings or passageways to exit the layer 122. There may be a plurality of fluid channels or fins 123 that are guided from the first end to the second end to help the fluid spread well in the heat transfer layer 122. The particular design of the fluid channel or fin 123 may depend on such parameters as the thermal properties of the material, the thermal and physical properties of the fluid, the flow rate of the fluid, the size of the device, and the like. At the second end of the heat transfer layer 122, the fluid passage continues into the fluid opening 119C of the layer 120, the fluid opening 119B of the layer 116C, and the fluid opening 119A of the layer 116B. And finally led to the first outlet 109.

The second cooling passage 106 of the layer 116C, beginning at the second inlet 110 of the cover layer 116A, is guided to the fluid opening 126 near the fluid opening 199B of the layer 116C. Open in passage 124 through layer 116B leading to the passage. Depending on the number of layers and the location of the first heat transfer portion or heat transfer layer, there may be a subsequent fluid opening 126. As shown, the fluid opening 126 is directed to a second heat transfer portion or heat transfer layer 120. The second heat transfer portion or heat transfer layer 120 is designed such that fluid enters near the first end, crosses the layer and flows through the various openings or passageways to the second end to exit layer 120. There may be a plurality of fluid channels or fins 121 guided from the first end to the second end to help the fluid spread in the heat transfer layer 120. The particular design of the fluid channel or fin 121 depends on such parameters as the thermal properties of the material, the thermal and physical properties of the fluid, the flow rate of the fluid, the device size, and the like. At the second end of heat transfer layer 120, fluid passage 106 is guided to fluid opening 128 of layer 116C and fluid opening 130 of layer 116B to second outlet 111. do. The fluid can flow in one direction in the cooling passages, but for improved performance, the fluid must flow in opposite directions in each passage. One goal of this design is to reduce the surface temperature gradient of the temperature control device 100.

In an exemplary embodiment, the first heat transfer portion 122 is in a first plane and the second heat transfer portion 120 is in a second plane, the first plane being closer to the interface surface 103 than the second plane. have. In practice, the two planes are parallel to each other as shown in FIG. 2. This laminated structure promotes the cross-sectional flow of the refrigerant in three dimensions. Although two heat transfer layers are shown in the figures, in actual installation, any number of heat transfer layers may be employed, either directly stacked on one another or separated by one or more other elements.

Two integrated heaters used in the illustrated temperature control device 100 include a first heater layer 132 and a second heater layer 134. In practice, various numbers of heater layers can be used. 3 to 5 show an example in which the integral heater layer is disposed inside the temperature control device 100 at various positions. In these figures, cover layer 116 is shown as a single layer but may have multiple layers as described above. The heater layers 132, 134 may be made of tortuous traces with electrical resistance on a substrate having an external connection 136 connected to the controller 101. The substrate may be made of silicon, ceramic or other suitable material. Resistance trace 138 may be configured to provide uniform heating or to provide differential heating in differential control. Where appropriate, there may be fluid openings for fluid passageways 104 and 106 in the heater layer. In FIG. 3, the heater layers 132, 134 are shown near the interface surface 103 such that the heat transfer layers 120, 122 are disposed between the heater layers 132, 134 and the cover layer 116. Since the heater layers 132 and 134 are disposed away from the cover layer 116 and the heat transfer layers 120 and 122, the fluid opening does not need to pass through the heater layer. In FIG. 4, the heat transfer layers 120, 122 are near the interface surface 103, and the heater layers 132, 134 are disposed between the heat transfer layers 120, 122 and the cover layer 116. Since heater layers 132 and 134 are disposed between cover layer 116 and heat transfer layers 120 and 122, fluid openings 118 and 128 through heater layers 132 and 134 are near the first end and With the heater layer, the fluid openings 119, 126 are near the second end as part of the fluid passageway 104, 106. A serpentine trace 138 with electrical resistance is disposed on each heater layer 132, 134 between the fluid openings. In FIG. 5, the heater layer 132 is near the interface layer 103 and the heater layer 134 is near the cover layer 116. The heat transfer layers 120 and 122 are disposed between the heater layers 132 and 134. Since the heater layer 134 is disposed between the cover layer 116 and the heat transfer layers 120, 122, the fluid openings 118, 128 passing through the heater layer 134 are near the first end and the heater layer Fluid openings 119, 126 passing through are near the second end as part of fluid passageway 104, 106. A serpentine trace 138 with electrical resistance is disposed on the heater layer 134 between the fluid openings.

