REVERSIBLE ATTACHMENT MICRO CONNECTOR

A reversible attachment micro connector includes a pin and mounted on a first assembly and a socket mounted on a second assembly. The socket is operational to mate with the pin at least two times to establish an electrical connection, and separate from the pin at least once. The socket includes a surround structure that defines a cavity with a floor. The cavity is sized to receive the pin. Multiple tabs are disposed in the cavity and coupled to the surround structure. The tabs have a negative longitudinal curvature that protrudes into the cavity. The tabs bend in three dimensions during insertion of the pin and removal of the pin. The negative longitudinal curvature generates a stress distribution that is uniform between the pin and the tabs while the pin is seated in the socket. The pin is retained in the socket based on the stress distribution.

TECHNICAL FIELD

The disclosure relates generally to flip-chip connections, and in particular, to micro connectors.

BACKGROUND

Next-generation computing cores employ fine pitch, three-dimensional integration of multiple integrated circuits fabricated in different process technologies (i.e., deep submicron CMOS logic, dense memory, high performance electrical and/or optical input/output circuitry, power delivery, and novel computational processing layers, such as neuromorphic processing). Successful development of such systems involves techniques to test and identify known good die with fine-pitch pads, as well as techniques for reworking assemblies with the die. Existing rework techniques utilizing strain-based micro connectors exhibit nonuniform stress distributions that work against temporary connections.

Accordingly, those skilled in the art continue with research and development efforts in the field of micro connectors with uniform stress distributions that maintain a pin inserted in a socket without degrading the socket.

SUMMARY

A reversible attachment micro connector is provided herein. The reversible attachment micro connector includes a pin mounted on a first assembly and a socket mounted on a second assembly. The socket is operational to mate with the pin at least two times to establish an electrical connection. The socket is further operational to separate from the pin at least once. The socket includes a surround structure that defines a cavity with a floor. The cavity is sized to receive the pin. A plurality of tabs are disposed in the cavity and coupled to the surround structure. The plurality of tabs have a negative longitudinal curvature that protrudes into the cavity. The plurality of tabs bend in three dimensions during insertion of the pin and removal of the pin. The negative longitudinal curvature generates a stress distribution that is uniform between the pin and the plurality of tabs while the pin is seated in the socket. The pin is retained in the socket based on the stress distribution.

In one or more embodiments, the reversible attachment micro connector includes a plurality of contact layers coupled to the plurality of tabs, made of metal, and operational to engage the pin.

In one or more embodiments of the reversible attachment micro connector, the plurality of contact layers bend asymmetrically in a transverse direction through buckling instabilities during the insertion and the removal of the pin.

In one or more embodiments of the reversible attachment micro connector, the stress distribution is within an elastic regime of the metal that forms the plurality of contact layers.

In one or more embodiments of the reversible attachment micro connector, the plurality of contact layers is discontinuous around the cavity.

In one or more embodiments of the reversible attachment micro connector, the plurality of contact layers is perpendicular to the floor of the cavity.

In one or more embodiments of the reversible attachment micro connector, the surround structure and the plurality of tabs are formed of an elastomer.

In one or more embodiments of the reversible attachment micro connector, the elastomer provides a spring force that biases the plurality of contact layers against the pin.

In one or more embodiments, the reversible attachment micro connector includes a pad mounted on the floor of the socket, and operational to form a thermal compression bond with the pin.

In one or more embodiments of the reversible attachment micro connector, the pin has a tapered wall operational to engage the plurality of tabs.

In one or more embodiments of the reversible attachment micro connector, the pin has a cylindrical wall operational to engage the plurality of tabs.

In one or more embodiments of the reversible attachment micro connector, the first assembly includes a first array of pins. The second assembly includes a second array of sockets.

