Manufacturing methods for electronic devices

Abstract

To suppress the generation of an out gas, and suppress deterioration of an optical characteristic of a cover glass.SOLUTION: A manufacturing method of an electronic device, contains: a baking step of heating a cover glass in which a reflection prevention layer formed by a hardening material of an unhardened optical hardening resin containing of a photopolymerization component; an assemble step of assembling a sensor module by installing the cover glass after the baking step to a position opposite to a light reception surface of a sensor element; and a reflow step of mounting the sensor module onto a mounting substrate, and heating the sensor module by a temperature of 250°C or more to perform it the mounting substrate with a solder. By performing the baking step before the reflow step, the generation ratio of the out gas derived from the photopolymerization component from the out gas generated from the reflection prevention layer of the cover glass in the reflow step is 0.3 mass% or less against a mass of the reflection prevention layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an electronic device and a cover glass. [Background technology]

[0002] An electronic device having a sensor element mounted on a mounting substrate is provided in, for example, a mobile terminal such as a smartphone, an automobile, a monitoring system, etc. In the electronic device, in order to improve the sensitivity of the sensor element, the sensor element is covered with a cover glass having an anti-reflection function.

[0003] As a cover glass having an anti-reflection function, a cover glass having an anti-reflection layer made of a resin having a fine uneven structure has been developed. Such a cover glass is manufactured by supplying a curable resin composition between a master and a substrate, curing the composition, and transferring the fine uneven structure of the master to the surface of the curable resin composition (nanoimprint method) (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-214101 A Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing the electronic device, a cover glass is first placed in a position facing the light receiving surface of the sensor element to assemble the sensor module. The sensor module is then placed on a mounting board and heated to solder (reflow) the sensor module to the mounting board.

[0006] In this way, the sensor module is heated during reflow, which causes outgassing from the anti-reflection layer of the cover glass. The outgassing deteriorates the optical properties of the cover glass, in particular reducing the transmittance of light with wavelengths of 400 nm or more.

[0007] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a method for manufacturing an electronic device and a cover glass that can suppress the generation of outgassing and suppress deterioration of the optical properties of the cover glass. [Means for solving the problem]

[0008] In order to solve the above problems, according to one aspect of the present invention, A method for manufacturing an electronic device in which a sensor element covered with a cover glass is mounted on a mounting substrate, comprising the steps of: The cover glass is A glass substrate; an antireflection layer provided on at least one surface of the glass substrate, the antireflection layer having a fine uneven structure in which the average period of unevenness is equal to or shorter than the wavelength of visible light; Equipped with The manufacturing method includes: (1) a transfer step of transferring the fine relief structure of a master to an uncured resin layer made of an uncured photocurable resin provided on at least one surface of the glass substrate; (2) a curing step of irradiating the uncured resin layer to which the fine unevenness structure has been transferred with light to cure the uncured resin layer, thereby forming the antireflection layer made of a cured product of the photocurable resin; (3) a baking step of heating the cover glass on which the anti-reflection layer is formed; (4) an assembly process of assembling a sensor module by placing the cover glass after the baking process at a position facing a light receiving surface of the sensor element; (5) a reflow process in which the sensor module is placed on the mounting board and heated at a temperature of 250° C. or higher to solder the sensor module to the mounting board; Including, The uncured photocurable resin is Contains a photopolymerizable component, The photopolymerizable component includes a resin (A) and a resin (B), The resin (A) is a monofunctional acrylate monomer having a phenyl group, The resin (B) is a di- or higher functional acrylate monomer, The content of the resin (A) relative to the total amount of the photopolymerizable components is more than 10% by mass and not more than 40% by mass, The content of the resin (B) relative to the total amount of the photopolymerizable components is 60% by mass or more and less than 90% by mass, By carrying out the baking step prior to the reflow step, a generation rate of outgassing originating from the photopolymerizable component among outgassing generated from the antireflection layer of the cover glass in the reflow step is 0.3 mass% or less relative to the mass of the antireflection layer, thereby providing a method for manufacturing an electronic device.

[0009] In the reflow step, the rate of outgassing generated from the antireflection layer of the cover glass and originating from the resin (A) may be less than 0.2% by mass.

[0010] The resin (B) may be a monomer having a cyclic structure in the molecule.

[0011] In the baking step, the cover glass on which the antireflection layer is formed may be heated at a temperature of 150° C. or higher and lower than 250° C. for 10 minutes or longer.

[0012] The anti-reflection layer is provided on both surfaces of the glass substrate, In the transferring step, the fine relief structure of the master may be transferred to the uncured resin layers provided on both surfaces of the glass substrate.

[0013] The sensor element may be an image sensor.

[0014] In order to solve the above problems, according to another aspect of the present invention, A method for manufacturing an electronic device in which a sensor element covered with a cover glass is mounted on a mounting substrate, comprising the steps of: The cover glass is A glass substrate; an antireflection layer provided on at least one surface of the glass substrate, the antireflection layer having a fine uneven structure in which the average period of unevenness is equal to or shorter than the wavelength of visible light; Equipped with The manufacturing method includes: (1) a transfer step of transferring the fine relief structure of a master to an uncured resin layer made of an uncured photocurable resin provided on at least one surface of the glass substrate; (2) a curing step of irradiating the uncured resin layer to which the fine unevenness structure has been transferred with light to cure the uncured resin layer, thereby forming the antireflection layer made of a cured product of the photocurable resin; (3) a baking step of heating the cover glass on which the anti-reflection layer is formed; (4) an assembly process of assembling a sensor module by placing the cover glass after the baking process at a position facing a light receiving surface of the sensor element; (5) a reflow process in which the sensor module is placed on the mounting board and heated at a temperature of 250° C. or higher to solder the sensor module to the mounting board; Including, The uncured photocurable resin is Contains a photopolymerizable component, The photopolymerizable component includes a resin (A) and a resin (B), The resin (A) is a monofunctional acrylate monomer having a phenyl group, The resin (B) is a di- or higher functional acrylate monomer, The content of the resin (A) relative to the total amount of the photopolymerizable components is more than 10% by mass and not more than 40% by mass, The content of the resin (B) relative to the total amount of the photopolymerizable components is 60% by mass or more and less than 90% by mass, There is provided a method for producing an electronic device, wherein in the baking step, the cover glass on which the antireflection layer is formed is heated at a temperature of 150° C. or higher and lower than 250° C. for 10 minutes or longer.

[0015] The baking step may be performed prior to the reflow step so that, in the reflow step, the rate of outgassing generated from the antireflection layer of the cover glass and originating from the photopolymerization component is 0.3 mass % or less relative to the mass of the antireflection layer.

[0016] In order to solve the above problems, according to another aspect of the present invention, A cover glass for covering a sensor element mounted on a mounting substrate of an electronic device, A glass substrate; an anti-reflection layer provided on at least one surface of the glass substrate, having a fine uneven structure in which the average period of unevenness is equal to or shorter than the wavelength of visible light, and made of a cured product of a photocurable resin; Equipped with the cured product of the photocurable resin is a polymer of resin (A) and resin (B), The resin (A) is a monofunctional acrylate monomer having a phenyl group, The resin (B) is a di- or higher functional acrylate monomer, The cover glass is provided, in which the content of residual monomers derived from the resin (A) contained in the polymer is 0.25 mass % or less. Effect of the Invention

[0017] According to the present invention, it is possible to suppress the generation of outgassing and to suppress deterioration of the optical properties of the cover glass. [Brief description of the drawings]

[0018] [Figure 1] 1 is a flowchart illustrating a method for manufacturing an electronic device according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a process diagram illustrating a cleaning and pretreatment step, a resin layer forming step, a transfer step, a curing step, a demolding step, and a post-curing step according to one embodiment of the present invention. [Diagram 3] FIG. 4 is a process diagram illustrating a baking process according to one embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an antireflection layer according to one embodiment of the present invention. [Diagram 5] FIG. 4 is a process diagram illustrating an assembly process according to one embodiment of the present invention. [Figure 6] FIG. 4 is a process diagram illustrating a reflow process according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0020] In the drawings referred to in the following description, the size of some components may be exaggerated for the sake of convenience. Therefore, the relative sizes of the components shown in the drawings do not necessarily accurately represent the actual size relationships between the components.

