WO2024006446A1

WO2024006446A1 - Compliant pin probes with extension springs or spring segments and ratcheting elements

Info

Publication number: WO2024006446A1
Application number: PCT/US2023/026590
Authority: WO
Inventors: Ming Ting Wu; Arun S. VEERAMANI
Original assignee: Microfabrica Inc.
Priority date: 2022-06-30
Filing date: 2023-06-29
Publication date: 2024-01-04
Also published as: WO2024006449A1; WO2024006449A4; WO2024025700A9; WO2024025700A1

Abstract

Embodiments are directed to probe structures and/or arrays wherein the probes include at least one spring segment and wherein ratcheting elements on probe arms and/or longitudinal elements allow permanent or semi-permanent transition from a build state or initial state to a working state or pre-biased state.

Description

SPECIFICATION

Title: Compliant Pin Probes with Extension Springs or Spring Segments and Ratcheting Elements

Cross Reference

The present Application for Patent claims priority to U.S. Patent Application No. 17/898,400 by Wu et al., entitled “Compliant Probes with Enhanced Pointing Stability and Including At Least One Flat Extension Spring, Methods for Making, and Methods for Using,” filed August 29, 2022, U.S. Patent Application No. 17/854,756 by Wu et al., entitled “Compliant Pin Probes with Extension Springs, Methods for Making, and Methods for Using,” filed June 30, 2022 and U.S. Patent Application No. 17/898,446 by Wu et al., entitled “Kelvin probes including dual independently operable probe contact elements including at least one flat extension spring,” filed August 29, 2022, each of which is assigned to the assignee hereof, and each of which is expressly incorporated by reference in its entirety herein.

Field of the Invention:

[01] Embodiments of the present invention relate to probes for testing electronic circuits (e.g., for use in the wafer level testing, chip scale package testing, or socket testing of integrated circuits, or for use in making electrical connections to PCBs or other electronic components). In some embodiments, the probes are microprobes, and they may be pin-like probes with spring elements supported by relatively rigid elements wherein the probe heights may be much greater than their lateral dimensions or such dimensions may be comparable. The probes may have single contact elements or multiple contact elements. Embodiments include, or provide, probes having at least one extension spring and may or may not also include one or more compression springs. Probe tips compress toward one another under an elastic return force provided by one or more flat extension springs or segments that provide a return force wherein in some embodiments the extension springs are pre-biased prior to contacting a DUT to be tested and in some embodiments the probe includes relatively movable rigid elements with operational gaps that are smaller than can be generally formed in an assembled state or that have varying gap widths that provide for effective formation as well as stabilized probe operation, while still other embodiments are directed to methods for making probes and/or assembling the probes into probe arrays.

Background of the Invention:

[02] Probes:

[03] Numerous electrical contact probe and pin configurations have been commercially used or proposed, some of which may qualify as prior art while others may not.

[04] Electrochemical Fabrication:

[05] Electrochemical fabrication techniques for forming three-dimensional structures from a plurality of adhered layers have been, and are being, commercially pursued by Microfabrica® Inc. (formerly MEMGen Corporation) of Van Nuys, California under the process names EFAB and MICA FREEFORM®. [06] Various electrochemical fabrication techniques were described in U.S. Patent No. 6,027,630, issued on February 22, 2000, to Adam Cohen.

[07] A related method for forming microstructures using electrochemical fabrication techniques is taught in U.S. Patent No. 5,190,637 to Henry Guckel, entitled “Formation of Microstructures by Multiple Level Deep X-ray Lithography with Sacrificial Metal Layers”.

[08] Electrochemical fabrication provides the ability to form prototypes and commercial quantities of miniature objects, parts, structures, devices, and the like at reasonable costs and in reasonable times. In fact, electrochemical fabrication is an enabler for the formation of many structures that were hitherto impossible to produce. Electrochemical fabrication opens the spectrum for new designs and products in many industrial fields. Even though electrochemical fabrication offers this capability, and it is understood that electrochemical fabrication techniques can be combined with designs and structures known within various fields to produce new structures, certain uses for electrochemical fabrication provide designs, structures, capabilities and/or features not known or obvious in view of the state of the art.

[09] A need exists in various fields for miniature devices having improved characteristics, improved operational capabilities, reduced fabrication times, reduced fabrication costs, simplified fabrication processes, greater versatility in device design, improved selection of materials, improved material properties, more cost effective and less risky production of such devices, and/or more independence between geometric configuration and the selected fabrication process.

Summary of the Invention:

[10] It is an object of some embodiments of the invention to provide improved compliant pin probes (e.g. with barrel and plunger type operation or sheath and double plunger operation) with one or more substantially planar spring segments with at least one of the segments being operated in tension with the probes further including sheaths or other rails, slots, channels, spring connector arms, and/or other engagement structures providing enhanced stability of probe performance.

[11] It is an object of some embodiments of the invention to provide a probe having at least one movable contact tip with an opposite end of the probe having a structure that is to be bonded or attached to an electrical interface, or contact to an electrical interface via a tip that forms part of a probe body, sheath or barrel.

[12] It is an object of some embodiments of the invention to provide a probe with a sheath that has at least one end cap that restrains excessive longitudinal movement of at least one tip from that end of the probe.

[13] It is an object of some embodiments of the invention to provide a probe that has at least two movable contact tips for contacting different electronic components or different pads or bumps on the same electronic component relative to a sheath, barrel or other non-moving portion of the probe.

[14] It is an object of some embodiments of the invention to provide a probe with the sheath having at least two end caps that restrain excessive longitudinal movement of the tips from either end of the probe.

[15] It is an object of some embodiments of the invention to provide a pin-like probe having two tips, with at least one being a contact tip wherein the probe has a configuration that enhances pointing accuracy of the two tips (i.e. reduces lateral misplacement of tips when making contact or undergoing compression and/or reduces angular misalignment of longitudinal elements that hold the tips and allow their longitudinal movement with respect to one another wherein, for example, the configuration provides for reduced gaps or clearance between one or more longitudinal arms or plungers relative to channels or barrels they move through after an initial compression of the tips toward one another (which may be a pre-biasing compression or a compression while in a working state).

[16] It is an object of some embodiments of the invention to provide probes with enhanced pointing accuracy by providing narrowed gaps or clearance at one or more (e.g., starting, periodic, or ending) locations along a length of a channel or barrel relative to an arm or plunger.

[17] It is an object of some embodiments of the invention to provide probes with enhanced pointing accuracy by providing narrowed channel or barrel dimensions at one or more (e.g., starting, periodic, and/or ending) locations along a length of a channel or barrel.

[18] It is an object of some embodiments of the invention to provide probes with enhanced pointing accuracy by providing widened arm or plunger dimensions at one or more (e.g., starting, periodic, or ending) locations along a length of the arm, arms, plunger, or plungers.

