JP2020013954A - Board connection structure, micro led display and component mounting method - Google Patents

Abstract

To provide a board connection structure in which an electronic component of micro size, such as a micro LED, and a wiring board are kept in good connection.SOLUTION: A board connection structure connecting multiple electronic components 3 by pressing on a wiring board 4 includes an elastic layer 5 provided on the wiring board 4, and contracting according to the pressing force when the electronic components 3 are pressed, conductive elastic projections 7 provided on electrode pads 6 placed on the elastic layer 5, corresponding to connection terminals 3a provided in respective electronic components 3, and connected with the connection terminals 3a, and an insulating adhesive member 8 provided in a pillar shape at a predetermined position around the elastic projection 7, and bonding the electronic component 3 and the elastic layer 5. When a height difference occurs in the height direction interval of a corresponding connection terminal 3a and the elastic projection 7, at the time of connection of the electronic component 3 and the wiring board 4, the height difference is absorbed by contraction of the elastic layer, the electronic component 3 and the elastic layer 5 are bonded by the adhesive member 8, thus connecting the connection terminal 3a and the elastic projection 7.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a board connection structure for connecting an electronic component to a wiring board, and more particularly to a board connection structure that enables mounting of a small-sized electronic component such as a micro LED (light emitting diode), and a board connection structure for the same. The present invention relates to an adopted micro LED display and a component mounting method for mounting an electronic component on a wiring board.

  2. Description of the Related Art Conventionally, as a substrate connection structure for facilitating connection of a light emitting diode (LED) to a substrate on which a circuit or the like is formed, an LED having a size used for lighting is used by using an anisotropic conductive adhesive (ACA). (Patent Document 1).

JP 2013-53378 A

  However, when the substrate connection structure as in the conventional example is applied to, for example, a micro LED (electronic component) incorporated in a micro LED display, the substrate connection structure also needs to be miniaturized according to the size of the micro LED. In this case, the particle size of the metal particles contained in the anisotropic conductive adhesive is not negligible with respect to the size of the micro LED, which affects the miniaturization of the substrate connection structure. Therefore, it is not preferable to use the above-described anisotropic conductive adhesive for the substrate connection structure for the micro LED.

  In addition to this, when each micro LED is mounted on the wiring base plate by, for example, laser lift off (LLO) processing, a connection failure may occur between the micro LED and the wiring board. Here, the laser lift-off is performed, for example, by bonding a sapphire substrate in which a plurality of micro LEDs are arranged in a matrix on one surface and a wiring substrate, and irradiating a laser on the other surface to remove the sapphire substrate. It refers to peeling and removing. The poor connection may occur, for example, when the sapphire substrate is warped, that is, when the sapphire substrate has non-uniform flatness. Note that the connection failure is not limited to the warpage of the sapphire substrate, but may be caused by other factors such as a variation in the height of the micro LED itself.

  Therefore, the present invention addresses such a problem, and a substrate connection structure in which the connection between an electronic component having a small size such as a micro LED and a wiring substrate is well maintained, and a micro LED employing the substrate connection structure. It is an object to provide a display and a component mounting method for mounting an electronic component on a wiring board.

  In order to achieve the above object, a board connection structure according to the present invention is a board connection structure in which a plurality of electronic components are pressed and connected on a wiring board including a wiring layer for driving the electronic components. An elastic layer provided on a substrate and contracting in accordance with the pressing force when the electronic component is pressed, and disposed on the elastic layer corresponding to the connection terminals provided on each of the electronic components. A conductive elastic protrusion that is provided on the electrode pad that is connected to the connection terminal, and is provided in a columnar shape at a predetermined position around the elastic protrusion, and adheres the electronic component and the elastic layer. An insulating adhesive member that performs the connection between the electronic component and the wiring board, if there is a height difference between the corresponding connection terminals and the elastic projections in the height direction, Absorb the difference by contraction of the elastic layer To bond the electronic component and the elastic layer in the adhesive member, thereby connecting the connection terminal and the elastic protrusions.

  The micro LED display according to the present invention is a micro LED display capable of displaying a color image, and includes a plurality of micro LEDs arranged in a matrix and a wiring board including a wiring layer for driving the micro LEDs. Comprising an LED array substrate, wherein the connection between the micro LED and the wiring board is provided on the wiring board, and when the micro LED is pressed, an elastic layer that contracts in accordance with the pressing force; Corresponding to the connection terminal provided on the micro LED, provided on the electrode pad disposed on the elastic layer, a conductive elastic protrusion connected to the connection terminal, and a conductive elastic protrusion around the elastic protrusion. A connecting element that is provided in a columnar shape at a predetermined position and includes an insulating adhesive member that adheres the micro LED and the elastic layer; In connection with the micro LED and the wiring board, when a height difference occurs in a height direction interval between the corresponding connection terminal and the elastic projection, the height difference is caused by contraction of the elastic layer. Absorbing, the micro LED and the elastic layer are adhered by the adhesive member, and the connection terminal and the elastic protrusion are connected.

  Also, the component mounting method according to the present invention is a method for positioning a plurality of electronic components arranged in a matrix on one surface of a light-transmitting wafer on a wiring board including a wiring layer for driving the electronic components. By pressing the electronic component from the other surface of the wafer and fixing the electronic component, the wafer is peeled off by a laser lift-off process, so that the electronic component is mounted on the wiring board. A step of forming an elastic layer on the wiring substrate, the elastic layer contracting in response to the pressure when the electronic component is pressed, and disposed on the elastic layer corresponding to a connection terminal of the electronic component. Patterning a conductive elastic projection on the electrode pad, forming a via connection between the connection terminal of the electronic component and the wiring layer of the wiring board, and insulating the elastic layer on the elastic layer. Exposing and developing after applying the adhesive, forming an adhesive member in a columnar shape at a predetermined position around the electrode pad, and positioning and pressing the electronic component on the wiring board A step of curing the adhesive member to adhere the electronic component to the wiring substrate, and a step of peeling the wafer by the laser lift-off process.

  According to the substrate connection structure of the present invention, the use of the anisotropic conductive adhesive is unnecessary by providing the insulating adhesive member, and the electronic component and the wiring are provided by providing the elastic layer. When the height difference occurs at the time of connection with the substrate, the height difference is absorbed by the contraction of the elastic layer, and the connection terminal and the elastic protrusion are connected to each other. Good connection between the electronic component and the wiring board can be maintained.

  Further, according to the micro LED display of the present invention, since the connection between the micro LED and the wiring board is connected by the connection element, the connection between the electronic component such as the micro LED and the wiring board can be improved. Can be kept. Thereby, the yield due to the connection failure of the micro LED in the manufacture of the micro LED display can be improved.