[0021] [1. Manufacturing methods for electronic devices] First, a method for manufacturing an electronic device 300 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a flow chart for explaining a method for manufacturing an electronic device 300 according to an embodiment of the present invention. FIG. 2 is a process diagram for explaining a cleaning and pretreatment step S110, a resin layer forming step S120, a transfer step S130, a curing step S140, a demolding step S150, and a post-curing step S160 according to an embodiment of the present invention. In FIG. 2, the treatment of the surface 14 is omitted for ease of understanding. FIG. 3 is a process diagram for explaining a baking step S170 according to an embodiment of the present invention. FIG. 4 is a diagram for explaining an anti-reflection layer 40 according to an embodiment of the present invention. FIG. 5 is a process diagram for explaining an assembly step S180 according to an embodiment of the present invention. FIG. 6 is a process diagram for explaining a reflow step S190 according to an embodiment of the present invention.

[0022] 1, the method for manufacturing an electronic device 300 according to this embodiment includes, for example, a cleaning and pretreatment step S110, a resin layer formation step S120, a transfer step S130, a curing step S140, a demolding step S150, a post-curing step S160, a baking step S170, an assembly step S180, and a reflow step S190. Each step will be described below.

[0023] [Cleaning and pretreatment step S110] First, clean the glass substrate 10. The glass substrate 10 is made of a transparent material such as non-alkali glass, borosilicate glass, quartz, or sapphire.

[0024] Then, as shown in FIG. 2, a surface 12 of the glass substrate 10 and a surface 14 opposite to the surface 12 are subjected to a pretreatment and a silane treatment.

[0025] The pretreatment is, for example, corona discharge surface treatment, blast surface treatment, plasma surface treatment, excimer surface treatment, flame surface treatment, etching, polishing, etc. The silane treatment is performed by spin-coating a primer on the surfaces 12, 14 of the glass substrate 10 and heating it. The primer is a silane coupling agent, such as "KBM5103", "KBM603", "KBM403", or "X-12-1048" manufactured by Shin-Etsu Chemical Co., Ltd.

[0026] [Resin layer forming process S120] 2, an uncured resin layer 20 is formed on both surfaces 12, 14 of a glass substrate 10. For example, the uncured resin layer 20 may be formed by applying an uncured photocurable resin to the surface 12 of the glass substrate 10 using a coating device (not shown). Alternatively, the uncured resin layer 20 may be formed by dropping an uncured photocurable resin onto the surface 12 of the glass substrate 10. In other words, the uncured resin layer 20 is made of an uncured photocurable resin.

[0027] The uncured photocurable resin contains, for example, a photopolymerization component and a photopolymerization initiator. The photopolymerization component contains a resin (A) and a resin (B). In this embodiment, the photopolymerization component is, for example, composed of a resin (A) and a resin (B). The resin (A) is a monofunctional acrylate monomer. The resin (B) is a difunctional or higher acrylate monomer.

[0028] In this embodiment, the content of resin (A) relative to all photopolymerizable components is more than 10 mass% and 40 mass% or less, and the content of resin (B) relative to all photopolymerizable components is 60 mass% or more and less than 90 mass%.

[0029] By making the content of resin (A) in the photopolymerization components equal to or less than the content of resin (B), it is possible to reduce the amount of outgassing in the reflow step S190 described below. In addition, when assembled into electronic device 300, it is possible to improve the parallel light transmittance of cover glass 100. Furthermore, it is possible to improve the heat resistance of antireflection layer 40 described below.

[0030] The resin (A) is a monofunctional acrylate monomer having a phenyl group. The resin (A) is, for example, either one or both of phenylethyl acrylate and benzyl acrylate. Since the resin (A) has a phenyl group, the carbon skeleton of the resin (A) is rigid. Therefore, by including the resin (A) in the photopolymerization component, the heat resistance of the antireflection layer 40 can be improved.

[0031] The resin (B) is preferably a difunctional or higher acrylate monomer having a cyclic structure in the molecule. When the photopolymerization component contains a difunctional or higher acrylate monomer having a cyclic structure in the molecule as the resin (B), the heat resistance can be improved.

[0032] Therefore, by including a bifunctional or higher functional acrylate monomer having a cyclic structure in the molecule as the resin (B) in the photopolymerization component, it is possible to reduce the amount of outgassing in the reflow step S190.

[0033] Resin (B) is preferably one or more monomers selected from the group consisting of dipentaerythritol hexaacrylate, 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxane-2-yl]-2,2-dimethylethyl acrylate, trimethylolpropane triacrylate, and 1,6-hexanediol diacrylate, and more preferably dipentaerythritol hexaacrylate and 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxane-2-yl]-2,2-dimethylethyl acrylate. As dipentaerythritol hexaacrylate, for example, "DPHA" manufactured by Nippon Kayaku Co., Ltd. can be used. Furthermore, as 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxane-2-yl]-2,2-dimethylethyl acrylate, for example, "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. can be used.

[0034] The photopolymerization initiator according to the present embodiment is, for example, an acylphosphine oxide-based photopolymerization initiator or an alkylphenone-based photopolymerization initiator. For example, "Irgacure 184" manufactured by IGM Resins BV can be used as the photopolymerization initiator.

[0035] The uncured photocurable resin may contain other components (additives), such as antioxidants, phosphors, plasticizers, UV absorbers, defoamers, thixotropic agents, polymerization inhibitors, release agents, metal oxide particles, etc.

[0036] [Transfer process S130] The transfer step S130 is a step of transferring the fine relief structure 32 of the master 30 to the uncured resin layer 20 provided on the surfaces 12 and 14 on both sides of the glass substrate 10.

[0037] As shown in FIG. 2, the master 30 is pressed against the uncured resin layer 20, and the fine concave-convex structure 32 of the master 30 is transferred to the uncured resin layer 20 to form the fine concave-convex structure 42 in the uncured resin layer 20. The average period of the concave-convex structures in the fine concave-convex structure 42 is equal to or less than the wavelength of visible light. Here, the average period of the concave-convex structures corresponds to the pitch between the plurality of convex portions (or the pitch between the plurality of concave portions) of the fine concave-convex structure 32. The average period of the concave-convex structures is set to be equal to or less than any wavelength within the wavelength band of visible light according to the desired antireflection properties of the antireflection layer 40 of the cover glass 100. For example, when the wavelength band of visible light is 360 nm to 830 nm, the average period of the concave-convex structures may be, for example, 830 nm or less or 360 nm or less. In the present embodiment, the master 30 is preferably formed of a material that can transmit light (for example, ultraviolet light).

[0038] [Curing process S140] The curing step S140 is a step of curing the uncured resin layer 20 to which the fine concave-convex structure 42 has been transferred by irradiating the uncured resin layer 20 with light.

