Probe head with improved contact probe

Abstract

A probe head (100) for testing electronic devices is described, the probe head (100) having at least one contact probe (10) having a body (10') extending along a longitudinal axis (HH) between a first end (10a) and a second end (10b), the ends (10a, 10b) configured to contact respective contact pads (20a, 30b), and at least one guide hole (40h) configured to accommodate at least a portion of the contact probe (10). The contact probe (10) has at least one intermediate section (10s) positioned between the first end (10a) and the second end (10b) and elastically flexible along at least the longitudinal axis (HH).

Description

Technical Field

[0001] The present invention relates to a probe head configured to perform tests on electronic devices integrated on a semiconductor wafer, such as high-frequency devices. The following description is provided with reference to its application field only for the purpose of simplifying the description of the present invention.

Background Art

[0002] As is well known, a probe head is essentially a device configured such that a plurality of contact pads, i.e., a plurality of pads of a fine structure, particularly an electronic device integrated on a semiconductor wafer, are electrically contacted to corresponding channels of a test apparatus that performs a functional test thereon.

[0003] Tests performed on integrated circuits are particularly useful for detecting and isolating defective circuits at an early stage of the manufacturing process. Therefore, typically, a probe head is used to test these circuits before the circuits integrated on the wafer are cut and assembled into chip encapsulation packages.

[0004] A probe head essentially includes a plurality of contact probes housed in a pair of supports or guides that are substantially plate-shaped and parallel to each other. These plate-shaped supports are provided with appropriate guide holes and are spaced apart from each other to leave a free region or gap for the movement and possible deformation of the contact probes. The contact probes are usually formed of wires of a special alloy having good electrical and mechanical properties.

[0005] A contact probe usually extends between a first end intended to contact a pad of a device under test and a second end intended to contact a space transformer or a printed circuit board (PCB).

[0006] The correct operation of a probe head is fundamentally related to two parameters: the vertical movement (or overtravel or overdrive) of the contact probe, and the horizontal movement (or scrub) of the contact tip of these probes on the pads during contact with the device under test. All of these characteristics must be evaluated and calibrated during the manufacturing of the probe head, and a good electrical connection between the contact probe and the device under test must always be ensured. Therefore, ensuring proper contact of the contact probe with various pads during testing is of particular importance.

[0007] Generally, the maximum overtravel of a contact probe is equal to the dimension of the probe portion that protrudes relative to the lower guide. This protrusion retracts into the lower guide upon contact with the device under test due to bending or deformation of the probe itself. However, the height of this protrusion is limited by the mechanical resistance of the probe and is usually low. It should also be added that the maximum overtravel of a probe is only theoretically achievable, as problems related to probe interlocking and deformation arise even at much smaller overtravel levels.

[0008] According to some known solutions, pre-deformed contact probes are manufactured, but these solutions have various drawbacks, such as difficulty in maintenance, the need for special means to hold the probe, and of course, interlocking problems during testing. Another problem with these known solutions is related to contact pad wear caused by the probe itself.

[0009] Furthermore, in the past, extremely short probes were manufactured to ensure optimal performance even for high-frequency testing. In this case, probe length becomes a significant issue, particularly due to the self-inductance phenomenon. However, shortening the probe body significantly increases the rigidity of the probe itself, increasing the force exerted on various pads by each contact tip. This can lead to pad failure, potentially causing irreparable damage to the device under test. The increased rigidity of the contact probe due to its shortened length also increases the risk of the probe itself breaking. Therefore, even in this case, a contact probe that can ensure improved contact during testing is necessary.

[0010] The technical problem of the present invention is to devise a probe head having structural and functional features that can overcome the limitations and drawbacks that still affect known solutions, and it is particularly necessary that such a probe head allows for ensuring optimal contact with the contact pad during testing, for example, by improved control of the probe's contact force, while eliminating the risk of interlocking the probes and / or damaging them. [Overview of the project]

[0011] The underlying solution idea of ​​the present invention is to manufacture a probe head in which the contact probe undergoes elastic deformation during testing, preferably mainly in the longitudinal direction (though not necessarily so). In particular, the contact probe has at least one elastically flexible intermediate section, so that the contact probe functions substantially as an elastic spring, and the aforementioned elastically flexible intermediate section is structured and made to a size that ensures optimal contact force and proper stability of the contact probe.

[0012] It is also possible to configure the elastically flexible intermediate section to generate twisting or lateral scrubbing (generally lateral movement) on the pad. In fact, in some embodiments, the elastically flexible intermediate section can be provided with elastically weaker and elastically stronger portions, as well as a helical shape.

[0013] Based on the idea of ​​this solution, the above technical problem is solved by the following probe head for testing electronic devices, the probe head comprising: at least one contact probe having a body extending along a longitudinal axis between a first end and a second end, the ends of which are configured to contact the respective contact pads; and at least one guide having at least one guide hole configured to accommodate at least a portion of the contact probe, wherein the contact probe comprises at least one intermediate section positioned between the first end and the second end and being elastically flexible (or pliable) at least along the longitudinal axis, the elastically flexible intermediate section being configured (made and formed to a size that determines the contact force exerted on the contact pad by the contact probe) (e.g., strength and / or direction), and the contact probe functions as a spring.

[0014] More specifically, the present invention comprises the following additional and optional features, individually or in combination as appropriate.

[0015] According to one aspect of the present invention, the length measured along the longitudinal axis of the contact probe can be less than 2000 μm, preferably less than 1000 μm, and more preferably 800 μm or less.

[0016] According to one aspect of the present invention, the guide may comprise a first guide portion and a second guide portion, the second guide portion being initially manufactured structurally independently of the first guide portion and then associated with it.

[0017] According to one aspect of the present invention, the second guide portion can be attached to the contact probe by overlapping it with the first guide portion.

[0018] According to one aspect of the present invention, the second guide portion can be connected to the first guide portion by mounting means.

[0019] According to one aspect of the present invention, an elastically flexible intermediate section can be obtained by interlocking engravings formed on the body of the contact probe, wherein the interlocking engravings are configured such that the contact probe functions as an elastic spring.

[0020] According to one aspect of the present invention, the elastically flexible intermediate section can be made serrated.

[0021] According to one aspect of the present invention, the elastically flexible intermediate section can be structured as a plurality of polygonal elastic elements that are connected to one another along the longitudinal axis of the contact probe, such as a series of interconnected hexagons.

[0022] According to one aspect of the present invention, the elastically flexible intermediate section can be structured as a plurality of elliptical elastic elements that are adjacent to one another along the longitudinal axis of the contact probe.

[0023] According to one aspect of the present invention, the contact probe may have a non-circular cross-section, preferably a rectangular cross-section, more preferably a rectangular cross-section having a first side having a length of 30 μm and a second side having a length of 70 μm.

[0024] According to one aspect of the present invention, the contact probe can include a plurality of elastically flexible intermediate sections separated from each other by portions of the probe body, and the elastically flexible intermediate sections are consecutive to each other along the longitudinal axis of the contact probe.

[0025] According to one aspect of the present invention, the elastically flexible intermediate sections can be arranged in guides so as to be at least partially received in the guide holes.

[0026] According to one aspect of the present invention, the probe head can include a lower guide and an upper guide separated from each other by a gap, and the lower guide and the upper guide include respective lower guide holes and upper guide holes for accommodating the contact probe.

[0027] According to one aspect of the present invention, the elastically flexible intermediate sections can be arranged in the gap between the lower guide and the upper guide.

[0028] According to one aspect of the present invention, the lower guide holes and the upper guide holes can be misaligned with respect to each other. That is, the holes associated with the same probe are not on the same axis parallel to the longitudinal axis of the contact probe, i.e., the vertical axis.

[0029] According to one aspect of the present invention, the elastically flexible intermediate sections can extend along the longitudinal axis with a length of 1000 μm to 80 μm.

[0030] According to one aspect of the present invention, the elastically flexible intermediate sections can extend with a pitch of 100 μm to 5 μm.

[0031] According to one aspect of the present invention, the contact probe can be made of a material selected from Pd, PdCo, Ni, NiCo, Au, Pt, Ag, Rh, or a combination thereof.

[0032] According to one aspect of the present invention, at least one guide hole may comprise at least one wall inclined with respect to the longitudinal axis of the contact probe, thereby giving the guide hole a non-linear cross-sectional shape.

[0033] According to one aspect of the present invention, the guide hole may be provided with a pair of inclined opposing walls.

[0034] According to one aspect of the present invention, the elastically flexible intermediate section can be configured such that the contact force exerted on the contact pad by the contact probe is substantially directed along the longitudinal axis of the probe, with substantially zero lateral component.

[0035] Additionally or alternatively, the contact force may also have a lateral component or, more generally, a non-longitudinal component. In other words, according to one aspect of the present invention, the elastically flexible intermediate section can be configured such that the contact force exerted on the contact pad by the contact probe has both a longitudinal / axial component and a component along an axis different from the longitudinal axis, such as a lateral component, and thus deformation having components along the longitudinal direction and along different directions (e.g., lateral, torsional, etc.) corresponds thereto.

[0036] According to one aspect of the present invention, the elastically flexible intermediate section may have an elastically weaker wall on the opposite side, thereby causing lateral movement during overtravel.

[0037] According to one aspect of the present invention, the elastically flexible intermediate section may be equipped with an elastic deformation mechanism (also called a further elastic element) comprising arms having different elasticities (for example, one arm may be less elastic than the other), so that the elastic deformation of the section occurs not only along the longitudinal direction but also along other directions, for example, causing a scrubbing motion of the first end of the contact probe on the pad of the device under test.

[0038] According to one aspect of the present invention, an elastically flexible intermediate section can be configured to twist during contact with the device under test and, therefore, during overtravel.

[0039] According to one aspect of the present invention, the second end of the contact probe may include an arm that protrudes laterally from its body and is configured to contact a contact pad of an interface card (such as a PCB), wherein the arm is configured to offset the contact point between the contact probe and the contact pad of the interface card with respect to the longitudinal axis of the contact probe.

[0040] According to one aspect of the present invention, the probe head may comprise a plurality of contact probes having arms of different lengths, the lengths of which are measured along their longitudinal deployment direction.

[0041] According to one aspect of the present invention, the first end of the contact probe may include a high-hardness material such as rhodium.

[0042] According to one aspect of the present invention, the probe head may further comprise a conductive portion formed on a guide, the conductive portion comprising at least one group of the guide holes, and configured to contact and short-circuit a corresponding group of contact probes housed in the group of holes and intended to transmit a predetermined type of signal, thereby forming a predetermined conductive domain, wherein at least a portion of the contact probes is in contact with the conductive portion.

