Connection body and method for manufacturing connection body

Abstract

To provide a connection body which can be fine-pitched and miniaturized, and to provide a method of manufacturing the connection body.SOLUTION: A connection body includes a substrate (10) having a first row of terminals (11), a connector (20) having second rows of terminals (21A to 21E), and an adhesive layer (30) formed by curing a heat-curable connecting material that connects the first row of terminals (11) and the second row of terminals (21), wherein the second rows of terminals (21A to 21E) are disposed on a bottom surface of the connector (20) and form a step absorbing portion that absorbs a step on the bottom surface, and the heat-curable connecting material contains solder particles and flux components. As a result, the first row of terminals 11 and the second rows of terminals 21A to 21E can be connected to each other, so that the rows of terminals can be fine-pitched, and the connection body can be downsized.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present technology relates to a connection body that mounts a connector, and a method for manufacturing the connection body. [Background technology]

[0002] Conventionally, connectors have been mounted by applying solder paste to a substrate or by applying solder (BGA) to the conductor portion of the connector and then solder mounting by reflow (see, for example, Patent Document 1). In recent years, with the demand for miniaturization of electronic devices, connector pitches of 0.8 mm or less, and even 0.3 mm or less, are desired.

[0003] Anisotropic connection is one technique for connecting rows of terminals with a narrow pitch. However, because connectors are generally made of molded resin, there is a concern that if anisotropic connection is used, the connector may be deformed by the pressure applied by the tool during the actual crimping process, making it impossible to insert a cable, for example.

[0004] Furthermore, in conventional connectors, solder resist is used for the terminal rows on the board side when soldering, making it difficult to further narrow the pitch of the connector's terminal rows. Also, in conventional connectors, the lead terminals (gull-wing terminals) extend outward, which increases the mounting area and hinders miniaturization of the mounted body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-284199 Summary of the Invention [Problem to be solved by the invention]

[0006] The present technology has been proposed in view of the above-described conventional situation, and provides a connector that can be made finer-pitch and smaller, and a method for manufacturing the connector. [Means for solving the problem]

[0007] The connecting body according to the present technology comprises a substrate having a first terminal row, a connector having a second terminal row, and an adhesive layer formed by hardening a thermosetting connecting material that connects the first terminal row and the second terminal row, the second terminal row being disposed on the bottom surface of the connector and forming a step absorbing portion that absorbs steps on the bottom surface, and the thermosetting connecting material containing solder particles and a flux component.

[0008] The method for manufacturing a connector according to the present technology involves placing a connector on a substrate having a first terminal row, with a second terminal row arranged on its bottom surface via a thermosetting connecting material containing solder particles and a flux component, and with a step absorbing portion formed to absorb steps on the bottom surface, and then thermally curing the thermosetting connecting material at a temperature equal to or higher than the melting point of the solder particles without pressing the connector, thereby connecting the first terminal row and the second terminal row. [Effects of the Invention]

[0009] According to this technology, by arranging the terminal row on the bottom surface of the connector and absorbing the step on the bottom surface, the terminal row can be arranged at a fine pitch, and the connecting body can be made smaller. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a connector according to the present embodiment. [Figure 2] FIG. 2 is a top view showing an example of a plug according to the prior art. [Figure 3] FIG. 3 is a top view showing an example of a receptacle according to the prior art. [Figure 4] 4 is a cross-sectional view taken along line AA of the plug shown in FIG. 2 and the receptacle shown in FIG. [Figure 5] FIG. 5 is a top view showing an example of a plug according to this embodiment. [Figure 6] FIG. 6 is a top view showing an example of a receptacle according to the present embodiment. [Figure 7] 7 is a cross-sectional view of the plug shown in FIG. 5 and the receptacle shown in FIG. 6 taken along line AA. [Figure 8] FIG. 8 is a cross-sectional view schematically showing an example of the substrate. [Figure 9] FIG. 9 is a cross-sectional view that schematically shows a state in which a thermosetting connecting material is provided on a terminal of a substrate. [Figure 10] FIG. 10 is a cross-sectional view that schematically shows the alignment between the terminal rows of the board and the terminal rows of the connector. [Figure 11] FIG. 11 is a cross-sectional view schematically showing a state in which the connector is mounted on the board. [Figure 12] FIG. 12 is a cross-sectional view that schematically shows the state in which the substrate and the connector are heated in a reflow furnace. [Figure 13] FIG. 13 is a perspective view showing the connector structure used in the simulation. [Figure 14] FIG. 14 is a cross-sectional view showing an example of a connector structure used in the simulation. [Figure 15] FIG. 15(A) is a cross-sectional view showing a first configuration example (Plug-1) of the plug, and FIG. 15(B) is a cross-sectional view showing a second configuration example (Plug-2) of the plug. [Figure 16] FIG. 16(A) is a cross-sectional view showing a third configuration example (Plug-3) of the plug, and FIG. 16(B) is a cross-sectional view showing a fourth configuration example (Plug-4) of the plug. [Figure 17] FIG. 17(A) is a cross-sectional view showing a first L configuration example of the plug (Plug-1 Loop), and FIG. 17(B) is a cross-sectional view showing a second L configuration example of the plug (Plug-2 Loop). [Figure 18] FIG. 18(A) is a cross-sectional view showing a third L configuration example of the plug (Plug-3 Loop), and FIG. 18(B) is a cross-sectional view showing a fourth L configuration example of the plug (Plug-4 Loop). [Figure 19] FIG. 19 is a cross-sectional view showing a first configuration example of a receptacle (Receptacle-0). [Figure 20]FIG. 20 is a cross-sectional view showing a second configuration example of the receptacle (Receptacle-1). [Figure 21] FIG. 21 is a cross-sectional view showing a third configuration example of the receptacle (Receptacle-2). [Figure 22] FIG. 22 is a cross-sectional view showing a fourth configuration example of the receptacle (Receptacle-3). [Figure 23] FIG. 23 is a graph showing a transmission signal S21 when the plug of the first configuration example (Plug-1) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 24] FIG. 24 is a graph showing a reflected signal S11 when the plug of the first configuration example (Plug-1) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 25] FIG. 25 is a graph showing a transmission signal S21 when the plug of the second configuration example (Plug-2) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 26] FIG. 26 is a graph showing a reflected signal S11 when the plug of the second configuration example (Plug-2) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 27] FIG. 27 is a graph showing a transmission signal S21 when the plug of the third configuration example (Plug-3) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 28] FIG. 28 is a graph showing a reflected signal S11 when the plug of the third configuration example (Plug-3) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 29]FIG. 29 is a graph showing a transmission signal S21 when the plug of the fourth configuration example (Plug-4) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 30] FIG. 30 is a graph showing a reflected signal S11 when the plug of the fourth configuration example (Plug-4) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 31] FIG. 31 is a graph showing a transmission signal S21 when the plug of the first configuration example (Plug-1 Loop) and the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3) are connected. [Figure 32] FIG. 32 is a graph showing a reflected signal S11 when the plug of the first configuration example (Plug-1 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 33] FIG. 33 is a graph showing a transmission signal S21 when the plug of the second configuration example (Plug-2 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 34] FIG. 34 is a graph showing a reflected signal S11 when the plug of the second configuration example (Plug-2 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 35] FIG. 35 is a graph showing a transmission signal S21 when the plug of the third configuration example (Plug-3 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 36] FIG. 36 is a graph showing a reflected signal S11 when the plug of the third configuration example (Plug-3 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). [Figure 37]FIG. 37 is a graph showing a transmission signal S21 when the plug of the fourth configuration example (Plug-4 Loop) and the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3) are connected. [Figure 38] FIG. 38 is a graph showing a reflected signal S11 when the plug of the fourth configuration example (Plug-4 Loop) is connected to the receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3). DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present technology will be described in detail in the following order with reference to the drawings. 1. Connector 2. Thermosetting connecting materials 3. Manufacturing method of connector 4. Connector 5. Working Example

[0012] <1. Connector> The connector according to this embodiment includes a substrate having a first terminal row, a connector having a second terminal row, and an adhesive layer formed by hardening a thermosetting connecting material that connects the first terminal row and the second terminal row, the second terminal row being disposed on the bottom surface of the connector and forming a step absorbing portion that absorbs steps on the bottom surface, the thermosetting connecting material containing solder particles and a flux component, which can absorb steps on the bottom surface, thereby enabling the terminal rows to be arranged at a finer pitch and the connector to be made smaller.

