Polysiloxane contact element
Through the combination of conductive silicone rubber and soft conductive metal, combined with the central hole structure, the problem of conflict between the flexibility and conductivity of the conductive contact part in the prior art is solved, and high frequency, high current and high density electronic components are connected. High durability and high elasticity.
Patent Information
- Application Number
- CN202010716999.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2019-07-23
- Filing Date
- 2020-07-23
- Publication Date
- 2025-01-03
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The conductive contacts in the prior art conflict between obtaining high flexibility and high conductivity, and conventional materials cannot meet the requirements of spring characteristics and temperature resistance at the same time, making it difficult to provide high frequency, high current and high in electronic component connections. Stable connection of density.
The contact elements made of conductive silicone rubber are used to coat soft conductive metals by electroless plating or electroplating, combined with the central pore structure to improve the conductivity and elastic properties, and achieve high-density connections through the design of the carrier.
It realizes high frequency, high current and high density connections between electronic components, and has high durability and high elasticity, so as to maintain good conductivity at high temperatures.
Smart Images
Figure CN112291948B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of contact elements. More specifically, the present invention relates to contact elements used for connection between electronic components (such as computer chips and printed circuit boards), or for connection between electronic components in a test socket, to provide high current, high density and high frequency connection between electronic components. Background Art
[0002] refer to Figure 1 A prior art LGA (Land Grid Array) component is used to interconnect an IC (integrated circuit) package A having a plurality of flat contact pads or solder bumps B formed on a bottom surface to contact pads C arranged in a regular pattern on a surface of a PCB (printed circuit board) D.
[0003] A prior art LGA assembly is known, which includes an insulating housing E and a plurality of elastic conductive contacts F received in channels formed in the housing E. The elastic conductive contacts F generally have exposed portions at the upper and lower surfaces of the insulating housing E for engaging flat contact pads B, C. When the IC package A is precisely positioned to overlap and align with the PCB D so that the conductive pad B engages the conductive pad C, a normal force is applied to the exposed portion of each elastic conductive contact F to electrically and mechanically engage the corresponding contact pads B, C.
[0004] The elastic conductive contact F associated with the LGA of the prior art has a variety of shapes. A common form of the elastic conductive contact includes two free ends connected by a bent elastic portion, which provides storage of elastic energy during engagement with the IC package A and the PCB D. The elastic conductive contact of the prior art can be a single metal structure in the form of a spring to provide the required elastic response during use while also serving as a conductive element for electrical connection. Alternatively, contact buttons have been developed in which a connector is wrapped, embedded or otherwise engaged with a dielectric core, which generally provides elastic energy storage during operation in which the conductor only provides a conductive path. Typically, a combination of barrier metal and precious metal plating is applied to the surface of the spring for corrosion prevention and enhanced electrical contact. Typically, these platings provide improved conductivity only along the surface of the spring.
[0005] One problem with the prior art is that the conductive contacts in the form of a single conductor spring used to achieve high compliance also have high resistance and high inductance. Furthermore, contacts in the form of multiple conductors in a bundled wiring harness, or contacts in the form of conductor structures embedded in a polymer core, are formed to have lower resistance and inductance than a single conductor spring, but require higher contact forces to deflect, and cannot achieve high compliance. Furthermore, one problem with the prior art is that good materials for constructing springs, such as high strength steel, are not very good electrical conductors. On the other hand, good electrical conductors, such as copper alloys or precious metals, generally do not provide adequate spring characteristics.
[0006] There is a need for a more resilient conductive contact that incorporates the seemingly contradictory requirements of good spring properties, temperature resistance, and high conductivity, but does not require any integral support structure.Therefore, there is a need for an improved electrical contact for use in an LGA socket or electrical connector that overcomes the disadvantages of conventional electrical contacts.
[0007] Therefore, good electrical contact elements are expected to have the following properties: (a) be usable both in production packages and in test and burn-in sockets, with the latter use requiring high durability; (b) have a large range of elastic compliance and low contact forces; (c) be capable of transmitting high-frequency signals and high currents; (d) be able to withstand high operating temperatures; (e) have a fine pitch or density; and (f) exhibit high durability, i.e., > 500 K repeated deflection. Summary of the invention
[0008] A contact element for connection between electronic components such as computer chips and printed circuit boards, or for connection between electronic components in test sockets, to provide high current, high density and high frequency connection between electronic components. When the electrical components are connected and pressed together, the contact element preferably achieves a good connection between the electrical components. The contact element is preferably made of chemically plated and / or electroplated silicone rubber. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 It is a perspective exploded view of a prior art land grid array assembly.