[0039] As described above, in this embodiment, the master 30 is made of a material that can transmit light. Therefore, as shown in Fig. 2, the master 30 is pressed against the uncured resin layer 20, and the uncured resin layer 20 is irradiated with light. This causes the uncured resin layer 20 on the glass substrate 10 to cure. That is, in this embodiment, the transfer step S130 and the curing step S140 are performed simultaneously (in parallel).

[0040] [Mold release process S150] After the uncured resin layer 20 is cured, the master 30 is released from the cured uncured resin layer 22 . [Post-curing process S160] The uncured resin layer 22 after demolding is further irradiated with light to promote curing of the uncured resin layer 22.

[0041] In this way, as shown in FIG. 3, an antireflection layer 40 is formed on the surface 12 of the glass substrate 10, which is made of the cured product 24 of the photocurable resin and has a fine concave-convex structure 42 with an average period of concave-convex structures equal to or shorter than the wavelength of visible light.

[0042] 4, the fine uneven structure 42 may be, for example, a so-called moth-eye structure. For example, the convex portions and concave portions of the fine uneven structure 42 are arranged in the X direction and the Y direction on the surface 12 (XY plane) of the glass substrate 10. The fine uneven structure 42 formed on the surface of the antireflection layer 40 can impart an antireflection function to the cover glass 100 according to the average period of the concaves and convexes of the fine uneven structure 42.

[0043] As shown in FIG. 3, in this embodiment, the other surface 14 (rear surface) of the glass substrate 10 is subjected to a treatment similar to the treatment for the surface 12 described above, to form an antireflection layer 40 on the other surface 14.

[0044] In this manner, a cover glass 100 is manufactured in which the anti-reflection layer 40 is formed on both surfaces 12, 14 of the glass substrate 10. However, the present invention is not limited to this example, and the anti-reflection layer 40 may be formed on only one surface of the glass substrate 10.

[0045] [Baking process S170] The baking step S170 is a step of heating the cover glass 100. The baking step S170 is a step of performing a heat treatment as a pretreatment for the reflow step S190 described later. In this embodiment, in the baking step S170, the cover glass 100 is heated at a temperature of 150° C. or more and less than 250° C. for 10 minutes or more.

[0046] If the heating temperature of the cover glass 100 is less than 150° C., a small amount of outgassing originating from the photopolymerization component contained in the antireflection layer 40 (hereinafter, may be simply referred to as "monomer-derived outgassing") is generated. In other words, if the heating temperature of the cover glass 100 is less than 150° C., a large amount of the photopolymerization component contained in the antireflection layer 40 remains. In this case, a large amount of monomer-derived outgassing is generated when the reflow step S190 is performed.

[0047] Therefore, in the baking step S170, by heating the cover glass 100 at a temperature of 150° C. or higher, it is possible to favorably generate monomer-derived outgassing from the antireflection layer 40 and reduce the amount of remaining photopolymerization components contained in the antireflection layer 40. This makes it possible to reduce the amount of monomer-derived outgassing from the cover glass 100 in the subsequent reflow step S190.

[0048] On the other hand, if the heating temperature of the cover glass 100 is 250° C. or higher, the antireflection layer 40 constituting the cover glass 100 is denatured, and the parallel light transmittance of the cover glass 100 decreases.

[0049] Therefore, in this embodiment, in the baking step S170, the cover glass 100 is heated to a temperature less than 250° C. This makes it possible to prevent a decrease in the parallel ray transmittance of the cover glass 100 after the baking step S170 is performed.

[0050] Specifically, when the baking step S170 of the cover glass 100 is performed, the parallel ray transmittance of the cover glass 100 for light with a wavelength of 400 nm is, for example, 96% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 550 nm is, for example, 98% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 650 nm is, for example, 98.5% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 900 nm is, for example, 98% or more.

[0051] The parallel beam transmittance is calculated based on the following formula (1). Parallel transmittance [%]=(I / I0)×100…Formula (1)

[0052] In the above formula (1), I0 is the intensity of the parallel rays incident on the cover glass 100. Furthermore, I is the intensity of the parallel rays transmitted through the cover glass 100.

[0053] Furthermore, if the heating time of the cover glass 100 in the baking step S170 is less than 10 minutes, a small amount of outgassing derived from the monomer contained in the antireflection layer 40 is generated. In other words, if the heating time of the cover glass 100 is less than 10 minutes, a large amount of the photopolymerization component remains in the antireflection layer 40. As a result, a large amount of outgassing derived from the monomer is generated when the reflow step S190 is performed.

[0054] Therefore, in the baking step S170, the cover glass 100 is heated for 10 minutes or more to reduce the amount of remaining photopolymerization component contained in the antireflection layer 40. This makes it possible to reduce the amount of monomer-derived outgassing in the subsequent reflow step S190.

[0055] The heating time of the cover glass 100 in the baking step S170 is preferably 60 minutes or less. Even if the heating time of the cover glass 100 exceeds 60 minutes, the amount of monomer-derived outgassing generated is almost the same as when the heating time is 60 minutes, and the energy required for heating for more than 60 minutes is wasted. Therefore, by setting the heating time of the cover glass 100 in the baking step S170 to 60 minutes or less, it is possible to reduce the energy required for heating while ensuring the amount of monomer-derived outgassing generated, thereby improving energy efficiency.

[0056] Through the above steps, the cover glass 100 according to this embodiment is manufactured. The cover glass 100 comprises a glass substrate 10 and an antireflection layer 40 provided on surfaces 12, 14 on both sides of the glass substrate 10. The antireflection layer 40 has a fine uneven structure 42 in which the average period of the unevenness is equal to or shorter than the wavelength of visible light, and is made of a cured product 24 of a photocurable resin. The cured product 24 of the photocurable resin is a polymer of resin (A) and resin (B).

[0057] The content of the residual monomer derived from the photopolymerization component contained in the polymer is preferably 0.3 mass% or less. This allows the parallel beam transmittance of the cover glass 100 to be maintained high, and also allows the amount of monomer-derived outgassing to be reduced in the reflow step S190. The content of the residual monomer derived from the resin (A) contained in the polymer is preferably 0.25 mass% or less. This allows the parallel beam transmittance of the cover glass 100 to be maintained even higher, and also allows the amount of monomer-derived outgassing to be reduced in the reflow step S190.

[0058] [Assembly process S180] In the assembly process S180, the cover glass 100 after the baking process S170 is placed in a position facing the light receiving surface 222 of the sensor element 220, and the sensor module 200 is assembled.

[0059] 5, in the assembly process S180 of this embodiment, the cover glass 100 is placed on the sensor unit 210 to assemble the sensor module 200. The sensor unit 210 includes a sensor element 220 and a package substrate 230.

[0060] The sensor element 220 is, for example, an image sensor, a LiDAR, etc. The image sensor is, for example, a visible light image sensor, an infrared image sensor, an ultraviolet image sensor, an X-ray image sensor, etc. The image sensor may be, for example, a CCD image sensor, a CMOS image sensor, etc.

[0061] The package substrate 230 is, for example, a ball grid array. In this embodiment, the package substrate 230 includes an accommodating portion 232, a printed circuit board 234, and solder balls 236. The accommodating portion 232 accommodates the printed circuit board 234. The accommodating portion 232 is formed of, for example, epoxy resin. The multiple solder balls 236 are provided on a lower surface of the accommodating portion 232. The multiple solder balls 236 are connected to the printed circuit board 234 by wiring (not shown).

[0062] The sensor element 220 is mounted on a printed circuit board 234. In this embodiment, the surface of the sensor element 220 opposite to the light receiving surface 222 is in contact with the printed circuit board 234. The sensor element 220 and the printed circuit board 234 are connected by a bonding wire 234a.

