Transfer substrate

Abstract

Provided is a transfer substrate for improving the performance of an electronic device provided with a plurality of elements. A transfer substrate (70) is provided with: a support substrate (71); an adhesive resin layer (72) which is continuously provided on one surface of the support substrate (71) and has a plurality of holding regions for adhesively holding the elements (20); and a cover film (73) which is provided on the surface of the adhesive resin layer (72) on the opposite side from the support substrate (71) so as to cover a region outside the holding region of the adhesive resin layer (72), and which has a lower adhesive force on the surface than the adhesive force of the adhesive resin layer (72).

Description

Technical Field

[0001] The present disclosure relates to a transfer substrate. Background Art

[0002] There is a method for manufacturing an electronic device for mounting electronic components (elements) on a plurality of electrodes arranged on a circuit substrate. For example, Japanese Patent Publication No. 2022-158612 (Patent Document 1) describes a method for mounting an electronic component in which a light-emitting element provided on a sapphire substrate is mounted on a terminal portion of a circuit substrate. In addition, for example, Japanese Patent Publication No. 2021-5632 (Patent Document 2) describes a transfer substrate having a plurality of protrusions protruding from a first surface of an elastomer as a transfer substrate for transferring micro LED elements onto a circuit substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-158612

[0006] Patent Document 2: Japanese Patent Application Publication No. 2021-5632 Utility Model Content

[0007] Technical problems to be solved by utility models

[0008] As described above, sometimes, multiple components are mounted on a circuit substrate at once by bonding and holding the components through the adhesive resin layer of the transfer substrate to manufacture an electronic device. When multiple components are mounted on a circuit substrate in this way, if, for example, warping occurs on the circuit substrate or the transfer substrate, the transfer substrate needs to be strongly pressed against the circuit substrate. As a result, the adhesive resin layer is sometimes fixed to the circuit substrate side.

[0009] An object of the present disclosure is to provide a technology for improving the performance of an electronic device including a plurality of elements.

[0010] Means for solving technical problems

[0011] A transfer substrate in one embodiment of the present invention comprises: a supporting substrate; an adhesive resin layer continuously provided on a surface of the supporting substrate for bonding and retaining components in a plurality of retaining areas; and a covering film provided on a surface of the adhesive resin layer on the opposite side of the supporting substrate so as to cover an area outside the retaining area of ​​the adhesive resin layer, the adhesive force of the surface being weaker than the adhesive force of the adhesive resin layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1This is a plan view showing a configuration example of a micro LED display device as one embodiment of an electronic device.

[0013] Figure 2 Yes means Figure 1 A circuit diagram showing an example of the configuration of a circuit around a pixel shown.

[0014] Figure 3 It means that they are configured in Figure 1 FIG. 1 is a perspective enlarged plan view of an example of a peripheral structure of LED elements of a plurality of pixels of a display device shown.

[0015] Figure 4 It is along Figure 3 Enlarged cross-sectional view of line A-A.

[0016] Figure 5 It means removed Figure 3 An enlarged plan view of the substrate structure showing the state of the LED element.

[0017] Figure 6 It is an explanatory diagram showing an example of a process flow of a method for manufacturing a display device as one embodiment of the electronic device.

[0018] Figure 7 It is along Figure 5 An enlarged cross-sectional view of the B-B line.

[0019] Figure 8 is Figure 6 The figure shows a perspective view of a transfer substrate prepared in the transfer substrate preparing step.

[0020] Fig. 9 Yes means Figure 8 An enlarged top view of a portion of the transfer substrate.

[0021] Fig.10 It is along Fig. 9 Enlarged cross-sectional view of the C-C line.

[0022] Fig.11 Yes Description Figure 6 A diagram showing the component holding process.

[0023] Fig.12 Yes Description Figure 6 A diagram showing the component pressing process.

[0024] Fig.13A Yes Description Figure 6 A diagram showing the component pressing process.

[0025] Fig. 13B Yes Description Figure 6 A diagram showing the component pressing process.

[0026] Fig. 13C Yes Description Figure 6 A diagram showing the component pressing process.

[0027] Fig.14 Yes Description Figure 6 A diagram showing the component pressing process.

[0028] Fig.15 Yes Description Figure 6 A diagram showing the laser irradiation process.

[0029] Fig.16 Yes Description Figure 6 A diagram showing the component peeling process.

[0030] Description of Reference Numerals

[0031] 5 Control circuit

[0032] 6. Driving Circuit

[0033] 10 Circuit board

[0034] 10f, 10b

[0035] 11, 12, 13, 14 inorganic insulating layer

[0036] 14H opening

[0037] 20LED components (light-emitting components, components)

[0038] 21 electrodes

[0039] 21EA Anode Electrode

[0040] 21EK cathode electrode

[0041] 31, 32, VL, VSL wiring

[0042] 33 Bump electrode

[0043] 41 Insulation layer

[0044] 50 Semiconductor layer

[0045] 70 Transfer substrate

[0046] 71 Support base plate

[0047] 72 Adhesive resin layer

[0048] 72f face

[0049] 73 Covering film

[0050] 73a Opening

[0051] 74 Keep Area

[0052] 80 Gap

[0053] DSP1 display device (electronic device)

[0054] ED Drain Electrode

[0055] EG Gate electrode

[0056] ES Source electrode

[0057] GL Scan signal line

[0058] Gs control signal

[0059] LXP wiring cross section

[0060] LZ laser (laser light)

[0061] LZS Laser Source

[0062] PFA Surrounding Area

[0063] PIX

[0064] PVS reference potential (fixed potential)

[0065] SUB1 substrate structure

[0066] SW Switching Element

[0067] Vsg Image Signal DETAILED DESCRIPTION

[0068] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the disclosure is only an example. Appropriate changes that can be easily thought of by those skilled in the art while maintaining the main purpose of the utility model are of course included in the scope of the present invention. In addition, in order to explain more clearly, the drawings sometimes schematically indicate the width, thickness, shape, etc. of each part compared to the actual method, but this is only an example and does not limit the interpretation of the present invention. In addition, in this specification and each figure, the same or related figure marks are sometimes marked for the same elements as those described in the drawings that have appeared, and the detailed description is appropriately omitted.

