Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/06711—Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
  • G01R1/06716—Elastic
  • G01R1/06722—Spring-loaded
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/06711—Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
  • G01R1/06733—Geometry aspects
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/06711—Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
  • G01R1/06733—Geometry aspects
  • G01R1/06738—Geometry aspects related to tip portion
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/06711—Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
  • G01R1/06733—Geometry aspects
  • G01R1/0675—Needle-like

Definitions

• Embodiments of the present disclosure relate to microprobes (e.g., for use in the wafer level testing or socket testing of integrated circuits, or for use in making electrical connections to printed circuit boards (PCBs) or other electronic components) and more particularly to pin-like microprobes (i.e., microprobes that have vertical or longitudinal heights that are much greater than their widths).
• the microprobes are produced by electrochemical fabrication methods and more particularly by multi-layer multi-material electrochemical fabrication methods.
• Electrochemical fabrication techniques for forming three-dimensional structures from a plurality of adhered layers are being commercially pursued by Microfabrica Inc. (formerly MEMGen Corporation) of Van Nuys, California under the process names EFAB and MICA FREEFORMTM.
• 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 new 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.
• pin probes e.g., pogo pin probes
• a probe for making electrical contact to an electronic circuit element includes a pin element, comprising a first contact tip and a second contact tip; a compliant biasing member having a first end functionally connected to the first contact tip, and a second end functionally connected to the second contact tip; at least one of the first contact tip and the second contact tip being a movable contact tip connected to the compliant biasing member during its movement; and a guide structure coupled to the compliant biasing member so as to bias movement of the compliant biasing member without significantly restricting a compliance of the compliant biasing member along a longitudinal axis of the probe extending from the first contact tip to the second contact tip, wherein the guide structure is selected from a group consisting of: (i) at least a sheath which encases at least the compliant biasing member along the longitudinal axis of the probe; (ii) an inner sheath which encases the compliant biasing member, an outer sheath which surrounds and is spaced from
• the guide structure may be configured to inhibit non-longitudinal compression of the compliant biasing member; (2) the guide structure may be configured to limit the movement of the compliant biasing member in at least one axis perpendicular to the longitudinal axis of the probe; (3) the compliant biasing member may be a compliant portion of the pin element extending along the longitudinal axis of the probe between the first contact tip and the second contact tip; (4) the probe may further comprise pin sleeves able to guide the at least one movable contact tip during its movement; (5) the pin sleeves may be formed by suitably shaped end portion of the guide structure in correspondence of the at least one movable contact tip; (6) the pin sleeves may be connected to the guide structure in correspondence of the at least one movable contact tip by respective dielectric spacers, a combination of the pin sleeves and dielectric spacers forming a retainment structure of the at least one movable contact tip; (7) the probe may further comprise a
• a rigid intermediate region may exist where extending from the rigid intermediate region at least one compliant sliding contact element exists that provides a conductive path between the first contact tip, a body of the sheath, and the second tip when the first contact tip is compressed toward the second contact tip;
• the at least one compliant sliding contact element may include two oppositely oriented compliant sliding contact elements that provide compliant contact the sheath;
• the sliding contact elements may be not forced into contact with the sheath when no compression of the first tip toward the second tip exists;
• at least one of the first contact tip or the second tip may include a curved contact in at least one dimension that is configured to provide stable mating with a bumped contact on an electronic component;
• the sheath may be an inner sheath that is electrically isolated from an outer sheath and can slide relative to the outer sheath when the second tip makes contact with an electronic circuit element:
• the probe may comprise a first pin element having a
• FIGS. 1A - 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.
• FIG. 1G depicts the completion of formation of the first layer resulting from planarizing the deposited materials to a desired level.
• 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.
• FIGS. 2A - 2R provide various views of a sample coaxial pin-probe according to an embodiment wherein the pin probe includes a pin element that is biased to move within a rigid guide member comprising a first conductive sheath which is separated from a second surrounding conductive sheath by dielectric spacers.
• FIGS. 3A - 30 provide various views of a sample pin probe including a pin element and a rigid guide member comprising a sheath that can shunt current from a moveable tip at one end of the pin element to the sheath and then to a fixed tip at the other end of the probe.
• FIGS. 4A - 4H provide various views of another sample pin probe including a pin element and a rigid guide member, the sample pin probe having a single movable contact tip and fixed tip with a stacked buckled plate-like spring configuration.
• FIGS. 5A - 51 provides another sample pin probe with a single movable contact tip and a fixed tip with another alternative spring configuration including a pair of serpentine springs located on either side of a rigid guide member wherein the pin element includes a fabrication position that is different from a use position wherein the movable pin moves from the fabrication position to the use position via movement past a compliant engagement element that inhibits the tip from extending from a useable range back to the fabrication position after initial loading.
