JP2018133562A - Connection structure, anisotropic adhesive material, and manufacturing method of connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure superior in heat resistance and dimensional stability.SOLUTION: A connection structure includes a ceramic substrate 310 having substrate terminals, an electronic component 200 having component terminals electrically connected to the substrate terminals respectively and facing the ceramic substrate 310, and an anisotropic adhesive material 110 including metal coated resin particles for electrically connecting the substrate terminals and the component terminals and bonding the ceramic substrate and the electronic component 200. The size of the ceramic substrate 310 is 10 cmor less, and the size of each of the substrate terminals is 500000 μmor less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connection structure, an anisotropic adhesive material, and a method for manufacturing the connection structure.

  In recent years, in order to cope with IoT (Internet of Things), devices equipped with cameras, various sensors, communication devices, and the like are becoming popular.

  Such a functional module such as a camera, various sensors, or a communication device is often mounted at a high density by providing minute terminals on a small substrate. Therefore, there has been a demand for a technique capable of stably anisotropically connecting to a substrate having minute terminals.

  Here, as substrates for functional modules or electronic components, glass epoxy substrates, flexible substrates, glass substrates, and the like are common. For example, Patent Document 1 below discloses a technique for suppressing warpage of a glass substrate due to heat when a liquid crystal driving IC (Integrated Circuit) is mounted on the glass substrate using an anisotropic conductive film. Yes.

JP2015-118998A

  However, as disclosed in Patent Document 1, a conventional substrate such as a glass substrate has low heat resistance. Therefore, when anisotropic connection is performed by thermocompression that involves heating, warping due to heat, heat shrinkage, and the like. , And dimensional stability was low.

  On the other hand, as the substrate and terminals are miniaturized, tolerances for dimensions become smaller. Therefore, there has been a demand for a connection structure, an anisotropic adhesive material, and a method for manufacturing the connection structure that are less susceptible to dimensional variations due to heat or the like.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved connection structure, anisotropic adhesion, which is superior in heat resistance and dimensional stability. It is to provide a material and a method for manufacturing a connection structure.

In order to solve the above problems, according to one aspect of the present invention, an electronic component having a ceramic substrate having a substrate terminal and component terminals electrically connected to the substrate terminal and facing the ceramic substrate is provided. And an anisotropic adhesive material that includes metal-coated resin particles that electrically connect the substrate terminal and the component terminal, and that bonds the ceramic substrate and the electronic component, the size of the ceramic substrate A connection structure is provided in which the size is 10 cm ² or less and the size of each of the substrate terminals is 500000 μm ² or less.

  The ceramic substrate may have a thickness of 1.0 mm or less.

  The ceramic substrate may be a printed wiring board using a ceramic material.

  A camera module, a sensor module, a MEMS module, or a high-frequency element may be mounted on the ceramic substrate.

  The anisotropic adhesive material may include a polymer obtained by radical polymerization of an acrylate monomer.

  The acrylate monomer may include an epoxy acrylate monomer.

  The content of the epoxy acrylate monomer may be 2% by mass or more and 15% by mass or less in solid mass ratio with respect to the total mass of the resin component of the anisotropic adhesive material.

The anisotropic adhesive material further includes a phenoxy resin and an elastomer,
20 mass% or more and 40 mass% or less may be sufficient as solid content ratio with respect to the total mass of the resin component of the said anisotropic adhesive material.

  The acrylate monomer may include a carboxy acrylate monomer.

  The content of the carboxyacrylate monomer may be 3% by mass or more and 8% by mass or less in solid mass ratio with respect to the total mass of the resin component of the anisotropic adhesive material.

In order to solve the above problems, according to another aspect of the present invention, there is provided a ceramic substrate having a substrate terminal of 500,000 μm ² or less and a size of 10 cm ² or less, and a component. An anisotropic adhesive material for anisotropically conductively connecting an electronic component having a terminal, wherein the anisotropic adhesive material includes metal-coated resin particles and an acrylate monomer. Is done.

  The acrylate monomer may include at least one of epoxy acrylate and carboxyl acrylate.

  The anisotropic adhesive material may be a film body.

In order to solve the above problem, according to another aspect of the present invention, a step of placing a ceramic substrate having substrate terminals, and a metal coating on a surface of the ceramic substrate on which the substrate terminals are provided. Providing an anisotropic adhesive material including resin particles, placing an electronic component having a component terminal on the anisotropic adhesive material so that the substrate terminal and the component terminal face each other, and heating And the step of adhering the ceramic substrate and the electronic component by pressing, the size of the ceramic substrate is 10 cm ² or less, and the size of each of the substrate terminals is 500,000 μm ^2. The following manufacturing method of the connection structure is provided.

  The ceramic substrate and the electronic component may be bonded with a pressing pressure of 0.5 MPa or more and 6 MPa or less.

  The ceramic substrate and the electronic component may be bonded at a heating temperature of 120 ° C. or higher and 180 ° C. or lower.

  The anisotropic adhesive material is a film body provided in advance, and may be provided by attaching the film body to the ceramic substrate. Such a film body can be formed by applying the anisotropic adhesive material on a general base film such as PET (PolyEthylene Terephthalate).

  With the above configuration, anisotropic connection suitable for the ceramic substrate can be performed using the ceramic substrate having high heat resistance.

  As described above, according to the present invention, it is possible to provide a connection structure superior in heat resistance and dimensional stability.

It is sectional drawing which shows the structure of the connection structure which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the anisotropic adhesive material suitable for the connection structure which concerns on the embodiment.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Connection structure>
(Configuration of connection structure)
First, with reference to FIG. 1, the structure of the connection structure 1 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a cross-sectional view showing a configuration of a connection structure 1 according to an embodiment of the present invention.

  As shown in FIG. 1, the connection structure 1 according to this embodiment is a structure in which an electronic component 200 and a ceramic substrate 310 are anisotropically connected by an anisotropic adhesive material 110. In addition, for example, a functional module 320 is mounted on the ceramic substrate 310.

  The ceramic substrate 310 is a substrate formed by sintering an inorganic substance. Specifically, the ceramic substrate 310 is a substrate-like sintered body obtained by forming a powder of an inorganic compound such as an oxide, carbide, nitride, or boride and then baking it by heat treatment.

  The material of the ceramic substrate 310 is, for example, various glasses such as borosilicate glass or quartz glass, aluminum oxide, aluminum nitride, germanium, zirconium dioxide, silicon carbide, silicon nitride, barium titanate, lead zirconate titanate, boron nitride, Alternatively, zinc oxide or the like may be used. More specifically, the ceramic substrate 310 may be an aluminum oxide (so-called alumina) substrate, a low temperature co-fired ceramic substrate (Low Temperature Co-fired Ceramic: LTCC), or a high temperature co-fired ceramic substrate (High Temperature Co-fired Ceramic: HTCC) or the like.

  In the present invention, the ceramic substrate 310 does not include a non-sintered substrate such as a semiconductor substrate such as silicon and a glass substrate such as fused quartz. Therefore, the ceramic substrate 310 can be considered to be different from a so-called IC chip (for example, a driver IC used for general COG (Chip On Glass) connection).

  On the surface of the ceramic substrate 310, a substrate terminal and a wiring connected to the substrate terminal are provided. As an example, substrate terminals and wirings may be formed on the surface of the ceramic substrate 310 by a printing method using a metal such as tungsten, molybdenum, titanium, silver, or copper. That is, the ceramic substrate 310 may be a form of a printed wiring board (PWB). The ceramic substrate 310 may be provided with one or more substrate terminals. From the viewpoint of general anisotropic connection, the ceramic substrate 310 is provided with a plurality of substrate terminals. A plurality of substrate terminals provided on the ceramic substrate 310 are arranged in a predetermined direction to form a terminal arrangement. The substrate terminal represents a part that contributes to the connection of the ceramic substrate 310, and may represent a connection part in the wiring in addition to the electrode.

  Further, the ceramic substrate 310 may be a multilayer wiring substrate formed by laminating a plurality of ceramic substrates and then sintering them. In such a multilayer wiring board, the wiring provided in each layer may be connected via a conductive material embedded in a via penetrating the interlayer.

