Electrical Contact, Connector and Method for Manufacturing the Same

Abstract

The present application discloses an electrical contact and a connector for testing semiconductor devices such as integrated circuit packages, especially high-integration IC packages. The electrical contact includes a plurality of intertwined and mutually supporting filaments; wherein, the plurality of filaments includes at least one electrical conductor for providing a first electrical contact and a second electrical contact. The connector includes the electrical contact and a carrier having a plurality of through-holes; wherein, at least one of the electrical contacts is disposed in at least one of the through-holes. The present application also provides a method for manufacturing the electrical contact.

Description

Technical Field

[0001] This application relates to electrical contacts, also known as compliant electrical contacts, for integrated circuit (IC) packages, particularly for ultra-high density IC packages. This application also relates to a method of manufacturing such electrical contacts (i.e., manufacturing method), and a method of using such compliant electrical contacts (i.e., usage method). Additionally, this application relates to connectors employing such electrical contacts. Background Art

[0002] Currently, high-density IC packages are electrically connected to a substrate (e.g., a printed circuit board (PCB)) through a land grid array (LGA), pin grid array (PGA), or ball grid array (BGA) directly soldered to its bottom. Although the above direct soldering method has a low manufacturing cost, it has several significant drawbacks in detecting and correcting possible soldering failures. In addition, direct soldering permanently fixes the IC package to the substrate, so it is not suitable for testing the IC package. Summary of the Invention

[0003] To solve the above problems, this application discloses an electrical contact that does not need to be permanently fixed between the IC package and the substrate. Therefore, this electrical contact can be used both as a product socket for permanently connecting the IC package to the substrate and as a test socket for temporarily connecting the IC package to the substrate. Traditional electrical contacts need to use a dielectric mandrel to provide electrical energy storage; in contrast, the electrical contacts of this application can have only electrical wires. In other words, the wires have good electrical conductivity on the one hand and sufficient elasticity on the other hand, so that the electrical contacts will rebound to their initial state after being removed from the substrate and the IC package. In addition, the electrical contacts are also durable and can be tested for more than 500,000 life cycles.

[0004] In a first aspect, this application discloses an electrical contact. The electrical contact includes a plurality of interleaved (alternating, wound, interlaced, braided) and mutually supporting filaments. The interleaved and mutually supporting filaments include one or more electrical wires for providing a first electrical contact and a second electrical contact. By connecting a first external device (e.g., an IC package) and a second external device (e.g., a substrate) to the first electrical contact and the second electrical contact respectively, the first external device and the second external device are electrically connected to each other through the electrical contact. In some embodiments, the electrical contact includes six intertwined electrical wires. In other embodiments, the electrical contact includes eight intertwined electrical wires.

[0005] Optionally, the electrical wire includes a sharp edge for scraping the electrical contact surface of an external electrical device. In particular, the scraping is at the nanoscale (less than 1 micron). The scraping establishes a physical connection between the electrical contact and the external electrical device by removing contamination or oxidation on the contact surface of the external electrical device. The electrical wire may have a first tip and a second tip that form a first scrape and a second scrape at the first external electrical device and the second external electrical device, respectively, at the nanoscale. In some embodiments, the first tip or the second tip has a single sharp end for forming the scrape. In other embodiments, the first tip or the second tip has two or more minute protrusions for forming the scrape. At the same time, since the scraping is controlled at the nanoscale, the electrical wire does not damage the external electronic device. Thus, the first external electrical device and the second external electrical device can be reliably electrically connected by the electrical wire of the electrical contact.

[0006] Optionally, the plurality of filaments includes three or more independent wire materials that are interleaved and support each other to form an integral structure. The independent wire materials (including the electrical wire) are not supported by any other object and are independent of each other. In this way, the independent wire materials can move within a limited range while still maintaining the integral structure. In other words, the integral structure can undergo elastic deformation. In particular, the integral structure undergoes non-uniform elastic deformation along its axial direction. The first part and the second part respectively near the first tip and the second tip of the electrical wire have larger elastic deformations; while the intermediate part between the first part and the second part has a smaller elastic deformation.

[0007] The integral structure includes a tubular structure (such as the wall or shape of a cylinder). The tubular structure includes one or more open ends that have the sharp edges. The tubular structure has spring characteristics for reversibly storing and releasing mechanical energy. In other words, the tubular structure can be longitudinally compressed from an initial position under the action of an axial load and then substantially rebound to the initial position after the axial load is removed. During the elastic deformation process, each independent wire material only exhibits bending characteristics consistent with the elastic limit portion of the "stress-strain" or "force-deformation" curve of the material that constitutes it.

[0008] In some embodiments, the wires are formed into a helical configuration by interweaving independent wires adjacent to each of the tubular structures. The characteristics of the tubular structure can be characterized by the tubular diameter, pitch, or lead. The compression ratio of the tubular structure in its cylindrical or longitudinal direction does not exceed 30%. In other words, under the action of an axial load, the minimum compressed length needs to be at least greater than 70% of the initial length without an axial load for the tubular structure to maintain elastic deformation.

[0009] Every two of the independent wires cross and support each other, forming an intersection point (i.e., intersecting and contacting each other, but not connected) on the cylindrical wall of the tubular structure. As described above, the two independent wires are not coupled or bonded at their intersection points; thus, at the intersection points, one independent wire can move relative to another independent wire that crosses it. Additionally, the tubular structure has one or more of the leads. The lead is defined as the distance between a first intersection point and a second intersection point in the axial plane of the same wire. That is, the wire starts winding around the tubular structure from the first intersection point in an axial plane and then ends at the second intersection point in that axial plane.

[0010] Each of the independent wires crosses another wire, forming at least one of the intersection points. The distance between two adjacent intersection points along the axial or cylindrical direction of the tubular structure is called the pitch. In some embodiments, the pitch is substantially the same. In some embodiments, when the tubular structure has eight wires that cross and support each other, the lead has four pitches in the axial plane. Therefore, the lead of the wire is equal to the span of four pitches in the axial plane. The tubular structure can be measured by the lead or the pitch. Optionally, when the initial length of the tubular structure in the non-compressed state is in the range of 50 to 100 mils, it can form compact and self-supporting properties. The tubular structure has a flexible design in terms of the tubular diameter, lead, and wire diameter of the wires. In some embodiments, the wire diameter is about 1.2 mils; and when the leads are set to 25 mils, 26 mils, and 30 mils, the tubular diameters are selected to be 5 mils, 6 mils, and 8 mils, respectively. In other embodiments, the wire diameter is about 0.85 mils; and when the lead is set to about 15 mils, the tubular diameter is selected to be about 3 mils.