One or more sensing elements are included in the temperature control device 100. The sensing element is connected to a control system or other means for monitoring sensor readings. The sensing element can be used to indicate the temperature at one or more locations in the temperature control device 100. For example, the sensor may include interface surface 103 temperature, heater layer 132, 134 temperature (separate or integrated), fluid temperature or heat transfer bed temperature (separate or integrated), and sensing is appropriate or desired. You can monitor the temperature elsewhere.

In operation, the temperature control device 100 can thermally control the DUT 102 by providing a controlled temperature surface 103 to the DUT 102 during a test condition. The DUT 102 is disposed in direct contact with the device, or uses an interface material or area-adaptive heat spreader, such as a metal plate, during use. The DUT 102 is then put into a functional test as required by the test specification. The control system 101 or test equipment monitors the temperature of the DUT 102 during the functional test and adjusts the temperature of the heating and cooling elements associated with the temperature control device 100. The integral heater layers 132, 134 turn on and off together or separately to change the power supply level to heat the device, and the cooling fluid flows through the fluid passages 104, 106 to cool the device. In one practical embodiment, the temperature of each heating element is controlled independently by adjusting each power source applied to the element.

The temperature control device 100 is configured to heat or cool the DUT by providing a thermal path directly to the DUT. In the illustrated embodiment, the thermal path to the DUT is from controlled thermal interface surface 103 to cover layer 116. In FIG. 3, the heat path includes a first heater layer 132, a second heater layer 134, a first heat transfer layer 122, and a second heat transfer layer 120. In FIG. 4, the heat path includes a first heat transfer layer 122, a second heat transfer layer 120, a first heater layer 132, and a second heater layer 134. In FIG. 5, the heat path includes a first heater layer 132, a first heat transfer layer 122, a second heat transfer layer 120, and a second heater layer 134. There may be additional configurations that provide additional thermal pathways.

Of course, the size and shape of the controlled thermal interface surface 103 of the temperature control device 100 may be suitably configured to match the size and shape of the particular DUT. For example, to test a conventional microprocessor, the device can be sized to 1 inch wide, 2 inches long, and 0.25 inches thick. (Other sizes and shapes can also be employed to accommodate particular applications.) .) Alternatively, a suitably constructed mating element formed of a thermal conductor may be disposed between the temperature control device 100 and the DUT 102. Matching elements may be desirable to accommodate the particular physical properties of the DUT or to concentrate heating or cooling in specific areas of the DUT.

As noted above, the heat transfer layers 120 and 122 may include a plurality of cooling fins constructed and arranged to promote heat transfer from the fluid to the refrigerant. In addition, a plurality of parallel cooling fins are parallel to the fluid flow path in the heat transfer layers 120, 122. In a practical embodiment, each cooling fin is approximately 0.012 inches thick. And neighboring cooling fins are approximately 0.012 inches apart. Alternatively, the heat transfer layer may employ suitable cooling fins, and the particular design may depend on parameters such as heat characteristics of the heat sink material, heat and physical properties of the coolant, flow rate of the coolant, size of the heat transfer layer, and the like.

An electrically conductive “ink” can be used to form the tortuous trace 138 with electrical resistance on the substrate. According to one practical embodiment, the conductive ink comprises nickel, tungsten, or another alloy having a relatively high electrical resistance. The substrate is patterned, the conductive ink printed on the surface of the substrate and the substrate can be bonded to additional layers by lamination. Signal wires or leads 136 are soldered or otherwise attached to respective traces to convey respective heater control signals from the control system. The electrical heating element traces are not exposed to the DUT.