• FIGS. 6A - 6B provides another sample pin probe including a pair of electrically isolated pin elements that include movable contact tips on one side and fixed tips on the other wherein the movable contact tips are rigidly joined for coincident movement or are loosely joined for substantially coincident movement for Kelvin type probe, the sample pin probe including a rigid guide member comprising a pair of sheaths surrounding the pair od pin elements.
• FIGS. 7 A - 7H provide various views of a shielded pseudo coaxial probe according to another embodiment of the disclosure that includes a central conductor as pin element and a fixed length shielding conductor as rigid guide member, wherein the central conductor includes lower and upper fixed length surfaces connected to the shield conductor by dielectric spacers.
• FIGS. 8A - 8C depict a spring comprising a plurality of S-shaped segments (FIG. 8A) that may be used in various embodiments of the disclosure.
• FIGS. 10A - 10D provide another example of a pseudo coaxial probe but where only one end has significant compliance.
• FIGS. 11 A - 111 provide various views of an embodiment similar to that of FIGS. 10A - 10D with the primary exception being that the probe has two compliant contact elements as pin element and the sliding contact elements of a central conductor are located more centrally along the longitudinal length of the probe and as with the embodiment of FIGS. 10A - 10D the probe is provided with a pair of compressible springs with one located below and the other above the central conductor and inside the shield.
• FIGS. 12A - 12D provide various views of a pseudo coaxial probe that includes a relatively incompressible central conductor that can elastically bend or buckle which is located within a cage-like outer shielding conductor, and is spaced from the outer conductor by dielectric elements that are attached to the central or to the outer conductor where the outer conductor includes features that allow compliance along one axis that is substantially perpendicular to a local longitudinal axis of the probe but not along the other axis which is locally perpendicular to both.
• a relatively incompressible central conductor that can elastically bend or buckle which is located within a cage-like outer shielding conductor, and is spaced from the outer conductor by dielectric elements that are attached to the central or to the outer conductor where the outer conductor includes features that allow compliance along one axis that is substantially perpendicular to a local longitudinal axis of the probe but not along the other axis which is locally perpendicular to both.
• FIGS. 1A - 11 illustrate side views of various states in an alternative multi-layer, multi-material electrochemical fabrication process.
• FIGS. 1A - 1G 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 metal form part of the layer.
• FIG. 1 A a side view of a substrate 82 having a surface 88 is shown, onto which patternable photoresist 84 is cast as shown in FIG. 1 B.
• 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.
• a metal 94 e.g., nickel
• FIG. 1 E the photoresist has been removed (i.e. , chemically stripped) from the substrate to expose regions of the substrate 82 which are not covered with the first metal 94.
• 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 over the first metal 94 (which is also conductive).
• FIG. 1G 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.
• FIG. 1 H the result of repeating the process steps shown in FIGS. 1 B - 1G 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. 11 to yield a desired 3-D structure 98 (e.g., component or device).
• a desired 3-D structure 98 e.g., component or device
• FIGS. 1A - 11 Various embodiments of various aspects of the disclosure 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 formed from one or more deposited materials while others are formed from a plurality of build layers, 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.
• microscale structures have lateral features positioned with 0.1 - 10 micron level precision and minimum features size on the order of microns to tens of microns.
• structures with less precise feature placement and/or larger minimum features may be formed.
• higher precision and smaller minimum feature sizes may be desirable.
• 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 0.5 - 50 millimeter range, or somewhat larger, and features positioned with a precision in the micron to 100 micron range and with minimum feature sizes on the order of tens of microns to hundreds of microns.
• various embodiments, alternatives, and techniques disclosed herein may form multi-layer structures using a single patterning technique on all layers or using different patterning techniques on different layers.
• various embodiments of the disclosure 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), and/or 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).
• conformable contact masks and masking operations i.e., operations that use masks which are contacted to but not adhered to a substrate
• 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 prepatterned masking material, and/or (3) direct formation of masks from computer-controlled depositions of material.
• 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.
• the layer-by-layer build up may involve the simultaneous formation of portions of multiple layers.
• 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).
• 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 they cannot be reused), non-sacrificial-type (i.e., not destroyed or excessively damaged, i.e., not damaged to the extent 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.
• references numbers are included in many of the figures wherein like numbers are used to represent similar structures or features in different embodiments.
• the reference numbers are provided in a 3 or 4 digit format which may be followed by letters, dashes, and/or additional numbers, wherein the first digit or first two digits (from the left) represent the figure number while the final digits to the right along with any trailing letters, dashes, or numbers represent a particular general structure or feature.
• two or more figures include a reference having the same right most digits (and following letters, dashes, and additional numbers), it is intended to indicate a similarity of the features indicated.
• FIGS. 2A - 2R provide various views of a sample coaxial pin-probe according to another embodiment wherein the pin probe includes a pin element that is compliantly biased by a rectangular coiled spring to move within a first sheath which is separated from a second surrounding sheath by dielectric spacers.
