Electronic device manufacturing method and glass plate group

Abstract

An electronic device manufacturing method according to the present invention comprises: a preparation step S1 for preparing a glass plate group Gg which includes a plurality of glass plates Gs; a device formation step S2 for forming electronic devices D on the glass plates Gs; and a separation step S3 for separating the glass plates Gs from resin layers 6 of the electronic devices D. The standard deviation of transmittance of the plurality of glass plates Gs at wavelengths of 308-355 nm is not more than 3.0.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electronic device such as an organic EL display, and to a group of glass plates used in this manufacturing method. [Background technology]

[0002] Organic EL devices used in flexible displays and the like are manufactured by using a resin layer such as polyimide as a substrate and forming a TFT layer, an organic EL layer, etc. on top of it. The resin layer is formed by applying a varnish-like composition to a glass plate (also called carrier glass) and then subjecting it to heat treatment for a certain period of time at or below the thermal decomposition temperature of the resin component (see, for example, Patent Document 1).

[0003] Once the organic EL device is formed on the resin layer, a peeling process is carried out to peel the organic EL device (resin layer) from the glass plate. In this peeling process, a laser is irradiated from the side opposite to the glass plate on which the organic EL device is formed, to heat the interface between the glass plate and the resin layer. Lasers that can be used include XeCl excimer laser (wavelength 308 nm), Nd-YAG solid state laser (wavelength 355 nm), and Yb-YAG solid state laser (wavelength 343 nm).

[0004] Organic EL devices manufactured through the above-described processes are flexible and have excellent device properties, and are therefore particularly used in the manufacture of flexible electronic devices such as displays, touch panels, and solar cells. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 073591 Summary of the Invention [Problem to be solved by the invention]

[0006] In the manufacturing process of electronic devices, a group of glass plates including a plurality of glass plates is prepared, and an organic EL device is sequentially formed on each glass plate. In the conventional manufacturing process, there are cases in which the resin layer of an organic EL device is not sufficiently peeled from the glass plate during the peeling process. Specifically, there are cases in which a part of the resin layer of the organic EL device does not peel from the glass plate and remains on the glass plate.

[0007] One way to solve this problem is to increase the intensity of the laser irradiation, but this method applies excessive thermal stress to the resin layer, and there is a risk that wrinkles (local film peeling) will occur in the resin substrate after the resin layer is peeled off from the glass plate due to residual stress between the resin layer (resin substrate) and the TFT layer.

[0008] Wrinkles in the resin substrate can cause malfunctions in the organic EL device, which can lead to lower yields and higher production costs in the manufacture of organic EL devices.

[0009] The present invention has as its technical object to make it difficult for wrinkles to occur in the resin layer of an electronic device when a glass plate is peeled off from the electronic device. [Means for solving the problem]

[0010] As a result of various investigations, the present inventors have found that in the process of irradiating the interface between a glass plate and a resin layer of an electronic device with a UV laser, by reducing the variation in transmittance at wavelengths of 308 to 355 nm for each glass plate in a group of glass plates to a certain value or less, it becomes easier to achieve a uniform heating state at the interface between the glass plate and the resin layer, thereby solving the above-mentioned problems, and have proposed this finding as the present invention.

[0011] That is, the present invention is a method for manufacturing an electronic device, comprising: a preparation step of preparing a glass plate group including a plurality of glass plates; a device formation step of forming an electronic device including a resin layer on the glass plate; and a peeling step of peeling the glass plate from the resin layer of the electronic device by heating the interface between the resin layer of the electronic device and the glass plate, wherein the plurality of glass plates have a first main surface on which the resin layer is formed and a second main surface located opposite to the first main surface, and the standard deviation of the transmittance of the plurality of glass plates at wavelengths of 308 nm to 355 nm is 3.0 or less.

[0012] As described above, by setting the standard deviation of transmittance at wavelengths of 308 nm to 355 nm for a plurality of glass plates to 3.0 or less, it becomes easier to uniformly heat the interfaces between the glass plates and the resin layer during the peeling process. This makes it possible to prevent the resin layer from remaining on the glass plates when peeling the glass plates from the resin layer. This also makes it less likely that wrinkles will occur in the resin layer during the peeling process. Note that setting the standard deviation of transmittance at wavelengths of 308 nm to 355 nm to 3.0 or less means that the standard deviation of transmittance at a specific wavelength selected from the range of 308 nm to 355 nm (e.g., wavelengths of 308 nm, 343 nm, or 355 nm) is 3.0 or less, and does not necessarily mean that the standard deviation of transmittance at all wavelengths within the range of 308 nm to 355 nm is 3.0 or less.

[0013] It is preferable that the standard deviation Δt of the thicknesses of the plurality of glass plates is 50 μm or less.

[0014] One of the factors that affect the variation in transmittance of the glass plate group in the wavelength range of 308 nm to 355 nm is the change in plate thickness of each glass plate constituting the glass plate group. In the present invention, by setting the standard deviation Δt of the plate thickness of the glass plate to 50 μm or less, it is possible to reduce the variation in transmittance of the glass plate group in the wavelength range of 308 nm to 355 nm.

[0015] In the present invention, the content of Fe2O3 in the glass plate is preferably 0.001 to 0.05% by mass in terms of oxide.