  Furthermore, according to the component mounting method of the present invention, by forming the board connection structure of the present invention, it is possible to maintain good connection between the electronic component and the wiring board.

1 is a plan view schematically showing an embodiment of a micro LED display according to the present invention. 1 is a cross-sectional view schematically illustrating an LED array substrate to which a substrate connection structure according to the present invention is applied. FIG. 2 is an enlarged sectional view of a main part of FIG. 1. FIG. 3 is a process diagram illustrating a component mounting method according to the present invention. FIG. 3 is a process diagram illustrating a component mounting method according to the present invention. 5 is a flowchart showing steps of a component mounting method according to the present invention. It is a flowchart explaining manufacture of a fluorescent light emitting layer array. It is a flowchart which shows the manufacturing process of a fluorescent light emitting layer array. It is a process drawing explaining an assembly process of an LED array substrate and a fluorescent light emitting layer array. It is explanatory drawing which shows the factor which causes a connection failure between a micro LED and a wiring board. It is explanatory drawing which shows the factor which causes a connection failure between a micro LED and a wiring board. FIG. 3 is an explanatory view showing a means for solving the problem of flatness of a sapphire substrate. It is explanatory drawing which shows the means which solves the problem of the height dispersion | variation in a micro LED. It is explanatory drawing which shows the means which solves the problem of the height variation in the connection terminal of a micro LED. It is explanatory drawing which shows the means which solves the problem of the height dispersion | variation in an elastic protrusion part. FIG. 4 is an explanatory view showing a means for solving the problem of flatness of a wiring board. It is sectional drawing which shows the modification of the board connection structure by this invention typically. It is a figure explaining a comparative example with respect to a substrate connection structure by the present invention. It is a figure explaining a comparative example with respect to a substrate connection structure by the present invention. FIG. 9 is a plan view of a modification of the micro LED display according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a plan view schematically showing an embodiment of a micro LED display according to the present invention. FIG. 2 is a cross-sectional view schematically showing an LED array substrate to which the substrate connection structure according to the present invention is applied. The micro LED display 100 includes an LED array substrate 1 and a fluorescent light emitting layer array 2. Note that the micro LED display is applicable to a flat display and a flexible display. When the micro LED display 100 is applied to, for example, a flat display, FIG. 1 omits illustration of, for example, a protective glass as another component.

  Note that the substrate connection structure according to the present invention can be applied even when the above-described factors causing the connection failure do not occur. Therefore, in order to make the description easy to understand, first, an application example in which a factor causing a connection failure does not occur will be described, and then an application example in a case where a factor causing a connection failure will occur will be described.

  The LED array substrate 1 includes a plurality of micro LEDs 3 arranged in a matrix as shown in FIG. 1 and a wiring substrate 4 including a wiring layer for driving the micro LEDs 3. The LED array substrate 1 can supply a video signal to each micro LED 3 from a drive circuit (not shown), and turn on and off each micro LED 3 individually to turn it off.

  The fluorescent light emitting layer array 2 includes a fluorescent light emitting layer 11 composed of a combination of red (11R), green (11G), and blue (11B) fluorescent dyes. Each fluorescent light emitting layer 11 is formed in the fluorescent light emitting layer array 2 at a position where, for example, a stripe-shaped opening 21 as shown in FIG. 1 is provided. Details of the fluorescent light emitting layer array 2 will be described later with reference to FIG.

  The micro LED 3 emits light in the ultraviolet to blue wavelength band, and is manufactured using gallium nitride (GaN) as a main material. The micro LED 3 is an example of an electronic component, and may be an LED that emits near-ultraviolet light having a wavelength of, for example, 200 nm to 380 nm, or may be an LED that emits blue light having a wavelength of, for example, 380 nm to 500 nm. The micro LED 3 is, for example, an LED having an outer dimension of 10 μm × 30 μm or less on the order of microns and good light emission.

  FIG. 2 shows a cross-sectional view of the LED array substrate 1 surrounded by a region R1 in the cross-sectional view taken along the line AA shown in FIG. The LED array substrate 1 includes a micro LED 3, a connection terminal 3a, a wiring substrate 4, an elastic layer 5, an electrode pad 6, an elastic protrusion 7, and an adhesive member 8. The connection between the micro LED 3 and the wiring board 4 is connected by a connection element S. The connection element S includes, for example, a connection terminal 3a, an elastic layer 5, an electrode pad 6, an elastic protrusion 7, and an adhesive member 8. The connection element S realizes mechanical connection and electrical connection between the micro LED 3 and the wiring board 4.

  The connection terminal 3a is an electrode provided on the micro LED 3, and is connected to the elastic projection 7 to achieve electrical conduction.

  The wiring substrate 4 is, for example, a flexible printed circuit (FPC), which is a film-shaped substrate including an insulating base film (for example, polyimide) and a wiring layer on which an electric circuit is formed. is there. The wiring board 4 shown in FIG. 2 has, for example, a multilayer flexible board structure in which polyimide layers 41 and wiring layers 42 are provided alternately. The via 43 has a structure of a through-hole, and the through-hole is provided with a wiring that is electrically connected, for example, by being filled with copper.

  The elastic layer 5 is provided on the wiring board 4 and contracts according to the pressing force when the micro LED 3 is pressed when connecting the micro LED 3 and the wiring board 4. Specifically, when connecting the micro LED 3 and the wiring board 4, the connection terminal 3 a and the elastic projection 7 are opposed to each other, and the gap between the corresponding connection terminal 3 a and the elastic projection 7 in the height direction is set. When a height difference occurs, the height difference is absorbed by the contraction of the elastic layer 5. The elastic layer 5 is formed of, for example, a silicone resin. However, the elastic layer 5 is not limited to the silicon resin, and may be, for example, a silicon-based material having silicon as a main component or a material having the same function as a silicone resin having a cushioning property. There may be. In the present embodiment, even when the height difference occurs, the height difference is absorbed, so that the connection terminal 3a and the elastic protrusion 7 can be connected well. When the elastic layer 5 is no longer pressed, a restoring force acts to return the contracted portion to the original state. Therefore, it is preferable to fix and connect the micro LED 3 and the wiring board 4 in a pressed state.

  The electrode pad 6 is for electrical connection, and is provided at a predetermined position on the elastic layer 5 corresponding to the connection terminal 3a provided on the micro LED 3. Specifically, the electrode pads 6 are provided on the elastic layer 5 corresponding to the connection terminals 3a provided on the surface opposite to the light extraction surface 3b of the micro LED 3 as shown in FIG. As shown in FIG. 2, in the micro LED 3, the connection terminal 3 a of the micro LED 3 and the electrode pad 6 are electrically connected via the conductive elastic protrusion 7 patterned and formed on the electrode pad 6. I have.