• a rectangular coaxial pin probe 200 is provided with a pin element 205 including two contact tips 207, 208, also indicated as pin tips or probe tips, connected by an intermediate section being a compliant biasing member 210 that includes, for instance, a coiled, spiraling spring for compliantly biasing each pin tip outward from a guide structure 200G, the guide structure 200G being a rigid guide structure comprising at least an inner conductive sheath 215 and an outer conductive sheath 220.
• the guide structure 200G also includes at least an engagement feature 260, in particular a stop feature on each end of the compliant biasing member 210 that inhibits either end of the compliant biasing member 210 from over extension out of the inner conductive sheath 215.
• the inner conductive sheath 215 has a top surface 215T and bottom surface 215B (but open sides), surrounds the pin element 205 and is in turn surrounded by, spaced from, and electrically isolated from the outer conductive sheath 220 which provides an outer shielding conductor spaced from the combined inner conductive sheath 215 and pin element 205 to provide a coaxial pin probe.
• a dielectric material or dielectric element 230 separates the inner conductive sheath 215 from the outer conductive sheath 220.
• At least one contact tip 207, 208 is a movable contact tip.
• both a first contact tip 207 and a second contact tip 208 of the probe 200 are movable contact tips.
• Spacing and materials may be set to provide a desired impedance for the coaxial probe 200 (e.g., 50 Hz or 75 Hz).
• the movable contact tip 207, 208 can be made of, for example, palladium or rhodium.
• the compliant biasing member 210 may be made of, for example, nickel cobalt or palladium while the inner conductive sheath 215 may be made of or coated with, for example, gold.
• the outer conductive sheath 220 may be formed of, for example, gold, palladium or nickel cobalt.
• the dielectric material or dielectric element 230 may be a plastic or photoresist material (e.g., SU8, parylene, etc.), in particular a deposited material (e.g., spun on, sputtered, sprayed, spread or otherwise deposited). Alternatively, the dielectric material or dielectric element 230 may be a ceramic.
• the inner and outer conductive sheaths 215 and 220 have respective open sides or openings in correspondence of the first contact tip 207 and second contact tip 208, which are free to pass and longitudinally move through such openings, the inner and outer conductive sheaths 215 and 220 having the form of a rectangular pipe or channel.
• the pin element 205 can compress and extend along the longitudinal axis X, while its movement along a transversal axis Y or width and along a build axis Z or height direction is prevented or at least limited by the outer conductive sheath 220.
• a suitably shaped portion of the inner conductive sheath 215 may be provided at the contact tips 207, 208 so as to act as pin sleeves 240 able to guide the contact tips 207, 208 during their movement.
• a pin sleeve 240 may include an upper slide 240U and a lower slide 240L.
• the pin sleeve 240 may include a surface abutting onto an end portion of the compliant biasing member 210 so as to realize the stop feature 260.
• the dielectric material 230 may completely fill the void between the inner and outer conductive sheaths 215, 220, according to a preferred embodiment it is locally positioned at a sufficient number of locations to ensure electrical isolation and position stability while sufficiently limited in usage to allow the vast majority of a space between the inner and outer conductive sheaths 215, 220 to be air filled.
• the ends and central portions of the inner conductive sheath 215 may include an appropriate thickness, width, and length of dielectric material 230 to ensure stable position, as shown in FIG. 2H. In other embodiments, only the ends may include such a dielectric material 230.
• the sides of the outer conductive sheath 220 near the ends and possibly at one or more intermediate locations may also include a dielectric material 230.
• an extension of metal and dielectric material may occupy the space between the inner and outer sheaths 215, 220, forming a standoff, in particular a conductive standoff 250, as shown in FIG. 2E, while in other embodiments only the dielectric material may occupy the space between the inner and outer sheaths 215, 220, forming a sort of dielectric standoff.
• a standoff in particular a conductive standoff 250, as shown in FIG. 2E
• only the dielectric material may occupy the space between the inner and outer sheaths 215, 220, forming a sort of dielectric standoff.
• conductive material is provided between the inner conductive sheath 215 and the outer conductive sheath 220, starting from the inner conductive sheath 215 as a conductive standoff 250, a dielectric material 230 being provided between the conductive standoff 250 and the outer conductive sheath 220 as a dielectric spacer 230T, 230B, in particular two symmetrically disposed dielectric spacers being respectively at the top and at the bottom of the conductive standoff 250.
• the dielectric material 230 may be positioned at an outer surface of the inner conductive sheath 215, at an inner surface of the outer conductive sheath 220 or at an intermediate position with a metal filling in gap.
• the dielectric material 230 and/or the inner and outer sheaths 215, 220 may have reentrant features that help ensure adhesion or locked joining of these elements.
