JP2012138547A - Manufacturing method of flexible electronic device, multilayer substrate with resin layer, and flexible electronic device manufacturing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a flexible electronic device to suppress degassing from an adhesion layer in a vacuum process, a multilayer substrate with a resin layer for manufacturing a flexible electronic device with little degassing, and a flexible electronic device manufacturing member.SOLUTION: The manufacturing method of a flexible electronic device comprises processes of: releasing at least a part of a volatile component of an adhesion layer 20 by performing a heat treatment after bonding a flexible substrate 22 via the adhesion layer 20 to a support substrate 30 excellent in dimensional stability; and suppressing degassing from the adhesion layer 20 by providing a cover resin layer 24 to cover an exposed part of the adhesion layer 20.

Description

  The present invention relates to a method for manufacturing a flexible electronic device with a low yield and a high yield in a vacuum process, and a laminated substrate with a resin layer used for manufacturing the flexible electronic device and a flexible electronic device. The present invention relates to a manufacturing member.

  As electronic devices have been reduced in size and weight, so-called flexible electronic devices in which electronic elements are formed on a flexible substrate have been developed in recent years. In addition to miniaturization and weight reduction, flexible electronic devices have many advantages such as improved impact resistance and low cost of the substrate. In particular, the display device uses a thin film transistor (TFT) as an electronic element. Flexible displays are expected to be applied to next-generation portable terminals, flexible TVs, digital signage, and the like, and research and development are being conducted energetically.

As a process for forming an electronic element such as a TFT, generally, there are a heat treatment process such as formation of an insulating film by chemical vapor deposition (CVD) and annealing, and a wet process using various chemical solutions such as etching and development. In general, a vacuum process is frequently used in the manufacture of electronic devices regardless of the flexibility or inflexibility of the substrate. This is because film thickness and film quality can be easily controlled as compared with liquid phase processes such as coating and printing, and by using together with the photolithography technique, a fine electronic element can be manufactured with high accuracy.
When a flexible substrate is used for an electronic element such as a TFT, a change in shape due to expansion / contraction, expansion, deflection, or the like becomes a problem. In particular, in the case of manufacturing a high-definition flexible display, there is a problem that patterning accuracy required for manufacturing an electronic device cannot be obtained if the shape of the flexible substrate changes between processes. For this reason, when a flexible electronic device is manufactured by a vacuum process using a flexible substrate such as various films, unlike a non-flexible substrate such as glass, the substrate can be stretched or changed in shape. Various devices are required for patterning with high accuracy.

  Therefore, in order to avoid such a problem, an electronic element is formed on a substrate with excellent dimensional stability via a release layer, and then the electronic element is primarily transferred to a temporary transfer substrate, and further to a flexible substrate. By secondary transfer, the method of indirectly forming the electronic element on the flexible substrate, or by sticking the flexible substrate to a substrate with excellent dimensional stability and suppressing the dimensional change A method of directly forming on a flexible substrate has been proposed.

  For example, in Patent Document 1, a thin film device layer is formed on a base substrate via a first separation layer, a second separation layer is formed on the thin film device layer, and a first transfer substrate is formed on the second separation layer. Join. Then, the thin film device layer is peeled off from the original substrate with the first separation layer as a boundary, and then the second transfer substrate is bonded to the lower side of the thin film device layer, and the thin film device layer with the second separation layer as the boundary. The first transfer substrate is peeled off to transfer the thin film device layer to the second transfer substrate. In Patent Document 1, a first transfer substrate that is harder or more rigid than the second transfer substrate is used.

  In order to avoid the problem that the patterning accuracy cannot be obtained, as a method for forming a fine circuit on the flexible substrate with high accuracy, the flexible substrate can be bonded to a reinforcing plate via an organic layer. A method has been proposed in which the dimensional accuracy of the flexible substrate is maintained, patterning is performed directly on the flexible substrate, and then the flexible substrate is peeled from the reinforcing plate (see Patent Document 2).

JP 2001-189460 A International Publication No. 03/009657 Pamphlet

However, in the method of Patent Document 1 or the like that transfers to a flexible substrate, when peeling a peeling layer provided between the electronic element and the substrate, the electronic element is easily destroyed and the yield tends to be low.
In particular, in a high-definition, large-area flexible electronic device, it is not easy to transfer without destroying an electronic element, and it is difficult to manufacture with a high yield, and improvement of the transfer method is a major issue. .