In the connection structure 1 according to the present embodiment, the size of the ceramic substrate 310 is 10 cm ² or less, preferably 5 cm ² or less, more preferably 1 cm ² or less. In order to make it easy to mount the functional module 320 on the connection structure 1 after the electronic component 200 and the ceramic substrate 310 are connected, the minimum length of the ceramic substrate 310 is rectangular. In this case, it may be 0.3 cm or more and 2 cm or less. For example, the reason why the length of the minimum side of the ceramic substrate 310 is preferably 0.3 cm or more is that it is easy to carry the substrate before and after the connection process. For the same reason, the length of the minimum side of the ceramic substrate 310 is more preferably 0.5 cm or more, and further preferably 0.7 cm or more. When the length of the minimum side of the ceramic substrate 310 is 2 cm or less, the volume of the connection structure is reduced, so that the product on which the connection structure is mounted can be downsized. Therefore, the length of the minimum side of the ceramic substrate 310 is preferably 2 cm or less, more preferably 1.8 cm or less, and even more preferably 1.5 cm or less for the same reason. Therefore, when the ceramic substrate 310 is rectangular, the area of the ceramic substrate 310 may be preferably 4 cm ² or less, and the length of each side of the ceramic substrate 310 at this time is a value within the above-described preferable range. It can design suitably from these combinations. Ceramics have high heat resistance, so that dimensional fluctuation due to thermal shrinkage is small, and dimensional stability during processing and mounting is high. Therefore, ceramic can be suitably used as a material for a minute substrate having a small tolerance for dimensions. The lower limit value of the size of the ceramic substrate 310 is not particularly limited, but is 0.1 cm ² in consideration of processing accuracy and the like. The size of the ceramic substrate 310 is preferably 0.6 cm ² or more, more preferably 0.8 cm ² or more, and further preferably 1.0 cm ² or more from the viewpoint of handleability. preferable.

  In addition, although ceramic has a high hardness, it is easily broken brittlely. Therefore, it is easy to cut in one direction (so-called chocolate break) by making a notch or the like. Therefore, by using ceramic as a material, the ceramic substrate 310 can easily form a minute substrate.

  Furthermore, since the ceramic substrate 310 is made of an inorganic ceramic, dust is less likely to be generated when the substrate is cut than a substrate containing an organic material such as a glass epoxy substrate or a resin substrate. Even if dust is generated, the generated dust is inorganic, so that it is difficult for the dust to adhere to the ceramic substrate 310, the electronic component 200, and the functional module 320, and the dust can be easily removed. is there. Therefore, the connection structure 1 according to the present embodiment is suitably used for a functional module having no dust (or very little dust). Such a connection structure 1 may be required for precision devices such as cameras and sensors.

  The thickness of the ceramic substrate 310 is preferably 1.0 mm or less, and more preferably 0.5 mm or less. Since ceramic has high strength, even when the substrate is thinly formed, deformation such as warpage is unlikely to occur. Therefore, the ceramic substrate 310 is not easily deformed even when it is formed thinner. In addition, since ceramic has high impact resistance, the ceramic substrate 310 is less likely to be cracked even when it is formed thinner. Therefore, the ceramic substrate 310 can be formed thinner while maintaining strength and dimensional stability, and thus the connection structure 1 can be further reduced in weight. The lower limit value of the thickness of the ceramic substrate 310 is not particularly limited, but is 0.1 mm, for example, in consideration of processing accuracy.

  When the ceramic substrate 310 is formed as a multilayer wiring substrate, the thickness of the ceramic substrate 310 described above is the total thickness of the entire multilayer wiring substrate. However, this thickness does not include the height of the substrate terminal provided on the ceramic substrate 310.

  The thickness of the ceramic substrate 310 is a known thickness measuring device (thickness gauge, high-precision caliper or micrometer (for example, high-precision digimatic micrometer manufactured by Mitutoyo Corporation), etc.) It can be obtained by measuring with. The height of the substrate terminal provided on the ceramic substrate 310 can be obtained by using a known measurement method (observation with an electron microscope such as SEM or a metal microscope, or a three-dimensional measuring instrument manufactured by Keyence Corporation). it can. Further, the height variation of the substrate terminals provided on the ceramic substrate 310 can be measured by using a surface roughness meter (for example, Surfcorder SE-400 manufactured by Kosaka Laboratory Co., Ltd.) (see JP2015-130426). .

Further, the size of each substrate terminal provided on the ceramic substrate 310 is 500000 μm ² (0.005 cm ² ) or less, and preferably 200000 μm ² (0.002 cm ² ) or less. Since the ceramic substrate 310 has high dimensional stability, even if the size of the substrate terminal is very small, the positional shift between the component terminal of the electronic component 200 and the substrate terminal of the ceramic substrate 310 is unlikely to occur. Therefore, by using ceramic as a material, the size of the substrate terminals provided on the surface of the ceramic substrate 310 can be reduced, so that the terminals and wirings can be arranged on the ceramic substrate 310 with higher density. . In addition, the ceramic substrate 310 is less susceptible to deformation such as heat shrinkage and warping, and has high dimensional stability. Therefore, the ceramic substrate 310 can stably perform anisotropic connection with the component terminal of the electronic component 200 even when the size of the substrate terminal is further reduced. The lower limit value of the size of the substrate terminal provided on the ceramic substrate 310 is not particularly limited, but is, for example, 40000 μm ² (0.0004 cm ² ) in consideration of processing accuracy. However, depending on the size of the ceramic substrate 310, the size of the substrate terminal may be smaller than 40000 μm ² (0.0004 cm ² ). Since the size of the substrate terminal depends on the manufacturing method of the substrate terminal (connecting portion), it is not limited in general. For example, the size of the substrate terminal may be 10000 μm ² or more per piece. . If the size of the substrate terminal is 10,000 μm ² or more, it can be said that the substrate terminal has an area that does not hinder the capture of the conductive particles by anisotropic connection. The above description does not exclude the size of the substrate terminal is less than 1 per 10000 ^2.

  The electronic component 200 is an electronic circuit having component terminals on the surface that are electrically connected to the substrate terminals of the ceramic substrate 310. The electronic component 200 may be, for example, an integrated circuit element such as a flexible printed circuit (FPC) substrate or an integrated circuit (IC) chip. Similarly to the ceramic substrate 310, the electronic component 200 may be an electronic circuit in which terminals and wirings are provided on a ceramic substrate. Similarly to the ceramic substrate 310, the electronic component 200 is provided with a plurality of component terminals, and the plurality of component terminals provided on the electronic component 200 are arranged in a predetermined direction to form a terminal arrangement. The component terminal represents a part that contributes to the connection of the electronic component 200, and may represent a connection part in the wiring in addition to the electrode.

  The anisotropic adhesive material 110 includes conductive particles and anisotropically connects the ceramic substrate 310 and the electronic component 200. For example, the anisotropic adhesive material 110 is an adhesive mainly containing a curable resin that is cured by energy rays such as ultraviolet rays or heat, and conductive particles.

  The anisotropic adhesive material 110 cures the curable resin that is the main agent between the electronic component 200 and the ceramic substrate 310 by heating, and bonds the two together. Further, the anisotropic adhesive material 110 compresses the conductive particles between the component terminal of the electronic component 200 and the substrate terminal of the ceramic substrate 310 by pressing, and forms a conduction path between the two. According to the anisotropic adhesive material 110, the ceramic substrate 310 and the electronic component 200 can be electrically and mechanically connected.

  The conductive particles contained in the anisotropic adhesive material 110 are not particularly limited as long as they are known, but as an example, metal-coated resin particles are preferable. Specifically, the metal-coated resin particles are nickel, copper, gold, the surface of core resin particles such as styrene-divinylbenzene copolymer, benzoguanamine resin, cross-linked polystyrene resin, acrylic resin, or styrene-silica composite resin. Alternatively, particles coated with a metal such as palladium. The metal coating on the metal-coated resin particles may have two layers.

  Since the surface of the ceramic substrate 310 is large, the distance between the component terminal of the electronic component 200 and the substrate terminal of the ceramic substrate 310 is likely to vary. When the conductive particles are metal-coated resin particles, the core resin particles of the metal-coated resin particles have high resilience, so that the followability to the distance between the component terminal of the electronic component 200 and the substrate terminal of the ceramic substrate 310 is improved. To improve the conductivity between the terminals when the distance between the terminals varies.

