Method for manufacturing connecting film and connecting structure

Abstract

To provide a connection film which can obtain excellent landing property of a chip component by irradiation with a laser beam, and a method for manufacturing a connection structure.SOLUTION: A connection film contains a rubber component, and has durometer A hardness of 20-40, and a tensile elastic modulus at a temperature of 30°C and a frequency of 200 Hz in a dynamic viscoelasticity test using an indentation tester of 0.2-60 MPa. The connection film further contains a film formative resin, a thermosetting resin, a curing agent and an inorganic filler, and has a storage elastic modulus at a temperature of 30°C measured in a tensile mode according to JIS K 7244 after curing of 0.1 GPa or more. Thereby, excellent landing property of a chip component by irradiation with a laser beam can be obtained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This technology relates to a connecting film for connecting chip components to a substrate, and a method for manufacturing a connecting structure. [Background technology]

[0002] In recent years, the development of micro-LEDs has been active as the next-generation display technology following LCDs (Liquid Crystal Displays) and OLEDs (Organic Light Emitting Diodes). A challenge with micro-LEDs is the need for a technology called mass transfer, which involves mounting micro-sized LEDs onto a panel substrate, and this technology is being researched in various fields.

[0003] A currently dominant method of mass transfer involves using a stamping material to transfer LEDs to the panel substrate. Figure 15 schematically shows the stamping method of mass transfer. In the stamping method, as shown in Figures 15A and 15B, the LED 101 is transferred from the transfer material 102 to the stamping material 103 and picked up, and then, as shown in Figures 15C and 15D, the LED 101 is attached to the connecting film 105 of the panel substrate 104. However, the method using stamping material has drawbacks: the pitch of the LED 101 depends on the pattern of the stamping material 103, resulting in low design flexibility, a low chip transfer rate, and a very long processing time, making it unsuitable for mass production.

[0004] Therefore, a chip placement method using lasers is currently attracting attention (see, for example, Patent Documents 1 to 4). Figure 16 is a schematic diagram showing a laser-based mass transfer. In the laser method, as shown in Figures 16A and 16B, the LED 111 is transferred from the transfer material 112 to the release material 113 and picked up, and as shown in Figure 15C, laser light is shone onto the release material 113 to cause the LED 111 to land on the connecting film 115 of the panel substrate 114. Compared to stamp materials, laser-based chip transfer offers greater design flexibility and a very fast chip transfer cycle time.

[0005] However, in the chip placement method using lasers, the LEDs are ejected and land on the panel substrate at a very high speed, which can cause defects such as the LEDs shifting, deforming, falling out, or breaking, as shown in Figure 16D. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-096144 [Patent Document 2] Japanese Patent Publication No. 2020-145243 [Patent Document 3] Japanese Patent Publication No. 2019-176154 [Patent Document 4] Japanese Patent Publication No. 2020-053558 [Overview of the project] [Problems that the invention aims to solve]

[0007] This technology was proposed in light of the conventional situation described above, and provides a connecting film and a method for manufacturing a connecting structure that can obtain excellent adhesion elasticity of chip components by irradiation with laser light. [Means for solving the problem]

[0008] The connecting film related to this technology contains rubber components, has a durometer A hardness of 20 to 40, and has a storage modulus of 60 MPa or less in a dynamic viscoelasticity test using an indentation test device at a temperature of 30°C and a frequency of 200 Hz.

[0009] The connecting film substrate according to this technology comprises the aforementioned connecting film and a substrate that is transparent to laser light.

[0010] The manufacturing method for the connection structure according to this technology comprises a projecting step in which a chip component provided on a substrate that is transparent to laser light is placed opposite a connection film on a wiring board, and laser light is irradiated from the substrate side to cause the chip component to land on the connection film, and a connecting step in which the chip component and the wiring board are connected, wherein the connection film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz.

[0011] The manufacturing method of the connection structure according to this technology comprises a projecting step in which a connection film on the electrode surface of a chip component provided on a substrate that is transparent to laser light is placed opposite a wiring board, and laser light is irradiated from the substrate side to project the chip component onto the wiring board via the connection film, and a connecting step in which the chip component and the wiring board are connected, wherein the connection film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. [Effects of the Invention]

[0012] This technology provides excellent shock absorption, resulting in superior impact elasticity for chip components. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic cross-sectional view showing a state in which a light-emitting element provided on a substrate and an anisotropic conductive film on a wiring board are facing each other. [Figure 2] Figure 2 is an enlarged view showing the opposing light-emitting elements and the connecting film on the wiring board. [Figure 3] Figure 3 is a schematic cross-sectional view showing the state in which light-emitting elements are transferred to predetermined positions on a wiring board and arranged by irradiating them with laser light from the substrate side. [Figure 4] Figure 4 is a schematic cross-sectional view showing a circuit board with light-emitting elements mounted on it. [Figure 5]FIG. 5 is a cross-sectional view schematically showing a state in which an anisotropic conductive film provided on a substrate and a wiring board are opposed to each other. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a state in which laser light is irradiated from the substrate side, and individual pieces of the anisotropic conductive film are transferred to predetermined positions on the wiring board and arranged. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a state in which a light-emitting element provided on a substrate and an anisotropic conductive film on the wiring board are opposed to each other. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a state in which laser light is irradiated from the substrate side, and the light-emitting element is transferred to a predetermined position on the wiring board and arranged. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a state in which a light-emitting element is mounted on individual pieces arranged at predetermined positions on the wiring board. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a state in which laser light is irradiated from the substrate side, and individual pieces of the anisotropic conductive film are transferred and arranged on the wiring board in electrode units. [Figure 11] FIG. 11 is a cross-sectional view schematically showing a state in which a light-emitting element provided on a substrate and individual pieces transferred and arranged in electrode units on the wiring board are opposed to each other. <s [Figure 12] FIG. 12 is a cross-sectional view schematically showing a state in which laser light is irradiated from the substrate side, and the light-emitting element lands on and is arranged on individual pieces on corresponding electrodes. [Figure 13] FIG. 13 is a cross-sectional view schematically showing a state in which a light-emitting element is mounted on individual pieces on the wiring board. [Figure 14] FIG. 14 is a cross-sectional view schematically showing a state in which a connection film provided on an electrode surface of a light-emitting element and a wiring board are opposed to each other. [Figure 15] FIG. 15 is a diagram schematically showing a stamp method of mass transfer. [Figure 16] FIG. 16 is a diagram schematically showing a laser method of mass transfer.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The embodiments of this technology will be described in detail below with reference to the drawings, in the following order. 1. Connecting film 2. Manufacturing method of the connecting structure 3. First Embodiment 4. Second Example

[0015] <1. Connecting film> The connecting film according to this embodiment contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of 60 MPa or less in a dynamic viscoelasticity test using an indentation test device at a temperature of 30°C and a frequency of 200 Hz. As a result, excellent shock absorption is obtained, which suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of chip components, and improves the transfer rate of chip components by laser irradiation.