A method for reversible attachment connection is provided herein. The method includes inserting a pin into a socket a first time to establish an electrical connection that mates a first assembly with a second assembly. The pin is mounted on the first assembly. The socket is mounted on the second assembly. The socket includes a surround structure that defines a cavity with a floor. A plurality of tabs is disposed in the cavity and coupled to the surround structure. The plurality of tabs have a negative longitudinal curvature that protrudes into the cavity. The method includes bending the plurality of tabs in three dimensions during the inserting of the pin the first time, generating a stress distribution with the negative longitudinal curvature that is uniform between the pin and the plurality of tabs while the pin is seated in the socket, retaining the pin in the socket based on the stress distribution, removing the pin from the socket to separate the first assembly from the second assembly, bending the plurality of tabs in the three dimensions during the removing of the pin, and inserting the pin into the socket a second time to reestablish the electrical connection.

In one or more embodiments, the method further includes engaging the pin with a plurality of contact layers coupled to the plurality of tabs, wherein the plurality of contact layers are made of metal.

In one or more embodiments, the method further includes bending the plurality of contact layers asymmetrically in a transverse direction through buckling instabilities during the inserting of the pin the first time and the removing of the pin.

In one or more embodiments, the method further includes biasing a plurality of contact layers against the pin with a spring force provided by an elastomer that forms the plurality of tabs, wherein the plurality of contact layers are coupled to the plurality of tabs, made of metal, and operational to engage the pin.

In one or more embodiments, the method further includes forming a thermal compression bond between a pad mounted on the floor of the socket and the pin.

A reversible attachment micro connector is provided herein. The reversible attachment micro connector includes a first array of pins mounted on a first assembly and a second array of sockets mounted on a second assembly. The second array of sockets is operational to mate with the first array of pins at least two times to establish an electrical connection. The second array of sockets is further operational to separate from the first array of pins at least once. Individual sockets in the second array of sockets include a surround structure that defines a cavity with a floor. The cavity is sized to receive an individual pin of the first array of pins. A plurality of tabs are disposed in the cavity and coupled to the surround structure. The plurality of tabs have a negative longitudinal curvature that protrudes into the cavity. The plurality of tabs bend in three dimensions during insertion of the individual pin and removal of the individual pin. The negative longitudinal curvature generates a stress distribution that is uniform between the individual pin and the plurality of tabs while the individual pin is seated in the socket. The individual pin is retained in the individual socket based on the stress distribution.

In one or more embodiments of the reversible attachment micro connector, a pitch of the second array of sockets is at most approximately 10 micrometers.

In one or more embodiments of the reversible attachment micro connector, a misalignment between the first assembly and the second assembly while mated is at most approximately 0.1 micrometers.

DETAILED DESCRIPTION

Embodiments of the present disclosure include an apparatus and/or a method that provides reversible attachment micro connectors. The reversible attachment capability generally allows probing and/or temporary assembly of multi-dimensional, fine pitch microelectronic assemblies through multiple reversible connect/disconnect cycles (e.g., at least two times) without external clamps. In various embodiments, the fine pitch among the micro connectors may be less than several microns (e.g., ≤10 μm). Each micro connector is configured as a pin and a socket (or receptacle). Mating surfaces of the socket have protruding tabs with negative longitudinal curvature. A function of an array of the micro connectors is to temporarily attach two-and-a-half dimensional and three-dimensional stack microelectronic assemblies for testing and screening. The micro connector arrays may also provide permanent integration of the assemblies using thermocompression bonding.

Each socket of the micro connector provides a clamping mechanism to a corresponding pin. The clamping mechanism utilizes a three-dimensional bending of protruding tab sidewalls during interaction (e.g., insertion and seating) with the pin that controls mechanical properties of the socket. In particular, a stiffness of the negatively curved protruding tab contact layers (e.g., in a longitudinal, depth direction) is a design parameter that tailors stress distributions between the mating pins (e.g., tapered and straight walled) and the socket. Elastic strain energy generated during the mating process is resolved by the transverse bending (through buckling instabilities) of the sidewalls rather than through strain, as is done in conventional designs. The bucking behavior may be controlled by employing different sidewall constraints. Engineering the mechanical properties of the sockets through various constraints (e.g., fixed vs. free edges), dimensions of the metal contacting surfaces, and elastomer surrounds offer possibilities of designs with uniform stress distributions for mating with either tapered pins or straight-walled pins. Eliminating the stress concentrations during mating and seating is beneficial for the reversibility function, and for retaining tapered pins in an initially straight-wall receptacle. The mechanics of this receptacle is unlike alternative fine-pitch collar designs that primarily resolve elastic energy through in-plane strains resulting in high stress concentrations at the top of the receptacle well leading to forces that tend to expel the pin or cold weld parts together.