[0069] In the following embodiments, a micro LED display device equipped with a plurality of micro LED elements is described as an example of an electronic device equipped with a plurality of electronic components. In addition, the micro LED display device may be simply referred to as a display device.

[0070] <Electronic devices>

[0071] First, a configuration example of a micro LED display device as an electronic device according to the present embodiment will be described. Figure 1 1 is a top view showing a configuration example of a micro LED display device as one embodiment of an electronic device. Figure 1 In FIG. 1 , the boundary between the display area DA and the peripheral area PFA, the control circuit 5 , the drive circuit 6 , and the plurality of pixels PIX are respectively indicated by two-dot chain lines. Figure 2 Yes means Figure 1 A circuit diagram showing an example of the configuration of a circuit around a pixel shown.

[0072] like Figure 1 As shown, the display device DSP1 of this embodiment includes a display area DA, a peripheral area PFA surrounding the display area DA in a frame shape, and a plurality of pixels PIX arranged in a matrix in the display area DA. In addition, the display device DSP1 includes a circuit substrate 10 having a rectangular planar shape, a control circuit 5 formed on the circuit substrate 10, and a drive circuit 6 formed on the circuit substrate 10. The circuit substrate 10 is made of glass or resin.

[0073] The control circuit 5 is a control circuit for controlling the driving of the display function of the display device DSP1. For example, the control circuit 5 is a driver IC (Integrated Circuit) mounted on the circuit board 10. Figure 1 In the example shown, the control circuit 5 is arranged along one short side among the four sides of the circuit substrate 10, that is, along the X direction shown in the figure. In the following description, the short side direction of the circuit substrate 10 is sometimes referred to as the X direction, the long side direction of the circuit substrate 10 is sometimes referred to as the Y direction, and the thickness direction of the circuit substrate 10 is sometimes referred to as the Z direction.

[0074] In the present embodiment, the control circuit 5 includes a wiring (video signal wiring) VL (see Figure 2 However, the position and structure of the control circuit 5 are not limited to Figure 1 There are various variations of the examples shown. Figure 1 In the embodiment, a wiring substrate such as a flexible substrate is sometimes connected to the position shown as the control circuit 5, and the above-mentioned driver IC is mounted on the wiring substrate. In addition, for example, a signal line driving circuit that drives the wiring VL may be formed separately from the control circuit 5.

[0075] The driving circuit 6 includes a scanning signal line GL (see FIG. Figure 2). In addition, the drive circuit 6 includes a circuit for supplying a reference potential to the LED elements respectively mounted on the plurality of pixels PIX. The drive circuit 6 drives the plurality of scanning signal lines GL based on a control signal from the control circuit 5. Figure 1 In the example shown, the drive circuit 6 is disposed along two long sides of the four sides of the circuit substrate 10. However, the position and configuration of the drive circuit 6 are not limited to the above. Figure 1 There are various variations of the examples shown. Figure 1 In the embodiment, a wiring substrate such as a flexible substrate may be connected to the position shown as the control circuit 5, and the drive circuit 6 may be mounted on the wiring substrate.

[0076] Next, use Figure 2 An example of the circuit configuration of the pixel PIX is described below. Figure 2 The diagram shows four pixels PIX, but Figure 1 The plurality of pixels PIX shown in the figure have Figure 2 The same circuit as the pixel PIX shown in the figure. Hereinafter, the circuit including the switch element SW and the LED element 20 of the pixel PIX is sometimes referred to as a pixel circuit. The pixel circuit is a circuit that is controlled by the control circuit 5 (see Figure 1 ) is a circuit in which a voltage signal type is used to control the light-emitting state of the LED element 20 using the image signal Vsg supplied thereto.

[0077] like Figure 2 As shown, each pixel PIX includes an LED element 20. The LED element 20 is the micro light emitting diode described above. The LED element 20 has an anode electrode 21EA and a cathode electrode 21EK. The cathode electrode 21EK of the LED element 20 is connected to the wiring VSL to which the reference potential (fixed potential) PVS is supplied. The anode electrode 21EA of the LED element 20 is electrically connected to the drain electrode ED of the switch element SW via the wiring 31.

[0078] Each pixel PIX includes a switch element SW. The switch element SW is a transistor that controls the connection state (on or off state) between the pixel circuit and the wiring VL in response to the control signal Gs. The switch element SW is, for example, a thin film transistor. When the switch element SW is in the on state, the video signal Vsg is input from the wiring VL to the pixel circuit.

[0079] The drive circuit 6 includes a shift register circuit, an output buffer circuit, etc. (not shown). The drive circuit 6 is based on the control circuit 5 (see Figure 1 ) transmits the horizontal scan start pulse and outputs a pulse, and outputs a control signal Gs.

[0080] The plurality of scanning signal lines GL extend in the X direction. The scanning signal line GL is connected to the gate electrode EG of the switch element SW. When the control signal Gs is supplied to the scanning signal line GL, the switch element SW is turned on, and the video signal Vsg is supplied to the LED element 20 .

[0081] <LED element peripheral structure>

[0082] Next, configure the Figure 1 The peripheral structure of the LED element 20 of the plurality of pixels PIX shown will be described. Figure 3 It means that they are configured in Figure 1 A perspective enlarged top view of an example of the peripheral structure of LED elements of a plurality of pixels of the display device shown. Figure 3 In, omitted Figure 4 The inorganic insulating layer 14 is shown. Figure 3 In FIG. 1 , the outlines of the semiconductor layer, the electrode, and the scanning signal line are indicated by dotted lines. Figure 4 It is along Figure 3 Enlarged cross-sectional view of line A-A. Figure 5 It means removed Figure 3 An enlarged plan view of the substrate structure showing the state of the LED element.

[0083] like Figure 3 As shown, the display device DSP1 has a plurality of pixels PIX (in Figure 3 In the example shown, the pixels are PIX1, PIX2, and PIX3. Each of the plurality of pixels PIX includes a switch element SW, an LED element (light emitting element) 20, a wiring 31, and a wiring 32. In addition, each of the pixels PIX1, PIX2, and PIX3 includes an LED element 20 that emits visible light of any one color of red, green, and blue, and a switch element SW that drives the LED element 20 is formed.