[0043] According to one aspect of the present invention, the elastically flexible intermediate section can be structured as a plurality of interconnected elastic elements that are adjacent to one another along the longitudinal axis of the contact probe, each of which is configured to be compressed by the pressure generated during testing of the device under test. Each of the elastic elements is also configured such that, during the compression, its dimension along the longitudinal axis of the contact probe is reduced and its lateral dimension (i.e., its dimension along an axis perpendicular to the longitudinal axis) is increased, and these elastic elements have an elongated shape along the longitudinal axis.

[0044] According to one aspect of the present invention, at least one of the above-mentioned elastic elements can be configured to contact a conductive portion via its sidewall as its lateral dimension increases during testing of the device under test.

[0045] According to one aspect of the present invention, the contact probe may include a stopping means formed on its body, configured to mechanically contact at least a portion of a guide to cause the contact probe to be retained within the probe head.

[0046] According to one aspect of the present invention, the stopping means may include a stopper having a lateral extension that defines at least one shoulder portion configured to abut against the surface of the guide, the surface being opposite to the surface of the guide facing the device under test (overall, the stopper bonded to the probe body may have a lateral extension larger than that of the guide hole in order to properly hold the contact probe).

[0047] Additionally or alternatively, the stopping means may include at least one clip configured to mechanically interfere with a guide hole and to contact the corresponding wall of the guide hole, the clip protruding from the body of the contact probe and configured to elastically deform while in contact with the wall of the guide hole, thereby causing the mechanical interference with the guide hole to retain the contact probe.

[0048] According to one aspect of the present invention, the contact probe may include a stopping means, in particular an elastic portion disposed between a stopper and its second end, the elastic portion being configured to be pre-compressed in a stationary state after the assembly of the probe head, and to exert a pre-loading force at least along the longitudinal axis when pre-compressed.

[0049] According to one aspect of the present invention, an elastically flexible intermediate section can be embedded in a polymer material.

[0050] According to one aspect of the present invention, the guide may comprise a first guide having a first guide hole and a second guide having a second guide hole, wherein an elastically flexible intermediate section is positioned in at least one of the first and second guide holes, and the contact probe further comprises an intermediate stopping means positioned between the first and second guides, wherein the intermediate stopping means is configured to mechanically contact at least a portion of the first and / or second guides in order to hold the contact probe within the probe head.

[0051] According to one aspect of the present invention, the intermediate stopping means may include an intermediate stopper having a lateral extension that defines at least one shoulder portion configured to abut against the surface of the first guide and / or the second guide (as described above, the stopper bonded to the probe body as a whole may have a lateral extension larger than that of the guide hole in order to properly hold the contact probe).

[0052] According to one aspect of the present invention, the intermediate stopping means may include a retaining element formed as an elastic hook, which is configured to elastically deform while inserting the contact probe through either a first guide hole or a second guide hole, and while withdrawing the contact probe through the other of the first and second guide holes. The retaining element is configured not to deform when housed between the first and second guides, and is configured to mechanically contact the first and / or second guides to hold the contact probe.

[0053] The features and advantages of the probe head according to the present invention will become apparent from the following description of a typical embodiment shown as a non-limiting example, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0054] [Figure 1] A schematic diagram of a probe head according to the present invention is shown. [Figure 2] The contact probes of probe heads according to various embodiments of the present invention are shown. [Figure 3] A schematic diagram of a probe head according to one embodiment of the present invention, which has two overlapping guide sections, is shown. [Figure 4] A schematic diagram of a probe head according to one embodiment of the present invention, assuming the presence of a lower guide and an upper guide, is shown. [Figure 5] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 6] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 6bis] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 7] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 7bis] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 8] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 8bis] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 9] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 10] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 11] A schematic diagram shows a probe head having a contact probe according to a different embodiment of the present invention, particularly one having a different geometry. [Figure 12] A schematic diagram of a probe head according to one embodiment of the present invention, which assumes the presence of a conductive part for short-circuiting a group of probes, is shown. [Figure 13] The following schematic examples illustrate embodiments of the present invention in which the conductive portion is arranged in various ways on the guide of the probe head. [Figure 14] The following schematic examples illustrate embodiments of the present invention in which the conductive portion is arranged in various ways on the guide of the probe head. [Figure 15] The following schematic examples illustrate embodiments of the present invention in which the conductive portion is arranged in various ways on the guide of the probe head. [Figure 16A] A schematic probe head according to one embodiment of the present invention is shown. [Figure 16B] A schematic probe head according to one embodiment of the present invention is shown. [Figure 17A] A schematic probe head according to one embodiment of the present invention is shown. [Figure 17B] A schematic probe head according to one embodiment of the present invention is shown. [Figure 18] A schematic diagram of a probe head according to one embodiment of the present invention is shown, wherein the contact probe is equipped with a stopping mechanism in the form of a stopper. [Figure 19] A schematic diagram of a probe head according to one embodiment of the present invention is shown, in which the contact probe is equipped with a clip-shaped stopping mechanism. [Figure 20] A combination of the embodiments shown in Figures 18 and 19 is presented. [Figure 21A] A schematic diagram of a probe head according to one embodiment of the present invention is shown, in which the stopper contacts the conductive part. [Figure 21B] A schematic diagram of a probe head according to one embodiment in which the clip is in contact with a conductive part is shown. [Figure 22] A schematic diagram of a probe head according to one embodiment of the present invention, which has a non-linear guide hole, is shown. [Figure 23] A schematic diagram of a probe head according to one embodiment of the present invention is shown, which has multiple elastically flexible intermediate sections separated by a more rigid portion of the probe body. [Figure 24] A schematic diagram of a probe head according to one embodiment of the present invention, which has a preloaded elastic portion, is shown. [Figure 25] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 26] A schematic diagram of a probe head according to one embodiment is shown, in which an elastically flexible intermediate section is embedded in a polymer material. [Figure 26bis] A schematic diagram of a probe head according to one embodiment is shown, in which an elastically flexible intermediate section is embedded in a polymer material. [Figure 27A] A schematic diagram of a probe head according to one embodiment of the present invention is shown, which has a non-linear, elastically flexible intermediate section. [Figure 27B] A schematic diagram of a probe head according to one embodiment of the present invention is shown, which has a non-linear, elastically flexible intermediate section. [Figure 28] A schematic diagram of a probe head according to one embodiment of the present invention is shown, which has a pair of intermediate guides that can be linked together. [Figure 29] A schematic probe head according to one embodiment of the present invention is shown. [Figure 30] A schematic diagram of a probe head according to one embodiment is shown, in which an intermediate stopper positioned between two intermediate guides has multiple protrusions. [Figure 31] A schematic diagram of a probe head according to one embodiment of the present invention, assuming the presence of an additional upper stopper, is shown. [Figure 32] A schematic probe head according to one embodiment of the present invention is shown. [Figure 33] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 34] A schematic diagram shows a probe head according to one embodiment of the present invention, which is provided with two separate intermediate guides and two elastic sections. [Figure 35] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 36] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 37] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 38] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 39] A schematic diagram of a probe head according to a further embodiment is shown, in which the end of the contact probe has a laterally projecting arm. [Figure 39bis] A schematic diagram of a probe head according to a further embodiment is shown, in which the end of the contact probe has a laterally projecting arm. [Figure 40]A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 40bis] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 41] A schematic diagram of a probe head according to a further embodiment of the present invention is shown. [Figure 42] Various embodiments of the present invention are shown. [Figure 43] Various embodiments of the present invention are shown. [Figure 44] Various embodiments of the present invention are shown. [Figure 45] Various embodiments of the present invention are shown. [Figure 46] Various embodiments of the present invention are shown. [Modes for carrying out the invention]

[0055] Referring to the drawings, a probe head for testing an electronic device manufactured according to the present invention is schematically shown overall at 100.

[0056] It should be noted that the figures are schematic diagrams and are not drawn to scale, but rather to highlight important features of the invention. Furthermore, various elements are schematically depicted in the figures, and their shapes can be modified depending on the desired application. Also, it should be noted that the same reference numeral in the figures refers to the same element in terms of shape or function. Finally, certain means described in relation to an embodiment shown in one figure can also be used in other embodiments shown in other figures.

[0057] Furthermore, please note that unless explicitly stated otherwise, the steps of the described process can be reversed as needed.

[0058] The probe head 100 is configured to connect (directly or more preferably indirectly by a space transformer and / or PCB) to equipment (not shown) for performing tests on electronic devices integrated on the semiconductor wafer 20, such as (but not necessarily) high-frequency devices.

[0059] In the context of the present invention, it should be noted that the term “probe head” is used to describe a test apparatus, without being limited by the presence or absence of specific components, in addition to being defined by the appended claims. Therefore, generally, the term refers to a set of components that can be associated with further components for checking devices integrated on the semiconductor wafer 20 described above, and thus generally refers to a system for measuring electronic devices.

[0060] Referring to the cross-sectional view in Figure 1, the probe head 100 first comprises a plurality of contact probes 10 intended to electrically contact the device under test, which is integrated on the semiconductor wafer 20, with the test apparatus.

[0061] To accommodate the contact probe 10, the probe head 100 includes at least one guide 40 having a guide hole 40h inside which the contact probe is housed. Thus, the guide 40, together with its guide hole 40h, is capable of housing, in particular, at least a portion of the contact probe 10, in a slidable manner.

[0062] Each contact probe 10 comprises a probe body 10' extending along a longitudinal axis (indicated by the reference numeral HH) between a first end 10a and a second end 10b, and these ends are configured to contact their respective pads or contact pads. For example, the first end 10a (also called a contact tip and referred to in this art as a "plunger") is configured to contact a pad 20a of a device under test integrated on a semiconductor wafer 20, while the second opposite end 10b (also called a contact head) is configured to contact a pad 30b of a space transformer or printed circuit board (PCB) that can be associated with a probe head 100, and such components are collectively identified by the reference numeral 30 and commonly defined as an "interface card". Thus, generally, the term "end" means the terminal portion of the contact probe 10, which comprises the point of contact of the probe with the pad.

[0063] In one embodiment (as illustrated in a simple example), pad 30b is a pad on a PCB board, but the use of an interposer positioned between the PCB and the probe's contact head is obviously not ruled out.

[0064] Although the ends 10a and 10b in the attached drawings are shown to end in a pointed shape, they are clearly not limited to this and can have any shape as needed and / or in accordance with the circumstances.