  The elastic projections 7 are provided on the electrode pads 6 to electrically connect the connection terminals 3 a and the electrode pads 6, and are connection terminals provided on the wiring board 4 side. The contact point between the connection terminal 3a and the elastic protrusion 7 is a contact (contact surface) of the connection terminal 3a, and a contact (contact surface) of the elastic protrusion 7.

  More specifically, the elastic projection 7 is, for example, a resin-made columnar projection 7b having a surface coated with a conductive film 7a of good conductivity such as gold or aluminum. However, the elastic protrusion 7 may be formed of a columnar protrusion formed of a conductive photoresist containing conductive fine particles such as silver added to a photoresist or a conductive photoresist containing a conductive polymer. FIG. 2 shows, as an example, a case in which a columnar projection 7b having a conductive film 7a adhered to the surface thereof is formed as the elastic projection 7, but the elastic projection 7 has a conductive property as described above. It may be formed of a photoresist.

  The bonding member 8 is provided in a columnar shape at a predetermined position around the elastic projection 7 and bonds (joins) the micro LED 3 to the elastic layer 5 and is made of a photosensitive adhesive having an insulating property. is there. Specifically, as shown in FIG. 2, the micro LED 3 is fixed on the elastic layer 5 by an adhesive via an adhesive member 8 provided around the electrode pad 6 of the wiring board 4. In this case, the adhesive member 8 is preferably a photosensitive adhesive that can be patterned by exposure and development. However, the adhesive member 8 may be an underfill agent or an ultraviolet curable adhesive. In short, since the bonding member 8 does not include metal particles having a size of several tens of microns such as, for example, an anisotropic conductive adhesive (ACA), it does not affect the connection element S.

  Here, the degree of hardness (Young's modulus) of the elastic layer 5, the elastic protrusion 7, and the adhesive member 8 is set as elastic protrusion 7> elastic layer 5> adhesive member 8. That is, the elastic projection 7 is harder than the elastic layer 5 and the adhesive member 8, and the elastic layer 5 is harder than the adhesive member 8. Next, the structure of the fluorescent light emitting layer array 2 will be described.

  FIG. 3 is an enlarged sectional view of a main part of FIG. FIG. 3 is an enlarged sectional view of a main part of the micro LED display 100 surrounded by a region R2 in the sectional view taken along the line BB shown in FIG. In FIG. 3, the LED array substrate 1 shown in FIG. 2 is illustrated in a simplified manner with the configuration of the micro LED 3, the connection element S, and the wiring substrate 4.

  The fluorescent light emitting layer array 2 is provided on the micro LED 3 arranged on the LED array substrate 1 as shown in FIG. The fluorescent light emitting layer array 2 is provided with a plurality of fluorescent light emitting layers 11 that respectively convert wavelengths into fluorescent light FL of a corresponding color by excitation light L emitted from the micro LED 3. Note that, for convenience of explanation, the excitation light L and the fluorescence FL are illustrated, and therefore, the LED array substrate 1 and the fluorescent light emitting layer array 2 are illustrated with a greater interval than in FIG. Have been.

  The fluorescent light emitting layer array 2 is provided on a transparent substrate 13 in a state where fluorescent light emitting layers 11 corresponding to each of red, green and blue are separated by a partition 12. Specifically, the fluorescent light emitting layer 11 is obtained by mixing and dispersing a fluorescent dye 14a having a large particle diameter of several tens of microns and a fluorescent dye 14b having a small particle diameter of several tens of nanometers in a resist film. It is. In the fluorescent light emitting layer array 2, the fluorescent light emitting layer 11 may be composed of only the fluorescent dye 14a having a large particle diameter. In this case, the filling rate of the fluorescent dye 14a is reduced, and the display of the excitation light L is reduced. Light leakage to the surface side increases.

  On the other hand, in the case of the fluorescent light emitting layer array 2, when the fluorescent light emitting layer 11 is formed only of the fluorescent dye 14 b having a small particle diameter, there is a problem that stability such as light resistance is poor. Therefore, in the present embodiment, as described above, it is preferable that the fluorescent light-emitting layer 11 be formed of a mixture in which the fluorescent dye 14a having a large particle diameter is more mixed than the fluorescent dye 14b having a small particle diameter. Accordingly, it is possible to suppress the leakage of the excitation light L to the display surface side and to improve the luminous efficiency.

  The mixing ratio of the fluorescent dyes 14 having different particle diameters is such that the fluorescent dye 14a having a large particle diameter is 50 to 90% by volume, and the fluorescent dye 14b having a small particle diameter is 10 to 50% by volume. It is desirable that the total of the fluorescent dye 14b and the fluorescent dye 14b be 100 Vol%.

  In the present embodiment, FIG. 1 shows a case where the fluorescent light emitting layers 11 corresponding to each color are provided in a stripe shape. However, the fluorescent light emitting layers 11 corresponding to each color may be provided corresponding to each micro LED 3 individually. .

  The partition walls 12 are provided so as to surround the fluorescent light emitting layers 11 corresponding to the respective colors, and separate the fluorescent light emitting layers 11 corresponding to the respective colors from each other. The partition 12 is formed of, for example, a transparent photosensitive resin. In the present embodiment, in order to increase the filling rate of the fluorescent dye 14 a having a large particle diameter in the fluorescent light emitting layer 11, a high aspect material that allows an aspect ratio of height to width of 3 or more is used for the partition 12. It is desirable to do. An example of such a high aspect material is SU-83000 photoresist manufactured by Nippon Kayaku Co., Ltd.

  As shown in FIG. 3, a metal film 15 is provided on the surface of the partition wall 12. The metal film 15 is for preventing the excitation light L and the fluorescent light FL from mixing with the fluorescent light FL in the fluorescent light emitting layer 11 of the adjacent other color through the partition 12. The fluorescent light FL emits light when the fluorescent light emitting layer 11 is excited by the excitation light L. The metal film 15 is formed with a thickness that can sufficiently block the excitation light L and the fluorescence FL. In this case, as the metal film 15, a thin film of aluminum, an aluminum alloy, or the like that easily reflects the excitation light L is preferable.

  As a result, the fluorescent light emitting layer array 2 reflects the excitation light L transmitted through the fluorescent light emitting layer 11 toward the partition 12 toward the inside of the fluorescent light emitting layer 11 by the metal film 15 such as aluminum. Can be used. Therefore, the luminous efficiency of the fluorescent light emitting layer 11 is improved. However, the thin film deposited on the surface of the partition 12 is not limited to the metal film 15 that reflects the excitation light L and the fluorescence FL, and may be a film that absorbs the excitation light L and the fluorescence FL.

