Probe head provided with a plurality of metallizations

Abstract

A probe head (100) having a plurality of contact probes (10) with a body (10p) extended between a first end portion (10a) and a second end portion (10b) is herein disclosed, the end portions being adapted to contact respective contact pads; the probe head has at least one guide (40) provided with guide holes (40h) for housing at least one portion of the contact probes (10), and at least one conductive portion (30) which includes at least one group of the guide holes and which is configured to contact and short-circuit a corresponding group of contact probes that are housed in said group of the guide holes and are intended to carry a given same type of signal, said conductive portion (30) being divided into at least a first portion (30a) and a second portion (30b) arranged on different faces or different guides.

Description

[0001] Title: Probe head provided with a plurality of metallizations

[0002] DESCRIPTION

[0003] Field of application

[0004] The present invention relates to a probe head adapted to perform the testing of electronic devices integrated on a semiconductor wafer, and the following description is made with reference to this field of application with the only purpose of simplifying the exposition thereof.

[0005] Prior art

[0006] As it is well known, a probe head is essentially a device adapted to electrically connect a plurality of contact pads of a microstructure, in particular of an electronic device integrated on a semiconductor wafer, with corresponding channels of a testing apparatus which performs the functionality testing thereof, in particular the electrical one, or generically the test.

[0007] The test performed on integrated circuits is useful to detect and isolate defective circuits as early as in the production phase. Usually, the probe heads are thus used for the test of the circuits integrated on wafers before cutting and assembling them inside a chip containment package.

[0008] A probe head generally comprises a plurality of movable contact probes retained by at least one pair of supports or guides which are substantially plate-like and parallel to each other. These plate-like supports are provided with suitable guide holes and are arranged at a given distance from each other so as to create a free area or air gap for the movement and the possible deformation of the contact probes, which are usually formed by wires of special alloys with good electrical and mechanical properties.

[0009] The contact probes generally extend between a first end portion, intended to contact the contact pads of the device under test, and a second end portion, intended to contact a space transformer or a printed circuit board (PCB) associated with the probe head.

[0010] In a more and more increasing number of applications, for example in high-frequency applications, at least one of the guides has a conductive portion (in particular a metallization) with the purpose of electrically connecting specific groups of contact probes to each other, forming a common conductive plane for these groups of probes. It is thereby possible to improve the performances of the probe head, since the signal is suitably distributed on several contact probes by means of the metallization.

[0011] In this type of solutions, in particular when it is desirable to form on a guide a plurality of metallizations for different signals (for example for different power supply domains), it is often complicated to arrange the various conductive portions, also taking into account the layout of the device under test which is a constraint in the design of the probe head.

[0012] The technical problem of the present invention is to devise a probe head having such functional and structural features as to allow the limitations and drawbacks still affecting known solutions to be overcome, in particular which has a greater flexibility in the design and arrangement of the metallizations on the guide / s.

[0013] Summary of the invention

[0014] The solution idea underlying the present invention is to form on a guide of the probe head at least one metallization (preferably several metallizations) with the purpose of short-circuiting contact probes with each other, forming a given conductive domain, and to let said metallization to continue also on the opposite face of the guide, for example via a metallization of the walls of one or more guide holes or through suitable conductive tracks formed in the guide. As an alternative, the same metallization can develop on faces of different guides (i.e., different metallization portions on different guides), wherein said metallization portions are electrically connected to each other by the contact probes themselves which are in contact with them (for example a sliding contact with the walls of the guide holes of the guides) . In general, the conductive portion is thus divided into different metallization portions which are formed on different faces of a guide and / or on different guides and are electrically connected to each other. There is thereby much more space for the arrangement of a single metallization, thus facilitating the design of the probe head; in the case of several metallizations, some or all of them can be divided into respective metallization portions.

[0015] Based on this solution idea, the above technical problem is solved by a probe head for testing a device under test, said probe head comprising a plurality of contact probes comprising a body extended between a first end portion and a second end portion, which are adapted to contact respective contact pads, at least one guide comprising guide holes adapted to house at least one portion of the contact probes, and at least one conductive portion which includes at least one group of the guide holes and which is configured to contact and short-circuit a corresponding group of contact probes which are housed in said group of the guide holes and are intended to carry a given same type of signal, wherein said conductive portion is divided (structured) into at least a first portion formed on a first face of the guide and a second portion formed on a second face of the guide which is opposite to the first face, said second portion being electrically connected to the first portion by means of conductive connection elements.

[0016] More particularly, the invention comprises the following additional and optional features, taken individually or if necessary in combination.

[0017] These additional and optional features are described in the dependent claims 2- 12.