  In addition, in the case of attaching a flexible substrate and maintaining dimensional accuracy as in the above-mentioned Patent Document 2 (attachment method), when forming an electronic element by a vacuum process, it is included in the organic layer and the adhesive layer. Organic matter and moisture are degassed. For this reason, especially when semiconductor materials that are greatly affected by the atmosphere during film formation are used for electronic elements, the electrical characteristics of the semiconductor layer that plays a major role in the electronic elements are greatly affected, causing unintended characteristic changes. Therefore, there is a problem directly related to the yield of electronic elements. Thereby, there existed a problem that the yield of a flexible electronic device fell.

  In order to suppress degassing in the vacuum system from the substrate on which the organic layer is formed via the adhesive layer, it is common to release volatile components in the organic matter by performing a heat treatment before transferring the substrate to the vacuum system. Done. However, in the case of an adhesive layer in which two types of substrates are bonded together, even if heat treatment is performed, the volatile components are released only from the end portions of the bonded substrates, and it is difficult to sufficiently remove them. To remove volatile components, heat treatment can be performed at a higher temperature or for a long time, but there are limitations from the viewpoint of the heat resistance temperature of the flexible substrate and manufacturing suitability, both of which are realistic. Is difficult.

The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to achieve the following object.
That is, the first object of the present invention is to form an electronic device directly on a flexible substrate bonded via an adhesive layer on a support substrate having excellent dimensional stability by a vacuum process, and then dimensionally stabilize. In a method of manufacturing a flexible electronic device by peeling a flexible substrate from a support substrate having excellent properties, fine gas is formed on the resin layer on the flexible substrate while suppressing degassing from the adhesive layer in a vacuum process. Another object of the present invention is to provide a flexible electronic device manufacturing method and a flexible electronic device manufacturing member capable of manufacturing an electronic device in which an electronic element having a simple circuit is formed with high accuracy with a high yield.
In addition, the second object of the present invention is that there is little degassing from the adhesive layer in the step of forming the electronic element by a vacuum process, and the electronic element can be formed on the flexible substrate with high accuracy. An object of the present invention is to provide a laminated substrate with a resin layer for manufacturing flexible electronic devices with a good production yield.

As a result of diligent research on a method for manufacturing an electronic device in which electronic elements are accurately formed on a flexible substrate with high yield, the present inventors bonded the flexible substrate to a support substrate having excellent dimensional stability. After that, heat treatment is performed to release at least a part of the volatile components of the adhesive layer, and by covering the exposed part of the adhesive layer with a resin, it has been found that degassing from the adhesive layer can be reduced. This has led to the present invention.
That is, specific means for solving the above-described problems are as follows.

  The method for manufacturing a flexible electronic device of the present invention includes a step of laminating a flexible substrate on the surface of a support substrate excellent in dimensional stability via an adhesive layer, and the support substrate on which the flexible substrate is laminated. Heat treatment to release at least a part of the volatile components in the adhesive layer, and a resin layer is formed on the surface of the support substrate so as to cover the flexible substrate and the adhesive layer A second heat treatment step of heat-treating the support substrate on which the resin layer is formed to release at least a part of volatile components in the resin layer, and using a vacuum process on the resin layer. The method includes a step of forming an element and a step of peeling the flexible substrate from the support substrate.

  In this case, the laminating step is performed so that the entire surface of the flexible substrate smaller than the support substrate on the adhesive layer side is mutually overlapped so that the sides of the flexible substrate and the support substrate do not overlap each other. The step is preferably a step of adhering to the surface of the support substrate by shifting the sides.

  The laminating step includes a step of adhering a second flexible substrate on the surface of the support substrate via an adhesive layer, and an outer edge of the second flexible substrate is removed together with the adhesive layer. Disposing the flexible substrate smaller than the support substrate on the surface of the support substrate so that the sides of the flexible substrate and the support substrate do not overlap each other. It is preferable to have.

The resin layer is preferably formed so as to cover an exposed portion of the adhesive layer, the surface of the flexible substrate, and a part of the surface of the support substrate.
Moreover, it is preferable to have the process of wash | cleaning the said flexible substrate and the said support substrate which were laminated | stacked through the said contact bonding layer before the said 1st heat processing process.

  Further, prior to the step of forming the electronic element, the method further includes a step of providing a sealing layer on the resin layer, and the step of forming the electronic element includes the step of forming the electronic element on the sealing layer. It is preferable to form.

  The sealing layer is formed using, for example, a CVD method or a sol-gel method.

  Moreover, it is preferable to have the 3rd heat processing process heat-processed at the temperature below the heat processing temperature in a said 2nd heat processing process after the process of forming the said electronic element.