[0011] In the absence of external forces (i.e., at the initial position or under the influence of gravity only), two or more intersecting said wire rods form an angle that is approximately a right angle between them. The angle formed by the two wire rods at the intersection may vary slightly because the two wire rods can move around the intersection. The angle has a variation within 10 degrees, i.e., from 80 degrees to 100 degrees. After removing the axial load, the right angle can help the tubular structure rebound to the initial position (i.e., the initial position).

[0012] The electrical wire is the most critical factor for the electrical contact to electrically connect the first external device and the second external device. Therefore, the electrical wire is required to have various properties, such as high electrical conductivity (or low resistance), high durability under repeated flexure, the ability to transmit high-frequency signals, the ability to withstand gradually increasing operating temperatures, stable chemical properties (e.g., not easily oxidized in the surrounding environment), and high mechanical strength. Optionally, the electrical wire includes a multi-layer structure with different materials. Due to this unique multi-layer structure, the electrical wire has a sufficiently large elastic range. In addition to the unique multi-layer structure, the electrical wire can also be subjected to an annealing process to expand its elastic range.

[0013] Optionally, the multi-layer structure may include an inner layer having an elastic or flexible material; and a covering layer for covering the inner layer to prevent at least one electrical wire in the wire from being corrosion-resistant (e.g., oxidized) or enhancing its electrical conductivity. When the covering layer is formed by electroplating, the covering layer is also called a plating layer. Additionally, the inner layer also provides the mechanical strength for maintaining the integrity of the wire. In some embodiments, the inner layer includes a steel material, such as stainless steel (e.g., stainless steel 302, 304, or 316), spring steel, memory steel, and other similar shape memory alloys (e.g., nickel-titanium (also known as nitinol)). In other embodiments, the inner layer includes a metal with a very low resistivity (e.g., copper) for enhancing the electrical conductivity of the electrical wire.

[0014] Optionally, the covering layer further includes: a nickel (Ni) layer (e.g., nickel plating layer) plated on the inner layer for covering the inner layer; and a gold layer (e.g., gold plating layer) plated on the nickel layer for encapsulating the nickel layer. The nickel layer and the gold layer are also used to further enhance the electrical conductivity of the electrical contact because the resistivity of nickel and gold at room temperature (i.e., 20 °C) is approximately 6.99x10 -8 ohm meters (Ω·m) (i.e., the electrical conductivity is approximately 14.3 million siemens per meter (siemens permeter)) and 2.44x10 -8Ohmmeter (Ω·m) (i.e., the conductivity is approximately 41.1 million siemens per meter). Additionally, the gold layer can also prevent the inner layer and the nickel layer from oxidizing. In some embodiments, before forming the gold layer, a palladium (Pd) layer (such as a palladium plating layer) is first formed on the nickel layer. In other words, the palladium layer is located between the nickel layer and the gold layer. Since the conductivity of palladium at room temperature (i.e., 20 °C) is approximately 1.06x10 -8 Ohmmeter (Ω·m) (i.e., the conductivity is approximately 9.43 million siemens per meter), so the palladium layer further reduces the resistivity; and also provides additional mechanical strength (such as hardness) for the covering layer. In particular, the thickness of the gold layer is greater than 1.0 micrometer (μm); while the thicknesses of the nickel layer and the palladium layer are both less than 1.0 micrometer (μm).

[0015] Optionally, the covering layer further includes a copper layer (such as a copper plating layer) formed on the inner layer to cover the inner layer, especially when the inner layer is made of a non - copper alloy. Since stainless steel has a relatively high resistivity of 6.90x10 -7 Ohmmeter (Ω·m) (i.e., the conductivity is approximately 1.4 million siemens per meter) at room temperature (i.e., 20 °C), so the copper layer can be used to enhance the conductivity of the electrical contact. The resistivity of copper at room temperature (i.e., 20 °C) is 1.68x10 -8 Ohmmeter (Ω·m) (i.e., the conductivity is approximately 60 million siemens per meter). Optionally, high - performance copper or high - strength copper (such as C17510 copper alloy) is used to enhance the conductivity. Similarly, the thickness of the copper layer can be greater than 2.0 micrometer (μm).

[0016] Optionally, the multilayer structure further includes an outer layer for encapsulating the inner layer and / or the cover layer to prevent corrosion of the inner layer and / or the cover layer. In some embodiments, the outer layer includes a self-assembled monolayer (SAM) layer. The self-assembled monolayer includes a plurality of multifunctional molecules having a fixing group for connecting to the cover layer and a plurality of functional groups opposite to the fixing group, and the multifunctional molecules can enhance corrosion resistance and wear resistance. If electrons can be transferred between the multifunctional molecules, the self-assembled monolayer can provide additional conductivity for the electrical wire; thus, a conductive path is formed between adjacent electrical wires in direct contact. If electrons cannot be transferred between the multifunctional molecules, such a conductive path will not be formed, and the adjacent electrical wires are insulated from each other. In some embodiments, the self-assembled monolayer is formed on the cover layer, so the self-assembled monolayer prevents oxidation of the cover layer; thus, the gold layer can have a thinner thickness to save costs. In some embodiments, the self-assembled monolayer is directly formed on the inner layer to prevent oxidation of the inner layer. Optionally, the self-assembled monolayer is less than 0.5 micrometers (μm). Alternatively, the outer layer includes a parylene coating, which has excellent pore-free and uniform barrier properties against various chemicals (such as organic solvents, inorganic reagents, acids, oxygen, corrosive liquids and gases, and moisture). Additionally, the parylene coating also has excellent electrical insulation properties and a low dielectric constant.