Referring toFIG.1, a schematic diagram of an example implementation of a compression system100is shown in accordance with one or more exemplary embodiments. The compression system100generally includes a press102and a computer120. The press102includes a top chuck104, a bottom chuck106, a load cell108, and a heater110. The computer120includes one or more processors122(one shown) and one or more memory devices124(one shown).

The press102implements a precision die bonder. In various embodiments, the press102implements an assembly-to-assembly alignment and thermocompression press. The press102is operational to align and press two assemblies together to form inter-assembly connections. The alignment may be provided by movement of the top chuck104relative to the bottom chuck106in multiple dimensions. By way of example, the top chuck104may tilt130relative to the bottom chuck106. The tilt130may include movement in a pitch direction130aand a roll direction130b. In some embodiments, the bottom chuck106may be rotatable relative to the top chuck104in a yaw direction132. In other embodiments, the top chuck104may be rotatable relative to the bottom chuck106in the yaw direction132. The top chuck104is also moveable relative to the bottom chuck106in a vertical direction134.

Movement of the top chuck104downward along the vertical direction134presses a first assembly140being held by the bottom chuck106against a second assembly160being held by the top chuck104with an applied pressure136(or force). The applied pressure136engages pin-and-socket micro connectors. The pressure136may be reversed to disengage the micro connectors. In some embodiments, the first assembly140may be held by the top chuck104and the second assembly160may be held by the bottom chuck106. The load cell108measures the applied pressure136being applied between the first assembly140and the second assembly160.

The top chuck104and the bottom chuck106each implement a vacuum chuck. The top chuck104and the bottom chuck106are operational to hold the second assembly160and the first assembly140during alignment, mating, disconnecting, and bonding.

The load cell108implements a pressure sensor. The load cell108is operational to detect the applied pressure136applied by the second assembly160onto the first assembly140during a calibration test of the press102.

The heater110implements a variable heat source controlled by the computer120. The heater110is operational to heat the first assembly140and the second assembly160to one or more temperatures determined by the computer120. During a thermocompression bonding process, the heater110raises the temperature of the first assembly140and the second assembly160to a bonding temperature appropriate for bonding the materials used in inter-assembly bump bonds.

The computer120is coupled to the heater110and the load cell108. The computer120implements one or more data processing computers. In embodiments with multiple computers120, the individual computers120are coupled together to share data, memory space, and processing resources. The computer120may be operational to store the configuration data of the press102and execute software used to control the heater110and analyze the information received from the load cell108.

The processor122implements one or more processors within the computer120. The processor122is in communication with the memory device124to exchange commands and data. The processor122is operational to execute the software tools used to analyze the data generated by the load cell108.

The memory device124implements one or more non-transitory computer readable storage devices (e.g., random access memory, read-only memory, magnetic hard drives, solid-state drives, etc.). The memory device124stores software programs (or tools) that are executed by the processor122.

The thermocompression bonding process applied to the inter-assembly bond structures may be similar to conventional bump bond structure bonding processes. For example, thermocompression bonding may be performed at approximately 200 degrees Celsius (° C.) for gold and approximately 300° C. for copper and aluminum while under pressure (e.g., >40 megapascals (MPa) of bond metal area).

The first assembly140and the second assembly160implement substrates. In various embodiments, the substrates may be semiconductor substrates. The semiconductors generally includes silicon, germanium, gallium arsenide, aluminum gallium arsenide, silicon carbide, gallium nitride, indium phosphide and the like. The substrates may be in the form of a semiconductor die, a semiconductor tile, or a semiconductor wafer. The substrates may be formed of other materials to meet the design criteria of a particular application.