[0063] 5, in the assembly process S180 according to the present embodiment, the cover glass 100 is placed on the upper part of the accommodation portion 232 of the package substrate 230, and the cover glass 100 and the sensor element 220 are arranged facing each other while being spaced apart, to assemble the sensor module 200. However, the assembly mode of the sensor module 200 is not limited to the example of FIG. 5, and other assembly modes may be used as long as the cover glass 100 is placed in a position facing the light receiving surface 222 of the sensor element 220.

[0064] [Reflow process S190] The reflow process S190 is a process in which the sensor module 200 is placed on the mounting substrate 250 and heated at a temperature of 250° C. or higher. In this embodiment, the reflow process S190 is performed by housing the sensor module 200 placed on the mounting substrate 250 in a reflow furnace RF. The temperature inside the reflow furnace RF is then set to 250° C. or higher.

[0065] The heat treatment in the reflow process S190 melts the multiple solder balls 236 of the sensor module 200, and the sensor module 200 is soldered to the mounting board 250. In this way, the electronic device 300 is manufactured. In the electronic device 300, the sensor element 220 covered with the cover glass 100 is mounted on the mounting board 250.

[0066] As described above, according to this embodiment, the baking step S170 is performed as a heating step prior to the reflow step S190. As a result, in the reflow step S190, the rate of outgassing generated from the antireflection layer 40 of the cover glass 100 and originating from the photopolymerization component is 0.3 mass % or less relative to the mass of the antireflection layer 40. In addition, in the reflow step S190, the rate of outgassing generated from the antireflection layer 40 of the cover glass 100 and originating from the resin (A) is preferably less than 0.2 mass % relative to the mass of the antireflection layer 40.

[0067] The outgassing rate is calculated based on the following formulas (2) and (3) by analyzing the outgassing generated by heating the antireflection layer 40 to 265° C. using a gas chromatography mass spectrometer (GC-MS). OGt[mass%]=PAt×S[mg] / PAs / C[mg]×100…Equation (2) OGa[mass%]=PAa×S[mg] / PAs / C[mg]×100…Equation (3)

[0068] In the above formula (2), OGt is the generation rate [mass %] of outgassing derived from the photopolymerization component. PAt is the peak area of ​​outgassing derived from the photopolymerization component obtained by gas chromatography mass spectrometer. In the above formulas (2) and (3), PAs is the peak area of ​​a standard substance (e.g., tetradecane) obtained by gas chromatography mass spectrometer. S is the weight [mg] of the standard substance added during measurement. C is the weight [mg] of the antireflection layer 40. In the above formula (3), OGa is the generation rate [mass %] of outgassing derived from the resin (A). PAa is the peak area of ​​outgassing derived from the resin (A) obtained by gas chromatography mass spectrometer.

[0069] As described above, in the manufacturing method of the electronic device 300 according to this embodiment, by using a monofunctional acrylate monomer having a phenyl group as the resin (A) and performing the baking step S170 prior to the reflow step S190, it is possible to reduce the generation rate of outgassing originating from the photopolymerization component among the outgassing generated from the antireflection layer 40 of the cover glass 100 in the reflow step S190 to 0.3 mass % or less relative to the mass of the antireflection layer 40.

[0070] This makes it possible to suppress the generation of outgassing that may induce corrosion of wiring materials, etc. in the electronic device 300 during a high-temperature reflow process (for example, 250 to 270° C.). This makes it possible to suppress corrosion of the sensor element 220 of the electronic device 300, the printed circuit board 234, the bonding wires 234a, and various wirings provided on the mounting board 250, etc.

[0071] In addition, deterioration of the optical properties of the cover glass 100 caused by outgassing, such as yellowing of the cover glass 100 (deterioration of the short wavelength side transmittance) and deterioration of the anti-reflection performance (sagging of the fine uneven structure 42), can be suppressed. Therefore, it is possible to improve the parallel ray transmittance of the cover glass 100 in the electronic device 300, and high transmission performance of the cover glass 100 for light with a wavelength of 400 nm or more can be ensured. In this way, by improving the transmission performance of the cover glass 100, the imaging performance of an image sensor or the like covered with the cover glass 100 can be improved.

[0072] Conventionally, when cover glass is made of a resin material, there is a problem that the transmittance drops for light in the visible light region on the short wavelength side. In contrast, the cover glass 100 according to the present embodiment suppresses the drop in transmittance for light in the visible light region on the short wavelength side, and ensures high transmittance for light with a wavelength of 400 nm or more.

[0073] Specifically, when the reflow step S190 of the cover glass 100 is performed, the parallel ray transmittance of the cover glass 100 for light with a wavelength of 400 nm is, for example, 95.5% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 550 nm is, for example, 98% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 650 nm is, for example, 98.5% or more. The parallel ray transmittance of the cover glass 100 for light with a wavelength of 900 nm is, for example, 98% or more.

[0074] This allows the incident light from the outside to pass through the highly transmittance cover glass 100 satisfactorily and reach the sensor element 220. This makes it possible to suppress the decrease in the light receiving sensitivity of the sensor element 220 caused by using the resin cover glass 100.

[0075] In addition, it is possible to prevent the light reflected by the sensor element 220 from being reflected again by the cover glass 100. This makes it possible to prevent erroneous reactions of the sensor element 220 caused by re-reflection by the cover glass 100.

[0076] As described above, the parallel ray transmittance of the cover glass 100 after the reflow process S190 is performed, that is, the cover glass 100 of the electronic device 300, for light with a wavelength of 400 nm is, for example, 95.5% or more. Therefore, the cover glass 100 can be applied to the sensor element 220 that receives not only visible light but also infrared light.

[0077] Furthermore, by using a monofunctional acrylate monomer having a phenyl group as the resin (A), the heat resistance of the antireflection layer 40 can be improved. Therefore, deformation of the fine uneven structure 42 of the antireflection layer 40 can be suppressed. This makes it possible to avoid a decrease in the antireflection performance of the antireflection layer 40.

[0078] In addition, by using a monomer having a cyclic structure in the molecule as resin (B), the rate of outgassing originating from the photopolymerization component among the outgassing generated from the antireflection layer 40 of the cover glass 100 in the reflow process S190 can be further reduced. EXAMPLES

[0079] Examples and comparative examples of the present invention will be described in detail below. Note that the examples shown below are merely examples, and the method for manufacturing an electronic device and the cover glass according to the present invention are not limited to the following examples.

[0080] [Photopolymerization component] As the cover glasses, Examples 1 to 8 and Comparative Examples 1 to 4 were prepared.

[0081] [Example 1] An uncured photocurable resin composition was prepared by mixing the photopolymerization components and the photopolymerization initiator. Resin (A) and resin (B) were used as the photopolymerization components.

[0082] The resin (A) used was phenylethyl acrylate (PEA) manufactured by Osaka Organic Chemical Industry Co., Ltd. The viscosity of PEA at 25°C was 8.4 mPa·s.

[0083] As resin (B), "DPHA" and "KAYARAD R-604" manufactured by Nippon Kayaku Co., Ltd. were used. The viscosity of "DPHA" at 25°C was 5440 mPa·s. The viscosity of "KAYARAD R-604" at 25°C was 338 mPa·s.

[0084] "Irgacure 184" manufactured by IGM Resins BV was used as the photopolymerization initiator.

