WO2017033545A1

WO2017033545A1 - Method for bonding two substrates and device for bonding two substrates

Info

Publication number: WO2017033545A1
Application number: PCT/JP2016/068227
Authority: WO
Inventors: 啓太吉原; 史敏竹元; 真和佐本; 鈴木　信二
Original assignee: ウシオ電機株式会社
Priority date: 2015-08-26
Filing date: 2016-06-20
Publication date: 2017-03-02
Also published as: TW201718271A

Abstract

The purpose of the present invention is to provide a method for bonding two substrates and a device for bonding two substrates, enabling a first substrate and a second substrate to bond via a functional film so as not to make direct contact with each other except for via the functional film. The method for bonding two substrates according to the present invention is for bonding, via a functional film having a specified peripheral shape, a second substrate and a first substrate having the functional film formed on the surface thereof, and is characterized by including: an ultraviolet ray irradiation step for irradiating, with ultraviolet rays under vacuum, the surface of the functional film formed on the surface of the first substrate; a stacking step for stacking the second substrate and the first substrate, which have undergone the ultraviolet ray irradiation step, such that the surface of the functional film and a bonding surface of the second substrate are in contact with each other; and a pressure application step for applying, in the thickness direction, pressure on a stacked body of the first substrate and the second substrate obtained through the stacking step such that pressure is applied selectively on the portion where the functional film and the second substrate make contact with each other.

Description

Method for bonding two substrates and apparatus for bonding two substrates

The present invention relates to a method for bonding two substrates and a bonding apparatus for two substrates, and more specifically, a first substrate and a second substrate each having a functional film having a defined outer shape formed on the surface. The present invention relates to a method for laminating a substrate and a laminating apparatus for two substrates.

In recent years, as a method of bonding two substrates, ultraviolet rays are irradiated on the bonding surfaces of the respective substrates, and the two substrates are stacked and bonded so that the ultraviolet irradiation surfaces are in close contact with each other. A technique for obtaining a joined body has been proposed (see, for example, Patent Document 1 and Patent Document 2). In the method of bonding the two substrates, the stacked body of the two substrates may be appropriately pressurized, heated, or heated while being pressurized as necessary.

Specifically, Patent Document 1 includes a hydrophobic surface substrate having a surface on which an organosiloxy group exists such as a polydimethylsiloxane (PDMS) substrate and a hydrophilic surface substrate having a surface on which a hydroxyl group exists. A method of matching is disclosed. In this method, the surface on which the organosiloxy group is present on the hydrophobic surface substrate is subjected to an oxidation treatment by irradiating it with vacuum ultraviolet rays (ultraviolet rays having a wavelength of 220 nm or less) in the atmosphere, and this oxidized hydrophobic property is obtained. The hydrophobic surface substrate and the hydrophilic surface substrate are bonded together by bringing the surface of the hydrophilic surface substrate on which the hydroxyl group exists into close contact with the surface of the surface substrate.

Patent Document 2 discloses a method of bonding a plurality of microchip substrates made of a resin such as cycloolefin polymer (COP). In this method, after irradiating light from an excimer lamp having an emission line at a wavelength of 172 nm to the surface of at least one of the two resin substrates, both substrates are irradiated with light from the excimer lamp on one substrate. Are stacked so that the surface irradiated with and the bonding surface of the other substrate are in contact with each other, and the resulting stack is heated to a temperature lower than the composition deformation temperature or applied without heating. By pressing, two resin substrates are bonded together.

In these bonding methods using ultraviolet rays, one surface of each of the two substrates used for bonding is used as a bonding surface, and the entire bonding surfaces are bonded together.
However, the method of bonding the two substrates is not limited to the method of bonding the entire bonding surfaces together, for example, only a part of one of the surfaces (bonding surfaces) of each substrate. There has been proposed a method of bonding two substrates using as a bonding region (see, for example, Patent Document 3).
Specifically, in Patent Document 3, a bonding film having a defined outer shape is formed on a bonding surface of at least one of two substrates, and two sheets are formed using the bonding film. A method of bonding the substrates is disclosed. In this method, two substrates are bonded together through a bonding process as shown in FIG.

FIG. 6 is an explanatory view showing an example of a bonding process in a conventional method for bonding two substrates, specifically, a bonding process in a method for bonding two substrates disclosed in Patent Document 3. It is explanatory drawing which shows an example.
In this method of bonding two substrates, first, two flat substrates, specifically, a first substrate 40 and a second substrate 45 are prepared. On the bonding surface of one of these two substrates, a bonding film 43 having a prescribed outer shape is formed of a silicone material. The bonding film 43 can be formed by using, for example, an ink jet printer. The average thickness of the bonding film 43 is, for example, 10 nm to 10 μm.
In the example of this figure, a bonding film 43 is formed on the bonding surface of the first substrate 40.

Then, as shown in FIGS. 6A-1 and 6A-2, a bonding surface (upper surface in FIG. 6A-1) on which the bonding film 43 is formed on the first substrate 40 and Ultraviolet rays L3 and L4 are respectively irradiated on the bonding surface (the upper surface in FIG. 6A-2) of the second substrate 45 (ultraviolet irradiation process step). Here, the wavelengths of the ultraviolet rays L3 and L4 are, for example, 126 to 300 nm.
Next, as shown in FIG. 6B, the surface of the bonding film 43 irradiated with the ultraviolet ray L3 in the first substrate 40 and the bonding surface of the second substrate 45 irradiated with the ultraviolet ray L4 are in close contact with each other. As described above, the first substrate 40 and the second substrate 45 are stacked (stacking step).
Thereafter, as shown in FIG. 6C, the stack of the first substrate 40 and the second substrate 45 is added in the thickness direction (the direction in which the first substrate 40 and the second substrate 45 approach each other). Pressure (pressurizing step). Here, the pressure applied to the stack is, for example, about 0.2 to 10 MPa. Instead of pressurizing the stack, the stack may be heated. In this case, the heating temperature is, for example, about 25 to 100 ° C.
In FIG. 6C, the pressing direction of the stacked body of the first substrate 40 and the second substrate 45 is indicated by an arrow.

In such a method of bonding two substrates, the two substrates are bonded via a bonding film. According to this method, the bonding strength of the two substrates can be appropriately controlled by the surface area of the bonding film, the number of bonding films formed, and the arrangement pattern of the plurality of bonding films. For example, the bonding strength can be set so that two bonded substrates can be easily separated.

Japanese Patent No. 3714338 JP 2006-187730 A JP 2009-132749 A

On the other hand, a bonded body in which two substrates are bonded together through a bonding film may require an optical function in addition to a function that contributes to simple bonding depending on the intended use. Specific examples include constituent members of a surface light source unit used as a backlight of a display, for example.

As shown in FIG. 7, a certain type of surface-emitting light source unit includes a light source 51 composed of LEDs and lamps, a rectangular plate-shaped light guide plate 61, and a rectangular flat plate disposed on the lower surface of the light guide plate 61. And a reflector 63 in the form of a plate.
In the example of this figure, the surface-emitting light source unit includes a plurality of light sources 51, and the plurality of light sources 51 are made of LEDs. The plurality of light sources 51 are arranged side by side at equal intervals along one side surface 61a (one end surface) of the light guide plate 61 so that each of the light sources 51 faces the side surface 61a.

In this surface-emitting light source unit, the light guide plate 61 is a light-transmitting substrate made of light-transmitting resin such as COP (cycloolefin polymer) and acrylic resin, glass or the like. The light from the light source 51 is incident on the light guide plate 61 on the side surface 61 a facing the light source 51. The light guide plate 61 is designed to totally reflect light from the light source 51 introduced from the side surface 61a at the interface between the light guide plate 61 and air. That is, in the light guide plate 61, light introduced into the inside from the side surface (specifically, the side surface 61a) constituting one end surface is extracted from the side surface (specifically, the side surface 61b) constituting the other end surface. It is said that.
In FIG. 7A, the optical path of the light emitted from the light source 51 and incident from the side surface 61a and introduced into the light guide plate 61 is indicated by a dashed arrow.

Further, a diffusion member layer 66 and a reflection plate 63 are provided in this order on the lower surface of the light guide plate 61.
The diffusion member layer 66 is made of a material having a refractive index substantially equal to the refractive index of the light guide plate 61 (specifically, for example, epoxy resin, polyester resin, PMMA (polymethyl methacrylate) resin). The diffusion member layer 66 is formed on the lower surface of the light guide plate 61 by screen printing or the like.
The reflecting plate 63 is a reflecting member made of aluminum or the like and having an upper surface as a reflecting surface.
In the example of this figure, the diffusing member layer 66 has a pattern.