[0065] Furthermore, while the diagram shows a single contact probe 10 for simplicity, please note that the probe head 100 can be equipped with any number of contact probes depending on the application.

[0066] In the embodiment shown in Figure 1, a frame F is also provided that functions as a structural support for the probe head 100 as a whole, and is positioned particularly between the guide 40 and the PCB 30. This frame F is omitted in subsequent figures solely for the sake of simplicity in illustration.

[0067] Ideally, to enable high-performance high-frequency testing, the contact probe 10 is shortened in length, particularly to less than 2000 μm, preferably less than 1000 μm, and even more preferably less than 800 μm, and this length is measured along the longitudinal axis HH of the probe. This appropriately reduces the self-induction phenomenon and ensures effective testing even at very high frequencies in the radio frequency range.

[0068] Advantageously, according to the present invention, in order to ensure proper contact with the pads 20a and 30b, and in particular to ensure proper control of the contact force, the contact probe 10 comprises at least one intermediate section 10s positioned between the first end 10a and the second end 10b and being elastically flexible (or pliable) at least along the longitudinal axis HH. The elastically flexible intermediate section 10s (hereinafter also referred to as the “elastic section” of the probe) is configured to determine the contact force FC (particularly its direction and / or strength) exerted on the pads 20a and / or 30b by the contact probe 10. That is, the contact force FC can be controlled by the structure (shape / size) of the elastically flexible intermediate section 10s, and the probe functions as a spring.

[0069] In particular, in a preferred embodiment, the elastically flexible intermediate section 10s is appropriately configured such that the contact probe 10 exerts a contact force FC substantially oriented along the longitudinal axis HH on the contact pads 20a and 30b, but in other embodiments, forces from other elements may also be present. (For example, it is possible to configure the elastically flexible intermediate section to generate torsion or lateral scrubbing on the pads, such as generating scrubbing motion, and in fact, in some embodiments, it is possible to provide elastically weaker and elastically stronger portions of the elastically flexible intermediate section 10s, and similarly, it is possible to provide the elastically flexible intermediate section 10s with a not-so-symmetrical helical shape.)

[0070] The contact force FC (with a negligible lateral component) is primarily located in the longitudinal direction, which reduces the risk of interlocking of the contact probe 10.

[0071] As described above, according to embodiments of the present invention, the contact force FC can also have a lateral component. That is, the elastically flexible intermediate section 10s can be configured such that the contact force FC exerted on the contact pad by the contact probe 10 has both a longitudinal / axial component and a lateral component, for example, to cause scrubbing of the contact tip.

[0072] In one embodiment of the present invention, the elastically flexible intermediate section 10s may have an elastically weaker wall on the opposite side, thereby causing lateral movement during overtravel.

[0073] According to one embodiment of the present invention, the elastically flexible intermediate section 10s may be equipped with an elastic deformation mechanism (also called a further elastic element, as described later in relation to Figure 11) having arms having different elasticity (for example, one arm may be more elastically weaker than the other arm), as a result, the elastic deformation of the section may occur not only along the longitudinal direction but also along other directions, for example, causing a scrubbing motion of the first end of the contact probe on the pad of the device under test.

[0074] According to one aspect of the present invention, the elastically flexible intermediate section 10s may also be configured to twist during contact with the device under test and therefore during overtravel.

[0075] In non-limiting embodiments of the present invention, the elastically flexible intermediate section 10s can be obtained by interlocking engravings or notches 10i formed on the body 10' of the contact probe 10, wherein the interlocking engravings or notches 10i are configured such that the contact probe 10 functions substantially as an elastic spring. Thus, the substantially spring-like elastically flexible intermediate section 10s can be formed, for example, by removing some material, in which case the notches 10i are made symmetrically with respect to the longitudinal axis HH of the contact probe 10 (however, this is not strictly necessary, and an asymmetrical shape with respect to the axis can be provided).

[0076] In general, the present invention is not limited by a specific method for manufacturing the contact probe 10, but is important for the presence of the above-mentioned elastic sections having multiple turns that follow one another along the longitudinal axis HH. Here, the term “turn” in this specification refers to a single elastic element (or elastic sub-part) of a spring that is repeated along the above-mentioned longitudinal axis HH, as detailed below, thereby forming a predetermined elastic pattern without being limited by a specific shape (for example, it does not necessarily represent a circular cross-sectional contour like a helical spring, although such a configuration is clearly possible).

[0077] Therefore, the intermediate section 10s is elastically flexible primarily in the longitudinal direction so as to be compressed along the longitudinal direction during testing of the device under test (however, in other configurations, other directions of deformation of the elastic section, and therefore other directions of contact force FC, can also be provided as described above). In particular, the elastically flexible intermediate section 10s, with a "spring effect" that ensures proper contact force during overdrive and also allows the contact probe 10 to return to its original dimensions when the probe head 100 moves away from the device under test, allows the contact probe 10 to shorten along its longitudinal direction during the normal operation of the probe head 100.

[0078] In the embodiments described above, it should be noted that the contact probe 10 exerts the above-mentioned contact force FC on the pad which is substantially oriented along the longitudinal axis HH, while the component perpendicular to the longitudinal axis HH is substantially zero (or reduced in any case), thereby eliminating the risk of interlocking of the contact probe 10 within the guide hole 40h.

[0079] Preferably, the contact probe 10 has a non-circular cross-section. In a preferred embodiment, the contact probe 10 has a rectangular cross-section, for example, with one side of the rectangle having a length of 30 μm and the other side having a length of 70 μm, but other dimensions are also obviously available.

[0080] Furthermore, it should be noted that the contact probe 10 can be made of composite materials such as layers of Pd, PdCo, ​​Ni, NiCo, Au, Pt, Ag, Rh, etc., without being limited by the specific materials or manufacturing methods used. In general, it is possible to select various materials or combinations of materials (e.g., the materials mentioned above or combinations thereof) depending on the need and / or circumstances.

[0081] The elastically flexible intermediate section 10s extends along the longitudinal axis HH of the contact probe 10 with a length of 1000 μm to 80 μm (preferably about 200 μm) and a pitch of 100 μm to 5 μm (i.e., the stationary distance between the centers of two adjacent turns).

[0082] Figure 2 shows contact probes manufactured according to different designs and pitches of each elastic section, where, for example, the number of loops and the thickness of a single turn vary in the embodiment. Other shapes of the elastically flexible intermediate section 10s are also described below.

[0083] In one embodiment, the elastically flexible intermediate section 10s is formed such that the end of the section is always located on the same side of the contact probe 10.

[0084] The stress on the contact probe 10 can be reduced when an elastically flexible intermediate section 10s having a longer length (for the same total length of the contact probe 10, which is always less than 2000 μm, preferably 800 μm or less, as described above) is manufactured.

[0085] To accommodate the elastically flexible intermediate section 10s, a deep guide hole 40h is formed (for example, having a length greater than 300 μm). As shown in Figure 3, to overcome this problem, instead of using a single guide 40 with a thicker thickness, it is possible to use two or more guides of a thinner thickness that are associated with each other. In other words, in one embodiment, the guide 40 may comprise a first guide portion 40' and a second guide portion 40''. The second guide portion 40'' is initially made structurally independent of the first guide portion 40' and then associated with it, and in particular, it is attached to the contact probe 10 after the contact probe 10 has been introduced into the first guide portion 40'. For example, the second guide portion 40'' may be superimposed on the first guide portion 40', or it may be fixed to it by mounting means, without limiting the present invention to a specific mounting method. This makes the depth of the guide hole of a single guide portion shallower than when using a single guide, and simplifies the formation of the hole.

[0086] A preferred embodiment has been described so far, in which a single guide 40 is provided (for example, its overall thickness is equal to 320 μm, but other thicknesses, such as thicker ones, are obviously possible, and thus the elastic section of the contact probe can be extended), and in this embodiment, the elastically flexible intermediate section 10s is positioned on the guide 40 at a substantially intermediate position so that it is at least partially housed in the guide hole 40h. In other words, an embodiment has been described so far that assumes the presence of a single intermediate guide 40 housing the elastic section of the contact probe 10. This embodiment has the advantage of being easier to assemble and having lower production costs.

[0087] Alternatively, referring to Figure 4, the probe head 100 may be equipped with a lower guide 45l and an upper guide 45u separated from each other by a void or gap G in which an elastically flexible intermediate section 10s is located, thus demonstrating the possibility of increasing the extension of this elastic section. The lower guide 45l and the upper guide 45u are equipped with lower guide holes 45lh and upper guide holes 45uh, respectively, for accommodating the contact probe 10.

[0088] In one embodiment (not shown), the lower guide hole 45lh and the upper guide hole 45uh do not have to be aligned with respect to each other, that is, with respect to a single probe, their centers do not lie on the same longitudinal axis, thereby causing slight deformation of the contact probe 10, which is advantageous for retention and any possible contact with the walls of these holes.

[0089] Next, referring to Figures 5-11, in addition to the standard shapes depicted in Figures 1-4, various shapes are possible for the elastically flexible intermediate section 10s, which is formed by elastic elements that appear as steps in the illustrated cross-sectional view. In these various shapes, a single elastic element (of varying shapes) is defined that is repeated along the longitudinal axis HH so that the different mechanical properties of the contact probe 10 determine the corresponding different elastic patterns.

[0090] For example, among the various possible geometries, the elastically flexible intermediate section 10s can have a shape with a serrated development (Figure 5) or a helical shape, or it can even be structured as a plurality of elastic elements having the shapes of interconnected polygonal elements in a longitudinal cross-section, such as interconnected hexagonal continuum (Figures 6 and 7). The above polygonal elements can have a closed contour (i.e., they can have regions that do not communicate with each other), but this is not required, and embodiments can also be provided in which the various connected polygonal elements have regions that communicate with each other, even if only in short sections.

[0091] Alternatively, the elastically flexible intermediate section 10s may have the shape of interconnected elements, each having an elliptical contour (e.g., oblong), and may be structured as a plurality of elastic elements that are adjacent to one another along the longitudinal axis HH (Figure 8), each of which has an elliptical contour unfolds along an axis of symmetry substantially perpendicular to the longitudinal axis HH of the contact probe 10 and is slightly compressed in the middle.

[0092] More specifically, referring to the geometry described above, the embodiment in Figure 5 allows for increased overdrive of the contact probe 10, while the embodiment in Figure 6 helps maintain the contact probe 10 in a linear configuration, while simultaneously increasing its force and rigidity. On the other hand, the embodiment in Figure 7, in which the slanted sides of the hexagon are replaced with curved sections, helps maintain the contact probe 10 in a linear configuration as in Figure 6, but simultaneously increases its flexibility and decreases its strength. The embodiment in Figure 8 replicates the effect of two joined standard springs, with the aim of increasing the symmetry of the contact probe 10 and maintaining good flexibility.