[0018] According to an aspect of the present invention, the conductive connection elements can comprise at least one wall of at least one guide hole, this wall being coated with a conductive material and forming a connection between the first portion and the second portion. The first portion and the second portion are thereby electrically connected to each other by at least one metalized wall of the guide holes.

[0019] According to an aspect of the present invention, the conductive connection elements can comprise at least one conductive track which extends from the first face to the second face of the guide and is connected both to the first portion and to the second portion. The first portion and the second portion are thereby electrically connected to each other by said conductive track.

[0020] According to an aspect of the present invention, the conductive connection elements can comprise at least one contact probe of the plurality of contact probes, said contact probe acting as an electrical connection between the first portion and the second portion. The first portion and the second portion are thereby electrically connected to each other by the contact probe itself.

[0021] According to an aspect of the present invention, the conductive portion can be configured to carry a given power supply, thereby forming a given power supply domain.

[0022] According to an aspect of the present invention, the conductive portion can be configured to carry a ground signal, thereby forming a given ground domain.

[0023] According to an aspect of the present invention, the probe head can comprise, in addition to the conductive portion, at least one further conductive portion configured to include and electrically connect the holes of a further group of the guide holes to each other, said further group housing further contact probes, the contact probes and the further contact probes being connectable with respective different sources for carrying a respective different type of signal.

[0024] Possibly, this further conductive portion is divided as well into at least a first portion formed on the first face of the guide and a second portion formed on the second face of the guide which is opposite to the first face, said second portion being electrically connected to the first portion.

[0025] For example, a conductive portion can be dedicated to a power supply signal and the further conductive portion can be dedicated to a ground signal or to another power supply signal.

[0026] According to an aspect of the present invention, the probe head can comprise a plurality of conductive portions each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions.

[0027] According to an aspect of the present invention, the probe head can further comprise conductive portions configured to carry ground signals and / or operative signals from / to the device under test.

[0028] According to an aspect of the present invention, the conductive portions on a face of the guide (for example the conductive portion and the further conductive portion) can be separated from each other by at least one non- conductive area (or zone) so as not to allow the electrical connection therebetween.

[0029] According to an aspect of the present invention, the at least one guide can optionally comprise at least one dielectric coating portion which covers said at least one non-conductive area.

[0030] According to an aspect of the present invention, the guide can be a lower guide or an intermediate guide of the probe head.

[0031] According to an aspect of the present invention, the contact probes can buckling beam contact probes, wherein the body thereof has a deformation.

[0032] Furthermore, based on the above solution idea, the above technical problem is also solved by a probe head for testing a device under test, said probe head comprising a plurality of contact probes comprising a body extended between a first end portion and a second end portion, which are adapted to contact respective contact pads, a first guide provided with first guide holes for housing at least a first portion of the contact probes, a second guide provided with second guide holes for housing at least a second portion of the contact probes and separated from the first guide by an a gap (for example and air gap), and at least one conductive portion which includes at least one group of the guide holes and which is configured to contact and short-circuit a corresponding group of contact probes that are housed in said group of the guide holes and are intended to carry a given same type of signal, wherein the conductive portion is divided (structured) into at least a first portion formed at the first guide and a second portion formed at the second guide and electrically connected to the first portion by means of conductive connection elements.

[0033] This embodiment has many aspects in common with the previous one, as discussed below.

[0034] More particularly, the invention also comprises the following additional and optional features, taken individually or if necessary in combination.

[0035] These additional and optional features are illustrated in the dependent claims 14-22.

[0036] According to an aspect of the present invention, the conductive connection elements can comprise at least one contact probe of the plurality of contact probes, said contact probe thereby acting as an electrical connection between the first portion and the second portion between the first guide and the second guide.

[0037] The first portion and the second portion are thereby electrically connected to each other by the contact probe itself which extends between the first guide and the second guide.

[0038] According to an aspect of the present invention, the first portion and the second portion can be formed on respective faces of the first guide and the second guide.

[0039] According to an aspect of the present invention, the conductive portion can be configured to carry a given power supply, thereby forming a given power supply domain.

[0040] According to an aspect of the present invention, the conductive portion can be configured to carry a ground signal, thereby forming a given ground domain.

[0041] According to an aspect of the present invention, the probe head can comprise, in addition to the conductive portion, at least one further conductive portion on a same face of a guide of the first guide and second guide, this further conductive portion being configured to include and electrically connect the holes of a further group of the guide holes to each other, said further group housing further contact probes, the contact probes and the further contact probes being connectable with respective different sources for carrying a respective different type of signal.

[0042] Possibly, this further conductive portion is divided as well into at least a first portion formed at the first guide and a second portion formed at the second guide and electrically connected to the first portion.