  Next, a method of manufacturing the micro LED display 100 configured as described above will be described. The manufacturing method of the micro LED display 100 is roughly divided into a manufacturing process of the LED array substrate 1, a manufacturing process of the fluorescent light emitting layer array 2, and an assembling process of the LED array substrate 1 and the fluorescent light emitting layer array 2. In the manufacturing process of the LED array substrate 1, the component mounting method according to the present invention is applied. First, a method of mounting components of the micro LED 3 on the wiring board 4 for manufacturing the LED array substrate 1 will be described.

  4 and 5 are process diagrams illustrating a component mounting method according to the present invention. FIG. 6 is a flowchart showing the steps of the component mounting method according to the present invention.

  The component mounting method for mounting the micro LED 3 on the wiring board 4 is realized by the steps shown in FIGS. In this component mounting method, a plurality of micro LEDs 3 arranged in a matrix on one surface of a sapphire substrate 30 are positioned on a wiring substrate 4 including a wiring layer 42 for driving the micro LEDs 3, and the sapphire substrate 30 The micro LED 3 is mounted on the wiring board 4 by pressing the micro LED 3 from the other surface and fixing the micro LED 3 and then peeling off the micro LED 3 by a laser lift-off process. The sapphire substrate 30 is an example of a light transmissive wafer. In detail, as shown in FIG. 6, the component mounting method includes forming an elastic layer (step S11), forming an electrode pad and a columnar protrusion (step S12), forming a conductive elastic protrusion (step S13), and forming a via. Connection (step S14), formation of an adhesive member (step S15), alignment (step S16), pressing (step S17), bonding (step S18), and laser lift-off (step S19) are included. Hereinafter, description will be continued in this order.

  In the formation of the elastic layer (step S11), the elastic layer 5 is formed on the wiring board 4 prepared in advance. FIG. 4A illustrates a state in which the elastic layer 5 is formed. The wiring board 4 has the structure of the multilayer flexible board described above. In step S11, for example, a liquid silicon resin material is applied on the wiring board 4 to coat the entire upper surface of the wiring board 4 in a layered manner (for example, within a range of about 5 to 15 μm). The elastic layer 5 is formed by curing under an atmosphere.

  Next, formation of the electrode pads and columnar projections (Step S12) will be described. In step S12, an electrode pad 6 is formed on the elastic layer 5 corresponding to the connection terminal 3a of the micro LED 3. The electrode pad 6 is manufactured by a technique such as a photolithography process.

  Subsequently, in step S12, after applying a resist for a photo spacer on the entire upper surface of the elastic layer 5, the resist is exposed and developed using a photomask, and the elastic columnar projections 7b are formed on the electrode pads 6. Patterning is performed. FIG. 4B shows a state in which the electrode pad 6 and the columnar projection 7b are formed.

  Next, in the formation of the conductive elastic protrusion (step S13), a conductive film 7a of good conductivity such as gold or aluminum is formed on the columnar protrusion 7b by sputtering, vapor deposition, or the like, and the elastic protrusion 7 is formed. To form The elastic projection 7 includes a conductor film 7a and a columnar projection 7b. FIG. 4C illustrates a state in which the electrode pads 6 and the elastic protrusions 7 are formed.

  Specifically, in step S13, before forming the conductor film 7a, a resist layer is formed by photolithography on the peripheral portion except on the electrode pad 6, and after forming the conductor film 7a, the resist layer is formed with a solution. While dissolving the layer, the conductor film 7a on the resist layer is removed.

  As described above, the elastic protrusion 7 may be a columnar protrusion 7b formed of a conductive photoresist obtained by adding conductive fine particles such as silver to a photoresist or a conductive photoresist containing a conductive polymer. In this case, the elastic projections 7 are formed by applying a conductive photoresist to the entire surface of the upper surface of the wiring board 4 to a predetermined thickness, exposing it using a photomask, developing it, and developing it on the electrode pads 6. It is patterned and formed as a columnar projection 7b.

  As described above, since the elastic projections 7 are formed by, for example, applying a photolithography process, they can be easily formed even if the distance between the connection terminals 3a of the micro LED 3 is narrower than about 10 μm. Therefore, it is possible to manufacture the high-definition micro LED display 100.

  Next, in the via connection (step S14), the electrode pad 6 and the wiring layer 42 of the wiring board 4 are electrically connected, for example, by forming a hole using a laser and plating. In this case, by performing laser processing on a predetermined portion of the elastic layer 5 and the wiring board 4, the elastic layer 5 penetrates and reaches the via 43 (up to a predetermined wiring layer 42 in the wiring board 4). Through holes) are formed. The through holes are filled with metal by metal (for example, copper) plating, and can be electrically connected. Thereby, via connection is completed.

  FIG. 4D shows a state after the via connection has been made. Although one end of the via 43 is connected to the electrode pad 6 and the elastic protrusion 7 by the via connection, even if the electrode pad 6 sinks into the elastic layer 5 during pressing, the elastic protrusion 7 is still in contact with the electrode pad 6. It can be connected. Therefore, it is possible to avoid connection failure due to disconnection.

  Next, in the formation of the adhesive member (step S15), a photosensitive adhesive is applied in the state shown in FIG. The adhesive member 8 is formed by patterning such that the photosensitive adhesive in a predetermined region including the photosensitive adhesive is removed. In this case, the thickness of the applied photosensitive adhesive is set to be larger than the height including the electrode pad 6 and the elastic projection 7. FIG. 4E shows a state in which each adhesive member 8 is formed on the elastic layer 5.

  Next, in the alignment (step S16), in order to align the sapphire substrate 30 and the wiring substrate 4, when the sapphire substrate 30 and the wiring substrate 4 are bonded as shown in FIG. Positioning is performed so that the connection terminal 3a and the elastic projection 7 are connected to each other. FIG. 5A shows a state in which the connection terminal 3a and the elastic protrusion 7 are positioned.

  More specifically, in the positioning (step S16), when the sapphire substrate 30 and the wiring substrate 4 are bonded to each other, the position of the connection terminal 3a shown in FIG. Positioning is performed so that the (contact surface) and the contact (contact surface) of the elastic projection 7 are connected (contacted). In the sapphire substrate 30, the surface on which the micro LEDs 3 are arranged is referred to as a front surface, and the opposite surface is referred to as a back surface. In a later-described laser lift-off (step S19), the back surface is irradiated with laser.