Many fabrication methods can be used to make the temperature control device 100. In one embodiment, once all the layer substrates are fabricated in a “green” ceramic state, the layers are then united once the fluid channels, tortuous metal traces with electrical resistance, sensors, and connections are formed on the substrate. It is joined by co-firing to form a monolithic structure. In another embodiment, once the layer substrate is silicon and fluid channels, tortuous metal traces with electrical resistance, sensors and connections have been formed in the substrate, the layers may be subjected to eutectic bonding, or other high temperature conductive bonding processes. Are combined by.

6-11 show various views of another temperature control device 200 constructed in accordance with the present invention. Like the temperature control device described above, the device 200 generally includes an interface surface 202 configured to provide a thermal path to the DUT, and to maintain a cross-sectional flow of refrigerant in three dimensions to cool the interface surface 202. A configured fluid-cooled heat sink structure and a heater assembly 206 configured to heat the interface surface 202.

The heater assembly 206 may be configured as described above in connection with the apparatus 100. Heater assembly 206 includes one or more electric heater elements coupled to a substrate. As shown in FIG. 8, the heater assembly 206 may include a number of terminals or contact points (hidden in the drawing) that receive one or more heater control signals. In a typical installation, control signals are supplied through the holes in the heat sink in the middle of the terminals on the heater assembly 206. In operation, the interface surface 202 is maintained against a DUT (not shown), the heater assembly 206 is controlled to regulate the heat applied to the DUT, and the refrigerant passes through the heat sink structure 204 Pass by and adjust the temperature of the DUT. The flow rate of the coolant and / or the temperature of the coolant may be controlled by a coolant flow control system (not shown) coupled to the apparatus 200. In this regard, the device 200 includes one or more fluid inlets 210 and one or more fluid outlets 212 that are formed in the device to receive a flow of refrigerant. For clarity, the fluid coupling elements for the inlet 210 and the outlet 212 are not shown in connection with the device 200.

The temperature control device 200 is preferably formed of a plurality of layers as best shown in FIG. 8. In the illustrated embodiment, a heater assembly 206, a first cover layer 214, a first intermediate layer 216, a plurality of microchannel layers 218, a fluid inlet and a fluid outlet are formed. A second cover layer 222 having a second intermediate layer 220 and a fluid inlet and a fluid outlet. The various layers are joined together using one or more known techniques such as bonding, soldering, adhesives, and the like. After the stacking is completed, the fluid inlet and outlet formed in the second intermediate layer 220 and the second cover layer 222 form the fluid inlet 210 and the fluid outlet 212.

In a practical embodiment of the temperature control device 200, the first cover layer 214 is formed of copper, the first intermediate layer 216 is formed of a ceramic substrate material, and each of the microchannel layers 218 is formed of copper. The second intermediate layer 220 is formed of a ceramic substrate material and the second cover layer 222 is formed of copper. The first and second intermediate layers 216, 220 function to "isolate" the thermal expansion effect and the contraction effect of the copper layer from the heater assembly 206 (in an exemplary embodiment, based on ceramic). The layers are joined together in a manner that forms a fluid seal such that cooling fluid is maintained in the appropriate channel and flow path within the heat sink structure 204. In other words, the heat sink structure 204 is formed such that (ideally) the cooling fluid enters only through the fluid inlet 210 and exits through the fluid outlet 212 only.

Referring to FIG. 10, each microchannel layer 218 includes ribs 224 that separate adjacent fluid conduits 226 from each other. The microchannel layer 218 shown in FIG. 10 includes seven ribs 224 and eight conduits 226. After several microchannel layers 218 are stacked together, ribs 224 form a “wall” between adjacent conduits 226. According to one practical embodiment, the ribs 224 are each approximately 0.020 inches wide, each conduit 226 is approximately 1.850 inches long, and (after lamination) the heat sink structure is approximately 0.158 inches thick. Of course, these dimensions can be varied to accommodate different applications and different DUT sizes.