Referring toFIG.2, a schematic perspective diagram of an example design of a reversible attachment micro connector200is shown in accordance with one or more exemplary embodiments. The reversible attachment micro connector200is dimensionally scalable for reversible fine-pitch attachment applications. The reversible attachment micro connector200generally includes a pin202and a socket204. While mated, the pin202and the socket204form an electrical connection205.

The pins202implements a thermocompression pin. A height of the pin202may range from approximately 3 μm to approximately 5 μm. A diameter of the pin202may range from approximately 2 μm to approximately 3 μm. The pin202illustrated over the socket204is an example as a tapered pin202a. Another pin202illustrated to a side of the socket204is an example of a straight pin202b.

Theoretical and experimental work that treats the stiffening of thin sheets of paper, subjected to two-dimensional bending, provides a mathematical framework for understanding the clamping mechanism employed in the socket204with thin metal contact layers. See for example, “How two-dimensional bending can extraordinarily stiffen thin sheets”, V. Pini et al., Scientific Reports, 6, 29627, 2016, which is hereby incorporated by reference in its entirety. Equations for various constraint states are provided therein and provide guidance for tailoring the construction of a socket204using the complex bending mechanisms to generate uniform stress distributions for a tapered and straight-walled pin profiles. Subsequently, several general tenants may be stated that provide the working principles for the mechanics of the thin wall socket204. The tenants generally include:

1. The stiffness of the unconstrained socket sidewall surface (e.g., contact layers) increases with the longitudinal curvature. The stiffness of the sidewalls, controlled by shape and dimensions in a free unconstrained state, governs the insertion and retention forces for mating with the pin202.

2. Bending asymmetry: the inward and outward bending stiffness of the sidewalls of the tabs are different due to the longitudinal curvature. The stiffness of the negative curvature sidewalls is smaller in the outward direction compared to the inward direction.

3. In-plane stresses are developed when the sidewalls are subject to biaxial bending. The biaxial bending is a result of the high energy cost of in-plane straining ˜(h/L) in comparison to the bending energy ˜(h/L)3, where h is the thickness and L is the length of the sidewalls. A manifestation of the effect is that small in-plane stresses in the sidewalls give rise to formation of three-dimensional configurations (e.g., buckling instabilities).

4. Three-dimensional configurations developed due to inserting a pin202into a cavity of the socket204gives rise to internal strain configurations within the sidewalls. The curvature induced in-plane strain increases the elastic energy of the contact layer, leading to large stiffening. A resulting biaxial bending transition point is pushed lower in the socket204(e.g., closer to a constrained edge) leading to uniform stress distributions for a tapered pin202ainsertion.

Based on such principles and experimentation (e.g., from bending paper and other thin sheets), the negative transverse curvature of the protruding tabs of a socket204generate uniform stress distributions for a given mating pin profile (e.g., tapered pin202aor straight pin202b) by modifying how the sidewalls that forms the tabs are constrained and the design (e.g., width and thickness) of the contact layers. For example, if a bottom edge of the tabs are fixed, a varying stiffness is generated for longitudinally bending the sidewalls that increases from the top to the bottom of the socket204due to the constraint. The varying stiffness produces a near uniform stress distributions (e.g., pressure) during the mating with a tapered pin202a. Other design parameters that affect the mechanical properties of the receptacle include, but are not limited to, a width (e.g., uniform or variable) of the contact layers (e.g., slender contact layers only have one degree of bending) and the thickness of the contact layers.

Referring toFIG.3, a schematic perspective diagram of an example design of a socket204is shown in accordance with one or more exemplary embodiments. The socket204includes a surround structure206that defines a cavity208with a floor209. Multiple tabs210a-210d(four shown) with contact layers212a-212dprotrude into the cavity208.