[0017] Optionally, the multilayer structure further includes an insulating layer that completely or partially wraps, surrounds, encapsulates, covers the cover layer. The cover layer is exposed from within the insulating layer at the first and second ends of the electrical contact. The insulating layer can prevent electrical interference between adjacent electrical contacts to enhance signal transmission. The insulating layer can be made of any insulating material, including but not limited to fiberglass, mineral wool, cellulose, natural fibers, synthetic polymers (such as polystyrene, polyisocyanurate, and polyurethane), or synthetic foams (such as urea-formaldehyde foam, cement foam, and phenolic foam).

[0018] Optionally, the wire further includes one or more support wires for supporting other wires (such as electrical wires). The support wires are also wound in a similar manner (such as a helical path) and intertwined with the other wires (such as electrical wires) to form the overall structure.

[0019] Second aspect, the present application discloses a connector. The connector includes a plurality of the electrical contacts; and a carrier (also referred to as a housing) having a plurality of through-holes. The carrier is disposed between a first external electronic device (such as an IC package) and a second external electronic device (such as a substrate). The plurality of electrical contacts are respectively placed in the plurality of through-holes for electrically connecting the first external electrical device and the second external electrical device. The first end and / or the second end of the plurality of electrical contacts protrude from the through-holes. In other words, the electrical contacts have an initial length in an initial position; and the through-holes have a through-hole depth. The initial length must be greater than the through-hole depth. The diameter of the through-hole (through-hole diameter) is slightly larger than the diameter of the electrical contact for guiding the electrical contact into the through-hole.

[0020] Optionally, the through-holes are arranged in an array corresponding to the external electrical devices. The connector may further include a plurality of fasteners for fixing, attaching or fastening the housing to the external electrical devices. For example, the connector includes a first fastener for fixing the housing to the first external electrical device after the electrical contacts are precisely aligned with the first external electrical device. Similarly, the connector further includes a second fastener for fixing the housing to the second external electrical device after the electrical contacts are precisely aligned with the second external electrical device. Thus, an effective path for transmitting electrical signals from the first external electrical device to the second external electrical device is established through the connector.

[0021] Optionally, the carrier or housing includes a top layer, a bottom layer, and an intermediate layer sandwiched between the top layer and the bottom layer. The carrier can be used as an interposer for accommodating the electrical contacts and providing mechanical support for them. Optionally, the top layer is made of an insulating material (such as polyimide). Optionally, the bottom layer is also made of an insulating material (such as polyimide). Optionally, the intermediate layer is made of a heat-conducting material (such as copper). Thus, the intermediate layer can be used as a heat sink for dissipating the heat generated by the electrical contacts. The carrier may further include a top intermediate layer between the top layer and the intermediate layer for joining the top layer and the intermediate layer; and a bottom intermediate layer between the bottom layer and the intermediate layer for joining the bottom layer and the intermediate layer. Additionally, the top intermediate layer may further include a top adhesive layer (such as pure silicone); the bottom intermediate layer may further include a bottom adhesive layer (such as pure silicone). Under heating and pressurization conditions, pure silicone combines the top layer, the intermediate layer, and the bottom layer into a single structure.

[0022] Third aspect, the present application discloses a method for manufacturing the above electrical contacts (i.e., manufacturing method). The manufacturing method includes the following steps: a step of providing a plurality of wire-like materials, which includes one or more electrical conductors; a step of intertwining, alternating, winding, and braiding the plurality of wire-like materials to form an integral structure; a step of separating (e.g., cutting) the integral structure into a plurality of substantially identical or similar electrical contacts; and a step of plating the electrical contacts to form a multi-layer structure. The at least one electrical conductor has a first electrical contact and a second electrical contact opposite thereto. In other words, the electrical conductors respectively have a first electrical contact and a second electrical contact around their first ends and second ends. Optionally, a knitting machine is used to intertwine the wire-like materials. In some embodiments, the wire-like materials are configured to form a spiral structure for forming the integral structure. The intertwining step can be performed vertically or horizontally.

[0023] Optionally, the method for manufacturing the electrical contacts includes the following steps: a step of providing a plurality of wire-like materials, the plurality of wire-like materials including one or more electrical conductors; a plating step for forming a multi-layer structure of the electrical conductors; a step of intertwining, alternating, winding, and braiding to form the integral structure; and a step of separating (e.g., cutting) the integral structure to form a plurality of substantially identical or similar electrical contacts.

[0024] Optionally, the method for manufacturing the electrical contacts further includes the following steps: after the intertwining step (e.g., annealing process), first heating the integral structure to eliminate the internal stress of the above electrical conductors during the heating process; and then cooling the integral structure to room temperature. Optionally, the heating step is performed by a thermal radiation process. Heat is transferred from the thermal radiation source to the integral structure until the integral structure is heated to 200 to 500 degrees Celsius and maintained for about 5 minutes. During the thermal radiation heating process, the integral structure does not come into direct physical contact with the thermal radiation source, so that the integral structure can be configured to be heated substantially uniformly. In addition, the thermal radiation process is performed in an inert environment (e.g., the chamber is filled with nitrogen).

[0025] Optionally, since the integral structure has ferromagnetic properties, the heating step can be performed by an induction heating process. The induction heater generates eddy currents to generate heat inside the electrical conductors of the integral structure. The induction heating process has at least the following advantages. First, the induction heating process can be carried out very quickly. Second, the induction heating process does not involve any foreign substances, so it can be carried out in an ordinary environment. Third, the induction heating process can be targeted or concentrated on the integral structure, so the integral structure can be heated very uniformly. In addition, the induction heating process can of course also be carried out in an inert environment.

[0026] Optionally, the electrical wire may be prepared by the following steps: a step of providing an inner layer as a wire core; a step of forming at least one covering layer (such as a plating layer) for encapsulating the inner layer; the covering layer is formed by the following steps: a step of plating a copper layer on the inner layer to seal the inner layer; a step of plating a nickel layer on the copper layer to cover the copper layer; and a step of plating a gold layer on the nickel layer to cover the nickel layer. Optionally, the manufacturing method of the electrical contact may further include a step of forming a palladium layer between the nickel layer and the gold layer.