[0043] According to an aspect of the present invention, the probe head can comprise a plurality of conductive portions each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions.

[0044] According to an aspect of the present invention, the probe head can further comprise conductive portions configured to carry ground signals and / or operative signals from / to the device under test.

[0045] According to an aspect of the present invention, the conductive portions on a same face of the guide (for example the conductive portion and the further conductive portion) can be separated from each other by at least one non-conductive area (or zone) so as not to allow the electrical connection therebetween.

[0046] According to an aspect of the present invention, the contact probes can buckling beam contact probes, wherein the body thereof has a deformation.

[0047] The features and advantages of the probe head according to the invention will be apparent from the following description of an exemplary embodiment thereof given by way of non-limiting example with reference to the attached drawings.

[0048] Brief description of the drawings

[0049] In the drawings: figure 1 schematically shows a probe head according to the present invention; figure 2A and 2B are top schematic views of respective faces of a guide of the probe head according to the present invention; figure 3 schematically shows a probe head according to an embodiment of the present invention; figures 4A and 4B are top schematic views of respective faces of a guide of the probe head according to an embodiment of the present invention; and figure 5 schematically shows a probe head according to an alternative embodiment of the present invention.

[0050] Detailed description

[0051] With reference to the figures, a probe head according to the present invention for testing a device under test (indicated herein as DUT - acronym for “Device Under Test”), for example a probe head adapted to perform the test of electronic devices integrated on a semiconductor wafer, is globally and schematically indicated with 100.

[0052] It should be noted that the figures represent schematic views and are not drawn to scale, but instead they are drawn so as to emphasize the important features of the invention. Furthermore, in the figures, the different elements are schematically depicted, and the shape thereof being can change depending on the desired application. Furthermore, it should be noted that, in the figures, identical reference numbers refer to identical elements in terms of shape or function. Finally, arrangements described in relation to an embodiment illustrated in a figure can also be used for the other embodiments illustrated in the other figures.

[0053] It is also noted that, unless it is expressly stated to the contrary, process steps can also be inverted if necessary.

[0054] Furthermore, in the context of the present invention, the term “probe head” is used to indicate a test system without being limited by the presence or absence of particular components, in addition to what is defined by the attached claims. In general, this term thus indicates a set of components which can be associated to further components (for example a space transformer and / or a PCB, or a testing apparatus) for testing devices integrated on a semiconductor wafer, and thus it generally indicates a measurement system for measuring electronic devices. Furthermore, it is noted that the association of the probe head 100 with an interface board such as a space transformer and / or a PCB is indicated in the art as “probe card”.

[0055] The probe head 100 is thus adapted to be connected to an apparatus (not illustrated in the figures) to perform the test of devices under test DUT integrated on a semiconductor wafer (indicated with the reference 23), for example high-frequency devices.

[0056] As illustrated in figure 1, the probe head 100 comprises a plurality of contact elements or contact probes 10 slidingly housed therein and adapted to connect the device under test DUT integrated on the semiconductor wafer 23 to the testing apparatus.

[0057] In order to house the contact probes 10, the probe head 100 comprises at least one guide 40 provided with guide holes 40h through which said contact elements 10 are adapted to slide.

[0058] Each contact probe 10 comprises a body lOp which extends along a longitudinal axis H-H between a first end portion 10a and a second end portion 10b, which are adapted to contact respective contact pads. By way of example, the first end portion 10a (also called contact tip) is adapted to contact contact pads DUTa of the device under test DUT integrated on the semiconductor wafer 23, while the second end portion 10b (also called contact head) is adapted to contact contact pads 20a of a space transformer or of a printed circuit board (PCB), this component being identified with the numeral reference 20 and being generally called herein as “interface board 20”. Clearly, although the end portions 10a and 10b in the attached figures end with a pointed shape, they are not limited thereto and can have any shape which is suited to the needs and / or circumstances.

[0059] It is noted that a single device under test DUT is illustrated in the example of figure 1 , including six contact pads DUTa for six corresponding contact probes, although it should be understood that the figures are only provided by way of non-limiting examples of the scope of the present invention and any, even high, number can be provided.

[0060] In the embodiment of the figures, the body lOp of the contact probes 10 has preferably a square or rectangular cross section (i.e., it is preferably rod-like), but the present invention is not limited thereto. In any case, the body lOp of the contact probes has at least one wall W adapted to contact a corresponding wall 40hW of a guide hole 40h.

[0061] In this embodiment, the contact probe 10 is a contact probe of the type which is known in the art as “buckling beam”, i.e. it has a constant cross section for substantially the whole length thereof, preferably a square or rectangular one, wherein the body lOp has a deformation for example in a substantially central position and is adapted to bend and thus to further deform during the test of the device under test DUT.

