TEST SOCKET AND PROBE WITH STEPPED COLLAR FOR SEMICONDUCTOR INTEGRATED CIRCUITS
20240377433 ยท 2024-11-14
Inventors
Cpc classification
G01R1/0483
PHYSICS
G01R3/00
PHYSICS
International classification
Abstract
A contact probe includes a shell having a first end and an opposed second end. The shell defines an interior chamber therein and a longitudinal axis extending through the first end and the second end. The contact probe further includes a plunger partially received within the interior chamber and extending longitudinally outward of the first end. The plunger includes a tip for electrically connecting the contact probe to an external chip. The contact probe further includes a stepped collar coupled to the shell. The stepped collar includes a first step and a second step. The second step extends about the shell and the first step extends around the plunger longitudinally between the second step and the tip.
Claims
1. A contact probe comprising: a shell comprising a first end and an opposed second end, said shell defining an interior chamber therein and a longitudinal axis extending through said first end and said second end; a plunger partially received within the interior chamber and extending longitudinally outward of said first end, said plunger comprising a tip for electrically connecting said contact probe to an external chip; and a stepped collar coupled to said shell, said stepped collar comprising a first step and a second step, said second step extending about said shell and said first step extending around said plunger longitudinally between said second step and said tip.
2. The contact probe of claim 1, wherein said first step has a first diameter perpendicular to the longitudinal axis and said second step has a second diameter perpendicular to the longitudinal axis, and wherein the first diameter is less than the second diameter.
3. The contact probe of claim 1, wherein said stepped collar further includes a first axial end on said first step and a second, opposed axial end on said second step, said first step comprising an outer surface extending longitudinally from said first axial end to said second step.
4. The contact probe of claim 3, wherein said first axial end defines a first opening and said second axial end defines a second opening, and wherein said plunger extends through the first opening and said shell extends through the second opening.
5. The contact probe of claim 3, wherein said stepped collar comprises a first interior surface and a second interior surface, said first interior surface extending longitudinally from said first axial end to said second interior surface, said second interior surface extending longitudinally from said first interior surface to said second axial end, and wherein said first interior surface and said second interior surface cooperatively define a slot sized to receive the plunger therein.
6. The contact probe of claim 5, wherein said plunger comprises a neck extending outward of said shell to said tip, and wherein said first interior surface contacts said neck.
7. The contact probe of claim 5, wherein said second interior surface extends circumferentially about said shell radially outward of said first interior surface.
8. The contact probe of claim 1, wherein said stepped collar defines a longitudinally extending slot, and wherein said shell comprises an outer surface received within said slot and a ledge extending radially outward of said outer surface, said ledge being positioned on said shell to contact said first step.
9. The contact probe of claim 1, wherein said plunger further comprises: a base portion received within the interior chamber; a shoulder positioned to contact said first end of said shell; a crown comprising said tip; and a neck extending from said shoulder to said crown.
10. The contact probe of claim 9, wherein said stepped collar further comprises an interior surface that engages said neck, and wherein said crown extends radially outward of said neck.
11. The contact probe of claim 1, wherein said plunger is a first plunger and said tip is a first tip, and wherein said contact probe further comprises: a second plunger at least partially received within the interior chamber and extending longitudinally outward of said second end, said second plunger comprising a second tip for electrically connecting said contact probe to a conductive pad; and a biasing element connecting said first plunger to said second plunger.
12. The contact probe of claim 1, wherein said stepped collar is a first collar, and wherein said contact probe further comprises a second collar coupled to said shell longitudinally between said second end and said stepped collar.
13. The contact probe of claim 1, wherein said stepped collar is formed of an insulative material.
14. An electrical connector assembly comprising: a socket body comprising a neck and a central portion extending within said socket body and cooperatively defining a cavity therein; and a contact probe at least partially positioned within the cavity, said contact probe comprising: a shell comprising a first end and an opposed second end, said shell defining an interior chamber therein and a longitudinal axis extending through said first end and said second end; a plunger partially received within the interior chamber and extending longitudinally outward of said first end, said plunger comprising a tip for electrically connecting said contact probe to an external chip; and a stepped collar coupled to said shell, said stepped collar comprising a first step sized in correspondence with said neck and a second step sized in correspondence with said central portion.