[0016] The rubber component is not particularly limited as long as it is an elastomer with high cushioning (shock absorption) properties. Specific examples include acrylic rubber, silicone rubber, butadiene rubber, and polyurethane resin (polyurethane elastomer). Among these, it is preferable that the rubber component be one or more selected from acrylic rubber and silicone rubber. The rubber component content may be 1 to 100 wt%, and when thermosetting resins, thermoplastic resins, etc., are included, the rubber component content is preferably 1 to 20 wt%, more preferably 2 to 10 wt%.

[0017] The durometer A hardness of the connecting film is 20 to 40, preferably 20 to 35, and more preferably 20 to 30. If the durometer A hardness is too high, the connecting film is too hard, which tends to cause defects such as deformation and breakage of the chip components. If the durometer A hardness is too low, the connecting film is too soft, which tends to cause defects such as misalignment of the chip components. The durometer A hardness of the connecting film can be measured using durometer A in accordance with JIS K 6253, and can be measured using rubber hardness (Japanese Industrial Standard JIS-A hardness).

[0018] The storage modulus of elasticity in a dynamic viscoelasticity test using a bonding film indentation test apparatus at a temperature of 30°C and a frequency of 200Hz is 60MPa or less, preferably 30MPa or less, and more preferably 10MPa or less. If the storage modulus of elasticity at 30°C and 200Hz is too high, the impact of the chip component ejected at high speed by laser irradiation cannot be absorbed, and the transfer rate of the chip component tends to decrease. The storage modulus of elasticity at 30°C and 200Hz can be measured using an indentation test apparatus, for example, by using a flat punch with a diameter of 100μm, setting the target indentation depth to 1μm, and sweeping in the frequency range of 1 to 200Hz.

[0019] Furthermore, the connecting film further contains a film-forming resin, a thermosetting resin, a curing agent, and an inorganic filler, and preferably has a storage modulus of elasticity at 30°C measured in tensile mode according to JIS K7244 after curing of 100 MPa or more, and more preferably 2000 MPa or more. If the storage modulus of elasticity at 30°C is too low, good conductivity cannot be obtained, and connection reliability tends to decrease. The storage modulus of elasticity at 30°C can be measured in tensile mode using a viscoelasticity tester (Vibron) in accordance with JIS K7244, for example, under measurement conditions of a frequency of 11 Hz and a heating rate of 3°C / min.

[0020] The thermosetting binder containing a film-forming resin, a thermosetting resin, and a curing agent is not particularly limited and includes, for example, a thermo-anionic polymerization resin composition containing an epoxy compound and a thermo-anionic polymerization initiator, a thermo-cationic polymerization resin composition containing an epoxy compound and a thermo-cationic polymerization initiator, and a thermo-radical polymerization resin composition containing a (meth)acrylate compound and a thermo-radical polymerization initiator. Note that (meth)acrylate compound includes both acrylic monomers (oligomers) and methacrylic monomers (oligomers).

[0021] Among these thermosetting binders, it is preferable that the thermosetting resin contains an epoxy compound and the curing agent is a thermal cationic polymerization initiator. This suppresses the curing reaction by laser light and allows for rapid curing by heat. In the following, as a specific example, a thermal cationic polymerization resin composition containing a film-forming resin, an epoxy compound, and a thermal cationic polymerization initiator will be given and explained.

[0022] The film-forming resin is, for example, a high molecular weight resin with an average molecular weight of 10,000 or more, and from the viewpoint of film-forming properties, an average molecular weight of about 10,000 to 80,000 is preferred. Examples of film-forming resins include phenoxy resins, polyester resins, polyurethane resins, polyester urethane resins, acrylic resins, polyimide resins, and butyral resins, which may be used individually or in combination of two or more types. Among these, phenoxy resin is preferred from the viewpoint of film formation state and connection reliability. The content of the film-forming resin is preferably 20 to 50 parts by mass, more preferably 25 to 45 parts by mass or less, and even more preferably 35 to 45 parts by mass, per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component.

[0023] The epoxy compound is not particularly limited as long as it is an epoxy compound having one or more epoxy groups in its molecule. For example, it may be a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a urethane-modified epoxy resin. Among these, a high-purity bisphenol A type epoxy resin is preferably used. A specific example of a high-purity bisphenol A type epoxy resin is the product name "YL980" manufactured by Mitsubishi Chemical Corporation. The epoxy compound content is preferably 30 to 60 parts by mass, more preferably 35 to 55 parts by mass or less, and even more preferably 35 to 45 parts by mass, per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component.

[0024] As the thermal cationic polymerization initiator, known thermal cationic polymerization initiators for epoxy compounds can be used. For example, those that generate an acid capable of cationic polymerization of cationic polymer-type compounds upon heating, such as known iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc., can be used. Among these, aromatic sulfonium salts that exhibit good latent properties with respect to temperature are preferably used. A specific example of an aromatic sulfonium salt-based polymerization initiator is, for example, the product name "SI-60L" manufactured by Sanshin Chemical Industry Co., Ltd. The content of the thermal cationic polymerization initiator is preferably 1 to 15 parts by mass, more preferably 1 to 10 parts by mass or less, and even more preferably 3 to 8 parts by mass, per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component.

[0025] Inorganic fillers can be used to adjust the durometer A hardness, storage modulus at 200 Hz, and storage modulus after curing of thermosetting binders. Examples of inorganic fillers include silica, talc, titanium oxide, calcium carbonate, and magnesium oxide. Inorganic fillers may be used alone or in combination of two or more types.

[0026] The inorganic filler content is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass or less, and even more preferably 8 to 12 parts by mass, per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component. When two or more types of inorganic fillers are used in combination, it is preferable that the total amount of inorganic fillers in the thermosetting binder is within the above range. In particular, by having a rubber component content of 2 to 10 parts by mass per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component, and an inorganic filler content of 8 to 12 parts by mass per 100 parts by mass of the total of the film-forming resin, thermosetting resin, curing agent, inorganic filler, and rubber component, it is possible to obtain the desired durometer A hardness, storage modulus at a frequency of 200 Hz, and storage modulus after curing.