• the dielectric material 230 may only be positioned on one side of the inner and outer sheaths 215, 220 (e.g., only the bottom or only the top) while in other embodiments, the dielectric material 230 may be positioned along opposing sides of the inner and outer sheaths 215, 220 or alternating positions from one side to the other at various positions along the length of the inner and outer sheaths 215, 220 forming respective top spacers 230T and bottom spacers 230B, facing or disposed at different positions along the longitudinal axis X of the probe 200.
• the compliant biasing member 210 is a biasing spring that may take on other configurations (e.g., S-shaped or stair-stepped serpentine, zig-zag, stacked buckled plates with or without spacers, the contact tips may take on other configurations, the length of the probe may vary, as may the thicknesses of walls, spring elements and the like, which can be a portion of the pin element 205 or associated thereto.
• probes may have an overall width and height of any desired amount (e.g., 50 - 400 urns (microns)), a length of any desired amount (e.g., 0.5 mm to 5 mm), a sheath wall thickness of any desired amount which may be different between heights and widths and even vary along the length of the probe (e.g., 5 - 30 urn), gaps of any desired amounts or that may be different in height and width and may vary along the length of the probe (e.g., 5 - 80 urns), spring dimensions that may vary depending on spring type, spring length, parallel or series grouping of spring elements, type of material or coatings, required force, over travel requirements, and the like (e.g., 5 - 50 urns).
• any desired amount e.g., 50 - 400 urns (microns)
• a length of any desired amount e.g., 0.5 mm to 5 mm
• a sheath wall thickness of any desired amount which may be different between
• compliant biasing members 210 and contact tips 207, 208 of the pin element 205 may be formed separately from the inner and outer conductive sheaths 215, 220 and the inner and outer sheaths 215, 220 of the guide structure 200G may be formed separately from one another. According to a preferred embodiment, all probe elements may be formed to together in a single fabrication process to minimize assembly costs.
• contact tips 207, 208 may extend from the inner sheath 215 for formation purposes and to allow a desired level of spring bias (via desired displacement) over an entire working range of displacement of the contact tip 207, 208 due to the compression of the compliant biasing member 210 of the pin element 205.
• multiple inner sheaths may exist within the same outer sheath 220, with or without intermediate dielectric material 230 or isolating outer sheath extensions, located between the inner sheaths.
• one movable contact tip may be replaced by a fixed contact tip.
• the probes may be used in various applications such as wafer test or package test, burn-in or the like, at various pitch spacings (e.g., 75 - 500 microns, e.g., 100 - 200 microns, e.g., 120 - 180 microns).
• pitch spacings e.g. 75 - 500 microns, e.g., 100 - 200 microns, e.g., 120 - 180 microns.
• Other alternatives are also possible and include the features of other embodiments set forth herein and the various alternatives to those other embodiments.
• FIGS. 3A - 30 provide various views of a sample pin probe 300 including a pin element 305 and a guide structure 300G including a sheath 315 that can shunt current from a moveable tip 308 of the pin element 305 to the sheath 315 and then to a fixed tip 307.
• the shunting may occur at or near the movable tip 308 of the pin element 305.
• the probe 300 is provided with the movable tip 308 located at an end of a rectangular spiral compliant biasing member 310 and the fixed tip 307 at the other end of the compliant biasing member 310.
• the movable tip 308 has the shape of a cylindrical, elliptical, or other concave section and may be useful for engaging solder bumps or other nonplanar contacts, such as pillars, of an electronic component, such as a device under test or an interface element to a test circuit such as a space transformer, an interposer or a printed circuit board connected to a testing apparatus (not shown).
• the movable tip 308, or a separate feature of the pin element 305 near the movable tip 308, includes an engagement feature 360, in particular a spring loaded slidable side contact structure or slidable engagement element 360 for contacting an inside surface of the surrounding sheath 315 once the compliant biasing member 310 is compressed from a build length (where opposing features of the compliant biasing member 310 are spaced from one another by gaps that are adequate to ensure that minimum feature size tolerances are met, also indicated as build location gaps) to a working range (where the movable tip 308 can still move with ease while providing axial compliance over an adequate over travel length, and while making electrical contact to form a reliable, radial direction spring bias, and shortened path from the movable tip 308 to the fixed tip 307 where the path includes a substantial length of the sheath 315).
• a build length where opposing features of the compliant biasing member 310 are spaced from one another by gaps that are adequate to ensure that minimum feature size tolerances are met, also indicated as build
• the sheath 315 or other portions of the probe 300 may be made with core material surrounded completely or substantially by shell material (e.g., copper cores surrounded by palladium, gold or nickel cobalt shells) to improve conductivity and current carrying capacity of the probe 300.