[19] It is an object of some embodiments of the invention to form probes on their sides, e.g., with the longitudinal axis of the probe being perpendicular to a normal direction of the planes of layers from which the probes are formed.

[20] It is an object of some embodiments of the invention to form probes on their sides wherein any smooth curved features of the probe are formed within individual layers while changes in probe configuration from layer to layer are provided with stair stepped or at least partially discontinuous transitions.

[21] It is an object of some embodiments of the invention to provide configurations that improve pointing alignment within a single layer, while it is an object of other embodiments to provide configurations that improve pointing alignment via multiple adjacent layers, while it is an object of still other embodiments to provide configurations that improve pointing alignment that are located on non-adjacent layers.

[22] It is an object of some embodiments of the invention to provide a probe that is configured to provide shunting of a majority of the current through a sheath as opposed to through a majority of the length of the spring elements.

[23] It is an object of some embodiments of the invention to provide a probe with a configuration that provides a compliant element attached to the sheath that is in direct or indirect sliding contact with the moving tip.

[24] It is an object of some embodiments of the invention to provide a probe with a configuration that provides a compliant element attached directly or indirectly to the moving tip and is in direct or indirect sliding contact with a sheath.

[25] It is an object of some embodiments of the invention to provide a probe with a sheath that is formed as multiple components, with the components pushed longitudinally together after formation to load the spring segments and to join the multiple components. [26] It is an object of some embodiments of the invention to provide a probe with a joining structure or structures that are configured to allow the moving of a compliant element through an engagement feature that inhibits unjoining.

[27] It is an object of some embodiments of the invention to provide a probe with at least some spring segments that undergo tensional loading when transitioning from a build configuration to a working configuration.

[28] It is an object of some embodiments of the invention to provide transitioning that includes moving a compliant element through an engagement feature that inhibits movement back to a build configuration.

[29] It is an object of some embodiments of the invention to provide probes with sheaths that include one or more ratcheting or stepped locking mechanisms and a fixed extension stop that allow the probe to be formed in a compressed or compacted state (using less batch wafer real estate for a body or sheath portion of the probe) and then two portions of the sheath pulled apart longitudinally to engage the at least one ratcheting mechanism without risk of overextending the springs or sheath components such that the probe is held in an elongated or stretched state with at least one pre-biased extension spring.

[30] It is an object of some embodiments of the invention to provide probes with sheaths that include one or more ratcheting or stepped locking mechanisms, a fixed extension stop as well as a secondary retention lock that allow the probes to be formed in a compressed or compacted state (using less batch wafer real estate for a body or sheath portion of the probe) and then two portions of the sheaths pulled apart longitudinally to engage the at least one ratcheting mechanism and the secondary lock without risk of overextending the springs or sheath components such that the probes are held in an elongated or stretched state with at least one pre-biased extension spring.

[31] It is an object of some embodiments of the invention to provide extension probes with arm- to-spring mounting plates with openings therein that probe tip arms or probe tip extensions can extend, with the probe arms including at least one ratcheting feature that can be formed between the mounting plates and that can be moved beyond the mounting plates to permanently bias at least one extension spring such that during use, the extension spring always has a non-zero initial bias or pre-load.

[32] Other objects and advantages of various embodiments of the invention will be apparent to those of skill in the art upon review of the teachings herein. The various embodiments of the invention, set forth explicitly herein or otherwise ascertained from the teachings herein, may address one or more of the above objects alone or in combination, or alternatively they may address some other object ascertained from the teachings herein. It is not intended that any particular object, let alone all objects, be addressed by any single aspect of the invention.

[33] In a first aspect of the invention, a probe for testing a DUT, includes: (a) a first tip arm connecting directly or indirectly to an attachment region of a first tip for making electrical contact to a first electrical circuit element; (b) a second tip arm connecting directly or indirectly to an attachment region of a second tip; (c) a first stop plate with a first opening, joined directly or indirectly to the first tip arm and a second stop plate with a second opening, joined directly or indirectly to the second tip arm, wherein the first tip arm passes through the second opening of the second stop plate and the second tip arm passes through the first opening of the first stop plate; and (d) a compliant structure comprising at least one spring segment, wherein a first region of the compliant structure joins directly or indirectly the first stop plate and a second region of the compliant structure joins directly or indirectly the second stop plate; wherein relative displacement of the first and second tip arms results in an elastic stretching of the at least one spring segment of the compliant structure and in a movement of the second stop plate away from the first stop plate.

[34] Numerous variations of the first aspect of the invention are possible and include, for example: (1) the compliant structure may comprises a plurality of spring segments; (2) the probe may further comprise a feature selected from a group consisting of: (a) configurations that can engage with features on an array structure to allow for pre-biasing of at least one spring segment, (b) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms; and (c) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms wherein the at least one shunting element is a surface against which the tip arms slide; (3) the probe may further comprise at least one guide structure connected to the first and second tip arms and providing enhanced stability and/or pointing accuracy to the probe and limiting relative movement of the first tip and the second tip along a substantially longitudinal axis of the probe; (4) the second tip may be configured for making an electrical connection to a second circuit element, wherein the configuration is selected from a group consisting of: (a) a tip for making a contact connection, and (b) a tip for making an attached connection; (5) the probe may have a length selected from a group consisting of: (a) less than 2 mm, (b) less than 3 mm, (c) less than 5 mm, (d) less than 8 mm, (e) more than 2 mm, (f) more than 3 mm, (g) more than 5 mm, and (h) more than 8 mm and a width selected from a group consisting of: (a) less than 100 microns, (b) less than 200 microns, (d) less than 300 microns, (d) less than 400 microns, and (e) less than 600 microns; and (6) the probe may be configured in an array for wafer level testing or for socket testing of one or more packaged ICs.

[35] In a second aspect of the invention, a probe fortesting a DUT may further comprise a multipart sheath having at least: a first biasing portion including at least one first lateral element resting on the second stop plate and at least one first longitudinal element protruding from the at least one lateral element; and a second biasing portion including at least one second lateral element resting on the first stop plate and at least one second longitudinal element protruding from the second lateral element toward the first biasing portion, wherein the first and second longitudinal elements of the first and second biasing portion can move at least partially passed one another and include respective first and second ratcheting features, that have different positions with respect to one another while the probe is in a different working condition.