[0013] By miniaturizing the connector, it is possible to reduce the weight and size of electronic devices. It also makes it possible to miniaturize the mounting boards inside electronic devices such as smartphones and personal computers. It also makes it possible to increase the capacity of batteries. It also makes it possible to expand functionality by increasing the size of various electronic components, such as larger fingerprint sensors.

[0014] Furthermore, if the bottom surface of the connector has a step of a predetermined height range, it is preferable that the difference between the maximum and minimum heights of the terminal surfaces in the second terminal row is smaller than the predetermined height range, thereby absorbing the step of the bottom surface of the connector and enabling connection between the first terminal row and the second terminal row.

[0015] Furthermore, it is preferable that the difference between the maximum and minimum heights of the terminal surfaces in the second terminal row is smaller than the average particle diameter of the solder particles, which allows for an even finer pitch in the terminal row and an even smaller connector.

[0016] Here, a connector is a molded product, mainly made of resin, with a mating portion. Examples of connectors include plug and receptacle board-to-board connectors, board-to-flexible printed circuits (FPCs), and surface-mount devices (SMDs) such as FPC connectors that fit FPCs using a flip-lock system. A connector is an electrical connection between two materials or components.

[0017] Fig. 1 is a cross-sectional view schematically showing an example of a connection body according to the present embodiment. As shown in Fig. 1, the connection body includes a substrate 10 having a first terminal row 11, a connector 20 having second terminal rows 21A to 21E, and an adhesive layer 30 formed by hardening a thermosetting connecting material that connects the first terminal row 11 and the second terminal row 21.

[0018] The substrate 10 has a first terminal row 11 corresponding to the second terminal rows 21A to 21E of the connector 20. The substrate 10 is not particularly limited, and may be a substrate that can be broadly defined as a so-called printed wiring board (PWB), and may be either a rigid substrate or a flexible substrate. Examples of substrates based on the type of base material include a glass substrate, a ceramic substrate, and a plastic substrate.

[0019] Furthermore, it is preferable that no solder resist processing (walls, grooves, etc.) for preventing short circuits is formed between adjacent terminals (spaces) in the first terminal row 11. The height of the terminal surfaces of the first terminal row 11 may be the same as the board surface (the terminals do not protrude and the connection surface is flat) or may protrude from the board surface as shown in Fig. 1. This allows the first terminal row 11 and the second terminal rows 21A to 21E to be connected by solder particles, and the terminal rows can be arranged at a fine pitch.

[0020] Connector 20 has a step absorbing portion consisting of second terminal rows 21A to 21E on the surface that contacts the thermosetting connecting material. Because connector 20 is a resin molded product, the bottom surface of connector 20 usually has a step (waviness) with a height of about 20 μm that is formed by resin molding during production.

[0021] The step absorbing portion aligns the height of the terminal surfaces of the second terminal rows 21A to 21E and absorbs steps on the bottom surface of the connector 20. The difference between the maximum and minimum heights of the terminal surfaces of the second terminal rows 21A to 21E is preferably smaller than the steps on the bottom surface of the connector 20 and the average particle diameter of the solder particles, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0022] Here, the average particle size refers to the average major axis diameter of particles measured, for example, at N=20 or more, preferably N=50 or more, and more preferably N=200 or more, in observation images using a metallurgical microscope, optical microscope, or electron microscope such as a scanning electron microscope (SEM). In the case of spherical particles, it refers to the average diameter of the particles. Also, the observed images may be measured using known image analysis software (such as "WinROOF" from Mitani Corporation or "Azokun (registered trademark)" from Asahi Kasei Engineering Corporation) or may be measured (N=1000 or more) using an imaging particle size analyzer (e.g., FPIA-3000 from Malvern Instruments). The average particle size determined from the observed images or imaging particle size analyzer can be the average maximum length of the particles. When preparing a thermosetting connecting material, manufacturer values ​​such as the particle size (D50) at which the cumulative frequency in the particle size distribution determined by laser diffraction / scattering is 50% or greater, or the arithmetic mean diameter (preferably on a volume basis) can be used.

[0023] As shown in FIG. 1, the step absorbing portion may be formed, for example, in a manner such that a terminal is formed inside the resin mold, such as second terminals 21A and 21E, in a manner such that a terminal is formed on the surface of the resin mold, such as second terminals 21B and 21D, or in a manner such that a terminal is formed away from the surface of the resin mold, such as second terminal 21C. The step absorbing portion can be formed, for example, by bending a lead terminal extending toward the outside of the connector to the bottom surface of the connector and aligning the height of the terminal surface. Alternatively, the step absorbing portion can be formed, for example, by forming a terminal so that it is positioned on the bottom surface in advance and then molding it with resin. If necessary, the terminal surface may be polished to align the height of the terminal surface.

[0024] As will be described later, the adhesive layer 30 is a film-like material formed by hardening a thermosetting connecting material containing solder particles 31 and a flux component. The adhesive layer 30 solder-joins 32 the first terminal row 11 of the substrate 10 and the second terminal row 21 of the connector 20, and also bonds the substrate 10 and the connector together with the thermosetting binder of the thermosetting connecting material. One terminal surface will have multiple solder joints 32 and bonding areas formed with the thermosetting binder.

[0025] In the connector according to this embodiment, the upper limit of the minimum value of the distance between adjacent terminals (space distance) in the first terminal row 11 and the second terminal row 21 is 800 μm or less, preferably 300 μm or less, and more preferably 150 μm or less. The lower limit of the minimum value of the distance between adjacent terminals in the first terminal row 11 and the second terminal row 21 is 30 μm or more, more preferably 50 μm or more, and even more preferably 70 μm or more.

[0026] The upper limit of the ratio of the average particle diameter of the solder particles 31 to the minimum distance between adjacent terminals in the first terminal row 11 and the second terminal row 21 is less than 0.15, and more preferably 0.1 or less. The minimum value of the sum of the terminal height (distance) between the terminal surface of the first terminal row 11 and the board surface and the terminal height (distance) between the terminal surface of the second terminal row 21 and the connector bottom surface is preferably larger than the average particle diameter of the solder particles 31.

[0027] Furthermore, the surfaces of the terminals in the first terminal row 11 and the second terminal row 21 may be gold-plated. Furthermore, it is desirable that the substrate 10 and the connector 20 have heat resistance during reflow.

[0028] According to the connection body of this embodiment, the step absorbing portion consisting of the second terminal rows 21A to 21E on the bottom surface of the connector 20 can absorb the steps on the bottom surface and can make connections using solder particles, so it is possible to accommodate finer pitch terminal rows and make the connector smaller.

[0029] The connector of this embodiment is connected using solder particles that are widely used in solder paste and BGA (Ball Grid Array), and has high connection reliability, so it can be used in a wide range of applications, such as sensor devices, discrete components, various IC chips, modules, eSim (Embedded Subscriber Identity Module), SoC (System on a chip), automotive devices, and IoT (Internet of Things) devices.

[0030] Figures 2 to 4 are diagrams showing an example of a board-to-board connector including a plug and a receptacle according to the prior art, where Figure 2 is a top view showing an example of a plug according to the prior art, Figure 3 is a top view showing an example of a receptacle according to the prior art, and Figure 4 is a cross-sectional view taken along line AA of the plug shown in Figure 2 and the receptacle shown in Figure 3.

[0031] A plug 140 according to the prior art includes a first male vertical mating row 141A, a second male vertical mating row 141B, a first lead terminal row 142A extending from the first male vertical mating row 141A to the bottom surface and extending outward in the short direction, a second lead terminal row 142B extending from the second male vertical mating row 142A to the bottom surface and extending outward in the short direction, and insulating resin 143 that secures these. The plug 140 according to the prior art also includes a first reinforcing portion 144A provided at one end in the longitudinal direction and a second reinforcing portion 144B provided at the other end in the longitudinal direction. Because the adhesive strength between the first lead terminal row 142A and the second lead terminal row 142B is insufficient when soldered alone, reinforcing metal fittings are sometimes formed on the bottom surfaces of the first reinforcing portion 144A and the second reinforcing portion 144B.