[0027] In addition, other additives that may be incorporated into the thermosetting binder, as needed, include silane coupling agents, diluent monomers, fillers, softeners, colorants, flame retardants, thixotropic agents, etc.

[0028] Furthermore, the connecting film may further contain conductive particles and be an anisotropic conductive film. The conductive particles can be appropriately selected from those used in known anisotropic conductive films. Examples include metal particles such as nickel, copper, silver, gold, palladium, and solder; and metal-coated resin particles, where the surface of resin particles such as polyamide and polybenzoguanamine is coated with a metal such as nickel or gold. This enables conductivity even when the chip component does not have connection points such as solder bumps.

[0029] Furthermore, it is preferable that the conductive particles are arranged in a plane direction. This arrangement ensures a uniform particle density, further improving the transfer rate of chip components by laser irradiation.

[0030] The particle size of the conductive particles is not particularly limited, but the lower limit of the particle size is preferably 2 μm or more, and the upper limit of the particle size is preferably 50 μm or less, and more preferably 20 μm or less, from the viewpoint of the capture efficiency of conductive particles in the connecting structure. The particle size of the conductive particles can be measured using an image-type particle size analyzer (for example, FPIA-3000: manufactured by Malvern). The number of particles is preferably 1000 or more, preferably 2000 or more. The particle surface density of the conductive particles can be determined according to the electrode area of ​​the chip component, for example, 500 to 100000 pcs / mm 2 It can be set to the range of

[0031] The lower limit of the thickness of the connecting film may be the same as the particle diameter of the conductive particles, and preferably 1.3 times or more the conductive particle diameter or 3 μm or more. The upper limit of the thickness of the connecting film may be 20 μm or less or 2 times or less the particle diameter of the conductive particles. The connecting film may also have an adhesive layer or tack layer that does not contain conductive particles laminated into it, and the number of layers and the lamination surface can be appropriately selected according to the target and purpose. The insulating resin of the adhesive layer or tack layer can be the same as that of the connecting film. The film thickness can be measured using a known micrometer or digital thickness gauge. The film thickness can be determined by measuring at 10 or more locations and averaging the results. <2. Manufacturing method of connecting structure>

[0032] [First Embodiment] The manufacturing method for the connection structure according to the first embodiment comprises a striking step in which a chip component provided on a substrate transparent to laser light and a connection film on a wiring board are placed facing each other, and laser light is irradiated from the substrate side to cause the chip component to land on the connection film, and a connecting step in which the chip component and the wiring board are connected, wherein the connection film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. As a result, defects such as displacement, deformation, breakage, and detachment of the chip component are suppressed in the striking step, and the chip component can be transferred and arranged with high precision and efficiency, thereby shortening the cycle time.

[0033] Examples of chip components include semiconductor chips and LED chips, and are not particularly limited. However, the manufacturing method of the connection structure related to this technology can be suitably used in mass transfers for mounting a large number of micro-sized LED chips onto a panel substrate, which is a wiring board.

[0034] The following describes a method for manufacturing a connected structure, specifically a method for manufacturing a display device in which multiple light-emitting elements, which are LED chips, are arranged on a wiring board, which is a panel substrate, to form a light-emitting element array.

[0035] As the light-emitting element, a so-called flip-chip type LED having a first conductivity type electrode and a second conductivity type electrode on one side can be used. The light-emitting elements are arranged on the substrate corresponding to each subpixel that makes up one pixel, forming a light-emitting element array. One pixel may be composed of, for example, three subpixels R (red), G (green), and B (blue), four subpixels RGBW (white) and RGBY (yellow), or two subpixels RG and GB.

[0036] Methods for arranging subpixels include, for example, stripe arrangement, mosaic arrangement, and delta arrangement for RGB. Stripe arrangement arranges RGB pixels in vertical stripes, enabling high-resolution images. Mosaic arrangement arranges identical RGB colors diagonally, producing a more natural image than stripe arrangement. Delta arrangement arranges RGB pixels in a triangle, with each dot shifted by half a pitch between fields, resulting in a more natural image display.

[0037] Table 1 shows the estimated lateral pitch between RGB chips, estimated chip size, and estimated electrode size relative to the PPI (Pixels Per Inch) when each RGB chip is arranged horizontally. The minimum chip distance is assumed to be 5 μm, and the estimated RGB distance is maximized when the chips are evenly spaced. These values ​​were calculated as reference values ​​to consider this technology with a clear application in mind.

[0038] [Table 1]

[0039] As shown in Table 1, a chip size of 10 × 20 μm allows for a resolution of up to 500 PPI. Furthermore, a chip size of 7 × 14 μm allows for a resolution of up to 1000 PPI, and by further reducing the chip size, resolutions exceeding 1000 PPI can be achieved. Note that the chip does not necessarily have to be rectangular; it can also be square.

[0040] The following describes the impaction process (A1), in which a laser beam is irradiated to deposit the light-emitting element onto an anisotropic conductive film, and the connection process (B1), in which the light-emitting element is connected to the wiring board, with reference to Figures 1 to 4.

[0041] [Impact Process (A1)] Figure 1 is a schematic cross-sectional view showing a state in which a light-emitting element provided on a substrate and an anisotropic conductive film on a wiring board are facing each other, and Figure 2 is an enlarged view showing the facing light-emitting element and the connecting film on the wiring board. As shown in Figures 1 and 2, first, in the impact step (A1), the chip component substrate 10 and the anisotropic conductive film 40 on the wiring board 30 are facing each other.

[0042] The chip component substrate 10 comprises a base material 11, a release material 12, and a light-emitting element 20, with the light-emitting element 30 attached to the surface of the release material 12. The substrate 11 can be any material that is transparent to laser light, and is preferably quartz glass which has high light transmittance across all wavelengths.

[0043] The release material 12 only needs to have absorption properties with respect to the wavelength of the laser light, and generates a shock wave upon irradiation with the laser light, which propels the light-emitting element 20 toward the wiring board 30. Examples of the release material 12 include polyimide. The thickness T12 of the release material 12 is, for example, 1 μm or more.

[0044] The light-emitting element 20 comprises a main body 21, a first conductivity type electrode 22, and a second conductivity type electrode 23, and has a horizontal structure in which the first conductivity type electrode 22 and the second conductivity type electrode 23 are arranged on the same plane. The main body 21 comprises a first conductivity type cladding layer made of, for example, n-GaN, and, for example, In x Al y Ga 1-x-y The device comprises an active layer made of an N layer and a second conductivity type cladding layer made of, for example, p-GaN, and has a so-called double heterostructure. The first conductivity type electrode 22 is formed in a part of the first conductivity type cladding layer by a passivation layer, and the second conductivity type electrode 23 is formed in a part of the second conductivity type cladding layer. When a voltage is applied between the first conductivity type electrode 22 and the second conductivity type electrode 23, carriers concentrate in the active layer and light emission occurs through recombination.