[0084] When the LED elements 20 of the pixels PIX1, PIX2, and PIX3 emit the above-mentioned visible light of each color, color display can be performed on the display device DSP1 by controlling the output and timing of the visible light emitted from the LED elements 20 of the pixels PIX1, PIX2, and PIX3. In this way, when a plurality of pixels PIX emitting visible light of different colors are combined, the pixels PIX for each color are sometimes referred to as sub-pixels, and the group of the plurality of pixels PIX is sometimes referred to as a pixel.

[0085] The wiring 31 is electrically connected to the drain electrode ED of the switching element SW and the anode electrode 21EA of the LED element 20. The wiring 32 is connected to the source electrode ES of the switching element SW. Figure 3In the example shown, the wiring 32 has a bent structure, one end of which is connected to the source electrode ES of the switching element SW, and the other end of which is connected to the wiring VL. The scanning signal line GL is used as the gate electrode EG of the switching element SW.

[0086] The display device DSP1 further includes a wiring VL and a wiring VSL. The wiring VL extends over a plurality of pixels PIX along the Y direction (see Figure 2 ) and is electrically connected to the wiring 32. The wiring VSL extends along the Y direction ( Figure 3 The wiring VL and the wiring VSL extend over the plurality of pixels PIX in the X direction (which is orthogonal to the X direction) and are electrically connected to the cathode electrode 21EK of the LED element 20. Figure 3 The wiring intersection LXP shown crosses the wiring VL and the wiring VSL via the insulating layer 41. Since the insulating layer 41 is interposed between the wiring VL and the wiring VSL, the wiring VL and the wiring VSL are electrically separated.

[0087] like Figure 4 As shown, the display device DSP1 is an electronic device having an LED element 20 and a substrate structure SUB1. The substrate structure SUB1 is configured to include: a circuit substrate 10 made of glass or resin, and a plurality of insulating layers stacked on the circuit substrate 10. The plurality of insulating layers of the substrate structure SUB1 include an inorganic insulating layer 11, an inorganic insulating layer 12, an inorganic insulating layer 13, and an inorganic insulating layer 14 stacked on the circuit substrate 10. The circuit substrate 10 has a surface 10f and a surface 10b on the opposite side of the surface 10f. The inorganic insulating layers 11, 12, 13, and 14 are stacked on the surface 10f of the circuit substrate 10, respectively.

[0088] The switch element SW includes an inorganic insulating layer 12 formed on a circuit substrate 10, a semiconductor layer 50 formed on the inorganic insulating layer 12, a drain electrode ED connected to a drain region of the semiconductor layer 50, a source electrode ES connected to a source region of the semiconductor layer 50, and an inorganic insulating layer 13 covering the semiconductor layer 50. The wiring 31 and the wiring 32 are laminated films of a conductor layer composed of, for example, titanium or a titanium alloy and a conductor layer composed of aluminum or an aluminum alloy, respectively. A laminated film in which an aluminum layer is sandwiched between titanium layers is called a TAT laminated film.

[0089] Figure 4 The example shown is an example of a bottom gate method in which the gate electrode EG is located between the semiconductor layer 50 and the circuit substrate 10. In the case of the bottom gate method, the portion of the inorganic insulating layer 12 located between the gate electrode EG and the semiconductor layer 50 functions as a gate insulating layer. In addition, the inorganic insulating layer 12 also functions as a base layer for forming the semiconductor layer 50. In addition, the position of the gate electrode EG is not limited to Figure 4 The example shown may also be a top gate method, for example.

[0090] The material constituting each of the inorganic insulating layers 11, 12, 13, and 14 is not particularly limited, but examples thereof include silicon oxide (SiO 2 ), silicon nitride (SiN), etc. In addition, the semiconductor layer 50 is, for example, a semiconductor film in which a P-type or N-type conductivity-type impurity is doped in a silicon film made of silicon.

[0091] The source electrode ES and the drain electrode ED are contact plugs for making electrical contact with either the source region or the drain region of the semiconductor layer 50. As a material of the contact plug, for example, tungsten can be cited. Figure 4 In a modification example, contact holes exposing the source region and the drain region of the semiconductor layer 50 are sometimes formed in the inorganic insulating layer 13, and a portion of the wiring 31 and a portion of the wiring 32 are respectively buried in the contact holes. In this case, the portions of the wiring 31 and the wiring 32 buried in the contact holes are in contact with the semiconductor layer 50, and the contact interfaces between the wiring 31 and the wiring 32 and the semiconductor layer 50 can be regarded as the drain electrode ED and the source electrode ES.

[0092] In addition, if Figure 5 As shown in FIG. 1 , the substrate structure SUB1 includes a plurality of bump electrodes 33 that are regularly arranged in a plan view. The bump electrodes 33 are used to form a plurality of bump electrodes 33 on the circuit substrate 10 (see FIG. 1 ). Figure 4 ) is mounted on the terminal of the electronic component. In the case of this embodiment, the bump electrode 33 is used to mount Figure 4 Therefore, the plurality of bump electrodes 33 are provided on the LED element 20 (see Figure 3 ) are arranged adjacent to each other in the mounting planned region. One of the two bump electrodes 33 is connected to the anode electrode 21EA of the LED element 20, and the other is connected to the cathode electrode 21EK of the LED element 20.

[0093] like Figure 4 As shown in FIG. 1 , the bump electrode 33 is connected to the wiring 31 at a position overlapping with the opening 14H formed in the inorganic insulating layer 14, and protrudes from the inorganic insulating layer 14. In addition, the bump electrode 33 is composed of, for example, a solder containing tin. Alternatively, the bump electrode 33 is sometimes a laminate of a metal layer and a solder layer, and the metal layer is composed of a metal material such as copper having a higher conductivity than the solder.

[0094] <Method for manufacturing electronic device>

[0095] Next, Figure 3 The method for manufacturing the electronic device of the present embodiment will be described using the method for manufacturing the display device DSP1 shown as a representative example. Figure 6It is an explanatory diagram showing an example of a process flow of a method for manufacturing a display device as one embodiment of the electronic device.