[0027] Optionally, the manufacturing method of the electrical contact may further include: a step of forming an outer layer on the covering layer for encapsulating the covering layer. Optionally, the outer layer includes a self-assembled monolayer (SAM) layer. For example, the self-assembled monolayer (SAM) layer is formed by immersing the electrical wire in a precursor solution of multifunctional molecules. The multifunctional molecules will spontaneously fix on the covering layer and arrange in a certain configuration rule. Optionally, the covering layer includes a parylene coating. For example, a parylene coating (i.e., a parylene layer) formed by a parylene deposition process. The deposition process of parylene requires three stages to complete. In the first stage (i.e., the vaporization stage), the powdered parylene dimer is added to a vaporizer and then heated to 150 °C to make it into a vapor state. In the second stage (i.e., the pyrolysis stage), the parylene dimer vapor is transferred to a pyrolysis furnace and then heated to 690 °C at a pressure of 0.5 Torr (about 67 Pascals) to form parylene monomers. In the third stage (i.e., the deposition stage), before introducing the parylene monomers into the coating chamber, the electrical wire is first placed in the coating chamber. A part of the parylene monomers forms a polymer of parylene and is simultaneously deposited and fixed on the outer surface of the electrical wire. Optionally, the parylene deposition process may further include a fourth stage: discharging the excess parylene monomers from the coating chamber to an external liquid cold trap.

[0028] Alternatively, the manufacturing method of the electrical contact may further include: a step of forming an insulating layer on the covering layer and / or the outer layer. Optionally, the insulating layer is formed by winding an insulating sheet on the covering layer and / or the outer layer.

[0029] Fourth aspect, the present application discloses a method of using the above electrical contact (i.e., the usage method). The usage method includes: a step of providing one or more of the electrical contacts; a step of disposing the electrical contact on or within a second external electrical device; and a step of disposing a first external electronic device on the electrical contact. The electrical contact is slightly compressed between the first external electrical device and the second external electrical device, and its compression length does not exceed 30%. In particular, the electrical contact is very strong and can almost completely return to the uncompressed state when the first external electrical device and the second external electrical device are removed. Therefore, the electrical contact can be used as a product socket or a test socket.

[0030] The electrical contact has a first end and a second end opposite thereto, which are in direct contact with the first external electrical device and the second external electrical device respectively. At least one of the first end and the second end is configured to scratch the surfaces of the first external electrical device and the second external electrical device respectively at the nanoscale to form a reliable electrical contact.

[0031] Optionally, the usage method of the electrical contact may further include: a step of providing a carrier (or housing) having one or more through holes; a step of placing the carrier on the second external electrical device; and a step of inserting the electrical contact into the through hole.

[0032] Optionally, the usage method of the electrical contact may further include: a step of fixing the carrier to the first external electrical device and / or the second external electrical device. Before performing the fixing step, the electrical contact is precisely aligned with the first external electrical device and / or the second external electrical device.

[0033] Optionally, the usage method of the electrical contact may further include: a step of providing an electrical contact pad between the electrical contact and the first external electrical device and / or the second electrical device. The electrical contact pad (e.g., a solder pad or a copper pillar) can further provide a good and reliable electrical connection between the electrical contact and the first external electronic device and / or the second external electronic device.

[0034] Fifth aspect, the present application discloses a method of manufacturing a carrier for the electrical contact (i.e., the carrier manufacturing method). The carrier manufacturing method includes: a step of providing a top layer, an intermediate layer, and a bottom layer; a step of aligning and stacking the top layer, the intermediate layer, and the bottom layer; a step of assembling the top layer, the bottom layer, and the intermediate layer into the carrier, the carrier forming a single integral structure; and a step of forming a plurality of through holes in the top layer, the intermediate layer, and the bottom layer.

[0035] Optionally, the method for manufacturing the carrier may further include: providing the top intermediate layer and the bottom intermediate layer; stacking the top intermediate layer between the top layer and the intermediate layer; stacking the bottom intermediate layer between the intermediate layer and the bottom layer; and assembling the top intermediate layer and the bottom intermediate layer together with the top layer, the intermediate layer, and the bottom layer.

[0036] Alternatively, the method for manufacturing the carrier includes: providing a top layer having a plurality of first through-holes; providing an intermediate layer having a plurality of second through-holes; providing a bottom layer having a plurality of third through-holes; aligning the top layer, the intermediate layer, and the bottom layer by aligning the first through-holes, the second through-holes, and the third through-holes; and assembling the top layer, the intermediate layer, and the bottom layer into a single structure.

[0037] Optionally, the method for manufacturing the carrier may further include: providing a top intermediate layer having a fourth through-hole; providing a bottom intermediate layer having a fifth through-hole; aligning the top intermediate layer with the top layer and the intermediate layer by aligning the fourth through-hole with the first through-hole and the second through-hole; aligning the bottom intermediate layer with the intermediate layer and the bottom layer by aligning the fifth through-hole with the second through-hole and the third through-hole; and assembling the top intermediate layer and the bottom intermediate layer together with the top layer, the intermediate layer, and the bottom layer.

[0038] In a sixth aspect, the present application discloses a method of using the electrical contact device (i.e., the method of using the electrical contact device). The method of using the electrical contact device includes: providing a first external electrical device and a second external electrical device; connecting the electrical contact device to the second external electrical device; and connecting the first external electronic device to the electrical contact device.

[0039] Optionally, the method of using the electrical contact device may further include the steps of: aligning the electrical contact device with the top contact pad of the second external electrical device; and aligning the electrical contact device with the bottom contact pad of the first external electrical device.

[0040] Optionally, the electrical contact device may be prepared by the following steps: providing a carrier having a plurality of through-holes; providing a plurality of electrical contacts; assembling the electrical contacts with the carrier; and transferring the electrical contact device to the second external electrical device. The assembling includes inserting the electrical contacts into their respective through-holes. The inserting step can be performed by any known method. Optionally, the electrical contact device may also be prepared by the following steps: providing a carrier having a plurality of through-holes; providing a plurality of electrical contacts; placing the carrier on the second external electronic device; and assembling the electrical contacts with the carrier. Brief Description of the Drawings

[0041] The following drawings (figures) illustrate embodiments and are used to explain the principles of the disclosed embodiments. However, it should be understood that these figures are given for illustrative purposes only and are not intended to limit the relevant features.

