Probe card for electronic device test equipment with improved thermal management

Abstract

The present invention provides a probe card (10) configured to be mounted in contact with a test cell (17) of an electronic device testing apparatus, the probe card (10) including at least one probe head (11) containing a plurality of contact probes (1) and disposed between a device under test (13) and a space transformer (14) in contact with a main board (15) provided with a stiffener (16) configured to be connected to the test cell (17). Preferably, the probe card (10) The device includes a heat dissipation device (20) provided with at least one thermal pipe (19), which thermally connects the probe card (10) to the test cell (17) and is configured to dissipate heat generated inside the probe card (10) during operation of the probe card.

Description

[Technical Field]

[0001] The present invention relates to a probe card for testing apparatus for electronic devices integrated on a semiconductor wafer. The following description is given with reference to its field of application only for the purpose of simplifying the description of the invention. [Background technology]

[0002] As is well known, a probe card is essentially a device configured to electrically connect a plurality of contact pads of a microstructure, in particular an electronic device integrated on a wafer, to corresponding channels of a test apparatus that performs the test.

[0003] Testing performed on integrated devices is used to detect and isolate defective devices early in the manufacturing process. Typically, probe cards are used to electrically test devices integrated on wafers or chips before they are cut or singulated and assembled into encapsulating packages.

[0004] The probe card comprises a probe head that essentially includes a plurality of movable contact elements or contact probes, each having at least one end or contact tip configured to abut a corresponding one of a plurality of contact pads of a device under test. In this specification and below, the terms "end" or "tip" refer to the end of said probe, which need not necessarily be pointed.

[0005] It is well known that the effectiveness and reliability of measurement tests depend, among other factors, on creating a good electrical connection between the device under test and the test equipment, and therefore on establishing optimal probe / pad electrical contact.

[0006] Among the types of probe heads used to test devices integrated on wafers in the technical field under consideration, so-called vertical probe heads are widespread, in which the contact probes are positioned substantially perpendicular to the plane in which the device under test lies.

[0007] In particular, a vertical probe head comprises a plurality of contact probes held by at least one plate or guide, typically a pair of plates or guides, which are substantially planar and parallel to one another, spaced apart to provide space or clearance to allow movement and possible deformation of the contact probes during testing, and which are provided with suitable guide holes configured to slidably receive the contact probes.

[0008] More specifically, the pair of guides comprises an upper guide (upper die) and a lower guide (lower die), both of which are provided with guide holes through which the contact probes slide axially, and which are usually made of a special alloy wire, also known in the art as a needle, with good electrical and mechanical properties, where the term "lower" usually refers to the guide closer to the device under test.

[0009] A good connection between the contact probes of the probe head and the contact pads of the device under test is ensured by pressing the probe head against the device itself, the contact probes being movable within guide holes in the upper and lower guides, and during this pressing they flex within the gap between the two guides and slide within the guide holes that accommodate the contact probes.

[0010] Bending of the contact probe within the gap can be assisted and guided by appropriate configurations of the probe itself or the guide, in particular by using pre-deformed contact probes or by appropriately shifting the guide carrying them laterally, in a direction approximately parallel to the plane of the device under test and the guide.

[0011] Typically, probe heads are used in which the probes are not fixedly fastened but remain interfaced to a suitable main board and connected to the test equipment; in this case, they are called unblocked probe heads. The main board is usually fabricated using printed circuit or PCB ("printed circuit board") technology, also known as the main PCB, which allows for larger boards with active areas containing contact pads. However, probe cards fabricated using PCB technology have significant limitations regarding the minimum achievable center-to-center distance (pitch) of contact pads, so PCB technology is typically only used to form main boards, which have relatively less stringent pad-to-pad distance constraints than the device under test.

[0012] Relaxation of the distance constraints between contact pads, particularly the spacing between adjacent pads on the main board, is made possible by the use of intermediate boards or space transformers, whose opposite faces have different center-to-center distances and whose contact pads are suitably connected by connections, particularly metal tracks, made within the space transformer itself.

[0013] In this case, the contact probe has a further end or contact head adapted to abut against a plurality of contact pads formed on a first surface of the space transformer, in particular the probe head and therefore the surface arranged towards the device under test.

[0014] Good electrical contact between the contact probe and the space transformer is ensured, as well as contact with the device under test, by pressing the probe, particularly its contact head, against contact pads fabricated on the space transformer.

[0015] Additionally, the main board is typically kept in place by stiffeners.

[0016] The assembly of the probe head, main board, intermediate board or space transformer, and stiffeners forms a probe card.

[0017] In vertical probe technology, it is particularly important to ensure good connection between the contact probe and the device under test at its contact tip, and between the contact probe and the test equipment at its contact head, and therefore at the space transformer; this connection plays a particularly important role when testing integrated circuits made according to the latest integration technologies, but because the contact pads on the device under test are very close together and very small in size, there are constraints that make it incompatible with the PCB technology that forms the main board of the probe card, as mentioned above.

[0018] The relative alignment of the components that make up the probe card has also been found to be a crucial parameter for the proper operation of the probe card itself, and the various techniques used to fabricate these components can cause flatness problems that complicate the overall construction of the probe card, particularly the relative alignment of the intermediate substrate or space transformer and the main board. Unfortunately, even with the presence of stiffeners that increase the rigidity and durability of the entire assembly, it is not possible to fully eliminate flatness defects in the space transformer and ensure accurate and complete contact with the main board.