[0096] like Figure 6 As shown, the method for manufacturing an electronic device of the present embodiment includes a substrate structure preparation step S1 , a transfer substrate preparation step S2 , a component holding step S3 , a component pressing step S4 , a laser irradiation step S5 , and a component peeling step S6 .

[0097] <Substrate structure preparation process>

[0098] exist Figure 6 In the substrate structure preparation step S1 shown in FIG. Figure 7 The substrate structure SUB1 is shown. Figure 7 The figure is used to explain the substrate structure preparation process, and is along the Figure 5 In the substrate structure preparation step S1, as shown in FIG. Figure 7 As shown, a substrate structure SUB1 is prepared, which includes a circuit substrate 10 made of glass or resin, a wiring 31 formed on the circuit substrate 10, and an inorganic insulating layer 14 covering the wiring 31. The inorganic insulating layer 11, the inorganic insulating layer 12, the inorganic insulating layer 13, and the inorganic insulating layer 14 are stacked on the circuit substrate 10, and the wiring 31 is arranged between the inorganic insulating layer 13 and the inorganic insulating layer 14. Most of the substrate structure SUB1 is covered by the inorganic insulating layer 14. In the inorganic insulating layer 14, an opening 14H is formed at a position overlapping with the wiring 31 and a position overlapping with the wiring VSL. At the bottom of the opening 14H, the wiring 31 and the wiring VSL are exposed from the inorganic insulating layer 14.

[0099] The plurality of bump electrodes 33 are respectively embedded in the openings 14H and connected to the wiring 31 or the wiring VSL at the bottom of the openings 14H. Figure 5 As shown, when the substrate structure SUB1 is viewed from above, the plurality of bump electrodes 33 are respectively mounted on the electronic components ( Figure 3 The LED elements 20 shown are regularly arranged in a predetermined area.

[0100] like Figure 7 As shown in FIG. 1 , the bump electrode 33 is formed to protrude above the inorganic insulating layer 14. As described above, a portion of the wiring 31 and a portion of the wiring VSL are partially exposed from the inorganic insulating layer 14 in the opening 14H, so the bump electrode 33 can be selectively formed by, for example, electroplating. In addition, in order to increase the protruding height of the bump electrode 33, the bump electrode 33 is sometimes formed using a resist film.

[0101] <Substrate preparation process for transfer>

[0102] exist Figure 6 In the transfer substrate preparation step S2 shown in FIG. Figures 8 to 10 The transfer substrate shown. Figure 8 This is a perspective view of a transfer substrate prepared in the transfer substrate preparing step.

[0103] Fig. 9 is an enlarged top view showing a portion of the transfer substrate, Fig.10 It is along Fig. 9 Enlarged cross-sectional view of the C-C line.

[0104] Figures 8 to 10 The transfer substrate 70 shown includes a support substrate 71, an adhesive resin layer 72 provided on one surface of the support substrate 71, and a cover film 73 provided on the surface of the adhesive resin layer 72 on the opposite side of the support substrate 71. The support substrate 71 is a substrate for ensuring the rigidity of the transfer substrate 70, and its plane shape is substantially rectangular. The support substrate 71 is, for example, a synthetic substrate having silicon oxide as a main component, such as quartz or glass. In addition, as the transfer substrate 70, a plane shape of a rectangle is illustrated, but this is only an example, and the shape of the transfer substrate 70 is not particularly limited.

[0105] The adhesive resin layer 72 is a layer for bonding and holding a plurality of LED elements 20 in the element holding step S3 described later, and is continuously provided on the surface of the support substrate 71. More specifically, the resin adhesive layer 72 (transfer substrate 70) has a plurality of holding areas 74 in a matrix shape to which the LED elements 20 are bonded and held, respectively. The adhesive resin layer 72 is provided over a range including these plurality of holding areas 74 on the support substrate 71.

[0106] The number of holding regions 74 included in the adhesive resin layer 72 (transfer substrate 70 ) is not particularly limited, and may be appropriately determined based on, for example, the number of LED elements 20 included in the display device DSP1 .

[0107] The adhesive resin layer 72 is formed of an adhesive resin material capable of bonding and holding the LED element 20, and has a surface 72f (see Fig.10 ) has an adhesive force capable of bonding and holding the LED element 20. However, the LED element 20 bonded and held by the adhesive resin layer 72 is peeled off from the adhesive resin layer 72 after being mounted on the substrate structure SUB1. Therefore, it is necessary to take this into consideration and appropriately adjust the adhesive force of the adhesive resin layer 72. The thickness of the adhesive resin layer 72 is not particularly limited, but is preferably about several tens of μm, and in the present embodiment, is set to about 20 μm.

[0108] Examples of the resin material used in the adhesive resin layer 72 include acrylic resins, polyester resins, vinyl chloride-vinyl acetate copolymer resins, ethylene-acrylate copolymer resins, ethylene-methacrylate copolymer resins, polyamide resins, polyolefin resins, chlorinated polyolefin resins, epoxy resins, and polyurethane resins. Of course, the resin material used for the adhesive resin layer 72 is not limited to these.

[0109] The covering film 73 is a film for preventing the adhesive resin layer 72 from adhering to the substrate structure SUB1 including the circuit substrate 10 in the element pressing step S4 described later, and the adhesive force of the surface of the covering film 73 is lower than the adhesive force of the surface of the adhesive resin layer 72. In other words, the covering film 73 is formed of a material with lower adhesiveness than the resin material forming the adhesive resin layer 72. As described above, the adhesive resin layer 72 has an adhesive force capable of adhering to the LED element 20 on the surface 72f. As a result, the adhesive resin layer 72 has an adhesive force on the surface 72f to adhere to the substrate structure SUB1. The adhesive force of the surface of the covering film 73 is lower than the adhesive force of the surface 72f of the adhesive resin layer 72.