  Further, even if the distance between the component terminal of the electronic component 200 and the substrate terminal of the ceramic substrate 310 fluctuates due to deterioration of the adhesive property of the anisotropic adhesive material 110 or the like, the metal-coated resin particle is a core resin particle. Due to the repulsive property, the conductivity between the terminals can be maintained. Therefore, by using the metal-coated resin particles as the conductive particles contained in the anisotropic adhesive material 110, the connection structure 1 can suppress fluctuation due to the environment to the minimum.

  Furthermore, since the metal-coated resin particles are easier to manage the particle size distribution than the metal particles, they can be formed with a particle size distribution having a sharp peak by aligning the particle sizes. For this reason, when the metal-coated resin particles are used as the conductive particles, it becomes easy to design the anisotropic adhesive material 110 capable of stably obtaining conduction.

  The particle diameter of the metal-coated resin particles (that is, the number average value of the diameters of the metal-coated resin particles) may be, for example, 3 μm or more and 30 μm or less, and preferably 10 μm or more and 20 μm or less. The particle diameter of the metal-coated resin particles can be measured by, for example, a laser diffraction / scattering method or an image type particle size distribution measuring apparatus (for example, FPIA-3000 (manufactured by Malvern)). Further, in order to further reduce the influence of the swell of the surface of the ceramic substrate 310 on the conductivity between the terminals, the particle diameter of the metal-coated resin particles is preferably 10 μm or more. However, when the particle diameter of the metal-coated resin particles is too large, a short circuit may occur when the space between the terminals becomes narrow. Therefore, the particle diameter of the metal-coated resin particles is preferably 30 μm or less.

  Therefore, in the connection structure 1 in which the ceramic substrate 310 and the electronic component 200 are anisotropically connected, the conductive particles contained in the anisotropic adhesive material 110 can be preferably metal-coated resin particles.

  The anisotropic adhesive material 110 is, for example, a film-like anisotropic conductive film (ACF: Anisotropic Conductive Film) formed by applying a curable resin on a base film made of PET (PolyEthylene Terephthalate) or the like. May be. Further, the anisotropic adhesive material 110 may be a paste-like anisotropic conductive paste (ACP: Anisotropic Conductive Paste) containing a curable resin. An anisotropic conductive film has the advantage of being excellent in handleability during connection. On the other hand, since the anisotropic conductive paste can omit the step of forming into a film, there is an advantage that it is excellent in terms of cost, and there is also an advantage that the width and thickness can be adjusted according to the state at the time of connection. . Whether the anisotropic adhesive material 110 is used as an anisotropic conductive film or an anisotropic conductive paste can be appropriately selected depending on the terminal layout and size of the object to be connected and the connection method.

  The thickness of the anisotropic adhesive material 110 or the thickness when applied with a paste (including the case where the anisotropic adhesive material 110 is pinpointed at a connection point) (hereinafter, the thickness of the anisotropic adhesive material 110) Is abbreviated to be 10 μm or more in order to improve the trapping property of the metal-coated resin particles and make it less susceptible to the above-described surface waviness of the ceramic substrate 310. Alternatively, the thickness of the anisotropic adhesive material 110 may be 0.95 times or more, preferably 1 or more times, more preferably 1.2 or more times the particle diameter of the metal-coated resin particles. When the thickness of the anisotropic adhesive material 110 is thin, the amount of resin that flows at the time of connection is relatively small. Therefore, the lower limit of the thickness of the anisotropic adhesive material 110 may be the above-described value.

  In addition, the upper limit of the thickness of the anisotropic adhesive material 110 is not particularly limited. However, if the thickness of the anisotropic adhesive material 110 is too thick, the amount of the resin protruding from the anisotropic adhesive material 110 is too large after connection. Can be considered. Therefore, the thickness of the anisotropic adhesive material 110 may be 50 μm or less, preferably 40 μm or less, and more preferably 30 μm or less. Alternatively, the thickness of the anisotropic adhesive material 110 may be 1.4 times or less of the total height of both terminals to be connected, preferably 1.2 times or less, more preferably 1 time or less. Good. Further, when the thickness of the anisotropic adhesive material 110 is 0.8 times or less of the total height of both terminals to be connected, the protruding structure of the resin of the anisotropic adhesive material 110 is further suppressed, whereby the connection structure The effect that accommodation of the body 1 is not inhibited can be expected. However, suppression of protrusion does not indicate a state in which no protrusion of resin exists. On the other hand, when the thickness of the anisotropic adhesive material 110 becomes too thin, there is a concern that resin filling between terminals to be connected is insufficient. Therefore, the lower limit of the thickness of the anisotropic adhesive material 110 is preferably 0.3 times or more of the total height of both terminals to be connected, and more preferably 0.4 times or more. In general, the thickness of the anisotropic adhesive material 110 is approximately equal to the total height of both terminals to be connected. However, if the lower limit value of the thickness of the anisotropic adhesive material 110 is the value described above, if a defect is found in the connection structure 1 after connection, the ceramic substrate 310 and the electronic component 200 are used for connection again by repairing. It may be possible. When connecting a functional module on which relatively expensive parts are mounted, the anisotropic adhesive material 110 may be required to have such characteristics. Therefore, it is preferable that the lower limit of the thickness of the anisotropic adhesive material 110 satisfies the above numerical range condition.

  The curable resin included in the anisotropic adhesive material 110 may be, for example, an acrylic monomer or an epoxy monomer.

  The functional module 320 is a component having a single function or a plurality of functions. The functional module 320 is electrically connected to substrate terminals provided on the ceramic substrate 310, and further electrically connected to the electronic component 200 via the ceramic substrate 310 and the anisotropic adhesive material 110. ing. The functional module 320 may be, for example, a camera module, a sensor module such as an acceleration sensor or an infrared sensor, a MEMS (Micro Electro Mechanical System) module such as a gyroscope or an actuator, or a high-frequency element such as a high-frequency filter or a high-frequency switch. Good.

  In the connection structure 1 according to the present embodiment, the functional module 320 is mounted on the ceramic substrate 310 that is not easily deformed. Therefore, even if the module or the element has low resistance to deformation, the functional module 320 can be obtained by devising the connection process (for example, by applying a relatively high load to the ceramic substrate 310 that is difficult to deform). It is possible to use. Further, in the connection structure 1 according to the present embodiment, the functional module 320 is mounted on the ceramic substrate 310 that hardly generates dust when the substrate is cut. Therefore, a module or an element (including a camera module) that is likely to be defective due to dust or the like can be used as the functional module 320. That is, examples of the applicable range of the connection object of the connection structure 1 according to the present embodiment can be preferably exemplified by those having low resistance to deformation and precise ones that are liable to be defective due to dust.

(Use of connection structure)
As described above, since the connection structure 1 includes the ceramic substrate 310, it is resistant to heat and impact. Moreover, the connection structure 1 is easy to maintain the electrical connection between the ceramic substrate 310 and the electronic component 200 due to the followability of the metal-coated resin particles contained in the anisotropic adhesive material 110. Since such a connection structure 1 has high weather resistance, it can be used suitably for equipment or devices used in harsh environments such as outdoors. For example, the connection structure 1 can be used to connect a functional module 320 mounted on a mobile body such as an automobile or a drone.

  Moreover, since the connection structure 1 can easily maintain an anisotropic connection to an external environment such as heat, the connection structure 1 can be suitably used for devices that are subjected to high-temperature and high-pressure autoclave treatment. For example, the connection structure 1 is a medical device that is subjected to autoclave sterilization, a biochemical laboratory device, an agribusiness device such as a vegetable factory, or a chemical laboratory device that is synthesized or molded by autoclaving. It can be used to connect a functional module 320 mounted on a composite material manufacturing apparatus such as carbon fiber.

  Moreover, since the connection structure 1 can ensure sufficient electrical continuity even with a smaller functional module 320, it can be suitably used for electronic devices and the like that are required to be smaller and lighter. For example, the connection structure 1 can be used for connection of a functional module 320 mounted on a mobile terminal such as a mobile phone, a smartphone, or a tablet terminal.