[0045] The width W20 of the light-emitting element 20 is, for example, 1 to 100 μm, and the thickness T20 of the light-emitting element 20 is, for example, 1 to 20 μm.

[0046] The wiring board 30 comprises a circuit pattern for a first conductivity type and a circuit pattern for a second conductivity type on a substrate 31, and has a first electrode 32 and a second electrode 33 at positions corresponding to the first conductivity type electrode on the p side and the second conductivity type electrode on the n side, respectively, so that the light-emitting elements are arranged in units of subpixels that constitute one pixel. The wiring board 30 also forms circuit patterns such as data lines and address lines for matrix wiring, and allows the light-emitting elements corresponding to each subpixel that constitutes one pixel to be turned on and off. The wiring board 30 is preferably a light-transmitting substrate, the substrate 31 is preferably glass, PET (Polyethylene Terephthalate), etc., and the circuit patterns, the first electrode 32 and the second electrode 33 are preferably transparent conductive films such as ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), ZnO (Zinc-Oxide), IGZO (Indium-Gallium-Zinc-Oxide).

[0047] The anisotropic conductive film 40 contains conductive particles in a binder, and the thickness T40 of the anisotropic conductive film 40 is, for example, 20 μm or less. The distance D between the light-emitting element 20 and the anisotropic conductive film 40 is preferably 10 to 1000 μm, more preferably 50 to 500 μm, and even more preferably 80 to 200 μm.

[0048] Figure 3 is a schematic cross-sectional view showing the state in which a laser beam is irradiated from the substrate side to transfer and arrange the light-emitting elements to predetermined positions on the wiring board. As shown in Figures 2 and 3, in the impaction process (A1), a laser beam 50 is irradiated from the substrate 11 side to transfer and arrange the light-emitting elements 20 to predetermined positions on the wiring board 21.

[0049] For example, a LIFT (Laser Induced Forward Transfer) device can be used to transfer the light-emitting element 20. The LIFT device includes, for example, a telescope that makes pulsed laser light emitted from a laser device into parallel light, a shaping optical system that uniformly shapes the spatial intensity distribution of the pulsed laser light that has passed through the telescope, a mask that allows the pulsed laser light shaped by the shaping optical system to pass through in a predetermined pattern, a field lens positioned between the shaping optical system and the mask, and a projection lens that reduces and projects the laser light that has passed through the pattern on the mask onto the donor substrate. The chip component substrate 10, which is the donor substrate, is held on the donor stage, and the wiring substrate 30, which is the receptor substrate, is held on the receptor stage.

[0050] As a laser device, for example, an excimer laser that emits laser light with a wavelength of 180 nm to 360 nm can be used. The oscillation wavelengths of the excimer laser are, for example, 193, 248, 308, and 351 nm, and can be suitably selected from these oscillation wavelengths according to the light absorption properties of the release 12 material.

[0051] The mask uses a pattern in which an array of windows of a predetermined size is formed at a predetermined pitch such that the projection at the interface between the base material 11 and the release material 12 becomes an array of desired laser light. In the mask, for example, a pattern is formed on the base material 11 by chromium plating. The window portions where chromium plating is not applied transmit laser light, and the portions where chromium plating is applied block laser light.

[0052] The emitted light from the laser device enters the telescopic optical system and propagates to the shaping optical system ahead. The laser light immediately before entering the shaping optical system is adjusted by the telescopic optical system so as to be substantially parallel light at any position within the moving range of the X-axis of this donor stage. Therefore, it always enters the shaping optical system at substantially the same size and the same angle (perpendicular).

[0053] The laser light that has passed through the shaping optical system enters the mask through the field lens that constitutes the image-side telecentric reduction projection optical system in combination with the projection lens. The laser light that has passed through the mask pattern changes its propagation direction vertically downward by the catadioptric mirror and enters the projection lens. The laser light emitted from the projection lens enters from the side of the base material 11 and is accurately projected at the reduced size of the mask pattern onto a predetermined position of the release material 12 formed on its surface (lower surface).

[0054] The pulse energy of the laser light imaged and irradiated onto the interface between the anisotropic conductive adhesive layer and the base material is preferably 0.001 to 2 J, more preferably 0.01 to 1.5 J, and even more preferably 0.1 to 1 J. The fluence is preferably 0.001 to 2 J / cm 2 and more preferably 0.01 to 1 J / cm 2 and even more preferably 0.05 to 0.5 J / cm 2 The pulse width (irradiation time) is preferably 0.01 to 1×10 9 picoseconds, more preferably 0.1 to 1×10 7 picoseconds, and even more preferably 1 to 1×10 5The pulse duration is picosecond. The pulse frequency is preferably 0.1 to 10,000 Hz, more preferably 1 to 1,000 Hz, and even more preferably 1 to 100 Hz. The number of irradiation pulses is preferably 1 to 30,000,000.

[0055] By using such a lifting device, a shock wave is generated in the release material 12 irradiated with laser light at the interface between the substrate 11 and the release material 12, peeling off multiple light-emitting elements 20 from the substrate 11 and lifting them toward the wiring board 30, allowing the multiple light-emitting elements 20 to land at predetermined positions on the wiring board 30 via the anisotropic conductive film 40. This suppresses defects such as displacement, deformation, breakage, and detachment of the light-emitting elements 20, and enables high-precision and high-efficiency transfer and arrangement of the light-emitting elements 20, thereby shortening the cycle time.

[0056] [Connection process (B1)] Figure 4 is a schematic cross-sectional view showing the state in which light-emitting elements are mounted on a wiring board. As shown in Figure 3, in the connection step (B1), light-emitting elements 20 arranged at predetermined positions on the wiring board 30 are mounted.

[0057] As a method for thermocompressing the light-emitting element 20 to the wiring board 30, a connection method used in known anisotropic conductive films can be appropriately selected and used. For example, the thermocompression conditions are a temperature of 120°C to 260°C, a pressure of 5 MPa to 60 MPa, and a time of 5 seconds to 300 seconds. An anisotropic conductive film is formed when the anisotropic conductive film hardens.

[0058] According to the manufacturing method of the connecting structure of the first embodiment, the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. This suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of chip components in the impact process (A1), and enables the transfer and arrangement of chip components with high precision and efficiency, thereby shortening the cycle time.