[0016] Another factor affecting the variation in transmittance of the glass plate group in the wavelength range of 308 nm to 355 nm is the change in the Fe2O3 content of each glass plate constituting the glass plate group. When incorporated into glass, Fe is a component that absorbs light with wavelengths of 430 nm or less and light in a broad wavelength range centered around 1080 nm. Therefore, a change in the Fe2O3 content of the glass plate group changes the transmittance in the wavelength range of 308 nm to 355 nm. In the glass plate group of the present invention, by controlling the Fe2O3 content within the range of 0.001 to 0.05%, it is possible to reduce the variation in transmittance of the glass plate group in the wavelength range of 308 nm to 355 nm.

[0017] In the present invention, the standard deviation of the Fe2O3 content in the glass plates is preferably 0.0009% or less in terms of mass % converted to oxide. By controlling the standard deviation of the Fe2O3 content in the plurality of glass plates to 0.0009% or less in this way, it is possible to reduce the variation in transmittance of the group of glass plates in the wavelength range of 308 nm to 355 nm.

[0018] The thickness of the glass plate is preferably 2.0 mm or less. If the thickness of the glass plate group is too thick, the energy of the UV laser used to peel the resin layer in the peeling step is easily absorbed by the glass plate, making it difficult to peel the resin layer. In the present invention, by setting the thickness of the glass plate to 2.0 mm or less, it becomes easy to peel the glass plate from the resin layer of the electronic device.

[0019] In the preparation step, a rectangular evaluation area having a first side along the sheet drawing direction and a second side along a direction perpendicular to the sheet drawing direction is set on the glass sheet, and the difference in front and back deflection of the evaluation area is preferably −0.8 to 0.8 mm.

[0020] If the difference in front-to-back deflection of the glass plate group is too large, the shape of the glass plate will be uneven, and when the interface between the glass plate and the resin layer is heated with a UV laser to separate them in the peeling process, the laser is likely to be out of focus. As a result, the heating state at the interface between the glass plate and the resin layer is likely to become uneven, and the peelability of the resin layer is reduced. In the present invention, by setting the difference in front-to-back deflection within the above numerical range, the glass plate can be suitably peeled from the resin layer.

[0021] The glass plate is preferably a rectangle having sides of 200 mm or more, which allows for efficient production of electronic devices.

[0022] The linear thermal expansion coefficient of the plurality of glass plates at 30 to 380°C is 30 × 10 -7 / ℃~50×10 -7 / ° C. This can prevent the occurrence of total pitch deviation during the manufacture of electronic devices, and can also prevent cracks in the resin layer formed on the glass plate.

[0023] The thermal shrinkage of the glass plate is preferably 30 ppm or less, which makes it possible to minimize the total pitch deviation (deviation of the TFT pattern) particularly when fabricating an organic EL device using low-temperature polysilicon (LTPS).

[0024] The transmittance of the glass plate at a wavelength of 308 nm is preferably 60% to 85%. By employing the above configuration, it is possible to minimize the laser output when peeling the glass plate from the resin layer of the electronic device in the peeling step using an XeCl excimer laser.

[0025] The transmittance of the glass plate at a wavelength of 343 nm is preferably 83% to 92%. By employing the above configuration, it is possible to minimize the laser output when peeling the glass plate from the resin layer of the electronic device in the peeling step using an Yb-YAG solid state laser.

[0026] The transmittance of the glass plate at a wavelength of 355 nm is preferably 87% to 92%. By employing the above configuration, it is possible to minimize the laser output when peeling the glass plate from the resin layer of the electronic device in the peeling step using an Nd-YAG solid state laser.

[0027] In the present invention, the glass plates constituting the glass plate group are preferably made of glass containing, in mass % calculated as oxides, 50 to 70% SiO2, 10 to 25% Al2O3, 0.1 to 5% B2O3, and 10 to 30% MgO+CaO+SrO+BaO.

[0028] The resin layer formed on the glass plate in the device formation step may contain at least one selected from the group consisting of polyimide, polyamideimide, polyetherimide, and polyesterimide. By employing the above-described configuration, it is possible to fabricate a flexible organic EL device having good device characteristics. [Effects of the Invention]

[0029] According to the present invention, it is possible to make it possible to prevent wrinkles from occurring in the resin layer of the electronic device when peeling off the glass plate from the electronic device. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a flowchart illustrating a method for manufacturing an electronic device. [Figure 2] FIG. 1 is a side view showing a pallet on which glass plates are loaded in a vertical position. [Figure 3] FIG. 1 is a side view showing a pallet on which glass plates are loaded in a horizontal position. [Figure 4] FIG. [Figure 5] FIG. 2 is a front cross-sectional view of a forming furnace. [Figure 6] 6 is a cross-sectional view of the forming furnace taken along the line VI-VI of FIG. 5. [Figure 7]FIG. 2 is a plan view of a glass plate on which an evaluation area is set. [Figure 8] FIG. 1 is a conceptual diagram for explaining a difference in deflection of a glass plate. [Figure 9A] FIG. 10 is a side view showing a device forming step. [Figure 9B] FIG. 10 is a side view showing a device forming step. [Figure 9C] FIG. 10 is a side view showing a device forming step. [Figure 10A] FIG. [Figure 10B] FIG. [Figure 10C] FIG. [Figure 10D] FIG. [Figure 11A] FIG. 2 is a plan view illustrating a method for measuring a thermal shrinkage rate. [Figure 11B] FIG. 2 is a plan view illustrating a method for measuring a thermal shrinkage rate. [Figure 11C] FIG. 2 is a plan view illustrating a method for measuring a thermal shrinkage rate. DETAILED DESCRIPTION OF THE INVENTION

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figures 1 to 10 show an embodiment of a method for manufacturing an electronic device according to the present invention and a group of glass plates used in this method.