The temperature control device 200 is suitably configured to establish the cross-sectional flow of the refrigerant in the heat sink structure 204. In an exemplary embodiment, the fluid conduits 226 are coplanar and parallel. In addition, one subset of the fluid conduits 226 receives the refrigerant flow in the first direction while the other subset of the fluid conduits 226 receives the refrigerant flow in the second direction. Preferably, the first direction is opposite to the second direction. With reference to FIG. 9, device 200 maintains cross-sectional flow of refrigerant by directing the refrigerant to some fluid inlet 210. In this respect, the fluid inlets 210a-d respectively corresponding to the fluid outlets 212a-d receive the refrigerant flow in the first direction (from top to bottom in FIG. 9). In contrast, the fluid inlets 210e-h corresponding to the fluid outlets 212e-h, respectively, receive the refrigerant flow in the second direction (from bottom to top in FIG. 9). This flow pattern causes different flow directions in adjacent conduits 226. Ultimately, the refrigerant cross-sectional flow reduces the rate of heat change on the interface surface 206 and results in more effective temperature control of the DUT.

Each microchannel layer 218 also includes a web and a mesh, matrix, lattice, or similar structure 228 disposed in the fluid conduit 226. do. The web structure 228 may employ, for example, geometric patterns such as squares, triangles, circles, hexagons, and octagons. As shown in FIG. 11, an exemplary embodiment employs a hexagonal grid of web structure 228. In the illustrated embodiment, the web structure of each microchannel layer 218 is planar or flat such that only one hexagonal "level (horizontal plane)" is placed in each microchannel layer 218. The web structure 228 of the adjacent stacked microchannel layer 218 allows the web structure 228 to create a three-dimensional microchannel structure that is disposed within the multiple fluid conduits 226 when the heat sink 204 is formed. So that they are staggered or split. 11, three branched web structures 228 are shown forming such a three-dimensional microchannel structure.

The resulting three-dimensional microchannel structure is configured to induce refrigerant flow three-dimensionally within each fluid conduit. Due to the branched nature of the individual web structures 228, the refrigerant will flow laterally through the three-dimensional microchannel structure, while flowing vertically on or below the individual web structure levels. Individual web structures 228 can be arranged and joined together so that a continuous heat transfer path from top to bottom of heat sink structure 204 is formed to improve heat transfer efficiency.

In the exemplary embodiment shown, the fluid conduits 226 and each microchannel structure are adjacent to each other. In another embodiment (not shown), the first subset of fluid conduits is disposed in one layer, the second subset of fluid conduits is disposed in a second layer below the first layer, and both sets of fluid conduits are interfaced. Disposed on face 206. Refrigerant cross-sectional flow can be established by directing the refrigerant in the manner described above and / or in one direction through the first subset of fluid conduits and in a second direction through the second subset of fluid conduits.

The stacked design of such a device allows flexibility to match heat sink efficiency and allows for pressure drop across the heat sink by simply changing the number of layers. In this respect, more layers make the heat sink efficiency of removing heat higher, which in turn leads to better response times for active thermal control systems. The additional layer also causes a low pressure drop as the cooling fluid flows through the heat sink. The low pressure drop results in a low cooling fluid inlet demand pressure, which is desirable in practical applications. The additional layer also causes high thermal mass for the heat sink. As a result, the stacked heat sink design facilitates a fast and cost effective supply of the device optimized for a given application by allowing the designer to break the balance between thermal efficiency and thermal mass.

The preferred embodiment has been described above. However, one of ordinary skill in the art having read the foregoing description will understand that changes and modifications can be made to the preferred embodiments without departing from the scope of the invention. It is intended that such other changes or modifications fall within the scope of the invention as expressed in the claims set forth below.