[0019] The picture is further complicated by the operating temperature of the probe card itself, especially during test operations at extreme temperatures. In this case, the thermal expansion of the components of the probe card can affect their normal behavior due to the different thermal expansion coefficients of the different materials from which they are made. In fact, the components of the probe card are typically fastened together using screws, which tend to cause board buckling due to the restraining forces on the different boards, especially during temperature tests, and can lead to malfunction of the entire probe card, even when the contact probes of the probe head are not in contact with the contact pads of the device under test. Furthermore, during test operations, the contact probes heat up due to the passage of multiple signals, which increases the internal heat of the probe head, especially in the case of probe heads with a large number of contact probes.

[0020] Similarly, when the contact probes contact the pads of the space transformer and transmit signals therethrough, unwanted heat is generated which builds up inside the probe card.

[0021] This problem is particularly pronounced in large probe cards, such as those used to test memory devices like DRAMs, and in general for multi-dice testing, where the uncontrolled thermal expansion of components can lead to major problems during testing.

[0022] The technical problem of the present invention is to provide a probe card having structural and functional features that improve the thermal management of probe cards, control the thermal expansion of the elements that make up the probe card, while overcoming the limitations and drawbacks that still affect probe cards made with known techniques, facilitate the removal of heat generated during test operations, and limit the increase in operating temperature of the probe card and the probe heads contained therein. Summary of the Invention

[0023] The solution underlying the present invention is to provide a probe card with a heat distribution device, generally designated as a thermal pipe, with suitable elements arranged for heat exchange.

[0024] Based on the above solution, the technical problem is solved by a probe card configured to be mounted on an electronic device testing apparatus and to contact a test cell of the apparatus, the probe card comprising at least one probe head containing a plurality of contact probes and arranged between a device under test and a space transformer configured to be connected to the test cell and to contact a main board provided with a stiffener. Preferably, the probe card comprises a heat dissipation device provided with at least one thermal pipe, the at least one thermal pipe thermally connecting the probe card and the test cell and configured to realize the dissipation of heat generated inside the probe card during operation of the probe card.

[0025] More particularly, the invention comprises the following additional optional features, taken individually or in combination as appropriate:

[0026] The at least one thermal pipe may be passive and made of a material having a thermal conductivity greater than 100 W / (m·K), preferably greater than 500 W / (m·K).

[0027] More particularly, said at least one thermal pipe may be made of a material selected from copper, aluminum, aluminum nitride, silicon nitride, silicon carbide, and CVD-D (Chemical Vapor Deposition Diamond).

[0028] According to another aspect of the present invention, at least one thermal pipe may have a first end in thermal contact with the test cell and preferably placed on the test cell, and a second end in thermal contact with the main board and preferably placed on the main board.

[0029] More specifically, a first end of at least one thermal pipe may be positioned on a portion of a first surface of the stiffener that contacts the test cell, and further, a second end of at least one thermal pipe may be positioned on a portion of a second surface of the stiffener that contacts the main board.

[0030] According to another aspect of the present invention, the second end of the at least one thermal pipe may be associated with the first surface of the main board by any one of the following methods: crimping, welding, bonding with a thermal adhesive, or seaming.

[0031] According to yet another aspect of the present invention, the main board may include at least one contact area formed on a first surface and configured to form a support surface for a second end of at least one thermal pipe.

[0032] According to a further aspect of the invention, at least one thermal pipe may have a first end in thermal contact with the test cell and preferably placed on the test cell, and a second end in thermal contact with the space transformer and preferably placed on the space transformer, and in particular, at least one thermal pipe may penetrate the main board.

[0033] In this case, at least one thermal pipe may have a small diameter section and a section change point inside the main board, with the small diameter section extending from the section change point and penetrating the main board, and the section change point preferably being located in a portion of the main board that contacts the reinforcement.

[0034] According to another aspect of the invention, at least one thermal pipe may be of the active type using heat transfer to a liquid, in which case the heat dissipation device may comprise at least one radiator associated with the at least one thermal pipe.

[0035] In particular, at least one thermal pipe may have a first end associated with a first radiator, the first radiator being disposed on the main board with its face facing the test cell, and at least one thermal pipe may have a second end associated with a second radiator, the second radiator being disposed on the space transformer with its face facing the probe head.

[0036] According to this aspect of the invention, the at least one thermal pipe may include an evaporation chamber at its second end, through which flows a liquid produced by the probe card that converts heat into vapor, and the at least one thermal pipe may also include a condensation chamber disposed at its first end, such that the vapor is transported from the evaporation chamber along the at least one thermal pipe to the condensation chamber, where it is converted back into liquid, releasing heat to the first radiator, and the liquid then returns to the evaporation chamber.

[0037] According to another aspect of the invention, at least one thermal pipe may have a first end in thermal contact with the test cell, preferably positioned on the test cell, and at least one thermal pipe may also have a second end in thermal contact with the probe head.

[0038] According to this aspect of the invention, the second end of the thermal pipe may be located inside the housing of the probe head.

[0039] In particular, the second end of the at least one thermal pipe may be located within a cavity inside the probe head.

[0040] The heat dissipation device may further include a heat storage element associated with the second end of the at least one thermal pipe.

[0041] According to another aspect of the present invention, the heat dissipation device may further comprise a coating layer disposed on the guide of the probe head, preferably in contact with the second end of the at least one thermal pipe.

[0042] In particular, the coating layer may be made of a material having a thermal conductivity greater than 100 W / (m·K), preferably greater than 500 W / (m·K).

[0043] Furthermore, the coating layer may be made of a material selected from silicon nitride, silicon carbide, and CVD-D (chemical vapor deposition diamond).