[0110] In addition, it is preferred that the adhesive force of the surface of the covering film 73 is as low as possible, and it is particularly preferred that the surface has no adhesive force. That is, the covering film 73 whose surface adhesive force is lower than that of the adhesive resin layer 72 includes not only the case where the surface has a film with an adhesive force lower than that of the adhesive resin layer 72, but also the case where the surface has no adhesive force.

[0111] The covering film 73 is provided on a surface of one side of the adhesive resin layer 72, in this example, the surface 72f of the adhesive resin layer 72 on the side opposite to the support substrate 71. In addition, the covering film 73 is provided to cover the area outside the holding area 74 in the surface 72f of the adhesive resin layer 72. As an example, the covering film 73 is provided to surround the periphery of each holding area 74. In other words, the covering film 73 is provided to cover substantially the entire surface of the surface 72f of the adhesive resin layer 72, except for the portion corresponding to each holding area 74. In other words, the covering film 73 is provided to cover substantially the entire surface of the surface 72f of the adhesive resin layer 72, and has an opening 73a at a position corresponding to each holding area 74.

[0112] The opening shape (planar shape) of the opening portion 73a is not particularly limited, but is preferably an opening shape along the planar shape of the holding region 74. Each holding region 74 is a region for bonding and holding the LED element 20. As an example, the shape of the holding region 74 is consistent with the planar shape of the LED element 20. Therefore, it can be said that the opening portion 73a is preferably a shape along the planar shape of the LED element 20. In the present embodiment, the planar shape of the LED element 20 is a rectangle, so the shape of each holding region 74 is also a rectangle. Therefore, the opening shape of the opening portion 73a is also preferably formed into a rectangle along the shape of the holding region 74.

[0113] Considering the positioning accuracy when the LED element 20 is bonded and held by the adhesive resin layer 72, it is preferable to form the opening 73a of the cover film 73 slightly larger than each holding area 74. For example, when the planar shape of the LED element 20 (the shape of the holding area 74) is a rectangle of about 20 to 30 μm square, it is preferable that the length of one side of the opening 73a is about 2 to 5 μm longer than the length of one side of the holding area 74. In other words, for example, Fig. 9 As shown, it is preferred that a gap 80 exists around the holding region 74 and between the holding region 74 and the adhesive resin layer 72 , and the gap 80 has a predetermined width W1 of about 1 to 2.5 μm.

[0114] In addition, the cover film 73 is composed of a metal thin film such as copper or aluminum. However, the material of the cover film 73 is not limited to a metal material. As the material of the cover film 73, an inorganic material is preferably used, but any material can be used as long as it can suppress the adhesion of the adhesive resin layer 72 to the substrate structure SUB1 and can withstand the heat received in the laser irradiation step described later. In addition, the material of the cover film 73 is preferably a material that does not adhere to the substrate structure SUB1, especially a material that does not have adhesiveness.

[0115] The method for forming the cover film 73 composed of the metal thin film is not particularly limited, but examples thereof include a vapor deposition method, a sputtering method, etc. Furthermore, for example, the cover film 73 may be formed by forming a metal thin film on a substrate different from the transfer substrate 70 and then transferring the metal thin film onto the adhesive resin layer 72.

[0116] <Component holding process>

[0117] Next, in Figure 6 In the component holding step S3 shown in FIG. Fig.11 As shown, the LED element 20 is bonded and held by the adhesive resin layer 72 in each of the plurality of holding regions 74 of the transfer substrate 70 . Fig.11 is a diagram illustrating a component holding process. More specifically, Fig.11 It means in Fig.10An enlarged cross-sectional view showing a state in which an LED element is held by an adhesive resin layer in each holding region of the transfer substrate shown.

[0118] In this step, the plurality of LED elements 20 are brought into contact with the adhesive resin layer 72 of the transfer substrate 70, so that the plurality of LED elements 20 are bonded and held by the transfer substrate 70. Specifically, the surface of the LED element 20 opposite to the surface on which the electrode 21 (the anode electrode 21EA and the cathode electrode 21EK) is formed is bonded and held on one surface 72f of the adhesive resin layer 72. In other words, the LED element 20 is bonded and held on the transfer substrate 70 in such a manner that the surface on which the anode electrode 21EA and the plurality of cathode electrodes 21EK are formed faces the substrate structure SUB1. In addition, the anode electrode 21EA and the cathode electrode 21EK of the LED element 20 are sometimes collectively referred to as the electrode 21.

[0119] Each LED element 20 bonded and held on the transfer substrate 70 is first formed on a sapphire substrate, for example. Each of the plurality of LED elements 20 completed on the sapphire substrate is temporarily transferred to a first transfer substrate, and then transferred from the first transfer substrate to the transfer substrate 70 . Fig.11 The figure shows a state after a plurality of LED elements 20 are transferred from the first transfer substrate to the transfer substrate 70. By transferring a plurality of LED elements 20 formed on the sapphire substrate to the transfer substrate 70 via the first transfer substrate, the LED elements 20 are held on the transfer substrate 70 in an orientation in which the electrode 21 side faces the substrate structure SUB1.

[0120] <Component pressing process>

[0121] Next, in Figure 6 In the component pressing step S4 shown in FIG. Fig.12 As shown, the transfer substrate 70 on which the plurality of LED elements 20 are bonded and held is pressed against the substrate structure SUB1 prepared in the substrate structure preparation step S1 . Fig.12 as well as FIG. 13A to FIG. 13C is a diagram illustrating the component pressing process. More specifically, Fig.12 2 is an enlarged cross-sectional view showing a state in which the transfer substrate is pressed against the substrate structure in the element pressing step. FIG. 13A to FIG. 13C Schematic diagram for explaining the component pressing process when the substrate structure SUB1 is warped. Fig.14 This is a cross-sectional view for explaining a modified example of the transfer substrate.

[0122] In this step, the electrodes 21 of the LED elements 20 bonded and held in the plurality of holding regions 74 of the adhesive resin layer 72 provided on the transfer substrate 70 are respectively opposed to the plurality of bump electrodes 33 formed on the substrate structure SUB1, and in this state, the transfer substrate 70 is pressed toward the substrate structure SUB1. As a result, the electrodes 21 of the plurality of LED elements 20 held on the transfer substrate 70 are respectively in contact with the plurality of bump electrodes 33.