  Next, in the pressing (step S17), the sapphire substrate 30 positioned in step S16 is lowered, and the surface of the sapphire substrate 30 is contacted with the contact of the connection terminal 3a and the contact of the elastic protrusion 7 so as to be connected. The wiring board 4 is bonded. Then, pressure is applied from the back surface of the sapphire substrate 30 to press the micro LED 3. FIG. 5B shows a state where the connection element S connects the sapphire substrate 30 and the wiring substrate 4. In FIG. 5B, for convenience of explanation, the pressure due to the pressing is suppressed to be lower than in the case of FIGS.

  In the bonding (step S18), the bonding member 8 is cured and the micro LED 3 and the elastic layer 5 on the wiring board 4 are bonded and fixed in the state shown in FIG. Thus, the micro LED 3 and the wiring board 4 are connected. Specifically, in step S18, the adhesive member 8 is cured by irradiating ultraviolet light (UV) with an ultraviolet light irradiation means (not shown). However, the adhesive member 8 may be a thermosetting type. Alternatively, a combination of ultraviolet curing and heat curing may be used. In the case of a combination type of ultraviolet curing and heat curing, in step S18, for example, it is preferable to perform temporary bonding by ultraviolet curing and then permanently bond by heat.

  In the laser lift-off (step S19), a laser beam of a line-shaped laser beam is irradiated on the back surface of the sapphire substrate 30 by targeting a group of LEDs to be irradiated with a mask pattern, thereby performing a laser lift-off process. I do. FIG. 5C shows a state in which the sapphire substrate 30 has been separated from the LED array substrate 1 by laser lift-off. Thus, the mounting of the micro LED 3 on the wiring board 4 is completed, and the LED array board 1 is manufactured.

Next, the manufacture of the fluorescent light emitting layer array 2 will be described.
FIG. 7 is a process chart for explaining the manufacture of the fluorescent light emitting layer array. FIG. 8 is a flowchart showing a manufacturing process of the fluorescent light emitting layer array. The manufacturing process of the fluorescent light emitting layer array includes forming an opening (step S21), forming a film (step S22), and forming a fluorescent light emitting layer (step S23).

  First, in the formation of the opening (step S21), as shown in FIG. 7A, a transparent photosensitive resin for the partition 12 is applied on the transparent substrate 13 and then exposed using a photomask. For example, a stripe-shaped opening 21 as shown in FIG. 1 is provided in correspondence with the formation position of each fluorescent light emitting layer 11 (see FIG. 7B). The transparent substrate 13 transmits at least light in the near ultraviolet to blue wavelength band, and is made of, for example, a glass substrate or a plastic substrate such as an acrylic resin. In the formation of the opening (step S21), a transparent partition wall 12 having a height-to-width aspect ratio of 3 or more is formed at a height of about 20 μm per minute. In this case, the photosensitive resin used is desirably a high aspect material such as SU-83000 manufactured by Nippon Kayaku Co., Ltd.

  Next, in film formation (step S22), a metal film 15 of, for example, aluminum or an aluminum alloy is formed to a predetermined thickness from the side of the partition wall 12 formed on the transparent substrate 13 by applying a film forming technique such as sputtering. Film. After the film formation, the metal film 15 attached to the transparent substrate 13 at the bottom of the opening 21 surrounded by the partition 12 is removed by laser irradiation.

  Alternatively, in the film formation (step S22), before the film formation, a resist or the like is applied to the surface of the transparent substrate 13 at the bottom of the opening 21 with a thickness of several μm by, for example, inkjet, and the metal film 15 is formed. Alternatively, the metal film 15 on the resist may be peeled and removed. In this case, a chemical solution that does not attack the resin of the partition wall 12 is selected as a resist solution used for removal.

  Next, in the formation of the fluorescent light emitting layer (step S23), as an example, a red fluorescent dye 14 is applied to the plurality of openings 21 corresponding to red as shown in FIG. The contained resist is applied by, for example, inkjet. The opening 21 is a region surrounded by the partition 12 as described above.

  Thereafter, in step S23, the red fluorescent light emitting layer 11R is formed by irradiating ultraviolet light to cure. Alternatively, in step S23, after applying a resist containing a red fluorescent dye 14 over the transparent substrate 13, the resist is exposed and developed using a photomask, and red is applied to the plurality of openings 21 corresponding to red. The fluorescent light emitting layer 11R may be formed. In this case, the resist is obtained by mixing and dispersing a fluorescent pigment 14a having a large particle diameter and a fluorescent pigment 14b having a small particle diameter. As described above, the mixing ratio of the fluorescent dye 14a having a large particle diameter is 50 to 90% by volume and the fluorescent dye 14b having a small particle diameter is 10 to 50% by volume as described above. The total amount is 100 Vol% with the dye 14b.

  Similarly, in step S23, a resist containing a green fluorescent dye 14 is applied to the plurality of openings 21 corresponding to green by, for example, inkjet, and then cured by irradiating ultraviolet rays to form a green fluorescent light emitting layer 11G. I do. Alternatively, in step S23, the above-described method of forming the red fluorescent light emitting layer 11R in the plurality of openings 21 corresponding to red is similarly applied to form the green fluorescent light emitting layer 11G in the plurality of openings 21 corresponding to green. May be.

  In the same manner, in step S23, a resist containing the blue fluorescent dye 14 is applied to the plurality of openings 21 corresponding to blue by, for example, ink jet, and then cured by irradiating ultraviolet light to form the blue fluorescent light emitting layer 11B. Form. Alternatively, in step S23, the above-described method of forming the red fluorescent light emitting layer 11R in the plurality of openings 21 corresponding to red is similarly applied to form the blue fluorescent light emitting layer 11B in the plurality of openings 21 corresponding to blue. May be.

  In step S23, it is preferable to provide an antireflection film for preventing reflection of external light on the display surface side of the fluorescent light emitting layer array 2. Further, in step S23, it is preferable to apply a black paint on the metal film 15 on the display surface side of the partition wall 12. By taking these measures, the reflection of external light on the display surface can be reduced, and the contrast can be improved.

  Subsequently, in the present embodiment, the micro LED display 100 is manufactured by assembling the LED array substrate 1 and the fluorescent light emitting layer array 2. FIG. 9 is a process diagram illustrating an assembly process of the LED array substrate and the fluorescent light emitting layer array. In FIG. 9, the LED array substrate 1 shown in FIG. 2 is illustrated in a simplified manner as in FIG.

  First, in the assembling process, the fluorescent light emitting layer array 2 is positioned on the LED array substrate 1 as shown in FIG. Specifically, using the alignment marks formed on the LED array substrate 1 and the alignment marks formed on the fluorescent light emitting layer array 2, the fluorescent light emitting layers 11 corresponding to each color of the fluorescent light emitting layer array 2 are used. The alignment is performed so as to be located on the corresponding micro LED 3 on the LED array substrate 1.