15. The electrical connector assembly of claim 14, wherein said first step has a first diameter perpendicular to the longitudinal axis and said second step has a second diameter perpendicular to the longitudinal axis, and wherein the first diameter is less than the second diameter.
16. The electrical connector assembly of claim 14, wherein said stepped collar further includes a first axial end on said first step and a second, opposed axial end on said second step, said first step comprising an outer surface extending longitudinally from said first axial end to said second step.
17. The electrical connector assembly of claim 16, wherein said first axial end defines a first opening and said second axial end defines a second opening, and wherein said plunger extends through the first opening and said shell extends through the second opening.
18. The electrical connector assembly of claim 16, wherein said stepped collar comprises a first interior surface and a second interior surface, said first interior surface extending longitudinally from said first axial end to said second interior surface, said second interior surface extending longitudinally from said first interior surface to said second axial end, and wherein said first interior surface and said second interior surface cooperatively define a slot sized to receive the plunger therein.
19. The electrical connector assembly of claim 18, wherein said plunger comprises a neck extending outward of said shell to said tip, and wherein said first interior surface contacts said neck.
20. A method of forming a contact probe comprising: providing a shell including a first end and an opposed second end, the shell defining an interior chamber therein and a longitudinal axis extending through the first end and the second end; positioning a plunger at least partially within the interior chamber, the plunger extending longitudinally outward of the first end to a tip for electrically connecting the contact probe to an external chip; and coupling a stepped collar to the shell, the stepped collar including a first step and a second step, the second step extending about the shell and the first step extending around the plunger longitudinally between the second step and the tip.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0007]
[0008]
[0009]
[0010]
[0011]
[0012]
DETAILED DESCRIPTION
[0013] Embodiments of the disclosed test socket provide a spring probe having a stepped retaining collar. The disclosed test sockets are configured to receive a flat no-leads IC package, such as a QFN IC and include probes that provide electrical connection between the IC and a load board, such as a PCB. To engage the load board with an IC under test, the IC is lowered onto the test socket making connections with spring probes extending between the IC and the load board. The spring probes each include contact plungers the IC is lowered onto for testing. A stepped collar surrounds at least a portion of the plungers to align the plungers in position for connection with the IC and limit lateral displacement of the plungers that may result over repeated cycles. The test sockets described herein further allow for spacing the spring probe from the test socket during use, generally reducing wear on the spring probe resulting from contact with the test socket, and improving signal performance.
[0014]
[0015]
[0016] In the example embodiment, each of the illustrated spring probes 114 and cavities 116 are substantially identical. A third cavity 116 is shown in
[0017] Referring to
[0018] In the example embodiment, socket retainer 110 is coupled to socket body 106 such that the cavities 108, 112 (
[0019] In the example embodiment, spring probes 114 are each received within cavities 116 and include a first plunger 138, a second plunger 140, a shell 142, a stepped collar 144 (broadly referred to herein as a first collar), and an body collar 146 (broadly referred to herein as a second collar). Longitudinal axis L.sub.1 extends through first plunger 138 and second plunger 140. Shell 142 is tubular (e.g., cylindrical or having a cross-section with a shape, such as a circular, oval, square, rectangular, or other shape). At least a portion of first and second plungers 138, 140 are disposed within shell 142, as described in greater detail below.
[0020] First plunger 138 includes a crown 152 that extends outwardly from the shell 142. Crown 152 is configured to contact and electrically connect to conductive pads 104 of IC chip 102. First plunger 138 is attached to the shell 142 so that first plunger 138 and the shell 142 move together. For example, first plunger 138 includes a first base portion 156 (
[0021] In the example embodiment, spring probe 114 includes stepped collar 144 coupled to shell 142 proximate first plunger 138 and body collar 146 coupled to shell 142 proximate second plunger 140. Stepped collar 144 and body collar 146 are each made of an insulative material having a low dielectric constant, such as polytetrafluoroethylene (PTFE) or other nonconductive material, such as plastic, polymer, rubber, etc. Stepped collar 144 is shaped as a stepped cylinder and includes a first step 148 and a second step 150. In other embodiments, stepped collar 144 may have any suitable shape (e.g., oval, square, rectangular, etc.)