The surround structure206may be a polyimide layer that surrounds (either a continuous field or separated islands) a respective cavity208to provide restoring and clamping force for the contact layers212a-212d. In various embodiments, the surround structure206may be an elastomer. Other materials may be used for the surround structure206to meet the design criteria of a particular application.

The cavity208is sized to receive the pin202. The cavity208is arranged in a basically square pattern with dimensions of 216 micrometers per side. In various embodiments, the dimension216is 10 μm or less (e.g., 6 μm). In various embodiments, a depth218of the cavity208may be approximately 1.5 μm to 3 μm (e.g., 2 μm).

Referring toFIG.4, a graph240of an example stress distribution for the socket204is shown in accordance with one or more exemplary embodiments. The graph240includes an X-axis242and a Y-axis244. The X-axis242illustrates a von Mises stress in units of megaPascals (MPa). The Y-axis244illustrate the depth218of the socket204from bottom to top in units of tenths of a micrometer.

Stress distributions for the design were calculated using finite element analysis (FEA) for a tapered pin202awith a sidewall angle (e.g., 78°) and a socket204. The cavity208had an area dimension (ref. nos.216by216) of 6 μm×6 μm, and a depth218of 2 μm. The overall stress levels from the top to the bottom of the receptacle are uniform and lie within the elastic regime252for gold contacting surfaces of the contact layers212a-212d. The analysis also shows that the average stress level depends on a thickness of contact layers212a-212d. Curves246,248, and250illustrate the stresses for 25 nanometer (nm), 50 nm, and 75 nm thick contact layers212a-212d, respectively.

Referring toFIG.5, a schematic perspective diagram of an example design of another socket204ais shown in accordance with one or more exemplary embodiments. The socket204amay be a variation of the socket204. The socket204aincludes the surround structure206that defines the cavity208. Multiple tabs210a-210d(four shown) with contact layers222a-222dextend into the cavity208.

The contact layers222a-222dmay be perpendicular to the floor209of the cavity208. The contact layers222a-222dmay be narrow, constrained the bottom edge, connected to each other at the top edge by braces224a-224d, and constrained at the sides. The contact layers222a-222dare backed by the surround structure206that provides mechanical support and extra spring force for the contact layers222a-222d. The contact layers222a-222dmay be metal (e.g., gold) contact layers for low resistance connection.

Referring toFIG.6, a graph260of an example stress distribution for the socket204ais shown in accordance with one or more exemplary embodiments. The graph260includes the X-axis242and the Y-axis244. The X-axis242illustrates a von Mises stress in units MPa. The Y-axis244illustrate the depth218of the socket204afrom bottom to top in units of tenths of a micrometer.

Stress distributions for the design were calculated using finite element analysis (FEA) for a tapered pin202awith a sidewall angle (e.g., 78°) and a socket204a. The cavity208had an area dimension (ref. nos.216by216) of 6 μm×6 μm, and a depth218of 2 μm. Curves266,268, and270illustrate the stresses for 25 nm, 50 nm, and 75 nm thick contact layers222a-222d, respectively. Constraining the contact layers222a-222dincreases the average stress levels and results in less uniform stress distributions along the longitudinal direction.

Referring toFIG.7, a schematic cross-section diagram of an example implementation of a socket204bis shown in accordance with one or more exemplary embodiments. The socket204bmay be a variation of the socket204and/or the socket204. The socket204bmay include a pad226disposed on the floor209. In various embodiments, the pad226may be formed of a thermocompression bonding metal. For example, the pad226may be formed of gold228a, copper228b, or aluminum228c. Other metal layers may be implemented to meet the design criteria of a particular application. The socket204bmay have a depth that enables a pin202to contact the pad226. After a final insertion of a pin202into the socket204b, the compression system100may be used to form a thermal compression bond227between the pin202to the pad226. Compression of the elastomer206aof the surround structure206generates a spring force229that biases the contact layers212a-212d(212band212dshown) against the pin202.