[0042] Figure 1 Perspective view showing an electrical contact in an initial state;

[0043] Figure 2 Side view showing the electrical contact in the initial state;

[0044] Figure 3 Top view showing the electrical contact in the initial state;

[0045] Figure 4 Enlarged perspective view showing the tip of the electrical contact;

[0046] Figure 5 Side view showing a solder ball mounted at the tip of the electrical contact;

[0047] Figure 6 Showing in the initial state ( Figure 6 (a)) and in a compressed state ( Figure 6 (b)) side view of the electrical contact;

[0048] Figure 7 Top view showing another electrical contact having two types of electrical leads;

[0049] Figure 8 Cross-sectional view showing a first embodiment of the electrical lead;

[0050] Figure 9 Cross-sectional view showing a second embodiment of the electrical lead;

[0051] Figure 10 Cross-sectional view showing a third embodiment of the electrical lead;

[0052] Figure 11 Cross-sectional view showing a fourth embodiment of the electrical lead;

[0053] Figure 12 Exploded perspective view showing a first connector;

[0054] Figure 13 Cross-sectional view showing the first connector;

[0055] Figure 14 Exploded perspective view showing a second connector;

[0056] Figure 15Shows a cross-sectional view of the second connector;

[0057] Figure 16 Shows a process flow diagram for the treatment of the electrical contact;

[0058] Figure 17 Shows a process flow diagram for forming the plating layer of the electrical contact.

[0059] The reference numerals in the figure are indicated as follows:

[0060] 100, electrical contact; 102, first electrical wire; 103, second electrical wire; 104, third electrical wire; 105, fourth electrical wire; 106, fifth electrical wire; 107, sixth electrical wire; 108, seventh electrical wire; 109, eighth electrical wire; 110, overall structure; 112, intersection point; 114, pitch; 116, initial diameter; 118, initial length; 120, repeat distance; 122, tip; 126, IC device; 128, printed circuit board (PCB); 130, inner layer; 132, plating layer; 134, copper plating layer; 136, nickel plating layer; 138, palladium plating layer; 140, gold plating layer; 142, self-assembled monolayer (SAM) layer; 143, parylene coating; 144, initial state; 146, compressed state; 147, compressed length; 148, solder ball; 152, first top sharp end; 153, second top sharp end; 154, third top sharp end; 155, fourth top sharp end; 156, fifth top sharp end; 157, sixth top sharp end; 158, seventh top sharp end; 159, eighth top sharp end; 160, first embodiment of the electrical wire; 170, second embodiment of the electrical wire; 180, third embodiment of the electrical wire; 190, fourth embodiment of the electrical wire;

[0061] 200, elastic electrical contact; 202, first electrical wire; 203, second electrical wire; 204, third electrical wire; 205, fourth electrical wire; 206, fifth electrical wire; 207, sixth electrical wire; 208, seventh electrical wire; 209, eighth electrical wire; 210, overall structure;

[0062] 300, First electrical contact system; 302, Carrier; 304, Through-hole; 314, Top layer; 316, Intermediate layer; 318, Bottom layer; 320, First through-hole; 322, Second through-hole; 324, Third through-hole; 326, Printed circuit board groove; 328, First hole; 330, Second hole; 332, Third hole; 334, Top layer groove; 350, Second electrical contact system; 352, Carrier (housing); 354, Through-hole; 364, Top layer; 366, Intermediate layer; 368, Bottom layer; 370, First through-hole; 372, Second through-hole; 374, Third through-hole; 378, First hole; 380, Second hole; 382, Third hole;

[0063] 400, Processing flowchart of electrical contact 100; 410, First step; 420, Second step; 430, Third step; 440, Fourth step; 450, Fifth step;

[0064] 500, Processing flowchart of coating; 510, First step; 520, Second step; 530, Third step; 540, Fourth step; 550, Fifth step. Detailed implementation

[0065] Figures 1 to 6 Represents electrical contact 100 with a single type of electrical wire (referred to as the first type of electrical wire). Figure 1 Represents a perspective view of electrical contact 100 in an initial state. The electrical contact 100 includes eight intertwined or braided and unsupported electrical wires 102 - 109, namely the first electrical wire 102, the second electrical wire 103, the third electrical wire 104, the fourth electrical wire 105, the fifth electrical wire 106, the sixth electrical wire 107, the seventh electrical wire 108, and the eighth electrical wire 109. The eight electrical wires 102 - 109 are intertwined with each other in a helical configuration to form an overall structure 110 in a tubular configuration. In particular, the overall structure 110 does not require a central support structure around which the electrical wires 102 - 109 are wound, nor does it require a support structure outside or inside which the electrical wires 102 - 109 are placed. The electrical wires 102 - 109 belong to the first type of electrical wire, which are basically the same in terms of material, size, and other aspects.

[0066] Figure 2A side view showing the electrical contact 100 in its initial state. In the overall structure 110, every two of the eight electrical wires 102 - 109 overlap to form an intersection 112. Thus, the overall structure 110 includes a plurality of intersections 112. The electrical wires 102 - 109 overlap at the intersections 112. At the intersections 112, there is no physical, chemical, or mechanical bonding or interconnection. Therefore, the electrical wires 102 - 109 can move freely at the intersections 112. The overall structure 110 has an initial length 118 when it is in the initial state. In contrast, the pitch 114, which is defined as the distance between two adjacent intersections 112, is more commonly used to characterize the overall structure 110. Since the electrical wires 102 - 109 can move at the intersections 112, the pitch 114 can be adjusted within a small range without damaging the overall structure 110. In particular, when in the initial state, the angle formed by two of the electrical wires 102 - 109 at each intersection 112 is substantially a right angle (90 degrees). This right angle helps the overall structure 110 bounce back from the compressed state to the initial state and form a stable structure in the initial state. Additionally, the overall structure 110 has a special parameter called the repeat distance 120. The repeat distance 120 is determined by measuring the distance between two adjacent intersections 112 of a single electrical wire 102 - 109 in the axial plane. In the initial state, the repeat distance 120 is limited to less than 90 mils to keep the overall structure 110 more stable.