[36] Numerous variations of the second aspect of the invention are possible and include, for example: (1) the working condition may be selected from a group consisting of: (a) a neutral, initial, or as formed, state: (b) an extended, or pre-biased, final working state; (2) the ratcheting feature of the first biasing portion may be at a position selected from a group consisting of: (i) closer to the second stop plate than when in a final position, (ii) further from the first stop plate than when in a final position, and (iii) less centrally, longitudinally located with respect to the first stop plate than when in a final position; (3) the second biasing portion may include at least two second longitudinal elements, both protruding from the second lateral element toward the first biasing portion and defining a space between one another wherein the first longitudinal element of the first biasing portion slides; (4) the second biasing portion may include ratcheting features associated to both second longitudinal elements protruding into the space; (5) the second lateral element of the second biasing portion may have an opening wherein the first longitudinal element of the first biasing portion can pass; (6) the first biasing portion may further comprise an additional lateral element at an opposite end with respect to the first lateral element, the additional lateral element resting against the second lateral element of the second biasing portion in a final working condition of the probe; (7) the second biasing portion may further comprise an additional lateral element at an opposite end with respect to the second lateral element; (8) the additional lateral element of the second biasing portion may rest against the first biasing portion in a final working condition of the probe; (10) the first biasing portion may further comprise a secondary lock feature at an opposite end with respect to the second lateral element and the additional lateral element of the second biasing portion may engage with a further space defined by the secondary lock feature in a final working condition of the probe; (9) the secondary lock feature may be a C-shaped feature having an internal open further space; (10) the ratcheting features may be selected from a group consisting of: (a) deflectable sloped arm latches; (b) deflectable element capable of moving past a rigid feature, (c) series of ratcheting element that move past one another; (d) series of singular ratcheting element that move past one another; (e) inclined metal bristles.

[37] In a second aspect of the invention, at least the second tip arm may holds, directly or indirectly, at least one ratcheting feature and wherein the at least one ratcheting feature can be moved through the first opening of the first stop plate to permanently transition the probe (600; 700) from a neutral state to a pre-biased final working state.

[38] Numerous variations of the second aspect of the invention are possible and include, for example: (1) both the first tip arm and the second tip arm may hold, directly or indirectly, respective ratcheting features and the ratcheting features can be moved through the respective openings of the first and second stop plates to permanently transition the probe from the neutral state to a pre-biased final working state; and (2) the ratcheting features may be selected from a group consisting of: (a) deflectable sloped arm latches; (b) deflectable element capable of moving past a rigid feature, (c) series of ratcheting element that move past one another; (d) series of singular ratcheting element that move past one another; (e) deflectable members moved from tip arms to the stop plates while tip arms carry one or more rigid back stop features. Many further variations are possible and will be understood by those of skill in the art upon reviewing the teachings herein.

[39] Still other aspects of the invention will be understood by those of skill in the art upon review of the teachings herein. Other aspects of the invention may involve combinations of the above noted aspects of the invention. These other aspects of the invention may provide various combinations of the aspects presented above as well as provide other configurations, structures, functional relationships, and processes that have not been specifically set forth above but are taught by other specific teachings set forth herein or by the teachings set forth herein as a whole.

Brief Description of the Drawings: [40] FIGS. 1 A - 1 F schematically depict the formation of a first layer of a structure using adhered mask plating where the blanket deposition of a second material overlays both the openings between deposition locations of a first material and the first material itself.

[41] FIG. 1G depicts the completion of formation of the first layer resulting from planarizing the deposited materials to a desired level.

[42] FIGS. 1 H and 11 respectively depict the state of the process after formation of the multiple layers of the structure and after release of the structure from the sacrificial material.

[43] FIG. 2A, 2B-1 to 2B-3 and FIG. 2C provides a schematic illustration of a probe with a single tensional spring or spring segment provided stop plates movable during probe operation and in some cases a sheath.

[44] FIGS. 3A - 3B, 4A-4B and 5A-5B provide schematic cut views of a sheathed extension spring probe according to several embodiments of the invention along with a blown-up view of a side of the sheath in two different working conditions.

[45] FIGS. 6A - 6B and 7A-7B provide schematic cut views of an extension spring probe according to ither embodiments of the invention in two different working conditions.

Detailed Description of Preferred Embodiments:

[46] Electrochemical Fabrication in General

[47] FIGS. 1 A - 11 illustrate side views of various states in an alternative multi-layer, multimaterial electrochemical fabrication process. FIGS. 1A - 1 G illustrate various stages in the formation of a single layer of a multi-layer fabrication process where a second metal is deposited on a first metal as well as in openings in the first metal so that the first and second metals form part of the layer. In FIG. 1 A, a side view of a substrate 82 having a surface 88 is shown, onto which patternable photoresist 84 is deposited, spread, or cast as shown in FIG. 1 B. In FIG. 1 C, a pattern of resist is shown that results from the curing, exposing, and developing of the resist. The patterning of the photoresist 84 results in openings or apertures 92(a) - 92(c) extending from a surface 86 of the photoresist through the thickness of the photoresist to surface 88 of the substrate 82. In FIG. 1 D, a metal 94 (e.g., nickel) is shown as having been electroplated into the openings 92(a) - 92(c). In FIG. 1 E, the photoresist has been removed (i.e., chemically or otherwise stripped) from the substrate to expose regions of the substrate 82 which are not covered with the first metal 94. In FIG. 1 F, a second metal 96 (e.g., silver) is shown as having been blanket electroplated over the entire exposed portions of the substrate 82 (which is conductive) and overthe first metal 94 (which is also conductive). FIG. 1 G depicts the completed first layer of the structure which has resulted from the planarization of the first and second metals down to a height that exposes the first metal and sets a thickness for the first layer. In FIG. 1 H, the result of repeating the process steps shown in FIGS. 1 B - 1 G several times to form a multi-layer structure is shown where each layer consists of two materials. For most applications, one of these materials is removed as shown in FIG. 1 1 to yield a desired 3-D structure 98 (e.g., component or device) or multiple such structures.

[48] In some variations, the structure may be separated from the substrate. For example, release of the structure (or multiple structures if formed in a batch process) from the substrate may occur when releasing the structure from the sacrificial material, particularly when a layer of sacrificial material is positioned between the first layer of the structure and the substrate. Alternative methods may involve, for example, the use of a dissolvable substrate that may be separated before, during or after removal of the sacrificial material, machining off the substrate before or after removal of the sacrificial material, or use of a different intermediate material that can be dissolved, melted or otherwise used to separate the structure(s) from the substrate before, during, or after removal of the sacrificial material that surround the structure^).

[49] Various embodiments of various aspects of the invention are directed to formation of three- dimensional structures from materials, some, or all, of which may be electrodeposited or electroless deposited (as illustrated in FIGS. 1A - 11). Some of these structures may be formed from a single build level (e.g., a planarized layer) that is formed from one or more deposited materials while others are formed from a plurality of build levels, each including at least two materials (e.g., two or more layers, more preferably five or more layers, and most preferably ten or more layers). In some embodiments, layer thicknesses may be as small as one micron or as large as fifty microns. In other embodiments, thinner layers may be used while in other embodiments, thicker layers may be used, while in still other embodiments, layer thickness may be varied during formation of different levels of the same structure. In some embodiments, microscale structures have lateral features positioned with 0.1 - 10 micron level precision and minimum feature sizes on the order of microns to tens of microns. In other embodiments, structures with less precise feature placement and/or larger minimum features may be formed. In still other embodiments, higher precision and smaller minimum feature sizes may be desirable. In the present application, meso-scale and millimeter-scale have the same meaning and refer to devices that may have one or more dimensions that may extend into the 0.1 - 50 millimeter range, or larger, and features positioned with a precision in the micron to 100 micron range and with minimum feature sizes on the order of several microns to hundreds of microns.