[0044] According to yet another aspect of the present invention, the heat dissipating device may further include a core formed inside the space transformer. Preferably, at least one thermal pipe may have a first end in thermal contact with the test cell and a second end in thermal contact with the core. The core may be made of a material having a thermal conductivity greater than 100 W / (m·K), preferably greater than 500 W / (m·K).

[0045] According to this aspect of the invention, the core may have a periphery that is exposed to air outside the space transformer.

[0046] The core may in particular be made of a material having a Young's modulus value greater than 30,000 MPa, preferably greater than 1,200,000 MPa.

[0047] More particularly, the core may be made of a material selected from silicon nitride, silicon carbide and CVD-D (chemical vapor deposition diamond), preferably CVD-D.

[0048] According to another aspect of the present invention, the heat dissipation device may further comprise an air-cooled heat exchange structure including at least one exchanger and a fan coil configured to generate cooling air for the exchanger, and the heat dissipation device may further comprise a core made of a material having a thermal conductivity greater than 100 W / (m·K), preferably greater than 500 W / (m·K), and disposed inside the space transformer. In particular, the at least one thermal pipe may have a first end in thermal contact with the exchanger, and the at least one thermal pipe may further have a second end in thermal contact with the core.

[0049] According to yet another aspect of the present invention, the heat dissipation device may further include a liquid-cooled heat exchange structure including at least one microfluidic channel. The microfluidic channel may be formed inside the at least one thermal pipe and the space transformer, and a coolant may pass through the microfluidic channel. The heat dissipation device may also include a core disposed inside the space transformer and made of a material having a thermal conductivity greater than 100 W / (m·K), preferably greater than 500 W / (m·K). Preferably, the at least one thermal pipe may have a first end at an end of the microfluidic channel and a second end in thermal contact with the core.

[0050] Finally, according to this aspect of the invention, the liquid-cooled heat exchange structure may include a plurality of microfluidic channels fabricated within at least one thermal pipe and a space transformer.

[0051] The features and advantages of the probe card according to the invention will become apparent from the following description of exemplary embodiments given as non-limiting examples, with reference to the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a schematic cross-sectional view of a probe card according to one embodiment of the present invention. [Figure 2]1 is a schematic cross-sectional view of a probe card according to another embodiment of the present invention. [Figure 3A] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 3B] FIG. 3B is a schematic diagram of elements included in the probe card of FIG. 3A. [Figure 3C] FIG. 3B is a schematic diagram of elements included in the probe card of FIG. 3A. [Figure 3D] FIG. 3B is a schematic diagram of elements included in the probe card of FIG. 3A. [Figure 4] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 5] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 6] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 7] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 8] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. [Figure 9] 10 is a schematic cross-sectional view of a probe card according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] Referring now to the drawings, and particularly to FIG. 1 , a probe card manufactured in accordance with the present invention and including at least one probe head provided with a plurality of contact probes, particularly for testing electronic devices integrated on a wafer, is generally indicated at 10.

[0054] It should be noted that the drawings represent schematic diagrams of cards according to the present invention, but are not drawn to scale and are drawn to highlight important features of the present invention.

[0055] Moreover, the several aspects of the invention that are illustrated by way of example in the drawings are obviously combinable with one another and interchangeable from one embodiment to another.

[0056] Furthermore, elements that are structurally and functionally identical in the several embodiments illustrated in the various figures and described below are designated with the same alphanumeric reference numerals.

[0057] In the following description, relative terms such as "above," "below," "upward," "downward," "upper," and "lower" are used solely for the purpose of simplifying the description of the illustrated solutions.

[0058] Finally, the representation of a particular shape (circular, rectangular) or arrangement of elements (parallel, orthogonal, consecutive), and the term "substantially" are always intended in relation to physical rather than geometrically abstract elements, so the latitude introduced by the transition from the purely mathematical / geometric world to the real world must always be taken into account.

[0059] 1, the probe card 10 includes a probe head 11 that houses a plurality of contact probes 1. The probe head 11 shown is an unblocked probe vertical type, and includes at least one upper plate or guide 2 and one lower plate or guide 3, each having an upper guide hole 2A and a lower guide hole 3A, through which the contact probes 1 slide.

[0060] As is conventional in the art, the term "lower guide" refers to a guide positioned adjacent to a device under test, and the term "upper guide" refers to a guide positioned adjacent to a test apparatus connected to the probe card 10 including the probe head 11 when the probe card 10, and therefore the probe head 11, is mounted and in operation as an end element of the test apparatus.

[0061] 1, the probe head 11 also comprises an intermediate plate or guide 4 arranged between the upper guide 2 and the lower guide 3, particularly adjacent to and parallel to the latter, which likewise has an intermediate guide hole 4A through which the contact probe 1 slides. This embodiment with three guides is merely exemplary, and the probe head 11 may comprise any number of guides, one or more.

[0062] The probe head 11 also comprises a receiving element or housing 5 which integrates the upper guide 2, the lower guide 3 and the intermediate guide 4 with one another and is configured to surround the contact probe 1, with a free space or gap 6 defined inside the housing 5, in particular between the upper guide 2 and the intermediate guide 4, which gap 6 allows the contact probe 1 to bend and deform during operation of the probe head 11.

[0063] Each of the contact probes 1 comprises at least one first end or contact tip 1A configured to abut a corresponding contact pad 13A of a device under test 13, particularly integrated on a semiconductor wafer 12, to establish a desired contact, particularly an electrical contact, between the contact probes 1 of the probe head 11 and the contact pad 13A of the device under test 13.