Referring toFIG.8, a schematic cross-section diagram of an example implementation of a reversible attachment micro connector array200ais shown in accordance with one or more exemplary embodiments. The reversible attachment micro connector array200aincludes a first array of pins230on the first assembly140and a second array of sockets232on the second assembly160. The first array of pins230is generally mirrored by the second array of sockets232such that each pin202corresponds to a respective socket204. In various embodiments, the arrays may be one-dimensional arrays or two-dimensional arrays. A pitch234of the pins202and the socket204may be less than approximately 10 μm. A misalignment236between the first assembly140and the second assembly160while mated is at most 0.1 micrometers.

Referring toFIG.9, a plan diagram of an example implementation of an array of surround structures206is shown in accordance with one or more exemplary embodiments. Each surround structure206generally defines the cavity208and the tabs210a-210d. In some embodiments, each surround structure206defines an individual socket204(illustrated). In other embodiments, the surround structures206are a continuous sheet of material with the individual sockets204being defined by the cavities208. The socket layouts include an underlying daisy-chain fan-out for testing connection yields. Testing with arrays of tapered pins202aand the illustrated socket layouts and have shown the self-locating alignment and low resistance connections (e.g., approximately 0.4 ohm per link).

Referring toFIG.10, a perspective schematic of an example implantation of a tapered pin202ais shown in accordance with one or more exemplary embodiments. The pins202may be formed as tapered pins202a(illustrated), as straight pins202b, and as straight walled pins and tapered tops. For example, the tapered pins202amay have a tapered wall211. The designs for fine pitch designs generally keep the overall length of the pin202within a 3 μm to 5 μm range. A small taper angle for metallic spikes is approximately 65°. At such an angle, a 1.5 μm base spike with a 2 μm height is possible.

Referring toFIG.11, a perspective diagram of an example implementation of a polyimide pillars that will become a core of a straight pin202bis shown in accordance with one or more exemplary embodiments. A fabrication process for the straight pins202buses a polyimide as a core203and a tapered alignment tip on top. The core203generally forms a cylindrical wall213. The tapered tip is useful for self-location of the pins202in the sockets204. Self-alignment of the pins202in the socket204may result in a final alignment accuracy of less than approximately 0.1 μm.

Referring toFIG.12, and referring back toFIGS.2and3, a flow diagram of an example method280for reversible attachment connection is shown in accordance with one or more exemplary embodiments. The method280(or process) is implemented by the reversible attachment micro connector200. The method280generally includes steps282to308, as illustrated. The sequence of steps is shown as a representative example. Other step orders may be implemented to meet the criteria of a particular application.

In the step282, a pin202(or the first array of pins230) may be inserted into a socket204(or the second array of sockets232) a first time to establish an electrical connection205that mates the first assembly140with the second assembly160. The pin202engages the contact layers212a-212dcoupled to the tabs210a-210dof the socket204in the step284. During the insertion of the pin202, the tabs210a-210dand the contact layers212a-212dbend in the step286. The bending of the tabs210a-210dand the contact layers212a-212dmay be asymmetrical in a transverse direction through buckling instabilities in the step288.

In the step290, a stress distribution is generated with the negative longitudinal curvature214of the tabs210a-210dthat is uniform between the pin202and the tabs210a-210dwhile the pin202is seated in the socket204. The surround structure206that forms the tabs210a-210dbiases the contact layers212a-212dagainst the pin202in the step292with the spring force229provided by the elastomer206athat forms the tabs210a-210d. The stress distribution generally retains the pin202in the socket204in the step294.

In the step296, the pin202is removed from the socket204to separate the first assembly140from the second assembly160. During the removal of the pin202, the tabs210a-210dand the contact layers212a-212dbend in the step298. The bending of the tabs210a-210dand the contact layers212a-212dis asymmetrical in the transverse direction through buckling instabilities in the step300.