[0059] [Second Embodiment] In the first embodiment, the connecting film was attached to the wiring board, but it is also possible to irradiate the individual pieces of the connecting film with a laser beam to transfer them to predetermined positions on the wiring board, and then in the impact step (A1), the chip components may be impacted onto the individual pieces of the connecting film.

[0060] In other words, the method for manufacturing the connection structure according to the second embodiment comprises a transfer step of transferring individual pieces of the connection film onto the wiring board by irradiating a connection film provided on a substrate that is transparent to laser light with a wiring board, and irradiating laser light from the substrate side; a landing step of placing a chip component provided on a substrate that is transparent to laser light with a connection film on the wiring board, and irradiating laser light from the substrate side to land the chip component on an individual piece of the connection film; and a connection step of connecting the chip component and the wiring board, wherein the connection film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz.

[0061] This allows for the transfer and arrangement of individual pieces of the connecting film with high precision and efficiency by irradiating them with laser light. Furthermore, similar to the first embodiment, it is possible to suppress defects such as misalignment, deformation, breakage, and detachment of chip components in the impact process, and to transfer and arrange chip components with high precision and efficiency, thereby shortening the cycle time.

[0062] The following describes the transfer process (X) in which individual pieces of anisotropic conductive film are transferred to predetermined positions on the wiring substrate and arranged, the impact process (A2) in which light-emitting elements are projected onto the individual pieces of anisotropic conductive film by irradiating them with laser light, and the connection process (B2) in which light-emitting elements are connected to the wiring substrate. Components identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0063] [Transfer process (X)] Figure 5 is a schematic cross-sectional view showing an anisotropic conductive film provided on a substrate and a wiring board facing each other. As shown in Figure 5, first, in the transfer process (X), the anisotropic conductive film substrate 60 and the wiring board 30 are placed facing each other.

[0064] The anisotropic conductive film substrate 60 comprises a base material 61 and an anisotropic conductive film 70, with the anisotropic conductive film 70 provided on the surface of the base material 61. The base material 61 can be any material that is transparent to laser light, and is preferably quartz glass having high light transmittance across all wavelengths. A release material may be further provided between the base material 61 and the anisotropic conductive film 70.

[0065] From the viewpoint of laser transferability, the anisotropic conductive film 70 is preferably constructed with conductive particles aligned in the planar direction. Furthermore, the anisotropic conductive film 70 preferably has a maximum absorption wavelength in the range of 180 nm to 360 nm, and an epoxy adhesive containing high-purity bisphenol A type epoxy resin can be preferably used.

[0066] Figure 6 is a schematic cross-sectional view showing the state in which individual pieces of anisotropic conductive film are transferred to predetermined positions on the wiring board and arranged by irradiating them with laser light from the substrate side. As shown in Figure 6, in the transfer process (X), laser light is irradiated from the substrate 61 side to transfer individual pieces 70a of the anisotropic conductive film 70 to predetermined positions on the wiring board 30 and arrange them.

[0067] In the transfer step (X), it is preferable to arrange the individual pieces 70a of the anisotropic conductive film 70 in units of one pixel, and more preferably in units of subpixels constituting one pixel. This makes it possible to accommodate light-emitting element arrays ranging from high PPI (Pixels Per Inch) to low PPI.

[0068] Furthermore, the distance between individual pieces arranged at predetermined positions on the wiring board 30 is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the distance between individual pieces is preferably 3000 μm or less, more preferably 1000 μm or less, and even more preferably 500 μm or less. If the distance between individual pieces is too small, it is preferable to attach the anisotropic conductive film to the entire surface of the wiring board 20, and if the distance between individual pieces is too large, it is preferable to attach the anisotropic conductive film to predetermined positions on the wiring board 30.

[0069] For transferring individual pieces 70a of the anisotropic conductive film 70, a lift apparatus similar to that described above can be used, with the anisotropic conductive film substrate 60, which is the donor substrate, held on the donor stage, and the wiring substrate 30, which is the receptor substrate, held on the receptor stage. The distance between the anisotropic conductive film 70 and the wiring substrate 30 is, for example, 10 to 100 μm. The oscillation wavelength of the laser apparatus is, for example, 193, 248, 308, or 351 nm, and can be suitably selected from these oscillation wavelengths depending on the light absorption properties of the anisotropic conductive film 70 or the release material.

[0070] By using a lifting device, a shock wave is generated in the anisotropic conductive film 70 at the interface between the substrate 61 and the anisotropic conductive film 70, which is irradiated with laser light. This peels off multiple individual pieces 70a from the substrate 61 and lifts them toward the wiring board 30, causing the multiple individual pieces 70a to land in predetermined positions on the wiring board 30. This allows for the transfer and arrangement of individual pieces 70a of the anisotropic conductive film 70 onto the wiring board 30 with high precision and efficiency, thereby shortening the cycle time.

[0071] The reaction rate of the individual pieces 70a of the anisotropic conductive film 70 after the transfer step (X) is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less. A reaction rate of 25% or less of the individual pieces 70a makes it possible to thermocompression-bond the light-emitting element in the connection step (B2). The reaction rate can be determined, for example, using FT-IR.

[0072] [Impact process (A2)] Figure 7 is a schematic cross-sectional view showing a state in which a light-emitting element provided on a substrate and an anisotropic conductive film on a wiring board are facing each other, and Figure 8 is a schematic cross-sectional view showing a state in which laser light is irradiated from the substrate side to transfer the light-emitting element to a predetermined position on the wiring board and arrange them.

[0073] As shown in Figure 7, first, in the impaction step (A2), the chip component substrate 10 and the individual pieces 70a of the anisotropic conductive film on the wiring substrate 30 are placed facing each other. Then, as shown in Figure 8, laser light is irradiated from the substrate 11 side to transfer and arrange the light-emitting elements 20 onto the individual pieces 70a of the anisotropic conductive film on the wiring substrate 30. For the transfer of the light-emitting elements 20, a lift device, for example, can be used, as in the first embodiment.

[0074] [Connection process (B2)] Figure 9 is a schematic cross-sectional view showing a state in which light-emitting elements are mounted on individual pieces arranged at predetermined positions on a wiring board. As shown in Figure 9, in the connection step (B2), the light-emitting elements 20 are mounted on individual pieces 70a arranged at predetermined positions on the wiring board 30. The method for thermocompressing the light-emitting elements 20 to the wiring board 30 is the same as in the first embodiment.

[0075] According to the manufacturing method of the connecting structure of the second embodiment, the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. This suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of chip components in the impact process (A2), and enables the transfer and arrangement of chip components with high precision and efficiency, thereby shortening the cycle time.