[0062] The deformation of the body lOp is generally obtained by a so-called “shifted plate guide” configuration, in which a pair of guides is first overlapped so as to align the respective guide holes. Afterwards, once the contact probes 10 have been inserted into said guide holes, the guides are spaced apart, forming an air gap therebetween, and then they are shifted, causing the above deformation of the body lOp, but without being limited to this aspect.

[0063] During the bending of the contact probes 10 (in particular during the vertical movement of the probes, indicated in the art as overtravel), a sliding contact occurs between the body lOp and the wall 40hw of the guide hole 40h. The body lOp thus comprises a portion adapted to be at least partially inserted into a guide hole 40h of the guide 40 and, during the movement of the contact probe 10, it performs a contact with said guide hole 40h, in particular a sliding contact.

[0064] It is known in the art that the fixed position of the power supply and ground signals (which is due to the layout of the pads of the device under test DUT), as well as the probe shape, limit the control of the impedance of the signals inside the probe head 100, as well as they limit the control of the noise caused on the signal probes by other close signals, which limits the frequency performances.

[0065] For this reason, in high-frequency applications (in particular RF applications - but not only), the power supply probes and also ground probes are short-circuited by means of a metallization on the guide, thereby short-circuiting probes of a same domain. Furthermore, in the case of devices with different ground / power supply domains on the device which are then joined on the PCB, the metallization allows the loop inductance between a power supply and the related ground to be reduced. Furthermore, said metallizations allow the probe burning phenomenon to be reduced, especially for the case of power supply probes.

[0066] Consider for example the case in which a given power supply of a device under test is contacted by a probe of the probe head, which is then short- circuited with other probes which carry power supply signals sharing the same power supply. Then, when the current of this power supply meets the metallization which short-circuits all the probes of this domain, it splits among all the short-circuited probes thereby allowing the equivalent resistance and inductance to be reduced compared to the case in which this current is confined in a single probe up to the PCB.

[0067] It is thus evident how the presence of metallizations on the guide, which metallizations short-circuit groups of probes and create a common conductive plane, allows the noise to be reduced and the performances of the probe head (for example, but not only, the frequency performances) to be increased.

[0068] For this purpose, according to the present invention, at least one guide (the guide 40 in the example of figures 1 to 4A-4B) of the probe head 100 comprises at least one conductive portion (indicated with the numeral reference 30 and also called “metallization” hereafter) which includes and electrically connects the holes of at least one group (indicated with the reference 40hg) of the guide holes 40h and which is configured to contact, and thus to short-circuit, a corresponding group of contact probes (globally indicated with the reference 10g), which are intended to carry a same type of signal, in particular intended to carry a given ground or power supply (or also operating signal) domain.

[0069] A given conductive domain is thereby formed on the guide 40, said conductive domain short-circuiting probes adapted to carry a given same signal, forming a common conductive plane in the probe head 100 with subsequent increase in overall performances.

[0070] In the embodiment shown in figures 1 to 4A-4B, the guide 40 is a lower guide and thus, as it is known, it is the guide which is closest to the first end portion 10a intended to contact the device under test DUT, contributing most to improving the frequency performances of the probe head 100 (because it is the guide which is closest to the device under test DUT). In this example, the holes of the group 40hg are thus the guide holes 40h of the guide 40.

[0071] In other embodiments, the guide can also be an intermediate guide arranged above the lower guide (for example arranged between the lower guide and a possible upper guide, but generally closer to the first one), wherein one or more conductive portions can be formed if necessary also on said intermediate guide, in analogy with what was discussed in relation to the guide 40. Furthermore, the probe head can comprise also an upper guide, with respective guide holes, spaced apart from the intermediate guide or from the lower guide by an air gap, wherein one or more conductive portions can be formed if necessary also on said upper guide, in analogy with what was discussed in relation to the guide 40. The presence of several guides will be discussed in greater detail below in the present description.

[0072] By way of example, the conductive portion 30 can be configured to carry a given power supply signal, thereby forming as a whole a power supply domain, or even a ground signal, forming a ground domain, or even an operative signal between the device under test DUT and the testing apparatus.

[0073] It is noted that the present invention is not limited in any way either by the configuration / arrangement of the metallization 30 or by the number thereof, and many possibilities can be provided.

[0074] Preferably, the conductive portion 30 is a surface portion, as it will be discussed below.

[0075] There can also be more than one metallization. For example, in an embodiment, it is possible to form on the guide 40 (or also on different guides) a plurality of conductive portions each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions, thus forming a plurality of different power supply domains, as well as there can be both power supply domains and ground domains.