[0093] Furthermore, the deformations shown in Figures 6bis, 7bis, and 8bis correspond to the geometries of Figures 6, 7, and 8, respectively, except that the single elastic elements in the aforementioned figures are then grouped into interconnected pairs, with each pair being defined by a single closed or single semi-closed contour, for the purpose of further reducing the stiffness of the elastic section and thus the overall stiffness of the contact probe 10.

[0094] Furthermore, referring to the embodiment shown in Figure 9, the elastically flexible intermediate section 10s is formed by a plurality of turns having an asymmetric shape with respect to the longitudinal axis HH, each of which defines a hysteresis curve (for example, when viewed in cross-section). In other words, in this embodiment, the asymmetric shape of the turns is such that, in cross-section, two edges (for example, the larger edge) are offset from each other. This results in the elastic section 10s having a cross-sectional dimension larger than the cross-sectional dimension of the guide hole 40h (as shown in Figure 9), creating friction between the elastic section 10s and the walls of the guide hole 40h, preventing, for example, the contact probe 10 from coming out of the guide 40 during maintenance of the probe head 100, and also ensuring better electrical contact with the possible metallized walls of the guide hole 40h, as will be discussed later. Figure 10 shows a case where the various turns are not aligned along the same axis HH and define a non-linear section, although in other embodiments they can be aligned on the same axis HH.

[0095] Figure 10 shows a further embodiment comprising an elastically flexible intermediate section 10s, in which turns that define a closed curve of hysteresis shape (i.e., elastic elements described in relation to the previous Figure 9) are arranged alternately with standard turns (e.g., standard turns of a helical spring, or standard turns of any other suitable shape) along the longitudinal axis HH of the contact probe 10.

[0096] Furthermore, Figure 11 shows an embodiment in which the standard turn is integrated with an elastic deformation mechanism in an elastically flexible intermediate section 10s, which is shown here as an “additional elastic element 10sm” (spring bounce). In other words, in this embodiment, it is possible to place an additional elastic element 10sm having different deformation characteristics between two elastic elements that deform substantially along the longitudinal axis HH (i.e., perform the standard deformation as described above), and the elastic element 10sm comprises, for example, arms 10sa having different elasticity (in this case, for example, one arm may be less elastic than the other). This occurs not only along the longitudinal direction but also along other directions and helps to modify the deformation characteristics of the above-described elastic section 10s, for example, causing a scrubbing motion of the first end 10a of the contact probe 10 on the pad 20a of the device under test. It is also possible that the elastically flexible intermediate section 10s is formed solely by the above-described additional elastic element 10sm.

[0097] Clearly, the illustrated embodiments are for illustrative purposes only and do not limit the scope of the present invention, but various embodiments can be modified depending on the application and may be combined with each other.

[0098] As will be discussed in more detail later, in another advantageous embodiment, a plurality of elliptical rings are envisioned, in which case, unlike those shown in Figure 8, each of the rings has a length that extends along the longitudinal axis HH of the contact probe 10, in particular to facilitate contact with the wall of the guide hole 40h when these rings are compressed, which is advantageous when there is metallization to short-circuit the group of probes together.

[0099] In this regard, it is well known in the art that the fixed positions of the power and ground signals (for example, due to the layout of the pads of the device under test) and the shape of the probe limit the control of the impedance of the signals inside the probe head, and also limit the control of noise induced in the signal probe by other nearby signals, thereby limiting the frequency performance of the probe head.

[0100] Therefore, in high-frequency applications (especially RF applications), ground probes (and power probes as well) are short-circuited through metallization on the guide, and consequently, probes in the same domain are short-circuited to connect any existing shields, making ground available within the probe head. Also, when devices with different ground / power domains are joined on a PCB, metallization can reduce loop inductance between the power and associated ground.

[0101] For example, consider a case where a single probe contacts a predetermined power supply of the device under test, and that probe is short-circuited to other probes that transmit power from the same power supply unit. In such a case, when the current from this power supply touches the metallization that short-circuits all probes in this domain, it is distributed among all the short-circuited probes, thereby reducing the inductance and equivalent resistance compared to the case where the current to the PCB is limited to a single probe.

[0102] Thus, it is clear that the presence of metallization on the guide, which short-circuits the probe group and creates a common conductive surface, reduces noise and improves the frequency performance of the probe head.

[0103] Similarly, it is also possible to short-circuit signal probes with each other, for example, using loopback technology.

[0104] For this purpose, according to embodiments of the present invention (as shown in Figure 12), the guide 40 of the probe head 100 comprises at least one conductive portion 21, which includes at least one group of holes (indicated by reference numeral 40h') of guide holes 40h, which are configured to electrically connect these holes and to contact and thus short-circuit the corresponding groups of contact probes, which are intended to transmit signals of the same kind, in particular to transmit a predetermined ground or power signal or an operating signal.

[0105] The conductive portion 21 formed on the guide 40, also referred to below as "metallization 21", makes it possible to form a predetermined conductive domain in which at least a portion of the contact probe 10 is in contact with the conductive portion 21.

[0106] In the non-limiting embodiment shown in Figure 12, two contact probes short-circuited by the conductive portion 21 and a contact probe electrically insulated from them are shown, but this is clearly only a schematic example and any number can be provided.

[0107] For example, the contact probes 10, which are short-circuited from each other by the conductive portion 21, can be contact probes intended to transmit a ground signal or contact probes intended to transmit a power signal. In other words, in the probe head 100, the contact probes that are short-circuited from each other by the metallization of the guide 40 and housed in the group 40h' of the guide holes 40h are configured to transmit the same ground signal or power signal, thereby improving the performance of the probe head.

[0108] Furthermore, as mentioned above, the short-circuited probe can also be a contact probe intended to transmit input / output operating signals between the device under test and the test equipment interfaced with the probe head 100, for example, in the case of loopback technology.

[0109] In any case, the conductive portion 21 forms a common conductive surface within the probe head, which is particularly useful in high-frequency testing where a short contact probe 10 can be performed.

[0110] Clearly, the probe head 100 can have any number of conductive parts 21 positioned in any way on the guide, or even embedded within the guide, to transmit any kind of signal. For example, the conductive parts can be formed on the upper surface FB of the guide 40 (as shown in Figure 12) or positioned on its lower surface FA (as shown in Figure 13), and can also be formed inside the guide 40 (i.e., embedded within the guide 40 as depicted in Figure 14).

[0111] Furthermore, it is possible to envision the presence of a first conductive part for short-circuiting the ground probe and a second conductive part for short-circuiting the power probe, located on the opposite side of the guide, and similarly, many other configurations can be provided, such as those described in, for example, the present applicant's international patent application number PCT / EP2017 / 082180.

[0112] As a simple example, as shown in Figure 15, it is possible to provide multiple conductive parts 21' and 21'' corresponding to multiple different conductive domains (e.g., different power domains), and these conductive parts 21' and 21'' are located on the opposite side of the guide 40 (as shown in the non-limiting embodiment of Figure 15) and / or embedded in the guide 40, or even located on the same side of the guide 40.

[0113] The method for manufacturing the conductive part is not limited to a specific method; for example, it can be formed by depositing a conductive material onto a ceramic guide.

[0114] In other words, the present invention is not limited by the number and arrangement of conductive parts, and the number and arrangement of conductive parts can be determined based on necessity and / or circumstances.

[0115] In any case, the important point is that the presence of at least one conductive portion 21 makes it possible to form a common conductive surface, which electrically connects to each other several contact probes (i.e., contact probes 10 housed in groups of holes 40h') that have elastically flexible intermediate sections 10s as described above, and whose length is shortened to improve the overall performance of the probe head 100.

[0116] Furthermore, the conductive portion 21 can cover at least a portion of the wall of the guide hole of group 40h' (generally indicated by 40W, and 40W1 and 40W2 for indicating the opposite wall), thereby forming a metallized portion of the guide hole where the contact probe 10 is in contact, in particular where the contact probe 10 makes sliding contact.

[0117] Preferably, the conductive portion 21 can completely cover part or all of the wall of the guide hole (in this case, the metallized portion coincides with the entire wall 40W of the hole), or the conductive portion 21 can be configured to only partially cover the wall 40W of the guide hole.

[0118] According to embodiments of the present invention, contact between the contact probe 10 and the conductive portion 21 occurs through at least a portion of an elastically flexible intermediate section 10s appropriately configured to make such contact, for example, this contact is a sliding contact. Several embodiments are shown below.

[0119] In general, contact with the conductive portion 21 can be made through at least a portion of the elastically flexible intermediate section 10s and / or through the stopping means of the contact probe 10, which will be described in more detail below. Because the contact probe is very short, it is therefore advantageous to utilize these components for contact with the metallization 21.

[0120] Furthermore, Figure 12 and subsequent figures show a probe having an elastically flexible intermediate section 10s with a stepped section, but it should be noted that any geometry of the probe can be used with the conductive portion 21 described above. In this regard, Figures 17A and 17B and Figure 27B (discussed in detail below) show some of the many possible embodiments.

[0121] Given the importance of the conductive portion 21, it is necessary to ensure optimal contact between the contact probe 10 and the conductive portion 21 (for example, between the probe and the metallized wall of the guide hole) during device testing, and for example, the above-mentioned sliding contact between the probe and the hole must always be ensured (however, in some configurations, this contact can be a pressing contact, for example, contact of a stopper on the conductive portion as discussed below).

[0122] In an advantageous embodiment of the present invention described above and shown in detail in Figures 16A-16B and 17A-17B, to improve electrical contact between the contact probe 10 and the conductive portion 21, the elastically flexible intermediate section 10s is structured as a plurality of interconnected elastic elements (or elastic sub-parts, reference numeral 10sr') that follow one another along the longitudinal axis HH of the contact probe 10. As depicted in the above figures, each of the elastic elements 10sr' is configured to be compressed under the action of pressure generated during testing of the device under test, during which its dimension along the longitudinal axis HH of the contact probe 10 is reduced, its lateral dimension is increased, and consequently it undergoes a lateral bend that brings it closer to the wall of the guide hole.

[0123] As shown in the embodiments of Figures 16A-16B and 17A-17B, the elastic elements 10rs' are formed as interconnected rings, each having an elliptical shape that extends longitudinally along the longitudinal axis HH of the contact probe 10; that is, these rings are stretched longitudinally along the probe to increase lateral bending (and thus, generally speaking, they are elastic elements with an elongated shape along the longitudinal axis HH). These rings can have a closed or semi-closed profile.