• shell material e.g., copper cores surrounded by palladium, gold or nickel cobalt shells
• the slidable engagement element 360 may be part of the movable tip 308 of the pin element 305, and they may contact and be biased against inner side walls of the sheath 315 while in a working range, while in other embodiments they may be in contact with the floor and or ceiling (i.e., the internal lower or upper walls) of the sheath 315.
• the slidable engagement elements 360 may not be part of the movable contact tip 308 of the pin element 305 but instead may be part of the sheath 315 such that they extend inward to contact a portion of the compliant biasing member 310, movable tip 308 or other part of the pin element 305.
• movable tips 307, 308 are provided on each end of the probe 300. In other embodiments, other shapes of the movable tip 308 are possible. In some embodiments, a concave movable tip 308 may be provided with some compliance to allow some degree of tilting if a solder bump or the like is contacted off center.
• the probe dimensions may be similar to those noted in the example of FIGS. 2A - 2P while in others, the probe 300 may be even smaller when no further sheath is used with respect to probe 200.
• a 2 mm probe may be required to handle 200 urn of overtravel.
• some embodiments may require some assembly of probe components, and other embodiments may require movement of pin elements from fabrication or build positions to locations in a working range, some embodiments may require no post layer fabrication assembly at all.
• Other alternatives are also possible and include the features of other embodiments set forth herein and the various alternatives to those other embodiments.
• the sheath 315 may be provided with suitable etching holes 315H, to be used in an etching step during the formation of the probe 300.
• the slidable engagement element 360 comprises a compliant sliding contact 360A able to move in an enlarged region 360E realized at an end portion of the sheath 315 in correspondence of the movable tip 308 by an indent 360I.
• the probe 300 may be provided with a further sheath., in particular an outer sheath, the sheath 315 being an inner sheath which is surrounded by, spaced from, and electrically isolated from the further outer sheath, so forming a coaxial probe, suitable dielectric material, for instance forming a plurality of dielectric spacers, being provided to electrically insulate the inner and outer sheaths.
• a further sheath in particular an outer sheath
• the sheath 315 being an inner sheath which is surrounded by, spaced from, and electrically isolated from the further outer sheath, so forming a coaxial probe, suitable dielectric material, for instance forming a plurality of dielectric spacers, being provided to electrically insulate the inner and outer sheaths.
• FIGS. 4A - 4H provide various views of another sample pin probe 400 having a pin element 405 with a movable tip 408 and a fixed tip 407 wherein the compliant biasing member 410 is a spring positioned between the tips 407, 408 which comprises a plurality of attached or separate but stacked curved or non-planar plates or disks 410A that can be compressed to become more planar while supplying a spring force, the compliant biasing member 410 so compressing along the longitudinal axis X.
• Suitable bridges 410B may couple the disks 410A between one another to form the compliant biasing member 410.
• the bridges 410B may also couple the disks 410A to an inner surface of the sheath 415.
• the probe 400 further comprises engagement feature 460 including engaging stop features 460B, 460T being provided at one end of the compliant biasing member 410 in correspondence of the movable tip 408. More particularly a restricted end portion 460T is formed at the top of the sheath 415, in correspondence of the opening wherethrough the pin element 405 pass, and an enlarged portion 460B positioned at the end of the movable tip 408 facing the compliant biasing member 410 and which abuts against the restricted end portion 460T of the sheath 415 to limit the movement of the movable tip 408 outside the sheath 415.
• engagement feature 460 including engaging stop features 460B, 460T being provided at one end of the compliant biasing member 410 in correspondence of the movable tip 408. More particularly a restricted end portion 460T is formed at the top of the sheath 415, in correspondence of the opening wherethrough the pin element 405 pass, and an enlarged portion 460B positioned at the end of the movable tip 408 facing the comp
• FIGS. 5A - 5I provides another sample pin probe 500 having a pin element 505 with a movable tip 508 and a fixed tip 507 associated to a compliant biasing member 510.
• the compliant biasing member 510 is a spring configuration that includes a fabrication or build position that is different from a working range wherein the movable tip 508 moves from the build position to a use position via movement past an engagement feature 560 which is a sliding contact 560 that allows a feature that moves with the movable tip 508 to slide past it during compression while inhibiting movement back over the feature in the presence of a return force provided by a biasing spring such that the movable contact tip 508 of the pin element 505 remains in the working range and does not return, under normal working conditions, to the fabrication position.
• the sliding contact 560 comprises a spring lock 560T positioned at one end of the movable tip 508 and a retention structure 560B positioned at one end of the interior rigid guide 515, the spring lock 560T moving along a working range and being prevented to move out of the working range by the engagement with the retention structure 560B.
• the probe 500 comprises a guide member 500G including an interior rigid guide 515, the compliant biasing member 510 comprising a top compliant element 510T and a bottom compliant element 510B, being serpentine biasing spring elements at opposite sides of the interior rigid guide 515, which limits the movement of the compliant biasing member 510 along the transversal axis Y perpendicular to the longitudinal axis X of the probe extending from between the tips 507, 508.