[0076] Furthermore, since there is no anisotropic conductive film between the light-emitting elements 20 and the wiring substrate 30 is exposed, the light-emitting elements 20 can be anisotropically connected on the wiring substrate 30. By using a light-transmitting substrate for the wiring substrate 30, superior light transmittance can be obtained compared to the case where an anisotropic conductive film is attached to the entire surface of the wiring substrate 30.

[0077] [Modified version of the second embodiment] In the transfer step (X) of the second embodiment, laser light may be irradiated from the substrate 61 side to transfer and arrange individual pieces of the anisotropic conductive film 70 in electrode units of the light-emitting element. That is, the method for manufacturing a connection structure according to a modified example of the second embodiment further includes a transfer step in which a connection film provided on a substrate that is transparent to laser light is placed opposite a wiring board, and laser light is irradiated from the substrate side to transfer individual pieces of the connection film onto the wiring board in electrode units, and in the impact step, chip components are impacted onto the individual pieces of the corresponding electrodes.

[0078] This makes it possible to suppress the occurrence of a short circuit between the first conductivity electrode 22 and the second conductivity electrode 23 in a light-emitting element 20 having a horizontal structure in which the first conductivity electrode 22 and the second conductivity electrode 23 are arranged on the same plane.

[0079] The following describes the transfer process (X-1) in which individual pieces of anisotropic conductive film are transferred to predetermined positions on the wiring substrate and arranged, the impact process (A2-1) in which light-emitting elements are projected onto the individual pieces of anisotropic conductive film by irradiating them with laser light, and the connection process (B2-1) in which light-emitting elements are connected to the wiring substrate. Components identical to those in the second embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0080] [Transfer process (X-1)] First, in the transfer process (X-1), as in the second embodiment and the transfer process (X), the anisotropic conductive film substrate 60 and the wiring substrate 30 are placed facing each other, as shown in Figure 5.

[0081] Figure 10 is a schematic cross-sectional view showing the state in which individual pieces of anisotropic conductive film are transferred onto the wiring board in electrode units and arranged by irradiating them with laser light from the substrate side. As shown in Figure 10, in the transfer process (X-1), laser light is irradiated from the substrate 61 side, and individual pieces 72 and 73 of the anisotropic conductive film 70 are transferred onto the wiring board 30 in electrode units and arranged.

[0082] In the transfer process (X-1), individual pieces 72 and 73 of the anisotropic conductive film 70 are transferred and arranged onto the first electrode 32 and the second electrode 33, which correspond to the first conductivity type electrode 22 and the second conductivity type electrode 23 of the light-emitting element 20, respectively. By transferring and arranging the individual pieces 72 and 73 only onto the first electrode 32 and the second electrode 33, it is possible to suppress the occurrence of a short circuit between the first conductivity type electrode 22 and the second conductivity type electrode 23.

[0083] The same lifting device as described above can be used to transfer the individual pieces 72 and 73 of the anisotropic conductive film 70, allowing the individual pieces 72 and 73 of the anisotropic conductive film 70 to be transferred and arranged on the wiring board 30 in electrode units with high precision and efficiency, thereby shortening the cycle time.

[0084] The reaction rate of the individual pieces 72 and 73 of the anisotropic conductive film 70 after the transfer step (X-1) is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, similar to the second embodiment and the transfer step (X). A reaction rate of 25% or less for the individual pieces 70a makes it possible to thermocompression bond the light-emitting element in the connection step (B2-1). The reaction rate can be determined, for example, using FT-IR.

[0085] [Impact process (A2-1)] Figure 11 is a schematic cross-sectional view showing a state in which a light-emitting element provided on a substrate is facing individual pieces transferred and arranged on a wiring board in electrode units. Figure 12 is a schematic cross-sectional view showing a state in which laser light is irradiated from the substrate side, causing the light-emitting element to hit the individual pieces on the corresponding electrodes and arrange them.

[0086] As shown in Figure 11, first, in the impact step (A2-1), the chip component substrate 10 and the wiring substrate 30 are placed facing each other, and the individual pieces 72 and 73 transferred onto the first electrode 32 and the second electrode 33, respectively, are aligned with the first conductivity type electrode 22 and the second conductivity type electrode 23 of the light-emitting element 20 provided on the chip component substrate 10. Then, as shown in Figure 12, laser light is irradiated from the substrate 11 side to impact the light-emitting element 20 onto the individual pieces 72 and 73 on the corresponding electrodes. For the transfer of the light-emitting element 20, a lift device can be used, for example, as in the first embodiment.

[0087] [Connection process (B2-1)] Figure 13 is a schematic cross-sectional view showing the state in which light-emitting elements are mounted on individual pieces of a wiring board. As shown in Figure 13, in the connection step (B2-1), the light-emitting elements 20 transferred to the wiring board 30 are mounted. The method for thermocompressing the light-emitting elements 20 to the wiring board 30 is the same as in the first embodiment.

[0088] According to the manufacturing method of the connecting structure relating to the second embodiment, the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. This suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of chip components in the impact process (A22-1), and enables the transfer and arrangement of chip components with high precision and efficiency, thereby shortening the cycle time.

[0089] Furthermore, since there is no anisotropic conductive film between the first conductivity type electrode 22 and the second conductivity type electrode 23 of the light-emitting element 20, and the wiring board 30 is exposed, the light-emitting element 20 can be anisotropically connected on the wiring board 30. This suppresses the occurrence of short circuits compared to when individual pieces of anisotropic conductive film are attached across the first conductivity type electrode 22 and the second conductivity type electrode 23.

[0090] [Third Embodiment] In the second embodiment, laser light was used to transfer individual pieces of the connecting film to predetermined positions on the wiring board, but the connecting film may also be provided on the electrodes of the chip components in advance.

[0091] In other words, the manufacturing method of the connection structure according to the third embodiment comprises a contact step in which a connection film on the electrode surface of a chip component provided on a substrate that is transparent to laser light is placed opposite a wiring board, and laser light is irradiated from the substrate side to cause the chip component to land on the wiring board via the connection film, and a connection step in which the chip component and the wiring board are connected, wherein the connection film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz.

[0092] As a result, similar to the first embodiment, defects such as misalignment, deformation, breakage, and detachment of chip components are suppressed during the impact process, and chip components can be transferred and arranged with high precision and efficiency, thereby shortening the cycle time.