[50] The various embodiments, alternatives, and techniques disclosed herein may form multilayer structures using a single patterning technique on all layers or using different patterning techniques on different layers. For example, various embodiments of the invention may perform selective patterning operations using conformable contact masks and masking operations (i.e. operations that use masks which are contacted to but not adhered to a substrate), proximity masks and masking operations (i.e. operations that use masks that at least partially selectively shield a substrate by their proximity to the substrate even if contact is not made), non-conformable masks and masking operations (i.e. masks and operations based on masks whose contact surfaces are not significantly conformable), adhered masks and masking operations (masks and operations that use masks that are adhered to a substrate onto which selective deposition or etching is to occur as opposed to only being contacted to it), and/or selective patterned deposition of materials (e.g. via extrusion, jetting, or controlled electrodeposition) as opposed to masked patterned deposition . Conformable contact masks, proximity masks, and non-conformable contact masks share the property that they are preformed and brought to, or in proximity to, a surface which is to be treated (i.e., the exposed portions of the surface are to be treated). These masks can generally be removed without damaging the mask or the surface that received treatment to which they were contacted or located in proximity to. Adhered masks are generally formed on the surface to be treated (i.e., the portion of that surface that is to be masked) and bonded to that surface such that they cannot be separated from that surface without being completely destroyed or damaged beyond any point of reuse. Adhered masks may be formed in a number of ways including: (1) by application of a photoresist, selective exposure of the photoresist, and then development of the photoresist, (2) selective transfer of pre-patterned masking material, and/or (3) direct formation of masks from computer-controlled depositions of material. In some embodiments adhered mask material may be used as a sacrificial material for the layer or may be used only as a masking material which is replaced by another material (e.g., dielectric or conductive material prior to completing formation of a layer where the replacement material will be considered the sacrificial material of the respective layer. Masking material may or may not be planarized before or after deposition of material into voids or openings included therein.

[51] Patterning operations may be used in selectively depositing material and/or may be used in the selective etching of material. Selectively etched regions may be selectively filled in or filled in via blanket deposition, or the like, with a different desired material. In some embodiments, the layer-by-layer build up may involve the simultaneous formation of portions of multiple layers. In some embodiments, depositions made in association with some layer levels may result in depositions to regions associated with other layer levels (i.e., regions that lie within the top and bottom boundary levels that define a different layer’s geometric configuration). Such use of selective etching and/or interlaced material deposition in association with multiple layers is described in U.S. Patent Application No. 10/434,519, by Smalley, filed May 7, 2003, which is now US Patent 7,252,861 , and which is entitled “Methods of and Apparatus for Electrochemically Fabricating Structures Via Interlaced Layers or Via Selective Etching and Filling of Voids”.

[52] Temporary substrates on which structures may be formed may be of the sacrificial-type (i.e. destroyed or damaged during separation of deposited materials to the extent that they cannot be reused) or non-sacrificial-type (i.e. not destroyed or excessively damaged, i.e. not damaged to the extent that they may not be reused, e.g. with a sacrificial or release layer located between the substrate and the initial layers of a structure that is formed). Non-sacrificial substrates may be considered reusable, with little or no rework (e.g., replanarizing one or more selected surfaces or applying a release layer, and the like) though they may or may not be reused for a variety of reasons.

[53] Definitions of various terms and concepts that may be used in understanding the embodiments of the invention (either forthe devices themselves, certain methods for making the devices, or certain methods for using the devices) will be understood by those of skill in the art.

[54] Probe Embodiments:

[55] Probes of the various embodiments of the invention can take on a variety of forms. Each probe includes at least one substantially flat tensional spring segment that biases a test contact tip relative to a second tip that may or may not be a contact tip wherein the probes generally include structural elements for ensuring stable and robust probe functionality. In some embodiments, the probes further include a plurality of substantially flat spring segments, either of the extension type only or of a combination of one or more extension springs and one or more compression springs. In some embodiments, springs are configured to operate functionally in series or in parallel with the spring segments at least partially lying side- by-side or face-to-face as opposed to edge-to-edge or end-to-end. In some embodiments, probe deformation is limited to a compression along the axis of the probe (e.g., substantially longitudinal compression as probe tips or circuit joining elements move to more proximal positions). [56] Numerous other variations are possible, some of which are explicitly or implicitly set forth herein while others will be apparent to those of skill in the art after review of the teachings herein. Some variations include using such probes in testing integrated circuits, dies on semiconductor wafers, or other electronic circuits. Other variations include assembly of a plurality of such probes into arrays for use in testing applications or for use in permanent contact applications. Further embodiments include methods for making such probes or making such arrays.

[57] Reference numbers are included in many of the figures wherein like numbers are used to represent similar structures or features in different embodiments.

[58] First Group of Embodiments: Probe with Extension Spring or Sprigs held within Sheath

[59] FIG. 2A provides a schematic illustration of a probe 200A with a single tensional spring or spring segment 201 connected on either end to two tip arms, in particular an upper tip arm 211 and a lower tip arm 212 with corresponding upper and lowertips 21 1T and 212T. In particular, the upper and lower tip arms 21 1 , 212 are connected to the spring segment 201 via respective movable stop plates or lateral arms, in particular, an upper stop plate 264 and a lower stop plate 262, a lower portion of the upper tip arm 211 connecting to the lower stop plate 262 and an upper portion of the lower tip arm 212 connecting to the upper stop plate 464. Suitably, the upper stop plate 264 has an opening 202-1 and the lower stop plate 262 has an opening 402-2 through which the upper tip arm 211 and the lower tip arm 212 can pass freely, respectively, the walls of the openings 202-1 and 202-2 functioning as longitudinal movement guide elements for the tip arms. Here and below, relative terms like “top", “bottom, “upper” “lower” and similar ones are intended as referring to the illustrations given in the drawings, for sake of conciseness. Similarly, terms like “left” and “right will be used still with reference to the drawings.