  Moreover, since the connection structure 1 can ensure sufficient electrical continuity even with a smaller functional module 320, it affects the operation of the device even for devices that are not equipped with a conventional sensor or the like. It can be suitably used without giving. Sensors and the like are used, for example, to assist the operation of these devices. For example, the connection structure 1 can be used to connect a functional module 320 mounted on an industrial machine, a robot arm, a home appliance, an infrastructure system, a surveillance camera system, or the like.

  In recent years, application examples of sensors have become more diverse. Therefore, the object to which the connection structure 1 is applied is merely an example, and the application object of the connection structure 1 is not limited to these.

<2. Manufacturing method of connection structure>
Next, a method for manufacturing the connection structure 1 according to this embodiment will be described.

  First, a ceramic substrate 310 provided with substrate terminals on the surface is prepared. For example, a functional module 320 is connected to the ceramic substrate 310.

  Subsequently, a layer made of the anisotropic adhesive material 110 is formed on the surface of the ceramic substrate 310 where the substrate terminals are provided. The layer made of the anisotropic adhesive material 110 may be formed by attaching an anisotropic conductive film, or may be formed by applying an anisotropic conductive paste by a known coating method (note that The anisotropic adhesive material 110 may be provided pinpoint as described above.

  However, in the method for manufacturing the connection structure 1 according to the present embodiment, the layer made of the anisotropic adhesive material 110 is preferably formed by attaching an anisotropic conductive film. Since the ceramic substrate 310 used in this embodiment has a small area, anisotropic connection can be achieved with higher positioning accuracy by using an anisotropic conductive film that has better workability than the anisotropic conductive paste. It can be carried out.

  Further, since the anisotropic conductive paste tends to have lower adhesiveness of the curable resin than the anisotropic conductive film, when the layer made of the anisotropic adhesive material 110 is formed with the anisotropic conductive paste, the ceramic The positioning between the substrate 310 and the electronic component 200 is likely to be shifted. Since the ceramic substrate 310 used in the present embodiment has a small area, a positioning tolerance between the ceramic substrate 310 and the electronic component 200 is small. Therefore, in the manufacturing method of the connection structure 1 according to the present embodiment, it is preferable to use an anisotropic conductive film capable of performing anisotropic connection with higher positioning accuracy.

  Subsequently, the electronic component 200 is placed on the layer made of the anisotropic adhesive material 110 and temporarily fixed. Specifically, the electronic component 200 is made of an anisotropic adhesive material 110 such that a component terminal provided on the surface of the electronic component 200 and a substrate terminal provided on the surface of the ceramic substrate 310 face each other. Placed on the layer. Thereafter, the positional relationship between the ceramic substrate 310 and the electronic component 200 is temporarily fixed by being heated and pressed to such an extent that the anisotropic adhesive material 110 is not cured. The temporarily fixed heating temperature and the pressing pressure may be, for example, a heating temperature and a pressing pressure lower than the main press bonding described later.

  Next, the ceramic substrate 310 and the electronic component 200 are electrically and mechanically connected to each other by being heated and pressed (also referred to as main pressing) by a known thermocompression bonding apparatus. Specifically, the ceramic substrate 310 and the electronic component 200 are heated to a temperature at which the anisotropic adhesive material 110 is cured, and pressed to a pressure at which a conductive path is formed by the conductive particles compressed between the terminals. . As a result, the ceramic substrate 310 and the electronic component 200 are electrically and mechanically connected by the anisotropic adhesive material 110.

  Here, in the manufacturing method of the connection structure 1 according to the present embodiment, the pressing pressure at the time of the main pressing may be 0.5 MPa or more and 6 MPa or less. When the pressing pressure exceeds 6 MPa, the functional module 320 mounted on the ceramic substrate 310 may be deformed, which is not preferable. In addition, when the pressing pressure is less than 0.5 MPa, it is not preferable because there is a possibility that a conductive path by the conductive particles is not reliably formed between the substrate terminal of the ceramic substrate 310 and the component terminal of the electronic component 200. The pressing pressure at the time of the main pressure bonding may be preferably 0.5 MPa or more and 2 MPa or less.

  Moreover, in the manufacturing method of the connection structure 1 according to the present embodiment, the heating temperature during the main press bonding may be 120 ° C. or higher and 180 ° C. or lower. When the heating temperature exceeds 180 ° C., it is not preferable because the functional module 320 having low heat resistance may be damaged by heat. In addition, when the heating temperature is less than 120 ° C., the curable resin of the anisotropic adhesive material 110 is not cured, and the ceramic substrate 310 and the electronic component 200 may not be securely bonded, which is not preferable. Note that the heating temperature during the main press bonding may be 130 ° C. or higher and 160 ° C. or lower.

  According to the manufacturing method of the connection structure 1 as described above, the ceramic substrate 310 on which the functional module 320 that is weak against heat and deformation is mounted is surely formed by anisotropic connection with the electronic component 200. It is possible.

  In addition, when anisotropically connecting the ceramic substrate 310 and the electronic component 200 using the anisotropic adhesive material 110, the step of injecting an underfill agent between terminals is omitted unlike so-called solder mounting. Therefore, the manufacturing cost can be reduced.

  In addition, about the specific manufacturing apparatus and manufacturing conditions in each process, since a well-known manufacturing apparatus and manufacturing conditions can be applied, detailed description was abbreviate | omitted.

<3. Anisotropic adhesive material>
Then, with reference to FIG. 2, the anisotropic adhesive material 110 suitable for the connection structure 1 which concerns on this embodiment is demonstrated. FIG. 2 is a schematic diagram showing a configuration of the anisotropic adhesive material 110 suitable for the connection structure 1 according to the present embodiment.

  For example, as an environmental test for confirming the connection reliability of the connection structure 1, for example, a test in which the connection structure 1 is left for a long time in an environment of 85 ° C. and 85% RH (also referred to as an 85/85 test). )It has been known. As an environmental test under more severe conditions, a pressure cooker test (also called a PCT test) is known in which the connection structure 1 is left for several hours in high-temperature and high-pressure steam such as about 120 ° C. and 2 atm. Yes.

  In general, in order to confirm the connection reliability of the connection structure 1, a test using a temperature of 85 ° C./humidity of 85% RH (85/85 test) is used as an environmental test condition. However, in the 85/85 test, it takes 500 hours or more before the connection reliability of the connection structure 1 can be evaluated, and more than 1000 hours when evaluating in more detail. It will take. On the other hand, in the PCT (Pressure Cooker Test) test, the connection reliability of the connection structure 1 can be evaluated in a shorter time than the 85/85 test. Therefore, in recent years, it is becoming mainstream to evaluate a test product in a short time by performing a destructive test of the connection structure 1 using a PCT test. Therefore, the anisotropic adhesive material 110 is also required to have characteristics that can be withstood by the PCT test.

  The anisotropic adhesive material 110 described below forms the connection structure 1 having high environmental resistance by connecting the ceramic substrate 310 and the electronic component 200 more firmly. Specifically, an anisotropic adhesive material 110 capable of manufacturing the connection structure 1 that can perform the main press bonding at a low temperature and also exhibits high resistance to the PCT test will be described.

  As shown in FIG. 2, the anisotropic adhesive material 110 includes conductive particles 112 and a resin layer 111. Moreover, the anisotropic adhesive material 110 forms the anisotropic conductive film 100 by apply | coating on base films 120, such as PET, for example. The anisotropic conductive film 100 is stored, for example, in the form of a roll wound around the reel member 100A.

  As described above, the conductive particles 112 are preferably metal-coated resin particles. Specifically, the conductive particles 112 are made of nickel, copper, gold, or palladium on the surface of core resin particles such as styrene-divinylbenzene copolymer, benzoguanamine resin, cross-linked polystyrene resin, acrylic resin, or styrene-silica composite resin. Particles coated with a metal such as

  Further, the particle diameter of the conductive particles 112 (that is, the number average value of the diameters of the conductive particles 112) may be, for example, 3 μm or more and 30 μm or less, and preferably 10 μm or more and 20 μm or less. The particle diameter of the conductive particles 112 can be measured by, for example, a laser diffraction / scattering method or an image type particle size distribution measuring device (for example, FPIA-3000 (manufactured by Malvern)).