[0032] 1, this method includes a preparation step S1 of preparing a glass plate group including a plurality of glass plates, a device formation step S2 of forming an electronic device including a resin layer (resin substrate) on the glass plate as a carrier glass, and a separation step S3 of heating the interface between the resin layer of the electronic device and the glass plate to separate the glass plate from the resin layer. Hereinafter, an example of manufacturing an organic EL device (organic EL display) will be described as the electronic device.

[0033] 2 and 3 show examples of a group of glass plates prepared in the preparation step S1.

[0034] 2, the glass plate group Gg includes a plurality of glass plates Gs stacked in a vertical position (preferably at an angle of 45° to 80° with respect to the horizontal, and more preferably at an angle of 60° to 75° with respect to the horizontal) on a single vertically placed pallet 1. The pallet 1 is equipped with a bottom support portion 1a that supports the bottom surface of the glass plate group Gg, which is made up of a stack of vertically placed glass plates Gs, and a back support portion 1b that supports the back surface of the glass plate group Gg.

[0035] 3, the glass plate group Gg may include a plurality of glass plates Gs stacked in a horizontal position (preferably 0° (horizontal position) to 30°, more preferably 0° to 15°) on a single horizontal placement pallet 2. The pallet 2 is provided with a bottom support portion 2a that supports the bottom of the glass plate group Gg, which is made up of a stack of glass plates Gs in a horizontal position.

[0036] In the glass plate group Gg, it is preferable to sandwich protective sheets such as paper (insertion paper) or foam resin sheets between the glass plates Gs. The number of glass plates Gs included in the glass plate group Gg can be, for example, 50 to 500.

[0037] Here, a method for measuring the transmittance and its standard deviation of the glass plate group Gg will be described. Twenty glass plates Gs are randomly selected from the glass plate group Gg, and samples are cut to a size of 50 mm x 50 mm to prepare samples, and the transmittance of each sample is measured.

[0038] To measure transmittance, the sample is placed in an analytical photometer and fixed-point measurements of transmittance are performed at wavelengths of 308 nm, 343 nm, and 355 nm. In this fixed-point measurement, 300 transmittance measurements are performed at fixed points on the sample, and the average value is taken as the transmittance of the sample. The average value of the transmittances of the 20 samples is taken as the transmittance of the glass plate group Gg, and the standard deviation of the transmittances of the 20 samples is taken as the standard deviation of the transmittance of the glass plate group Gg.

[0039] The standard deviation of the transmittance of the glass plate group Gg at wavelengths of 308 to 355 nm is preferably 3.0 or less, 2.5 or less, 2.2 or less, 1.8 or less, 1.5 or less, 1.3 or less, 1.1 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, particularly preferably 0.4 or less.

[0040] If the standard deviation is too large, it is difficult to uniformly heat the interface between the glass sheet Gs and the resin layer of the electronic device in the peeling step S3, which can result in the resin layer not being peeled cleanly from the glass sheet Gs and the resin layer being prone to wrinkles after peeling from the glass sheet Gs. On the other hand, if the standard deviation is too small, it is necessary to minimize the Fe2O3 contamination in the glass frits. This requires the use of extremely high-purity glass frits, which significantly increases manufacturing costs. In addition, to reduce the standard deviation Δt of the sheet thickness, the sheet drawing speed when forming the glass sheet Gs by the overflow Dandruff method is drastically reduced, significantly reducing productivity. From the viewpoints of the aforementioned manufacturing costs and productivity, it is preferable that the standard deviation of the transmittance of the glass sheet group Gg at wavelengths of 308 to 355 nm is 0.01 or more.

[0041] Next, a method for measuring the standard deviation Δt of the thickness t of the glass plate group Gg will be described. The thickness t of 20 glass plates Gs randomly sampled from the glass plate group Gg is measured. In measuring the thickness t, the thickness t is measured at 20 mm intervals using a micrometer or the like along a direction perpendicular to the sheet drawing direction.

[0042] Thereafter, the average value of the thicknesses t is calculated from the obtained measurement results and is defined as the thickness t of the glass plate Gs. The average value of the thicknesses t of the 20 glass plates Gs is defined as the thickness t of the glass plates Gs of the glass plate group Gg, and the standard deviation of the thicknesses t of the 20 glass plates Gs is defined as the standard deviation of the thicknesses of the glass plate group Gg. The thickness t is preferably 2.0 mm or less, 1.5 mm or less, 1.0 mm or less, 0.7 mm or less, particularly preferably 0.6 mm or less.

[0043] If the plate thickness t is too thick, the energy of the UV laser used in the peeling step S3 is easily absorbed by the glass plate Gs, making it difficult to peel the resin layer of the electronic device from the glass plate. On the other hand, from the viewpoint of preventing warping of the glass plate, the plate thickness t is preferably 0.1 mm or more.

[0044] The standard deviation Δt of the plate thickness of the glass plate group Gg is preferably 50 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 27 μm or less, 25 μm or less, particularly preferably 20 μm or less.

[0045] If the standard deviation Δt of the sheet thickness is too large, the transmittance at wavelengths of 308 nm to 355 nm will vary greatly, making it difficult to uniformly heat the interface between the glass sheet Gs and the resin layer of the electronic device in the peeling step S3. On the other hand, from the viewpoint of productivity, it is preferable that the standard deviation Δt of the sheet thickness is 1 μm or more.