[0032] Furthermore, receptacle 150 according to the prior art includes first female vertical mating row 151A, second female vertical mating row 151B, first lead terminal row 152A extending from first female vertical mating row 151A to the bottom surface and extending outward in the short direction, second lead terminal row 152B extending from second female vertical mating row 152A to the bottom surface and extending outward in the short direction, and insulating resin 153 that secures these. Furthermore, receptacle 150 according to the prior art includes first reinforcing portion 154A provided at one end in the longitudinal direction and second reinforcing portion 154B provided at the other end in the longitudinal direction. Since the adhesive strength is insufficient when only soldering the first lead terminal row 152A and the second lead terminal row 152B, similar to the plug 140, reinforcing metal fittings may be formed on the bottom surfaces of the first reinforcing portion 154A and the second reinforcing portion 154B.

[0033] The plug 140 and receptacle 150 according to the prior art are so-called centipede-type connectors in which the lead terminal rows extend outward, which requires a relatively large mounting area, and reinforcement sections due to insufficient adhesion further hinder miniaturization. Also, if there is a step of a certain height range on the bottom surface of the connector, in order to connect with solder particles, the average particle diameter of the solder particles must be larger than the height of the step of a certain height range, which hinders the terminal row from being fine-pitched.

[0034] Figures 5 to 7 are diagrams showing an example of a board-to-board connector including a plug and a receptacle according to this embodiment, where Figure 5 is a top view showing an example of a plug according to this embodiment, Figure 6 is a top view showing an example of a receptacle according to this embodiment, and Figure 7 is a cross-sectional view taken along line AA of the plug shown in Figure 5 and the receptacle shown in Figure 6.

[0035] The plug 40 according to this embodiment comprises a first male vertical mating row 41A, a second male vertical mating row 41B, a first terminal row 42A extending from the first male vertical mating row 41A to the bottom surface and extending inward in the short direction, a second terminal row 42B extending from the second male vertical mating row 41B to the bottom surface and extending inward in the short direction, and insulating resin 43 for fixing these together, and the first terminal row 42A and the second terminal row 42B protrude from the bottom surface to form a step absorbing portion that makes the height of the terminal surfaces the same.

[0036] Furthermore, receptacle 50 according to this embodiment includes first female-type vertical mating row 51A, second female-type vertical mating row 51B, first terminal row 52A extending from first female-type vertical mating row 51A to the bottom surface and extending inward in the short direction, second terminal row 52B extending from second female-type vertical mating row 51B to the bottom surface and extending inward in the short direction, and insulating resin 53 that secures these together, and first terminal row 52A and second terminal row 52B protrude from the bottom surface to form a step absorbing portion with little variation in the height of the terminal surface.

[0037] The first male vertical mating row 41A of the plug 40 and the first female vertical mating row 51A of the receptacle 50 are formed in metal shapes to allow for vertical mating, and the second male vertical mating row 41B of the plug 40 and the second female vertical mating row 51B of the receptacle 50 are formed in metal shapes to allow for vertical mating.

[0038] Insulating resins 43, 53 are made of, for example, polyamide or LCP, and fix first terminal row 42A and second terminal row 42B of plug 40 and first terminal row 52A and second terminal row 52B of receptacle 50 by, for example, resin molding.

[0039] That is, the plug and receptacle according to the present embodiment have terminal rows extending inward from the outside of the bottom surface of the connector, whereas the plug and receptacle according to the prior art have terminal rows extending outward from the bottom surface of the connector.Furthermore, the plug and receptacle according to the present embodiment do not need to have a reinforcing portion, whereas the plug and receptacle according to the prior art always have a reinforcing portion.

[0040] According to the plug and receptacle of this embodiment, by arranging the terminal row on the bottom surface, it is possible to reduce the mounting area compared to the so-called centipede-type connector of the prior art. Furthermore, since the step on the bottom surface of the connector can be absorbed, the terminal row can be fine-pitched, and the connector can be made smaller. Furthermore, because the bottom surface of the connector is bonded with a thermosetting connecting material, it is possible to configure it without a reinforcing portion formed with a reinforcing metal fitting, and the connector can be made even smaller.

[0041] <2. Thermosetting connecting materials> The thermosetting connecting material according to this embodiment contains solder particles and a flux component. The flux component removes oxide films from the solder particles and terminal surfaces and reduces the surface tension of the molten solder, allowing connections to be made by no-load reflow without thermocompression bonding using a tool. Here, no-load refers to a state in which no mechanical pressure is applied during reflow.

[0042] The thermosetting connecting material may be either a film-like thermosetting connecting film or a paste-like thermosetting connecting paste. The thermosetting connecting paste may be in the form of a film when connecting, or may be in the form of a film by mounting components.

[0043] In the case of a thermosetting connecting paste, it is sufficient to apply a predetermined amount uniformly onto a substrate, and application methods such as dispensing, stamping, screen printing, etc. can be used, and drying may be performed as necessary. In this case, it is expected that capital investment can be reduced by reusing or modifying conventional solder paste equipment.

[0044] Thermosetting connecting films are particularly preferred because they can not only uniformize the amount of bonding material (e.g., anisotropic conductive material) depending on the film thickness, but also enable simultaneous lamination onto the substrate, shortening the takt time. Furthermore, by forming them into a film in advance, they are easier to handle, which is expected to improve work efficiency.

[0045] Furthermore, thermosetting connection films can be laminated onto substrates in one go, making it possible to mount not only connectors but also various electronic components such as discrete components, various IC chips, modules, eSIMs, and SoCs all at once, thereby shortening takt time and achieving finer pitches for various electronic components. Furthermore, achieving finer pitches for various electronic components makes it possible to reduce the distance between adjacent mounted components, enabling higher-density mounting. By achieving finer pitches for various electronic components, the components become smaller, which, for example, leads to more components being cut from a single wafer, thereby reducing costs. Furthermore, not only for wafers, but also for various electronic components, the smaller components can reduce costs.

[0046] Furthermore, connections using thermosetting connecting materials are not limited to the above-mentioned components, but can be applied to all SMT components that have conductive connecting terminals and whose height is flat or convex relative to the bottom surface. Furthermore, various electronic components fixed with thermosetting connecting materials and various electronic components fixed with connecting materials such as solder paste can be simultaneously introduced into a reflow soldering process and connected.

[0047] The minimum melt viscosity of the thermosetting connecting material may be less than 100 Pa·s, preferably 50 Pa·s or less, more preferably 30 Pa·s or less, and even more preferably 10 Pa·s or less. If the minimum melt viscosity is too high, resin melting will not proceed without load during reflow, which may cause problems with clamping between the solder particles and the terminals. Furthermore, the minimum melt viscosity temperature of the thermosetting connecting material is preferably −10°C to −60°C below the melting point of the solder particles, more preferably −10°C to −50°C below the melting point of the solder particles, and even more preferably −10°C to −40°C below the melting point of the solder particles. This allows the minimum melt viscosity to be reached before the solder melts, melting the resin, and then melting the solder particles after the resin melts, and then the resin can be hardened, resulting in a good solder joint. Here, the minimum melt viscosity temperature of a thermosetting connecting material refers to the temperature at which the viscosity reaches its minimum value (minimum melt viscosity) when measured using, for example, a rotational rheometer (manufactured by TA Instrument) under the following conditions: measurement pressure 5 g, temperature range 30 to 200°C, heating rate 10°C / min, measurement frequency 10 Hz, measurement plate diameter 8 mm, and load fluctuation on the measurement plate 5 g.

[0048] Furthermore, the thermosetting connecting material preferably has a peak exothermic temperature higher than the melting point of the solder particles, but a melting temperature lower than the melting point of the solder particles. This allows the solder to melt while the solder particles are sandwiched between the terminals after the thermosetting binder melts, enabling fine-pitch terminal rows to be joined. The peak exothermic temperature can be measured by differential scanning calorimetry (DSC) using a sample of 5 mg or more weighed in an aluminum pan at a temperature range of 30 to 250°C and a heating rate of 10°C / min.