Claims (23)

An interface surface configured to provide a thermal path to the device under test ("DUT"), A fluid-cooled heat sink having a first heat transfer portion in a first plane and a second heat transfer portion in a second plane, the first plane being closer to the interface surface than the second plane; One or more integral heater assemblies, Temperature control device. The method according to claim 1, Further comprising one or more thermal sensing elements, Temperature control device. The method according to claim 1, The first heat transfer portion includes one or more flow channels, Wherein the second heat transfer portion comprises one or more flow channels, Temperature control device. The method according to claim 1, The first heat transfer part has a flow path in a first direction, The second heat transfer part has a flow path in a second direction, Temperature control device. The method according to claim 4, The flow path in the first direction is opposite to the flow path in the second direction, Temperature control device. The method according to claim 1, The one or more integrated heater assemblies are planar and parallel to the interface surface, Temperature control device. The method according to claim 1, The one or more integrated heater assemblies, A substrate, and at least one heating element formed on the substrate, Temperature control device. The method according to claim 7, The at least one heating element comprises one or more tortuous traces having electrical resistance, Temperature control device. The method according to claim 1, Wherein each of the one or more integrated heater assemblies have a power level independently adjustable Temperature control device. An interface surface configured to provide a thermal path to the device under test ("DUT"), A fluid-cooled heat sink structure configured to maintain cross-sectional flow of refrigerant in three dimensions to cool the interface surface; A heater assembly configured to heat the interface surface; Temperature control device. The method according to claim 10, The fluid-cooled heat sink structure is A first fluid conduit for receiving a refrigerant flow in a first direction; A first three-dimensional microchannel structure disposed in the first fluid conduit, the first three-dimensional microchannel structure configured to induce a coolant flow three-dimensionally within the first fluid conduit, A second fluid conduit for receiving refrigerant flow in a second direction different from said first direction; A second three dimensional microchannel structure disposed in the second fluid conduit, the second three dimensional microchannel structure configured to induce a coolant flow in three dimensions within the second fluid conduit; Temperature control device. The method according to claim 11, Wherein the first and second fluid conduits are coplanar, Temperature control device. The method according to claim 12, Wherein the first and second fluid conduits are adjacent to each other, Temperature control device. The method according to claim 11, The first fluid conduit is disposed above the second fluid conduit, Wherein the first and second fluid conduits are disposed on the interface surface, Temperature control device. The method according to claim 10, The heater assembly disposed between the interface surface and the fluid-cooled heat sink structure, Temperature control device. The method according to claim 10, The fluid-cooled heat sink structure is The first layer, A second layer below the first layer, A first plurality of flow channels formed in the first layer to receive refrigerant flow within the fluid-cooled heat sink structure; A second plurality of flow channels formed in the second layer to receive refrigerant flow within the fluid-cooled heat sink structure; Temperature control device. The method according to claim 16, And the first layer and the second layer are parallel to each other. The method according to claim 16, The first plurality of flow channels are configured to maintain a first flow path having a first direction, Wherein the second plurality of flow channels are configured to maintain a second flow path having a second direction different from the first direction, Temperature control device. The method according to claim 18, Wherein the first flow path is opposite of the second flow path, Temperature control device. An interface surface configured to provide a thermal path to the device under test ("DUT"), A fluid-cooled heat sink structure configured to maintain a cross-sectional flow of refrigerant in three dimensions to cool the interface surface, The fluid-cooled heat sink structure is A first fluid conduit for receiving a refrigerant flow in a first direction; A first three-dimensional microchannel structure disposed in the first fluid conduit, the first three-dimensional microchannel structure configured to induce a coolant flow three-dimensionally within the first fluid conduit, A second fluid conduit for receiving refrigerant flow in a second direction different from said first direction; A second three dimensional microchannel structure disposed in the second fluid conduit, the second three dimensional microchannel structure configured to induce a coolant flow in three dimensions within the second fluid conduit; Temperature control device. The method of claim 20, Further comprising a heater assembly configured to heat the interface surface, Temperature control device. The method of claim 20, Wherein the first and second fluid conduits are coplanar, Temperature control device. The method of claim 20, The first fluid conduit is disposed above the second fluid conduit, Wherein the first and second fluid conduits are disposed on the interface surface, Temperature control device.

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