[0064] Each contact probe 1 further comprises a second end or contact head IB configured to establish contact with a main board 15 or main PCB for connection to a plate of a test apparatus, also referred to as a test cell 17. A rod-shaped probe body 1C is arranged between the contact head 1B and the contact tip 1A and is disposed substantially along the longitudinal extension direction of the contact probe 1, in particular perpendicular to the plane π in which the semiconductor wafer 12 on which the devices under test 13 are integrated is disposed, and along the Z axis of the local coordinate system of FIG.

[0065] The upper guide 2, the lower guide 3, and the middle guide 4 are plate-like elements arranged parallel to one another and to the plane π of the semiconductor wafer 12 and therefore to the plane π of the device under test 13. Preferably, as understood in relation to the prior art, the upper guide 2, the lower guide 3, and the middle guide 4 are shifted from one another along a direction tangential to the plane π of the semiconductor wafer 12 along the x-axis of the local coordinate system of FIG. 1 so as to give the contact probe 1 a preferential bending direction. This guide shift causes the guide holes formed in the guides and accommodating the same contact probe to no longer align with one another in a direction perpendicular to the plane π of the semiconductor wafer 12, i.e., along the z-axis of the local coordinate system of FIG. 1, bending the probe body 1C of the contact probe 1 and determining its preferential bending direction.

[0066] The probe card 10 further includes an intermediate plate arranged between the probe head 11 and the main board 15 and configured to perform spatial transformation, particularly with respect to the distribution of contact pads on its opposite surface, and for this reason is shown as a space transformer 14.

[0067] The space transformer 14 has a first surface FA facing the main board 15, which is the top surface according to the local coordinate system of Figure 1, and has a first plurality of contact pads, also referred to as tester-side pads 14A. The space transformer 14 also has a second surface FB facing the probe head 11, which is the bottom surface according to the local coordinate system of Figure 1, and has a second plurality of contact pads, also referred to as probe-side pads 14B, against which the contact head 1B of the contact probe 1 abuts, and which are connected to the tester-side pads 14A by suitable metallization or metal tracks 14C fabricated inside the space transformer 14.

[0068] Finally, the probe card 10 includes a stiffener 16 associated with the main board 15, which is configured to improve its flatness and prevent it from bending, particularly when the temperature of the probe card 10 increases during operation, i.e., during testing operations.

[0069] Furthermore, connectors 18 , in particular clamping screws, are used to integrate the test cell 17 with the probe card 10 , in particular with the main board 15 .

[0070] During operation of the probe card 10, i.e., during testing of the devices under test 13 integrated on the semiconductor wafer 12, several elements constituting the probe card 10 become sources of heat flow, in particular: A first heat flow H1 is exchanged between the semiconductor wafer 12, in particular the device under test 13 integrated thereon, and the probe head 11; A second heat flow H2 is exchanged between the probe head 11 and the space transformer 14, A third heat flow H3 is exchanged between the probe head 11 and the main board 15 through the air surrounding the probe head 11 inside the probe card 10, A fourth heat flow H4 is generated inside the space transformer 14 and moves toward the main board 15. A fifth heat flow H5 is generated within the main board 15 and moves towards the stiffener 16.

[0071] The first heat flow Hl is defined as a function and relates to the test operation and the signals transmitted by the contact probes 1 of the probe head 11 to the contact pads 13A of the device under test 13 integrated on the semiconductor wafer 12 to perform testing of the device.

[0072] The second heat flow H2 is due to heating of the contact probe 1 inside the probe head 11 due to the Joule effect, and is due to a signal that passes through the above probe and is transmitted to the space transformer 14 when the contact head 1B of the contact probe 1 comes into contact with the probe side pad 14B of the space transformer 14.

[0073] The third heat flow H3 is related to the heating of the air inside the probe card 10 due to heat transfer from the support structure (chuck) of the semiconductor wafer 12, which heats up especially during test operations.

[0074] A fourth heat flow H4 and a fifth heat flow H5 are always developed inside the space transformer 14 and the main board 15, respectively, due to the Joule effect and signals transmitted inside these elements.

[0075] Instead, other elements of the probe card 10 are responsible for heat dispersion, in particular, the air present between the main board 15 and the test cells 17 generates a first heat dispersion flow F1, which moves towards the test cells 17, A second heat dispersing flow F2 is generated by the connector 18 and travels towards the test cell 17; A third heat dispersing flow F3 occurs between the reinforcement 16 and the test cell 17 in the contact area between these elements, and the third heat dispersing flow F3 also moves towards the test cell 17.

[0076] It can be seen that the space transformer 14 and the probe head 11 are the elements contained in the probe card 10 that are most exposed to stress due to high temperatures.

[0077] According to the present invention, the probe card 10 advantageously further comprises a heat dissipation device 20 which can improve the heat exchange of the probe card 10 and reduce problems associated with overheating of its elements.

[0078] 1, the heat dissipation device 20 comprises at least one thermal pipe 19, and in the illustrated example comprises a pair of thermal pipes 19 arranged inside the stiffener 16 and capable of bringing the main board 15 and the test cell 17 into thermal contact. The presence of two thermal pipes 19 in the heat dissipation device 20 is shown only as a non-limiting example, and it is clear that the heat dissipation device 20 may comprise one or any number of thermal pipes 19.