[0010] Figure 2 A side view of a carrier with an arrangement of contact elements is shown.
[0011] Figure 3 Shows Figure 2 A top perspective view of a carrier.
[0012] Figure 4 A cross-sectional view of an assembly of electronic components with contact elements is shown.
[0013] Figure 5 A method of producing a contact element is shown.
[0014] Figure 6 A side view of a carrier is shown, wherein the arrangement of contact elements is compressed. DETAILED DESCRIPTION
[0015] This description of the preferred embodiment is intended to be read in conjunction with the accompanying drawings, which are considered to be part of the entire written description of the invention. The drawings are not necessarily drawn to scale, and for the sake of clarity and conciseness, certain features of the invention may be shown in an enlarged scale or in some schematic form. In the description, related terms such as "horizontal", "vertical", "upward", "downward", "top" and "bottom" and their derivatives (e.g., "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the orientation shown in the drawings described or discussed at the time. These related terms are for convenience of description and are generally not intended to require a specific orientation. Terms including "inward" versus "outward", "longitudinal" versus "lateral", etc. should be interpreted relative to each other or relative to an elongation axis or an axis of rotation or a center of rotation as appropriate. Terms such as "connect" and "interconnect" regarding attachment, connection, etc. refer to a relationship in which structures are fixed or attached to each other directly or indirectly through intermediate structures, as well as removable or rigid attachments or relationships, unless otherwise explicitly described. The term "operably connected" is such an attachment, connection or connection that allows the related structures to operate as expected by virtue of the relationship. In the claims, means-plus-function clauses are intended to cover the structures for performing the recited function as described, suggested, or apparent from the written description or drawings, including not only structural equivalents but also equivalent structures.
[0016] refer to Figures 2 to 4 and Figure 6 The contact element 2 of the embodiment of the present invention is present between electronic components, such as between a computer chip (IC package A) and a printed circuit board (PCB) D, or in the connection between electronic components in a test socket to provide high current, high density and high frequency connection between electronic components. The contact element 2 of the embodiment of the present invention is preferably an electrical contact portion. The term "electrical contact portion" can be used interchangeably with the terms "electrical contact element" and "contact element" in this article. The conductive contact element 2 preferably achieves a good connection between the electrical components when they are connected and pressed together.
[0017] The contact element 2 of the present invention is an alternative to metal springs and metal connectors between electronic components A, D. The contact element 2 preferably allows the electronic components A, D to be connected and disconnected multiple times and the contact element 2 retains its spring-like capabilities in addition to its conductive properties.
[0018] The contact element 2 of the present embodiment preferably includes spring-like characteristics such as elasticity, and acts as an elastic object that stores mechanical energy, and can be compressed or stretched from a static position to exert an opposing force approximately proportional to the change in its length.
[0019] The contact element 2 is preferably made of conductive silicone rubber. The conductive silicone rubber can be a flexible conductive moisture-cured RTV (room temperature vulcanized) polysilicone. For example, conductive silicone rubber SS-26S from Silicon Solutions of Cuyahoga Falls, OH. The conductive polysilicone can be dispensed manually or automatically by a dispensing device and has a thixotropic consistency. The conductive silicone rubber preferably has a conductivity of at least 0.005 ohm-cm (5×10 -3 Ohm / cm) volume resistivity.
[0020] The contact element 2 has a first end 2a, a second end 2b and a total length L with an outer circumference 2c. A central hole 3 is preferably present in the contact element 2. The central hole 3 preferably extends from the first end 2a to the second end 2b. In other embodiments, the length of the central hole 3 extending from the first end 2a toward the second end 2b is shorter than the total length L.
[0021] The silicone rubber of the contact element 2 is preferably plated with 4 a soft conductive metal. Plating can be performed via electroplating, electroless (chemical) plating or a combination of electroless (chemical) plating and then electroplating. The conductive metal can include, but is not limited to, copper, gold, silver or platinum. When the electronic component parts A, D are joined together and the polysiloxane contact element 2 is compressed between the components A, D, a thin layer of plating 4 on the contact element 2 allows the plating 4 to flex along with the polysiloxane contact element while providing improved conductivity, such as Figure 6 as shown in .