[60] FIGS. 2B-1 to 2B-3 provide schematic illustrations of a probe 200B, similar to probe 200A of FIG. 2A, with the probe further including a sheath or frame structure 235 with a left side and right side being shown. In particular, the sheath or frame structure 235 sets a minimum distance between the upper and lower stop plates 264 and 262 with the sheath 235 suitably including at least upper stop features 232-1 , lower stop features 232-2, and spacer or standoff sections 234. FIG. 2B-1 shows the probe 200B in an undeflected state with the movable stop plates 262, 264 resting against the upper and lower stop features 232-1 and 232-2 of the sheath 235, respectively. FIG. 2B-2 shows the probe 200B with the lower tip 212T compressed toward the sheath 235 (e.g., by contact with a lower contact structure 250, for instance an electrical circuit element like a device under test DUT, that is moved toward the bottom of the sheath 235) with the spring segment 201 being biased or stretched as the movable upper stop plate 264 is forced away from the top of the sheath 235. FIG. 2B-3 shows the probe 200B after the upper tip 211T is compressed toward the sheath 235 (e.g., by contact with an upper contact structure 255, for instance an electronic circuit element like a test circuitry, in particular a space transformer or a PBC connecting the test circuitry, that is moved toward the top of the sheath 235) with the spring segment 201 being further biased or stretched as the movable lower stop plate 262 is forced away from the lower portion of the sheath 235.

[61] In particular, the relative displacement of the upper and lower tip arms 211 , 212 results in an elastic stretching of the spring segment 201 and in a movement of the upper stop plate 264 away from the lower stop plate 262. [62] In some embodiments, the sheath 235 may be provided with solid front and back faces or front and back frame structures that help provide lateral guidance during movement of the stop plates 262, 264. In some embodiments, the sheath 235 and/or the movable stop plates 262, 264 may include additional features that allow for retention of relative lateral positions during longitudinal movement of the tip arms 211 , 212, connected stop plates 262, 264, and spring segment 201 relative to the sheath 235.

[63] FIG. 2C provides another schematic illustration of a probe 400C, similar to probe 400A of FIG. 4A, with the spring segment 201 being pre-biased by use of a taller sheath or frame structure 235 that holds the movable upper and lower stop plates 264, 262 at a larger relative separation, thus ensuring that an initial contact of either upper or tip 211T, 212T against a surface (e.g. a pad, bump, or other contact surface of an electrical circuit element) will be accompanied by a non-zero restoration or back force.

[64] -Second Group of Embodiments: Probe with Extension Spring or Spring Segment held within a Sheath provided with Ratchetable Features

[65] FIGS. 3A - 3B provide a schematic cut view of a sheathed extension spring probe 300 along with a blown-up view of a side of a sheath 335 comprised therein and being a multi-part sheath. More particularly, FIG. 3A shows the extension spring probe 300 in a first working condition, corresponding to a neutral, initial, or as formed, state along with a blown up view of a side of the sheath 335 and FIG. 3B shows the extension spring probe 300 in a second working condition, corresponding to an extended, or pre-biased, final working state, along with a blown up view of a side of the sheath 335.

[66] The extension spring probe 300 of FIGS. 3A and 3B is similar to the probe 200B of

FIGS. 2B-1 to 2B-3 and comprises a single tensional spring segment 301 connected on either end to two tip arms 31 1 and 312 with corresponding tips 311T and 312T via respective stop plates or lateral arms 362 and 364, the sheath 335 setting a minimum distance between the lower stop plates 362 and the upper stop plate 364. In particular, a lower portion of the upper tip arm 311 connects to a lower stop plate 362 and an upper portion of the lower tip arm 312 connects to the upper stop plate 364. Moreover, the upper stop plate 364 has an opening 302-1 and the lower stop plate 362 has an opening 302-2 through which the respective upper and lower tip arm 31 1 , 312 can pass freely with the walls of the openings functioning as longitudinal movement guide elements. As previously explained, the lower tip 312T can be punt into contact with a lower contact structure, for instance an electrical circuit element like a device under test DUT, that is moved toward the bottom of the sheath 335 and the upper tip 231 T may be put into contact with an upper contact structure, for instance an electronic circuit element like a test circuitry, in particular a space transformer or a PBC connecting the test circuitry, that is moved toward the top of the sheath 335, with the spring segment 301 being stretched accordingly.

[67] As shown in FIGS. 3A and 3B, the sheath 335 comprises two identical side 340, each side 340 comprising two movable biasing portions or handles, in particular, at least a first or upper handle 350 and a second or lower handle 370, disposed between the upper stop plate 364 and the lower stop plate 362 and being configured so as to slid one with respect to the other. More particularly, the upper handle 350 comprises at least a lateral arm or stop element 352 which rests against the upper stop plate 364 as well as a longitudinal element 354 protruding from the stop element 352 toward the lower handle 370, which in turn comprises at least a lateral arm or stop element 372 which rests against the lower stop plate 362 as well as at least two longitudinal element 374-1 and 374-2 protruding from the stop element 372 toward the upper handle 350 and defining a space 380 between one another wherein the longitudinal element 354 of the upper handle 350 slides.

[68] Suitably, each side 340 of the sheath 335 includes ratchetable or interlaced features which engage when the sheath 335 initially undergoes an expansion from an initial working state (which may be an as formed state or a less biased working state) as shown in FIG. 3A to the pre-biased final working state as shown in FIG. 3B. In particular, the upper handle 350 and the lower handle 370 comprise respective ratchetable or interlaced features 356 and 376, for instance in the form of inclined features such as deflectable sloped arm latches or inclined metal bristles as illustrated, suitably associated with their longitudinal elements 354, 374-1 and 374-2 so as to engage one another when the upper and lower handles 350, 370 move one respect the other, the longitudinal elements 354, 374-1 and 374-2 moving at least partially passed one another, as shown in FIG. 3B.

[69] After batch formation of a plurality of probes, the probes may be individually released or released in as groups (e.g., tethered groups). After release of the probes in groups, or as individual probes, the probes may be placed in fixtures that hold the probes in a desired orientation and then the upper handles or other features on the upper portion of the sheath may be manipulated in relation to the lower handles or other features on the lower portion of the sheath such that the upper and lower portions move apart to engage the ratcheting features so that the spring of the probe becomes permanently biased and the sheath becomes permanently elongated.

[70] In particular, the ratcheting feature 356 of the upper handle 350 may be at a position selected from a group consisting of: (i) closer to the upper stop plate 364 than when in the final position, (ii) further from the lower stop plate 362 than when in a final position, and (iii) less centrally, longitudinally located with respect to the lower stop plate 362 than when in the final position.

[71] FIGS. 4A - 4B provide a schematic cut view of a sheathed extension spring probe 400 comprising at least a spring segment 401 and a sheath 435, along with a blown-up view of a side of the sheath 435, still being a multi-part sheath with two identical but specular sides 440. As previously, FIG. 4A shows the extension spring probe 400 in a first working condition, corresponding to a neutral, initial, or as formed, state along with a blown up view of a side of the sheath 435 and FIG. 3B shows the extension spring probe 400 in a second working condition, corresponding to an extended, or pre-biased, final working state, along with a blown up view of a side of the sheath 435.