  In the assembly process, when the alignment between the LED array substrate 1 and the fluorescent light emitting layer array 2 is completed, as shown in FIG. 9B, the LED array substrate 1 and the fluorescent light emitting layer array 2 are joined by an adhesive (not shown). Thus, the micro LED display 100 is completed.

  Next, a specific example of the cause of the connection failure will be described, and subsequently, an application example of the component mounting method according to the present invention will be described.

  FIGS. 10 and 11 are explanatory diagrams showing factors that cause a connection failure between the micro LED and the wiring board. The illustration of the adhesive member is omitted for convenience of explanation. 10 and 11, a description will be given of a difference in height between the connection terminals and the elastic protrusions of the two micro LEDs 31 and 32.

(1) Flatness of Sapphire Substrate FIG. 10A is an explanatory diagram showing an example of a case where the flatness of the sapphire substrate is not uniform. Since the sapphire substrate 30 is warped, if the flatness is not uniform, the distance h1 between the connection terminal 31a of the micro LED 31 and the elastic projection 71 (the connection terminal on the wiring board 4 side) and the connection terminal 32a of the micro LED 32 The distance is not equal to the distance h2 from the elastic projection 72. Therefore, the difference (Δh = | h1−h2 |) indicating the degree of variation does not become zero, and a height difference (Δh> 0) occurs.

(2) Height of Micro LED FIG. 10B is an explanatory diagram showing an example of variation in height of the micro LED. If the heights of the micro LEDs 31 and 32 vary, the difference does not become zero, and a height difference occurs.

(3) Height of Connection Terminal of Micro LED FIG. 10C is an explanatory diagram showing an example of variation in height of the connection terminals 31a and 32a of the micro LED. If the heights of the connection terminals 31a and 32a vary, the difference does not become zero, and a height difference occurs.

(4) Height of Elastic Projection FIG. 11A is an explanatory diagram showing an example of variation in height of the elastic projections 71 and 72. If the heights of the elastic projections 71 and 72 vary, the difference does not become zero, and a height difference occurs.

(5) Flatness of Wiring Board FIG. 11B is an explanatory diagram showing an example of a case where the flatness of the wiring board is uneven. When the flatness of the wiring board 4 is not uniform, the difference does not become zero, so that a difference in elevation occurs.

  Although not shown, if there is a variation in the height of the bonding member 8 as well, the difference does not become zero, and a height difference occurs.

  As described above, when the above-described height difference as shown in FIGS. 10 and 11 occurs, when the sapphire substrate 30 and the wiring substrate 4 are bonded to each other, a problem that a connection failure occurs according to the height difference may occur. become. The substrate connection structure according to the present invention solves this problem as described below.

  FIG. 12 is an explanatory view showing a means for solving the problem of flatness of the sapphire substrate. FIG. 12 illustrates a case where the flatness of the sapphire substrate 30 is not uniform. (A) shows a state where the sapphire substrate 30 and the wiring substrate 4 are positioned. (B) shows a state after the sapphire substrate 30 and the wiring substrate 4 are bonded and pressed. (C) shows a state where the sapphire substrate 30 is peeled off by laser lift-off. The setting of the states (a) to (c) is the same in FIGS. 13 to 16.

  As shown in FIG. 12A, there is a height difference between the distance h1 between the connection terminal 31a and the elastic protrusion 71 and the distance h2 between the connection terminal 32a and the elastic protrusion 72. In the present embodiment, as an example, the sapphire substrate 30 is lowered in a state where the height difference is generated, and first stopped at a height at which the micro LED 31 and the upper surface of the adhesive member 8 are in contact with each other. Pressure from the back side of When pressure is applied, the adhesive member 8 contracts. This is because the elastic layer 5 is harder than the adhesive member 8 due to the degree of hardness described above. Subsequently, as shown in FIG. 12B, when the connection terminal 31a comes into contact with the elastic protrusion 71, a part of the elastic protrusion 71 of the micro LED 31 sinks into the elastic layer 5 according to the pressure. This is because the elastic projection 71 is harder than the elastic layer 5 due to the degree of hardness described above.

  On the other hand, the micro LED 32 is also pushed down by the pressing from the back surface of the sapphire substrate 30, but this micro LED 32 is just at the position in contact with the upper surface of the adhesive member 8, and the connection terminal 32 a and the elastic projection 72 are It is located to connect. This is an example, and a part of the elastic projection 72 may sink into the elastic layer 5 in response to the pressing. In short, it is only necessary that the connection terminal 31a and the elastic projection 71 and the connection terminal 32a and the elastic projection 72 are securely connected. That is, the elastic layer 5 absorbs the difference in height between the connection terminal 31a and the elastic protrusion 71 and between the connection terminal 32a and the elastic protrusion 72 due to the contraction of the elastic layer 5 so that each of the connection terminals And each elastic projection are connected. Absorbing the height difference means that each connection terminal and each elastic projection are connected to each other.

  Subsequently, as shown in FIG. 12C, the LED array substrate 1 is formed by a laser lift-off process. As a result, the LED array substrate 1 in which the height difference caused by the unevenness of the sapphire substrate is not formed is formed. The micro LED 31 and the micro LED 32 have a step in the height direction, but there is no particular problem from the viewpoint of LED light emission.

  FIG. 13 is an explanatory diagram showing a means for solving the problem of height variation in the micro LED. As shown in (a), if the heights of the micro LEDs 31 and 32 vary, the above-described height difference occurs. However, as shown in (b), when the micro LEDs 31 and 32 are pressed and connected on the wiring substrate 4 by pressing from the back surface of the sapphire substrate 30, the height difference is eliminated. Then, as shown in (c), the sapphire substrate 30 is removed by the laser lift-off process. Thereby, the LED array substrate 1 in which the height difference caused by the height variation of the micro LED is eliminated is formed. The micro LEDs 31 and 32 vary in the height direction, but there is no particular problem from the viewpoint of LED light emission.

  FIG. 14 is an explanatory diagram showing a means for solving the problem of height variation in connection terminals of micro LEDs. As shown in (a), if there is a variation in the height of the connection terminals 31a and 32a of the micro LED, the above-mentioned height difference occurs. However, as shown in (b), in the connected state, the height difference is eliminated. Then, as shown in (c), the sapphire substrate 30 is removed by the laser lift-off process. Thereby, the LED array substrate 1 in which the height difference caused by the variation in the height of the connection terminals 31a and 32a of the micro LED is eliminated is formed.