[0123] Here, for example, it is assumed that the circuit substrate 10 constituting the substrate structure SUB1 is warped. In this case, in order to make the electrodes 21 of the plurality of LED elements 20 contact the corresponding bump electrodes 33, it is necessary to press the transfer substrate 70 against the substrate structure SUB1 side more strongly than when the circuit substrate 10 is not warped. With this, there is a concern that the adhesive resin layer 72 may adhere to the substrate structure SUB1 side including the circuit substrate 10. However, by providing a cover film 73 on the surface of the adhesive resin layer 72 constituting the transfer substrate 70, it is possible to suppress the adhesive resin layer 72 from adhering to the substrate structure SUB1.

[0124] Specifically, for example Fig.13A As shown in FIG. 1 , it is assumed that a warp is generated on the substrate structure SUB1 so that the transfer substrate 70 side is convex, and the warp is largest at the center of the substrate structure SUB1 in the X direction. In this case, if the transfer substrate 70 is pressed toward the substrate structure SUB1, as shown in FIG. Fig. 13B As shown, the electrodes 21 of the LED element 20 first contact the bump electrodes 33 at the center of the substrate structure SUB1 in the X direction where the warpage is the largest. In contrast, the electrodes 21 of the LED element 20 do not contact the bump electrodes 33 at both ends of the substrate structure SUB1 in the X direction.

[0125] In order to make the electrodes 21 of all LED elements 20 contact the bump electrodes 33, it is necessary to press the transfer substrate 70 more strongly toward the substrate structure SUB1. Fig. 13C As shown, the electrodes 21 of all LED elements 20 can be brought into contact with the bump electrodes 33 of the substrate structure SUB1. However, for example, in the center portion of the substrate structure SUB1 in the X direction, the adhesive resin layer 72 is crushed by the LED element 20. In other words, the LED element 20 is pressed into the adhesive resin layer 72.

[0126] When the area of ​​the substrate structure SUB1 is relatively small, the warpage is suppressed to be relatively small, so that the LED element 20 is difficult to be pressed into the adhesive resin layer 72. On the other hand, when the area of ​​the substrate structure SUB1 is relatively large, the warpage is also likely to become large, and with this, the LED element 20 is likely to be pressed into the adhesive resin layer 72. And, since the LED element 20 is pressed into the adhesive resin layer 72 in this way, the adhesive resin layer 72 is easy to adhere to the surface of the substrate structure SUB1.

[0127] However, by providing the cover film 73 on the surface of the adhesive resin layer 72, it is possible to suppress the adhesion of the adhesive resin layer 72 to the substrate structure SUB1. More specifically, even when the LED element 20 is pressed into the adhesive resin layer 72, the cover film 73 exists between the adhesive resin layer 72 and the substrate structure SUB1. Therefore, the adhesive resin layer 72 does not directly contact the surface of the substrate structure SUB1. Therefore, it is possible to suppress the adhesion of the adhesive resin layer 72 to the substrate structure SUB1.

[0128] In particular, when the thickness of the adhesive resin layer 72 is thicker than the height of the LED element 20, the LED element 20 is pressed into the adhesive resin layer 72, making it easy for the adhesive resin layer 72 to adhere to the substrate structure SUB 1. Even in this case, since the cover film 73 is provided on the surface of the adhesive resin layer 72, the adhesion of the adhesive resin layer 72 to the substrate structure SUB 1 can be effectively suppressed.

[0129] In addition, if the adhesive resin layer 72 is crushed by the LED element 20, there is a case where the surface of the substrate structure SUB1 abuts against the cover film 73. In this case, the adhesive resin layer 72 is also subjected to pressure from the cover film 73. However, the cover film 73 is continuously formed in the outer area of ​​the holding area 74 of the transfer substrate 70, and its area is relatively wide. More specifically, the contact area between the cover film 73 and the adhesive resin layer 72 is wider than the contact area between each LED element 20 and the adhesive resin layer 72. Therefore, the cover film 73 is difficult to be pressed into the adhesive resin layer 72 compared with the LED element 20.

[0130] The thickness of the cover film 73 is not particularly limited, but is preferably thinner than the height of the LED element 20. In other words, when the LED element 20 is bonded and held by the adhesive resin layer 72, it is preferred that the front end of the LED element 20 is located outside the surface of the cover film 73 in the Z direction. Thus, in the above-mentioned element holding step S3, it is easy to bond and hold the LED element 20 to the adhesive resin layer 72 of the transfer substrate 70.

[0131] On the other hand, from the viewpoint of further suppressing the adhesion of the adhesive resin layer 72 to the substrate structure SUB1, for example, Fig.14As shown, the thickness of the cover film 73 is preferably thicker than the height of the LED element 20. In other words, the thickness of the cover film 73 is preferably equal to or slightly thicker than the sum of the height of the LED element 20 and the height of the bump electrode 33 of the substrate structure SUB1.

[0132] Thus, even when the LED element 20 is pressed into the adhesive resin layer 72, a sufficient gap can be ensured between the adhesive resin layer 72 and the substrate structure SUB1. Thus, it is possible to more reliably suppress the adhesion of the adhesive resin layer 72 to the substrate structure SUB1. Since a sufficient gap is ensured between the adhesive resin layer 72 and the substrate structure SUB1, for example, when the LED element 20 is pressed into the adhesive resin layer 72, it is possible to suppress the adhesion of the adhesive resin layer 72 to the substrate structure SUB1 through the gap between the LED element 20 and the cover film 73.

[0133] In addition, when the thickness of the cover film 73 is made thicker than the height of the LED element 20, it is difficult to bond and hold the LED element 20 to the adhesive resin layer 72 of the transfer substrate 70 in the element holding step S3. However, by considering the shape of the first transfer substrate, for example, it is possible to easily bond and hold the LED element 20 held on the first transfer substrate to the adhesive resin layer 72 of the transfer substrate 70. As an example, a protrusion having a smaller area than the holding region 74 is provided on a portion of the first transfer substrate that is opposite to the holding region 74, and the LED element 20 is held on the protrusion.