[0049] When the thermosetting connecting material is in film form, the lower limit of the ratio of the average particle diameter of the solder particles to the thickness of the thermosetting connecting material is preferably 0.5 or more, more preferably 0.6 or more. This facilitates sandwiching of the solder particles between the terminals and allows for fine-pitch terminal rows. Here, the film thickness can be measured using a known micrometer or digital thickness gauge (e.g., Mitutoyo Corporation: MDE-25M, minimum display: 0.0001 mm) capable of measuring 1 μm or less, preferably 0.1 μm or less. The film thickness can be determined by averaging measurements taken at 10 or more locations. However, when the film thickness is thinner than the particle diameter, a contact-type thickness gauge is not suitable, and therefore a laser displacement meter (e.g., Keyence Corporation, spectral interference displacement type SI-T series, etc.) is preferably used. The film thickness refers to the thickness of the resin layer only and does not include the particle diameter. The average particle diameter can be determined by measuring the thickness of the film at a thickness of 1 mm in plan view using a known metallurgical microscope or optical microscope. 2 The above areas can be checked by randomly selecting five or more locations.

[0050] [Solder particles] The solder particles may or may not be those specified in JIS Z 3282-1999, and can be appropriately selected from, for example, Sn-Pb, Pb-Sn-Sb, Sn-Sb, Sn-Pb-Bi, Bi-Sn, Sn-Bi-Cu, Sn-Cu, Sn-Pb-Cu, Sn-In, Sn-Ag, Sn-Pb-Ag, Pb-Ag, etc., depending on the terminal material, connection conditions, etc.

[0051] The lower limit of the melting point of the solder particles is preferably 110°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher. The upper limit of the melting point of the solder particles may be 200°C or lower, preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. Furthermore, a flux compound may be directly bonded to the surface of the solder particles for the purpose of surface activation. Activating the surface can promote metal bonding with the terminal.

[0052] The average particle diameter of the solder particles is preferably 0.2 times or less the minimum inter-terminal distance (space distance) between the first terminal row of the substrate and the second terminal row of the connector. If the average particle diameter of the solder particles is greater than 0.2 times the minimum inter-terminal distance between the first terminal row of the substrate and the second terminal row of the connector, the possibility of a short circuit occurring increases.

[0053] The lower limit of the average particle size of the solder particles is preferably 0.5 μm or more, more preferably 3 μm or more, and more preferably 5 μm or more. If the average particle size of the solder particles is smaller than 0.5 μm, a good solder joint with the terminal cannot be obtained, and reliability tends to deteriorate. The upper limit of the average particle size of the solder particles may be 50 μm or less, 30 μm or less, preferably 20 μm or less, and more preferably 10 μm or less.

[0054] The maximum diameter of the solder particles can be 200% or less of the average particle diameter, preferably 150% or less of the average particle diameter, and more preferably 120% or less of the average particle diameter. When the maximum diameter of the solder particles is within the above range, the solder particles can be sandwiched between the terminals and the terminal rows can be joined by melting the solder particles.

[0055] The solder particles may also be aggregates of a plurality of solder particles. In the case of an aggregate of a plurality of solder particles, the size of the aggregate may be set to be equal to the average particle size of the solder particles. The size of the aggregate can be determined by observation with an electron microscope or an optical microscope.

[0056] The lower limit of the mass ratio range of the amount of solder particles is preferably 10 wt% or more, more preferably 20 wt% or more, and even more preferably 30 wt% or more, and the upper limit of the mass ratio range of the amount of solder particles is 70 wt% or less, more preferably 60 wt% or less, and even more preferably 50 wt% or less.

[0057] If the amount of solder particles is too small, excellent conductivity cannot be obtained, while if the amount is too large, the insulation between terminals is easily impaired, making it difficult to obtain excellent conductivity reliability. When the solder particles are present in a thermosetting binder, the volume ratio may be used, and when producing a thermosetting connecting material (before the solder particles are present in the binder), the mass ratio may be used. The mass ratio can be converted to a volume ratio based on the specific gravity of the compound or the compounding ratio.

[0058] The solder particles are preferably dispersed in a thermosetting binder, and may be arranged randomly or with a certain regularity. Examples of regular arrangements include lattice arrangements such as a square lattice, a hexagonal lattice, an oblique lattice, and a rectangular lattice. The solder particles may also be arranged as aggregates in which a plurality of particles are aggregated. In this case, the arrangement of the aggregates in a plan view of the thermosetting connecting material may be regular or random, similar to the arrangement of the solder particles described above.

[0059] [Flux components] As the flux component, it is preferable to use carboxylic acids such as levulinic acid, maleic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, etc. This not only allows for good solder joints to be obtained, but also allows the flux to function as a curing agent for epoxy resin when an epoxy resin is blended.

[0060] Alternatively, blocked carboxylic acids, in which the carboxyl group is blocked with alkyl vinyl ether, can be used as flux compounds. This allows for control of the temperature at which the fluxing effect and hardener function are exerted. Furthermore, improved solubility in resins can reduce unevenness in mixing and application during film formation.

[0061] [Thermosetting binder] Examples of thermosetting binders (insulating binders) include thermal radical polymerization resin compositions containing a (meth)acrylate compound and a thermal radical polymerization initiator, thermal cationic polymerization resin compositions containing an epoxy compound and a thermal cationic polymerization initiator, and thermal anionic polymerization resin compositions containing an epoxy compound and a thermal anionic polymerization initiator. Known pressure-sensitive adhesive compositions may also be used. The term "(meth)acrylic monomer" refers to both acrylic and methacrylic monomers.

[0062] In the following, a specific example will be described, taking as an example a thermal anionic polymerization type resin composition containing a solid epoxy resin, a liquid epoxy resin, and an epoxy resin curing agent.

[0063] The solid epoxy resin is not particularly limited as long as it is solid at room temperature and has one or more epoxy groups in the molecule, and may be, for example, a bisphenol A type epoxy resin, a biphenyl type epoxy resin, etc. This allows the film shape to be maintained. Here, room temperature refers to the range of 20°C ± 15°C (5°C to 35°C) as specified in JIS Z 8703.

[0064] The liquid epoxy resin is not particularly limited as long as it is liquid at room temperature, and may be, for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a urethane-modified epoxy resin.

[0065] The amount of the liquid epoxy resin to be blended is preferably 160 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 70 parts by mass or less, per 100 parts by mass of the solid epoxy resin. If the amount of the liquid epoxy resin to be blended is too large, it becomes difficult to maintain the film shape.

[0066] The epoxy resin curing agent is not particularly limited as long as it is a heat curing agent that initiates curing by heat, and examples thereof include anionic curing agents such as amines and imidazoles, and cationic curing agents such as sulfonium salts. The curing agent may be microencapsulated to provide resistance to the solvent used in forming the film.

[0067] [Other additives] In addition to the insulating binder and solder particles described above, the thermosetting connecting material can contain various additives conventionally used in heat-curable adhesives, provided that the effects of the present invention are not impaired. The particle size of the additive is preferably smaller than the average particle size of the solder particles, but there are no particular limitations as long as it does not impede the bonding between terminals. For example, a spacer may be added to adjust the balance. For example, monodispersed silica (e.g., "Hi-Presica" by Ube Exsymo Co., Ltd.) may be appropriately added as a spacer to match the particle size of the solder.

[0068] The thermosetting connecting material can be obtained, for example, by mixing an insulating binder and solder particles in a solvent, applying the mixture to a predetermined thickness on a release-treated film using a bar coater, and then drying to volatilize the solvent. Alternatively, the mixture may be applied to a release-treated film using a bar coater and then pressurized to a predetermined thickness. To improve the dispersibility of the solder particles, it is preferable to apply a high shear force while the material contains the solvent. For example, a known batch-type planetary mixing device can be used. The residual solvent content of the thermosetting connecting material is preferably 2% or less, more preferably 1% or less.

[0069] <3. Method for manufacturing connector> The method for manufacturing a connector in this embodiment involves placing a connector, which has a second terminal row arranged on its bottom surface and a step-absorbing portion formed to absorb the steps on the bottom surface, on a substrate having a first terminal row via a thermosetting connecting material containing solder particles and a flux component, and then connecting the first terminal row and the second terminal row by thermally curing the thermosetting connecting material at a temperature above the melting point of the solder particles without pressing the connector. This absorbs the steps on the bottom surface, allowing the terminals to be arranged at a finer pitch and the connector to be made smaller.