[72] Each side 440 of the sheath 435 comprises two movable handles, in particular, at least a first or upper handle 450 and a second or lower handle 470, disposed between an upper stop plate 464 and a lower stop plate 462 and being configured so as to slid one with respect to the other.

[73] More particularly, the upper handle 450 comprises at least a first or upper lateral arm or stop element 452-1 which rests against the upper stop plate 464 as well as a longitudinal element 454 protruding from the upper stop element 452-1 toward the lower handle 470. The upper handle 450 also comprises a second or lower lateral arm or stop element 452-2 which rests against the lower handle 470 in the final working condition of the probe 400. [74] The lower handle 470 in turn comprises at least a lower lateral arm or stop element 472-1 which rests against the lower stop plate 462 as well as at least two longitudinal element 474-1 and 474-2 protruding from the lower stop element 472-1 toward the upper handle 450 and defining a space 480 between one another wherein the longitudinal element 454 of the upper handle 450 slides. According to the alternative embodiment of FIG. 4A and 4B, the lower stop element 472-1 of the lower handle 460 has an opening 478 so that the longitudinal element 454 of the upper handle 450 can pass the lower stop element 472-1 of the lower handle 470 and the lower stop element 452-2 of the upper handle 450 can rest against the lower stop element 472-1 of the lower handle 470, indeed, in the final working condition of the probe 400.

[75] Moreover, the lower handle 470 comprises an upper later arm or stop element 472-2, at an opposite end with respect to the lower stop element 472-1 , the upper stop element 472-2 resting on the upper stop element 452-1 of the upper handle in the final working condition of the probe 400, as shown in FIG. 4B.

[76] Suitably, each side 440 of the sheath 435 includes ratchetable or interlaced features which engage when the sheath 435 initially undergoes an expansion from an initial working state (which may be an as formed state or a less biased working state) as shown in FIG. 4A to the pre-biased final working state as shown in FIG. 4B. In particular, the upper handle 450 and the lower handle 470 comprise respective ratchetable or interlaced features 456 and 476 engaging one another when the upper and lower handles 450, 470 move one respect the other.

[77] In a manner similar to that discussed above with regard to FIGS. 3A - 3B, pre-biasing of the spring segments 401 and sheaths 435 may occur but instead of by pulling on handles 450, 470, the longitudinal elements of the lower portion and r portion of the sheath may be pushed toward one another to engage the ratcheting features so that the spring segment 401 of the probe 400 becomes permanently biased and the sheath 435 becomes permanently extended.

[78] FIGS. 5A - 5B provide a schematic cut view of a sheathed extension spring probe 500 along with a blown-up view of a side of its sheath 535 according to another embodiment of the present invention. FIG. 5A shows the extension spring probe 500 in a first working condition, corresponding to a in a neutral, initial, or as formed state along with a blown up view of a side of the sheath 535 and FIG. 5B shows the extension spring probe 500 in a second working condition, corresponding to an extended, or pre-biased, final working state, along with a blown up view of a side of the sheath 535.

[79] With respect to the embodiment of FIGS. 5A and 5B, the upper handle 540 comprises a secondary lock feature in the form of a C-shaped end 552C at its upper stop element 552-1 , defining a further space 580-2 wherein the upper stop element 572-2 of the lower handle 570 can engage, as shown in FIG. 5B, when the sheath 535 initially undergoes an expansion from the initial state to the pre-biased final working state, additionally with respect to the engagement of the ratchetable or interlaced features 556 and 576 of the longitudinal elements 554, 574-1 and 574-2 of the upper and lower handles 550, 570, respectively.

[80] Like the embodiment of FIGS. 4A - 4B, pre-biasing of the spring segments 501 and sheaths 535 of this embodiment may occur by pulling on handles 540, 570 or instead by the longitudinal elements of the lower portion and upper portion of the sheath 535 being pushed toward one another to engage the ratcheting features so that the spring segment 501 of the probe 500 becomes permanently biased and the sheath 535 becomes permanently extended.

[81] Third Group of Embodiments: Probe with Extension Spring or Spring Segment provided with Ratchetable Features

[82] FIGS. 6A - 6B provide schematic cut views of an extension spring probe 600 according to a further embodiment of the invention, in a first working condition corresponding to a neutral, initial, or as formed state (FIG. 6A) and in a second working condition corresponding to an extended, or pre-biased, final working state (FIG. 6B). According to this embodiment, the upper and lower tip arms 611 , 612 of the probe 600 each include ratchetable features 640-1 and 640-2, respectively, that can be moved through openings 602-1 , 602-2 provided in the upper and lower stop plates 664, 662 to permanently transition from the neutral state or initial state to a pre-biased final working state. Since the tip arms 611 , 612 of the probes 600 hold the ratchetable features 640-1 and 640-2 in this embodiment, permanent pre-biasing of the spring segments 601 may occur simply by pressing the upper and lower probe tips 611T, 612T together. According to an alternative embodiment, the final configuration may be achieved while a plurality of probes is located in a laterally spaced array configurations or where the probes will be assembled into their lateral array configurations after the pre-biasing of their springs have been completed.

[83] FIGS. 7A - 7B provide a schematic cut view of an extension spring probe 700 according to yet another embodiment of the invention, in a first working condition corresponding to a neutral, initial, or as formed state (FIG. 7A) and in a second working condition corresponding to an extended, or pre-biased, final working state (FIG. 7B). According to this alternative embodiment, only one tip arm, for instance the lower tip arm 711 , includes a ratchetable feature 740 that can be moved through an opening 702-2 in a lower stop plate 762 to permanently transition the probe 700 from the neutral state to the pre-biased final working state. The probe 700 and the pre-biasing of the spring segment is similar to that of the prior embodiment with the exception that the ratcheting elements are not provided on both tip arms but instead on only a single one of the tip arms.

[84] Numerous variations of the ratcheting or locking based pre-biasing embodiments of FIGS. 3A - 3B are possible and may involve the ratcheting elements taking on different configurations than the deflectable sloped arm latches that were illustrated, such as for example, ratcheting pairs may include a deflectable element that is capable of moving past a rigid feature, instead of a series of ratcheting element that move past one another, the ratcheting elements may be singular in nature. In the embodiments of FIGS. 6A-6B and 7A-7B, the ratcheting elements can be in the form of deflectable members that may be moved from the tip arms to the plates while the tip arms carry one or more rigid back stop features.

[85] Suitably, the probe according to anyone of the above described embodiments may have a length selected from a group consisting of: (1) less than 2 mm, (2) less than 3 mm, (3) less than 5 mm, (4) less than 8 mm, (5) more than 2 mm, (6) more than 3 mm, (7) more than 5 mm, and (8) more than 8 mm and a width selected from a group consisting of: (1) less than 100 microns, (2) less than 200 microns, (3) less than 300 microns, (4) less than 400 microns, and (5) less than 600 microns.