[0134] In addition, in the present embodiment, the substrate structure SUB1 is warped to form a curved surface centered on the side opposite to the transfer substrate 70, and the warping is greatest at the center of the substrate structure SUB1 in the X direction, but the state of the warping is not limited to this. For example, the same effect can be obtained when the substrate structure SUB1 is warped to form a curved surface centered on the transfer substrate 70 side. Moreover, the same effect can be obtained when the transfer substrate 70 is warped as described above.

[0135] <Laser irradiation process>

[0136] Next, in Figure 6 In the laser irradiation step S5 shown in FIG. Fig.15 As shown, laser light source LZS irradiates the bump electrodes 33 and the contact portions where electrodes 21 of the LED elements 20 are in contact with the bump electrodes 33 . Thus, the electrodes 21 of the LED elements 20 are bonded to the bump electrodes 33 . Fig.15 is a diagram illustrating the laser irradiation process. More specifically, Fig.15This is an enlarged cross-sectional view schematically showing a state where a contact portion between the electrode 21 of the LED element 20 and the bump electrode 33 is irradiated with laser light.

[0137] In this process, the contact portion between the electrode 21 of each LED element 20 and the bump electrode 33 is irradiated with laser light LZ to heat the contact portion. More specifically, heat is applied to the bump electrode 33 to melt the solder contained in the bump electrode 33, and the bump electrode 33 is bonded to the electrode 21 of each LED element 20 by the solder.

[0138] In addition, there may be a process of pre-forming a solder film on the anode electrode 21EA and the cathode electrode 21EK of the LED element 20 before this process. The bump electrode 33 containing solder and the solder film formed on the anode electrode 21EA and the cathode electrode 21EK can be easily integrated. Therefore, by forming the solder film on the anode electrode 21EA and the cathode electrode 21EK, it is easier to join the bump electrode 33 and each electrode 21 of the LED element 20 in this process.

[0139] <Component peeling process>

[0140] Next, in Figure 6 In the element stripping step S6 shown in FIG. Fig.16 As shown, the plurality of LED elements 20 and the adhesive resin layer 72 of the transfer substrate 70 are peeled off. Fig.16 is a diagram illustrating the element peeling process. More specifically, Fig.16 It is an enlarged cross-sectional view showing a state where the adhesive resin layer 72 of the transfer substrate 70 and the plurality of LED elements 20 are peeled off.

[0141] In this process, the transfer substrate 70 is moved in the Z direction so that the distance between the transfer substrate 70 and the substrate structure SUB1 is increased. At this time, the electrodes 21 of the plurality of LED elements 20 are bonded to the bump electrodes 33 of the substrate structure SUB1. In other words, the plurality of LED elements 20 are mounted on the substrate structure SUB1, and the fixing strength between the electrodes 21 of the LED elements 20 and the bump electrodes 33 is higher than the bonding strength between each LED element 20 and the adhesive resin layer 72. Therefore, by moving the transfer substrate 70 in a direction away from the substrate structure SUB, the interface between the adhesive resin layer 72 and the LED element 20 is peeled off. Through this process, a display device DPS1 having a plurality of LEDs 20 mounted on the substrate structure SUB1 can be obtained.

[0142] As described above, regarding the transfer substrate 70 of the present disclosure, a cover film 73 having a surface adhesive force weaker than that of the adhesive resin layer 72 is provided on the side of the adhesive resin layer 72 opposite to the support substrate 71, so as to cover the area outside the holding area 74 of the adhesive resin layer 72. Thus, the adhesive resin layer 72 can be prevented from being fixed to the substrate structure SUB1.

[0143] As described above, there is a concern that a portion of the adhesive resin layer 72 may adhere to the surface of the substrate structure SUB 1 in the element pressing step S4. In addition, in this state, if the laser LZ is irradiated in the laser irradiation step S5, there is a concern that a portion of the adhesive resin layer 72 (adhesive resin) adhered to the substrate structure SUB 1 may be fixed to the substrate structure SUB 1.

[0144] More specifically, if heat is applied to the bump electrode 33 in the laser irradiation step S5, the temperature of the substrate structure SUB1 also rises. Therefore, if the adhesive resin layer 72 is attached to the surface of the substrate structure SUB1, the attached adhesive resin layer 72 may be cured by the heat. In this state, if the transfer substrate 70 is separated from the substrate structure SUB1 in the element peeling step S6, there is a concern that the cured adhesive resin layer 72 will remain on the surface of the substrate structure SUB1.

[0145] However, the transfer substrate 70 of the present disclosure has a cover film 73 provided on the surface of the adhesive resin layer 72 and having a surface adhesive force weaker than that of the adhesive resin layer 72, thereby suppressing the adhesion of the adhesive resin layer 72 to the substrate structure SUB1 in the element pressing step S4. Therefore, even if the laser light LZ is irradiated in the laser irradiation step S5, the adhesive resin layer 72 can be suppressed from being fixed to the substrate structure SUB1. As a result, diffuse reflection of light in the display device DPS1 can be suppressed, and the performance of the display device DPS1 can be improved.

[0146] Although the embodiments and representative modified examples have been described above, the above-described technology can be applied to various modified examples other than the exemplified modified examples. For example, the above-described modified examples can be combined with each other.

[0147] It is known that within the scope of the concept of the present invention, if it is a variety of changes and modifications that can be thought of by those skilled in the art, then these changes and modifications also belong to the scope of the present invention. For example, embodiments obtained by those skilled in the art appropriately adding, deleting or changing the design of the components of the above-mentioned embodiments, or embodiments obtained by adding, omitting or changing the conditions of the processes, as long as they have the gist of the present invention, are included in the scope of the present invention.

[0148] For example, in the above-mentioned embodiment, in the transfer substrate preparation step S2, the transfer substrate 70 having the cover film 73 provided on the surface of the adhesive resin layer 72 is prepared, but the cover film 73 may not necessarily be prepared in the transfer substrate preparation step S2. That is, the cover film 73 only needs to be provided on the surface of the adhesive resin layer 72 before the component pressing step S4. In other words, in the component pressing step S4, the transfer substrate 70 only needs to have the cover film 73 as described above.