In the step302, the pin202is inserted back into the socket204a second time to reestablish the electrical connection205between the pin202and the socket204. The pin202may be optionally removed from the socket204a second time in the step304. If removed again, the pin202may be repeated inserted into and removed from the socket204until a final insertion in the step306to establish a mechanical connection between the pin202and the pad226. In the step308, a thermal compression bond is formed between the pin202and the pad226to mechanically secure the first assembly140to the second assembly160.

Embodiments of the disclosure generally provide fine-pitch (≤10 μm) reversible attachment micro connectors200that allow multiple attachment cycles for multi-dimensional array assemblies and stacked microelectronic assemblies. The reversible attachment micro connectors200are low insertion force connectors. The sockets204of the reversible attachment micro connectors200provide uniform stress distributions between socket sidewalls and the tapered pins202aor the straight pins202bduring insertion and seating. The sidewalls generally reduce or eliminate high-stress concentrations during connector assembly that lead to unwanted friction bonding or pin expulsion. The reversible attachment micro connectors200is tilt tolerant and generates similar contact pressures between the socket204and the pins202independent of insertion depth. The reversible attachment micro connectors200are self-aligning to provide sub-micron alignment accuracy of mated chip pairs through mechanical wedging.

The reversible attachment micro connectors200include a socket204with sidewalls that have a negative curvature (e.g., curves away from a center of the socket204). The negative curvature allows three-dimensional configurations (bending) to be developed during the insertion/removal of a pin202that gives rise to internal strain configurations that lead to sidewall buckling. Uniform stress distribution is provided while mating the sockets204with a tapered pin202aor a straight pin202b. Multiple connections and multiple disconnections are possible with the reversible attachment micro connectors200. Fine pitch multi-dimensional assemblies may be assembled, tested, disassemble, reassembled, and finally bonded together using the reversible attachment micro connectors200.

Clause 1. A reversible attachment micro connector comprising: a pin mounted on a first assembly; and a socket mounted on a second assembly, wherein: the socket is operational to mate with the pin at least two times to establish an electrical connection; the socket is operational to separate from the pin at least once; the socket includes a surround structure that defines a cavity with a floor; the cavity is sized to receive the pin; a plurality of tabs are disposed in the cavity and coupled to the surround structure; the plurality of tabs have a negative longitudinal curvature that protrudes into the cavity; the plurality of tabs bend in three dimensions during insertion of the pin202and removal of the pin; the negative longitudinal curvature generates a stress distribution that is uniform between the pin and the plurality of tabs while the pin is seated in the socket; and the pin is retained in the socket based on the stress distribution.

Clause 2. The reversible attachment micro connector according to clause 1, further comprising: a plurality of contact layers coupled to the plurality of tabs, made of metal, and operational to engage the pin.

Clause 3. The reversible attachment micro connector according to clause 2, wherein: the plurality of contact layers bend asymmetrically in a transverse direction through buckling instabilities during the insertion and the removal of the pin.

Clause 4. The reversible attachment micro connector according to clause 2 or clause 3, wherein: the stress distribution is within an elastic regime of the metal that forms the plurality of contact layers.

Clause 5. The reversible attachment micro connector according to clause 2 or clause 3, wherein: the plurality of contact layers is discontinuous around the cavity.

Clause 6. The reversible attachment micro connector according to clause 2 or clause 3, wherein: the plurality of contact layers is perpendicular to the floor of the cavity.

Clause 7. The reversible attachment micro connector according to clause 2 or clause 3, wherein: the surround structure and the plurality of tabs are formed of an elastomer.

Clause 8. The reversible attachment micro connector according to clause 7, wherein:

the elastomer provides a spring force that biases the plurality of contact layers against the pin.

Clause 9. The reversible attachment micro connector according to clauses 1 to 3, further comprising: a pad mounted on the floor of the socket, and operational to form a thermal compression bond with the pin.

Clause 10. The reversible attachment micro connector according to clauses 1 to 3, wherein: the pin has a tapered wall operational to engage the plurality of tabs.

Clause 11. The reversible attachment micro connector according to clauses 1 to 3, wherein: the pin has a cylindrical wall operational to engage the plurality of tabs.