[0079] In particular, each thermal pipe 19 has a first end 19A in thermal contact with the test cell 17, preferably placed on the test cell 17, and a second end 19B in thermal contact with the main board 15, preferably placed on the main board 15. The first end 19A is arranged on a first face FC of the stiffener 16, in particular the upper face in consideration of the local coordinate system of FIG. 1, i.e., the face facing the test cell 17, and the second end 19B is arranged on a second face FD of the stiffener 16, in particular the lower face in consideration of the local coordinate system of FIG. 1, i.e., the face facing the main board 15. To achieve thermal connection between the main board 15 and the test cell 17, each thermal pipe 19 is positioned so that the first end 19A is arranged on a portion of the first face FC of the stiffener 16 that contacts the test cell 17, and the second end 19B is arranged on a portion of the second face FD of the stiffener 16 that contacts the main board 15. Additionally, the first end 19A has an extended support structure on the first face FC of the stiffener 16.

[0080] Preferably, the thermal pipes 19 of the heat dissipation device 20 provide an additional heat dissipation flow F that can significantly improve the dissipation of heat generated inside the probe card 10. *For this purpose, the thermal pipe 19 is preferably made of a material with a high thermal conductivity λ, chosen from metals or inorganic materials.

[0081] Preferably, the thermal pipe 19 is made from a material having a thermal conductivity λ greater than 100 W / (m·K), preferably greater than 500 W / (m·K).

[0082] More specifically, the thermal pipe 19 may be made of a material selected from copper, aluminum, aluminum nitride, silicon nitride, silicon carbide, and CVD-D (chemical vapor deposition diamond).

[0083] The second end 19B of each thermal pipe 19 rests on the first face FE of the main board 15, in particular the top face according to the local coordinate system of Figure 1, and the first face FE of the main board 15 is in contact with the second face FD of the stiffener 16. Alternatively, the second end 19B can be welded or thermally glued to the first face FE of the main board 15, or can be integrated by seaming (crimping).

[0084] In a preferred embodiment, the thermal pipe 19 is formed by a column of metal, for example copper, which is crimped to achieve a composite material and is then wrapped at the first end 19A and second end 19B of the thermal pipe 19 to have a final planar configuration and a monolithic block with improved thermal conductivity in the vertical direction.

[0085] Additionally, suitable contact areas or thermal pads 15E may be disposed on the first face FE of the main board 15 to form a support surface for the second ends 19B of the thermal pipes 19.

[0086] It is emphasized that the presence of the heat dissipation device 20 and its thermal pipes 19, which thermally connect the main board 15 and the test cells 17, substantially achieves an increase in the thermal conductivity of the main board 15 while improving the dissipation of heat generated by the probe card 10 during its operation.

[0087] According to another embodiment, as shown schematically in FIG. 2, the thermal pipe 19 of the heat dissipation device 20 may be formed to pass completely through the main board 15 and be in thermal contact with the space transformer 14 .

[0088] Furthermore, each thermal pipe 19 can be formed to have a small diameter section 19S inside the main board 15. In this case, each thermal pipe 19 has a first end 19A arranged on the first face FC of the stiffener 16, a second end 19B arranged on a second face FF opposite the first face FE of the main board 15 and in contact with the space transformer 14, particularly on the lower face according to the local coordinate system of FIG. 2, and a section change point 19C arranged on the first face FE of the main board 15, from which the small diameter section 19S extends, penetrating the main board 15.

[0089] In that case, it is also possible to arrange suitable contact areas or thermal pads 15F on the second face FF of the main board 15 to form a support surface for the second ends 19B of the thermal pipes 19.

[0090] The thermal pipe 19 is suitably made of a material having a high thermal conductivity λ selected from metals or inorganic materials, having a thermal conductivity λ of greater than 100 W / (m·K), preferably greater than 500 W / (m·K), and selected from copper, aluminum, aluminum nitride, silicon nitride, silicon carbide, and CVD-D (chemical vapor deposition diamond) as described above.

[0091] The thermal pipe 19 described above in connection with the embodiment of Figures 1 and 2 is in the form of a substantially solid metal bar and is generally referred to as a passive thermal pipe.

[0092] It is also possible to use active thermal pipes 19 that transfer heat to the liquid, in which case the heat dissipation device 20 comprises at least one thermal pipe 19 and at least one radiator associated with the thermal pipe 19 that transfers heat to the outside of the thermal pipe 19 itself.

[0093] 3A, the heat dissipating device 20 includes a pair of thermal pipes 19, each of which has a first end 19A associated with a first radiator 21A disposed on the main board 15, particularly on a first face FE facing the test cell 17, and a second end 19B associated with a second radiator 21B disposed on the space transformer 14, particularly on a second face FB facing the probe head 11. Preferably, the first radiator 21A is disposed on a portion of the first face FE of the main board 15 that is not in contact with the stiffener 16, and the second radiator 21B is disposed on a portion of the second face FB of the space transformer 14 that is not in contact with the probe-side pads 14B and that abuts against the contact head 1B of the contact probe 1 of the probe head 11, so as not to interfere with the operation of the probe card 10 and the probe head 11 included therein.

[0094] Each active thermal pipe 19, as shown schematically in FIG. 3B, has an evaporation chamber 22B at its second end 19B through which liquid flows, where it is converted to vapor by heat produced by the probe card 10 and transported along the thermal pipe 19 to a condensation chamber 22A located at its first end 19A, where it is converted back into liquid and heat is released to a first radiator 21A located on the main board 15, where the liquid then returns to the evaporation chamber 22B to begin the process again.

[0095] The heat dissipation device 20 thus obtained is shown schematically in Figure 3C and comprises a thermal pipe 19 arranged between a first radiator 21A and a second radiator 21B, the first radiator 21A being shown in more detail in Figure 3D, which also shows the second end 19B of the thermal pipe 19 associated with the second radiator 21B.