[0070] 8 to 12, the following steps will be described: (A) providing a thermosetting connecting material on the first terminal row of the substrate; (B) placing a connector on the thermosetting connecting material; and (C) joining the first terminal row of the substrate and the second terminal row of the connector using a reflow furnace set at a temperature equal to or higher than the melting point of the solder particles. Components similar to those in the connector shown in FIG. 1 are designated by the same reference numerals, and their description will be omitted here.

[0071] [Process (A)] Fig. 8 is a cross-sectional view showing an example of a substrate, and Fig. 9 is a cross-sectional view showing a state in which a thermosetting connecting material is provided on terminals of the substrate. As shown in Figs. 8 and 9, in step (A), a thermosetting connecting material 33 containing solder particles 31 is provided on a first terminal row 11 of a substrate 10.

[0072] Step (A) may be a step of forming a thermosetting connecting paste into a film on a substrate, or may be a temporary attachment step of adhering a thermosetting connecting film onto a substrate at low temperature, as is used for conventional conductive films and anisotropic conductive films, or may be a lamination step of laminating a thermosetting connecting film onto a substrate.

[0073] When step (A) is a temporary bonding step, the thermosetting connecting film can be applied to the substrate under known conditions, which is economically advantageous since only minimal changes are required, such as the installation or modification of tools, from the existing equipment.

[0074] When step (A) is a lamination step, for example, a pressure laminator is used to laminate the thermosetting connection film onto the substrate. The lamination step may be a vacuum pressure laminator. When conventional conductive films or anisotropic conductive films are temporarily attached using a heat and pressure tool, the width of the film is limited by the width of the tool. However, in the lamination step, a heat and pressure tool is not used, so it is expected that a relatively wide width can be mounted at once.

[0075] In step (A), the lower limit of the ratio of the average particle size of the solder particles to the thickness of the thermosetting connecting material is, as described above, preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, which makes it easier to sandwich the solder particles between the terminals and makes it possible to accommodate fine-pitch terminal rows.

[0076] [Process (B)] 10 is a cross-sectional view schematically illustrating the alignment of the terminal row of the substrate with the terminal row of the connector. As shown in FIG. 10, in step (B), for example, a tool 60 is used to align the terminal row 11 of the substrate 10 with the terminal row 31 of the connector 30, and the connector 30 is placed on the thermosetting connecting material 20. The tool 60 preferably includes a suction mechanism for suctioning the connector 20. Since self-alignment by soldering cannot be expected in this technology, it is desirable to accurately align the connector 20 and fix it with the thermosetting connecting material 33 in step (B).

[0077] [Process (C)] Fig. 11 is a cross-sectional view showing the state in which the connector is placed on the substrate, and Fig. 12 is a cross-sectional view showing the state in which the substrate and connector are heated in a reflow furnace. As shown in Fig. 11 and Fig. 12, in step (C), the first terminal row 11 of the substrate 10 and the second terminals 21 of the connector 20 are joined using a reflow furnace set at a temperature equal to or higher than the melting point of the solder particles 31.

[0078] The reflow furnace can heat and bond the components without mechanical pressure or load, thereby minimizing damage to the board 10 and connector 20. Furthermore, because there is no load, the amount of movement of solder particles is small, making it possible to accommodate fine-pitch terminal rows.

[0079] As the reflow furnace, an atmospheric pressure reflow furnace is preferred from the viewpoint of simplicity, but an atmospheric pressure reflow furnace, a vacuum reflow furnace, an atmospheric pressure oven, an autoclave (pressure oven), or the like may also be used.

[0080] The lower limit of the peak temperature (maximum temperature reached) in the reflow furnace should be equal to or higher than the temperature at which the solder particles melt and the thermosetting binder begins to harden, and is preferably 150°C or higher, more preferably 180°C or higher, and even more preferably 200°C or higher. The upper limit of the peak temperature in the reflow furnace is 300°C or lower, more preferably 290°C or lower, and even more preferably 280°C or lower. This allows the first terminal row 11 of the substrate 10 and the second terminal row 21 of the connector 20 to be joined 32.

[0081] According to the method for manufacturing a connector according to this embodiment, the step on the bottom surface can be absorbed, allowing for finer pitch terminals and a smaller connector. Furthermore, when the thermosetting connecting material is a thermosetting binder, the resin melting during the reflow process, the sandwiching of solder particles between the terminals, and the solder melting and resin hardening can be optimized by matching the temperature rise, maintenance, and temperature drop during the reflow process with the thermosetting behavior of the thermosetting connecting material. The thermosetting behavior of the thermosetting connecting material can be determined by DSC measurement or viscosity measurement using a rheometer.

[0082] <4. Connector> Next, we will explain the terminal structure of a connector that applies this technology. Conventional connectors are surface-mounted using solder, so the terminal rows extend from the inside of the connector to the outside. This creates an open end called a stub, which can have a negative effect on frequency characteristics. For example, the open end has the frequency characteristic of resonating at a frequency where the length is 1 / 4 wavelength, and the signal level at that frequency becomes 0.

[0083] In connectors that use this technology, the terminal rows do not need to extend outward from the bottom surface, which increases the degree of freedom in terminal structure and makes it possible to select a terminal structure with excellent high-frequency characteristics. Below, we simulated combinations of plug and receptacle terminal structures and evaluated them using S parameters (Scattering parameters).

[0084] Fig. 13 is a perspective view showing the connector structure used in the simulation, and Fig. 14 is a cross-sectional view showing an example of the connector structure used in the simulation. The wiring board model was a flexible printed circuit (FPC) with a coverlay, with a wiring pitch of 0.35 mm and a wiring thickness of 18 μm, and the wiring width was optimized. The wiring width at which the impedance becomes 100 Ω is 0.25 mm.

[0085] As shown in Figures 13 and 14, a simulation was performed on a connector connection using a coplanar differential line, with a plug mounted on the first FPC 71 and a receptacle mounted on the second FPC 72. The plug was selected from the shapes shown in Figures 15 to 18, and the receptacle was selected from the shapes shown in Figures 19 to 22. The effect of the combination of plug and receptacle on transmission characteristics was evaluated using a transmission signal S21 and a reflected signal S11. The transmission signal S21 is a signal that passes through terminal B of the second FPC 72 when a signal is input from terminal A of the first FPC 71, and the absolute value in decibels indicates the insertion loss from terminal A to terminal B. The reflected signal S11 is a signal that is reflected to terminal A when a signal is input from terminal A of the first FPC 71, and the absolute value in decibels indicates the return loss of terminal A.

[0086] FIG. 15A is a cross-sectional view showing a first configuration example of a plug (Plug-1), and FIG. 15B is a cross-sectional view showing a second configuration example of a plug (Plug-2). The first configuration example includes a connecting portion 81a that extends linearly from a first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 82b that bends vertically (Y-axis direction) from connecting portion 81a, extends linearly, and has a semicircular shape that extends inward of connecting portion 81a to form a second end. The second configuration example is bilaterally symmetrical to the first configuration example and includes a connecting portion 82a that extends linearly from a first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 82b that bends vertically (Y-axis direction) from connecting portion 82a, extends linearly, and has a semicircular shape that extends inward of connecting portion 82a to form a second end. The first configuration example is implemented with the orientation of the end of the wiring of the first FPC71 aligned with the orientation of the first end, and the second configuration example is implemented with the orientation of the end of the wiring of the first FPC71 aligned with the opposite orientation of the first end.

[0087] FIG. 16(A) is a cross-sectional view showing a third configuration example (Plug-3) of the plug, and FIG. 16(B) is a cross-sectional view showing a fourth configuration example (Plug-4) of the plug. The third configuration example includes a connecting portion 83a that extends linearly from a first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 83b that bends vertically (Y-axis direction) from connecting portion 83a, extends linearly, and has a semicircular shape extending outside connecting portion 83a to form a second end. The fourth configuration example is bilaterally symmetrical to the third configuration example and includes a connecting portion 84a that extends linearly from a first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 84b that bends vertically (Y-axis direction) from connecting portion 84a, extends linearly, and has a semicircular shape extending outside connecting portion 84a to form a second end. That is, the third and fourth configuration examples are obtained by extending the semicircular shape of the first and second configuration examples outward from the connecting portion 83a. The third configuration example is mounted with the end of the wiring of the first FPC 71 oriented in the same direction as the opposite direction of the first end, and the fourth configuration example is mounted with the end of the wiring of the first FPC 71 oriented in the same direction as the first end.