  The resin layer 111 includes a film forming resin, a curable resin, and a curing agent. Moreover, the resin layer 111 may further contain additives such as a silane coupling agent, an inorganic filler, a colorant, or an antioxidant, as necessary.

  The film-forming resin is a resin having an average molecular weight of about 10,000 to 80,000. For example, the film forming resin may be an epoxy resin, a modified epoxy resin, a urethane resin, or a phenoxy resin. From the viewpoint of the film formation state and connection reliability, the film forming resin is preferably a phenoxy resin.

  The anisotropic adhesive material 110 according to the present embodiment preferably includes a phenoxy resin and an elastomer such as a urethane resin as a film forming resin.

  In order to increase the connection reliability of the anisotropic adhesive material 110, it is preferable that the film-forming resin contains an elastomer that is a resin of a rubber-like continuous body that is not easily broken by pulling and has high ductility. In particular, the elastomer content is preferably 20% by mass or more and 40% by mass or less in terms of solid mass ratio with respect to the total mass of the film-forming resin of the anisotropic adhesive material 110. Thereby, since the ductility of the anisotropic adhesive material 110 can be increased, the anisotropic adhesive material 110 can increase the adhesive strength between the ceramic substrate 310 and the electronic component 200.

  The curable resin is a monomer that is cured during heating in the main pressure bonding when used in combination with a curing agent, and an acrylic monomer is preferable. For example, the curable resin is methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate. 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclo Acrylic monomers such as pentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) isocyanate, or urethane acrylate Mukoto is preferable. Moreover, these monomers may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  When the curable resin is an acrylic monomer, the heating temperature at the time of the main pressure bonding can be kept lower than other curable resins such as an epoxy monomer. Therefore, according to such an anisotropic adhesive material 110, it is possible to prevent the functional module 320 from being damaged by heating when the connection structure 1 is finally crimped.

  The curable resin more preferably contains at least an epoxy acrylate monomer. In the case of a monomer having an epoxy group such as an epoxy acrylate monomer, the epoxy group and the surface of the ceramic substrate 310 chemically interact with each other, whereby adhesion can be enhanced. Therefore, when the curable resin contains the epoxy acrylate monomer, the anisotropic adhesive material 110 can be more firmly bonded to the ceramic substrate 310 at the time of curing.

  Here, the epoxy acrylate monomer contained in the curable resin preferably has both a vinyl group and a hydroxy group (—OH). Since the surface of the sintered body constituting the ceramic substrate 310 is made of a metal oxide, it is common that a functional group such as an oxo group (═O) is present on the surface of the ceramic substrate 310. Therefore, when the epoxy acrylate monomer has a vinyl group and a hydroxy group, it is presumed that the functional group on the surface of the metal oxide constituting the ceramic substrate 310 and the hydroxy group easily form a hydrogen bond. Moreover, it is guessed that the anisotropic adhesive material 110 containing an epoxy acrylate monomer tends to be in a state where interface adhesion is strong due to radical polymerization of vinyl groups.

  In addition, a carboxy group-containing acrylate monomer or carboxy acrylate that can be expected to have the same effect as the above-described vinyl group and hydroxy group may be blended in the resin layer 111 for adjustment and the like.

  According to such a configuration, the anisotropic adhesive material 110 according to the present embodiment can be applied to the metal oxide (ceramic substrate 310) and the metal oxide even in a relatively severe wet heat resistance test such as a PCT test. It is easy to avoid the occurrence of peeling between the articles to be bonded (electronic component 200).

  In the anisotropic adhesive material 110, since the conductive particles 112 held between the substrate terminal of the ceramic substrate 310 and the component terminal of the electronic component 200 repel, the effect of avoiding such peeling is produced. It is more desirable. In particular, when metal-coated resin particles are used as the conductive particles 112, the metal-coated resin particles are deformed at the time of anisotropic connection, and a certain time is elapsed after the anisotropic connection (that is, the curing of the anisotropic adhesive material 110 is completed). Later, the deformation recovers. In the anisotropic connection, it is common to use metal-coated resin particles as the conductive particles 112 in order to form conduction between opposing electrodes (or terminals). However, as described above, since the metal-coated resin particles have a large repulsive force due to deformation recovery, they can also cause peeling at the electrode (or terminal). Therefore, in order to suppress the occurrence of peeling at the electrode (or terminal) described above, when the wettability of the anisotropic adhesive material 110 to the ceramic substrate 310 is taken into account, the epoxy acrylate monomer has a molecular weight that is not too large. It is preferable to use it. For example, the molecular weight of the epoxy acrylate monomer is preferably 800 to 3000.

  The anisotropic adhesive material 110 according to the present embodiment is not limited to the above-described epoxy acrylate monomer as long as the same effect can be obtained, and may include a dimer, an oligomer, or a polymer. It goes without saying that monomers, dimers, oligomers or polymers may be included.

  The content of the epoxy acrylate monomer is preferably 2% by mass or more and 15% by mass or less in solid mass ratio with respect to the total mass of the resin component of the anisotropic adhesive material 110. When the content of the epoxy acrylate monomer is less than 2% by mass, it is difficult to obtain an effect of enhancing the adhesion by the epoxy acrylate monomer, which is not preferable. When the content of the epoxy acrylate monomer exceeds 15% by mass, the anisotropic adhesive material 110 becomes highly elastic, which is not preferable because the adhesive strength between the ceramic substrate 310 and the electronic component 200 is reduced. . Note that the total mass of the resin component of the anisotropic adhesive material 110 refers to a value obtained by removing the mass of the conductive particles from the total mass of the anisotropic adhesive material 110.

  In addition, if the content of the epoxy acrylate monomer is too small, the above-described effects may not be achieved. Therefore, the content of the epoxy acrylate monomer is preferably 2% by mass or more, more preferably 3% by mass or more, and further preferably 4% by mass or more. On the other hand, if the content of the epoxy acrylate monomer is excessive, the anisotropic adhesive material 110 after curing becomes highly elastic, so that sufficient adhesive strength may not be obtained. Therefore, the content of the epoxy acrylate monomer is preferably 15% by mass or less, more preferably 13% by mass or less, and further preferably 10% by mass or less.

  The curing agent starts, for example, a curing reaction of the curable resin. The curing agent can be appropriately selected and used depending on the type of the curable resin, but may be, for example, a radical polymerization type curing agent that cures the acrylate monomer. In addition, the curing agent may be a curing agent (so-called latent curing agent) that initiates a curing reaction by being activated by a trigger such as heat, light, pressure, or the like, although the reactivity is usually low.

  According to such an anisotropic adhesive material 110, the main pressure bonding can be performed at a low temperature with little influence on the functional module 320, and sufficient reliability is exhibited even in a severe environmental test such as a PCT test. The connection structure 1 can be manufactured.

(Modification)
Next, a modified example of the anisotropic adhesive material 110 suitable for the connection structure 1 according to the present embodiment will be described.

  For example, in an electronic component 200 such as an FPC, a coverlay film may be provided to protect a circuit. However, in FPC, since an olefin resin is used as a protective material when the coverlay film is bonded, the FPC (terminal) may be contaminated by the olefin resin. Since the olefin resin is excellent in releasability and chemically stable, in such a case, the adhesiveness to the anisotropic adhesive material 110 is lowered in the component terminal to which the olefin resin or the like is attached.

  The anisotropic adhesive material 110 to be described below has high resistance to contamination caused by a chemical substance generated when the ceramic substrate 310 and the electronic component 200 are anisotropically connected, and is contaminated by the chemical substance. A strong anisotropic connection is formed even for an object to be bonded. Specifically, an anisotropic adhesive material 110 that exhibits high adhesion to component terminals to which olefinic resin or the like is attached and can firmly bond the ceramic substrate 310 and the electronic component 200 is described. To do.

  The anisotropic adhesive material 110 includes conductive particles 112 and a resin layer 111. Since the conductive particles 112 are as described above, description thereof is omitted here.