• serpentine biasing spring elements of the top and bottom compliant elements 510T, 510B of the present embodiment may be useful to change out the serpentine biasing spring elements of the top and bottom compliant elements 510T, 510B of the present embodiment for a spiral spring or a spring that include elements that attach two axial biasing springs to one another (e.g., via external engaging structures, such as an element extending through a slot in the guide member, or elements that extend around the guide member to help ensure that the moving spring elements do not buckle outward and short against a neighboring probe).
• external engaging structures such as an element extending through a slot in the guide member, or elements that extend around the guide member to help ensure that the moving spring elements do not buckle outward and short against a neighboring probe.
• FIGS. 6A - 6B provide another sample pin probe 600 including a pair of electrically isolated probe elements 600A, 600B that include at least respective movable contact tips 608A, 608B at one end of a pin element 605A, 605B, respectively. Further tips 607A, 607B on the other end of the pin elements 605A, 605B may be fixed tips or movable tips, in the example shown in FIG. 6A being movable tips.
• the movable tips 608A, 608B are rigidly joined one another by a bridge (not shown), for coincident movement but decoupled sufficiently to allow changes in the contact on pads having non-uniformities and wherein the movable tips 608A, 608B are electrically isolated from one another by a dielectric barrier located between the pair or at least spacing members of the pair from each other.
• Probes of this type and variations thereof may be used for fine pitch Kelvin testing of substrates and probe packages. Probes of this embodiment may have similar sizes and pitches to the example probes of FIGS. 2A - 5H. Numerous other alternatives to the present embodiment exist and may include the features of other embodiments set forth herein and the various alternatives to those other embodiments.
• the probe 600 includes a guide structure 600G comprising respective sheaths 615A, 615B, each housing a pin element 605A, 605B, respectively.
• a dielectric material 630 is disposed between the sheaths 615A, 615B so as to electrically insulate the same.
• etching holes 615H may be provided in one or both the sheaths 615A, 615B.
• FIGS. 7A - 7H provide various views of a shielded pseudo coaxial probe 700 according to another embodiment of the disclosure that includes a central conductor as pin element 705 and a guide structure 700G surrounding the central conductor 705. More particularly, the guide structure 700G includes an inner shielding conductor or inner conductive sheath 715 and an outer shielding conductor or outer conductive sheath 720, which has a fixed length.
• the central conductor 705 includes a compliant biasing member 710 in turn including a first and a second biasing elements 710A, 710B, connected to one another at an attachment point 71 OX and surrounded by the inner conductive sheath 715, which is in turn surrounded by, spaced from, and electrically isolated from the outer conductive sheath 720 which provides an outer shielding conductor spaced from the combined inner conductive sheath 715 and pin element 705 to provide a coaxial pin probe.
• a dielectric material or dielectric element 730 separates the inner conductive sheath 715 from the outer conductive sheath 720.
• the dielectric material 730 is locally positioned forming respective top spacers 730T and bottom spacers 730B, facing or disposed at different positions along the longitudinal axis X of the probe 700, at a sufficient number of locations to ensure electrical isolation and position stability while sufficiently limited in usage to allow the vast majority of a space between the inner and outer conductive sheaths 715, 720 to be air filled.
• the dielectric material 730 is provided at the ends and at a central portion of the inner conductive sheath 715, which may also include conductive standoffs 750.
• the first biasing element 710A is connected to a first contacting tip 707 at one end of the central conductor 705 and the second biasing element 710B is connected to a second contacting tip 708 and another end of the central conductor 705, both being movable tips.
• the guide structure 200G also includes at least an engagement feature 760, in particular a stop feature that inhibits either end of the respective biasing element 710A, 710B from over extension out of the inner conductive sheath 715.
• the inner conductive sheath 715 comprises suitable shaped end portions acting as pin sleeves 740 able to guide the respective contact tips 707, 708 during their movement.
• the first and second biasing elements 71 OA, 71 OB are connected at the attachment point 71 OX by a suitable bridge 710XB connecting a top and a bottom conductive standoffs 250 able to set suitable gaps 715G between the inner conductive sheath 715 and the first and second biasing elements 710A, 710B, as shown in FIG. 7H.
• the first and second biasing elements 710A, 710B thus extends at an intermediate location to lower and upper surfaces of the inner conductive sheath 715, and connected to the contact tips 707, 708 on either end that extend through the openings of the inner and outer conductive sheaths 715 and 720, which include stop elements that keep the contact tips from extending too far out of the sheaths via an interaction between stop elements and the shaped side walls when the tips are not contacting surfaces to be electrically connected and the spring elements is not under a compressive load.