[0076] More generally, the probe head 100 can comprise various conductive portions which short-circuit with each other respective contact probes connectable with respective different sources and thus intended to carry a respective different type of signal. These different conductive portions can be formed on a same face of the guide (like in the schematic example of figures 4A and 4B, in which there are two conductive portions for two different power supplies), or on opposite faces of the guide, or on different guides, or even based on a combination of the above configurations.

[0077] The various conductive portions are separated from each other by at least one non-conductive area (or zone) on the guide so as not to allow the electrical connection therebetween. In an embodiment, the guide 40 also comprises at least one dielectric coating portion which covers said at least one non-conductive area.

[0078] Obviously, as indicated above, the present invention is not limited by the number and / or arrangement of the conductive portions, which can be set based on the needs and / or circumstances, as described for example in the International patent application no. PCT / EP2017 / 082180 in the name of the Applicant.

[0079] As indicated above, it is desirable to form several conductive portions on the guide; further, in the arrangement of the conductive portions, the layout of the device under test DUT is to be complied with, for which reason there are some constraints in the design of the probe head, in particular as far as the arrangement of the metallizations is concerned.

[0080] For this reason, advantageously according to the present invention, the conductive portion 30 is divided into at least a first portion 30a formed on a first face (for example the face FA, i.e. the upper face) of the guide 40 and a second portion 30b formed on a second face (for example the face FB, i.e. the lower face) of the guide 40 which is opposite to the first face FA. Suitably, the second portion 30b is electrically connected to the first portion 30a by means of conductive connection elements (which will be specified below), thereby forming a single conductive portion but divided and arranged on different faces of the guide 40. In other words, the conductive portion 30 is arranged on a face of the guide and also continues on the opposite face by means of the above metallization portions (i.e., the first portion and the second portion), being thus able to short-circuit several probes of the probe head 100 and leading to more space for several conductive portions or in any case to a greater design flexibility.

[0081] In an embodiment, the conductive connection elements comprise at least one wall 40hw of at least one guide hole 40h, said wall 40hw being coated with a conductive material (which can be considered part of the conductive portion or metallization 30), which forms an electrical connection between the first portion 30a and the second portion 30b.

[0082] In other words, the first portion 30a and the second portion 30b are electrically connected to each other by at least one metalized wall of the guide holes (also indicated hereafter as “metalized holes”) .

[0083] Preferably, the whole wall of the guide hole 40h is coated by the metallization, which thus extends also in the guide hole between the first portion 30a and the second portion 30b thereby ensuring the desired electrical connection between the first portion 30a and the second portion 30b.

[0084] Furthermore, it is noted that one, only some, or all the walls of the guide hole can be metalized, as well as there can be several metalized guide holes, thus forming several conductive connection elements. In particular, although figure 1 shows for simplicity only one metalized guide hole for the connection between the first portion 30a and the second portion 30b, several guide holes (for example adjacent holes) can be used for the connection between said metallization portions.

[0085] In this example, some probes (in particular the probes on the left) are short-circuited by the upper first portion 30a, while other probes (in particular the probes on the right) are short-circuited by the lower second portion 30b, but they are still dedicated to carry the same signal (for example a same power supply) .

[0086] For convenience of description, the metalized guide hole is also indicated with the reference 100c, so as to emphasize its specific function of electrical connection between the first portion 30a and the second portion 30b.

[0087] In the intentionally schematic example of figures 2A and 2B, the first portion 30a and the second portion 30b are electrically connected by the guide hole highlighted with a dotted line (i.e. the metalized guide hole 100c), thereby distributing the same signal on the two opposite faces FA and FB of the guide 40 (as discussed above, there could be obviously even more than one guide hole for the connection between the various metallization portions) .

[0088] In another embodiment illustrated in figure 3, in addition or as an alternative to what has been seen above, the conductive connection elements comprise at least one conductive track 40t (also indicated as conductive via) which extends from the first face FA to the second face FB of the guide 40 and is connected both to the first portion 30a and to the second portion 30b.

[0089] The first portion 30a and the second portion 30b are thereby electrically connected to each other by the above conductive track 40t.

[0090] Although figure 3 shows for simplicity only one conductive track 40t for the connection between the first portion 30a and the second portion 30b, several conductive tracks can be provided. In this example as well, some probes (in particular the probes on the left) are short-circuited by the upper first portion 30a, while other probes (in particular the probes on the right) are short-circuited by the lower second portion 30b, but they are still dedicated to carry the same signal (for example a same power supply) .