In the surface-emitting light source unit having such a configuration, light from the light source 51 incident from the side surface 61 a and introduced into the light guide plate 61 is emitted from the upper surface of the light guide body 61.
More specifically, as described above, the light guide plate 61 is configured such that light incident on the side surface (side surface 61a) constituting one end surface of the light guide plate 61 repeats total reflection inside the light guide plate 61, and so on. It is designed to be emitted from the side surface (side surface 61b) constituting the end surface. However, among the light from the light source 51 introduced into the light guide plate 61, most of the light incident on the interface between the light guide plate 61 and the diffusing member layer 66 has substantially the same refractive index. Since the difference in refractive index is small, it passes through this interface as it is and reaches the reflector 63. Then, the light that reaches the reflection plate 63 is reflected and scattered, enters the diffusion member layer 66 and the light guide plate 61 again, and returns to the inside of the diffusion member layer 66 and the light guide plate 61. Of the reflected / scattered light, light incident on the light guide plate 61 in a state different from the total reflection condition of the light guide plate 61 is not totally reflected on the upper surface of the light guide plate 61 and is emitted from the upper surface of the light guide plate 61. Is done. That is, the surface-emitting light source unit of FIG. 7 functions as a surface-emitting light source that emits light from the entire upper surface of the light guide plate 61.
In FIG. 7A, the optical path of the reflected / scattered light that has reached the reflecting plate 63 and is reflected / scattered is indicated by a solid line arrow.

A member (hereinafter, also referred to as “light emitting surface forming member”) having a diffusion member layer interposed between a light guide plate and a reflecting plate, which constitutes such a surface light source unit, is a surface (bonding surface). It is obtained by pasting together a reflection plate having a diffusion member layer formed thereon and a light guide plate. The light emitting surface forming member can be obtained by the method for bonding two substrates disclosed in Patent Document 3 described above. In this case, the reflection plate is the first substrate, the diffusion member layer is the bonding film, and the light guide plate is the second substrate.
Thus, in the light emitting surface forming member, the diffusion member layer is required to have an optical function as well as a function contributing to bonding.

However, in the case where a bonded body in which two substrates are bonded together through a bonding film is one in which an optical function is required for the bonding film, the two substrates disclosed in Patent Document 3 Depending on the bonding method, it is not possible to obtain the desired bonded body. The reason will be described below.

In the method for bonding two substrates disclosed in Patent Document 3, for example, a pressurizing mechanism as shown in FIG. 8 is provided for pressurization of the stack of the first substrate and the second substrate. An apparatus for bonding two substrates is used.
FIG. 8 is an explanatory diagram showing an example of the configuration of a pressure mechanism in a conventional two-substrate bonding apparatus, that is, a pressure mechanism used in a conventional two-layer bonding method. Fig. 6 is an embodiment of the pressurization step shown in Fig. 6 (c) in the method of bonding two substrates disclosed in Patent Document 3.
This pressurizing mechanism includes a rectangular plate-like stage 73 on which a substrate is placed and a rectangular flat plate-like pressurizing plate 71. The stage 73 has a flat substrate mounting surface 73A. The pressure plate 71 is provided so as to be movable in the vertical direction on the substrate placement surface 73A.
In the pressurizing process of the stacked body by the pressurizing mechanism, for example, the stacked body is mounted on the substrate mounting surface 73A of the stage 73 so that one substrate side (the first substrate 40 side) faces downward. In the placed state, the pressing is performed by the pressure plate 71 from the other substrate side (second substrate 45 side).
Therefore, when the second substrate 45 is larger in deformability than the first substrate 40, specifically, for example, the constituent material of the second substrate 45 is the constituent material of the first substrate 40. 9A, the second substrate 45 (the bonding surface of the second substrate 45) is deformed in the pressurizing step, as shown in FIG. In the peripheral region of 43, the first substrate 40 and the second substrate 45 are in direct contact without the bonding film 43 interposed therebetween. In many cases, the first substrate 40 and the second substrate 45 are bonded as they are.
Further, when the first substrate 40 is larger in deformability than the second substrate 45, specifically, for example, the constituent material of the first substrate 40 is the constituent material of the second substrate 45. 9B, the first substrate 40 (the bonding surface of the first substrate 40) is deformed in the pressurizing process, as shown in FIG. In the peripheral region of 43, the first substrate 40 and the second substrate 45 are in direct contact without the bonding film 43 interposed therebetween. In many cases, the first substrate 40 and the second substrate 45 are bonded as they are.

Thus, when the light-emitting surface forming member of the surface-emitting light source unit is produced by the method of bonding two substrates disclosed in Patent Document 3, as shown in FIG. The (second substrate 45) and the reflector (first substrate 40) are partly, specifically in the peripheral region of the diffusion member layer (bonding film 43), with the diffusion member layer (bonding film 43) interposed therebetween. Contact directly without touching. That is, in the obtained light emitting surface forming member, the light guide plate (second substrate 45) and the reflection plate (first substrate 40) have an undesired direct contact region 49. In the direct contact region 49, light incident on the interface between the light guide plate (second substrate 45) and the reflection plate (first substrate 40) is scattered in an undesired direction as stray light. Therefore, the light that is reflected and scattered by the reflecting plate (first substrate 40) and emitted from the upper surface of the light guide plate (second substrate 45) has an intensity distribution different from the predetermined intensity distribution due to the influence of the stray light. It will have.

The present invention has been made based on the above circumstances, and its purpose is to function the first substrate and the second substrate so that they do not directly contact each other without the functional film. An object of the present invention is to provide a method for bonding two substrates and a bonding apparatus for two substrates that can be bonded together through a conductive film.

In the method for laminating two substrates of the present invention, the first substrate and the second substrate on which the functional film having a defined outer shape is formed are bonded via the functional film. A method of bonding two substrates,
A surface activation step for activating the surface of the functional film formed on the surface of the first substrate;
Stacking the first substrate and the second substrate that have passed through the surface activation step so that the surface of the functional film and the bonding surface of the second substrate are in contact with each other. And a stack of the first substrate and the second substrate obtained in the stacking step is selectively applied to a contact portion between the functional film and the second substrate. Thus, a pressurizing step of pressurizing in the thickness direction is included.

In the method for laminating two substrates of the present invention, the pressing step uses a pressing plate having a protruding portion having a shape corresponding to the functional film formed on the surface of the first substrate. It is preferably performed by pressing the pressure plate in a state where the protrusion is positioned so as to face the functional film via the first substrate or the second substrate.
In such a method for bonding two substrates of the present invention, a substrate having a small deformability among the first substrate and the second substrate is in contact with the pressure plate. Is preferred.

In the two-layer bonding method of the present invention, the ultraviolet ray is irradiated on the bonding surface of the second substrate that is subjected to the stacking step, or a process gas that is made plasma by atmospheric plasma is brought into contact with the bonding surface. It is preferable.

In the method for laminating two substrates of the present invention, the surface activation step is an ultraviolet irradiation process for irradiating the surface of the functional film formed on the surface of the first substrate with vacuum ultraviolet rays. It is preferable.

In the method for laminating two substrates of the present invention, the surface activation step is performed by applying a process gas plasmatized by atmospheric pressure plasma to the surface of the functional film formed on the surface of the first substrate. It is preferable that it is a plasma gas treatment process to contact.

The apparatus for bonding two substrates of the present invention bonds a first substrate having a functional film having a defined outer shape on the surface and a second substrate through the functional film. An apparatus for laminating two substrates for
A pressurizing mechanism is provided for pressurizing the stack in a thickness direction in a state where the surface of the functional film of the first substrate and the bonding surface of the second substrate are in contact with each other;
The pressure mechanism includes a pressure plate having a protrusion having a shape corresponding to a functional film formed on the surface of the first substrate, and an alignment adjusting unit between the pressure plate and the stack. The method is characterized in that a pressing force is selectively applied to a contact portion between the functional film and the second substrate.

In the method for laminating two substrates of the present invention, the first substrate and the second substrate are formed on the surface of the first substrate in the pressurizing step of pressurizing the stack of the second substrate in the thickness direction. A pressing force selectively acts on a contact portion between the functional film and the second substrate. Therefore, even if one of the first substrate and the second substrate has greater deformability than the other, the periphery of the functional film is bonded to the bonding surface of the first substrate and the second substrate. It is possible to prevent or sufficiently suppress the deformation in which the first substrate and the second substrate are in direct contact with each other without the functional film interposed therebetween in the region.
Therefore, according to the method for bonding two substrates of the present invention, the first substrate and the second substrate are bonded via the functional film so that they are not in direct contact without the functional film. Can be matched.

In the bonding apparatus for two substrates of the present invention, a pressure plate having a protrusion having a shape corresponding to the functional film formed on the surface of the first substrate, and the positions of the pressure plate and the stack A pressurizing mechanism provided with an alignment adjusting means is provided. And a pressurization mechanism is with respect to the contact part of the said functional film and the said 2nd board | substrate with respect to the stack of the 1st board | substrate with which the functional film was formed on the surface, and the 2nd board | substrate. Thus, the pressure can be selectively applied. For this reason, the first substrate and the second substrate are pressed by an easy method of pressing the stack in a state in which the surface of the functional film of the first substrate and the bonding surface of the second substrate are in contact with each other. A substrate can be attached. As a result, even if one of the first substrate and the second substrate has a larger deformability than the other, the functional film is formed on the bonding surface of the first substrate and the second substrate. It is possible to prevent or sufficiently suppress the deformation in which the first substrate and the second substrate are in direct contact with each other without passing through the functional film in the peripheral region.
Therefore, according to the bonding apparatus for two substrates of the present invention, the first substrate and the second substrate are bonded via the functional film so as not to be in direct contact without the functional film. Can be matched.