[0124] This configures the elastic element 10sr' to contact the conductive portion 21 (at least partially covering the wall of the guide hole 40h) through its at least one side wall (indicated by reference numbers W1 and / or W2) after an increase in its lateral dimension during testing of the device under test, ensuring optimal contact with the metallization described above (as shown in Figure 17B). In other words, when overdrive is applied, a single ring expands to contact the corresponding wall portion of the guide hole 40h.

[0125] In one embodiment, the first wall (wall W1 in the figure) of at least one elastic element 10sr' facing the corresponding wall of the guide hole 40h (wall 40W1 in the figure's embodiment) is elastically weaker than its second wall (i.e., wall W2 in this embodiment) located on the opposite side with respect to the longitudinal axis HH. Generally, it is possible to provide embodiments in which the entire wall of one of the two walls of the elastic section described above has lower elasticity, thereby changing the deformation characteristics of the contact probe 10 so that it does not deform symmetrically. Thereafter, only one of the walls of the contact probe 10 contacts the metallization in question (i.e., the ring contacts the single wall of the guide hole by expanding, particularly through the elastically weaker portion), thereby avoiding the problem of interlocking, while at the same time ensuring optimal contact and generating beneficial scrubbing action of the contact tip as much as possible.

[0126] Referring next to Figure 18, in one embodiment of the present invention, the contact probe 10 also includes a stopping means formed on its body 10', which is configured to mechanically contact at least a portion of the guide 40 to hold the probe within the probe head 100.

[0127] This allows the position of the contact probe 10 within the probe head 100 to be fixed, preventing it from sliding out of the guide hole 40h.

[0128] In a particular embodiment shown in Figure 18, the stopping means is formed as a stopper having a lateral extension (and indicated by reference no. 50) that defines at least one shoulder portion (reference no. S1 or S2) configured to abut against the upper surface FB of the guide 40, i.e., against the surface opposite to the surface FA facing the device under test (and thus having at least one contact surface). Thus, the stopper 50 protrudes from at least one wall of the contact probe 10 (overall, the stopper 50 bonded to the probe body portion can have a lateral extension larger than that of the guide hole for properly holding the contact probe).

[0129] In particular, in a preferred embodiment, the stopper 50 comprises two shoulders S1 and S2 that are symmetrical with respect to the longitudinal axis HH of the contact probe 10 and define two surfaces for contacting the surface FB of the guide 40. It should be noted again that the figure is merely an example of the application of the present invention, and other configurations of the stopper can obviously be employed (for example, the stopper may protrude from only one wall of the contact probe 10 rather than from two opposing walls as depicted, and may also have any suitable configuration).

[0130] In addition or alternatively, in one embodiment of the present invention depicted in Figure 19, the probe stopping means comprises at least one clip 60 configured to mechanically interfere with a guide hole 40h and thereby contact the wall 40W of the guide hole 40h. More specifically, the clip 60 protrudes from the body 10' of the contact probe 10 and is configured to elastically deform during contact with the wall 40W of the guide hole 40h, thereby holding the contact probe 10 by mechanical interference with the guide hole 40h.

[0131] In the embodiment shown in the figure, the clip 60 is formed on the surface FA of the guide 40, that is, on the lower surface facing the device under test DUT.

[0132] The presence of the stopper 50 and / or the clip 60 prevents the contact probe 10 from coming out of the guide hole 40h when the device under test and / or the PCB is absent (and therefore, in the latter case, when the probe head 100 is inverted), thus simplifying the handling of the probe head 100.

[0133] In a preferred embodiment, there are two clips 60 arranged symmetrically on the body 10' with respect to the longitudinal axis HH, and these clips 60 are configured to contact the respective walls 40W of the guide hole 40h, ensuring interlocking of the movement of the contact probe 10.

[0134] Clearly, a combination of stopper 50 and clip 60 can also be provided, as shown in the embodiment of Figure 20.

[0135] In general, it is preferable that the clip 60 has a lower stiffness than the elastically flexible intermediate section 10s, so as to avoid deformation of the contact probe 10 during assembly, but also to ensure that the contact probe 10 can be properly handled along the longitudinal axis HH during testing.

[0136] Suitablely, in the presence of conductive portions 21 for short-circuiting a group of probes, contact between the contact probe 10 and the conductive portion 21 can be pressurized contact by the shoulders S1 and / or S2 of the stopper 50, as shown in the embodiment of Figure 21A, or contact with one or more walls 40W of the guide hole 40h via one or more clips 60, as shown in the embodiment of Figure 21B, or a combination of both embodiments. Additionally, or alternatively, as described above and as will be discussed in more detail below, contact between the contact probe 10 and the conductive portion 21 can be sliding contact between at least one wall of the contact probe 10, in particular at least one wall of the elastically flexible intermediate section 10s, and at least one corresponding wall 40W of the guide hole 40h.

[0137] With regard to the retention of the contact probe 10, it is also possible to provide an embodiment in which the guide hole 40h is not linear (i.e., has a non-linear section), as shown in Figure 22, thereby preventing the contact probe 10 from coming loose. In other words, at least one guide hole 40h of the guide 40 has at least one wall inclined with respect to the longitudinal axis HH, and the guide hole 22h has a non-linear cross-sectional shape. Preferably, the guide hole 40h has a pair of inclined opposing walls, so that the desired retention is properly achieved without the need to introduce a stopping means for the contact probe 10.

[0138] Furthermore, referring to Figure 23, according to one embodiment of the present invention, the contact probe 10 comprises a plurality of elastically flexible intermediate sections 10s' and 10s'' separated from each other by a portion of the body 10' of the contact probe 10, and these elastically flexible intermediate sections 10s are connected to each other along the longitudinal axis HH. Figure 23 shows an embodiment in which two elastic sections are present, but it is also possible to have a different number of elastic sections.

[0139] The use of several elastically flexible intermediate sections involves an increased presence of rigid portions of the contact probe 10, and such embodiments can be implemented to adjust the moment of the probe and facilitate its handling.

[0140] In a real probe head with several contact probes, it should be noted that these probes differ in length from one another, and the height of the probe head also differs. For example, the distance between the guide and the PCB (which substantially corresponds to the height of the frame F) may be smaller than expected, and may be the minimum height within the expected tolerance range. In this case, there is a risk that contact with the PCB will not be made correctly, and / or that the pressure exerted on the contact probe 10 will cause deformation of the stopper 50.

[0141] To solve this problem, in a highly advantageous embodiment of the present invention shown in Figure 24, the contact probe 10 includes an elastic portion (indicated by reference numeral 10pr) positioned between the stopper 50 and its second end 10b, i.e., in the non-driven region of the probe (particularly the non-driven upper region). This elastic portion 10pr is configured to be pre-compressed in a stationary state (i.e., when no tests are being performed) after the assembly of the probe head 100, and thus, once pre-compressed, is capable of exerting a pre-load force Fpr, which is directed substantially along the longitudinal axis HH.

[0142] Thanks to this solution, the elastic portion 10pr ensures proper pre-compression of the contact probe 10, thus guaranteeing optimal contact between the contact probe 10 and the interface card 30 at all times, and making it possible to adapt it to various tolerances / dimensions.

[0143] Therefore, in this case, the contact force with the pad is generated not only by the overtravel of the contact probe 10, but also by the preload force exerted by the elastic portion 10pr.

[0144] The pre-loaded elastic section 10pr ensures optimal braking through contact with the pad, in addition to braking provided by the elastically flexible intermediate section 10s.

[0145] Clearly, as shown in Figure 25, the above solution (providing a preload spring) can be combined with any of the embodiments described above, and therefore, in addition to the stopper 50, one or more clips 60 and one or more conductive parts 21 can be provided, as well as many other configurations depending on requirements and / or needs.

[0146] The preloaded elastic portion 10pr is formed, for example, by removing some material from the probe body 10', but any suitable manufacturing method can also be provided.

[0147] In embodiments not shown, a plurality of preloaded elastic portions 10pr may be provided between the stopper 50 and the second end 10b, these preloaded elastic portions 10pr being separated from each other by a portion of the probe body 10' and continuing along the longitudinal axis HH.

[0148] The length of the preloaded elastic portion 10s is between 500 μm and 50 μm, for example, preferably between 100 μm and 50 μm, and its length and shape are such that they ensure an appropriate preloading force for the contact probe 10.

[0149] Next, referring to the embodiment in Figure 26, the elastically flexible intermediate section 10s is at least partially embedded in a polymer material (identified here by reference no. P), thereby ensuring better mechanical stability of the contact probe 10 as a whole. For example, the elastically flexible intermediate section 10s can be completely embedded in the polymer material P, and therefore, in this case, the material can extend completely into the guide hole 40h.

[0150] In one embodiment, the polymer material P is a polyamide or selected from other materials similar to polyamide materials, but the present invention is not limited by the polymer coating material used, because any suitable material can be selected based on the requirements.

[0151] In this case, the presence of the polymer material P increases the elastic response of the elastically flexible intermediate section 10s itself, thereby ensuring greater strength against lateral deformation.

[0152] Clearly, this embodiment can be combined with other embodiments, such as the presence of the conductive portion 21, any of the geometries described herein, or any of the guide configurations, as shown in Figure 26bis, for example (or, although not shown, the preloaded elastic portion 10pr can also be embedded in the polymer material).

[0153] Furthermore, in the embodiments shown in Figures 27A and 27B, the elastically flexible intermediate section 10s is divided into a plurality of elastic sub-parts, elastic elements, or elastic half-sections (indicated in this case by reference no. 10sr"), and these elastic sub-parts, elastic elements, or elastic half-sections are not aligned with respect to each other with respect to the same reference axis (for example, they are not aligned with respect to the longitudinal axis HH of the probe when taken as a reference).

[0154] For example, the elastic elements 10sr'' unfold along their respective axes, which are as parallel as possible to each other (and indicated by reference numbers H'-H', H''-H''), and these axes do not necessarily coincide with the longitudinal axis HH of the probe.

[0155] Therefore, in this embodiment, the elastically flexible intermediate section 10s is formed by various sections (i.e., elastic elements) that are not aligned along the longitudinal axis of the contact probe 10, i.e., along the vertical reference axis.

[0156] The elastic elements 10sr'' are continuous and uninterrupted from one another, with their respective axes of symmetry being (appropriately shifted) and not coincident with each other, and are shifted from one another (i.e., offset along the vertical reference axis) to define an elastically flexible intermediate section that is not a straight line as a whole.