[0022] The central hole 3 in the contact element 2 allows for plating 4 of the entire element 2 so that there is additional conductivity from the first end 2a to the second end 2b and through the middle of the polysiloxane contact element 2 to allow for better electrical connection across the outer circumference 2c of the contact element 2.
[0023] In a specific arrangement, the contact element 2 is received on or in a carrier 7 referred to as an enclosure E. A specific arrangement is a pattern corresponding to a specific component pinhole configuration that is necessary to fully support the electrical component and ensure sufficient electrical connection. Although the carrier 7 is generally shown in the accompanying drawings, the carrier can have any shape. The carrier 7 is usually made of plastic or similar non-conductive materials. A specific arrangement can include a high-density, narrow-pitch pin arrangement.
[0024] Electronic components can be Figure 5 The method shown makes electronic connections. Optionally, a thin layer of wax, plastic sheet or other material 9 can be added to the carrier (step 100). In one embodiment, this thin layer is removed at the end of the manufacturing process before the contact elements 2 are compressed with additional electronic components, so that the contact elements protrude from the carrier 7, ensuring that the contact elements retain their shape and the desired pattern.
[0025] Then, the carrier 7 is drilled with a specific component pin hole structure 8 (step 102). The construction material for the carrier 7 starts from a substrate, which includes but is not limited to epoxy / glass composites, sheets or films such as Kaepton (Kapton), filled polymers, photosensitive polymers, semiconductor wafers and others. Epoxy / glass composites are glass fiber reinforced epoxy substrates for PCBs. The hole 8 can be produced by drilling, laser drilling or selective photoetching processes. Generally, the position of the hole 8 is more accurately located when it is produced by a photoetching process than by mechanical drilling or laser drilling. Photosensitive polymers are useful in cases where it is desired to maintain high accuracy in the position of the hole 8, and are obtained by the following operations: masking selected portions of the photoexposed polymer, then light exposing the unmasked portions of the photosensitive polymer to light develop it, then washing away the undeveloped photosensitive polymer, leaving a patterned mask (masking), and then etching the lower layer of the substrate exposed by the patterned mask.
[0026] Next, the pin hole 8 is filled with conductive silicone rubber that forms the contact element 2 (step 104). The polysiloxane is used as a glue, so that instead of gluing or attaching the contact element 2 in the carrier 7, the polysiloxane is injected into the pin hole 8 in the carrier 7, and the polysiloxane itself becomes the adhesive and the contact element 2 in one. This improves the surface area and volume of the contact element 2, making it far greater than that of a spring or a plurality of wires comprising a prior art contact element. Due to the increased volume compared to conventional wires / springs, the resistance is much lower, thereby providing a contact element 2 that can support the higher frequency needs of electronic components A, D.
[0027] After the conductive silicone rubber of the contact element 2 has dried (step 106), a central hole 3 is drilled or punched (step 108). The hole 3 preferably has a smaller diameter than the diameter of the pin hole 8 structure so that a hollow or partially hollow cylinder of conductive polysiloxane is maintained. The hole 3 allows the entire contact element 2 to be plated so that there is additional conductivity from each side of the contact element 2 and through the middle of the contact element 2 to allow for better electrical connection across the outer diameter 2d of the contact element 2. The diameter of the hole 3 can be a variety of sizes and can be drilled with a laser cutter or other drilling equipment. Because the hole size can vary, the number of pins and the specific configuration of the pins can be customized according to the application.
[0028] Next, the polysiloxane contact element 2 is plated. The plating can be electroplating only, electroless plating only (chemical plating), or a combination of electroplating and electroless plating to increase adhesion (step 110). Plating of the contact element 2 increases the conductivity of the polysiloxane and reduces the force required to make a suitable electronic connection between the electronic components A, D compared to using only conductive polysiloxane. The plating is performed using soft metals such as, but not limited to, copper, tin, gold, and platinum. The plating of the polysiloxane contact element 2 preferably results in a volume resistivity in the range of between 0.005-0.0000172 ohms / cm.
[0029] At this point in the process, if a thin layer of masking material 9 is applied, it is removed (step 112). The masking material can be a wax or plastic masking sheet. It should be noted that in this embodiment, the first end 2a of the contact element 2, the outer circumference 2c of the contact element 2 and the central hole 3 are plated.