[0088] 17A is a cross-sectional view showing a first-length (L) configuration example of the plug (Plug-1 Loop), and FIG. 17B is a cross-sectional view showing a second-length (L) configuration example of the plug (Plug-2 Loop). The first-length configuration example includes a connecting portion 85a that extends linearly from the first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 85b that bends vertically (Y-axis direction) from the connecting portion 85a, extends linearly, has a semicircular shape, extends inside the connecting portion 85a, and is connected to the connecting portion 85a via a semicircular shape. The second-length configuration example is bilaterally symmetrical to the first-length configuration example and includes a connecting portion 86a that extends linearly from the first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 86b that bends vertically (Y-axis direction) from the connecting portion 86a, extends linearly, has a semicircular shape, extends inside the connecting portion 86a, and is connected to the connecting portion 86a via a semicircular shape. That is, the 1L and 2L configuration examples are the first and second configuration examples, respectively, in which the second end is connected to the connection portion by a semicircular shape. The 1L configuration example is mounted with the end of the wiring of the first FPC 71 aligned with the first end, and the 2L configuration example is mounted with the end of the wiring of the first FPC 71 aligned with the opposite direction of the first end.

[0089] 18A is a cross-sectional view showing a third-level (3L) configuration example of the plug (Plug-3 Loop), and FIG. 18B is a cross-sectional view showing a fourth-level (4L) configuration example of the plug (Plug-4 Loop). The third-level configuration example includes a connecting portion 87a that extends linearly from the first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 86b that bends vertically (Y-axis direction) from the connecting portion 87a, extends linearly, has a semicircular shape, and is connected to the connecting portion 86a via a semicircular shape. The fourth-level configuration example is symmetrical to the third-level configuration example and includes a connecting portion 88a that extends linearly from the first end in the horizontal direction (X-axis direction) and is connected to a wiring, and a male vertical fitting portion 88b that bends vertically (Y-axis direction) from the connecting portion 88a, extends linearly, has a semicircular shape, and is connected to the connecting portion 88a via a semicircular shape. That is, the 3L and 4L configuration examples are the same as the 3rd and 4th configuration examples, except that the second end is connected to the connecting portion in a semicircular shape. The 3L configuration example is mounted with the end of the wiring of the first FPC 71 aligned with the opposite direction of the first end, and the 4L configuration example is mounted with the end of the wiring of the first FPC 71 aligned with the direction of the first end.

[0090] 19 is a cross-sectional view showing a first configuration example (Receptacle-0) of a receptacle. The first configuration example includes a connecting portion 91a that extends linearly in the horizontal direction (X-axis direction) from a first end and is connected to the wiring; a vertical portion 91b that bends vertically (Y-axis direction) from connecting portion 91a and extends linearly; and a female vertical mating portion 91c that extends linearly in the vertical direction (Y-axis direction) from vertical portion 91b in a semicircular shape to the outside of connecting portion 91a, bends outward in the horizontal direction (X-axis direction), extends linearly, bends inward again in the vertical direction (Y-axis direction), and bends further inward to form a semicircular second end. The first configuration example is mounted with the end of the wiring of second FPC 72 aligned with the opposite direction of the first end.

[0091] FIG. 20 is a cross-sectional view showing a second configuration example (Receptacle-1) of a receptacle. The second configuration example includes a connecting portion 92a that extends linearly in the horizontal direction (X-axis direction) from the first end and is connected to the wiring; a vertical portion 92b that bends vertically (Y-axis direction) from the connecting portion 92a and extends linearly; and a female vertical mating portion 92c that extends linearly in the vertical direction (Y-axis direction) from the vertical portion 92b in a semicircular shape toward the inside of the connecting portion 92a in the vertical direction (Y-axis direction), bends outward in the horizontal direction (X-axis direction), extends linearly, bends inward again in the vertical direction (Y-axis direction), and bends further inward to form a semicircular second end. That is, the second configuration example is the first configuration example in which the connecting portion is bent toward the female vertical mating portion. The second configuration example is mounted with the end of the wiring of the second FPC 72 aligned with the first end.

[0092] 21 is a cross-sectional view showing a third configuration example (Receptacle-2) of a receptacle. The third configuration example includes a vertical portion 93a extending linearly in the vertical direction (Y-axis direction) from a first end, a connecting portion 93b bending horizontally (X-axis direction) from vertical portion 93a, extending linearly, and connected to wiring, and a female vertical mating portion 93c bending inward in the vertical direction (Y-axis direction) from connecting portion 93b, bending again inward to form a semicircular second end, and having vertical portion 93a and connecting portion 93b as components. The third configuration example is mounted so that vertical portion 93a faces inward relative to the orientation of the end of the wiring of second FPC 72.

[0093] 22 is a cross-sectional view showing a fourth configuration example (Receptacle-3) of the receptacle. The fourth configuration example is bilaterally symmetrical to the third configuration example, and includes a vertical portion 94a extending linearly in the vertical direction (Y-axis direction) from a first end, a connecting portion 94b bending horizontally (X-axis direction) from the vertical portion 94a, extending linearly, and connected to the wiring, and a female vertical mating portion 94c bending inward in the vertical direction (Y-axis direction) from the connecting portion 94b, bending again inward to form a semicircular second end, and having the vertical portion 94a and the connecting portion 94b as components. The fourth configuration example is mounted so that the vertical portion 94a faces outward relative to the orientation of the end of the wiring of the second FPC 72.

[0094] [High frequency characteristics of the first to fourth configuration examples (Plug-1 to Plug-4)] FIG. 23 is a graph showing the transmission signal S21 when a plug of the first configuration example (Plug-1) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and FIG. 24 is a graph showing the reflected signal S11 when a plug of the first configuration example (Plug-1) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0095] Figure 25 is a graph showing the transmission signal S21 when a plug of the second configuration example (Plug-2) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 26 is a graph showing the reflected signal S11 when a plug of the second configuration example (Plug-2) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0096] Figure 27 is a graph showing the transmission signal S21 when a plug of the third configuration example (Plug-3) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 28 is a graph showing the reflected signal S11 when a plug of the third configuration example (Plug-3) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0097] Figure 29 is a graph showing the transmission signal S21 when a plug of the fourth configuration example (Plug-4) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 30 is a graph showing the reflected signal S11 when a plug of the fourth configuration example (Plug-4) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0098] From the graphs shown in Figures 23 to 30, it was found that the combinations of plug and receptacle terminal structures are, for example, preferably a receptacle of the first configuration example (Receptacle-0) or the second configuration example (Receptacle-1) for a plug of the first configuration example (Plug-1), preferably a receptacle of the fourth configuration example (Receptacle-3) for a plug of the second configuration example (Plug-2), preferably a receptacle of the first configuration example (Receptacle-0) or the second configuration example (Receptacle-1) for a plug of the third configuration example (Plug-3), and preferably a receptacle of the fourth configuration example (Receptacle-3) for a plug of the fourth configuration example (Plug-4).

[0099] [High frequency characteristics of 1L to 4L configuration examples (Plug-1 Loop to Plug-4 Loop)] FIG. 31 is a graph showing the transmission signal S21 when a plug of the 1L configuration example (Plug-1 Loop) is connected to a receptacle of the 1st to 4th configuration examples (Receptacle-0 to Receptacle-3), and FIG. 32 is a graph showing the reflected signal S11 when a plug of the 1L configuration example (Plug-1 Loop) is connected to a receptacle of the 1st to 4th configuration examples (Receptacle-0 to Receptacle-3).