[0067] Figure 3 A top view showing the electrical contact 100 in its initial state. The overall structure 110 has an initial diameter 116 at its top end 122. Figure 3 It is also clearly shown that there is no central support structure inside the overall structure 110, and the eight electrical wires 102 - 109 are intertwined. The overall structure 110 also has a bottom end (not shown) opposite to the top end 122. The bottom end has a structure similar to that of the top end 122. The top end 122 and the bottom end will be electrically connected to an IC device 126 as a first external electrical device and a printed circuit board (PCB) 128 as a second external electrical device, respectively. The electrical contact 100 has a very high bulk conductivity (i.e., a very low bulk resistivity), such that the IC device 126 and the printed circuit board 128 are effectively electrically connected through the electrical contact 100. Optionally, the bulk conductivity is in the range of 10 to 30 milliohms.

[0068] Figure 4An enlarged perspective view showing the tip 122 of the electrical contact 100. Each of the eight electrical wires 102 - 109 has a sharp tip at its tip 122. Specifically, the first electrical wire 102 has a first sharp tip 152, the second electrical wire 103 has a second sharp tip 153, the third electrical wire 104 has a third sharp tip 154, the fourth electrical wire 105 has a fourth sharp tip 155, the fifth electrical wire 106 has a fifth sharp tip 156, the sixth electrical wire 107 has a sixth sharp tip 157, the seventh electrical wire 108 has a seventh sharp tip 158, and the eighth electrical wire 109 has an eighth sharp tip 159. Similarly, each of the eight electrical wires 102 - 109 also has a sharp bottom end at its second end.

[0069] Figure 5 A side view showing the solder ball 148 mounted at the tip 122 of the electrical contact 100. Figure 5 It is clearly shown that the sharp tips 152 - 159 at the tip 122 scratch the solder ball 148 multiple times at the nanoscale (less than 1 micrometer). The electrical wires 102 - 109 are slightly bent inside the solder ball 148 at their tip 122 so that the solder ball 148 is not severely damaged by the electrical wires 102 - 109. In this way, the electrical contact 100 makes physical contact with the solder ball 148 at the tip 122. Therefore, a reliable electrical connection is established between the electrical contact 100 and the solder ball 148 regardless of whether the outer surface of the solder ball 148 is contaminated. Since the solder ball 148 is further attached to the IC device 126, the electrical contact 100 also establishes a reliable electrical connection with the IC device 126. Similarly, the bottom end also has sharp tips for forming scratches at the nanoscale. Therefore, a reliable electrical connection is established between the electrical contact 100 and the printed circuit board 128. Overall, current freely flows from the IC device 126 to the printed circuit board 128 through the electrical contact 100.

[0070] Figure 6 Showing the electrical contact 100 in the initial state ( Figure 6 (a)) and in the compressed state ( Figure 6 (b)) side views. When an axial load or force is applied longitudinally, the overall structure 110 undergoes axial deformation from the initial state 144 to the compressed state 146. As Figure 6As shown in (b), the deformation experienced by the electrical conductors 102 - 109 during compression is basically elastic, that is, the electrical conductors 102 - 109 will only exhibit bending characteristics that are exactly consistent with the elastic limit part of the "stress - strain" or "force - deformation" curve of the material constituting them. In other words, the electrical conductors 102 - 109 basically do not produce plastic deformation during compression. Generally, the electrical contact 100 has a compression length 147 in the compressed state 146. The typical compression ratio of the overall structure 110 does not exceed 30%. In other words, the compression length 147 is not less than 70% of the initial length 118.

[0071] Figure 7 A top view showing another electrical contact 200, which has two types of electrical conductors. The electrical contact 200 has a first electrical conductor 202, a second electrical conductor 203, a third electrical conductor 204, a fourth electrical conductor 205, a fifth electrical conductor 206, a sixth electrical conductor 207, a seventh electrical conductor 208, and an eighth electrical conductor 209. The electrical contact 200 has a structure similar to that of the electrical contact 100, except that the electrical contact 200 has two types of electrical conductors. Specifically, the electrical conductors 203, 205, 206, 208 belong to the first type; the electrical conductors 202, 204, 207, 209 belong to the second type. The electrical conductors 202 - 209 are also wound and intertwined in a helical configuration to form an overall structure 210. In particular, the first - type electrical conductors 203, 205, 206, 208 include stainless steel or shape - memory steel to provide additional spring properties for helping the electrical contact 200 to rebound to the initial position after the axial load is removed; while the second - type electrical conductors 202, 204, 207, 209 include copper or other metals with high electrical conductivity to provide sufficient electrical conductivity to the electrical contact 200.

[0072] Figure 8 A cross - sectional view showing the first embodiment 160 of the electrical conductors 102 - 109. Figure 8 (a) is a cross - sectional view along the longitudinal axis; and Figure 8 (b) represents a cross - sectional view perpendicular to the longitudinal axis. The electrical conductors 102 - 109 include an inner layer or core layer 130 and a plating or covering layer 132. The plating 132 basically completely encapsulates the inner layer 130 inside the electrical conductors 102 - 109. The diameter of the inner layer 130 is 0.3 to 5 mils. The thickness of the plating 132 is 0.1 to 0.5 mils. The inner layer 130 is made of stainless steel with a cubic crystal structure. The variation of the cubic crystal structure (such as face - centered cubic) provides sufficient ductility for the stainless steel to allow elastic bending of the inner layer 130 when the electrical conductors 102 - 109 are wound or braided into a tubular overall structure 110.

[0073] From the inside to the outside of the first electrical wire 102, the coating layer 132 further includes, respectively: a copper coating layer 134, a nickel coating layer 136, a palladium coating layer 138, and a gold coating layer 140. The copper coating layer 134, the nickel coating layer 136, the palladium coating layer 138, and the gold coating layer 140 have a first thickness greater than 2.0 micrometers (μm), a second thickness greater than 1.0 micrometer, a third thickness less than 1.0 micrometer, and a fourth thickness greater than 1.0 micrometer, respectively.