  The resin layer 111 includes a film forming resin, a curable resin, and a curing agent. Moreover, the resin layer 111 may further contain additives, such as a silane coupling agent, an inorganic filler, a coloring agent, antioxidant, or a rust inhibitor, as needed.

  The film-forming resin is a resin having an average molecular weight of about 10,000 to 80,000. For example, the film forming resin may be an epoxy resin, a modified epoxy resin, a urethane resin, or a phenoxy resin. From the viewpoint of the film formation state and connection reliability, the film forming resin is preferably a phenoxy resin.

  The curable resin is a monomer that is cured during heating in the main pressure bonding when used in combination with a curing agent, and an acrylic monomer is preferable. For example, the curable resin is methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate. 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclo Acrylic monomers such as pentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) isocyanate, or urethane acrylate Mukoto is preferable. Moreover, these monomers may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Moreover, it may be more preferable that curable resin contains a carboxyacrylate monomer at least. Since the carboxy acrylate monomer contains a highly reactive carboxy group, sufficient adhesion can be maintained even when component terminals or the like to be bonded are contaminated with a low-reactive olefin resin or the like.

  Moreover, it is preferable that content of a carboxyacrylate monomer is 3 mass% or more and 8 mass% or less by solid mass ratio with respect to the total mass of the resin component of the anisotropic adhesive material 110. FIG. When the content of the carboxyacrylate monomer is less than 3% by mass, the effect of enhancing the adhesion by the carboxyacrylate monomer is not seen, which is not preferable. When the content of the carboxyacrylate monomer exceeds 8% by mass, the storage stability of the anisotropic adhesive material 110 is lowered, which is not preferable. Note that the total mass of the resin component of the anisotropic adhesive material 110 refers to a value obtained by removing the mass of the conductive particles from the total mass of the anisotropic adhesive material 110.

  The curing agent starts, for example, a curing reaction of the curable resin. The curing agent can be appropriately selected and used depending on the type of the curable resin, but may be, for example, a radical polymerization type curing agent that cures the acrylate monomer. In addition, the curing agent may be a curing agent (so-called latent curing agent) that initiates a curing reaction by being activated by a trigger such as heat, light, pressure, or the like, although the reactivity is usually low.

  According to such an anisotropic adhesive material 110, even when a component terminal or the like to be bonded is contaminated with a low-reactive chemical substance such as an olefin resin, the connection structure 1 that exhibits sufficient adhesive strength. Can be provided.

  Hereinafter, the connection structure according to the present embodiment and the method for manufacturing the connection structure will be described in more detail with reference to examples. In addition, the Example shown below is an example for showing the feasibility and effect of the connection structure which concerns on this embodiment, and the manufacturing method of a connection structure, and this invention is limited to a following example. It is not a thing.

<Experimental example 1>
(Manufacture of anisotropic conductive film)
The materials shown in Table 1 below were mixed to prepare an anisotropic adhesive material composition. Thereafter, the adjusted anisotropic adhesive material composition was applied onto a release sheet made of PET so that the film thickness after drying was 30 μm and dried. Thereafter, the manufactured anisotropic conductive film was cut into a width of 2.0 mm.

  In Table 1, “YP-50” is a phenoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “Nipporan 5196” is a polyurethane resin with a polycarbonate skeleton manufactured by Tosoh Corporation, and “U-2PPA” "Is a urethane acrylate manufactured by Shin-Nakamura Chemical Co., Ltd.," A-SA "is a monofunctional acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., and" DCP "is a Shin-Nakamura Chemical Co., Ltd. ) “Bipolyl VR-90” is a bisphenol A type epoxy acrylate manufactured by Showa Denko KK, and “KAYAMER PM-2” is phosphoric acid manufactured by Nippon Kayaku Co., Ltd. It is an ester type acrylate, and “dilauroyl peroxide” is a radical generator. The “conductive particles” are conductive particles obtained by applying nickel gold plating to a resin core having a diameter of 20 μm. In addition, all the ratios shown in Table 1 are solid mass ratios, and the unit is “part by mass”.

(Manufacture of connection structure)
First, an FPC made of polyimide resin having a thickness of 25 μm was prepared as an electronic component. The component terminals on the surface of the electronic component were made of nickel / gold plated copper. The height of the component terminals is 12 μm, and the interval in the arrangement direction of the component terminals is 0.4 mm pitch (L / S = 1: 1).

A ceramic substrate made of 0.5 mm thick aluminum oxide was prepared as the ceramic substrate. The substrate terminals on the surface of the ceramic substrate were made of nickel / gold plated tungsten. The height of the substrate terminals is 10 μm, and the intervals in the arrangement direction of the substrate terminals are 0.4 mm pitch (L / S = 1: 1, L = 0.2 mm (200 μm), S = 0.2 mm ( 200 μm)). That is, the size of the substrate terminals in the arrangement direction (that is, the terminal width) is 0.2 mm (200 μm). Furthermore, the size of the ceramic substrate is 14 cm ² . The substrate terminal exists only on one side of the ceramic substrate, and the length of one side of the ceramic substrate on which the substrate terminal exists is about 30 mm (the number of anisotropically connected substrate terminals: 75).

  Next, the anisotropic conductive film manufactured above was affixed on the surface of the ceramic substrate on which the substrate terminals were formed. Thereafter, the electronic component was placed and temporarily fixed on the anisotropic conductive film so that the component terminal faces the ceramic substrate. Furthermore, by using 0.2 mm thick silicon rubber that has been subjected to mold release treatment as a buffer material, the ceramic substrate, anisotropic conductive film, and electronic component that have been temporarily fixed are subjected to main pressure bonding with a pressure bonding tool having a width of 2.0 mm. A connection structure was manufactured. In addition, the conditions of this press-fit were 140 degreeC-1MPa-6 second.

(Evaluation method)
About the connection structure manufactured above, the conduction resistance, the peel strength, and the appearance were evaluated under the three conditions after the initial stage, the 85/85 test, and the PCT test.

  “Initial” refers to a connection structure before the 85/85 test or the PCT test. The 85/85 test was performed by leaving the connection structure in an environment of a temperature of 85 ° C. and a humidity of 85% RH for 1000 hours. Furthermore, the PCT test was performed by leaving the connection structure for 72 hours in an environment of a temperature of 135 ° C., a humidity of 100% RH, and an atmospheric pressure of 3.2 atm.

  The conduction resistance was measured using a digital multimeter (digital multimeter 7561, manufactured by Yokogawa Electric Corporation). Specifically, the resistance value between the FPC and the ceramic substrate was measured using a digital multimeter. The number of terminals measured is 60, and the conduction resistance is an average value of the 60 terminals measured.

The conduction resistance was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: The maximum resistance is less than 0.3Ω.
B: The maximum resistance is 0.3Ω or more and less than 0.4Ω.
C: The maximum resistance is 0.4Ω or more.

  The peel strength was measured using a tensile tester (trade name: Tensilon, manufactured by A & D). Specifically, after placing the connection structure cut to a width of 1 cm horizontally, the tensile strength at which the connection structure peeled when it was pulled at an angle of 90 degrees was measured.

The initial peel strength was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Peel strength is 8 N / cm or more.
B: Peel strength is 6 N / cm or more and less than 8 N / cm.
C: Peel strength is less than 6 N / cm.

The peel strength after the 85/85 test was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Peel strength is 4 N / cm or more.
B: Peel strength is 2 N / cm or more and less than 4 N / cm.
C: Peel strength is less than 2 N / cm.

The appearance after the PCT test was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: No peeling occurred.
B: The area of the peeling generation part is less than 10% of the area of the connection part.
C: The area of the peeling generation part is 10% or more of the area of the connection part.

Furthermore, the comprehensive judgment was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Among 6 items, there are 5 or more A evaluations and no C evaluation.
B: Among 6 items, A evaluation is 4 or less, and C evaluation is absent.
C: One or more C evaluations among 6 items.

  The above results are shown in Table 2 below.

  Referring to the results in Table 2, since the connection structures according to Examples 1 to 6 can anisotropically connect electronic components to a ceramic substrate with a small area with high accuracy, It can be seen that the resistance is extremely low.