[0157] Therefore, generally speaking, according to this embodiment, the elastically flexible intermediate section 10s is structured as a plurality of elastic elements 10sr'' that are continuous with each other such that the cross-section of the elastically flexible intermediate section is nonlinear, and at least one of the elastic elements is in contact with the wall of the guide hole. In particular, at least two of the elastic elements 10sr'' can not be aligned with each other with respect to a reference axis orthogonal to the guide, i.e., a vertical axis (for example, the longitudinal axis HH of the contact probe 10 as described above).

[0158] Ideally, at least one of these elastic elements 10sr” is in contact with the wall 40W of the guide hole 40h and, in particular, with the conductive portion 21 extending within this hole (as shown in Figure 27B), thereby achieving the desired electrical contact with metallization while simultaneously achieving simple retention of the contact probe 10.

[0159] According to one embodiment, one or more edges of the elastic element 10sr'' (in particular, the edges of the elastic element that are in contact with the wall 40W of the guide hole 40h, i.e., protruding portions) are beveled (i.e., provided with a beveled surface 10bl) in order to avoid interlocking of the contact probe 10 in the guide hole, in particular to avoid interlocking during assembly.

[0160] This embodiment is advantageous because it envisions the formation of a non-linear or curved intermediate elastic section, ensuring that the contact probe 10 remains in place during testing of the device under test while maintaining proper contact with the wall of the guide hole 40h and therefore with the associated metallization. In particular, in this embodiment (as seen in the embodiment of Figure 9), the elastic section 10s has a larger cross-sectional dimension (at least locally) than the cross-sectional dimension of the guide hole 40h (as shown in Figures 27A and 27B), creating friction between the elastic section 10s and the wall of the guide hole 40h. This friction prevents the contact probe 10 from coming out of the guide 40, for example during maintenance of the probe head 100, and ensures better electrical contact with the conductive part 21 (Figure 27B).

[0161] Referring next to Figure 28, the guide 40 may comprise a first guide 40a having a first guide hole 40ah, and a second guide 40b associated with the first guide 40a and having a second guide hole 40bh.

[0162] In one embodiment, the first guide 40a and the second guide 40b are preferably positioned close to the intermediate region of the probe head 100 (between the semiconductor wafer 20 and the interface card 30), but this is not necessarily required.

[0163] In other words, in this embodiment, the probe head 100 preferably comprises two intermediate guides, a first guide 40a and a second guide 40b.

[0164] The elastically flexible intermediate section 10s is positioned in one of the first guide hole 40ah and the second guide hole 40bh (in the embodiment of Figure 28, the elastically flexible intermediate section 10s is positioned in the first lower guide hole 40ah, but the present invention is not necessarily limited to this particular configuration).

[0165] Appropriately, the contact probe 10 further comprises intermediate stopping means positioned between the first guide 40a and the second guide 40b, and these intermediate stopping means are not limited to a particular type and can have various configurations (including the aforementioned configurations depicted in Figures 18-20), as detailed below. Generally, the intermediate stopping means are configured to mechanically contact at least a portion of the first guide 40a and / or the second guide 40b for holding the contact probe 10 within the probe head 100, in particular to prevent it from sliding out of the first guide hole and / or second guide hole, for example, when the device under test and / or PCB is not present.

[0166] For example, as shown in Figure 28, the intermediate stopping means includes an intermediate stopper (identified here by reference no. 50'), which may have the same configuration as the stopper 50 discussed with reference to Figure 18 (it may protrude from two walls, or even from one wall, or in any suitable general configuration). Thus, the intermediate stopper 50' has a lateral extension to define at least one shoulder portion (in particular, two shoulder portions S1' and S2') configured to abut the surfaces of the first guide 40a and / or the second guide 40b, and thus define a contact surface for abutting these surfaces (as mentioned above, as a whole, the stopper 50' bonded to the probe body portion may have a lateral extension larger than that of the guide hole for properly holding the contact probe).

[0167] Therefore, the presence of the intermediate stopper 50' ensures that the contact probe 10 is properly held within the probe head 100, and in particular, the combination of the intermediate stopper 50' with the first guide 40a and the second guide 40b prevents the contact probe from coming out in either direction, thus allowing the short contact probe 10 to be held in an easy manner when neither the semiconductor wafer 20 nor the interface card 30 is present.

[0168] As shown in Figure 29, in one embodiment of the present invention, the intermediate stopper 50' can be configured to abut against a conductive portion 21 formed on the surface of the first guide 40a or the second guide 40b, thereby forming an electrical connection with the conductive portion 21 and thus enabling a short circuit of the contact probe 10 within the corresponding domain. In the embodiment of Figure 29, the intermediate stopper 50' abuts against the lower surface of the second upper guide 40b where the conductive portion 21 is located, through its shoulder portions S1' and S2', although the conductive portion 21 can be formed on the first lower guide 40a to which the intermediate stopper 50' can abut. Generally, the conductive portion 21 can be formed on the surfaces FA and / or FB of the first guide 40a and / or the second guide 40b, and can also be formed in any suitable manner (even such as being embedded within the guide). Furthermore, it is possible to provide multiple conductive parts corresponding to multiple conductive domains, and these conductive parts are arranged on the same surface of the first guide 40a and / or the second guide 40b, or on opposite surfaces of the first guide 40a and / or the second guide 40b.

[0169] Figure 29 shows only two contact probes 10 short-circuited by the conductive portion 21 as an example, but it should be noted that the present invention is not limited thereto, and group 40h' can comprise any number of guide holes, and therefore any number of contact probes 10.

[0170] Therefore, in the embodiment shown in Figure 29, the contact between the contact probe 10 and the conductive part 21 is a pressing contact by one or more contact surfaces of at least one shoulder portion S1 and / or S2 of the intermediate stopper 50', and in this way an electrical connection is formed between the contact probe 10 and the conductive part 21.

[0171] It should be noted that, in general, everything that has been shown so far regarding the conductive portion 21 is also applicable to the present invention which provides a double intermediate guide, and it is equally possible to apply all of the above geometries of the contact probe to this embodiment.

[0172] To increase contact with the aforementioned metallization and enhance the performance of the probe head 100, the intermediate stopper 50' is provided with a plurality of projections (and identified here by reference numeral 50p) protruding from at least one of the shoulders (i.e., they protrude from the contact surfaces defined by the shoulders S1' and / or S2' described above), as depicted in the embodiment of Figure 30. In particular, the projections 50p are configured to contact a portion of the conductive portion 21, forming an optimal electrical connection with the conductive portion 21.

[0173] Furthermore, it should be noted that the present invention is not limited by the specific shape of the projection 50p; for example, the projection 50p can be triangular-toothed (as shown in Figure 30), but any suitable shape can be used. In one embodiment, the projection 50p can be generally defined by the surface irregularities of the intermediate stopper 50'. In addition to, or as an alternative to, those shown in Figure 30, these projections 50p can also project downward so as to abut against the first guide 40a.

[0174] Furthermore, it should be noted that the presence of projections 50p can be assumed even in the case of a single guide, that is, for example, in the case of Figure 18 or 21A, along with projections that protrude downward to improve the quality of contact with the guide, particularly the quality of contact with the metallization 21 formed on the upper surface of the guide 40.

[0175] According to the embodiment shown in Figure 31, the probe head 100 may also be equipped with an additional stopper (also referred to here as the “upper stopper” and indicated by reference numeral 50”), the above-mentioned additional stopper is positioned to abut against the upper surface FB of the second guide 40b, which is the surface furthest from the device under test. In other words, the upper stopper 50”) functions as a cap to hold the contact probe 10 more effectively. The upper stopper 50”) may have the same shape and dimensions as the intermediate stopper 50', but this is not strictly required.

[0176] Furthermore, in this embodiment, which assumes the presence of a first guide 40a and a second guide 40b, it should be noted that the probe is housed in the first guide 40a, and then the latter is attached to the contact probe 10.

[0177] Furthermore, to facilitate the assembly of the probe head 100, a retaining element formed as an elastic hook (indicated by reference numeral 90 in Figure 32) can be provided instead of the intermediate stopper 50'. In particular, this elastic hook 90 is configured to elastically deform during the insertion of the contact probe 10, for example, when it is inserted from above through the second guide hole 40bh, as well as during the withdrawal of the contact probe 10 through other guide holes, i.e., through the first lower guide hole 40ah (and thus by forced withdrawal from below).

[0178] Once the probe head 100 is assembled, the elastic hook 90 is housed between the first guide 40a and the second guide 40b, in an undeformed configuration that allows it to mechanically contact the first guide 40a and / or the second guide 40b for holding the contact probe 10.

[0179] Advantageously, this allows the contact probe 10 to be inserted with the first guide 40a and the second guide 40b already assembled in their operating positions, while withdrawing the contact probe 10 only requires pulling the latter downward through its first end 10a, i.e., through its lower end, greatly simplifying the assembly and potential maintenance of the probe head.

[0180] According to a further embodiment of the present invention shown in Figure 33, the intermediate stopping means may comprise an elastic film, such as a Kapton® sheet, positioned between a first guide 40a and a second guide 40b (and shown herein by reference no. 95).

[0181] Referring next to Figure 34, a particularly advantageous embodiment provides the presence of a first elastically flexible intermediate section 10san (also referred to for convenience as the "first spring" or "lower spring") in a first guide hole 40ah, and a second elastically flexible intermediate section 10sb (also referred to for convenience as the "second spring" or "lower spring") in a second guide hole 40bh. An intermediate stopping means (for example, the intermediate stopper 50' (see Figure 34) or the aforementioned elastic hook 90 (see Figure 35)) is positioned between the first elastically flexible intermediate section 10sa and the second elastically flexible intermediate section 10sb.

[0182] This embodiment has the advantage of allowing for more precise control of the movement (particularly compression) of the contact probe 10, and therefore, more optimally determining and controlling the contact force in general. For example, this makes it possible to more precisely control the vertical movement along the longitudinal axis HH, but as mentioned above, even in this case, various geometries of the elastically flexible intermediate sections 10sa and 10sb are also possible with movement in various directions.

[0183] The first elastically flexible intermediate section 10sa may have a different elastic constant ka than the second elastically flexible intermediate section 10sb, which has a different elastic constant kb. Generally, these elastic constants can be appropriately selected.