• Such variations may include, forgoing the connection of the springs to either of the surfaces in favor of one or more sliding elements that are attached to either side of the spring and that can slide along the edge of the top and/or bottom surfaces to ensure that the spring stays located between the surfaces wherein such catch elements may provide additional periodic conductive paths between the spring and the surfaces for carrying current and improving RF properties of the probe.
• regions of the surfaces and the slides themselves may be formed of a high wear, good electrical contact material (e.g., rhodium) to improve contact/conductive probe performance or to extend wear life of the probes.
• FIGS. 8A - 8C depict a spring 810 comprising a plurality of S-shaped segments that may be used in various embodiments of the disclosure wherein the each S-shaped segment, or at least selected S-Shaped segments, are configured to have widths of varying dimensions, as shown in FIG. 8B, in particular including some narrower regions and some wider regions, that may be designed and formed to optimize performance of the spring such as stress loading as shown in the stress simulation image of FIG. 8C or to optimize other parameters singly or in combinations (e.g., length, spring constant, over travel, stress loading, current carrying capacity, and the like).
• Modifications to the structure of this embodiment are possible and may include, for example, additional spring elements located in parallel or in series, segments taking on configurations other than S-shapes, configurations that vary over the length of the spring, and the like.
• FIGS. 9A - 9E provide various views of a shielded pseudo coaxial probe 900 of another embodiment of the disclosure, similar in some aspects to that of FIGS. 7A - 7H with the notable exception that the pin element 905 is a central conductor 905 surrounded by a single conductive sheath 915 as guide structure 900G and retained at each end by respective retainment structures 970 including rectangular structures with central passages acting as pin sleeves 940 held in position relative to the conductive shield 915 by dielectric spacers 980.
• each retainment structure 970 comprises a first or top dielectric spacer 980 and a second or bottom dielectric spacer 980B, disposed between opposite faces of the rectangular pin sleeve 940 and the conductive sheath 915.
• a mount e.g., a dielectric mount
• the spring forming the compliant biasing member 910 may include one or more non-compressible or non-compliant regions.
• FIGS. 10A - 10D provide another example pseudo coaxial probe 1000 but where only one end has significant compliance.
• the probe 1000 includes a pin element 1005 being a central conductor 1005 having respective contact tips 1007, 1008 and being associated with a compliant biasing member 1010 and surrounded by a conductive sheath 1015 forming a guide structure 1000G of the probe 1000.
• the central conductor 1005 comprises a first portion 1005A over a majority of the length of the probe, which is a substantially incompressible, rigid bar that ends with a movable contact tip 1008 and is attached to the compliant biasing member 1010 which is a compressible spring 1010 by an engagement pin 1090, piercing through the first portion 1005A of the central conductor 1005 to the compressible spring 1010 and comprises a dielectric ring 1090S to electrically insulate the two elements.
• the compressible spring 1010 is connected to the conductive sheath 1015 at attachment points 1010Y.
• the probe 1000 comprises a retainment structure 1070 having a rectangular pin sleeve 1040 housing the first portion 1005A of the central conductor 1005 and being connected to the conductive sheath 1015 via a dielectric spacer 1080.
• the central conductor 1005 further comprises a second portion 1005B at an opposite end with respect to the first portion 1005A which slidably engages the second portion 1005B at a sliding contact or mount 1075, in turn connected to the re conductive sheath 1015 by respective dielectric spacers 1075T, 1075B.
• the second portion 1005B of the central conductor 1005 is a substantially fixed contact element, which is held and electrically isolated from the conductive sheath 1015 by a fixed contact 1085 that include respective dielectric spacers 1085T, 1085B.
• the first portion 1005A of the central conductor 1005 can slide against the sliding contact or mount 1075 as the spring forming the compliant biasing member 1010 compresses, while the second portion 1005B of the central conductor 1005 which ends with a further contact tip 1007 is attached to the conductive sheath 1015 and is left unmoved, the further contact tip 1070 being thus a fixed tip.
• the sliding contact mechanism allows controllable contact and movement of the bar forming the first portion 1005A of the central conductor 1005 under compressive force or under restorative spring force.
• the compressible spring 1010 may be fixed to the central conductor 1005 without a dielectric ring, and a dielectric may be used to isolate an opposite end of the compressible spring 1010 from the conductive shield 1015.
• the compressible spring 1010 may be formed with dielectric elements that inhibit contact to surfaces too which shorting is to be avoided.
• FIGS. 11 A - 111 provide various views of an embodiment similar to that of FIGS. 10A - 10D with the primary exception being that the probe 1100 has a pin element 1105 including a central conductive bar 1105 formed by two sliding contact elements 1105A, 1105B, each having a respective contact tip 1107, 1108, and a compliant biasing member 1110 formed by two compliant contact elements 1110A, 1110B associated to the central conductive bar 1105 along the longitudinal axis X of the probe 1100.
• the two compliant contact elements 1110A, 1110B are compressible springs with one located below and the other above the central conductor bar 1105.