[0085] In Example 1, the content of resin (A) was 20% by mass, and the content of resin (B) was 80% by mass. In addition, in resin (B), the content of "DPHA" was 30% by mass, and the content of "KAYARAD R-604" was 50% by mass. The content of the photopolymerization initiator was 3% by mass.

[0086] The glass substrate 10 was spin-coated with a primer and heated on a hot plate at 150° C. for 4 minutes.

[0087] The uncured photocurable resin composition was potted on the primer-treated glass substrate 10, and the master 30 was placed on top of the uncured photocurable resin composition, after which the transfer step S130 and the curing step S140 were carried out using an imprinting device. The transfer step S130 and the curing step S140 were carried out under a constant temperature condition of 40°C.

[0088] First, in the transfer step S130, the master 30 was pressurized to 1000 N over 30 seconds, and then the pressure of 1000 N was maintained for 30 seconds. Then, in the curing step S140, the photocurable resin composition was exposed to light using an LED lamp, and the pressure was released over 10 seconds. Next, the master 30 was released from the photocurable resin composition on the glass substrate 10, and then the photocurable resin composition on the glass substrate 10 was cured by applying 1000 mJ / cm 2 of UV light using a UV conveyor. 2 The photocurable resin composition was cured by exposure to light at 1000 W. As a result, an antireflection layer 40 made of a cured product 24 of the photocurable resin composition and having a fine uneven structure 42 was formed on the glass substrate 10, and a cover glass 100 was obtained.

[0089] Next, a baking step S170 was performed. In the baking step S170, the cover glass 100 was heated at 150° C. for 30 minutes using a hot plate. The cover glass 100 according to Example 1 was manufactured by the above steps. Then, a reflow step S190 was performed. In the reflow step S190, the cover glass 100 was heated at 265° C. for 5 minutes. In addition, after the reflow step S190, a reliability test was performed. In the reliability test, the cover glass 100 was heated at 125° C. for 2000 hours.

[0090] [Example 2] Cover glass 100 according to Example 2 was produced in the same manner as in Example 1, except for the content of resin (A) and the content of resin (B) in the photopolymerizable components.

[0091] In Example 2, the content of resin (A) was 30% by mass, and the content of resin (B) was 70% by mass. In addition, in resin (B), the content of "DPHA" was 40% by mass, and the content of "KAYARAD R-604" was 30% by mass.

[0092] [Example 3] Cover glass 100 according to Example 3 was produced in the same manner as in Example 1, except for the content of resin (A) and the content of resin (B) in the photopolymerizable components.

[0093] In Example 3, the content of resin (A) was 40% by mass, and the content of resin (B) was 60% by mass. In addition, in resin (B), the content of "DPHA" was 30% by mass, and the content of "KAYARAD R-604" was 30% by mass.

[0094] [Example 4] Cover glass 100 according to Example 4 was produced in the same manner as in Example 3, except for the resin (A) in the photopolymerization components.

[0095] In Example 4, benzyl acrylate (BZA) manufactured by Osaka Organic Chemical Industry Ltd. was used as the resin (A).

[0096] [Example 5] A cover glass 100 according to Example 5 was produced in the same manner as in Example 2, except for the resin (B) in the photopolymerization components.

[0097] In Example 5, trimethylolpropane triacrylate (TMPTA) manufactured by Miwon Specialty Chemical Co., Ltd. and 1,6-hexanediol diacrylate (HDDA) manufactured by Miwon Specialty Chemical Co., Ltd. were used as resin (B). The viscosity of TMPTA at 25°C was 120 mPa s. The viscosity of HDDA at 25°C was 6.9 mPa s.

[0098] In the resin (B), the content of TMPTA was 40 mass %, and the content of HDDA was 30 mass %.

[0099] [Example 6] Cover glass 100 according to Example 6 was produced in the same manner as in Example 3, except for the resin (B) in the photopolymerization components.

[0100] In Example 6, similarly to Example 5, trimethylolpropane triacrylate (TMPTA) manufactured by Miwon Specialty Chemical Co., Ltd. and 1,6-hexanediol diacrylate (HDDA) manufactured by Miwon Specialty Chemical Co., Ltd. were used as the resin (B).

[0101] In the resin (B), the content of TMPTA was 30 mass %, and the content of HDDA was 30 mass %.

[0102] [Example 7] Cover glass 100 according to Example 7 was produced in the same manner as in Examples 2 and 5, except for the resin (B) in the photopolymerization component.

[0103] In Example 7, "DPHA" manufactured by Nippon Kayaku Co., Ltd. and 1,6-hexanediol diacrylate (HDDA) manufactured by Miwon Specialty Chemical Co., Ltd. were used as the resin (B).

[0104] In the resin (B), the content of "DPHA" was set to 40 mass %, and the content of HDDA was set to 30 mass %.

[0105] [Example 8] Cover glass 100 according to Example 8 was produced in the same manner as in Examples 3 and 6, except for the resin (B) in the photopolymerization component.

[0106] In Example 8, "DPHA" manufactured by Nippon Kayaku Co., Ltd. and 1,6-hexanediol diacrylate (HDDA) manufactured by Miwon Specialty Chemical Co., Ltd. were used as resin (B).

[0107] In the resin (B), the content of "DPHA" was set to 30 mass %, and the content of HDDA was set to 30 mass %.

[0108] [Comparative Example 1] A cover glass according to Comparative Example 1 was produced in the same manner as in Example 1, except for the content of resin (A) and the content of resin (B) in the photopolymerizable components.

[0109] In Comparative Example 1, the content of resin (A) was 10% by mass, and the content of resin (B) was 90% by mass. In addition, in resin (B), the content of "DPHA" was 50% by mass, and the content of "KAYARAD R-604" was 40% by mass.

[0110] [Comparative Example 2] A cover glass according to Comparative Example 2 was produced in the same manner as in Example 3, except for the resin (A) in the photopolymerization components.

[0111] In Comparative Example 2, dicyclopentanyl methacrylate "FA513M" manufactured by Showa Denko Materials Co., Ltd. was used as the photopolymerization component instead of resin (A). The viscosity of "FA513M" at 25°C was 11 mPa s. In Comparative Example 2, the content of "FA513M" was 40 mass%.

[0112] [Comparative Example 3] A cover glass according to Comparative Example 3 was produced in the same manner as in Example 2, except for the resin (A) in the photopolymerization components.

[0113] In Comparative Example 3, instead of the resin (A), phenylethyl methacrylate (PEMA) manufactured by Tokyo Chemical Industry Co., Ltd. was used as the photopolymerization component. In Comparative Example 3, the content of PEMA was 30 mass %.

[0114] [Comparative Example 4] A cover glass according to Comparative Example 4 was produced in the same manner as in Example 3, except for the resin (A) in the photopolymerization components.

[0115] In Comparative Example 4, instead of the resin (A), phenylethyl methacrylate (PEMA) manufactured by Tokyo Chemical Industry Co., Ltd. was used as the photopolymerization component. In Comparative Example 4, the content of PEMA was 40 mass %.

[0116] [Measurement of outgas generation rate] In the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, the outgassing generated by carrying out the reflow step S190 was analyzed by a gas chromatography mass spectrometer (GC-MS). Then, the generation rate [mass %] of outgassing derived from the photopolymerization component was calculated using the above-mentioned formula (2). Moreover, in Examples 1 to 8 and Comparative Example 1, the generation rate [mass %] of outgassing derived from the resin (A) was calculated using the above-mentioned formula (3). In Comparative Examples 2 to 4, the generation rate [mass %] of outgassing derived from the monofunctional acrylate monomer or monofunctional methacrylate monomer was calculated using the above-mentioned formula (3).