[0046] Next, a method for measuring the standard deviation of the Fe2O3 content of the glass plate group Gg will be described. The Fe2O3 content of 20 glass plates Gs randomly selected from the glass plate group Gg is measured by chemical analysis. Specifically, the glass sample is crushed and dried, then dissolved in an acid solution, and the Fe concentration in the solution is measured using ICP-OES. This is converted to the content in the glass to determine the Fe2O3 content. The standard deviation is calculated from the Fe2O3 content of the 20 glass plates Gs and used as the standard deviation of the Fe2O3 content of the glass plate group Gg. It is preferable that the standard deviation of the Fe2O3 content of the glass plate group Gg is 0.0009% or less, 0.0008% or less, and particularly 0.0007% or less, in terms of mass % oxide.

[0047] If the standard deviation of the Fe2O3 content is too large, the transmittance of the glass plate group Gg at wavelengths of 308 nm to 355 nm will vary greatly, making it difficult to uniformly heat the interface between the glass plate Gs and the resin layer of the electronic device. From the viewpoint of manufacturing costs, the standard deviation Δt of the Fe2O3 content is preferably 0.0001% or more. Details of the components of the glass plate Gs will be described later.

[0048] As shown in Fig. 4, the glass plate Gs manufactured as described above is configured in a quadrilateral shape having a first side Ga and a second side Gb. Each side Ga, Gb is preferably 200 mm or more, 500 mm or more, 800 mm or more, particularly preferably 1000 mm or more.

[0049] If the length dimensions of the sides Ga and Gb of the glass plate Gs are too small, an extremely large number of glass plates Gs will be required to increase the production volume of electronic devices, resulting in a decrease in productivity. Furthermore, if glass plates Gs with shapes other than rectangular are used, the loss during cutting into the product shape increases, resulting in a decrease in productivity. On the other hand, the upper limit of the length of each side Ga and Gb can be set to, for example, 3000 mm.

[0050] The glass plate Gs has a first main surface GS1 on which an electronic device is formed, and a second main surface GS2 located on the opposite side of the first main surface GS1.

[0051] A method for producing the glass plate Gs will be described below. The glass plate Gs can be produced by charging glass raw materials prepared to have a desired glass composition into a continuous melting furnace, heating and melting the glass raw materials, degassing the glass raw materials, and then supplying the glass raw materials to a forming furnace, where the molten glass is formed into a plate shape and slowly cooled.

[0052] From the viewpoint of producing a glass sheet Gs with the required good forming quality, it is preferable that the glass sheet Gs be formed using an overflow downdraw method. Figures 5 and 6 show a forming furnace capable of carrying out the overflow downdraw method.

[0053] 5 and 6, the forming furnace 3 has a forming body 4 and furnace walls 5a to 5f that cover the forming body 4. As shown in Fig. 6, the forming body 4 has an overflow groove 4a through which the molten glass Gm overflows, side walls 4b and 4c that guide the molten glass Gm downward, and a lower end 4d that fuses the molten glass Gm.

[0054] The furnace walls 5a to 5f are preferably made by cutting a single piece of refractory material. Although it is possible to make the furnace walls 5a to 5f from refractory material made of joining members (members made by joining small refractory blocks with mortar or the like), this method has the problem of cracks occurring at the joining points of the joining members themselves.

[0055] If cracks occur in the furnace walls 5a to 5f, outside air enters the forming furnace 3 through the cracks, causing a local decrease in the temperature of the molten glass Gm. As a result, the thickness of the glass ribbon Gr changes in the area where the temperature decrease of the molten glass Gm occurs, and this increases the variation in the thickness t of the glass sheet Gs.

[0056] Furthermore, the molten glass Gm formed by the forming body 4 is likely to bend due to changes in the sheet thickness t, resulting in a large difference in the deflection between the front and back of the glass sheet Gs. In this embodiment, by using a single refractory material for the furnace walls 5a to 5f of the forming furnace 3, it is possible to produce a glass sheet Gs with small variations in the sheet thickness t and small differences in the deflection between the front and back.

[0057] In the overflow downdraw method, first, the molten glass Gm is made to overflow from both sides of the overflow groove 4a of the forming body 4. Then, the molten glass Gm flowing down along the side wall portions 4b and 4c is fused and integrated at the lower end portion 4d of the forming body 4. As a result, the molten glass Gm is formed into a plate-shaped glass ribbon Gr.

[0058] Thereafter, the glass ribbon Gr is sandwiched between rollers and stretched in the width direction, while being stretched downward (drawn) to obtain the desired width and thickness of the glass ribbon Gr. In Fig. 5 and Fig. 6, the drawing direction of the glass ribbon Gr is indicated by the symbol X.

[0059] Thereafter, the glass ribbon Gr undergoes an annealing step, a cooling step, and a cutting step, and a rectangular glass plate Gs is produced from the glass ribbon Gr.

[0060] In the case of the above-mentioned overflow downdraw method, the outer surface of the molten glass Gm, which is to become the surface of the glass sheet Gs, is formed in a free surface state without contacting the forming body 4. As a result, the glass sheet Gs produced by the overflow downdraw method has better surface quality than other forming methods such as the float method, slot downdraw method, and redraw method.

[0061] The difference in front and back deflection of the glass plate Gs produced as described above is preferably −0.8 to 0.8 mm, −0.7 to 0.7 mm, −0.6 to 0.6 mm, particularly preferably −0.5 to 0.5 mm. The difference in front and back deflection of the glass plate Gs is measured as follows.

[0062] First, as shown in Fig. 7, a rectangular evaluation area EA having a first side EAa along the drawing direction X and a second side EAb along the direction Y perpendicular to the drawing direction is cut out from the glass plate Gs. Each side EAa, EAb of the rectangular evaluation area EA is set to 250 to 500 mm.