It is explanatory drawing which shows an example of the bonding process of the bonding method of the 2 board | substrate of this invention. It is sectional drawing for description which shows the structure in an example of the atmospheric pressure plasma apparatus used for the bonding method of the 2 board | substrate of this invention. It is explanatory drawing which shows an example of the conjugate | zygote obtained in the bonding method of 2 sheets of this invention with the pressurization mechanism in an example of the bonding apparatus of 2 sheets of this invention. It is explanatory drawing which shows the other example of the bonding process of the bonding method of the 2 board | substrate of this invention. It is explanatory drawing which shows the joining area | region of the conjugate | zygote obtained in Experimental example 1, Experimental example 2, and Experimental example 3. FIG. It is explanatory drawing which shows an example of the bonding process in the conventional bonding method of two board | substrates. It is explanatory drawing which shows an example of a structure of the conventional surface emitting light source unit, (a) is a side view of a surface emitting light source unit, (b) is an A direction arrow directional view of (a). It is explanatory drawing which shows an example of a structure of the pressurization mechanism in the conventional bonding apparatus of two board | substrates. It is explanatory drawing which shows the joined body obtained by the bonding method of the conventional 2 board | substrate.

Hereinafter, embodiments of the method for bonding two substrates and the apparatus for bonding two substrates of the present invention will be described.

The method for laminating two substrates of the present invention comprises the steps of (1) to (3) below, and the first substrate having a functional film having a defined outer shape formed on the surface: The second substrate is bonded and bonded through the functional film. According to the method for bonding two substrates of the present invention, a joined body is obtained in which the first substrate and the second substrate are joined via the functional film.
Here, the “functional film” has a function (bonding function) that contributes to the bonding of at least two substrates. Specifically, the “functional film” is used for use of the obtained bonded body, if necessary. Accordingly, it has functions other than the bonding function such as an optical function as well as the bonding function. As long as the functional film has a bonding function, the functional film may not have other functions (functions other than the bonding function). The constituent material of the functional film is appropriately selected according to the function required for the functional film, the constituent material of the first substrate, the constituent material of the second substrate, and the like. Specific examples include polydimethylsiloxane (PDMS) and PET (polyethylene terephthalate) resin.

(1) Surface activation step for activating the surface of the functional film formed on the surface of the first substrate (2) The first substrate and the second substrate that have passed through the surface activation step are functioned Stacking step (3) in which the surface of the conductive film and the bonding surface of the second substrate are in contact with each other, and (3) the first substrate and the second substrate obtained in the stacking step Pressurizing step of pressurizing the stack in the thickness direction so that a pressing force selectively acts on a contact portion between the functional film and the second substrate

In the method for laminating two substrates of the present invention, the surface activation step is an ultraviolet irradiation treatment step of irradiating the surface of the functional film on the first substrate with vacuum ultraviolet rays, or a process that is made plasma by atmospheric pressure plasma. It is preferable that it is a plasma gas treatment process in which a gas is brought into contact with the surface of the functional film in the first substrate.

In the pressurizing step of the method for bonding two substrates of the invention, a stack of the first substrate and the second substrate is selected for the contact portion between the functional film and the second substrate. As a suitable method for applying the applied pressure, a method using a pressure plate having a protrusion having a shape corresponding to the functional film formed on the surface of the first substrate can be cited.
More specifically, the pressing step uses a pressure plate having a protrusion having a shape corresponding to the functional film formed on the first substrate, and the protrusion is the first substrate or the second substrate. It is preferably performed by pressing the pressure plate in a state of being positioned so as to face the functional film through the substrate. Such a method includes a pressure plate having a protrusion corresponding to the functional film formed on the first substrate, and an alignment adjustment unit between the pressure plate and the stack, It can be carried out by an apparatus provided with a pressurizing mechanism for selectively applying a pressing force to a contact portion between the functional film and the second substrate, that is, an apparatus for bonding two substrates of the present invention. .

In such a method, it is preferable that a substrate having a small deformability among the first substrate and the second substrate is in contact with the pressure plate.
Of the first substrate and the second substrate, the substrate having a small deformability is brought into contact with the pressure plate, so that either the first substrate or the second substrate is deformed in the pressing step. Will not occur. Therefore, in the obtained bonded body, peeling between the first substrate and the second substrate caused by the occurrence of residual stress can be suppressed.
On the other hand, when the highly deformable substrate of the first substrate and the second substrate is in contact with the pressure plate, the pressure plate (protrusion) is placed on the substrate in contact with the pressure plate. There is a possibility that a dent corresponding to the shape of the protruding portion is generated on the contact surface with the portion) and residual stress is generated. When the residual stress is generated, the first substrate and the second substrate may be easily peeled in the obtained bonded body.

In the method for bonding two substrates of the present invention, from the viewpoint of bonding efficiency, an ultraviolet irradiation process for irradiating vacuum ultraviolet light on the bonding surface of the second substrate to be subjected to the stacking step, or It is preferable to perform a plasma gas treatment in which a process gas converted into plasma by atmospheric plasma is brought into contact.

Preferred specific examples of the method for bonding two substrates of the present invention include a first bonding method and a second bonding method, which will be described later.
Which of the first bonding method and the second bonding method is used is appropriately selected according to the constituent material and thickness of the first substrate, the second constituent material and thickness, and the like.
Specifically, the second substrate is compared with the first substrate because, for example, the constituent material of the first substrate is softer or thinner than the constituent material of the second substrate. If the deformability is small, it is preferable to use the first bonding method. On the other hand, the first substrate can be compared with the second substrate because, for example, the constituent material of the second substrate is softer or thinner than the constituent material of the first substrate. In the case where the deformability is small, it is preferable to use the second bonding method.

The constituent materials of the two substrates (specifically, the first substrate and the second substrate) used in the method for bonding the two substrates of the present invention include PET (polyethylene terephthalate) resin, COP (Cycloolefin polymer) and acrylic resin (specifically, for example, PMMA (polymethyl methacrylate) resin), glass (specifically, for example, non-alkali glass), and the like.

[First bonding method]
Hereinafter, two embodiments of the first bonding method according to the bonding method of two substrates of the present invention will be described.

<First Embodiment of First Bonding Method>
A first embodiment of the first bonding method (hereinafter also referred to as “first bonding method (1)”) will be described in detail with reference to FIG.
In the first bonding method (1), the second substrate 15 is smaller in deformability than the first substrate 10, and specifically, for example, the first substrate 10 is PET. It is made of resin, and the second substrate 15 is made of COP, acrylic resin, or glass. The functional film 13 is made of PDMS. And the joined body obtained is a constituent member of a surface-emitting light source unit used as a backlight of a display, specifically, a light guide plate made of COP, acrylic resin or glass, a diffusion member layer made of PDMS, and PET A reflecting plate made of a resin is used as a light emitting surface forming member formed by laminating in this order. In this bonded body, the functional film 13 has an optical function as well as a function contributing to bonding.

In the first bonding method (1), the steps (1) to (3) described above are performed, and as shown in FIG. 1 (a-2), the surface of the second substrate 15 used for the stacking step An ultraviolet irradiation treatment is performed on the (bonding surface). In addition, as shown in FIG. 1 (e), the first bonding method (1) is performed in accordance with the use of the two substrate bonding apparatus of the present invention in the pressing step. -1), (b-2), (c) and (f), the first substrate 10 alignment adjustment processing, the pressure plate 21 alignment adjustment processing, and the pressure plate 21 retraction processing (temporary retraction processing). Including).
In the first bonding method (1), as shown in FIG. 1 (a-1), the surface activation process is an ultraviolet irradiation process.

In the bonding apparatus for two substrates of the present invention used in the first bonding method (1), the pressurizing mechanism is a substrate as shown in FIGS. 1 (b-1) to (f). (Specifically, a rectangular plate-like stage 23 on which the first substrate 10 and the second substrate 15 are placed, and a shape corresponding to the functional film 13 formed on the first substrate 10. And a pressure plate 21 having a protruding portion 22B. The stage 23 has a flat substrate placement surface 23A, and a plurality of (3 in the example of FIG. 1) extend perpendicularly from the substrate placement surface 23A at the peripheral portion of the substrate placement surface 23A. Book) positioning pins 25 are provided. The positioning pins 25 are alignment adjusting means having a positioning function with respect to the substrate and the pressure plate 21. That is, the positioning pin 25 constitutes an alignment adjusting means for the stacked body (specifically, the stacked body of the first substrate 10 and the second substrate 15) and the pressure plate 21. The pressure plate 21 has a protrusion 22B on the surface of the rectangular plate-like base material 22A (the lower surface in FIGS. 1C, 1D, 1E, and 1F). Then, the pressure plate 21 is such that the surface of the pressure plate 21 faces the substrate placement surface 23A and is positioned by the positioning pins 25, so that the protrusion 22B is placed on the substrate placement surface 23A. The functional film 13 formed on one substrate 10 is opposed to the functional film 13. The pressure plate 21 is provided to be movable in the vertical direction on the substrate placement surface 23A.
In the example shown in the figure, the pressure plate 21 has a base material 22A having the same vertical and horizontal dimensions as the first substrate 10 and the second substrate 15, and a protrusion height of 1 mm at the center of the base material 22A. The protrusion 22B is provided.