[0091] According to another embodiment of the present invention, the conductive connection elements comprise at least one contact probe 10, which thus acts as an electrical connection between the first portion 30a and the second portion 30b. In other words, the first portion 30a and the second portion 30b are electrically connected to each other by the contact probe itself, which carries the signal from the first portion 30a to the second portion 30b with which it is in contact (for example a sliding contact). The contact probe 10 is thus a probe of the group of probes housed in the group of holes 40hg, in electrical connection with the conductive portion 30 and it can be physically equal to the other contact probes of the domain.

[0092] In this case, the wall of the guide hole can also be non-metalized, or only partially metalized, even if the present invention is not limited to this aspect.

[0093] As mentioned above, the conductive portion 30 can be configured to carry a given power supply, thereby forming a given power supply domain, or it can be configured to carry a ground signal, thereby forming a given ground domain, without limiting the scope of the present invention.

[0094] Generally, as illustrated in figures 4A and 4B, in addition to the conductive portion 30, the probe head 100 comprises at least one further conductive portion (indicated with the reference 30bis) configured to include and electrically connect a further group of the guide holes which houses further contact probes which are thus short-circuited by this further conductive portion 30bis, the contact probes 10 and the further contact probes being connectable with respective different sources for carrying a respective different type of signal. For example, a conductive portion can be dedicated to a power signal and the other conductive portion can be dedicated to a ground signal or to another power signal, as detailed below.

[0095] In general, a plurality of conductive portions can be provided, each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions, as well as there can also be conductive portions configured to carry ground signals and / or operative signals from / to the device under test DUT, without limiting the scope of the present invention, wherein these conductive portions can be distributed on both faces of the guide in the above-illustrated mode.

[0096] In this case, as mentioned above, the conductive portions on a face of the guide 40 are separated from each other by at least one non-conductive area or zone (generically indicated with the reference 31) so as not to allow the electrical connection therebetween. In an embodiment, there can also be a dielectric coating portion which covers the non-conductive area 31.

[0097] As noted for the conductive portion 30, the further conductive portion 30bis (as well as all the other possible conductive portions) can also be divided into at least a first portion 30abis and a second portion 30bbis (for example, it can continue on the opposite face of the guide), due to the great versatility of the present invention. In the example shown in figure 4A and 4B, the first portion 30abis and the second portion 30bbis are connected by two metalized holes.

[0098] Obviously all the figures shown are only indicative and do not limit in any way the present invention, and the real configurations might be different and much more complex.

[0099] An embodiment in which the conductive portion 30 extends on a same guide (i.e. the guide 40) has been illustrated so far. However, according to the present invention, it is also possible to provide an alternative solution to the same problem in which there is at least a first guide (always indicated with the reference 40) provided with first guide holes 40h for housing at least a first portion of the contact probes 10, and a second guide 50 provided with second guide holes 50h for housing at least a second portion of the contact probes 10 and separated from the first guide 40 by a gap G (for example an air gap) .

[0100] The first guide 40 can be a lower guide while the second guide 50 can be an intermediate guide or also an upper guide (as well as a combination of all these embodiments is possible), without limiting in any way the scope of the present invention.

[0101] In this case too there is at least one conductive portion 30 which includes at least one group of the guide holes and which is configured to contact and short-circuit a corresponding group of contact probes that are housed in said group of the guide holes and are intended to carry a given same type of signal. In this case, as it will be clear from the following description, the reference lOOhg will be used to indicate the group of the guide holes which are inside the conductive portion 30, which is distributed on different guides and thus includes guide holes of different guides.

[0102] In particular, as illustrated in figure 5, advantageously according to the present invention, the conductive portion 30 is divided into at least a first portion 30a formed at the first guide 40 and a second portion 30b formed at the second guide 50 and electrically connected to the first portion 30a by means of conductive connection elements.

[0103] In this case, the group lOOhg of holes thus comprises guide holes of different guides, in particular the guide holes 40h and 50h which respectively belong to the guides 40 and 50, these holes thus belonging to the same group, and house contact probes which are all dedicated to carry a same signal (for example a same power supply signal) .

[0104] According to a preferred embodiment, the conductive connection elements between the metallization portions (i.e., between the first portion and the second portion) comprise at least one contact probe 10 of the plurality of contact probes, which thereby acts as an electrical connection between the first portion 30a and the second portion 30b, extending between the first guide 40 and the second guide 50 and being housed in the respective guide holes. The contact probe 10 is thus a contact probe housed in the group lOOhg, in electrical connection with the conductive portion 30 (for example by means of sliding contact).

[0105] The first portion 30a and the second portion 30b are thereby electrically connected to each other by the contact probe itself which extends between the two guides 40 and 50.

[0106] For convenience of description, the contact probe 10 which acts as a connection element is also indicated with the reference 100c, so as to emphasize its specific function of electrical connection, although generally it can be structurally identical to the other contact probes of the group of probes housed in the holes of the group lOOhg and it carries the same type of signal.