[0063] Next, as shown in FIG. 8, the curvature W1 of the glass plate piece Gp formed by cutting out the evaluation area EA is measured when the first main surface GS1 of the glass plate piece Gp is ​​placed on the upper side and both ends of the second edge EAb along the direction Y perpendicular to the sheet drawing direction are supported. The curvature W2 of the glass plate piece Gp is ​​measured in the same manner with the second main surface GS2 of the glass plate piece Gp placed on the upper side. The difference (W1 - W2) is calculated as the front-to-back deflection difference. The support interval L is calculated by subtracting 20 mm from the length of the second edge EAb. The front-to-back deflection difference is calculated by (W1 - W2) x (350 / L) so that the support interval L is 350 mm. The front-to-back deflection difference is measured for each evaluation area EA. A front-to-back deflection difference of -0.8 to 0.8 mm means that the front-to-back deflection difference for all evaluation areas EA is -0.8 to 0.8 mm.

[0064] If the difference in deflection between the front and back surfaces is too large, the shape of the glass plate Gs will be uneven, which will likely cause laser misfocusing when the interface between the glass plate Gs and the resin layer of the electronic device is heated with a UV laser to separate them in the peeling step S3. As a result, the heating state at the interface between the glass plate Gs and the resin layer of the electronic device will likely become uneven, reducing the peelability of the resin layer of the electronic device.

[0065] The linear thermal expansion coefficient of the glass plate Gs at 30 to 380°C is 30 × 10 -7 / ℃~50×10 -7 / ℃, 33×10 -7 / ℃~47×10 -7 / ℃, especially 35×10 -7 / ℃~45×10 -7 / °C is preferred.

[0066] If the thermal expansion coefficient is too large, total pitch deviation (misalignment of the TFT pattern) is likely to occur, especially when fabricating organic EL devices using low-temperature polysilicon (LTPS).On the other hand, if the thermal expansion coefficient is too small, the difference in thermal expansion coefficient with the resin layer becomes large, making the resin layer more likely to crack.

[0067] The glass plate Gs preferably has a transmittance in the thickness direction at a wavelength of 308 nm of 60% or more, 63% or more, 67% or more, particularly 70% or more. The glass plate Gs preferably has a transmittance in the thickness direction at a wavelength of 343 nm of 83% or more, 84% or more, 85% or more, particularly 87% or more. The glass plate Gs preferably has a transmittance in the thickness direction at a wavelength of 355 nm of 87% or more, 88% or more, particularly 89% or more. If the transmittance is too low, the energy of the UV laser used to peel the resin layer is more likely to be absorbed by the glass plate Gs, making it difficult to peel the resin layer.

[0068] The glass plate Gs preferably contains, as glass constituents, in mass % calculated as oxides, 50 to 70% SiO2, 10 to 25% Al2O3, 0.1 to 5% B2O3, 15 to 30% MgO+CaO+SrO+BaO, and 0.001 to 0.05% Fe2O3.

[0069] The reasons for limiting the content of each component as described above are as follows.

[0070] SiO2 is the main component that forms the glass skeleton structure. The SiO2 content is 50 to 70%, preferably 52 to 68%, 55 to 65%, and particularly preferably 57 to 63%. If the SiO2 content is too high, the melting property decreases and the manufacturing cost increases. On the other hand, if the SiO2 content is too low, the chemical durability decreases and the glass component elutes into the resin when the resin layer is fired.

[0071] Al2O3 is the main component that forms the glass skeleton structure and also enhances the stability of the glass. The Al2O3 content is 10 to 25%, preferably 12 to 23%, and particularly preferably 15 to 22%. If the Al2O3 content is too high, the melting property decreases and the manufacturing cost increases. On the other hand, if the Al2O3 content is too low, the stability of the glass decreases, devitrified crystals such as mullite and anorthite tend to precipitate, and defects in the glass increase.

[0072] Like SiO2, B2O3 is a component that forms the framework of the glass network structure. However, unlike SiO2, it does not increase the melting temperature of the glass; rather, it acts to lower the melting temperature. The B2O3 content is 0.1 to 5%, preferably 0.2 to 3%, 0.4 to 2%, and particularly preferably 0.5 to 1%. If the B2O3 content is too high, the Young's modulus of the glass decreases, resulting in a large difference in deflection between the front and back surfaces. On the other hand, if the B2O3 content is too low, the melting property decreases and the manufacturing cost increases.

[0073] MgO, CaO, SrO, and BaO are components that enhance the meltability of glass. The content of MgO+CaO+SrO+BaO is 10 to 30%, preferably 13 to 28%, 15 to 25%, and particularly preferably 17 to 22%. If the content of MgO+CaO+SrO+BaO is too high, the chemical durability of the glass will be significantly reduced, and the glass components will leach into the resin layer during firing of the resin layer of the electronic device in the device formation step S2, significantly changing the properties of the resin layer. On the other hand, if the content of MgO+CaO+SrO+BaO is too low, the meltability will decrease and the manufacturing cost will increase.

[0074] Fe2O3 is a component that functions as a fining agent. The Fe2O3 content is preferably 0.001 to 0.05%, 0.003 to 0.04%, 0.005 to 0.03%, and particularly preferably 0.007 to 0.02%. If the Fe2O3 content is too high, the transmittance of the glass sheet group Gg at wavelengths of 308 nm to 355 nm will vary greatly, making it difficult to achieve a uniform heating state at the interface between the glass sheet Gs and the resin layer of the electronic device in the peeling step S3. On the other hand, Fe is not intentionally added, but is inevitably mixed in as an impurity from glass raw materials, glass cullet, equipment, etc. used in the production of glass sheets during the manufacturing process. Here, glass cullet refers to defective glass generated during the glass manufacturing process and recycled glass recovered from home appliances, etc.