  Moreover, since Examples 2-5 use the anisotropic adhesive material suitable for the connection structure according to the present embodiment, the initial conductivity and adhesive strength are good compared to Examples 1 and 6. It can be seen that good electrical conductivity and appearance are maintained even after the PCT test.

  In particular, since Examples 3 and 4 use an anisotropic adhesive material that is more suitable for the connection structure according to this embodiment, the initial conductivity and adhesive strength, and the conductivity and appearance after the PCT test are further improved. It turns out that it is favorable.

  On the other hand, in Examples 1 and 6, since the composition of the anisotropic adhesive material is outside the range suitable for the connection structure according to this embodiment, the initial continuity and adhesive strength, and the continuity after the PCT test. It can be seen that either the appearance or the appearance is not good.

<Experimental example 2>
(Manufacture of anisotropic conductive film)
The materials shown in Table 3 below were mixed to prepare an anisotropic adhesive material composition. Thereafter, the adjusted anisotropic adhesive material composition was applied onto a release sheet made of PET so that the film thickness after drying was 30 μm and dried. Thereafter, the manufactured anisotropic conductive film was cut into a width of 2.0 mm.

  In Table 3, “YP-50” is a bis-A epoxy type phenoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and “FX293” is a fluorene type phenoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. “Nipporan 5196” is a polyurethane resin having a polycarbonate skeleton manufactured by Tosoh Corporation, “U-2PPA” is a urethane acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., and “A-200” is Shin-Nakamura Chemical Co., Ltd. bifunctional acrylate, “4-HBA” is a hydroxyl type monofunctional acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd., “A-SA” is Shin-Nakamura It is a carboxy group type monofunctional acrylate manufactured by Chemical Industry Co., Ltd., and “KAYAMER PM-2” is a phosphate ester acrylate manufactured by Nippon Kayaku Co., Ltd. There, "dilauroyl peroxide" is a radical generator. The “conductive particles” are conductive particles obtained by applying nickel gold plating to a resin core having a diameter of 20 μm. In addition, all the ratios shown in Table 3 are solid mass ratios, and the unit is “part by mass”.

(Manufacture of connection structure)
First, an FPC made of polyimide resin having a thickness of 25 μm was prepared as an electronic component. The component terminals on the surface of the electronic component were made of nickel / gold plated copper. The height of the component terminals is 12 μm, and the interval in the arrangement direction of the component terminals is 0.4 mm pitch (L / S = 1: 1).

  Subsequently, after a 0.05 mm-thickness protective film made of polymethylpentene resin is brought into contact with the component terminal of the prepared electronic component, the component terminal is heated and pressed by a thermocompression bonding device so that the component terminal becomes an olefin. An electronic component contaminated with a resin was produced. Since the melting point of the polymethylpentene resin is 230 ° C., the heating and pressing conditions were 250 ° C.-15 kgF (147 N) -3 minutes.

A ceramic substrate made of 0.5 mm thick aluminum oxide was prepared as the ceramic substrate. The substrate terminals on the surface of the ceramic substrate were made of nickel / gold plated tungsten. The height of the substrate terminals is 10 μm, and the intervals in the arrangement direction of the substrate terminals are 0.4 mm pitch (L / S = 1: 1, L = 0.2 mm (200 μm), S = 0.2 mm ( 200 μm)). That is, the size of the substrate terminals in the arrangement direction (that is, the terminal width) is 0.2 mm (200 μm). Furthermore, the size of the ceramic substrate is 14 cm ² . The substrate terminal exists only on one side of the ceramic substrate, and the length of one side of the ceramic substrate on which the substrate terminal exists is about 30 mm (the number of anisotropically connected substrate terminals: 75).

  Next, the anisotropic conductive film manufactured above was affixed on the surface of the ceramic substrate on which the substrate terminals were formed. Thereafter, an electronic component having a contaminated component terminal was placed and temporarily fixed on the anisotropic conductive film so that the component terminal faces the ceramic substrate. Furthermore, by using 0.2 mm thick silicon rubber that has been subjected to mold release treatment as a buffer material, the ceramic substrate, anisotropic conductive film, and electronic component that have been temporarily fixed are subjected to main pressure bonding with a pressure bonding tool having a width of 2.0 mm. A connection structure was manufactured. In addition, the conditions of this press-fit were 140 degreeC-1MPa-6 second.

(Evaluation method)
About the connection structure manufactured above, conduction resistance and peel strength were evaluated.

  The conduction resistance was measured using a digital multimeter (digital multimeter 7561, manufactured by Yokogawa Electric Corporation). Specifically, the resistance value between the FPC and the ceramic substrate was measured using a digital multimeter. The number of terminals measured is 60, and the conduction resistance is an average value of the 60 terminals measured.

The conduction resistance was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: The maximum resistance is less than 0.3Ω.
B: The maximum resistance is 0.3Ω or more and less than 0.4Ω.
C: The maximum resistance is 0.4Ω or more.

  The peel strength was measured using a tensile tester (trade name: Tensilon, manufactured by A & D). Specifically, after placing the connection structure cut to a width of 1 cm horizontally, the tensile strength at which the connection structure peeled when it was pulled at an angle of 90 degrees was measured.

The peel strength was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Peel strength is 8 N / cm or more.
B: Peel strength is 6 N / cm or more and less than 8 N / cm.
C: Peel strength is less than 6 N / cm.

  The above results are shown in Table 4 below.

  Referring to the results in Table 4, since the connection structures according to Examples 11 to 16 can anisotropically connect electronic components to a ceramic substrate having a small area with high accuracy, the conduction resistance is low. It can be seen that it is extremely low.

  Moreover, since Examples 12-15 use the anisotropic adhesive material suitable for the connection structure which concerns on this embodiment, it is contaminated with the low-reactive olefin resin with respect to Examples 11 and 16. It can be seen that good adhesiveness is exhibited even for the component terminals. In particular, it can be seen that in Example 14, since the anisotropic adhesive material more suitable for the connection structure according to the present embodiment is used, the adhesiveness is further improved.

  On the other hand, in Examples 11 and 16, since the composition of the anisotropic adhesive material is outside the range suitable for the connection structure according to this embodiment, it can be seen that the adhesiveness is lowered.

<Experimental example 3>
(Manufacture of anisotropic conductive film)
The materials shown in Table 5 below were mixed to prepare an anisotropic adhesive material composition. Thereafter, the adjusted anisotropic adhesive material composition was applied onto a release sheet made of PET so that the film thickness after drying was 30 μm and dried. Thereafter, the manufactured anisotropic conductive film was cut into a width of 2.0 mm. The anisotropic adhesive material composition according to Experimental Example 3 is intended to further improve the appearance of the connection structure after the PCT test by adding Aerosil (registered trademark) RY200, which is an inorganic filler.

  In Table 5, “YP-50” is a phenoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “Nipporan 5196” is a polyurethane resin with a polycarbonate skeleton manufactured by Tosoh Corporation, and “U-2PPA” "Is a urethane acrylate manufactured by Shin-Nakamura Chemical Co., Ltd.," A-SA "is a monofunctional acrylate manufactured by Shin-Nakamura Chemical Co., Ltd., and" DCP "is a Shin-Nakamura Chemical Co., Ltd. ) “Bipolyl VR-90” is a bisphenol A type epoxy acrylate manufactured by Showa Denko KK, and “KAYAMER PM-2” is phosphoric acid manufactured by Nippon Kayaku Co., Ltd. It is an ester type acrylate, “Dilauroyl peroxide” is a radical generator, and “Aerosil RY200” is an inorganic fiber manufactured by Nippon Aerosil Co., Ltd. It is over. The “conductive particles” are conductive particles obtained by applying nickel gold plating to a resin core having a diameter of 20 μm. In addition, all the ratios shown in Table 5 are solid mass ratios, and the unit is “part by mass”.

  With respect to “A-SA”, “DCP”, and “Lipoxy VR-90” shown in Table 5, the ratio of the total solid mass of the anisotropic adhesive material composition to 100 mass% was calculated. become that way. In addition, the unit of the ratio shown in Table 6 is “mass%”.