[0107] As also illustrated above, the wall of the guide hole can also be nonmetallized, or only partially metallized to facilitate the electrical connection or completely metallized without limiting the present invention.

[0108] Obviously, although for simplicity only one contact probe 10 (or 100c) for the connection between the first portion 30a and the second portion 30b is shown in figure 5, more than one contact probe can be used for electrically connecting to each other the various portions into which the conductive portion 30 is divided, for example adjacent probes can be used.

[0109] Less preferred solutions can also be provided, for example solutions in which there are conductive wires between the first portion 30a and the second portion 30b, in addition or as an alternative to the abovediscussed connection contact probe(s). As illustrated in the example of figure 5, the first portion 30a and the second portion 30b can be formed on respective faces of the first guide 40 and the second guide 50, for example on the respective upper faces FA and FC.

[0110] Obviously, exactly the same considerations made for the previous embodiment in relation to the type and number of conductive portions also apply in this embodiment. For example, the conductive portion 30 can be a power or ground metallization, as well as there can be several metallizations which short-circuit further contact probes (for example for different power domains), each one possibly distributed on the different guides in accordance with the present invention.

[0111] Finally, in an alternative embodiment of the present invention (not illustrated in the figures), the contact probes 10 can be in the form of pogo pins. In this case, the body lOp comprises a casing and an elastic element arranged in the casing, which defines a first surface and a second surface, these surfaces forming suitable shoulders for abutting against the guide, provided with at least one conductive portion as described above. In this case, the probe head 100 can also comprise an upper guide separated from the lower guide by a gap, possibly comprising one or more conductive portions as well. Suitably, at least one of the above surfaces of the pogo pin is adapted to abut onto the guide (in this case generally on both guides), the electrical connection between the pogo pins and the metallization being in this case a pressing contact by means of said first and / or second surface, as well as the pogo pin can be provided with an element, such as a clip for example, to perform said connection, without limiting the present invention. Then, all the considerations made above in relation to the division of the conductive portion into the first portion and the second portion apply also to this embodiment.

[0112] In conclusion, the present invention thus allows the technical problem to be successfully overcome, providing the above probe head and solving all the drawbacks of the prior art. Advantageously according to the present invention, there is a greater freedom in the design and arrangement of the conductive portions on the guide, since it is no longer necessary to arrange them entirely on a single face of the guide but, if desired, they can continue on the opposite face or on another guide of the probe head.

[0113] The constraints that characterize the known solutions are thereby loosened; in fact, very frequently, based on the device under test, an alternation of probes for different signals is present, which can complicate the layout of the metallizations and which is solved with the present invention, which guarantees a much larger space for the arrangement of said metallizations.

[0114] Obviously, in order to meet contingent and specific requirements, a person skilled in the art can bring to the above-described probe head several modifications and variants, all falling within the scope of protection of the invention as defined by the following claims.

Claims

CLAIMS1. A probe head (100) for testing a device under test (DUT), said probe head (100) comprising: a plurality of contact probes (10) comprising a body ( lOp) extended between a first end portion (10a) and a second end portion (10b) which are adapted to contact respective contact pads; at least one guide (40) comprising guide holes (40h) for housing at least one portion of the contact probes (10); and at least one conductive portion (30) which includes at least one group (40hg) of the guide holes (40h) and which is configured to contact and short-circuit a corresponding group (10g) of contact probes that are housed in said group (40hg) of the guide holes and are intended to carry a given same type of signal, wherein the conductive portion (30) is divided into at least a first portion (30a) formed on a first face (FA) of the guide (40) and a second portion (30b) formed on a second face (FB) of the guide (40), said second face (FB) being opposite to the first face (FA), said second portion (30b) being electrically connected to the first portion (30a) by means of conductive connection elements.

2. The probe head (100) according to claim 1, wherein the conductive connection elements comprise at least one wall (40hw) of at least one guide hole (40h), said wall (40hw) being coated with a conductive material forming a connection between the first portion (30a) and the second portion (30b).

3. The probe head (100) according to claim 1 or 2, wherein the conductive connection elements comprise at least one conductive track (40t) which extends from the first face (FA) to the second face (FB) of the guide (40) and is connected both to the first portion (30a) and to the second portion (30b).

4. The probe head (100) according to any one of the preceding claims, wherein the conductive connection elements comprise at least one contact probe (10) of the plurality of contact probes, said contact probe (10) acting as an electrical connection between the first portion (30a) and the second portion (30b).