[0075] As a method for making the standard deviation of the Fe2O3 content 0.0009% or less, for example, the amount of glass cullet used can be reduced, or glass cullet can be eliminated altogether. Alternatively, high-purity glass raw materials with few impurities can be used.

[0076] A predetermined number of glass plates Gs manufactured as described above are loaded onto pallets 1 and 2 to prepare a group of glass plates Gg to be used in the device forming step S2.

[0077] Next, the device formation step S2 will be described with reference to FIG.

[0078] As shown in FIG. 9A, in the device forming step S2, first, a resin layer 6 that will become a substrate for an organic EL element is formed on the first main surface GS1 of the glass plate Gs (resin layer forming step).

[0079] The resin layer 6 preferably contains at least one selected from the group consisting of polyimide, polyamideimide, polyetherimide, and polyesterimide. By containing these components, an organic EL device having good device characteristics can be produced.

[0080] When the resin layer 6 in this embodiment is a polyimide layer, the resin layer 6 can be formed by applying a polyimide solution (a solution in which polyimide is melted or dissolved in an organic solvent), which is a precursor of polyimide, to a glass plate Gs and then heating and drying. A spin coater can be used as an application method, but this method is not limited to this. The applied solution is then dried, for example, by vacuum drying. The polyimide layer can also be formed by thermal imidization of polyamic acid. The thickness of the polyimide layer thus formed is, for example, 5 to 50 μm.

[0081] Next, as shown in FIG. 9B, a TFT layer 7 (TFT: Thin Film Transistor) is formed on the resin layer 6 (TFT layer forming step).

[0082] The TFT layer 7 includes a TFT array circuit that realizes an active matrix. Materials for the semiconductor layers that make up the TFT elements include, for example, crystalline silicon, amorphous silicon, oxide semiconductor, and low-temperature polysilicon (LTPS). The thickness of the TFT layer 7 is, for example, 4 μm, but is not limited to this dimension.

[0083] 9C, an insulating layer 8 is formed on the TFT layer 7 (insulating layer forming step). The insulating layer 8 is intended to flatten steps on the upper surface of the TFT layer 7. Like the resin layer 6, the insulating layer 8 is made of a resin layer such as polyimide.

[0084] Thereafter, an organic EL layer 9 is formed on the insulating layer 8 (organic EL layer forming step). The organic EL layer 9 includes an array of OLED elements that can be driven independently. The organic EL layer 9 has a known structure in which, in addition to an organic light-emitting layer, a hole transport layer, an electron transport layer, a hole injection layer, an electron injection layer, and the like are stacked. The thickness of the organic EL layer 9 is, for example, 1 μm, but is not limited to this dimension.

[0085] In the device formation step S2, known components such as an electrode layer, a sealing layer, etc. are laminated in addition to the TFT layer 7, the insulating layer 8, and the organic EL layer 9. In this device formation step S2, a laminate LM is formed in which an organic EL device D as an electronic device and a glass plate Gs are laminated.

[0086] Next, the peeling step S3 will be described with reference to FIGS. 10A to 10D.

[0087] 10A, in the peeling step S3, first, a protective sheet 10 is attached to the organic EL device D. The protective sheet 10 may have adhesive properties or gas barrier properties. The thickness of the protective sheet 10 is, for example, 50 to 300 μm.

[0088] 10B, the laminate LM is inverted and placed on the surface plate 11. In this case, the laminate LM is placed on the surface plate 11 so that the protective sheet 10 is interposed between the laminate LM and the surface plate 11. As a result, the laminate LM is placed on the surface plate 11 so that the glass plate Gs is located on top.

[0089] Thereafter, a laser LS, such as a UV laser, is irradiated onto the glass plate Gs using a laser irradiation device 12 shown in FIG. 10C. The laser LS is configured, for example, in a line shape, and is scanned in a predetermined direction while being irradiated onto the interface between the resin layer 6 and the first main surface GS1 of the glass plate Gs. The wavelength of the laser LS is selected so that it is absorbed and decomposed by the resin layer 6 as little as possible as possible. The wavelength of the laser LS is, for example, 308 nm, 355 nm, or 343 nm. As shown in FIG. 10D, the interface is heated by the laser LS, causing the glass plate Gs to peel off from the resin layer 6 of the organic EL device D and be removed from the organic EL device D.

[0090] According to the manufacturing method of the electronic device (organic EL device D) of this embodiment described above, by setting the standard deviation of the transmittance of the glass plates Gs included in the glass plate group Gg at wavelengths of 308 nm to 355 nm to 3.0 or less, it becomes easier to uniformly heat the interface between the first main surface GS1 of the glass plate Gs and the resin layer 6 of the electronic device in the peeling step S3. As a result, in the peeling step S3, the resin layer 6 can be suitably peeled off from the electronic device without remaining on the glass plate Gs. As a result, wrinkles are less likely to occur in the resin layer 6 in the peeling step S3.

[0091] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention. [Example]

[0092] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0093] (1) Glass composition and properties Table 1 below shows an example of the composition of the glass constituting the glass plate group used in the present invention (Sample No. 1) and the measurement results of the properties (thermal expansion coefficient, transmittance).