[0022] As shown in
[0023] Body collar 146 is fitted on shell 142 to surround a portion of shell 142. Body collar 146 is sized in correspondence with central portion 132 of cavity 116. Body collar 146 has a diameter D.sub.3 that is approximately equal to, or slightly less than, the diameter C.sub.3 of central portion 132. As a result, stepped collar 144 and body collar 146 align spring probe within cavities 116 such that spring probe 114, or more specifically, conductive elements of spring probe 114, such as shell 142, first plunger 138, and second plunger 140, are spaced from and do not directly contact walls of cavities 116. As a result, in some embodiments, cavities 116 may not include an insulation coating.
[0024] Referring to
[0025]
[0026] Referring to
[0027] In the example embodiment, crown 152 includes a plurality of first contact tips 166 (e.g., four in embodiment of
[0028] Referring to
[0029] As shown in
[0030]
[0031] As shown in
[0032] In the example embodiment, second axial end 188 of stepped collar 144 defines a second opening 202 connected to first opening 186 at first axial end 184 by a slot 204 extending longitudinally through stepped collar 144. Shell 142 extends through second opening 202 and is in fitted contact with stepped collar 144. In particular, stepped collar 144 includes a first interior surface 206 and a second interior surface 208 that cooperatively define slot 204. First interior surface 206 extends longitudinally from first axial end 184 to second interior surface 208. Second interior surface 208 extends longitudinally from first interior surface 206 to second axial end 188. First interior surface 206 extends circumferentially about neck 168 and is in fitted contact with neck 168 of first plunger 138 to restrain lateral movement of first plunger 138 during use. At least a portion of second interior surface 208 extends circumferentially about shell 142 and is in fitted contact with shell 142. In particular, in the example embodiment, second interior surface 208 extends longitudinally outward of shell 142 and shoulder 170 (i.e., to the right of the page in
[0033] As shown in
[0034] To assemble spring probe 114, first plunger 138, biasing element 194, and second plunger 140 may be separately connected and formed into a single assembly prior to insertion into cavity 192 of shell 142. Tip portion 154 of second plunger 140 may be inserted into cavity 192 at first end 172 and biasing element 194 and first plunger 138 may be fed with second plunger 140 into cavity 192 until second plunger 140 extends outward of opening 200 at second end 174. Stepped collar 144 is then slid over first plunger 138 (e.g., by flexing first axial end 184 to permit passage of crown 152 through first opening 186) and is secured in position between crown 152 and first ledge 178. Body collar 146 is slid over second plunger 140 and onto shell 142 between second ledge 180 and third ledge 182 in substantially the same manner as stepped collar 144. In some embodiments, collars 144, 146 are secured to shell 142 (e.g., by an adhesive). In other embodiments, spring probe 114 is assembled by any suitable process that enables spring probe 114 to function as described herein.
[0035] The technical effects of the systems and apparatuses described herein may include: (a) aligning the contact plunger in position within the test socket for contact with the IC chip; (b) reducing wear on the contact plunger resulting from lateral displacement of the contact plunger when setting the IC into the test socket; (c) reducing contact electrical resistance between test socket and spring probe by securing spring probe in the socket with the collars; and (d) improving signal quality between the IC and a PCB by insulating the spring probe from the test socket.
[0036] In the foregoing specification and the claims that follow, a number of terms are referenced that have the following meanings.
[0037] As used herein, an element or step recited in the singular and preceded with the word a or an should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to example implementation or one implementation of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features.
[0038] Optional or optionally means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
[0039] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as about, approximately. and substantially, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here, and throughout the specification and claims, range limitations may be combined or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
[0040] Disjunctive language such as the phrase at least one of X, Y, or Z, unless specifically stated otherwise, is generally understood within the context as used to state that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present. Additionally, conjunctive language such as the phrase at least one of X, Y, and Z, unless specifically stated otherwise, should also be understood to mean X, Y, Z, or any combination thereof, including X, Y, and/or Z.
[0041] The systems and methods described herein are not limited to the specific embodiments described herein, but rather, components of the systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein.
[0042] Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
[0043] This written description uses examples to provide details on the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.