In the first bonding method (1), first, a rectangular flat plate-like first substrate 10 and a rectangular flat plate-like second substrate having a surface having a size suitable for the surface of the first substrate 10. 15 are prepared. Then, a functional film 13 having a prescribed outer shape is formed on the surface of the first substrate 10 by screen printing or the like. In the first substrate 10, the surface on which the functional film 13 is formed serves as a bonding surface with the second substrate 15. On the other hand, in the second substrate 15, the surface having a size suitable for the bonding surface of the first substrate 10 is the bonding surface with the first substrate 10.
In the example of this figure, a functional film 13 having a defined outer shape (specifically, a rectangular outer shape) and a thickness of 10 μm is formed on the first substrate 10 at the center of the bonding surface. ing.

(First step: first substrate surface activation step and second substrate ultraviolet irradiation treatment step)
In the first substrate surface activation process and the second substrate ultraviolet irradiation process, as shown in FIGS. 1 (a-1) and 1 (a-2), the bonding surface ( Vacuum ultraviolet rays (ultraviolet rays having a wavelength of 200 nm or less) L1, L2 on the bonding surface (upper surface in FIG. 1 (a-2)) of FIG. Irradiate.

Through the first substrate surface activation step, the bonding surface of the first substrate 10, specifically, the surface of the functional film 13 (the upper surface in FIG. 1A-1) is activated. And modified so that the surface is suitable for bonding. Specifically, the surface of the functional film 13 is hydrophilized in a state where, for example, a hydroxy group (OH group) exists. That is, the surface of the functional film 13 is terminated with a hydroxy group by introducing a hydroxy group derived from moisture in the atmosphere. In addition, the bonding surface of the first substrate 10 is cleaned by removing contaminants such as organic substances.

The second substrate ultraviolet irradiation treatment step is not necessarily a necessary step, but is preferably performed from the viewpoint of bonding efficiency.
More specifically, as long as the bonding surface of the first substrate 10 is irradiated with the vacuum ultraviolet rays L1, that is, even the surface of the functional film 13 is activated, the first substrate 10 and the second substrate 15 Can be joined. However, the bonded surface of the second substrate 15 is cleaned by removing contaminants such as organic substances on the bonded surface of the second substrate 15 through the second substrate ultraviolet irradiation process. As described above, when the bonding surface of the second substrate 15 is cleaned, the two substrates can be bonded efficiently.
Further, in the second substrate ultraviolet irradiation process, depending on the constituent material of the second substrate 15, the bonding surface of the second substrate 15 is activated to become a surface suitable for bonding. It is modified as follows. Specifically, the bonding surface of the second substrate 15 is hydrophilized in a state where, for example, a hydroxy group (OH group) exists. That is, the bonding surface of the second substrate 15 is terminated with a hydroxy group by introducing a hydroxy group derived from moisture in the atmosphere.

In the first substrate surface activation process and the second substrate ultraviolet irradiation process, the light source that emits the vacuum ultraviolet rays L1 and L2 is an excimer lamp such as a xenon excimer lamp having a bright line at a wavelength of 172 nm, and a wavelength of 185 nm. A low-pressure mercury lamp having an emission line and a deuterium lamp having an emission line in the wavelength range of 120 to 200 nm can be preferably used.
The illuminance of the vacuum ultraviolet rays L1 and L2 applied to the bonding surface of the first substrate 10 and the bonding surface of the second substrate 15 is, for example, 10 to 100 mW / cm ² .
The irradiation time of the vacuum ultraviolet rays L1 and L2 on each of the bonding surface of the first substrate 10 and the bonding surface of the second substrate 15 depends on the constituent material of the functional film 13 and the state of the surface of the functional film 13. Alternatively, it is set as appropriate depending on the constituent material of the second substrate 15 and the state of the bonding surface of the second substrate 15, but for example, 5 to 120 seconds.

(Second step: pressure plate alignment adjustment step)
In the pressure plate alignment adjustment step, as shown in FIGS. 1B-1 and 1B-2, the first substrate 10 is placed on the substrate placement surface 23A of the stage 23 in the pressure mechanism. In the state, alignment adjustment processing (positioning adjustment processing) of the pressure plate 21 is performed.
Specifically, first, in the state where the back surface (the lower surface in FIG. 1 (b-1)) of the first substrate 10 is in contact with the substrate mounting surface 23A of the stage 23, the peripheral side surface is made up of the plurality of positioning pins 25. The substrate is positioned by being abutted against all of the substrates, and is placed at a predetermined position on the substrate placement surface 23A. In this way, the alignment adjustment process for the first substrate 10 is performed. Next, in a state where the pressure plate 21 is opposed to the functional film 13 formed on the first substrate 10 placed on the substrate placement surface 23A with the surface having the protrusion 22B slightly spaced from the base plate 23B. Positioning is performed by abutting the peripheral side surface of the material 22 </ b> A against all of the plurality of positioning pins 25. In this way, the alignment adjustment process of the pressure plate 21 is performed. Thus, the protruding portion 22B of the pressure plate 21 is aligned so as to face the functional film 13 through the space.
FIG. 1B-1 shows a state in which the first substrate 10 is placed on the substrate placement surface 23A of the stage 23, and the pressure plate 21 is positioned and arranged above the first substrate 10. It is a side view for description. FIG. 1B-2 is an explanatory diagram showing the mounting state of the first substrate 10 on the substrate mounting surface 23A of the stage 23. FIG.

(Third step: Pressure plate temporary evacuation step)
The pressure plate temporary retracting step is performed as necessary.
Specifically, when the space between the functional film 13 formed on the first substrate 10 and the pressure plate 21 does not have a size that allows the second substrate 15 to be disposed, In other words, this is performed when the distance between the functional film 13 and the pressure plate 21 is smaller than the thickness of the second substrate 15. Therefore, the pressure plate temporary retracting step is omitted when the space between the functional film 13 and the pressure plate 21 has a size in which the second substrate 15 can be disposed.

In the pressurizing plate temporary retracting step, the pressurizing plate 21 is retracted by moving it upward as shown in FIG. In this way, the temporary retracting process of the pressure plate 21 is performed.
By passing through the pressure plate temporary retracting step, it is possible to secure a space for placing the second substrate 15 between the functional film 13 formed on the first substrate 10 and the pressure plate 21. Therefore, the second substrate 15 can be disposed on the first substrate 10.
In FIG.1 (c), the moving direction of the pressurization board 21 is shown by the arrow.

In the pressure plate temporary retracting process, the pressure plate 21 is merely moved upward, so that the positional relationship between the first substrate 10 and the pressure plate 21 adjusted in the pressure plate alignment adjusting process (specifically, the pressure plate 21 is adjusted). The state in which the protrusions 22B are aligned with the functional film 13) is maintained.

(4th process: stacking process)
In the stacking step, as shown in FIG. 1 (d), the surface of the functional film 13 formed on the first substrate 10 with the first substrate 10 and the second substrate 15 in a room temperature environment. And the bonding surface of the second substrate 15 are stacked in contact with each other. Here, the second substrate 15 is positioned by abutting the peripheral side surface of the second substrate 15 against all of the plurality of positioning pins 25 in the pressurizing mechanism, and is stacked on the first substrate 10. May be.
By passing through this stacking step, a stacked body is obtained in which the first substrate 10 and the second substrate 15 are bonded and bonded together in a state of being stacked via the functional film 13.
In this stacking step, the first substrate 10 and the second substrate 15 are bonded by various chemical reaction processes. For example, the bonding surface (functional film) of the first substrate 10 is used. 13 surface) and the terminal hydroxyl group of the bonding surface of the second substrate 15 are considered to be bonded by hydrogen bonding.

(Fifth step: Pressurization step)
In the pressurizing step, as shown in FIG. 1 (e), the stack obtained in the stacking step is subjected to pressurization using a pressurizing mechanism.
Specifically, by moving the pressure plate 21 positioned above the stacked body downward, the protrusion 22B of the pressure plate 21 is brought into contact with the second substrate 15 to press the stacked body, Pressurize. In this pressurizing process, the protrusion 22B and the functional film 13 are aligned through the pressure plate alignment adjustment step, so that the protrusion 22B is functional via the second substrate 15. The film 13 is opposed to the film 13.
In this way, in the pressurizing process, the stack obtained in the stacking process is selected for the contact portion between the functional film 13 formed on the first substrate 10 and the second substrate 15. The pressure is applied in the thickness direction so that an applied pressure is applied.
By passing through this pressurizing step, a joined body in which the first substrate 10 and the second substrate 15 are firmly joined is obtained.
In FIG.1 (e), the moving direction (pressurization direction) of the pressurization board 21 is shown by the arrow.