[0094] First, a glass batch was prepared by weighing and mixing various glass raw materials, including natural and chemical raw materials, to obtain the glass composition shown in Table 1. Next, this glass batch was placed in a platinum-rhodium alloy crucible and melted at 1600°C for 24 hours in an indirect heating electric furnace. The molten glass was then poured onto a carbon plate and formed into a plate. The thermal expansion coefficient of this glass sample was measured.

[0095] The average thermal expansion coefficient was measured in the temperature range of 30 to 380° C. using a dilatometer in accordance with JIS R3102. [Table 1]

[0096] (2) Preparation of glass plates and various measurements For Examples 1 to 11, a batch prepared by blending only low-iron raw materials to obtain the composition of Sample No. 1 was melted in a glass melting furnace, and a glass ribbon was formed by the overflow Dandruff method using a forming furnace made of a single refractory material. The glass ribbon was then cut and processed to obtain a rectangular glass plate measuring 1500 mm × 1850 mm.

[0097] At this time, the glass plates were cut and harvested so that the short sides (1500 mm) of the glass plates were in the sheet drawing direction and the long sides (1850 mm) of the glass plates were in the width direction perpendicular to the sheet drawing direction. After fixing the glass production conditions, 200 glass plates were harvested and loaded in a vertical position on a vertical pallet to produce a group of glass plates of Example 1.

[0098] Furthermore, during forming by the overflow downdraw method, the speed of the tension roller, the speed of the cooling roller, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the glass, the sheet drawing speed, the rotation speed of the stirring stirrer, etc. were changed to adjust the thickness t of the glass sheet, the difference in deflection between the front and back surfaces, and the thermal shrinkage rate, thereby producing the glass sheet groups of Examples 2 to 11.

[0099] Next, in Comparative Example 1, a batch was prepared by blending glass cullet with raw materials containing Fe as an impurity so as to obtain the composition of Sample No. 1, and the batch was melted in a glass melting furnace. A forming furnace made of a refractory material for the joining members was used to produce a group of glass plates for Comparative Example 1 in the same manner as in Example 1.

[0100] Here, the thickness t, the difference in front and back deflection, and the thermal shrinkage of the examples and comparative examples were measured by extracting one glass substrate from a group of glass substrates.

[0101] The thickness t of the glass plate in each example was determined by cutting a glass sample from a single glass plate, measuring 50 mm in the drawing direction and 1,850 mm in the width direction perpendicular to the drawing direction, measuring the thickness t at 93 locations at 20 mm intervals on a randomly selected cross section in the thickness direction, and calculating the average value.

[0102] To measure the difference in front and back deflection, four evaluation areas were set on a single glass plate. Each evaluation area was a rectangle measuring 370 mm in the width direction perpendicular to the drawing direction and 470 mm in the drawing direction. The difference in front and back deflection was measured using glass pieces obtained by cutting these evaluation areas.

[0103] The thermal shrinkage was measured by cutting a 30 mm × 160 mm sample from a glass plate as follows: As shown in Fig. 11A, two linear marks M1 and M2 were written at a predetermined distance on a predetermined portion of the glass plate sample Gp, and then, as shown in Fig. 11B, the sample Gp was cut in a direction perpendicular to the marks M1 and M2 to obtain two glass plate pieces Gpa and Gpb.

[0104] Then, only one of the glass plates Gpa was heated from room temperature to 500°C at a rate of 10°C / min, held at 500°C for 1 hour, and then cooled to room temperature at a rate of 10°C / min.

[0105] Then, as shown in Figure 11C, the heat-treated glass plate Gpa and the non-heat-treated glass plate Gpb were placed side by side and fixed with adhesive tape T, and the deviation between the marks M1 and M2 on the glass plate Gpa was measured, and the thermal shrinkage rate C was calculated based on the following formula (1).

[0106] C(ppm)=(Δl1(μm)+Δl2(μm)) / l0(m)...(1)

[0107] In the above formula (1), l0 is the distance between the marks M1 and M2 on the glass plate Gp, Δl t is the distance between the mark M1 of the glass plate piece Gpa and the mark M1 of the glass plate piece Gpb, and Δl2 is the distance between the mark M2 of the glass plate piece Gpa and the mark M2 of the glass plate piece Gpb.

[0108] To measure the transmittance, a glass plate was cut to a size of 50 mm x 50 mm to prepare a sample, and the 50 mm x 50 mm surface was placed on an analytical photometer (Shimadzu Corporation UV-3100PC) as the measurement surface, and the transmittance was measured at wavelengths of 308 nm, 343 nm, and 355 nm.

[0109] (3) Fabrication and evaluation of organic EL devices Twenty glass plates were randomly selected from the glass plate groups of Examples 1 to 11 and Comparative Example 1, and the selected glass plates were cut in half to a size of 1500 mm × 925 mm to prepare sample glass plates. Organic EL devices were fabricated using these sample glass plates.

[0110] The organic EL device was fabricated as follows. First, a polyimide solution (a solution of polyimide melted or dissolved in an organic solvent) was applied to one side of a sample glass plate, and a colorless, transparent polyimide layer was formed as a resin layer by heating and drying at 450°C. Next, a TFT layer and an organic EL layer were formed on the polyimide layer. Furthermore, a protective sheet made of polyethylene terephthalate was attached on the organic EL layer.

[0111] Next, the organic EL device was turned upside down along with the glass plate and placed on a surface plate. The glass plate was then irradiated with a line-shaped UV laser (wavelengths of 308 nm, 343 nm, and 355 nm) to peel the glass plate and the polyimide layer. The glass plate was then lifted off, and the remaining polyimide on the glass plate was visually confirmed, along with the presence or absence of wrinkles in the polyimide layer, to evaluate the device.