[0096] In a further alternative embodiment, shown diagrammatically in Figure 4, a thermal pipe 19 is formed to pass through and be in thermal contact with the housing 5 of the probe head 11 in order to remove heat produced in the probe head 11 and to cool the housing 5 itself. In particular, in this case the second end 19B of the thermal pipe 19 is located inside the housing 5.

[0097] The heat dissipating device 20 can also be formed to further comprise a coating layer 23 made of a material having a high thermal conductivity λ greater than 100 W / (m·K), preferably greater than 500 W / (m·K), arranged on one of the guides of the probe head 11 (also on the housing 5 side) that contacts the second end 19B of the thermal pipe 19. More specifically, the coating layer 23 can be made of a material selected from silicon nitride, silicon carbide, and CVD-D (chemical vapor deposition diamond).

[0098] In the example of Figure 4, the coating layer 23 is arranged on the surface of the intermediate guide 4, particularly on the upper surface when considered from the local coordinate system of Figure 4, and is also deployed on the housing 5, and the second end 19B of each thermal pipe 19 is in thermal contact with the coating layer 23 inside the housing 5.

[0099] Alternatively, as shown schematically in FIG. 5 , the thermal pipe 19 can be formed outside the housing 5, but can also be formed inside the probe head 11, in the cavity 6. In particular, the second end 19B of the thermal pipe 19 is preferably located in an area where there is no risk of the thermal pipe 19 coming into contact with the contact probes 1 during normal operation of the probe card 10. Therefore, even if the contact probes 1 are bent and deformed when their contact tips 1A are pressed against the contact pads 13A of the device under test 13, the second end 19B is appropriately located within the cavity 6. In this case, too, a coating layer 23 can be provided, which has a high thermal conductivity λ of more than 100 W / (m·K), preferably more than 500 W / (m·K), and is made of a material selected from silicon nitride, silicon carbide, and CVD-D (chemical vapor deposition diamond), and is arranged on one of the guides of the probe head 11 that contacts the second end 19B of the thermal pipe 19.

[0100] 5, the coating layer 23 is arranged on a surface of the intermediate guide 4, particularly on the upper surface when considered from the local coordinate system of FIG. 5, and the second end 19B of each thermal pipe 19 is in thermal contact with the coating layer 23 within the cavity 6, and preferably is pressed against the coating layer 23 that also extends into the cavity 6. Although not shown, it is also possible to form the coating layer 23 on the portion of the intermediate guide 4 located within the cavity 6 without having the coating layer 23 extend into the housing 5.

[0101] It is also possible to form the heat dissipation device 20 in association with a heat storage element 24B arranged in one of the guides of the probe head 11, for example the upper guide 2, such that the heat dissipation device 20 comprises a thermal pipe 19 with a second end 19B arranged inside the cavity 6, as shown in Figure 6. In particular, in the example of Figure 6, the heat storage element 24B is arranged on the face of the guide facing the cavity 6, more specifically on the underside of the upper guide 2, considered in the local coordinate system of Figure 6.

[0102] Preferably, the heat storage element 24B helps to collect and then dissipate heat generated inside the probe head 11, improving the overall thermal management of the probe card 10. Again, in order to improve heat transfer to the thermal pipes 19 inside the probe head 11, particularly to the heat storage element 24B facing the intermediate guide 4, one of the guides, for example the intermediate guide 4, can be provided with a coating layer (not shown in FIG. 6) having high thermal conductivity, as shown in the examples of FIGS. 4 and 5.

[0103] In a further alternative embodiment shown in Figure 7, the heat dissipating device 20 includes a core 25 formed inside the space transformer 14. In particular, the space transformer 14 may have a multi-layer structure and include the core 25. Preferably, the core 25 is formed of a material having a high thermal conductivity λ, i.e., a thermal conductivity λ greater than 100 W / (m K), preferably greater than 500 W / (m K). Furthermore, the second end 19B of the thermal pipe 19 is formed in thermal contact with the core 25, thereby improving heat transfer from the interior of the space transformer 14 to the thermal pipe 19.

[0104] Core 25 may also be formed with a peripheral edge 25C that is exposed to space transformer 14, or, if space transformer 14 is a multi-layer structure, to other layers that make up the space transformer, and this peripheral edge 25C may be in contact with the air surrounding probe card 10, thereby further facilitating heat dissipation from within space transformer 14. In an alternative embodiment (not shown), a conductive layer may be disposed on the surface of core 25 opposite exposed peripheral edge 25C to further facilitate heat dissipation into the air.

[0105] The presence of the core 25 made of a material with high thermal conductivity makes it possible, in particular, to optimally collect and subsequently disperse the heat generated in the space transformer 14 during the test operations performed by the probe card 10, and also makes it possible to assist in the collection and dispersal of heat generated in the probe head 11, in particular by the connection between the contact probes 1 contained therein and the space transformer 14.

[0106] Preferably, the core 25 may be made of a material with high stiffness, i.e. a high tensile modulus or Young's modulus E, in particular a value greater than 30,000 MPa, preferably greater than 1,200,000 MPa, so as to provide mechanical support for the space transformer 14, which may comprise a number of layers mechanically supported by the core 25 and suitably overlapping each other.

[0107] Additionally, the core 25 is made of a non-conductive material so as not to interfere with the electrical operation of the space transformer 14 .

[0108] The core 25 can be made in particular of silicon nitride, silicon carbide or CVD-D (Chemical Vapor Deposition Diamond), preferably CVD-D, a substantially insulating material with a high thermal conductivity λ and sufficient rigidity to support the layers of the space transformer 14, in particular organic layers configured to form organic multilayers (MLOs) or metal and ceramic layers to form ceramic-based multilayers or MLCs (Multilayer Ceramic).