[0117] [Parallel beam transmittance measurement] In the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, the parallel ray transmittance of the samples was measured after the baking step S170 and before the reflow step S190. Also, in the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, the parallel ray transmittance of the cover glass after the reflow step S190 was measured. Also, in the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, the parallel ray transmittance of the cover glass after the reliability test was performed was measured.

[0118] The parallel beam transmittance was measured using a UV-Visible-Near-Infrared Spectrophotometer V-770 manufactured by JASCO Corporation. The transmittance of the cover glass at wavelengths of 400 nm, 550 nm, 650 nm, and 900 nm was calculated using the above formula (1).

[0119] The outgassing rate [mass %] derived from all the photopolymerization components, the outgassing rate [mass %] derived from resin (A), and parallel ray transmittance for Examples 1 to 4 are shown in Table 1 below. The outgassing rate [mass %] derived from all the photopolymerization components, the outgassing rate [mass %] derived from resin (A), and parallel ray transmittance for Examples 5 to 8 are shown in Table 2 below. In Tables 1 and 2, "◎" indicates that the evaluation of each evaluation item is very good, and "◯" indicates that the evaluation is good.

[0120] [Table 1]

[0121] [Table 2]

[0122] As shown in Examples 1 to 3 in Table 1, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization components was extremely low at 0.115% or less. It was also confirmed that the outgas generation rate [mass%] derived from resin (A) was extremely low at 0.047% or less.

[0123] Also, as shown in Examples 1 to 3, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high, at 97.3% or more. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high, at 96.9% or more. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high, at 95.6% or more.

[0124] In addition, as shown in Examples 1 to 3, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) was reduced to 0.44% or less. In addition, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test) was reduced to 1.91% or less. In other words, it was confirmed that the heat resistance of the antireflection layer 40 can be improved by using PEA as the resin (A) and "DPHA" and "KAYARAD R-604" as the resin (B).

[0125] Furthermore, as shown in Examples 2 and 3 in Table 1, it was confirmed that by setting the content of "DPHA" in resin (B) to be equal to or greater than the content of "KAYARAD R-604", the outgassing rate [mass%] of the entire photopolymerization components was further reduced to 0.079% or less. In other words, when the results of Example 1 are compared with the results of Examples 2 and 3, it was confirmed that by setting the content of "DPHA" in resin (B) to be equal to or greater than the content of "KAYARAD R-604", the outgassing rate [mass%] of the entire photopolymerization components could be further reduced.

[0126] As shown in Example 4 of Table 1, it was confirmed that by using BZA as resin (A), the outgas generation rate [mass%] of the entire photopolymerization component was reduced to 0.163%. In addition, it was confirmed that the outgas generation rate [mass%] derived from resin (A) was reduced to 0.055%. In addition, when the results of Example 4 and Example 3 are compared, it was confirmed that by using PEA as resin (A), the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) can be reduced more than when BZA is used as resin (A).

[0127] As shown in Example 4, by using BZA as the resin (A), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 96.3%, the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 95.5%, and the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 95.3%.

[0128] Moreover, as shown in Example 4, by using BZA as the resin (A), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) was reduced to 0.78%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test) was reduced to 1.02%. Furthermore, when the results of Example 4 are compared with those of Example 3, it was confirmed that the use of BZA as resin (A) can reduce the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190 - parallel ray transmittance [%] at 400 nm after the reliability test) more than the use of PEA as resin (A).

[0129] Also, as shown in Example 5 of Table 2, it was confirmed that by using PEA as resin (A) and TMPTA and HDDA as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component was reduced to 0.148%. Also, it was confirmed that the outgas generation rate [mass%] derived from resin (A) was reduced to 0.082%. In addition, when comparing the results of Example 5 with the results of Example 2, it was confirmed that by using "DPHA" and "KAYARAD R-604" as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) can be reduced more than by using TMPTA and HDDA as resin (B). In other words, it was confirmed that by using a monomer having a cyclic structure in the molecule as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) can be reduced.

[0130] Also, as shown in Example 5, by using PEA as resin (A) and TMPTA and HDDA as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.5%. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 97.1%. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 97.1%.

[0131] Also, as shown in Example 5, by using PEA as resin (A) and TMPTA and HDDA as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) was as low as 0.40%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test) was as low as 0.45%.

[0132] As shown in Example 6 of Table 2, it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization component was reduced to 0.136% by using PEA as resin (A) and TMPTA and HDDA as resin (B). It was also confirmed that the outgas generation rate [mass%] derived from resin (A) was reduced to 0.061%. In addition, when the results of Example 6 were compared with the results of Example 3, it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) could be reduced by using "DPHA" and "KAYARAD R-604" as resin (B) compared to using TMPTA and HDDA as resin (B). In other words, it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) could be reduced by using a monomer having a cyclic structure in the molecule as resin (B).

[0133] Also, as shown in Example 6, by using PEA as resin (A) and TMPTA and HDDA as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.5%. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 97.1%. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 97.0%.

[0134] In addition, as shown in Example 6, by using PEA as resin (A) and TMPTA and HDDA as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) was reduced to 0.41%. In addition, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test) was reduced to 0.46%.

[0135] As shown in Example 7 of Table 2, it was confirmed that by using PEA as resin (A) and "DPHA" and HDDA as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component was reduced to 0.163%. It was also confirmed that the outgas generation rate [mass%] derived from resin (A) was reduced to 0.102%. In addition, when the results of Example 7 and Example 2 were compared, it was confirmed that by using "KAYARAD R-604" in addition to "DPHA" as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) could be reduced more than by using HDDA in addition to "DPHA" as resin (B).

[0136] Also, as shown in Example 7, by using PEA as resin (A) and "DPHA" and HDDA as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.3%. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 96.9%. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 96.5%.

[0137] Also, as shown in Example 7, by using PEA as resin (A) and "DPHA" and HDDA as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reflow step S190) was as low as 0.40%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reliability test) was as low as 0.79%.

[0138] As shown in Example 8 of Table 2, it was confirmed that by using PEA as resin (A) and "DPHA" and HDDA as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component was reduced to 0.177%. It was also confirmed that the outgas generation rate [mass%] derived from resin (A) was reduced to 0.082%. In addition, when the results of Example 8 and Example 3 were compared, it was confirmed that by using "KAYARAD R-604" in addition to "DPHA" as resin (B), the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from resin (A) could be reduced more than by using HDDA in addition to "DPHA" as resin (B).

[0139] Also, as shown in Example 8, by using PEA as resin (A) and "DPHA" and HDDA as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.5%. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 96.5%. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 96.9%.

[0140] Also, as shown in Example 8, by using PEA as resin (A) and "DPHA" and HDDA as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reflow step S190) was as low as 1.00%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reliability test) was as low as 0.58%.

[0141] As shown in Examples 1 to 4 in Table 1 and Examples 5 to 8 in Table 2, the parallel ray transmittance of the sample after the baking step S170 and before the reflow step S190 was high at 98.3% or more for light with wavelengths of 550 nm, 650 nm, and 900 nm. The parallel ray transmittance of the sample after the reflow step S190 was high at 98.1% or more for light with wavelengths of 550 nm, 650 nm, and 900 nm. The parallel ray transmittance of the sample after the reliability test was high at 98.0% or more for light with wavelengths of 550 nm, 650 nm, and 900 nm.

[0142] The generation rates [mass %] of outgassing derived from the monofunctional monomer and the parallel beam transmittance of Comparative Examples 1 to 4 are shown in the following Table 3. In Table 3, "◎" indicates that the evaluation of each evaluation item is very good, "◯" indicates that the evaluation is good, and "×" indicates that the evaluation is poor.