[0112] The meanings of the evaluation of the remaining polyimide layer on the glass substrate and the wrinkles in the polyimide layer shown in Tables 2 and 3 are as follows. ⊚: Indicates that the polyimide layer remained on the glass substrate and no wrinkles occurred in the polyimide layer in any of the 20 organic EL devices, and that the devices were excellent. ◯: indicates that wrinkles occurred in the remaining polyimide layer on the glass substrate only in a few of the 20 organic EL devices, and the devices were good. ×: indicates that in most of the 20 organic EL devices, the polyimide layer remained on the glass substrate or wrinkles occurred in the polyimide layer, and the devices were unsuitable.

[0113] The measurement results and evaluation results for the glass plates of Examples 1 to 11 and Comparative Example 1 are shown in Tables 2 and 3 below. [Table 2] [Table 3]

[0114] As is clear from the results in Tables 2 and 3, in the comparative examples, the standard deviation of the transmittance exceeded 3.0. As a result, there were many remaining polyimide layers on the glass substrate and wrinkles in the polyimide layer occurred frequently, and the evaluation was ×. In Examples 1 to 11, the standard deviation of the transmittance was 3.0 or less, the remaining of the polyimide layer on the glass substrate and the like were reduced, and the evaluation was ◎ or 〇. Further, in Examples 1, 2, 4, 7, and 11, the standard deviation of the transmittance was 0.4 or less and the front-back deflection difference was -0.5 to 0.5 mm, and there was no occurrence of the remaining of the polyimide layer on the glass substrate and the like, and the evaluation was ◎.

Explanation of Signs

[0115] 6 Resin layer D Electronic device EA Evaluation region Ga First side of glass plate Gb Second side of glass plate Gg Group of glass plates Gs Glass plate GS1 First main surface of glass plate GS2 Second main surface of glass plate S1 Preparation process S2 Device formation process S3 Peeling process

Claims

1. a preparation step of preparing a glass plate group including a plurality of glass plates; a device forming step of forming an electronic device including a resin layer on the glass plate; a peeling step of peeling the glass plate from the resin layer of the electronic device by heating an interface between the resin layer of the electronic device and the glass plate, The plurality of glass plates are 50 to 500 glass plates, The plurality of glass plates each have a first main surface on which the resin layer is formed and a second main surface located opposite to the first main surface, the standard deviation of transmittance at wavelengths of 308 nm, 343 nm, and 355 nm for the plurality of glass plates is 0.8 or less; The standard deviation Δt of the plate thicknesses of the plurality of glass plates is 20 μm or less, The content of Fe 2 O 3 in the glass plate is 0.001 to 0.05% by mass in terms of oxide, The method for producing an electronic device according to claim 1, wherein the standard deviation of the Fe 2 O 3 content in the plurality of glass plates is 0.0009% or less in terms of mass % converted to oxide.

2. The method for manufacturing an electronic device according to claim 1 , wherein the glass plate has a thickness t of 2.0 mm or less.

3. In the preparation step, a rectangular evaluation area having a first side along a sheet drawing direction and a second side along a direction perpendicular to the sheet drawing direction is set on the glass sheet, 3. The method for manufacturing an electronic device according to claim 1, wherein the difference in deflection between the front and back surfaces of the evaluation area is −0.8 to 0.8 mm.

4. The method for manufacturing an electronic device according to claim 1 , wherein the glass plate is a rectangle having sides of 200 mm or more.

5. The linear thermal expansion coefficient of the glass plate at 30 to 380°C is 30 x 10 －７ / ℃~50×10 －７ The method for producing an electronic device according to claim 1 , wherein the temperature is 100° C. / ° C.

6. The method for manufacturing an electronic device according to claim 1 , wherein the glass plate has a thermal shrinkage rate of 30 ppm or less.

7. 7. The method for manufacturing an electronic device according to claim 1, wherein the transmittance of the glass plate at a wavelength of 308 nm is 60 to 85%.

8. The method for producing an electronic device according to any one of claims 1 to 7, wherein the transmittance of the glass plate at a wavelength of 343 nm is 83 to 92%.

9. 9. The method for producing an electronic device according to claim 1, wherein the glass plate has a transmittance of 87 to 92% at a wavelength of 355 nm.

10. The glass plate contains, in mass % in terms of oxide, SiO ２ 50-70%, Al ２ O ３ 10-25%, B ２ O ３ 10. The method for manufacturing an electronic device according to claim 1, wherein the glass contains 0.1 to 5% of MgO, 0.1 to 5% of CaO, 0.1 to 5% of SrO, and 10 to 30% of MgO, CaO, SrO, and BaO.

11. The method for producing an electronic device according to claim 1 , wherein the resin layer contains at least one selected from the group consisting of polyimide, polyamideimide, polyetherimide, and polyesterimide.

12. A glass plate group including a plurality of glass plates, The plurality of glass plates are 50 to 500 glass plates, the glass plate has a first main surface on which a resin layer of an electronic device is formed and a second main surface located opposite to the first main surface, the standard deviation of transmittance at wavelengths of 308 nm, 343 nm, and 355 nm for the plurality of glass plates is 0.8 or less; The standard deviation Δt of the plate thicknesses of the plurality of glass plates is 20 μm or less, The content of Fe 2 O 3 in the glass plate is 0.001 to 0.05% by mass in terms of oxide, The group of glass plates, wherein a standard deviation of the Fe 2 O 3 content in the plurality of glass plates is 0.0009% or less in mass % calculated as oxide.

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