5. The probe head (100) according to any one of the preceding claims, wherein the conductive portion (30) is configured to carry a given power supply signal, thereby forming a given power supply domain, or wherein the conductive portion (30) is configured to carry a ground signal, thereby forming a given ground domain.

6. The probe head (100) according to any one of the preceding claims, comprising, in addition to the conductive portion (30), at least one further conductive portion (30bis) which includes a further group of the guide holes (40h) and which is configured to contact and short-circuit a corresponding group of further contact probes housed in said further group of the guide holes, the contact probes (10) and the further contact probes being connectable with respective different sources for carrying a respective different type of signal.

7. The probe head (100) according to claim 6, wherein the further conductive portion (30bis) is divided into at least a first portion (30abis) formed on the first face (FA) of the guide (40) and a second portion (30bbis) formed on the second face (FB) of the guide (40) which is opposite to the first face (FA), said second portion (30bbis) being electrically connected to the first portion (30abis).

8. The probe head (100) according to claim 6 or 7, comprising a plurality of conductive portions each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions.

9. The probe head (100) according to claim 8, further comprising conductive portions configured to carry ground signals and / or operativesignals from / to the device under test (DUT).

10. The probe head (100) according to any one of claims 6 to 9, wherein the conductive portions on a face of the guide (40) are separated from each other by at least one non-conductive area (31) so as not to allow the electrical connection therebetween, and wherein said at least one guide (40) optionally comprises at least one dielectric coating portion which covers said at least one non-conductive area (31).

11. The probe head (100) according to any one of the preceding claims, wherein said guide (40) is a lower guide or an intermediate guide of the probe head (100).

12. The probe head (100) according to any one of the preceding claims, wherein the contact probes (10) are in the form of contact probes of the buckling beam type wherein the body ( lOp) has a deformation.

13. A probe head (100) for testing a device under test (DUT), said probe head (100) comprising: a plurality of contact probes (10) comprising a body ( lOp) extended between a first end portion (10a) and a second end portion (10b) which are adapted to contact respective contact pads; a first guide (40) comprising first guide holes (40h) for housing at least a first portion of the contact probes (10); a second guide (50) comprising second guide holes (50h) for housing at least a second portion of the contact probes (10) and separated from the first guide (40) by a gap (G); and at least one conductive portion (30) which includes at least one group (lOOhg) of the guide holes (40h, 50h) and which is configured to contact and short-circuit a corresponding group (10g) of contact probes that are housed in said group (lOOhg) of the guide holes and are intended to carry a given same type of signal,wherein the conductive portion (30) is divided into at least a first portion (30a) formed at the first guide (40) and a second portion (30b) formed at the second guide (50) and electrically connected to the first portion (30a) by means of conductive connection elements.

14. The probe head (100) according to claim 13, wherein the conductive connection elements comprise at least one contact probe (10) of the plurality of contact probes, said contact probe (10) thereby acting as an electrical connection between the first portion (30a) and the second portion (30b).

15. The probe head (100) according to claim 13 or 14, wherein the first portion (30a) and the second portion (30b) are formed on respective faces of the first guide (40) and the second guide (50).

16. The probe head (100) according to any one of claims 13 to 15, wherein the conductive portion (30) is configured to carry a given power supply signal, thereby forming a given power supply domain, or wherein the conductive portion (30) is configured to carry a ground signal, thereby forming a given ground domain.

17. The probe head (100) according to any one of claims 13 to 16, comprising, in addition to the conductive portion (30), at least one further conductive portion (30bis) formed on a same face of one of the first guide (40) and the second guide (50), said further conductive portion (30bis) including a further group of the guide holes (40h, 50h) and being configured to contact and short-circuit a corresponding group of further contact probes housed in said further group of the guide holes, the contact probes (10) and the further contact probes being connectable with respective different sources for carrying a respective different type of signal.

18. The probe head (100) according to claim 17, wherein the further conductive portion (30bis) is divided into at least a first portion (30abis) formed at the first guide (40) and a second portion (30bbis) formed at thesecond guide (50) and electrically connected to the first portion (30abis).

19. The probe head (100) according to claim 17 or 18, comprising a plurality of conductive portions each one dedicated to a respective power supply, which is different from the power supplies of the other conductive portions.

20. The probe head (100) according to claim 19, further comprising conductive portions configured to carry ground signals and / or operative signals from / to the device under test (DUT).

21. The probe head (100) according to any one of claims 17 to 20, wherein the conductive portions on a same face of the guide are separated from each other by at least one non-conductive area (31) so as not to allow the electrical connection therebetween.

22. The probe head (100) according to any one of claims 13 to 21, wherein the contact probes (10) are in the form of contact probes of the buckling beam type wherein the body ( lOp) has a deformation.

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