[0149] <Note>

[0150] In addition, the present technology can take the following configurations.

[0151] (Note 1)

[0152] A transfer substrate, comprising:

[0153] support base plate;

[0154] an adhesive resin layer continuously provided on one surface of the support substrate and having a plurality of holding regions for bonding and holding the element; and

[0155] A covering film is provided on a surface of the adhesive resin layer opposite to the support substrate so as to cover an area outside the retaining area of ​​the adhesive resin layer, and the adhesive force of the surface of the covering film is weaker than that of the adhesive resin layer.

[0156] (Note 2)

[0157] In the transfer substrate described in Supplementary Note 1,

[0158] The cover film is provided so as to surround the periphery of the holding region, and has openings at positions facing the respective holding regions.

[0159] (Note 3)

[0160] In the transfer substrate described in Supplementary Note 2,

[0161] The opening portion has an opening shape along a planar shape of the component held by the holding region.

[0162] (Note 4)

[0163] In the transfer substrate described in Supplement 2 or 3,

[0164] A gap between the opening and the holding region in a plan view is 1 μm to 2.5 μm.

[0165] (Note 5)

[0166] In the transfer substrate according to any one of Supplementary Notes 1 to 4,

[0167] The thickness of the cover film is thinner than the height of the element.

[0168] (Note 6)

[0169] In the transfer substrate according to any one of Supplementary Notes 1 to 4,

[0170] The thickness of the cover film is thicker than the height of the element.

[0171] (Note 7)

[0172] In any one of Supplementary Notes 1 to 6, the transfer substrate

[0173] The thickness of the adhesive resin layer is thicker than the height of the element.

[0174] (Note 8)

[0175] In any one of Supplementary Notes 1 to 7,

[0176] The cover film is a metal thin film made of a metal material.

[0177] (Note 9)

[0178] A method for manufacturing an electronic device comprises the following steps:

[0179] (a) preparing a transfer substrate according to any one of Supplementary Notes 1 to 8,

[0180] (b) a step of bonding and holding the element in the plurality of holding regions of the adhesive resin layer constituting the transfer substrate,

[0181] (c) preparing a circuit substrate on which a plurality of bump electrodes are arranged, and pressing the transfer substrate on which the element is bonded and held in the plurality of holding regions against the circuit substrate so that the plurality of bump electrodes are in contact with the electrodes of the element bonded and held in the plurality of holding regions, respectively;

[0182] (d) a step of bonding the bump electrodes to the electrodes of the element bonded and held in the plurality of holding regions by heating in a state where the plurality of bump electrodes are in contact with each other.

[0183] (Note 10)

[0184] A method for manufacturing an electronic device, comprising:

[0185] (a) preparing a transfer substrate including a support substrate and an adhesive resin layer continuously provided on one surface of the support substrate and having a plurality of holding regions for bonding and holding a component,

[0186] (b) a step of bonding and holding the element in the holding region of the adhesive resin layer constituting the transfer substrate,

[0187] (c) preparing a circuit substrate on which a plurality of bump electrodes are arranged, and pressing the transfer substrate on which the element is bonded and held against the circuit substrate so that the plurality of bump electrodes are in contact with the electrodes of the element held by the plurality of holding regions, respectively;

[0188] (d) a step of bonding the bump electrodes to the electrodes of the element by heating in a state where the plurality of bump electrodes are in contact with the electrodes of the element bonded and held in the plurality of holding regions, respectively;

[0189] In the step (c), the transfer substrate is pressed against the circuit substrate in a state where the region outside the holding region of the adhesive resin layer is covered with a cover film having a surface adhesive force weaker than that of the adhesive resin layer.

[0190] (Note 11)

[0191] In the method for manufacturing an electronic device described in Supplement 10,

[0192] The cover film is provided to surround the periphery of the holding region, and has openings at positions facing the respective holding regions.

[0193] (Note 12)

[0194] In the method for manufacturing an electronic device described in Supplement 11,

[0195] The opening portion has an opening shape along a planar shape of the component held by the holding region.

[0196] (Note 13)

[0197] In the method for manufacturing an electronic device according to Supplement 11 or 12,

[0198] A gap between the opening and the holding region in a plan view is 1 μm to 2.5 μm.

[0199] (Note 14)

[0200] In the method for manufacturing an electronic device according to any one of Supplementary Notes 10 to 13,

[0201] The thickness of the cover film is thinner than the height of the element.

[0202] (Note 15)

[0203] In the method for manufacturing an electronic device according to any one of Supplementary Notes 10 to 13,

[0204] The thickness of the cover film is thicker than the height of the element.

[0205] (Note 16)

[0206] In the method for manufacturing an electronic device described in Supplement 15,

[0207] The thickness of the cover film is thicker than the sum of the height of the element and the height of the bump electrode.

[0208] (Note 17)

[0209] In the method for manufacturing an electronic device according to any one of Supplementary Notes 10 to 16,

[0210] The thickness of the adhesive resin layer is thicker than the height of the element.

[0211] (Note 18)

[0212] In the method for manufacturing an electronic device according to any one of Supplementary Notes 10 to 17,

[0213] The cover film is a metal thin film made of a metal material.

[0214] Industrial Applicability

[0215] The utility model can be used for a transfer substrate used when transferring an electronic component (element) and a method for manufacturing an electronic device on which the electronic component is mounted using the transfer substrate.

Claims

1. A transfer substrate, characterized in that: have: support base plate; An adhesive resin layer is continuously provided on one surface of the support substrate and has a plurality of holding areas for bonding and holding the element; as well as A covering film is provided on a surface of the adhesive resin layer opposite to the support substrate so as to cover an area outside the retaining area of ​​the adhesive resin layer, and the adhesive force of the surface of the covering film is weaker than that of the adhesive resin layer.

2. The transfer substrate according to claim 1, wherein The cover film is provided so as to surround the periphery of the holding region, and has openings at positions facing the respective holding regions.

3. The transfer substrate according to claim 2, characterized in that The opening portion has an opening shape along a planar shape of the element held by the holding region.

4. The transfer substrate according to claim 1, wherein The thickness of the cover film is thinner than the height of the element.

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