[0093] The following describes the impaction step (A3), in which laser light is irradiated to impact the light-emitting element onto individual pieces of the anisotropic conductive film, and the connection step (B3), in which the light-emitting element is connected to the wiring board, with reference to Figure 14. Components identical to those in the first and second embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0094] [Impact Process (A3)] Figure 14 is a schematic cross-sectional view showing a state in which a connecting film provided on the electrode surface of a light-emitting element and a wiring board are facing each other. As shown in Figure 14, first, in the impact step (A3), the chip component substrate 10 and the wiring board 30 are facing each other. An anisotropic conductive film 80 is provided on the electrode surface of the light-emitting element 20, and the distance between the anisotropic conductive film 80 and the wiring board 30 is, for example, 10 to 100 μm.

[0095] The method for providing the anisotropic conductive film 80 on the electrode surface of the light-emitting element 20 is not particularly limited, but for example, as in the transfer step (X) of the second embodiment, the anisotropic conductive film provided on a substrate that is transparent to laser light and the electrode surface of the light-emitting element may be placed facing each other, and laser light may be irradiated from the substrate side to transfer individual pieces of the anisotropic conductive film onto the electrode surface of the light-emitting element.

[0096] Next, laser light is irradiated from the substrate 11 side to transfer the light-emitting elements 20 to the wiring substrate 30 via the anisotropic conductive film 80 and arrange them. Similar to the first embodiment, a lift device can be used to transfer the light-emitting elements 20.

[0097] [Connection process (B3)] In the connection step (B3), the light-emitting elements 20 arranged at predetermined positions on the wiring board 30 are mounted. The method for thermocompressing the light-emitting elements 20 to the wiring board 30 is the same as in the first embodiment.

[0098] According to the manufacturing method of the connecting structure of the third embodiment, the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz. This suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of chip components in the impact process (A3), and enables the transfer and arrangement of chip components with high precision and efficiency, thereby shortening the cycle time.

[0099] Furthermore, since there is no anisotropic conductive film between the light-emitting elements 20 and the wiring substrate 30 is exposed, the light-emitting elements 20 can be anisotropically connected on the wiring substrate 30. By using a light-transmitting substrate for the wiring substrate 30, superior light transmittance can be obtained compared to the case where an anisotropic conductive film is attached to the entire surface of the wiring substrate 30. [Examples]

[0100] <3. First Example> In the first embodiment, a chip component provided on quartz glass and a connecting film on a glass substrate were placed facing each other, and a laser beam was irradiated from the substrate side to cause the chip component to land on the connecting film. However, this embodiment is not limited to this one.

[0101] [Fabrication of connecting film] The following materials were prepared. Phenoxy resin (product name: PKHH, manufactured by Tomoe Chemical Industry Co., Ltd.) High-purity bisphenol A type epoxy resin (product name: YL-980, manufactured by Mitsubishi Chemical Corporation) Hydrophobic silica (product name: R202, manufactured by Nippon Aerosil Co., Ltd.) Acrylic rubber (product name: SG80H, manufactured by Nagase ChemteX Corporation) Cationic polymerization initiator (product name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.) Silicone rubber (Product name: STP-106T-UV, manufactured by Shin-Etsu Silicone Co., Ltd.) Conductive particles (average particle size 2.2 μm, resin core metal coated fine particles, 0.2 μm thick Ni plating, manufactured by Sekisui Chemical Co., Ltd.)

[0102] As shown in Table 2, each material was mixed in predetermined mass parts, and a resin layer of predetermined thickness was prepared on a glass substrate with a thickness of 0.5 mm. Conductive particles were extracted from the obtained resin layer using the method described in Japanese Patent No. 6187665, such that the conductive particles substantially coincided with one interface of the resin layer, and the particle surface density was 58,000 pcs / mm². 2 The connecting films 1 to 5 were fabricated by aligning them in this manner. Connecting film 6 was made by coating a glass substrate with silicone rubber and UV curing it. Connecting film 7 was made by thermoforming an acrylic rubber onto a glass substrate.

[0103] [Measurement of rubber hardness of connecting film] The rubber hardness (Japanese Industrial Standard JIS-A hardness) was measured using a durometer A in accordance with JIS K 6253.

[0104] [Measurement of the storage modulus of the connecting film] Dynamic viscoelasticity tests were performed using an indentation test apparatus (KLA iMicro nanoindenter). A flat punch with a diameter of 100 μm was used, with a target indentation depth of 1 μm. The storage modulus was measured at a temperature of 30°C and a frequency of 200 Hz by sweeping in the frequency range of 1 to 200 Hz. The Poisson's ratio of each sample was set to 0.5, and the average value of 12 measurement points for each sample was calculated.

[0105] [Measurement of the storage modulus of the connecting film after curing] The storage modulus of the cured connecting film was measured in tensile mode at a temperature of 30°C using a viscoelasticity tester (Vibron) in accordance with JIS K7244. The measurement conditions were a frequency of 11 Hz and a heating rate of 3°C / min.

[0106] [Table 2]

[0107] [Transferring chip components] Using a listing device (MT-30C200), chip components mounted on quartz glass were projected onto a connecting film on a glass substrate. For the chip components (outer dimensions 30 × 50 μm, thickness 5 μm), a TEG (Test Element Group) was used, with a release material (polyimide) placed between the quartz glass and the chip component.

[0108] As described above, the list device comprises a telescope that converts pulsed laser light emitted from a laser device into parallel light, a shaping optical system that uniformly shapes the spatial intensity distribution of the pulsed laser light that has passed through the telescope, a mask that allows the pulsed laser light shaped by the shaping optical system to pass through in a predetermined pattern, a field lens positioned between the shaping optical system and the mask, and a projection lens that reduces and projects the laser light that has passed through the pattern on the mask onto the donor substrate. The donor substrate is a quartz substrate with chip components held in place by a release material, which is held on the donor stage, and a receptor substrate is a glass substrate with a connecting film attached, which is held on the receptor stage, with a distance of 100 μm between the chip components and the connecting film.

[0109] The laser device used was an excimer laser with an oscillation wavelength of 248 nm. The pulse energy of the laser light was 600 J, and the fluence was 150 J / cm². 2 The pulse width (irradiation time) was 30,000 picoseconds, the pulse frequency was 0.01 kHz, and the number of irradiation pulses was 1 pulse per ACF1 piece. The pulse energy of the imaged laser light irradiated at the interface between the anisotropic conductive adhesive layer and the substrate was 0.001 to 2 J, and the fluence was 0.001 to 2 J / cm². 2 The pulse width (irradiation time) is 0.01 to 1 × 10⁻⁶. 9 The pulse duration was picosecond, the pulse frequency ranged from 0.1 to 10,000 Hz, and the number of pulses ranged from 1 to 30,000,000.