Clause 12. The reversible attachment micro connector according to clauses 1 to 3, wherein: the first assembly includes a first array of pins; and the second assembly includes a second array of sockets.

Clause 13. A method for reversible attachment connection comprising: inserting a pin into a socket a first time to establish an electrical connection that mates a first assembly with a second assembly, wherein: the pin is mounted on the first assembly; the socket is mounted on the second assembly; the socket includes a surround structure that defines a cavity with a floor; a plurality of tabs is disposed in the cavity and coupled to the surround structure; and the plurality of tabs have a negative longitudinal curvature that protrudes into the cavity; bending the plurality of tabs in three dimensions during the inserting of the pin the first time; generating a stress distribution with the negative longitudinal curvature that is uniform between the pin and the plurality of tabs while the pin is seated in the socket; retaining the pin in the socket based on the stress distribution; removing the pin from the socket to separate the first assembly from the second assembly; bending the plurality of tabs in the three dimensions during the removing of the pin; and inserting the pin into the socket a second time to reestablish the electrical connection.

Clause 14. The method according to clause 13, further comprising: engaging the pin with a plurality of contact layers coupled to the plurality of tabs, wherein the plurality of contact layers are made of metal.

Clause 15. The method according to clause 14, further comprising: bending the plurality of contact layers asymmetrically in a transverse direction through buckling instabilities during the inserting of the pin the first time and the removing of the pin.

Clause 16. The method according to clause 13 to 15, further comprising:biasing a plurality of contact layers against the pin with a spring force provided by an elastomer that forms the plurality of tabs, wherein the plurality of contact layers are coupled to the plurality of tabs, made of metal, and operational to engage the pin.

Clause 17. The method according to clause 13 to 15, further comprising: forming a thermal compression bond between a pad mounted on the floor of the socket and the pin.

Clause 18. A reversible attachment micro connector array comprising: a first array of pins mounted on a first assembly; and a second array of sockets mounted on a second assembly, wherein the second array of sockets is operational to mate with the first array of pins at least two times to establish an electrical connection; the second array of sockets is operational to separate from the first array of pins at least once; individual sockets in the second array of sockets include a surround structure that defines a cavity with a floor; the cavity is sized to receive an individual pin of the first array of pins; a plurality of tabs are disposed in the cavity and coupled to the surround structure; the plurality of tabs have a negative longitudinal curvature that protrudes into the cavity; the plurality of tabs bend in three dimensions during insertion of the individual pin and removal of the individual pin; the negative longitudinal curvature generates a stress distribution that is uniform between the individual pin and the plurality of tabs while the individual pin is seated in the socket; and the individual pin is retained in the individual socket based on the stress distribution.

Clause 19. The reversible attachment micro connector array according to clause 18, wherein: a pitch of the second array of sockets is at most approximately 10 micrometers.

Clause 20. The reversible attachment micro connector array according to clause 18 or clause 19, wherein: a misalignment between the first assembly and the second assembly while mated is at most approximately 0.1 micrometers.

This disclosure is susceptible of embodiments in many different forms. Representative embodiments of the disclosure are shown in the drawings and are herein described in detail with the understanding that these embodiments are provided as an exemplification of the disclosed principles, not limitations of the broad aspects of the disclosure. To that extent, elements and limitations that are described, for example, in the Abstract, Background, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly or collectively, by implication, inference or otherwise.

For purposes of the present detailed description, unless specifically disclaimed, the singular includes the plural and vice versa. The words “and” and “or” shall be both conjunctive and disjunctive. The words “any” and “all” shall both mean “any and all”, and the words “including,” “containing,” “comprising,” “having,” and the like shall each mean “including without limitation.” Moreover, words of approximation such as “about,” “almost,” “substantially,” “approximately,” and “generally,” may be used herein in the sense of “at, near, or nearly at,” or “within 0-5% of,” or “within acceptable manufacturing tolerances,” or other logical combinations thereof. Referring to the drawings, wherein like reference numbers refer to like components.