• the probe 1100 also includes a guide structure 1000G being a conductive shield 1115 surrounding the central conductor bar 1105 and the two compliant contact elements 1110A, 1110B. Moreover, near the movable contact tips 1107, 1108, the probe 1100 comprises respective retainment structures 1070, each having a rectangular pin sleeve 1140 housing one of the two sliding contact elements 1105A, 1105B of the central conductor 11005 and being connected to the conductive sheath 1115 via a dielectric spacer 1180.
• the two sliding contact elements 1105A, 1105B of the central conductor 1105 are connected one another at two sliding contacts or mounts 1175A, 1175B, in turn connected to the conductive sheath 1115 by respective dielectric spacers.
• the two compliant contact elements 1110A, 1110B are connected to the central conductor 1105 by respective engagement pins 1190A, 1190B, piercing through the sliding contact elements 1105A, 1105B of the central conductor 1105 to the respective two compliant contact elements 1110A, 1110B.
• the engagement pins 1190A, 1190B may comprise dielectric rings to electrically insulate the two elements.
• the sliding contact elements 1105A, 1105B of the central conductor 1105 are connected at a sliding portion 1105XS, being comprised between the two sliding contacts 1175A, 1175B, wherein the first contact element 1105A slides against the second contact element 1105B.
• the second contact element 1105B has a bar portion 1105BXS sliding within a U- shaped portion 1105AXS of the first contact element 1105A.
• numerous variations are possible and include moving the springs to the outside of the shielding conductor or sheath via radially extending arms that connect the springs to a point on the central conductor(s) via a dielectric interface and connect the opposite end of the spring to the shielding conductor where the radially extending arms may be located in a slot in the shielding conductor of adequate length and position to allow the contact end, or ends, of the probe to undergo required overtravel when making contact to electrical components.
• FIGS. 12A - 12D provide various views of a pseudo coaxial probe 1200 that includes a pin element 1205 being a central conductor 1205 which is relatively incompressible but can elastically bend or buckle, and is located within a guide structure 1200G being a cage-like shielding conductor or sheath 1215, the central conductor 1205 being spaced from the conductive sheath 1215 by a plurality of sliding contacts 1275, being made of a dielectric material 1230 and disposed along the length of the central conductor 1205 as well as retainment structures 1270 at the ends of the central conductor 1205.
• the conductive sheath 1215 comprises a plurality of compliant guide portions 1215CP, inserted between pairs of sliding contacts 1275 and being able to elastically bend or buckle following the deformation, in particular the bending of the central conductor 1205.
• the compliant guide portions 1215CP are substantially coil-shaped and comprise enlarged holes as stress relief features 1215SR, as shown in FIG. 12C.
• the probe 1200 includes features that allow compliance along one axis, for the transversal axis Y or width, that is substantially perpendicular to the longitudinal axis X of the probe but not along the other axis, for instance the build axis Z or height, which is locally perpendicular to both.
• the central conductor also including features that preferentially enable compliance along a first axis and inhibit compliance along another axis that is perpendicular to the first axis and to the longitudinal axis X of the probe.
• sheathed pin probe structures may provide a compliant tip at only one end of a sheath while electrical contact to a non-compliant end may be made by solder bonding, wire bonding, diffusion bonding, ultrasonic welding, brazing, or the like. Alternatively bonding to the noncompliant end may simply occur as a result of pressure from mating the compliant end to a contact location.
• the structure may be formed with regions of a wear resistant and/or good electrical contact material (e.g., rhodium) to improve reliability of electrical contact and/or wear life of the probe.
• the contact region in any given sliding location, from a single layer that includes protrusions on each side of the contact region, relative to the layers above and below to ensure that any layer-to-layer positions variations (e.g., due to offset tolerances) do not impact performance.
• Still other embodiments may be created by combining the various embodiments and their alternatives which have been set forth herein with other embodiments and their alternatives which have been set forth herein.
• some 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), beryllium copper (BeCu), nickel phosphorous (Ni-P), tungsten (W), aluminum copper (Al-Cu), steel, P7 alloy, palladium, 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.
• Structural or sacrificial dielectric materials may be incorporated into embodiments of the present disclosure in a variety of different ways. Such materials may form a third material or higher deposited on selected layers or may form one of the first two materials deposited on some layers. Some embodiments may employ diffusion bonding or the like to enhance adhesion between successive layers of material.
• Some 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, nickel-phosphorous, nickel-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.
• headers are intended to limit the application of teachings found in one portion of the specification from applying to other portions of the specification.
• 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 application functional and do not otherwise contradict or remove all benefits of the adopted embodiment.
• Various other embodiments of the present disclosure exist.

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• 2023
  • 2023-08-15 WO PCT/US2023/030258 patent/WO2024215351A1/en unknown
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