[0074] Figure 9 A cross-sectional view showing a second embodiment 170 of the electrical wires 102 - 109. Figure 9 (a) is a cross-sectional view along the longitudinal axis; and Figure 9 (b) is a cross-sectional view perpendicular to the longitudinal axis. The second embodiment 170 has a structure similar to that of the first embodiment 160, except that the electrical wires 102 - 109 further include a self-assembled monolayer (SAM) layer 142 for preventing oxidation of the coating layer 132 and the inner layer 130. The thickness of the self-assembled monolayer 142 is less than 0.5 micrometers (μm). Moreover, the inner layer 130 can be made of a copper alloy instead of stainless steel.

[0075] Figure 10 A cross-sectional view showing a third embodiment 180 of the electrical wires 102 - 109. Figure 10 (a) is a cross-sectional view along the longitudinal axis; and Figure 10 (b) is a cross-sectional view perpendicular to the longitudinal axis. The third embodiment 180 has a structure similar to that of the second embodiment 170, except that the electrical wires 102 - 109 include a parylene coating 143 to replace the self-assembled monolayer 142. The thickness of the parylene coating 143 is less than 0.5 micrometers (μm). Moreover, the inner layer 130 can be made of a copper alloy instead of stainless steel.

[0076] Figure 11 A cross-sectional view showing a fourth embodiment 190 of the electrical wires 102 - 109. Figure 11 (a) is a cross-sectional view along the longitudinal axis; and Figure 11 (b) is a cross-sectional view perpendicular to the longitudinal axis. Similarly, the electrical wires 102 - 109 include an inner layer 130 and a coating layer 132. However, the coating layer 132 only includes a self-assembled monolayer (SAM) layer 142 directly on the inner layer 130 for preventing oxidation of the inner layer 130. The self-assembled monolayer 142 also has a thickness less than 0.5 micrometers (μm). Additionally, the inner layer 130 is only made of a copper alloy.

[0077] Figure 12Shows an exploded perspective view of the first connector 300. The first connector 300 includes a plurality of electrical contacts 100, 200 and a housing or carrier 302 defining a plurality of through-holes 304. The plurality of electrical contacts 100, 200 are respectively placed in their corresponding through-holes 304. The carrier 302 has a sandwich structure that includes a top layer 314, a bottom layer 318, and an intermediate layer 316 located between the top layer 314 and the bottom layer 318. The top layer 314 and the bottom layer 318 are made of an insulating material, such as polyimide; while the intermediate layer 316 is made of copper or a copper alloy. Thus, the through-hole 304 has a first through-hole 320, a second through-hole 322, and a third through-hole 324 respectively on the entire top layer 314, intermediate layer 316, and bottom layer 318. The first through-hole 320, the second through-hole 322, and the third through-hole 324 are precisely aligned to form the through-hole 304. The printed circuit board 128 also has a plurality of printed circuit board grooves 326, aligned with their respective through-holes 320-324, for guiding and receiving the electrical contacts 100, 200. In addition, a first hole 328, a second hole 330, and a third hole 332 are respectively distributed at the peripheral positions of the top layer 314, intermediate layer 316, and bottom layer 318. The top layer 314, intermediate layer 316, and bottom layer 318 are also integrally combined into the carrier 302 by using carrier fasteners (such as bolts or screws) passing through the first hole 328, the second hole 330, and the third hole 332. Additionally, the carrier 302 further includes a top fastener (such as a top buckle) (not shown) and a bottom fastener (such as a bottom buckle) (not shown) for respectively fixing the carrier 302 to the IC device 126 and the printed circuit board 128. Thus, the IC device 126 and the printed circuit board 128 can be precisely aligned with the electrical contacts 100, 200 in the carrier 302 respectively.

[0078] Figure 13 Shows a cross-sectional view of the said first connector 300. Figure 13 Clearly shows that the electrical contacts 100, 200 are placed within their respective through-holes 304. The through-hole 304 has a through-hole depth that is substantially equal to the thickness of the carrier 302; the through-hole 304 also has a through-hole diameter of 0.1 to 0.8 millimeters (mm). The initial length 118 is significantly longer than the through-hole depth, such that the top end 122 and the bottom end protrude from the through-hole 304, so as to physically contact the IC device 126 and the printed circuit board 128 simultaneously. On the contrary, the through-hole diameter is slightly larger than the initial diameter 116 for guiding the electrical contacts 100, 200 into the through-hole 304. Thus, once the electrical contacts 100, 200 fall into the through-hole 304, the electrical contacts 100, 200 still remain in a vertical standing posture. At the same time, when the electrical contacts 100, 200 are compressed, the through-hole 304 also restricts the lateral deformation of the electrical contacts 100, 200. Additionally, Figure 13The IC device 126 has an IC chip. Thus, the IC chip is connected to the electrical contacts 100, 200 through solder balls 148. The top layer 314 also has a plurality of top layer grooves 334 for positioning and accommodating their respective solder balls 148.

[0079] Figure 14 Shows an exploded perspective view of the second connector 350. The second connector 350 has a structure similar to that of the first connector 300, which includes electrical contacts 100, 200 and a housing or carrier 352. The carrier 352 has a plurality of through holes 354 for accommodating the electrical contacts 100, 200. The carrier 352 also has a sandwich structure substantially the same as that of the carrier 302, including a top layer 364, a bottom layer 368, and an intermediate layer 366 between the top layer 364 and the bottom layer 368. The top layer 364 has a first through hole 370 and a first hole 378; the intermediate layer 366 has a second through hole 372 and a second hole 380; the bottom layer 368 has a third through hole 374 and a third hole 382. The first through hole 370, the second through hole 372, and the third through hole 374 are aligned to form the through hole 354. The first hole 378, the second hole 380, and the third hole 382 are also aligned, so that the top layer 364, the intermediate layer 366, and the bottom layer 368 are integrally combined into the carrier 352 using carrier fasteners (such as bolts or screws).

[0080] Figure 15 Shows a cross-sectional view of the second connector 350. The second connector 350 has a structure similar to that of the first connector 300. However, Figure 15 The IC device 126 in includes an IC package having external contact pads. Thus, the IC package is directly connected to the electrical contacts 100, 200 without using solder balls 148. Therefore, the top layer 364 does not need to have a structure similar to the top layer groove 334 for the first connector 300.