[86] The probe may be is configured in an array for wafer level testing or for socket testing of one or more packaged integrated circuits. [87] The probe according to anyone of the above described embodiments may also have a compliant structure comprising a plurality of joined spring segments.

[88] According to other embodiments, the probe may further comprise a feature selected from a group consisting of: (1) configurations that can engage with features on an array structure to allow for prebiasing of at least one spring segment, (2) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms; and (3) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms wherein the at least one shunting element is a surface against which the tip arms slide. The probe may be further provided with a guide structure connected to the first and second tip arms and providing enhanced stability and/or pointing accuracy to the probe and limiting relative movement of the first tip and the second tip along a substantially longitudinal axis of the probe.

[89] Still other embodiments may be created by combining the various embodiments and their alternatives with other embodiments and their alternatives as set forth herein.

[90] Further Comments and Conclusions

[91] Various other embodiments of the present invention exist. Some of these embodiments may be based on a combination of the teachings herein with various known teachings. For example, some fabrication embodiments may not use any blanket deposition process. Some embodiments may use selective deposition processes or blanket deposition processes on some layers that are not electrodeposition processes. Some embodiments may use nickel or nickel-cobalt as a structural material while other embodiments may use different materials. For example, preferred spring materials include nickel (Ni), copper (Cu) in combination with one or more other materials, beryllium copper (BeCu), nickel phosphorous (Ni-P), tungsten (W), aluminum copper (Al-Cu), steel, P7 alloy, palladium, palladium-cobalt, silver, molybdenum, manganese, brass, chrome, chromium copper (Cr-Cu), and combinations of these. Some embodiments may use copper as the structural material with or without a sacrificial material.

[92] Structural or sacrificial dielectric materials may be incorporated into embodiments of the present invention in a variety of different ways. Such materials may form a third material or higher deposited material on selected layers or may form one of the first two materials deposited on some layers.

[93] Some embodiments may employ diffusion bonding or the like to enhance adhesion between successive layers of material or to reduce stress.

[94] Various other embodiments of the present invention exist. Some of these embodiments may be based on a combination of the teachings herein with various known teachings. Some methods of making embodiments may not use any blanket deposition process and/or they may not use a planarization process. Some embodiments may use selective deposition processes or blanket deposition processes on some layers that are not electrodeposition processes. Some embodiments, for example, may use nickel, nickelphosphorous, nickel-cobalt, palladium, palladium-cobalt, gold, copper, tin, silver, zinc, solder, rhodium, rhenium as structural materials while other embodiments may use different materials. Some embodiments, for example, may use copper, tin, zinc, solder or other materials as sacrificial materials. Some embodiments may use different structural materials on different layers or on different portions of single layers. Some embodiments may remove a sacrificial material while other embodiments may not. Some embodiments may use photoresist, polyimide, glass, ceramics, other polymers, and the like as dielectric structural materials.

[95] It will be understood by those of skill in the art that additional operations may be used in variations of the above presented method of making embodiments. These additional operations may, for example, perform cleaning functions, and they may perform activation functions and monitoring functions, and the like.

[96] It will also be understood that the probe elements of some aspects of the invention may be formed with processes which are very different from the processes set forth herein, and it is not intended that structural aspects of the invention need to be formed by only those processes taught herein or by processes made obvious by those taught herein.

[97] Though various portions of this specification have been provided with headers, it is not intended that the headers be used to limit the application of teachings found in one portion of the specification from applying to other portions of the specification. For example, alternatives acknowledged in association with one embodiment are intended to apply to all embodiments to the extent that the features of the different embodiments make such applications functional and do not otherwise contradict or remove all benefits of the adopted embodiment. Various other embodiments of the present invention exist. Some of these embodiments may be based on a combination of the teachings set forth herein with various known teachings.

[98] It is intended that any aspects of the invention set forth herein represent independent invention descriptions which Applicant contemplates as full and complete invention descriptions that Applicant believes may be set forth as independent claims without need of importing additional limitations or elements, from other embodiments or aspects set forth herein, for interpretation or clarification other than when explicitly set forth in such independent claims once written. It is also understood that any variations of the aspects set forth herein represent individual and separate features that may form separate independent claims, be individually added to independent claims, or added as dependent claims to further define an invention being claimed by those respective dependent claims should they be written.

[99] In view of the teachings herein, many further embodiments, alternatives in design and uses of the embodiments of the instant invention will be apparent to those of skill in the art. As such, it is not intended that the invention be limited to the particular illustrative embodiments, alternatives, and uses described above but instead that it be solely limited by the claims presented hereafter.

Claims

1 . A probe for testing a DUT, comprising:

(a) a first tip arm (211 ; 311 ; 411 ; 511 ; 611 ; 711) connecting directly or indirectly to an attachment region of a first tip (211 T; 311 T; 41 1T; 511T; 611T; 711 T) for making electrical contact to a first electrical circuit element;

(b) a second tip arm (212; 312; 412; 512; 612; 712) connecting directly or indirectly to an attachment region of a second tip (212T; 312T; 412T; 512T; 612T; 712T).

(c) a first stop plate (262; 362; 462; 562; 662; 762) with a first opening (202-2; 302-2; 402-2; 502-2; 602-2; 702-2), joined directly or indirectly to the first tip arm (211 ; 311 ; 411 ; 511 ; 61 1 ; 711) and a second stop plate (264; 364; 464; 564; 664; 764) with a second opening (202-1 ; 302-1 ; 402-1 ; 502-1 ; 602- 1 ; 702-1), joined directly or indirectly to the second tip arm (212; 312; 412; 512; 612; 712), wherein the first tip arm (211 ; 311 ; 411 ; 511 ; 611 ; 711) passes through the second opening (202-1 ; 302-1 ; 402-1 ; 502-1 ; 602-1 ; 702-1) of the second stop plate (264; 364; 464; 564; 664; 764) and the second tip arm (212; 312; 412; 512; 612; 712) passes through the first opening (202-2; 302-2; 402-2; 502-2; 602-2; 702-2) of the first stop plate (262; 362; 462; 562; 662; 762); and

(d) a compliant structure comprising at least one spring segment (201 ; 301 ; 401 ; 501 ; 601 ; 701), wherein a first region of the compliant structure joins directly or indirectly the first stop plate (262; 362; 462; 562; 662; 762) and a second region of the compliant structure joins directly or indirectly the second stop plate (264; 364; 464; 564; 664; 764), wherein relative displacement of the first and second tip arms (211 , 212; 311 , 312; 411 , 412; 511 , 512; 611 , 612; 711 , 712) results in an elastic stretching of the at least one spring segment (201 ; 301 ; 401 ; 501 ; 601 ; 701) of the compliant structure and in a movement of the second stop plate (264; 364; 464; 564; 664; 764) away from the first stop plate (262; 362; 462; 562; 662; 762).