[0110] The mask used a pattern in which windows of a predetermined size were arranged at a predetermined pitch so that the projection at the interface between the quartz glass donor substrate and the release material would have an outer shape of 30 × 50 μm for the chip component.

[0111] [Evaluation of elasticity] Table 3 shows the evaluation results for chip component transfer on connecting films 1 to 7. A total of 100 chip components were transferred to the connecting films, and the number of chip components that landed successfully on the connecting films was counted using a microscope. The landing elasticity was evaluated with a rating from A to D below, depending on the percentage of chip components that landed successfully. A rating of C or higher is desirable. A: 100% B: 98% or more, less than 100% C: 90% to less than 98% D: Less than 90%

[0112] [Table 3]

[0113] As shown in Table 3, the durometer A hardness of connecting film 4 was too high, and the durometer A hardness of connecting film 5 was too low, resulting in a chip component transfer rate of less than 90%. On the other hand, connecting films 1-3, 6, and 7 had durometer A hardness of 20-40 and a storage modulus of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz, which allowed for a chip component transfer rate of 90% or more.

[0114] <5. Second Example> In the second embodiment, the chip component and the wiring board were heat-pressed together using the connecting films 1 to 7 of the first embodiment. However, this embodiment is not limited to these.

[0115] [Creating connection structures] Similar to the first embodiment, chip components were deposited onto a connection film on a wiring board, and a connection structure was fabricated by thermocompression bonding under the conditions of 150°C, 30 MPa, and 30 sec. For the chip components (outer dimensions 50 μm × 50 μm, thickness 150 μm), a TEG (Test Element Group) with a pair of electrodes (Cr / Au-plated bump 10 μm × 10 μm) was used. For the wiring board, a glass substrate (thickness 0.5 mm, Ti / Al / Ti pattern 10 μm × 10 μm) was used.

[0116] [Evaluation of conductivity] Table 4 shows the results of the conductivity evaluation for connecting films 1 to 7.

[0117] The continuity resistance was measured through the conductive wiring on the circuit board. The continuity was evaluated using a rating system from A to D based on the resistance value. A rating of C or higher is desirable. A: 50Ω or less B: More than 50Ω and less than 100Ω C: More than 100Ω and less than 200Ω D: Over 200Ω

[0118] [Table 4]

[0119] As shown in Table 4, connecting films 6 and 7 are not thermosetting, resulting in poor conductivity, and measures such as providing connection points like solder bumps on the chip components are necessary. On the other hand, connecting films 1 to 5 had storage moduli of over 2000 MPa, exceeding 100 MPa when measured in tensile mode after curing, and were able to achieve good conductivity. [Explanation of symbols]

[0120] 10 Chip component substrate, 11 Base material, 12 Release material, 20 Light-emitting element, 21 Main body, 22 First conductive electrode, 23 Second conductive electrode, 30 Wiring board, 31 Base material, 32 First electrode, 33 Second electrode, 40 Anisotropic conductive film, 50 Laser light, 60 Anisotropic conductive film substrate, 61 Base material, 70 Anisotropic conductive film, 70a Piece, 72 Piece, 73 Piece, 80 Anisotropic conductive film, 101 LED, 102 Transfer material, 103 Stamp material, 104 Panel substrate, 105 Connecting film, 111 LED, 112 Transfer material, 113 Release material, 114 Panel substrate, 115 Connecting film

Claims

1. It contains rubber components, has a durometer A hardness of 20 to 40, and its storage modulus is 60 MPa or less in a dynamic viscoelasticity test using an indentation test device at a temperature of 30°C and a frequency of 200 Hz. A connecting film for impacting chip components onto a substrate using laser light irradiation.

2. The connecting film according to claim 1, further comprising a film-forming resin, a thermosetting resin, a curing agent, and an inorganic filler, wherein the storage modulus at a temperature of 30°C measured in tensile mode in accordance with JIS K7244 after curing is 0.1 GPa or more.

3. The connecting film according to claim 2, further containing conductive particles, wherein the conductive particles are arranged in a planar direction.

4. The connecting film according to any one of claims 1 to 3, wherein the rubber component is one or more selected from acrylic rubber and silicone rubber.

5. The thermosetting resin contains an epoxy compound, The connecting film according to any one of claims 2 to 4, wherein the curing agent is a cationic polymerization initiator.

6. The amount of the rubber component is 2 to 10 parts by mass per 100 parts by mass of the total of the film-forming resin, the thermosetting resin, the curing agent, the inorganic filler, and the rubber component. The connecting film according to any one of claims 2 to 5, wherein the amount of the inorganic filler is 8 to 12 parts by mass with respect to 100 parts by mass of the total of the film-forming resin, the thermosetting resin, the curing agent, the inorganic filler, and the rubber component.

7. The connecting film according to any one of claims 1 to 6 and A substrate that is transparent to laser light and A connecting film substrate comprising a film substrate.

8. The connecting film substrate according to claim 7, further comprising a release material between the connecting film and the substrate.

9. A chip component provided on a substrate that is transparent to laser light and a connecting film on a wiring board are placed facing each other, and a laser beam is irradiated from the substrate side to cause the chip component to land on the connecting film; The process includes a connection step of connecting the chip component and the wiring board, A method for manufacturing a connecting structure, wherein the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz.

10. The invention further comprises a transfer step in which a connecting film provided on a substrate that is transparent to laser light is placed opposite a wiring board, and laser light is irradiated from the substrate side to transfer individual pieces of the connecting film onto the wiring board. The method for manufacturing a connecting structure according to claim 9, wherein in the projectile impact step, the chip component is projected onto an individual piece of the connecting film.

11. The invention further comprises a transfer step in which a connecting film provided on a substrate that is transparent to laser light is placed opposite a wiring board, and laser light is irradiated from the substrate side to transfer individual pieces of the connecting film onto the wiring board in electrode units, The method for manufacturing a connection structure according to claim 9, wherein the impact step involves impacting the chip component onto a corresponding electrode piece.

12. A projectile impact step involves placing a connecting film on the electrode surface of a chip component, which is provided on a substrate that is transparent to laser light, against a wiring board, and irradiating the substrate with laser light to cause the chip component to land on the wiring board via the connecting film. The process includes a connection step of connecting the chip component and the wiring board, A method for manufacturing a connecting structure, wherein the connecting film contains a rubber component, has a durometer A hardness of 20 to 40, and has a storage modulus of elasticity of 60 MPa or less at a temperature of 30°C and a frequency of 200 Hz.

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