[0109] The core 25 itself may be formed by bonding multiple layers of different materials to improve the mechanical performance of the core 25 while ensuring a good level of heat exchange. Among the materials used to form the different layers of the core 25, silicon nitride, silicon carbide, CVD-D (chemical vapor deposition diamond), to mention just a few, may also be used.

[0110] 8, the heat dissipation device 20 may further comprise an air-cooled heat exchange structure 26, which essentially comprises a heat exchanger 26A provided at a first end 19A of a thermal pipe 19 and a corresponding fan coil 26B configured to generate cooling air for the heat exchanger 26A. In the example shown in FIG. 8, the thermal pipe 19, particularly the second end 19B, is in thermal contact with and preferably rests on a core 25 formed in the space transformer 14.

[0111] Alternatively, as shown schematically in Figure 9, the heat dissipation device 20 may comprise a liquid-cooled heat exchange structure formed within the thermal pipes 19 and the space transformer 14, preferably in the form of microfluidic channels 27 through which a coolant 28 passes from an inlet nozzle 27A to an outlet nozzle 27B formed in a first end 19A of the different thermal pipes 19. In the example shown in Figure 9, the thermal pipes 19 each have a second end 19B that is in thermal contact with, and preferably rests on, a core 25 formed in the space transformer 14.

[0112] The microfluidic channels 27 that pass through the thermal pipes 19 and the space transformer 14 for passing the coolant 28 can be formed by laser drilling. Preferably, the microfluidic channels 27 are formed close to the core 25 to improve heat exchange with the core 25.

[0113] The presence of the cooling liquid 28 transported by the microfluidic channels 27 makes it possible to achieve liquid cooling that affects the entire space transformer 14 in addition to the thermal pipes 19, thus significantly improving the efficiency of the heat exchange achieved by the space transformer 14, and in particular its core 25.

[0114] It is obviously possible to provide a plurality of microfluidic channels inside the thermal pipe 19 and inside the space transformer 14 for transporting the cooling liquid 28 .

[0115] In conclusion, according to the present invention, advantageously, a probe card provided with a heat dissipation device having a thermal pipe can effectively dissipate heat generated in the probe card by testing an integrated device, especially when there is a test operation using a power signal, thereby enabling the probe card as a whole to have improved thermal management and reduce malfunction problems caused by deformation of its components due to heat generated inside the probe card during its operation.

[0116] It can therefore be seen that such a probe card is suitable for applications in which the entire card is significantly heated by the test operation, thereby ensuring its correct operation and avoiding deformation of its components, such as the probe head and space transformer, which may affect the successful outcome of the test.

[0117] It has been found that heat distribution is further improved when the heat distribution device comprises an active thermal pipe associated with the heat spreader. Furthermore, the temperature performance of the probe card is further improved when the heat distribution device comprises an air-cooled or liquid-cooled heat exchange structure.

[0118] Furthermore, the use of a space transformer in a probe card, which has a core made of a highly conductive material and which may have a peripheral portion exposed to air, improves the overall thermal exchange of the probe card and, if the core is suitably made of a material with sufficient rigidity, can also provide mechanical support for other layers, particularly organic layers, which may form the space transformer itself.

[0119] Obviously, in order to meet possible specific requirements, those skilled in the art can make various modifications and substitutions to the above probe card and space transformer, all of which fall within the scope of protection of the present invention as defined by the following claims.

Claims

1. 1. A probe card (10) configured to be mounted in contact with a test cell (17) of an electronic device testing apparatus, the probe card comprising: The probe card (10) includes at least one probe head (11) that accommodates a plurality of contact probes (1) and is arranged between a device under test (13) and a space transformer (14) that contacts a main board (15) provided with a stiffener (16) and is configured to be connected to the test cell (17); The probe card comprises: a heat dissipation device (20) provided with at least one thermal pipe (19); The at least one thermal pipe thermally connects the probe card (10) and the test cell (17) and is configured to achieve dissipation of heat generated inside the probe card (10) during operation of the probe card. A probe card (10).

2. 2. The probe card (10) of claim 1, wherein the at least one thermal pipe (19) is passive and made of a material having a thermal conductivity greater than 100 W / (m·K).

3. The probe card (10) of claim 2, wherein the at least one thermal pipe (19) is made of a material having a thermal conductivity greater than 500 W / (m·K).

4. 3. The probe card (10) according to claim 2, characterized in that the at least one thermal pipe (19) is made of a material selected from copper, aluminum, aluminum nitride, silicon nitride, silicon carbide, and CVD-D (Chemical Vapor Deposition Diamond).

5. 3. The probe card (10) of claim 2, wherein the at least one thermal pipe (19) has a first end (19A) in thermal contact with the test cell (17) and a second end (19B) in thermal contact with the main board (15).

6. 6. The probe card (10) of claim 5, wherein the first end (19A) is placed on the test cell (17) and the second end (19B) is placed on the main board (15).

7. 6. The probe card (10) of claim 5, wherein the first end (19A) of the at least one thermal pipe (19) is positioned on a portion of a first surface (FC) of the stiffener (16) that contacts the test cell (17), and the second end (19B) of the at least one thermal pipe (19) is positioned on a portion of a second surface (FD) of the stiffener (16) that contacts the main board (15).

8. The probe card (10) of claim 5, wherein the second end (19B) of the at least one thermal pipe (19) is associated with the first surface (FE) of the main board (15) by any one of the following methods: crimping, welding, bonding with a thermal adhesive, or seaming.