[0100] Figure 33 is a graph showing the transmission signal S21 when a plug of the second L configuration example (Plug-2 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 34 is a graph showing the reflected signal S11 when a plug of the second L configuration example (Plug-2 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0101] Figure 35 is a graph showing the transmission signal S21 when a plug of the 3L configuration example (Plug-3 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 36 is a graph showing the reflected signal S11 when a plug of the 3L configuration example (Plug-3 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0102] Figure 37 is a graph showing the transmission signal S21 when a plug of the 4L configuration example (Plug-4 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3), and Figure 38 is a graph showing the reflected signal S11 when a plug of the 4L configuration example (Plug-4 Loop) is connected to a receptacle of the first to fourth configuration examples (Receptacle-0 to Receptacle-3).

[0103] From the graphs shown in Figures 31 to 38, it was found that the combinations of plug and receptacle terminal structures are, for example, preferably a receptacle of the third configuration example (Receptacle-2) or the fourth configuration example (Receptacle-3) for a plug of the first configuration example (Plug-1 Loop), preferably a receptacle of the third configuration example (Receptacle-2) or the fourth configuration example (Receptacle-3) for a plug of the second configuration example (Plug-2 Loop), preferably a receptacle of the third configuration example (Receptacle-2) or the fourth configuration example (Receptacle-3) for a plug of the third configuration example (Plug-3 Loop), and preferably a receptacle of the third configuration example (Receptacle-2) or the fourth configuration example (Receptacle-3) for a plug of the fourth configuration example (Plug-4 Loop).

[0104] [Simulation evaluation] In conventional solder mounting, the terminals extend outward from the bottom surface of the connector, and only the connection of the plug of the fourth configuration example (Plug-4) with the receptacle of the first configuration example (Receptacle-0), or the inverted combination, is possible. Furthermore, in connectors for solder mounting, one side of each terminal always has the opposite direction of electrical flow, resulting in the creation of stubs. Furthermore, conventional solder mounting has a high solder thickness in the Z direction of 0.1 to 1 mm, making it unsuitable for high-frequency characteristics.

[0105] On the other hand, connections using the thermosetting connecting material of the present technology eliminate the need for terminals to extend outward from the bottom surface of the connector, allowing the connector to select the terminal orientation for both terminals and the direction of current flow, thereby reducing the effect of stubs and improving high-frequency characteristics. Furthermore, by using a loop structure for the plug, the effect of stubs can be further reduced. Furthermore, the thickness of the thermosetting connecting material is 1 to 30 μm, about one-tenth the thickness of solder, thereby improving high-frequency characteristics.

[0106] This technology enables the use of high-frequency compatible areas that were previously unavailable with B2B connectors, and can expand that range. This means that connectors with excellent high-frequency characteristics can now be used in communication electronic devices such as smartphones. Furthermore, by using high-frequency compatible connectors, if a board breaks, simply replacing the board can be done more cheaply than with coaxial connectors. [Example]

[0107] <5. Example> In this example, an anisotropic conductive film containing solder particles as a thermosetting connecting material was produced. Then, using the anisotropic conductive film, a plug and a receptacle board-to-board connector were mounted on a board, and initial conductivity evaluation of the mounted body and conductivity evaluation after an insertion / removal test were performed. However, this example is not limited to these.

[0108] [Initial continuity evaluation] For plug and receptacle assembly samples, the resistance was measured when a current of 1 mA was passed between the connector terminal and the corresponding board terminal, and the median value was calculated. Assembly samples with a median resistance value of 1.0 Ω or less were evaluated as "OK," and all other assembly samples were evaluated as "NG."

[0109] [Conductivity evaluation after insertion / removal test] A plug mounting sample and a receptacle mounting sample were subjected to a 10-cycle insertion / extraction test. After the insertion / extraction test, the plug mounting sample and the receptacle mounting sample were evaluated in the same way as the initial conductivity evaluation.

[0110] [Preparation of ACF-A] As shown in Table 1, an anisotropic conductive film (ACF-A) was fabricated using 80 parts by weight of solid epoxy resin (bisphenol F epoxy resin, Mitsubishi Chemical Corporation, JER4007P, softening point 108°C), 20 parts by weight of liquid epoxy resin (dicyclopentadiene-based epoxy resin, ADEKA Corporation, EP4088L), 5 parts by weight of epoxy resin curing agent (imidazole-based curing agent, Shikoku Chemical Industries Co., Ltd., Curesol 2P4MHZ-PW), 3 parts by weight of flux compound (glutaric acid (1,3-propanedicarboxylic acid), Tokyo Chemical Industry Co., Ltd.), and 50 parts by weight of solder particles with an average particle size of 30 μm (MCP-137, 5N Plus Inc., Sn-58Bi alloy, solidus temperature 138°C). The minimum melt viscosity of the anisotropic conductive film was 6.1 Pa·s, and the minimum melt viscosity temperature was 114°C. The exothermic peak temperature of the anisotropic conductive film was 163°C.

[0111] Solid epoxy resin and liquid epoxy resin dissolved in PMA (propylene glycol monomethyl ether acetate) were mixed with a flux compound dissolved in MEK (methyl ethyl ketone) and an epoxy resin hardener. Solder particles were dispersed in this mixed solution, and then the solution was applied to a PET (polyethylene terephthalate) film using a gap coater so that the thickness after solvent drying was the average solder particle diameter + 5 μm, producing an anisotropic conductive film (ACF-A). Drying was performed at 70°C for 5 minutes.

[0112] [Preparation of ACF-B] As shown in Table 1, an anisotropic conductive film (ACF-B) was fabricated in the same manner as ACF-A, except that solder particles (MCP-137, 5N Plus Inc., Sn-58Bi alloy, solidus temperature 138°C) with an average particle size of 20 μm were used. The minimum melt viscosity of the anisotropic conductive film was 6.1 Pa s, and the minimum melt viscosity temperature was 114°C. The exothermic peak temperature of the anisotropic conductive film was 163°C.

[0113] [Preparation of ACF-C] As shown in Table 1, an anisotropic conductive film (ACF-C) was fabricated in the same manner as ACF-A, except that solder particles (MCP-137, 5N Plus Inc., Sn-58Bi alloy, solidus temperature 138°C) with an average particle size of 10 μm were used. The minimum melt viscosity of the anisotropic conductive film was 6.1 Pa s, and the minimum melt viscosity temperature was 114°C. The peak exothermic temperature of the anisotropic conductive film was 163°C.

[0114] [Preparation of ACF-D] As shown in Table 1, an anisotropic conductive film (ACF-D) was prepared by blending 15 parts by weight of liquid epoxy resin (EP828 manufactured by Mitsubishi Chemical Corporation), 20 parts by weight of phenoxy resin (YP50 manufactured by Nippon Steel Chemical Co., Ltd.), 18 parts by weight of butadiene-acrylonitrile rubber (XER-91 manufactured by JSR Corporation), 4 parts by weight of hydroxyl-containing acrylic rubber (SG-80H manufactured by Nagase ChemteX Corporation), 40 parts by weight of a microcapsule-type amine-based curing agent (Novacure HX3941HP manufactured by Asahi Kasei E-materials Corporation), and 50 parts by weight of solder particles (MCP-137, 5N Plus Inc., Sn-58Bi alloy, solidus temperature 138) with an average particle size of 30 μm.

[0115] Phenoxy resin and liquid epoxy resin dissolved in PMA (propylene glycol monomethyl ether acetate) were mixed with butadiene-acrylonitrile rubber, hydroxyl-containing acrylic rubber, and a microencapsulated amine-based curing agent. Solder particles were dispersed in this mixed solution, which was then applied to a PET (polyethylene terephthalate) film using a gap coater so that the thickness after solvent drying was 5 μm greater than the average particle diameter of the solder particles, producing an anisotropic conductive film (ACF-D). Drying was carried out at 70°C for 5 minutes.

[0116] [Table 1]

[0117] Example 1 Plug and receptacle board-to-board connectors (Hirose Corporation, BM23FR0.6-20DS / DP) were prepared. The bottom surface of the connector had a step (undulation) of about 20 μm. Then, as shown in Figures 2 to 4, for each plug and receptacle connector, the lead terminals extending toward the outside of the connector were bent toward the bottom surface of the connector to make the height of the terminal surface even. The minimum height (distance) between the terminal surface and the bottom surface of the connector was 50 μm. Furthermore, as shown in Figures 2 and 3, the reinforcing portions were scraped off for each plug and receptacle connector.