[0184] Let xa and xb be the entities of compression experienced by the first and second springs, respectively. Then, the reaction force FR exerted by the contact probe 10 during the test (and therefore during its compression) is given by the known relationship FR = -ka × xa - kb × xb. As a mere example, assuming that the overdrive of the contact probe 10 is 100 μm, the elastic constants ka and kb can be selected such that the first spring 10sa has a compression of 70 μm, while the second spring 10sb has a compression of 30 μm. That is, in this case, the first spring 10sa has an elastic constant ka greater than the elastic constant kb of the second spring 10sb. Also, assuming that the distance d between the intermediate stopper 50' and the lower surface FA of the second guide 40b is equal to 30 μm, it is certainly guaranteed that the intermediate stopper 50' will contact the lower surface FA.

[0185] All of this is particularly advantageous when the groups of probes are short-circuited by the conductive part 21 (see Figure 36 for this purpose), because pressing contact with the conductive part 21 is always guaranteed by adjusting the elastic constant of the spring (thus, for example, by selecting the guide to be contacted, contact is thereby guaranteed and with appropriate contact force). As mentioned above, this contact can be further improved by the presence of projection 50p, as shown in Figure 37.

[0186] Clearly, the various embodiments described above can be combined, for example, to also provide the presence of an upper stopper 50” (as shown in Figure 38) in the presence of one or more conductive parts 21 in some cases.

[0187] Furthermore, in embodiments not shown, the first guide 40a and the second guide 40b can be shifted from each other with respect to the longitudinal axis HH (i.e., the respective holes cannot be aligned with each other along the vertical reference axis), which is further advantageous for (sliding) contact with the wall of the guide hole 40h.

[0188] Referring next to the embodiment shown in Figure 39, the second end 10b of the contact probe 10 can be structured to include an arm 10bar that protrudes laterally from the probe body 10' and is configured to contact the contact pad 30b of the interface card 30. The protruding arm 10bar is configured to offset the contact point between the contact probe 10 and the contact pad 30b of the interface card 30 with respect to the longitudinal axis HH of the contact probe 10.

[0189] In the example shown in Figure 39, the arm 10bar extends along an axis YY that is substantially perpendicular to the longitudinal axis YY, but this is not strictly necessary.

[0190] This embodiment has the advantage that, due to the shape of the contact probe 10 itself, which has an arm 10bar protruding from the probe body 10', the contact pads formed on the interface card 30 are spatially redistributed compared to those of the device under test without using a space transformer interposed between the probe and the PCB. Therefore, it is possible not to place an interposer between the PCB and the probe head 100, and as a result, in this embodiment, the interface card 30 is the PCB.

[0191] Furthermore, in embodiments not shown, the probe head 100 may be equipped with a contact probe having arms 10bar of different lengths to obtain a more effective spatial redistribution of the contact pads 30b on the PCB 30 compared to that of the device under test, the length of the arms 10bar being measured along their longitudinal deployment direction YY. The presence of arms of different lengths makes it possible to change the pitch of the pads 30b on the PCB compared to the pitch of the pads 20a on the device under test, and in particular, to relax the constraints on the distance between the centers of the contact pads on the PCB compared to that of the device under test. The length and arrangement of the arms 10bar are modifiable in the probe and selected based on specific requirements, and in some cases, contact probes without arms may also exist to obtain a particularly effective configuration.

[0192] This embodiment is particularly advantageous in the case of large probe heads, such as those used in testing storage devices like DRAM, because it allows for the use of fewer components with the configuration shown herein. In particular, it avoids the presence of complex, costly, and very time-consuming space transformers, such as MLC (an acronym for "Multi Layer Ceramic") or MLO (an acronym for "Multi Layer Organic"), between the PCB and the probe head. Furthermore, the probe head can be interfaced with a PCB having a simpler and less expensive structure and a looser pitch (e.g., a pitch with a larger relative distance to the device under test, and therefore lower density, and / or a configuration selected in a simple way based on the needs).

[0193] In the embodiment shown in Figure 39, actual contact between the PCB 30 and the pad 30b is made by a contact element formed on the upper surface of the arm 10bar, for example, at its free end. However, this contact element does not necessarily have to be pointed and can have other shapes than those shown in the figure.

[0194] Clearly, the embodiment in Figure 39 can be combined with other embodiments, and therefore, for example, it is possible to provide a stopper, a preloaded elastic portion between the stopper and the arm 10bar, contact with a conductive part, and many other configurations, or one or more of a double guide and intermediate stopper element (as shown in Figure 39bis).

[0195] Next, referring to the embodiment shown in Figure 40, the first end 10a (i.e., the lower end) of the contact probe 10 is made of a high-hardness material 10ins, other materials may also be used, but in particular it may include a material having a higher hardness compared to the material of the probe body 10', such as rhodium.

[0196] Clearly, Figure 40, in which the high-hardness material constitutes the entire terminal portion of the contact probe 10, is provided merely as an example, and other configurations are also possible. Generally, the high-hardness material 10ins can be configured to make contact with the pad 20a of the device under test, thus ensuring that the contact tip has high hardness at least partially. For example, in one embodiment, the high-hardness material 10ins can be an insert supported by a supplementary section of the probe body 10' and intended to make contact with the pad 20a of the device under test, or it can be a coating or layer of material on the first lower end 10a, or any suitable configuration. In other cases, the tip can be made of a layer of high-hardness material that forms the core.

[0197] This embodiment in Figure 40 ensures a long service life for the contact probe 10 while maintaining high-quality contact.

[0198] This embodiment can also be combined with all the embodiments described above, since all the embodiments described above relate to the first end 10a of the contact probe. Figure 40bis shows a combination of a double guide and an intermediate stop means.

[0199] Finally, referring to the embodiment in Figure 41, it should be noted that the actual length of the contact probe 10 is increased by the presence of the elastically flexible intermediate section 10s, which is characterized by several loops (and, more generally, by a continuum of various elastic elements or parts or elastic subsections constituting the elastic section 10s as described in the above embodiments). To solve this problem, the elastically flexible intermediate section 10s is provided with at least one protruding element or bump (reference number B) on at least one of its elastic elements, configured to contact an adjacent elastic element during testing of the device under test (i.e., when the elastic section 10s is compressed), thereby causing an electrical connection between the elastic elements, shortening the actual length of the elastically flexible intermediate section 10s, and improving the performance of the probe head 100 (in practice, a shorter path for the current is formed).

[0200] As a result, in this embodiment, at least one of the elastic elements of the elastically flexible intermediate section 10s (divided into a plurality of elastic elements that are continuous with each other as described above) comprises a protruding element B configured to project toward an adjacent elastic element and to contact a portion of the adjacent elastic element during testing of the electronic device, the portion being separated from the protruding element B in a stationary state (i.e., when the elastic section is not compressed).

[0201] In other words, in this embodiment, the elastically flexible intermediate section 10s includes protruding elements B configured to create electrical contact between the portions of the elastically flexible intermediate section 10s that would otherwise be separated.

[0202] The protruding element B can be formed integrally with the elastically flexible intermediate section 10s, but the present invention is not limited by the manufacturing method.

[0203] For example, the protruding element B can be formed on the edge or loop of each elastic element, but other configurations are also possible.

[0204] It is also possible to provide multiple protruding elements B, the number of which is selected based on the length selected during compression of the elastically flexible intermediate section 10s, that is, based on the length to be obtained. Since the length of the elastic section becomes longer when compressed as there are more protruding elements B, it is preferable to limit the number of protruding elements B.

[0205] This embodiment in Figure 41 is applicable to all geometries described so far for the elastically flexible intermediate section 10s, or to various configurations of guides and holes, but for simplicity, Figure 41 shows only the stepped cross-sectional shape of the elastically flexible intermediate section 10s. Figures 42-46 are examples of combinations of bump B according to this embodiment, with a non-linear elastically flexible intermediate section, with the presence of a pre-loaded elastic portion, with the presence of a polymer material P, with the presence of a conductive portion 21 (with further improvement of frequency performance; in this case, the figure simply shows one of many possible configurations and a stopper may not be present), and with a double guide and intermediate stopper means, respectively.

[0206] In summary, the present invention successfully overcomes the technical challenges and provides the above-mentioned probe head (equipped with a very short contact probe that functions as an elastic spring), solving all the shortcomings of the prior art in a simple manner.

[0207] Advantageously, according to the present invention, it is possible to effectively control the strength of the contact force, and more generally, the compression of the contact probe, and to appropriately form and make the elastically flexible intermediate section to the appropriate size. However, it is also possible to adjust the strength of the contact force by changing the overtravel of the probe, starting from a predetermined configuration of the elastically flexible intermediate section.

[0208] In general, regardless of the manufacturing method (for example, by removing some material from the main body to locally reduce its rigidity), a reduced-rigidity elastic section is obtained, and this elastic section is formed by elastic elements that are successive to each other and are their basic units.

[0209] By shortening the length of the contact probe described above, it can be viewed as a microspring, and the probe head of the present invention is suitable for testing high-frequency devices while solving the rigidity problem of short probes in known solutions.

[0210] Furthermore, the specific configuration described above ensures proper stability of the contact probe, preventing deformation during testing, and allowing for proper handling and easy assembly.

[0211] Unlike vertical probe heads manufactured according to conventional technology, probe heads according to several embodiments further allow the use of a single guide, where the contact probe deforms within the guide hole. Using a single guide simplifies the assembly of the probe head and is more economically advantageous, while using two guides allows for the extension of the elastic section.

[0212] This allows for configurations that provide first and second intermediate guides, for example, for more effective retention of the contact probe and greater flexibility in the selection of various possible configurations (having intermediate stopping means and advantageous configurations). The presence of dual guides, intermediate stopping means, and one (preferably two) elastic sections in each hole further helps to ensure proper preloading of the contact probe.

[0213] A variety of geometries can be provided for the elastic section, as well as various directions and types of deformation, not necessarily limited to the longitudinal direction. For example, in addition to helical springs and symmetrical springs with stepped cross-sections, other shapes (asymmetrical shapes and shapes with lateral deformation) are also possible.

[0214] Furthermore, the presence of a preloaded spring ensures proper contact in all situations, regardless of the manufacturing tolerances of the probe head.

[0215] Furthermore, high performance is guaranteed by using a conductive part that a portion of the short probe makes contact with.

[0216] Furthermore, the probe head of the present invention, due to its advantageous shape, limits the wear of the contact pad.

[0217] Furthermore, the presence of polymer materials allows for an increase in the elastic response of the elastically flexible intermediate section itself, ensuring greater strength against lateral deformation while improving elastic and mechanical properties.