In order to firmly bond the first substrate 10 and the second substrate 15, it is preferable to perform a heating process together with a pressure process on the stacked body.

Specific methods for bonding the first substrate 10 and the second substrate 15 more firmly include the following methods (A) and (B).

(A) Method of heating while pressing the stack of the first substrate 10 and the second substrate 15 in the thickness direction (B) The stack of the first substrate 10 and the second substrate 15 in the thickness direction Method of heating after pressurizing and releasing pressure

Specific conditions in the pressing step are appropriately set according to the constituent material of the first substrate 10 and the constituent material of the second substrate 15.
Under the pressurizing condition, the applied pressure is equal to or higher than the pressure capable of correcting the minute deformation generated in the first substrate 10 and the second substrate 15 during the pressurizing step, and the first substrate 10 and the first substrate The pressure is less than the pressure at which the second substrate 15 is deformed. Specifically, for example, 0.2 to 10 MPa.
In the heating conditions when heating the first substrate 10 and the second substrate 15, the heating temperature is set to be lower than the temperature at which the first substrate 10 and the second substrate 15 are deformed.

(Sixth step: pressure plate retracting step)
In the pressure plate retracting step, the pressure plate 21 is retracted by moving it upward as shown in FIG. In this manner, the retracting process of the pressure plate 21 is performed.
By passing through the pressurizing plate retracting step, it is possible to take out the joined body formed by joining the first substrate 10 and the second substrate 15 via the functional film 13 from the pressurizing mechanism.
In FIG. 1 (f), the moving direction of the pressure plate 21 is indicated by an arrow.

Then, the joined body is taken out from the pressurizing mechanism in the bonding apparatus for two substrates of the present invention.

<Second Embodiment of First Bonding Method>
A second embodiment of the first bonding method (hereinafter also referred to as “first bonding method (2)”) is a surface activation process (1) in the first bonding method (1) described above. The first bonding method except that the first substrate surface activation step) is a plasma gas treatment step and that the second substrate plasma gas treatment step is provided instead of the second substrate ultraviolet irradiation treatment step. This is the same method as (1). That is, the first bonding method (2) is the same as the first bonding method except that in the first step, the bonding surface of the first substrate and the bonding surface of the second substrate are treated with plasma gas. This is the same method as (1).

In the first substrate surface activation step and the second substrate plasma gas treatment step of the first bonding method (2), the process gas plasmatized by atmospheric pressure plasma is applied to the bonding surface of the first substrate. (Specifically, the surface of the functional film) and the bonding surface of the second substrate are brought into contact with each other.

By passing through the first substrate surface activation step, the bonding surface of the first substrate, specifically, the surface of the functional film is modified so as to become a surface suitable for bonding. Is done. In addition, the bonded surface of the first substrate is cleaned by removing contaminants such as organic substances.

The second substrate plasma gas treatment process is not necessarily a necessary process, but is preferably performed from the viewpoint of bonding efficiency.
More specifically, the first substrate and the second substrate are bonded as long as the process gas is brought into contact with the bonding surface of the first substrate, that is, the surface of the functional film is activated. Can do. However, by passing through the second substrate plasma gas treatment step, contaminants such as organic substances are removed from the bonding surface of the second substrate, whereby the bonding surface is cleaned. By cleaning the bonding surface of the second substrate in this manner, the two substrates can be bonded efficiently.
In the second plasma gas processing step, depending on the constituent material of the second substrate, the bonding surface of the second substrate is activated to be a surface suitable for bonding. Quality.

In each of the first substrate surface activation step and the second substrate plasma gas processing step, an atmospheric pressure plasma apparatus is used as the plasma gas supply means.
FIG. 2 is a cross-sectional view illustrating the configuration of an example of an atmospheric pressure plasma apparatus used in the method for bonding two substrates of the present invention. This atmospheric pressure plasma apparatus has a rectangular parallelepiped casing 30 made of, for example, aluminum. A plate-like electrode 31 electrically connected to the high-frequency power source 35 is horizontally disposed in the casing 30. A dielectric layer 32 is formed on the lower surface of the electrode 31. In the atmospheric pressure plasma apparatus of this example, the electrode 31 is a high voltage side electrode and the casing 30 is a ground side electrode.
A gas supply port 33 for supplying process gas into the casing 30 is provided on the upper surface of the casing 30. In addition, a plurality of nozzles 34 are formed on the lower surface of the casing 30 to discharge process gas that has been plasmatized by atmospheric pressure plasma in the casing 30 to the outside.

In such an atmospheric pressure plasma apparatus, the process gas G1 is supplied from the gas supply port 33 into the casing 30 under atmospheric pressure or a pressure in the vicinity thereof. When a high frequency electric field is applied between the electrode 31 and the casing 30 via the dielectric layer 32 by the high frequency power source 35 in this state, a dielectric barrier discharge is generated between the electrode 31 and the casing 30. As a result, the process gas G1 existing between the casing 30 and the dielectric layer 32 is ionized or excited to be turned into plasma. Then, the plasma-processed process gas G2 is discharged to the outside from the nozzle 34 of the casing 30 and comes into contact with a bonding surface of a substrate (not shown) disposed below the casing 30.
In the above, it is preferable to use the process gas G1 containing nitrogen gas, argon gas or the like as a main component and containing 0.01 to 5% by volume of oxygen gas. Alternatively, a mixed gas of nitrogen gas and clean dry air (CDA) can be used.
The power supplied from the high frequency power supply 35 has a frequency of 20 to 70 kHz and a voltage of 5 to 15 kVp-p.
Further, the processing time by the plasma gas processing is, for example, 5 to 100 seconds.

In such a first bonding method (specifically, the first bonding method (1) and the first bonding method (2)), the first substrate 10 is shaped in the pressing step. A pressurizing force selectively acts on the contact portion between the provided functional film 13 and the second substrate 15. Therefore, even if the first substrate 10 has a larger deformability than the second substrate 15, the first substrate 10 is bonded to the bonding surface of the first substrate 10 in the peripheral region of the functional film 13. It is prevented or sufficiently suppressed that the substrate 10 and the second substrate 15 are deformed such that the substrate 10 and the second substrate 15 are in direct contact without interposing the functional film 13.
Therefore, according to the first bonding method, the first substrate 10 and the second substrate 15 are bonded via the functional film 13 so as not to be in direct contact without passing through the functional film 13. be able to. That is, it is possible to avoid production of a bonded body in a state where the first substrate 10 and the second substrate 15 are in direct contact with each other in the peripheral region of the functional film 13.

Thus, by producing the light emitting surface forming member of the surface emitting light source unit by the first bonding method, for example, the second substrate 15 is the light guide plate, the functional film 13 is the diffusion member layer, the first When the substrate 10 is a reflector, a part of the light guide plate (second substrate 15) and a part of the reflector (first substrate 10) are not diffused through the diffusion member layer (functional film 13). Direct contact in the peripheral region of the member layer is avoided. Therefore, in the light emitting surface forming member obtained, stray light generated due to the presence of a region where the light guide plate (second substrate 15) and the reflection plate (first substrate 10) are in direct contact with each other does not cause the light guide plate ( Since it is prevented from being superimposed on the light emitted from the upper surface of the second substrate 15), light having a predetermined intensity distribution can be extracted from the upper surface of the light guide plate (second substrate 15).

In the first bonding method, in the pressurizing step, the first substrate 10 and the second substrate 15 having a low deformability, specifically, the second substrate 15 is a pressure plate. Therefore, neither the first substrate 10 nor the second substrate 15 is deformed. Therefore, in the obtained bonded body, occurrence of peeling between the first substrate 10 and the second substrate 15 due to the residual stress is suppressed.
Specifically, as shown in FIG. 3, when the first substrate 10 having a large deformability is brought into contact with the pressure plate 21, the first substrate 10 is bonded to the first substrate 10. Although the mating surfaces are not deformed, deformation (specifically, a dent corresponding to the shape of the protrusion 22B) may occur on the surface with which the pressure plate 21 is in contact, which may cause residual stress. And when residual stress generate | occur | produces, in the obtained bonded body, there exists a possibility that peeling may arise between the 1st board | substrate 10 and the 2nd board | substrate 15 resulting from the residual stress. However, when the second substrate 15 having a small deformability is brought into contact with the pressure plate 21, even when a pressure is locally applied to the stack by the pressure plate 21, it is caused by that. Thus, deformation of the stacked body can be prevented or sufficiently suppressed.

In the first bonding method, vacuum ultraviolet rays are irradiated to the bonding surface of the second substrate 15 in the second substrate ultraviolet irradiation process or the second substrate plasma gas processing process in the first process. In addition, the contact surface of the second substrate 15 is cleaned by contacting the process gas that has been converted into plasma by atmospheric pressure plasma, so that the two substrates can be bonded efficiently. .

Further, in the first bonding method, since the bonding apparatus for two substrates of the present invention is used in the pressurizing step, by an easy method of pressing the stack with the pressure plate 21, The first substrate 10 and the second substrate 15 can be bonded together via the functional film 13.

[Second bonding method]
Hereinafter, two embodiments of the second bonding method according to the method for bonding two substrates of the present invention will be described.