[0143] [Table 3]

[0144] As shown in Comparative Example 1 of Table 3, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization components was reduced to 0.149% or less. It was also confirmed that the outgas generation rate [mass%] derived from resin (A) was extremely low at 0.036% or less.

[0145] Also, as shown in Comparative Example 1, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.9%. Also, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 97.3%. On the other hand, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was low at 95.1%.

[0146] In addition, as shown in Comparative Example 1, by using PEA as resin (A) and "DPHA" and "KAYARAD R-604" as resin (B), it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow process S190 compared to before the reflow process S190 (parallel ray transmittance at 400 nm before the reflow process S190 - parallel ray transmittance at 400 nm after the reflow process S190) was low at 0.64% or less. On the other hand, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow process S190 (parallel ray transmittance at 400 nm before the reflow process S190 - parallel ray transmittance at 400 nm after the reliability test) was high at 2.82%.

[0147] Comparing the results of Comparative Example 1 with the results of Examples 1 to 3, it was confirmed that when the content of resin (A) was 10% or less, the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was low. It was also confirmed that when the content of resin (A) was 10% or less, the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190 - parallel ray transmittance [%] at 400 nm after the reliability test) was high.

[0148] In addition, as shown in Comparative Example 2 of Table 3, it was confirmed that by using "FA513M" as the monofunctional acrylate monomer, the outgas generation rate [mass%] of the entire photopolymerization component was increased to 0.611%. In addition, it was confirmed that the outgas generation rate [mass%] derived from the monofunctional acrylate monomer was increased to 0.461%.

[0149] Also, as shown in Comparative Example 2, by using "FA513M" as the monofunctional acrylate monomer, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 98.5%. On the other hand, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was low at 95.2%. Furthermore, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was low at 93.1%.

[0150] In addition, as shown in Comparative Example 2, by using "FA513M" as the monofunctional acrylate monomer, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reflow step S190) was high at 3.39%. In addition, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 - parallel ray transmittance at 400 nm after the reliability test) was high at 5.39%.

[0151] Comparing the results of Comparative Example 2 with those of Example 3, it was confirmed that the use of a monofunctional acrylate monomer having no phenyl group increases the outgas generation rate [mass%] of the entire photopolymerization component and the outgas generation rate [mass%] derived from the monofunctional acrylate monomer. It was also confirmed that the use of a monofunctional acrylate monomer having no phenyl group reduces the parallel ray transmittance [%] at 400 nm of the sample after the reflow step S190 and the parallel ray transmittance [%] at 400 nm of the sample after the reliability test. Furthermore, it was confirmed that when a monofunctional acrylate monomer having no phenyl group is used, the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) and the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test [%]) are higher. In other words, it was confirmed that the heat resistance of the antireflection layer 40 is lower when a monofunctional acrylate monomer having no phenyl group is used than when a monofunctional acrylate monomer having a phenyl group is used.

[0152] As shown in Comparative Example 3 of Table 3, it was confirmed that by using PEMA as a monofunctional monomer, the outgas generation rate [mass%] of the entire photopolymerization components was increased to 0.316%. In addition, it was confirmed that the outgas generation rate [mass%] derived from the resin (A) was increased to 0.238%.

[0153] Also, as shown in Comparative Example 3, by using PEMA as the monofunctional monomer, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.4%, the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 95.7%, and the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 95.4%.

[0154] On the other hand, as shown in Comparative Example 3, by using PEMA as the monofunctional monomer, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm [%] before the reflow step S190-parallel ray transmittance at 400 nm after the reflow step S190) was as high as 1.75%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm [%] before the reflow step S190-parallel ray transmittance at 400 nm after the reliability test) was as high as 2.06%.

[0155] Comparing the results of Comparative Example 3 with those of Example 2, it was confirmed that when a monofunctional methacrylate monomer having a phenyl group was used as the monofunctional monomer, the outgassing generation rate [mass %] of the entire photopolymerization components and the outgassing generation rate [mass %] derived from the monofunctional monomer were higher than when a monofunctional acrylate monomer having a phenyl group was used. In addition, it was confirmed that when a monofunctional methacrylate monomer is used as the monofunctional monomer, the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reflow step S190 [%]) and the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%] - parallel ray transmittance at 400 nm after the reliability test [%]) are higher. In other words, it was confirmed that the heat resistance of the antireflection layer 40 is lower when a monofunctional methacrylate monomer having a phenyl group is used than when a monofunctional acrylate monomer having a phenyl group is used.

[0156] As shown in Comparative Example 4 of Table 3, it was confirmed that by using PEMA as a monofunctional monomer, the outgas generation rate [mass%] of the entire photopolymerization components was increased to 0.306%. In addition, it was confirmed that the outgas generation rate [mass%] derived from the resin (A) was increased to 0.234%.

[0157] Also, as shown in Comparative Example 4, by using PEMA as the monofunctional monomer, it was confirmed that the parallel ray transmittance [%] at 400 nm of the sample before the reflow process S190 was high at 97.5%, the parallel ray transmittance [%] at 400 nm of the sample after the reflow process S190 was high at 96.4%, and the parallel ray transmittance [%] at 400 nm of the sample after the reliability test was high at 96.5%.

[0158] On the other hand, as shown in Comparative Example 4, by using PEMA as a monofunctional monomer, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190-parallel ray transmittance [%] at 400 nm after the reflow step S190) was as high as 1.15%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190-parallel ray transmittance [%] at 400 nm after the reliability test) was 0.99%.

[0159] Comparing the results of Comparative Example 4 and Example 3, it was confirmed that the outgas generation rate [mass%] of the entire photopolymerization components and the outgas generation rate [mass%] derived from the monofunctional monomer were higher when a monofunctional methacrylate monomer having a phenyl group was used than when a monofunctional acrylate monomer having a phenyl group was used. It was also confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 was performed compared to before the reflow step S190 was performed (parallel ray transmittance at 400 nm [%] before the reflow step S190 - parallel ray transmittance at 400 nm after the reflow step S190) was higher when a monofunctional methacrylate monomer having a phenyl group was used than when a monofunctional acrylate monomer having a phenyl group was used. In other words, it was confirmed that the heat resistance of the antireflection layer 40 was lowered when a monofunctional methacrylate monomer having a phenyl group was used than when a monofunctional acrylate monomer having a phenyl group was used.

[0160] As described above, according to this embodiment, it is possible to reduce the generation rate of outgassing derived from the photopolymerization component while maintaining a high parallel ray transmittance of the cover glass 100. Therefore, the method for manufacturing the electronic device 300 according to this embodiment can maintain a high parallel ray transmittance of the cover glass 100 while suppressing corrosion of the electronic device 300.

[0161] [Study of baking process S170] The cover glasses were prepared according to Examples 9 to 15. Then, in the same manner as in the examination of the photopolymerizable component described above, the outgas generation rate and the parallel ray transmittance were measured.

[0162] [Example 9] Cover glass 100 according to Example 9 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was 180° C. and the heating time was 30 minutes.

[0163] [Example 10] Cover glass 100 according to Example 10 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 200° C. and the heating time was set to 10 minutes.

[0164] [Example 11] Cover glass 100 according to Example 11 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 200° C. and the heating time was set to 15 minutes.

[0165] [Example 12] Cover glass 100 according to Example 12 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 200° C. and the heating time was set to 30 minutes.

[0166] [Example 13] Cover glass 100 according to Example 13 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 230° C. and the heating time was set to 10 minutes.