(Manufacture of connection structure)
First, an FPC made of polyimide resin having a thickness of 25 μm was prepared as an electronic component. The component terminals on the surface of the electronic component were made of nickel / gold plated copper. The height of the component terminals is 12 μm, and the interval in the arrangement direction of the component terminals is 0.4 mm pitch (L / S = 1: 1).

A ceramic substrate made of 0.5 mm thick aluminum oxide was prepared as the ceramic substrate. The substrate terminals on the surface of the ceramic substrate were made of nickel / gold plated tungsten. The height of the substrate terminals is 10 μm, and the intervals in the arrangement direction of the substrate terminals are 0.4 mm pitch (L / S = 1: 1, L = 0.2 mm (200 μm), S = 0.2 mm ( 200 μm)). That is, the size of the substrate terminals in the arrangement direction (that is, the terminal width) is 0.2 mm (200 μm). Furthermore, the size of the ceramic substrate is 14 cm ² . The substrate terminal exists only on one side of the ceramic substrate, and the length of one side of the ceramic substrate on which the substrate terminal exists is about 30 mm (the number of anisotropically connected substrate terminals: 75).

  Next, the anisotropic conductive film manufactured above was affixed on the surface of the ceramic substrate on which the substrate terminals were formed. Thereafter, the electronic component was placed and temporarily fixed on the anisotropic conductive film so that the component terminal faces the ceramic substrate. Furthermore, by using 0.2 mm thick silicon rubber that has been subjected to mold release treatment as a buffer material, the ceramic substrate, anisotropic conductive film, and electronic component that have been temporarily fixed are subjected to main pressure bonding with a pressure bonding tool having a width of 2.0 mm. A connection structure was manufactured. In addition, the conditions of this press-fit were 140 degreeC-1MPa-6 second.

(Evaluation method)
About the connection structure manufactured above, similarly to Experimental Example 2, the conduction resistance, the peel strength, and the appearance were evaluated under the three conditions of the initial stage, after the 85/85 test, and after the PCT test.

  “Initial” refers to a connection structure before the 85/85 test or the PCT test. The 85/85 test was performed by leaving the connection structure in an environment of a temperature of 85 ° C. and a humidity of 85% RH for 1000 hours. Furthermore, the PCT test was performed by leaving the connection structure for 72 hours in an environment of a temperature of 135 ° C., a humidity of 100% RH, and an atmospheric pressure of 3.2 atm.

  The conduction resistance was measured using a digital multimeter (digital multimeter 7561, manufactured by Yokogawa Electric Corporation). Specifically, the resistance value between the FPC and the ceramic substrate was measured using a digital multimeter. The number of terminals measured is 60, and the conduction resistance is an average value of the 60 terminals measured.

The conduction resistance was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: The maximum resistance is less than 0.3Ω.
B: The maximum resistance is 0.3Ω or more and less than 0.4Ω.
C: The maximum resistance is 0.4Ω or more.

  The peel strength was measured using a tensile tester (trade name: Tensilon, manufactured by A & D). Specifically, after placing the connection structure cut to a width of 1 cm horizontally, the tensile strength at which the connection structure peeled when it was pulled at an angle of 90 degrees was measured.

The initial peel strength was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Peel strength is 8 N / cm or more.
B: Peel strength is 6 N / cm or more and less than 8 N / cm.
C: Peel strength is less than 6 N / cm.

The peel strength after the 85/85 test was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Peel strength is 4 N / cm or more.
B: Peel strength is 2 N / cm or more and less than 4 N / cm.
C: Peel strength is less than 2 N / cm.

The appearance after the PCT test was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: No peeling occurred.
B: The area of the peeling generation part is less than 10% of the area of the connection part.
C: The area of the peeling generation part is 10% or more of the area of the connection part.

Furthermore, the comprehensive judgment was evaluated according to the following criteria. It shows that A is better than C. In addition, it is preferable that the evaluation is B or more in practical use of the connection structure.
A: Among 6 items, there are 5 or more A evaluations and no C evaluation.
B: Among 6 items, A evaluation is 4 or less, and C evaluation is absent.
C: One or more C evaluations among 6 items.

  The above results are shown in Table 7 below.

  Referring to the results in Table 7, it can be seen that the connection structures according to Examples 21 to 25 can anisotropically connect electronic components to a ceramic substrate having a small area with high reliability. In particular, since Examples 22 and 23 use a suitable anisotropic adhesive material, the initial continuity and adhesive strength are good, and good continuity and appearance are maintained even after the PCT test. I understand that.

  As can be seen from the above results, the connection structure according to the present embodiment can perform good anisotropic connection even with minute terminals by using a ceramic substrate having high heat resistance and high dimensional stability. It is.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Connection structure 100 Anisotropic conductive film 110 Anisotropic adhesive material 111 Resin layer 112 Conductive particle 120 Base film 200 Electronic component 310 Ceramic substrate 320 Functional module

Claims (17)

A ceramic substrate having substrate terminals;
An electronic component having a component terminal electrically connected to each of the substrate terminals and facing the ceramic substrate;
An anisotropic adhesive material that includes metal-coated resin particles that electrically connect the substrate terminal and the component terminal, and bonds the ceramic substrate and the electronic component;
With
The size of the ceramic substrate is 10 cm ² or less, and the size per one of the substrate terminals is 500000 μm ² or less.   The connection structure according to claim 1, wherein the ceramic substrate has a thickness of 1.0 mm or less.   The connection structure according to claim 1, wherein the ceramic substrate is a printed wiring board using a ceramic material.   The connection structure according to any one of claims 1 to 3, wherein a camera module, a sensor module, a MEMS module, or a high-frequency element is mounted on the ceramic substrate.   The connection structure according to any one of claims 1 to 4, wherein the anisotropic adhesive material includes a polymer obtained by radical polymerization of an acrylate monomer.   The connection structure according to claim 5, wherein the acrylate monomer includes an epoxy acrylate monomer.   Content of the said epoxy acrylate monomer is 2 mass% or more and 15 mass% or less in solid mass ratio with respect to the total mass of the resin component of the said anisotropic adhesive material, The connection structure of Claim 6 . The anisotropic adhesive material further includes a phenoxy resin and an elastomer,
Content of the said elastomer is 20 mass% or more and 40 mass% or less by solid mass ratio with respect to the total mass of the resin component of the said anisotropic adhesive material, It is any one of Claims 5-7. The connection structure described.   The connection structure according to claim 5, wherein the acrylate monomer includes a carboxyacrylate monomer.   10. The connection structure according to claim 9, wherein the content of the carboxyacrylate monomer is 3% by mass or more and 8% by mass or less in solid mass ratio with respect to the total mass of the resin component of the anisotropic adhesive material. . An anisotropic adhesive material for anisotropically conductively connecting a ceramic substrate having a substrate terminal of 500,000 μm ² or less and a size of 10 cm ² or less to an electronic component having a component terminal. There,
The anisotropic adhesive material is an anisotropic adhesive material containing metal-coated resin particles and an acrylate monomer.   The anisotropic adhesive material according to claim 11, wherein the acrylate monomer includes at least one of epoxy acrylate and carboxyl acrylate.   The anisotropic adhesive material according to claim 11 or 12, wherein the anisotropic adhesive material is a film body. Placing a ceramic substrate having substrate terminals;
Providing an anisotropic adhesive material containing metal-coated resin particles on the surface of the ceramic substrate on which the substrate terminal is provided;
An electronic component having a component terminal is disposed on the anisotropic adhesive material so that the substrate terminal and the component terminal face each other.
Bonding the ceramic substrate and the electronic component by heating and pressing; and
Including
The size of the ceramic substrate is 10 cm ² or less, and the size per one of the substrate terminals is 500,000 μm ² or less.   The method for manufacturing a connection structure according to claim 14, wherein the ceramic substrate and the electronic component are bonded with a pressing pressure of 0.5 MPa or more and 6 MPa or less.   The method for manufacturing a connection structure according to claim 14 or 15, wherein the ceramic substrate and the electronic component are bonded at a heating temperature of 120 ° C or higher and 180 ° C or lower. The manufacturing method of the connection structure according to any one of claims 14 to 16, wherein the anisotropic adhesive material is a film body provided in advance, and is provided by attaching the film body to the ceramic substrate. Method.

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