<First Embodiment of Second Bonding Method>
A first embodiment of the second bonding method (hereinafter also referred to as “second bonding method (1)”) will be described in detail with reference to FIG.
In the second bonding method (1), the first substrate 10 is less deformable than the second substrate 15, and specifically, for example, the first substrate 10 is It is made of COP, acrylic resin or glass, and the second substrate 15 is made of PET resin. The functional film 13 is made of PDMS. And the joined body obtained is a constituent member of a surface-emitting light source unit used as a backlight of a display, specifically, a light guide plate made of COP, acrylic resin or glass, a diffusion member layer made of PDMS, and PET A reflecting plate made of a resin is used as a light emitting surface forming member formed by laminating in this order. In this bonded body, the functional film 13 has an optical function as well as a function contributing to bonding.

In the second bonding method (1), the surface of the second substrate 15 subjected to the stacking step as shown in FIG. 4 (a-2) is obtained through the steps (1) to (3). An ultraviolet irradiation treatment is performed on the (bonding surface). In addition, as shown in FIG. 4 (e), the second bonding method (1) is performed by using the two substrate bonding apparatus of the present invention in the pressurizing step. -1), (b-2), (d), and (f), the second substrate 15 alignment adjustment processing, the pressure plate 21 alignment adjustment processing, and the pressure plate 21 retraction processing are performed. .

In the bonding apparatus for two substrates of the present invention used in the second bonding method (1), the pressurizing mechanism is the first as shown in FIGS. 4 (d) to (f). It has the same structure as the pressure mechanism of the bonding apparatus for two substrates of the present invention used in the bonding method.
That is, in the two-substrate bonding apparatus of the present invention used in the second bonding method (1), the pressurizing mechanism includes a rectangular plate-like stage 23 for placing the substrate, and the first A pressure plate 21 having a protrusion 22B having a shape corresponding to the functional film 13 formed on the substrate 10 is provided. The stage 23 has a flat substrate placement surface 23A, and a plurality of (3 in the example of FIG. 4) extend perpendicularly from the substrate placement surface 23A at the peripheral portion of the substrate placement surface 23A. Book) positioning pins 25 are provided. The positioning pins 25 are alignment adjusting means having a positioning function with respect to the substrate and the pressure plate 21. In other words, the positioning pin 25 constitutes an alignment adjusting means for the stacked body (specifically, the stacked body of the first substrate 10 and the second substrate 15) and the pressure plate 21. The pressure plate 21 has a protrusion 22B on the surface (the lower surface in FIGS. 4D, 4E, and 4F) of a rectangular plate-shaped substrate 22A. The pressure plate 21 has the surface of the pressure plate 21 facing the substrate placement surface 23A and is positioned by the positioning pins 25, so that the protrusion 22B is placed on the substrate placement surface 23A. The functional film 13 formed on the first substrate 10 is opposed to the functional film 13. The pressure plate 21 is provided to be movable in the vertical direction on the substrate placement surface 23A.
In the example shown in the figure, the pressure plate 21 has a base material 22A having the same vertical and horizontal dimensions as the first substrate 10 and the second substrate 15, and a protrusion height of 1 mm at the center of the base material 22A. The protrusion 22B is provided.

In the second bonding method (1), first, a rectangular flat plate-like first substrate 10 and a rectangular flat plate-like second substrate having a surface having a size suitable for the surface of the first substrate 10. 15 are prepared. Then, a functional film 13 having an outer shape defined by screen printing or the like is formed on the surface of the first substrate 10. In the first substrate 10, the surface on which the functional film 13 is formed serves as a bonding surface with the second substrate 15. On the other hand, in the second substrate 15, the surface having a size suitable for the bonding surface of the first substrate 10 is the bonding surface with the first substrate 10.
In the example of this figure, a functional film 13 having a defined outer shape (specifically, a rectangular outer shape) and a thickness of 10 μm is formed on the first substrate 10 at the center of the bonding surface. ing.

(First step: first substrate surface activation step and second substrate ultraviolet irradiation treatment step)
In the first substrate surface activation process and the second substrate ultraviolet irradiation process, as shown in FIGS. 4A-1 and 4A-2, the bonding surface of the first substrate 10 ( 4A-1 and the bonding surface of the second substrate 15 (upper surface in FIG. 4A-2) are vacuum ultraviolet rays (ultraviolet rays having a wavelength of 200 nm or less) L1, L2 in an air atmosphere. Irradiate.

Through the first substrate surface activation step, the bonding surface of the first substrate 10, specifically, the surface of the functional film 13 (upper surface in FIG. 4A-1) is activated. And modified so that the surface is suitable for bonding. Specifically, the surface of the functional film 13 is hydrophilized in a state where, for example, a hydroxy group (OH group) exists. That is, the surface of the functional film 13 is terminated with a hydroxy group by introducing a hydroxy group derived from moisture in the atmosphere. In addition, the bonding surface of the first substrate 10 is cleaned by removing contaminants such as organic substances.

(Second step: second substrate alignment adjustment step)
In the second substrate alignment adjustment step, as shown in FIGS. 4B-1 and 4B-2, the second substrate 15 is placed on the substrate placement surface 23A of the stage 23, and An alignment adjustment process (positioning adjustment process) of the second substrate 15 is performed.
Specifically, with the second substrate 15 in a state where the back surface (the lower surface in FIG. 4B-1) is in contact with the substrate placement surface 23A of the stage 23, the peripheral side surface is all of the plurality of positioning pins 25. The substrate is positioned by abutting and placed at a predetermined position on the substrate placement surface 23A. In this way, the alignment adjustment process for the second substrate 15 is performed.
4B-1 is an explanatory side view showing a state where the second substrate 15 is placed on the placement surface 23A of the stage 23. FIG. FIG. 4B-2 is an explanatory diagram showing the mounting state of the second substrate 15 on the substrate mounting surface 23A of the stage 23. FIG.

(Third process: stacking process)
In the stacking step, as shown in FIG. 4C, the surface of the functional film 13 formed on the first substrate 10 with the first substrate 10 and the second substrate 15 in a room temperature environment. And the bonding surface of the second substrate 15 are stacked in contact with each other. Here, the first substrate 10 is positioned by abutting the peripheral side surface of the first substrate 10 against all of the plurality of positioning pins 25 in the pressurizing mechanism, and is stacked on the second substrate 15. May be.
By passing through this stacking step, a stacked body is obtained in which the first substrate 10 and the second substrate 15 are bonded and bonded together in a state of being stacked via the functional film 13.
In this stacking step, the first substrate 10 and the second substrate 15 are bonded by various chemical reaction processes. For example, the bonding surface (functional film) of the first substrate 10 is used. 13 surface) and the terminal hydroxyl group of the bonding surface of the second substrate 15 are considered to be bonded by hydrogen bonding.

(4th process: pressure plate alignment adjustment process)
In the pressure plate alignment adjustment step, as shown in FIG. 4D, the alignment adjustment process of the pressure plate 21 is performed in a state where the stacked body is placed on the substrate placement surface 23 </ b> A of the stage 23.
Specifically, the peripheral surface of the base material 22A is positioned in a plurality of positions in a state in which the pressure plate 21 faces the stacking body placed on the substrate placement surface 23A with the surface having the protrusion 22B slightly spaced from the stacked body. Positioning is done by hitting all of the pins 25. In this way, the alignment adjustment process of the pressure plate 21 is performed. Thus, the protruding portion 22B of the pressure plate 21 is aligned so as to face the functional film 13 through the first substrate 10 and the space.

(Fifth step: Pressurization step)
In the pressurizing step, as shown in FIG. 4E, the stack obtained in the stacking step is subjected to a pressurizing process using a pressurizing mechanism.
Specifically, by moving the pressure plate 21 positioned above the stack to move downward, the protrusion 22B of the pressure plate 21 is brought into contact with the first substrate 10 to press the stack. Pressurize. In this pressurizing process, the protrusion 22B and the functional film 13 are aligned by passing through the pressure plate alignment adjustment step, so that the protrusion 22B is functional via the first substrate 10. The film 13 is opposed to the film 13.
In this way, in the pressurizing process, the stack obtained in the stacking process is selected for the contact portion between the functional film 13 formed on the first substrate 10 and the second substrate 15. The pressure is applied in the thickness direction so that an applied pressure is applied.
By passing through this pressurizing step, a joined body in which the first substrate 10 and the second substrate 15 are firmly joined is obtained.
In FIG.4 (e), the moving direction (pressurization direction) of the pressurization board 21 is shown by the arrow.

Specific methods for bonding the first substrate 10 and the second substrate 15 more firmly include the methods (A) and (B) described above.

(Sixth step: pressure plate retracting step)
In the pressure plate retracting step, as shown in FIG. 4F, the pressure plate 21 is retracted by moving upward. In this manner, the retracting process of the pressure plate 21 is performed.
By passing through the pressurizing plate retracting step, it is possible to take out the joined body formed by joining the first substrate 10 and the second substrate 15 via the functional film 13 from the pressurizing mechanism.
In FIG. 4F, the moving direction of the pressure plate 21 is indicated by an arrow.