[0118] Additionally, a flexible printed circuit board (Dexerials Corporation evaluation FPC, Ni-Au plated) corresponding to the plug and a rigid board (Dexerials evaluation glass epoxy board, 18 μm thick Cu pattern, Ni-Au plated) corresponding to the receptacle were prepared.

[0119] The plug was aligned on a flexible substrate via an anisotropic conductive film and fixed at room temperature without applying any load. The receptacle was aligned on a rigid substrate via an anisotropic conductive film and fixed at room temperature without applying any load. The plug was then mounted on the flexible substrate, and the receptacle was mounted on the rigid substrate by reflow, producing a plug mounting sample and a receptacle mounting sample of Example 1. The reflow conditions were 150°C to 260°C for 100 seconds, with a peak temperature of 260°C. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after an insertion / removal test.

[0120] <Example 2> Except for using ACF-B as the anisotropic conductive film, plug mounting samples and receptacle mounting samples of Example 2 were fabricated in the same manner as Example 1. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after the insertion / removal test.

[0121] Example 3 Except for using ACF-C as the anisotropic conductive film, plug mounting samples and receptacle mounting samples of Example 3 were fabricated in the same manner as Example 1. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after the insertion / removal test.

[0122] <Comparative Example 1> Except for using ACF-D as the anisotropic conductive film, plug mounting samples and receptacle mounting samples of Comparative Example 1 were fabricated in the same manner as in Example 1. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after the insertion / removal test.

[0123] <Comparative Example 2> ACF-B was prepared as an anisotropic conductive film.

[0124] A plug and receptacle board-to-board connector (Hirose Corporation, BM23FR0.6-20DS / DP) was prepared. The bottom surface of the connector had a step (undulation) of about 20 μm. The lead terminals and reinforcement parts extending outward from each connector of the plug and receptacle were left as they were.

[0125] Additionally, a flexible printed circuit board (Dexerials Corporation evaluation FPC, Ni-Au plated) corresponding to the plug and a rigid board (Dexerials evaluation glass epoxy board, Ni-Au plated) corresponding to the receptacle were prepared.

[0126] The plug was aligned on a flexible substrate via an anisotropic conductive film and fixed at room temperature without applying any load. The receptacle was aligned on a rigid substrate via an anisotropic conductive film and fixed at room temperature without applying any load. The plug was then mounted on the flexible substrate, and the receptacle was mounted on the rigid substrate by reflow, to produce a plug mounting sample and a receptacle mounting sample of Comparative Example 2. The reflow conditions were 150°C to 260°C for 100 seconds, with a peak temperature of 260°C. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after an insertion / removal test.

[0127] <Comparative Example 3> Except for using ACF-C as the anisotropic conductive film, a plug mounting sample and a receptacle mounting sample for Comparative Example 3 were fabricated in the same manner as Comparative Example 2. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after the insertion / removal test.

[0128] <Comparative Example 4> Except for using ACF-D as the anisotropic conductive film, a plug mounting sample and a receptacle mounting sample of Comparative Example 4 were fabricated in the same manner as Comparative Example 2. Table 2 shows the initial conductivity evaluation results for the plug mounting sample and the receptacle mounting sample, as well as the conductivity evaluation results after the insertion / removal test.

[0129] [Table 2]

[0130] The ACF-D used in Comparative Examples 1 and 4 was for thermocompression bonding and did not contain a flux compound, so the plug and receptacle mounting samples did not have initial conductivity and could not be connected. The plug and receptacle board-to-board connectors used in Comparative Examples 2 and 3 required a large mounting surface because the lead terminals extended outward. Furthermore, the plug and receptacle board-to-board connectors used in Comparative Examples 2 and 3 could not be connected due to a step on the bottom of the connector.

[0131] On the other hand, the plug and receptacle board-to-board connectors used in Examples 1 to 3 had terminal rows on the bottom surface of the connector, which absorbed the steps on the bottom surface of the connector, and the anisotropic conductive film contained solder particles and a flux compound, allowing for connection. This allowed for the terminal rows to be fine-pitched, and the connector to be miniaturized.

[0132] The receptacle used in Examples 1 to 3 has a connection area of ​​120 μm × 170 μm, with L (Line) / S (Space) = 120 μm / 230 μm. However, by using solder particles with an average particle diameter of 10 μm, it is possible, in principle, to achieve a connection area of ​​10,000 μm with L / S of 50 μm / 50 μm and a line length of 200 μm. 2 It is possible to achieve a fine pitch of up to (50 μm x 200 μm). [Explanation of symbols]

[0133] 10 substrate, 11 first terminal row, 20 connector, 21 second terminal row, 30 thermosetting connecting material, 31 solder particles, 32 solder joint, 33 thermosetting connecting material, 40 plug, 41A first male vertical mating row, 41B second male vertical mating row, 42A first terminal row, 42B second terminal row, 43 insulating resin, 50 receptacle, 51A first female vertical mating row, 51B second female vertical mating row, 52A first terminal row, 52B second terminal row, 53 insulating resin, 60 tool, 71 first FPC, 72 second FPC, 81a, 82a connection portion, 81b, 82b male vertical mating portion, 83a, 84a connection portion, 83b, 84b Male vertical mating portions, 85a, 86a; Connection portions, 85b, 86b; Male vertical mating portions, 87a, 88a; Connection portions, 87b, 88b; Male vertical mating portions, 91a, 92a; Connection portions, 91b, 92b; Vertical portions, 91c, 92c; Female vertical mating portions, 93a, 94a; Vertical portions, 93b, 94b; Connection portions, 93c, 94c; Female vertical mating portions, 140; Plug, 141A; First male vertical mating row, 141B; Second male vertical mating row, 142A; First lead terminal row, 142B; Second lead terminal row, 143; Insulating resin, 150; Receptacle, 151A; First female vertical mating row, 151B; Second female vertical mating row, 152A; First lead terminal row, 152B Second lead terminal row, 153 insulating resin

Claims

1. a substrate having a first terminal row; a connector having a second terminal row; an adhesive layer formed by hardening a thermosetting connecting material that connects the first terminal row and the second terminal row; the second terminal row is disposed on a bottom surface of the connector and forms a step absorbing portion that absorbs a step on the bottom surface; A connecting body, wherein the thermosetting connecting material contains solder particles and a flux component.

2. The bottom surface of the connector has a step having a height within a predetermined range, 2. The connector according to claim 1, wherein the difference between the maximum and minimum heights of the terminal surfaces in said second terminal row is smaller than said predetermined height range.

3. 3. The connection body according to claim 1, wherein the difference between the maximum and minimum heights of the terminal faces in the second terminal row is smaller than the average particle diameter of the solder particles.

4. 4. The connection body according to claim 1, wherein the second terminal row extends from the outside to the inside of the bottom surface of the connector.

5. 5. The connection body according to claim 1, wherein the solder particles have an average particle size of 30 [mu]m or less.

6. 6. The connector according to claim 1, wherein the minimum distance between the terminals in the second terminal row is 0.8 mm or less.

7. The connection body according to claim 1 , wherein the connector does not have a reinforcing portion.

8. A connector used for the connection body according to any one of claims 1 to 7.

9. A thermosetting connecting material used for the connecting body according to any one of claims 1 to 7.

10. a connector having a second terminal row disposed on a bottom surface thereof and a step absorbing portion formed thereon to absorb a step on the bottom surface thereof is placed on a substrate having a first terminal row via a thermosetting connecting material containing solder particles and a flux component; The method for manufacturing a connection body includes thermally curing the thermosetting connection material at a temperature equal to or higher than the melting point of the solder particles without pressing the connector, thereby connecting the first terminal row and the second terminal row.

11. The method for manufacturing a connection body according to claim 10, wherein the thermal curing is performed by reflow.

12. 12. The method for manufacturing a connection body according to claim 10, wherein the solder particles have an average particle size of 30 [mu]m or less.

13. 13. The method for manufacturing a connection body according to claim 10, wherein the minimum distance between terminals in the second terminal row is 0.8 mm or less.

14. a terminal row arranged on a bottom surface having a step of a predetermined height; A connector, wherein the difference between the maximum and minimum heights of the terminal faces in the terminal row is smaller than the height of the step.

15. The connector according to claim 14, wherein the terminal row extends from the outside to the inside of the bottom surface of the connector.

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