9. The probe card (10) of claim 8, characterized in that the main board (15) has at least one contact area (15E) formed on the first surface (FE) and configured to form a support surface for the second end (19B) of the at least one thermal pipe (19).

10. 3. The probe card (10) of claim 2, wherein the at least one thermal pipe (19) has a first end (19A) in thermal contact with the test cell (17) and a second end (19B) in thermal contact with the space transformer (14), and the at least one thermal pipe (19) penetrates the main board (15).

11. 11. The probe card (10) of claim 10, wherein the first end (19A) is placed on the test cell (17) and the second end (19B) is placed on the space transformer (14).

12. The probe card (10) of claim 10, wherein the at least one thermal pipe (19) has a small diameter section (19S) and a section change point (19C) inside the main board (15), and the small diameter section (19S) extends from the section change point and penetrates the main board (15).

13. The probe card (10) according to claim 12, characterized in that the section change point (19C) is located at a portion of the main board (15) that contacts the stiffener (16).

14. The probe card (10) of claim 1, wherein the at least one thermal pipe (19) is of an active type using heat transfer to a liquid, and the heat dissipation device (20) comprises at least one radiator associated with the at least one thermal pipe (19).

15. 15. The probe card (10) of claim 14, wherein the at least one thermal pipe (19) has a first end (19A) associated with a first radiator (21A) arranged on a surface (FE) facing the test cell (17) on the main board (15), and a second end (19B) associated with a second radiator (21B) arranged on a surface (FB) facing the probe head (11) on the space transformer (14).

16. the at least one thermal pipe (19) comprises an evaporation chamber (22B) at the second end (19B); In the evaporation chamber (22B), a liquid flows which is converted from heat produced by the probe card (10) into steam and is sent along the at least one thermal pipe (19) to a condensation chamber (22A) located at the first end (19A) of the at least one thermal pipe (19); In the condensation chamber (22A), the vapor is converted back into a liquid and releases the heat to the first radiator (21A), which then returns to the evaporation chamber (22B). The probe card (10) of claim 15, characterized in that

17. 3. The probe card (10) of claim 2, wherein the at least one thermal pipe (19) has a first end (19A) in thermal contact with the test cell (17) and a second end (19B) in thermal contact with the probe head (11).

18. 18. The probe card (10) according to claim 17, characterized in that the second end (19B) of the at least one thermal pipe (19) is located inside a housing (5) of the probe head (11).

19. 18. The probe card (10) according to claim 17, characterized in that the second end (19B) of the at least one thermal pipe (19) is positioned in a cavity (6) inside the probe head (11).

20. The probe card (10) of claim 19, wherein the heat dissipation device (20) further comprises a heat storage element (24B) associated with the second end (19B) of the at least one thermal pipe (19).

21. The probe card (10) according to claim 17, characterized in that the heat dissipation device (20) further comprises a coating layer (23) arranged on the guides (2, 3, 4) of the probe head (11).

22. 22. The probe card (10) of claim 21, wherein the coating layer (23) contacts the second end (19B) of the at least one thermal pipe (19).

23. 22. The probe card (10) of claim 21, wherein the coating layer (23) is made of a material having a thermal conductivity greater than 100 W / (m·K).

24. 24. The probe card (10) of claim 23, wherein the coating layer (23) is made of a material having a thermal conductivity greater than 500 W / (m·K).

25. The probe card (10) according to claim 23, characterized in that said coating layer (23) is made of a material selected from silicon nitride, silicon carbide and CVD-D (Chemical Vapor Deposition Diamond).

26. The heat dissipation device (20) further comprises a core (25) formed inside the space transformer (14); the at least one thermal pipe (19) having a first end (19A) in thermal contact with the test cell (17) and a second end (19B) in thermal contact with the core (25); The probe card (10) of claim 2, wherein the core (25) is made of a material having a thermal conductivity greater than 100 W / (m·K).

27. 27. The probe card (10) of claim 26, wherein the core (25) has a peripheral portion (25C) exposed to the air outside the space transformer (14).

28. 27. The probe card (10) of claim 26, wherein the core (25) is made of a material having a Young's modulus value greater than 30,000 MPa.

29. The probe card (10) according to claim 26, characterized in that the core (25) is made of a material selected from silicon nitride, silicon carbide and CVD-D (Chemical Vapor Deposition Diamond).

30. The heat dissipation device (20) further comprises: an air-cooled heat exchange structure (26) including at least one exchanger (26A) and a fan coil (26B) configured to generate cooling air for the exchanger (26A); and a core (25) made of a material having a thermal conductivity greater than 100 W / (m·K) and disposed inside the space transformer (14), The at least one thermal pipe (19) has a first end (19A) in thermal contact with the exchanger (26A) and a second end (19B) in thermal contact with the core (25). The probe card (10) of claim 2, characterized in that:

31. The heat dissipation device (20) further comprises: a liquid-cooled heat exchange structure including at least one microfluidic channel (27) formed inside the at least one thermal pipe (19) and the space transformer (14), through which a cooling liquid (28) passes; and a core (25) made of a material having a thermal conductivity greater than 100 W / (m·K) and disposed inside the space transformer (14), The at least one thermal pipe (19) has a first end (19A) at an end (27A, 27B) of the microfluidic channel (27) and a second end (19B) in thermal contact with the core (25). The probe card (10) of claim 2, characterized in that:

32. 32. The probe card (10) of claim 31, wherein the liquid-cooled heat exchange structure includes a plurality of microfluidic channels formed within the at least one thermal pipe (19) and the space transformer (14).

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