<Second Embodiment of Second Bonding Method>
A second embodiment of the second bonding method (hereinafter also referred to as “second bonding method (2)”) is a surface activation step (in the second bonding method (1) described above). The second bonding method except that the first substrate surface activation step) is a plasma gas treatment step and that the second substrate plasma gas treatment step is provided instead of the second substrate ultraviolet irradiation treatment step. This is the same method as (1). That is, in the second bonding method (2), in the first step, the second bonding is performed except that the bonding surface of the first substrate and the bonding surface of the second substrate are treated with plasma gas. This is the same method as method (1).

In the first substrate surface activation step and the second substrate plasma gas treatment step of the second bonding method (2), the process gas plasmatized by atmospheric pressure plasma is used as the bonding surface of the first substrate. (Specifically, the surface of the functional film) and the bonding surface of the second substrate are brought into contact with each other.

In the first substrate surface activation step and the second substrate plasma gas processing step, an atmospheric pressure plasma apparatus is used as the plasma gas supply means.

In such a second bonding method (specifically, the second bonding method (1) and the second bonding method (2)), the first substrate 10 is shaped in the pressing step. A pressurizing force selectively acts on the contact portion between the provided functional film 13 and the second substrate 15. Therefore, even if the second substrate 15 has a larger deformability than the first substrate 10, the first substrate 15 is bonded to the bonding surface of the second substrate 15 in the peripheral region of the functional film 13. It is prevented or sufficiently suppressed that the substrate 10 and the second substrate 15 are deformed such that the substrate 10 and the second substrate 15 are in direct contact without interposing the functional film 13.
Therefore, according to the second bonding method, the first substrate 10 and the second substrate 15 are bonded via the functional film 13 so as not to be in direct contact without the functional film 13 being interposed. be able to. That is, it is possible to avoid production of a bonded body in a state where the first substrate 10 and the second substrate 15 are in direct contact with each other in the peripheral region of the functional film 13.

Thus, by producing the light emitting surface forming member of the surface emitting light source unit by the second bonding method, for example, the first substrate 10 is the light guide plate, the functional film 13 is the diffusion member layer, the second When the substrate 15 is a reflector, a part of the light guide plate (first substrate 10) and a part of the reflector (second substrate 15) are not diffused through the diffusion member layer (functional film 13). Direct contact in the peripheral region of the member layer is avoided. Therefore, in the light emitting surface forming member to be obtained, stray light generated due to the presence of a region where the light guide plate (first substrate 10) and the reflection plate (second substrate 15) are in direct contact with each other does not cause the light guide plate ( Since it is prevented from being superimposed on the light emitted from the upper surface of the first substrate 10), light having a predetermined intensity distribution can be extracted from the upper surface of the light guide plate (first substrate 10).

In the second bonding method, in the pressurizing step, the first substrate 10 and the second substrate 15 having a low deformability, specifically, the first substrate 10 is a press plate. Therefore, neither the first substrate 10 nor the second substrate 15 is deformed. Therefore, in the obtained bonded body, occurrence of peeling between the first substrate 10 and the second substrate 15 due to the residual stress is suppressed.

In the second bonding method, vacuum ultraviolet rays are irradiated on the bonding surface of the second substrate 15 in the second substrate ultraviolet irradiation process or the second substrate plasma gas processing process of the first process. In addition, the contact surface of the second substrate 15 is cleaned by contacting the process gas that has been converted into plasma by atmospheric pressure plasma, so that the two substrates can be bonded efficiently. .

Further, in the second bonding method, since the two substrate bonding apparatus of the present invention is used in the pressing step, an easy method of pressing the stack against the pressure plate 21. Thus, the first substrate 10 and the second substrate 15 can be bonded together via the functional film 13.

The method for bonding two substrates of the present invention is not limited to the above embodiment, and various modifications can be made.
For example, a plurality of functional films may be formed on the surface of the first substrate.
In addition, the pressure plate is not limited to the one in which the protrusions are integrally formed on the base material as shown in FIGS. 1 and 4, and the flat base material and the protrusions that are separate from the base material A combination with a forming member can also be used. Specifically, for example, a combination of a rectangular flat plate-like base material and a shim (SIM) having a shape corresponding to the functional film formed on the surface of the first substrate may be used. In the pressure plate having such a configuration, in order to arrange the protrusion forming member at a position corresponding to the functional film formed on the surface of the first substrate, the protrusion forming member is aligned and adjusted. That is, it is necessary to adjust the arrangement position.
Further, in the apparatus for laminating two substrates of the present invention, the alignment adjusting means for the pressure plate and the stacked body is not limited to one constituted by positioning pins as shown in FIGS. That is, the pressurizing mechanism is not limited to the one that performs alignment adjustment processing of the substrate and the pressure plate by the positioning pins as shown in FIGS. 1 and 4, and the alignment adjustment processing of the substrate and the pressure plate is performed by other alignment adjusting means. You may do it. Specifically, for example, a known image processing unit may be used as the alignment adjustment unit. In the pressurization mechanism having such a configuration, when the first substrate is made of a transparent material, the first substrate is placed on the substrate placement surface of the stage, and then the first processing is performed by the image processing means. While detecting the position of the functional film on the surface of the substrate, the functional film is detected by detecting the image information of the alignment mark provided in the pressure mechanism corresponding to the position of the protrusion of the pressure plate. And the alignment adjustment process between the protrusions. On the other hand, when the first substrate is not made of a transparent material, the back surface of the first substrate (the surface opposite to the surface on which the functional film is formed) is aligned with the position of the functional film. By providing the mark and detecting image information of the alignment mark of the first substrate and the alignment mark provided in the pressurizing mechanism, the alignment adjustment process between the functional film and the protrusion is performed.

Hereinafter, experimental examples of the present invention will be described.

[Experimental Example 1]
A rectangular flat plate substrate (sheet) made of PET resin having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 0.2 mm is prepared as the first substrate, and a PMMA having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 2 mm is prepared as the second substrate. A rectangular flat substrate made of (polymethyl methacrylate) resin was prepared. The second substrate has a constituent material that is harder than the first substrate and has a large thickness. Therefore, the second substrate is less deformable than the first substrate.
Then, after forming a functional film made of PDMS having a vertical and horizontal dimension of 10 mm × 10 mm and a thickness of 10 μm on the surface of the first substrate by screen printing, the bonding apparatus for two substrates of the present invention shown in FIG. Was used to produce a joined body of the first substrate and the second substrate by the first bonding method (1).
Specifically, first, the bonding surface of the first substrate and the bonding surface of the second substrate were each irradiated with a vacuum ultraviolet ray from a xenon excimer lamp in an air atmosphere (first substrate surface activation). Process and second substrate ultraviolet irradiation process). The irradiation conditions of the vacuum ultraviolet rays were a bonding surface illuminance (irradiance) of 50 mW / cm ² and an irradiation time of 100 seconds.
Next, after the first substrate is placed on the substrate placement surface of the stage of the pressure mechanism with the bonding surface facing upward and the peripheral side surface being abutted against all the alignment pins, the pressure is applied. The pressure plate alignment adjustment process of the mechanism was performed (pressure plate alignment adjustment step).
Then, a space for placing the second substrate is secured by moving the pressure plate upward (pressure plate temporary retracting step), and then the surface of the functional film formed on the first substrate and the first substrate 2 is brought into contact with the bonding surface of the two substrates to obtain a stacked body (stacking step), and the obtained stacked body is pressed in the thickness direction of the stacked body by moving the pressure plate downward (acceleration). Pressure process). The pressurizing conditions were a pressure of 5 MPa and a pressurization time of 5 seconds.
Thereafter, the pressure plate was moved upward (pressure plate retracting step), and the joined body (hereinafter, also referred to as “joined body (1-1)”) was taken out from the pressure mechanism.
When the obtained bonded body (1-1) was visually observed, as shown in FIG. 5 (a), the functional film formed on the first substrate and the second substrate were bonded together. As a result, the first substrate and the second substrate are not in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is not formed.
In FIG. 5A, the bonding region and the functional film arrangement region are indicated by hatching.

Also, as the pressure plate constituting the pressure mechanism, a projection plate is not provided and the surface facing the substrate mounting surface of the stage is flat, specifically, a rectangular flat plate is used. Then, a bonded body (hereinafter also referred to as “bonded body (1-2)”) was obtained by the same method as in the first bonding method (1).
When the obtained bonded body (1-2) was visually observed, as shown in FIG. 5B, the functional film formed on the first substrate and the second substrate were bonded together. In addition, the first substrate and the second substrate are in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is formed.
In FIG. 5 (b), the bonding area is indicated by hatching, and the arrangement position of the functional film located in the bonding area is indicated by a solid square.