[0030] It should be noted that in an alternative embodiment, a thin layer of masking material is removed prior to electroplating. In this embodiment, the entire contact element 2 of the first end 2a, the second end 2b, the outer circumference 2c and the central hole 3 is plated. Therefore, the step 112 of removing the wax layer is moved to after the step 108 of drilling the hole in the contact element 2.
[0031] In a preferred embodiment, the masking material is not removed until after electroless plating is complete.
[0032] In one embodiment, the polysiloxane contact element is copper plated because copper provides low resistance and anneals at relatively low temperatures. In this embodiment, the copper plated polysiloxane contact element has a resistance of approximately 0.00000172 ohms / cm (1.72×10 -6 Ohm / cm) volume resistivity.
[0033] Optionally, the plated contact element 2 is annealed (step 114). The annealing process hardens the plated material and helps ensure that the contact element 2 returns to its original or resting shape after being compressed.
[0034] It should be noted that, as the conductivity increases, the portion of the contact member 2 that protrudes from the carrier 7 does not need to be very large to form a connection.
[0035] After the contact elements 2 have been plated 4 , the electronic component A is applied with force to the carrier 7 and the contact elements 2 to provide electronic connectivity (step 116 ), and the method ends.
[0036] When completed, the result will be a carrier 7 having metallized silicone spring contact elements 2 designed to the specifications required by the application. These silicone contact elements 2 are attached to the carrier 7 and do not require any type of special adhesive to hold them in place.
[0037] The carrier 7 defines the contact pattern of the electronic package. The polysiloxane contact element 2 provides the necessary force / compliance to achieve a good connection between the different parts, in addition to providing electrical contact between the components A, D. The metallization increases the contact resistance beyond the electrical properties of the conductive polysiloxane.
[0038] Therefore, it should be understood that the embodiments of the invention described herein are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features considered essential to the invention.
Claims
1. A method of connecting electronic components for electronic connectivity, comprising: drilling a pin hole structure having at least one pin hole in the carrier attached to the first electronic component; filling each of the at least one pin hole with a contact element of conductive silicone rubber so that a first end of the contact element contacts the first electronic component; drying the contact element of the conductive silicone rubber; drilling a central hole in each of the conductive silicone rubber contact elements; Plating the contact element; as well as A second electronic component is applied with force to a second end of the contact element opposite the first end such that electrical connectivity is established between the first electronic component and the second electronic component.
2. The method according to claim 1, further comprising: A thin layer of mask is added to the carrier before drilling the pin hole structure into the carrier.
3. The method according to claim 2, further comprising: The thin-layer mask is removed after the contact elements have been plated.
4. The method according to claim 2, further comprising: The thin layer mask is removed before the contact elements are plated.
5. The method according to claim 3, wherein: The plating is electroplating.
6. The method according to claim 4, wherein: The plating is electroplating.
7. The method according to claim 1, wherein: The plating is selected from the group consisting of: electroplating only, electroless plating and electroplating, and electroless plating only.
8. The method according to claim 1, wherein: The central bore extends from the first end of the contact element to the second end of the contact element.
9. The method according to claim 1, wherein: The central hole extends part way along the length of the contact element.
10. The method according to claim 1, wherein: The plating deposits a soft conductive metal on the outer circumference of the contact element, the first end, the second end, and the central hole.
11. The method according to claim 10, wherein: The soft conductive metal is selected from the group consisting of copper, tin, gold and platinum.
12. The method according to claim 1, wherein: The conductive silicone rubber is a flexible, electronically conductive, moisture-curable, room temperature vulcanizing silicone rubber.
13. The method according to claim 1, wherein: At least one of the first electronic component or the second electronic component is removable.
14. The method according to claim 1, wherein: No adhesive is required between the first electronic component, the contact element and the second electronic component.
15. The method according to claim 1, wherein: The contact element is attached to the carrier.
16. A contact element for electrically connecting a first electronic component to a second electronic component, comprising: An elastic body of conductive silicone rubber, wherein the elastic body of conductive silicone rubber comprises: First end; a second end, the second end being opposite the first end and separated by a length; outer circumference; a central hole extending from the first end toward the second end; as well as A plating layer covers the first end, the second end, the outer circumference and the central hole in a soft conductive metal layer.
17. The contact element according to claim 16, wherein: The contact element has a volume resistivity of at least 0.005-0.00000172 ohm / cm.
18. The contact element according to claim 16, wherein: The soft conductive metal layer is selected from the group consisting of copper, tin, gold and platinum.