  FIG. 15 is an explanatory diagram showing a means for solving the problem of height variations in the elastic projections. As shown in (a), if the heights of the elastic projections 71 and 72 vary, the above-described height difference occurs. However, as shown in (b), in the connected state, the height difference is eliminated. Then, as shown in (c), the sapphire substrate 30 is removed by the laser lift-off process. Thereby, the LED array substrate 1 in which the height difference caused by the variation in the height of the elastic protrusion is eliminated is formed.

  FIG. 16 is an explanatory diagram showing a means for solving the problem of the flatness of the wiring board. As shown in (a), when the flatness of the wiring board 4 is not uniform, the above-described height difference occurs. However, as shown in (b), in the connected state, the height difference is eliminated. Then, as shown in (c), the sapphire substrate 30 is removed by the laser lift-off process. Thereby, the LED array substrate 1 in which the difference in elevation due to the unevenness of the flatness is eliminated is formed.

  Although not shown, even if the height of the adhesive member 8 varies, the height difference is eliminated in the connected state, and the sapphire substrate 30 is removed by the laser lift-off process. Is done. As a result, the LED array substrate 1 in which the height difference caused by the variation in the height of the adhesive member 8 is eliminated is formed.

  As described above, according to the board connection structure to which the component mounting method according to the present invention is applied, the height difference between the connection terminal and the elastic protrusion is absorbed by the contraction of the elastic layer, so that the connection terminal is connected to the elastic protrusion. It is possible to maintain a good connection between a minute electronic component such as a micro LED and a wiring board.

  In the above embodiment, the causes of the connection failure include the flatness of the sapphire substrate, the height of the micro LED, the height of the connection terminal of the micro LED, the height of the elastic protrusion, the flatness of the wiring board, and the height of the adhesive member. Although the above is described individually, even when a plurality of these factors are generated, the elastic layer absorbs a height difference caused by the plurality of factors, thereby making it difficult to cause the above-described connection failure. it can.

Next, a modified example of the substrate connection structure will be described.
FIG. 17 is a sectional view schematically showing a modified example of the substrate connection structure according to the present invention. In addition, about the structure same as the LED array board 1 shown in FIG. 2, description is abbreviate | omitted by attaching the same code | symbol. As shown in FIG. 17, the LED array substrate 1a to which the modification of the substrate connection structure according to the present invention is applied further includes an elastic layer 5a under the wiring substrate 4 for improving the degree of flatness of the wiring substrate 4 as shown in FIG. It is characterized by having. The elastic layer 5a is an example of another elastic layer.

  With such a configuration, for example, when the entire wiring substrate 4 is curved in a wavy manner as shown in FIG. 16, when pressed from the back surface of the sapphire substrate, the elastic layer 5 a Since it acts to suppress the curvature of the whole, an effect is obtained that the difference in elevation due to local variation is easily suppressed as a result. Further, the height difference caused by the above-mentioned plurality of factors can be absorbed by the elastic layer 5 and the elastic layer 5a.

Next, a comparative example for the substrate connection structure according to the present invention will be described. In the comparative example, a case where the sapphire substrate 30 and the wiring substrate 4 are actually bonded to each other when the height difference as described with reference to FIGS.
18 and 19 are diagrams illustrating a comparative example with respect to the substrate connection structure according to the present invention. This comparative example has a configuration in which the elastic layer 5 is not provided on the wiring board 4 as compared to the LED array substrate 1 shown in FIG. Further, illustration of the adhesive member is omitted for convenience of explanation.

  FIG. 18A shows a case where the flatness of the sapphire substrate 30 is not uniform. Even when the connection terminal 31a and the elastic projection 71 are connected, the gap between the connection terminal 32a and the elastic projection 72 is still large. (A difference indicating the degree of variation (Δh = h3)). In this state, if the difference (Δh = h3) indicating the degree of the variation exceeds a predetermined threshold value even when pressed from the back surface of the sapphire substrate 30, the height difference is absorbed only by the contraction of the elastic projection 71. Connection failure. The predetermined threshold is a value obtained by, for example, an experiment or a numerical simulation.

  FIG. 18B shows a case where the heights of the micro LEDs 31 and 32 vary, and even if the connection terminal 31a and the elastic projection 71 are connected, the connection between the connection terminal 32a and the elastic projection 72 is still present. There are intervals between them. In this state, if the difference (Δh = h3) exceeds a predetermined threshold even if the elastic member 71 is pressed from the back surface of the sapphire substrate 30, only the contraction of the elastic projection 71 does not absorb the height difference, and the connection failure is not caused. Will cause.

  FIG. 18C shows a case where the heights of the connection terminals 31a and 32a of the micro LED vary, and even if the connection terminal 31a and the elastic protrusion 71 are connected, the connection terminal 32a and the elastic protrusion still remain. There is an interval between the portion 72. In this state, if the difference (Δh = h3) exceeds a predetermined threshold even if the elastic member 71 is pressed from the back surface of the sapphire substrate 30, only the contraction of the elastic projection 71 does not absorb the height difference, and the connection failure is not caused. Will cause.

  FIG. 19A shows a case where the heights of the elastic protrusions 71 and 72 vary, and even if the connection terminal 31a and the elastic protrusion 71 are connected, the connection terminal 32a and the elastic protrusion 72 are still in contact. There is an interval between In this state, if the difference (Δh = h3) exceeds a predetermined threshold even if the elastic member 71 is pressed from the back surface of the sapphire substrate 30, only the contraction of the elastic projection 71 does not absorb the height difference, and the connection failure is not caused. Will cause.

  FIG. 19B shows a case where the flatness of the wiring board 4 is not uniform. Even if the connection terminal 32 a is connected to the elastic projection 72, the connection between the connection terminal 31 a and the elastic projection 71 is still present. There are intervals. In this state, if the difference (Δh = h3) exceeds a predetermined threshold value even when pressed from the back surface of the sapphire substrate 30, only the contraction of the elastic projection 72 does not absorb the difference in height, and a connection failure occurs. Will cause.

  As described above, when the substrate connection structure according to the present invention is compared with the substrate connection structure according to the comparative example, the substrate connection structure according to the present invention has an effect that the difference in height is absorbed and connection failure hardly occurs.

  That is, the board connection structure according to the present invention can absorb a height difference that cannot be absorbed even by the elastic projection. Therefore, even if there is a height difference that cannot be completely absorbed by the elastic projections, the board connection structure according to the present invention absorbs the height difference by contraction of the elastic layer, thereby connecting each connection terminal of each micro LED. It can be connected to the elastic projection.

  In the above embodiment, the fluorescent light emitting layer array 2 including the fluorescent light emitting layers 11 corresponding to each color is disposed on the LED array substrate 1 including the plurality of micro LEDs 3 that emits excitation light in the near ultraviolet to blue wavelength band. Although the micro LED display 100 having the structure has been described, the present invention is not limited to this, and the LED array substrate 1 is configured by arranging a plurality of micro LEDs 3 that individually emit red, green, and blue light, respectively, in a matrix. It may be provided. In this case, the fluorescent light emitting layer array 2 is unnecessary.