[Experiment 2]
A rectangular flat plate substrate made of alkali-free glass having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 1 mm is prepared as a first substrate, and a rectangle made of PET resin having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 0.2 mm is prepared as a second substrate. A flat substrate (sheet) was prepared. The first substrate has a harder constituent material and a larger thickness than the second substrate, and thus has a smaller deformability than the second substrate.
Then, after a functional film made of PET having a vertical and horizontal dimension of 10 mm × 10 mm and a thickness of 10 μm is formed on the surface of the first substrate by screen printing, the bonding apparatus for two substrates of the present invention shown in FIG. Was used to produce a joined body of the first substrate and the second substrate by the second bonding method (1).
Specifically, first, the bonding surface of the first substrate and the bonding surface of the second substrate were each irradiated with a vacuum ultraviolet ray from a xenon excimer lamp in an air atmosphere (first substrate surface activation). Process and second substrate ultraviolet irradiation process). The irradiation conditions of the vacuum ultraviolet rays were a bonding surface illuminance (irradiance) of 50 mW / cm ² and an irradiation time of 100 seconds.
Next, the second substrate was placed on the substrate placement surface of the stage of the pressurizing mechanism with the bonding surface facing upward and the peripheral side surface being abutted against all of the alignment pins (second substrate). Alignment adjustment process).
Then, the surface of the functional film formed on the first substrate is brought into contact with the bonding surface of the second substrate to obtain a stack (stacking step), and then the alignment of the pressure plate of the pressure mechanism An adjustment process was performed (pressure plate alignment adjustment step), and the obtained pressure plate was moved in the thickness direction by moving the pressure plate downward (pressure step). The pressurizing conditions were a pressure of 5 MPa and a pressurization time of 5 seconds.
Thereafter, the pressure plate was moved upward (pressure plate retracting step), and the joined body (hereinafter also referred to as “joined body (2-1)”) was taken out from the pressurizing mechanism.
When the obtained bonded body (2-1) was visually observed, as shown in FIG. 5A, the functional film formed on the first substrate and the second substrate were bonded together. As a result, the first substrate and the second substrate are not in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is not formed.

Also, as the pressure plate constituting the pressure mechanism, a projection plate is not provided and the surface facing the substrate mounting surface of the stage is flat, specifically, a rectangular flat plate is used. Then, a joined body (hereinafter also referred to as “joined body (2-2)”) was obtained in the same manner as in the second bonding method (1).
When the obtained bonded body (2-2) was visually observed, as shown in FIG. 5B, the functional film formed on the first substrate and the second substrate were bonded together. In addition, the first substrate and the second substrate are in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is formed.

[Experimental Example 3]
A rectangular flat substrate (sheet) made of PET resin having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 0.2 mm is prepared as the first substrate, and a PET having a vertical and horizontal dimension of 100 mm × 100 mm and a thickness of 2 mm is prepared as the second substrate. A resin-made rectangular flat substrate was prepared. The second substrate is thicker than the first substrate, and thus has less deformability than the first substrate.
Then, after forming a functional film made of PDMS having a vertical and horizontal dimension of 10 mm × 10 mm and a thickness of 10 μm on the surface of the first substrate by screen printing, the bonding apparatus for two substrates of the present invention shown in FIG. Was used to produce a joined body of the first substrate and the second substrate by the first bonding method (2).
Specifically, first, plasma gas treatment was performed on the bonding surface of the first substrate and the bonding surface of the second substrate using the atmospheric pressure plasma apparatus shown in FIG. Substrate surface activation step and second substrate plasma processing step). The atmospheric pressure plasma apparatus used here is a super invar in which the casing material is aluminum, and the electrode material is formed on the surface with a coating made of alumina having a thickness of 500 μm, and the electrode dimensions are 50 mm × 300 mm, the distance between the casing and the dielectric layer is 0.5 mm, the voltage is 7.0 kVp-p, the frequency is 60 kHz, and the rated power is 1100 VA.
That is, each of the first substrate and the second substrate was disposed at a position 3 mm away from the nozzle below the atmospheric pressure plasma apparatus so that the bonding surface thereof faces the nozzle. Then, while supplying nitrogen gas having a flow rate of 150 L / min and clean dry air having a flow rate of 1 L / min (the oxygen concentration in the process gas is about 0.14 vol%) as the process gas into the casing, the atmospheric pressure plasma apparatus The plasma gas treatment for 5 seconds was performed on each of the bonding surface of the first substrate and the bonding surface of the second substrate.
Next, after the first substrate is placed on the substrate placement surface of the stage of the pressure mechanism with the bonding surface facing upward and the peripheral side surface being abutted against all the alignment pins, the pressure is applied. The pressure plate alignment adjustment process of the mechanism was performed (pressure plate alignment adjustment step).
Then, a space for placing the second substrate is secured by moving the pressure plate upward (pressure plate temporary retracting step), and then the surface of the functional film formed on the first substrate and the first substrate 2 is brought into contact with the bonding surface of the two substrates to obtain a stacked body (stacking step), and the obtained stacked body is pressed in the thickness direction of the stacked body by moving the pressure plate downward (acceleration). Pressure process). The pressurizing conditions were a pressure of 5 MPa and a pressurization time of 5 seconds.
Thereafter, the pressure plate was moved upward (pressure plate retracting step), and the joined body (hereinafter also referred to as “joined body (1-3)”) was taken out from the pressure mechanism.
When the obtained bonded body (1-3) was visually observed, as shown in FIG. 5A, the functional film formed on the first substrate and the second substrate were bonded together. As a result, the first substrate and the second substrate are not in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is not formed.

Also, as the pressure plate constituting the pressure mechanism, a projection plate is not provided and the surface facing the substrate mounting surface of the stage is flat, specifically, a rectangular flat plate is used. Then, a bonded body (hereinafter also referred to as “bonded body (1-4)”) was obtained by the same method as in the first bonding method (2).
When the obtained bonded body (1-4) was visually observed, as shown in FIG. 5B, the functional film formed on the first substrate and the second substrate were bonded together. In addition, the first substrate and the second substrate are in direct contact with each other in the peripheral region of the functional film, and an undesired direct contact region is formed.

Results of Experimental Example 1, Experimental Example 2 and Experimental Example 3 are shown in Tables 1 and 2 below.

From the results of Experimental Example 1, Experimental Example 2, and Experimental Example 3 described above, according to the method for bonding two substrates of the present invention, the first It was confirmed that the substrate and the second substrate can be bonded together via a functional film.

DESCRIPTION OF SYMBOLS 10 1st board | substrate 13 Functional film | membrane 15 2nd board | substrate 21 Pressure plate 22A Base material 22B Protrusion part 23 Stage 23A Substrate mounting surface 25 Positioning pin 30 Casing 31 Electrode 32 Dielectric layer 33 Gas supply port 34 Nozzle 35 High frequency power supply 40 First substrate 43 Bonding film 45 Second substrate 49 Direct contact area 51 Light source 61 Light guide plate 61a, 61b Side surface 63 Reflector plate 66 Diffusing member layer 71 Pressure plate 73 Stage 73A Substrate mounting surface L1, L2 Vacuum ultraviolet ray L3 L4 UV

Claims

A method of bonding two substrates, in which a first substrate and a second substrate having a functional film having a defined outer shape formed on the surface are bonded via the functional film,
A surface activation step for activating the surface of the functional film formed on the surface of the first substrate;
Stacking the first substrate and the second substrate that have passed through the surface activation step so that the surface of the functional film and the bonding surface of the second substrate are in contact with each other. And a stack of the first substrate and the second substrate obtained in the stacking step is selectively applied to a contact portion between the functional film and the second substrate. A method for bonding two substrates, including a pressing step of pressing in the thickness direction.
The pressurizing step uses a pressure plate having a protrusion having a shape corresponding to the functional film formed on the surface of the first substrate, and the protrusion is the first substrate or the second substrate. 2. The method for bonding two substrates according to claim 1, wherein the method is performed by pressing the pressure plate in a state of being positioned so as to face the functional film via the substrate.
The bonding of two substrates according to claim 2, wherein a substrate having a small deformability among the first substrate and the second substrate is in contact with the pressure plate. Method.
4. A process gas that is subjected to the stacking step and is irradiated with vacuum ultraviolet rays or brought into plasma by atmospheric plasma is brought into contact with the bonding surface of the second substrate. A method for bonding two substrates according to any one of the above.
The surface activation step is an ultraviolet ray irradiation treatment step of irradiating the surface of the functional film formed on the surface of the first substrate with vacuum ultraviolet rays. A method for bonding two substrates according to any one of the above.
The surface activation step is a plasma gas treatment step in which a process gas converted into plasma by atmospheric pressure plasma is brought into contact with the surface of a functional film formed on the surface of the first substrate. The method for bonding two substrates according to any one of claims 1 to 3.
An apparatus for laminating two substrates for laminating a first substrate and a second substrate having a functional film having a defined outer shape formed on the surface via the functional film. ,
A pressurizing mechanism is provided for pressurizing the stack in a thickness direction in a state where the surface of the functional film of the first substrate and the bonding surface of the second substrate are in contact with each other;
A pressure plate having a protrusion having a shape corresponding to the functional film formed on the surface of the first substrate; and an alignment adjusting unit between the pressure plate and the stack. An apparatus for laminating two substrates, wherein a pressing force is selectively applied to a contact portion between the functional film and the second substrate.