[0218] Furthermore, the presence of bumps ensures high-frequency performance and shortens the actual length of the elastic section.

[0219] Finally, it should be noted that all of the above embodiments can be combined with each other, even if their combinations are not explicitly shown or described. For example, it is possible to combine two or more of the following advantageous configurations: a particular shape of the turn, a particular nonlinear shape of the elastically flexible intermediate section, a particular arrangement of metallization, the presence of a preloaded elastic part and stopping means, the presence of a spring-embedded polymer material, the presence of a double intermediate guide, the presence of a bump or protruding element, various shapes of the stopping means, the presence of a protruding arm, the presence of a tip made of a high-hardness material, or even two or more of the above configurations can be combined with any configuration suitable for a variety of applications.

[0220] Although most of the figures show elastically flexible intermediate sections with stepped cross-sections to avoid complicating the explanation, various embodiments (e.g., configurations of one / more guides, presence of pre-loaded elastic sections, various configurations of holes or stopping means, etc.) can also be applied to other geometries described.

[0221] Clearly, to satisfy non-specific and specific requirements, those skilled in the art can make various modifications and variations to the probe head described above, all of which fall within the scope of protection of the present invention as defined by the following claims.

Claims

1. A probe head (100) for testing electronic devices, The probe head (100) is A contact probe (10) comprising at least one body (10') extending along the longitudinal axis (H-H) between a first end (10a) and a second end (10b), wherein the ends (10a, 10b) are configured to contact the respective contact pads (20a, 30b), A guide (40) having at least one guide hole (40h) configured to accommodate at least a portion of the contact probe (10), Equipped with, The contact probe (10) comprises at least one intermediate section (10s) positioned between the first end (10a) and the second end (10b) and being elastically flexible at least along the longitudinal axis (H-H), The elastically flexible intermediate section (10s) is configured to determine the strength and / or direction of the contact force (FC) exerted on the contact pads (20a, 30b) by the contact probe (10), and the contact probe (10) functions as a spring. Probe head (100).

2. The probe head (100) according to claim 1, wherein the length of the contact probe (10) measured along the longitudinal axis (H-H) is less than 2000 μm, preferably less than 1000 μm, and more preferably 800 μm or less.

3. The probe head (100) according to claim 1 or 2, wherein the guide (40) comprises a first guide portion (40') and a second guide portion (40''), the second guide portion (40'') being initially manufactured structurally independently of the first guide portion (40') and subsequently associated with it.

4. The second guide portion (40") is attached to the contact probe (10) by overlapping it with the first guide portion (40'), and / or The second guide portion (40") is connected to the first guide portion (40') by mounting means. The probe head (100) according to claim 3.

5. The probe head (100) according to any one of claims 1 to 4, wherein the elastically flexible intermediate section (10s) is obtained by interlocking engravings formed on the body (10') of the contact probe (10), and the interlocking engravings are configured such that the contact probe (10) functions as an elastic spring.

6. The probe head (100) according to any one of claims 1 to 5, wherein the elastically flexible intermediate section (10s) is serrated or structured as a plurality of polygonal elastic elements that are connected to one another along the longitudinal axis (H-H), such as a series of interconnected hexagons.

7. The probe head (100) according to claim 1, wherein the elastically flexible intermediate section (10s) is structured as a plurality of elliptical elastic elements that are connected to one another along the longitudinal axis (H-H) of the contact probe (10).

8. The probe head (100) according to any one of claims 1 to 7, wherein the contact probe (10) has a non-circular cross-section, preferably a rectangular cross-section, more preferably a rectangular cross-section having a first side having a length of 30 μm and a second side having a length of 70 μm.

9. The probe head (100) according to any one of claims 1 to 8, wherein the contact probe (10) comprises a plurality of elastically flexible intermediate sections (10s', 10s'') separated from each other by a portion of the body (10') of the contact probe (10), and the elastically flexible intermediate sections (10s', 10s'') are connected to each other along the longitudinal axis (H-H).

10. The probe head (100) according to claim 1, wherein the elastically flexible intermediate section (10s) is positioned on the guide (40) so as to be at least partially housed within the guide hole (40h).

11. The probe head (100) according to claim 1, comprising a lower guide (45l) and an upper guide (45u) separated from each other by a gap (G), wherein the lower guide (45l) and the upper guide (45u) each comprise a lower guide hole (45lh) and an upper guide hole (45uh) for housing the contact probe (10).

12. The probe head (100) according to claim 11, wherein the elastically flexible intermediate section (10s) is positioned in the gap (G) between the lower guide (45l) and the upper guide (45u).

13. The probe head (100) according to claim 11 or 12, wherein the lower guide hole (45lh) and the upper guide hole (45uh) are not aligned with respect to each other.

14. The probe head (100) according to any one of claims 1 to 13, wherein the elastically flexible intermediate section (10s) extends along the longitudinal axis (H-H) for a length of 1000 μm to 80 μm and at a pitch of 100 μm to 5 μm.

15. The probe head (100) according to any one of claims 1 to 14, wherein the contact probe (10) is made from a material selected from Pd, PdCo, ​​Ni, NiCo, Au, Pt, Ag, Rh, or a combination thereof.

16. The probe head (100) according to any one of claims 1 to 15, wherein at least one guide hole (40h) comprises at least one wall inclined with respect to the longitudinal axis (H-H), and the guide hole (40h) has a non-linear cross-sectional shape.

17. The probe head (100) according to claim 16, wherein the guide hole (40h) comprises a pair of inclined opposing walls.

18. The elastically flexible intermediate section (10s) is configured such that the contact force (FC) exerted on the contact pads (20a, 30b) by the contact probe (10) has a substantially zero lateral component and is substantially directed along the longitudinal axis (H-H), or The contact force (FC) also has a component along an axis different from the longitudinal axis (H-H), for example, a lateral component. The probe head (100) according to claim 1.

19. The probe head (100) according to any one of claims 1 to 18, wherein the second end (10b) of the contact probe (10) comprises an arm (10bar) that protrudes laterally from its body (10') and is configured to contact the contact pad (30b) of the interface card (30), and the arm (10bar) is configured to offset the contact point between the contact probe (10bar) and the contact pad (30b) of the interface card (30) with respect to the longitudinal axis (H-H) of the contact probe (10).

20. The probe head (100) according to claim 19, comprising a plurality of contact probes having arms (10 bar) of different lengths, wherein the length of the arms (10 bar) is measured along the longitudinal deployment direction (Y-Y).

21. The probe head (100) according to any one of claims 1 to 20, wherein the first end (10a) of the contact probe (10) comprises a high-hardness material such as rhodium.

22. The probe head (100) further comprises a conductive portion (21) formed on the guide (40), the conductive portion (21) including at least one group (40h') of the guide holes (40h), and configured to contact and short-circuit a corresponding group of contact probes housed in the group (40h') of the holes and intended to transmit a predetermined type of signal, thereby forming a predetermined conductive domain, and at least a portion of the contact probe (10) being in contact with the conductive portion (21), A probe head (100) according to any one of claims 1 to 21.

23. The probe head (100) according to any one of claims 1 to 22, wherein the elastically flexible intermediate section (10s) is structured as a plurality of interconnected elastic elements (10sr') that are connected to one another along the longitudinal axis (H-H) of the contact probe (10), each of the elastic elements (10sr') is configured to be compressed by the action of pressure generated during testing of the device under test, each of the elastic elements (10sr') is configured such that, during the compression, its dimension along the longitudinal axis (H-H) of the contact probe (10) is reduced and its lateral dimension is increased, and the elastic elements (10sr') have an elongated shape along the longitudinal axis (H-H).

24. The probe head (100) according to claim 22 or 23, wherein at least one of the elastic elements (10sr') is configured to contact the conductive portion (21) via its side walls (40W1, 40W2) as its lateral dimension increases during testing of the device under test.

25. The probe head (100) according to any one of claims 1 to 24, wherein the contact probe (10) comprises a stopping means formed on its body (10') and configured to mechanically contact at least a portion of the guide (40) to cause the contact probe (10) to be held in place within the probe head (100).

26. The stopping means comprises a stopper (50) having a lateral extension that defines at least one shoulder portion (S1, S2) configured to abut against the surface (FB) of the guide (40), wherein the surface (FB) is on the opposite side of the surface (FA) of the guide (40) that faces the device under test, and / or The stopping means comprises at least one clip (60) configured to mechanically interfere with the guide hole (40h) and to contact the corresponding wall (40W) of the guide hole (40h), wherein the clip (60) protrudes from the body (10') of the contact probe (10) and is configured to elastically deform while in contact with the wall (40W) of the guide hole (40h), thereby causing the mechanical interference with the guide hole (40h) to hold the contact probe (10) in place, the probe head (100) according to claim 25.

27. The probe head (100) according to claim 26, wherein the contact probe (10) comprises an elastic portion (10pr) disposed between the stopping means, particularly the stopper (50) and its second end (10b), the elastic portion (10pr) being configured to be pre-compressed in a stationary state after the assembly of the probe head (100), and when pre-compressed, being configured to exert a pre-load force (Fpr) at least along the longitudinal axis (H-H).

28. The probe head (100) according to any one of claims 1 to 27, wherein the elastically flexible intermediate section (10s) is embedded in a polymer material (P).

29. The guide (40) comprises a first guide (40a) having a first guide hole (40ah) and a second guide (40b) having a second guide hole (40bh), The elastically flexible intermediate section (10s) is positioned in at least one of the first guide hole (40ah) and the second guide hole (40bh), The contact probe (10) further comprises an intermediate stopping means positioned between the first guide (40a) and the second guide (40b), the intermediate stopping means being configured to mechanically contact at least a portion of the first guide (40a) and / or the second guide (40b) in order to hold the contact probe (10) within the probe head (100). The probe head (100) according to claim 1.

30. The probe head (100) according to claim 29, wherein the intermediate stopping means comprises an intermediate stopper (50') having a lateral extension so as to define at least one shoulder portion (S1', S2') configured to abut against the surface of the first guide (40a) and / or the second guide (40b).

31. The probe head (100) according to claim 29, wherein the intermediate stopping means comprises a retaining element (90) formed as an elastic hook, the retaining element (90) is configured to elastically deform while inserting the contact probe (10) through one of the first guide hole (40ah) or the second guide hole (40bh) and while withdrawing the contact probe (10) through the other of the first guide hole (40ah) and the second guide hole (40bh), the retaining element (90) is configured not to deform when housed between the first guide (40a) and the second guide (40b), and is configured to contact the first guide (40a) and / or the second guide (40b) to hold the contact probe (10).

Images