[0081] Figure 16 Shows a process flow chart 400 of the electrical contact 100. The process flow chart 400 includes the following steps: a first step 410 of providing eight point wires 102 - 109; a second step 420 of intertwining or braiding the eight electrical wires 102 - 109 into an integral structure 110; a third step 430 of releasing the stress inside the integral structure 110 generated in the second step 420; a fourth step 440 of cutting the integral structure 110 into a plurality of electrical contacts 100; and a fifth step 450 of plating the plating layer 132 on the electrical contacts 100.

[0082] Figure 17A process flow diagram 500 showing the treatment of the plating layer 132 forming the electrical contact. The process flow diagram 500 includes the following steps: a first step 510 of cleaning the inner layer 130; a second step 520 of manufacturing a nickel plating layer 136 for encapsulating the inner layer 130 by a nickel electrolytic plating process until the thickness of the nickel plating layer 136 is greater than 1.0 micrometers (μm); a third step 530 of manufacturing a palladium plating layer 138 for encapsulating the nickel plating layer 136 by a palladium electrolytic plating process until the thickness of the palladium plating layer 138 is about 1.0 micrometers (μm); a fourth step 540 of manufacturing a gold plating layer 140 for encapsulating the palladium plating layer 138 by a gold electrolytic plating process until the thickness of the gold plating layer 140 is greater than 1.0 micrometers (μm); and a fifth step 550 of drying the plating layer 132 of the electrical contact 100.

[0083] In this application, the term "comprising" and its grammatical variations represent "open" or "inclusive" language, including not only the recited elements but also allowing for additional non - recited elements, unless otherwise specified.

[0084] The term "about" used herein to express the concentration of a constituent component generally means a deviation not exceeding + / - 5% of the stated value, and even + / - 4%, + / - 3%, + / - 2%, + / - 1% or + / - 0.5%.

[0085] In the present disclosure, some embodiments may be presented in a range format. The range description is merely for convenience and brevity of presentation and should not be construed as a rigid limitation on the disclosed scope. Accordingly, a range recitation encompasses all possible sub - ranges as well as the individual values within the range. For example, the range "1 - 6" should be understood to encompass sub - ranges such as 1 - 3, 1 - 4, 1 - 5, 2 - 4, 2 - 6, 3 - 6, etc., as well as the individual values within the range, such as 1, 2, 3, 4, 5, and 6. This rule applies regardless of the size of the range.

[0086] It is obvious that those skilled in the art can understand various modifications and adjustments of the application without departing from the spirit and scope of the application after reading the above disclosure, and such various modifications and adjustments shall not exceed the scope of the appended claims.

Claims

1. An electrical contact, comprising a plurality of intertwined and mutually supporting filaments; at least one of the plurality of filaments is an electrical conductor for providing a first electrical contact and a second electrical contact; characterized in that: The electrical wire has a multi-layer structure, and the multi-layer structure includes an elastic inner layer and a covering layer for encapsulating the inner layer. The inner layer is made of steel or shape memory alloy. The covering layer includes, from the inside to the outside in sequence: a copper layer, a nickel layer, a palladium layer, and a gold layer. The thickness of the copper layer is greater than 2.0 microns, the thicknesses of the nickel layer and the palladium layer are both less than 1.0 micron, and the thickness of the gold layer is greater than 1.0 micron.

2. The electrical contact according to claim 1, characterized in that: The steel is stainless steel, spring steel, or memory steel.

3. The electrical contact according to claim 1, characterized in that: At least one of the electrical wires includes a sharp edge for scraping the electrical contact surface of an external electrical device.

4. The electrical contact according to claim 1, characterized in that: The plurality of wire-like objects include at least three independent wire materials for forming an integral structure.

5. The electrical contact according to claim 4, characterized in that: The integral structure includes a tubular structure.

6. The electrical contact according to claim 5, characterized in that: In the absence of external force, at least two of the wire-like objects in the wire-like objects form an angle that is substantially a right angle.

7. The electrical contact according to claim 1, characterized in that: The multi-layer structure further includes an outer layer for encapsulating the inner layer and the covering layer.

8. The electrical contact according to claim 7, characterized in that: The outer layer includes a self-assembled monolayer (SAM) or a parylene coating.

9. A connector, characterized in that: An electrical contact according to any one of claims 1-8 and a carrier having a plurality of through holes; at least one of the electrical contacts is disposed in at least one of the through holes.

10. The connector according to claim 9, characterized in that: The carrier includes a top layer, a bottom layer, and an intermediate layer located between the top layer and the bottom layer.

11. The connector according to claim 10, characterized in that: The intermediate layer is made of a heat-conducting material.

12. A method for manufacturing an electrical contact according to any one of claims 1-8, the method comprising the following steps: Providing a plurality of wire-like objects, the plurality of wire-like objects including at least one electrical wire; Interweaving the plurality of wire-like objects to form an integral structure; and Dividing the integral structure into a plurality of the electrical contacts; Wherein at least one of the electrical wires has a first electrical contact and a second electrical contact; characterized in that at least one of the electrical wires is formed by the following steps: Providing an inner layer and forming a covering layer covering the inner layer; the inner layer is made of steel or shape memory alloy, and the covering layer includes, from the inside to the outside in sequence: a copper layer, a nickel layer, a palladium layer, and a gold layer. The thickness of the copper layer is greater than 2.0 microns, the thicknesses of the nickel layer and the palladium layer are both less than 1.0 micron, and the thickness of the gold layer is greater than 1.0 micron.

13. The method according to claim 12, wherein: The steel is stainless steel, spring steel, or memory steel.

14. The method according to claim 12, characterized in that: The method further includes forming an outer layer on the covering layer.

15. The method according to claim 14, wherein: The outer layer includes a self-assembled monolayer (SAM), and the self-assembled monolayer is less than 0.5 micron.

16. The method according to claim 14, wherein: The outer layer includes a parylene coating, and the thickness of the parylene coating is less than 0.5 micron.

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