2. The probe of claim 1 further comprising a multi-part sheath (335; 435; 535) having at least: a first biasing portion (350; 450; 550) including at least one first lateral element (352; 452-1 ;

552-1) resting on the second stop plate (364; 464; 564) and at least one first longitudinal element (354; 454; 554) protruding from the at least one lateral element (352; 452-1 ; 552-1); and a second biasing portion (370; 470; 570) including at least one second lateral element (372; 472-1 ; 572-1) resting on the first stop plate (362; 462; 562) and at least one second longitudinal element (374-1 , 374-2; 474-1 , 474-2; 574-1 , 574-2) protruding from the second lateral element (372; 472-1 ; 572-1) toward the first biasing portion (350; 450; 550), wherein the first and second longitudinal elements (354, 374-1 , 374-2; 454, 474-1 , 474-2; 554, 574-1 , 574-2) of the first and second biasing portion (350, 370; 450, 470; 550, 570) can move at least partially passed one another and include respective first and second ratcheting features (354, 356; 454, 456; 554, 556), that have different positions with respect to one another while the probe is in a different working condition.

3. The probe of claim 2 wherein the working condition is selected from a group consisting of: (1) a neutral, initial, or as formed, state: (2) an extended, or pre-biased, final working state.

4. The probe of claim 2 wherein the ratcheting feature (356; 456; 556) of the first biasing portion (350; 450; 550) are at a position selected from a group consisting of: (i) closer to the second stop plate (364; 464; 564) than when in a final position, (ii) further from the first stop plate (362; 462; 562) than when in a final position, and (iii) less centrally, longitudinally located with respect to the first stop plate (362; 462; 562) than when in a final position.

5. The probe of claim 2 wherein the second biasing portion (370; 470; 570) includes at least two second longitudinal elements (374-1 , 374-2; 474-1 , 474-2; 574-1 , 574-2), both protruding from the second lateral element (372; 472-1 ; 572-1) toward the first biasing portion (350; 450; 550) and defining a space (380; 480; 580) between one another wherein the first longitudinal element (354; 454; 554) of the first biasing portion (350; 450; 550) slides.

6. The probe of claim 5 wherein the second biasing portion (370; 470; 570) includes ratcheting features (354; 454; 554) associated to both second longitudinal elements (374-1 , 374-2; 474-1 , 474-2; 574-1 , 574-2) protruding into the space (380; 480; 580).

7. The probe of claim 2 wherein the second lateral element (472-1 ; 572-1) of the second biasing portion (470; 570) has an opening (478; 578) wherein the first longitudinal element (454; 554) of the first biasing portion (450; 550) can pass.

8. The probe of claim 7 wherein the first biasing portion (450) further comprises an additional lateral element (452-2) at an opposite end with respect to the first lateral element (452-1), the additional lateral element (452-2) resting against the second lateral element (472-1) of the second biasing portion (470) in a final working condition of the probe.

9. The probe of claim 2 wherein the second biasing portion (470; 570) further comprises an additional lateral element (472-2; 572-2) at an opposite end with respect to the second lateral element (472- 1 ; 572-1).

10. The probe of claim 9 wherein the additional lateral element (472-2; 572-2) of the second biasing portion (470; 570) rests against the first biasing portion (470; 570) in a final working condition of the probe.

11 . The probe of claim 9 wherein the first biasing portion (550) further comprises a secondary lock feature (552C) at an opposite end with respect to the second lateral element (572-1) and the additional lateral element (572-2) of the second biasing portion (570) engages with a further space (580-2) defined by the secondary lock feature (552C) in a final working condition of the probe.

12. The probe of claim 11 wherein the secondary lock feature (552C) is a C-shaped feature having an internal open further space (580-2).

13. The probe of claim 2 wherein the ratcheting features (356, 376; 456, 476; 556, 576; 640-1 , 640-2; 740) are selected from a group consisting of: (a) deflectable sloped arm latches; (b) deflectable element capable of moving past a rigid feature, (c) series of ratcheting element that move past one another; (d) series of singular ratcheting element that move past one another; (e) inclined metal bristles.

14. The probe of claim 1 wherein at least the second tip arm (612; 712) holds, directly or indirectly, at least one ratcheting feature (640-2; 740)and wherein the at least one ratcheting feature (640-2; 740) can be moved through the first opening (602-2; 702-2) of the first stop plate (662; 762) to permanently transition the probe (600; 700) from a neutral state to a pre-biased final working state.

15. The probe of claim 14 wherein both the first tip arm and the second tip arm (611 , 612) hold, directly or indirectly, respective ratcheting features (640-2, 640-1) and wherein the ratcheting features (640-2 640-1) can be moved through the respective openings (602-1 , 602-2) of the first and second stop plates (664, 662) to permanently transition the probe (600) from the neutral state to the pre-biased final working state.

16. The probe of claim 14 wherein the ratcheting features (356, 376; 456, 476; 556, 576; 640-1 , 640-2; 740) are selected from a group consisting of: (a) deflectable sloped arm latches; (b) deflectable element capable of moving past a rigid feature, (c) series of ratcheting element that move past one another; (d) series of singular ratcheting element that move past one another; (e) deflectable members moved from tip arms to the stop plates while tip arms carry one or more rigid back stop features.

17. The probe of claim 1 wherein the compliant structure comprises a plurality of spring segments.

18. The probe of claim 1 further comprising a feature selected from a group consisting of: (1) configurations that can engage with features on an array structure to allow for pre-biasing of at least one spring segment, (2) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms; and (3) at least one shunting element that directs current from one of the first or second tip arms through a non-compliant structure and then through the other of the first or second tip arms wherein the at least one shunting element is a surface against which the tip arms slide.

19. The probe of claim 1 further comprising at least one guide structure connected to the first and second tip arms and providing enhanced stability and/or pointing accuracy to the probe and limiting relative movement of the first tip and the second tip along a substantially longitudinal axis of the probe.

20. The probe of claim 1 , wherein the second tip (212T; 312T; 412T; 512T, 612T; 712T) is configured for making an electrical connection to a second circuit element, wherein the configuration is selected from a group consisting of: (1) a tip for making a contact connection, and (2) a tip for making an attached connection.

21 . The probe of claim 1 wherein the probe has a length selected from a group consisting of: (1) less than 2 mm, (2) less than 3 mm, (3) less than 5 mm, (4) less than 8 mm, (5) more than 2 mm, (6) more than 3 mm, (7) more than 5 mm, and (8) more than 8 mm and a width selected from a group consisting of: (1) less than 100 microns, (2) less than 200 microns, (3) less than 300 microns, (4) less than 400 microns, and (5) less than 600 microns.

22. The probe of claim 1 wherein the probe is configured in an array for wafer level testing or for socket testing of one or more packaged integrated circuits.