  FIG. 20 is a plan view of a modification of the micro LED display according to the present invention. The micro LED display 100a shown in FIG. 20 is a micro LED display capable of displaying a color image, and includes a plurality of micro LEDs 3 arranged in a matrix and a wiring board 4a including a wiring layer for driving the micro LEDs. Including the LED array substrate 1b. Therefore, the micro LED display 100a does not require the fluorescent light emitting layer array 2 shown in FIG. However, the plurality of micro LEDs 3 that individually emit red, green, and blue light, respectively, are provided on the LED array substrate 1b according to a predetermined arrangement so that a color image can be displayed.

  The micro LED 3 and the wiring board 4 are connected by the same connection element S as the LED array board 1 shown in FIG. The micro LED display 100a can be applied to a flat display or a flexible display, like the micro LED display 100. When the micro LED display 100a is applied to, for example, a flat display, FIG. 20 omits illustration of, for example, a protective glass as another component.

  As described above, according to the micro LED display 100a according to the present invention, similarly to the micro LED display 100, the connection between the micro LED 3 and the wiring board 4a can be kept good. Thereby, the yield due to the poor connection of the micro LED 3 in the manufacture of the micro LED display 100a can be improved.

  In the above embodiment, the micro LED display 100 according to the present invention has at least one of the micro LEDs 3 corresponding to red, green, and blue that emits excitation light in the ultraviolet to blue wavelength band. Alternatively, the fluorescent light emitting layer 11 for converting the wavelength of the excitation light into the wavelength of the corresponding color may be provided. In this case, the other micro LEDs 3 except the micro LED 3 that emits the excitation light emit light in the wavelength band of the corresponding color without requiring the fluorescent light emitting layer 11.

  In the above embodiment, the case where the electronic component is the micro LED 3 has been described. However, the present invention is not limited to this, and the electronic component may be, for example, a semiconductor component having the same size as the micro LED 3.

  Further, in the component mounting method of the above embodiment, when the sapphire substrate 30 and the wiring substrate 4 are positioned and bonded to each other, the lighting inspection of each micro LED 3 is performed, and a connection failure is found in the lighting inspection. Alternatively, the pressing may be performed until the connection failure caused by the height difference disappears. Thereby, the yield due to the connection failure of the micro LED can be further improved.

1, 1a, 1b: LED array substrate 2: Fluorescent light emitting layer array 3, 31, 32: Micro LED (electronic component)
3a, 31a, 32a connection terminal 4, 4a wiring board 5, 5a elastic layer 6 electrode pad 7, 71, 72 elastic projection 7a conductive film 7b columnar projection 8 adhesive member 11 fluorescent emission Layer S: Connection element 100, 100a: Micro LED display

Claims (8)

A board connection structure in which a plurality of electronic components are pressed and connected on a wiring board including a wiring layer for driving the electronic components,
An elastic layer provided on the wiring board and contracting according to the pressing force when the electronic component is pressed,
Corresponding to the connection terminals provided on each of the electronic components, provided on an electrode pad disposed on the elastic layer, a conductive elastic projection connected to the connection terminals,
An insulating adhesive member that is provided in a columnar shape at a predetermined position around the elastic protrusion and adheres the electronic component and the elastic layer,
Including
When connecting the electronic component and the wiring board, when a height difference occurs in a height direction interval between the corresponding connection terminal and the elastic protrusion, the height difference is absorbed by contraction of the elastic layer. An electronic component and the elastic layer are adhered to each other with the adhesive member, and the connection terminal and the elastic protrusion are connected to each other.   The elastic layer has a warp of a light-transmitting wafer used for a laser lift-off process for mounting the electronic component on the wiring board, a variation in height of each of the electronic components, and a thickness of each of the connection terminals. A height difference caused by at least one of a variation in height, a variation in height of each of the elastic protrusions, a degree of flatness of the wiring board, and a variation in height of each of the adhesive members. The substrate connecting structure according to claim 1, wherein the substrate connection structure absorbs the pressure by contracting the elastic layer.   3. The board connection structure according to claim 1, further comprising another elastic layer for improving a degree of flatness of the wiring board, below the wiring board.   The substrate connection structure according to claim 1, wherein the electronic component is a micro LED. A micro LED display capable of displaying a color image,
An LED array substrate including a plurality of micro LEDs arranged in a matrix and a wiring substrate including a wiring layer for driving the micro LEDs,
The connection between the micro LED and the wiring board,
An elastic layer provided on the wiring board and contracting according to the pressing force when the micro LED is pressed,
Corresponding to the connection terminal provided on each of the micro LEDs, a conductive elastic protrusion provided on the electrode pad disposed on the elastic layer and connected to the connection terminal;
Is provided in a columnar shape at a predetermined position around the elastic protrusion, and is connected by a connection element including an insulating adhesive member that adheres the micro LED and the elastic layer;
When connecting the micro LED and the wiring board, if a height difference occurs in a height direction interval between the corresponding connection terminal and the elastic projection, the height difference is absorbed by contraction of the elastic layer. A micro LED display, wherein the micro LED and the elastic layer are adhered to each other with the adhesive member, and the connection terminal is connected to the elastic projection.   On the LED array substrate, a fluorescent light emitting layer array having a plurality of fluorescent light emitting layers that are each excited by excitation light emitted from the micro LED to convert the wavelength to fluorescence of a corresponding color is further provided. The micro LED display according to claim 5, characterized in that: A plurality of electronic components arranged in a matrix on one surface of a light-transmitting wafer are positioned on a wiring board including a wiring layer for driving the electronic components, and the electronic components are positioned from the other surface of the wafer. A component mounting method of mounting the electronic component on the wiring board by pressing a component, fixing the electronic component, and peeling the wafer by a laser lift-off process,
Forming an elastic layer on the wiring board, which contracts in response to the pressure when the electronic component is pressed;
Patterning a conductive elastic protrusion on an electrode pad disposed on the elastic layer corresponding to the connection terminal of the electronic component;
Making a via connection between the connection terminal of the electronic component and the wiring layer of the wiring board;
Exposure and development after applying an insulating adhesive on the elastic layer, forming a columnar adhesive member at a predetermined position around the electrode pad,
A step of positioning and pressing the electronic component on the wiring board,
Curing the adhesive member and bonding the electronic component to the wiring board;
Removing the wafer by the laser lift-off process;
A component mounting method comprising:   The method according to claim 7, wherein the electronic component is a micro LED.