[0167] [Example 14] Cover glass 100 according to Example 14 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 230° C. and the heating time was set to 15 minutes.

[0168] [Example 15] Cover glass 100 according to Example 15 was produced in the same manner as in Example 2, except that the heating temperature in baking step S170 was set to 230° C. and the heating time was set to 30 minutes.

[0169] The outgassing rate [mass%] derived from all the photopolymerization components, the outgassing rate [mass%] derived from resin (A), and the parallel ray transmittance of Examples 9 to 12 are shown in Table 4 below. The outgassing rate [mass%] derived from all the photopolymerization components, the outgassing rate [mass%] derived from resin (A), and the parallel ray transmittance of Examples 13 to 15 are shown in Table 5 below. In Tables 4 and 5, "◯" indicates that the evaluation of each evaluation item is good, and "◎" indicates that the evaluation is very good.

[0170] [Table 4]

[0171] [Table 5]

[0172] As shown in Example 9 of Table 4, it was confirmed that when the heating temperature in the baking step S170 was set to 180° C., the generation rate [mass %] of outgassing originating from the resin (A) was extremely low at 0.043%.

[0173] Moreover, as shown in Example 9, when the heating temperature in the baking step S170 is set to 180° C., it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190-parallel ray transmittance [%] at 400 nm after the reflow step S190) is extremely low at 0.29%. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190-parallel ray transmittance [%] at 400 nm after the reliability test) is low at 2.46%.

[0174] As shown in Examples 10 to 12 in Table 4, it was confirmed that as the heating time in the baking step S170 increases, the outgassing generation rate [mass %] derived from all the photopolymerizable components and the outgassing generation rate [mass %] derived from the resin (A) decrease.

[0175] Moreover, as shown in Examples 10 to 12, when the heating temperature in the baking step S170 is set to 200° C., it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%]-parallel ray transmittance at 400 nm after the reflow step S190 [%]) is extremely low, at 0.31% or less. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%]-parallel ray transmittance at 400 nm after the reliability test) is extremely low, at 0.52% or less.

[0176] Furthermore, when the results of Examples 10 to 12 are compared with the results of Example 2, it was confirmed that by increasing the heating temperature in the baking step S170, even if the heating time is shortened, the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190 - parallel ray transmittance [%] at 400 nm after the reliability test) can be reduced.

[0177] As shown in Examples 13 to 15 in Table 5, it was confirmed that as the heating time in the baking step S170 increases, the outgassing generation rate [mass %] derived from all the photopolymerizable components and the outgassing generation rate [mass %] derived from the resin (A) decrease.

[0178] Moreover, as shown in Examples 13 to 15, when the heating temperature in the baking step S170 is set to 230° C., it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reflow step S190 compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%]-parallel ray transmittance at 400 nm after the reflow step S190 [%]) is extremely low, at 0.21% or less. Also, it was confirmed that the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance at 400 nm before the reflow step S190 [%]-parallel ray transmittance at 400 nm after the reliability test) is extremely low, at 0.35% or less.

[0179] Furthermore, when the results of Examples 13 to 15 are compared with the results of Example 2, it was confirmed that by increasing the heating temperature in the baking step S170, even if the heating time was shortened, the variation rate [%] of the parallel ray transmittance at 400 nm after the reliability test compared to before the reflow step S190 (parallel ray transmittance [%] at 400 nm before the reflow step S190 - parallel ray transmittance [%] at 400 nm after the reliability test) can be reduced.

[0180] Although the embodiment of the present invention has been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that such examples also naturally belong to the technical scope of the present invention.

[0181] For example, in the above embodiment, the case has been described where the uncured resin layer 20 is cured by irradiating the uncured resin layer 20 with light while the fine relief structure 32 of the master 30 is transferred to the uncured resin layer 20. However, after the fine relief structure 32 of the master 30 is transferred to the uncured resin layer 20, the uncured resin layer 20 may be cured by irradiating the uncured resin layer 20 with light.

[0182] In the above embodiment, the outgassing rate derived from the photopolymerization component and the outgassing rate derived from the resin (A) are calculated using the analysis results obtained by a gas chromatography mass spectrometer (GC-MS). However, the outgassing rate derived from the photopolymerization component and the outgassing rate derived from the resin (A) may be calculated using other methods. [Explanation of symbols]

[0183] S130 Transfer process S140 hardening process S170 Baking process S180 assembly process S190 Reflow process 10 Glass substrate 12 Surface 14 Surface 20 Uncured resin layer 30 Master 32 Fine uneven structure 40 Anti-reflection layer 42 Fine uneven structure 100 Coverslips 200 Sensor Module 220 Sensor element 222 Photosensitive surface 250 Mounting Board 300 Electronic Devices

Claims

1. In a method for manufacturing an electronic device in which a sensor element covered with a cover glass is mounted on a mounting substrate, The aforementioned cover glass is Glass substrate and An anti-reflective layer provided on at least one surface of the glass substrate, having a fine uneven structure in which the average period of the unevenness is less than or equal to the wavelength of visible light, Equipped with, The aforementioned manufacturing method is (1) A transfer step of transferring the fine uneven structure of the master disc to an uncured resin layer made of an uncured photocurable resin provided on at least one surface of the glass substrate, (2) A curing step in which the uncured resin layer on which the fine uneven structure has been transferred is irradiated with light to cure the uncured resin layer and form the anti-reflective layer which is made of the cured product of the photocurable resin, (3) A baking step of heating the cover glass on which the anti-reflective layer has been formed, (4) An assembly step in which the cover glass after the baking process is placed at a position facing the light-receiving surface of the sensor element, and the sensor module is assembled, (5) A reflow step in which the sensor module is placed on the mounting substrate and heated at a temperature of 250°C or higher to solder the sensor module to the mounting substrate, Includes, The uncured photocurable resin is Contains photopolymerization components, The photopolymerization component comprises resin (A) and resin (B), The resin (A) is a monofunctional acrylate monomer consisting of either phenylethyl acrylate or benzyl acrylate, The resin (B) is one or more of two- or more functional acrylate monomers selected from the group consisting of dipentaerythritol hexaacrylate, 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxan-2-yl]-2,2-dimethylethyl acrylate, trimethylolpropane triacrylate, and 1,6-hexanediol diacrylate. The content of resin (A) relative to the total photopolymerization component is greater than 10% by mass and 40% by mass or less. The content of the resin (B) relative to the total photopolymerization component is 60% by mass or more and less than 90% by mass. A method for manufacturing an electronic device, comprising the baking step of heating the cover glass on which the anti-reflective layer is formed at a temperature of 150°C or higher and less than 250°C for 10 minutes or more.

2. The method for manufacturing an electronic device according to claim 1, wherein, in the reflow step, the generation rate of outgassing from the anti-reflective layer of the cover glass that originates from the resin (A) is less than 0.2% by mass.

3. The anti-reflective layer is provided on both sides of the glass substrate. The method for manufacturing an electronic device according to claim 1, wherein the transfer step involves transferring the fine uneven structure of the master disc to the uncured resin layers provided on both surfaces of the glass substrate.

4. The method for manufacturing an electronic device according to claim 1, wherein the sensor element is an image sensor.

5. A method for manufacturing an electronic device according to claim 1, wherein the baking step is performed before the reflow step such that, in the reflow step, the rate of outgassing generated from the anti-reflective layer of the cover glass, with the rate of outgassing originating from the photopolymerization component, is 0.3% by mass or less relative to the mass of the anti-reflective layer.

Images