  The electronic element is preferably a thin film transistor using an oxide semiconductor as an active layer.

The laminated substrate with a resin layer of the present invention has a support substrate excellent in dimensional stability, and is smaller than the support substrate on the surface of the support substrate with an adhesive layer interposed therebetween, and the support substrate and the side of each other are A flexible substrate that is laminated with the sides shifted so as not to overlap, and a resin layer provided on the surface of the support substrate so as to cover the flexible substrate and the adhesive layer The adhesive layer and the resin layer are formed by degassing at least a part of volatile components in them, and the total pressure at a substrate temperature of 100 ° C. obtained by temperature-programmed desorption gas analysis is a substrate temperature of 50 ° C. It is characterized by being 100 times or less of the total pressure at.
In this case, it is preferable that a sealing layer is provided on the resin layer.

  The flexible electronic device manufacturing member of the present invention is characterized in that an electronic element is formed on the above-mentioned multilayer substrate with a resin layer of the present invention.

According to the manufacturing method of the present invention, degassing in a vacuum process can be suppressed, and thereby, unintended characteristic changes can be suppressed even when a semiconductor material is used for an electronic element. For this reason, the yield of a flexible electronic device can be improved and a flexible electronic device can be manufactured with a high yield.
Moreover, according to the manufacturing method of the present invention, after forming an electronic element on a resin layer by a vacuum process, a flexible electronic device is manufactured by simply peeling the flexible substrate from a support substrate having excellent dimensional stability. Therefore, destruction of the electronic element is suppressed. In addition, since the flexible substrate is laminated on the support substrate having excellent dimensional stability, an electronic element having a fine circuit on the resin layer on the flexible substrate is formed with high accuracy such as patterning accuracy. be able to. For this reason, a flexible electronic device in which an electronic element having a fine circuit is accurately formed on a resin layer on a flexible substrate can be manufactured with a high yield. Furthermore, since only the flexible substrate is peeled from the support substrate to obtain a flexible electronic device, a flexible electronic device having a high definition and a large area can be manufactured with a high yield.

In addition, by using the multilayer substrate with a resin layer of the present invention, the degassing is less in the vacuum process, and after the electronic element is formed on the resin layer by the vacuum process, the electronic element is released from the support substrate having excellent dimensional stability. A flexible electronic device can be manufactured by simply peeling the formed flexible substrate. In addition, since the flexible substrate is laminated on the support substrate having excellent dimensional stability, an electronic element having a fine circuit on the resin layer on the flexible substrate is formed with high accuracy such as patterning accuracy. be able to. Because of this, it is suitable as a substrate for manufacturing flexible electronic devices.
Moreover, according to the flexible electronic device manufacturing member of this invention, a flexible electronic device can be obtained only by peeling off the flexible substrate in which the electronic element was formed from the support substrate excellent in dimensional stability. Moreover, the electronic element is suitable as a precursor for manufacturing a flexible electronic device because it has high precision such as patterning accuracy and has stable characteristics of the semiconductor material constituting the electronic element.

It is typical sectional drawing which shows the flexible electronic device manufactured with the manufacturing method of the flexible electronic device of the 1st Embodiment of this invention. (A)-(f) is a schematic cross section which shows the manufacturing method of the flexible electronic device of the 1st Embodiment of this invention in order of a process. (A) is a schematic diagram which shows an example of the relationship between the support substrate excellent in dimensional stability, and a flexible substrate, (b) is typical sectional drawing of Fig.3 (a). (A) is typical sectional drawing which shows the other example of the relationship between the support substrate excellent in dimensional stability, and a flexible substrate, (b) is typical sectional drawing of Fig.4 (a). . It is typical sectional drawing which shows the flexible electronic device manufactured with the manufacturing method of the flexible electronic device of the 2nd Embodiment of this invention. (A)-(g) is a schematic diagram which shows the manufacturing method of the flexible electronic device of the 2nd Embodiment of this invention in order of a process. (A) is typical sectional drawing which shows the sample structure in the Example of this invention, (b) is a graph which shows the measurement result of a thermal desorption gas analysis (TDS) of an Example. (A) is typical sectional drawing which shows the sample structure in the comparative example 1 of this invention, (b) is a graph which shows the measurement result of the thermal desorption gas analysis (TDS) of the comparative example 1. FIG. (A) is typical sectional drawing which shows the sample structure in the comparative example 2 of this invention, (b) is a graph which shows the measurement result of the thermal desorption gas analysis (TDS) of the comparative example 2. FIG. (A) is typical sectional drawing which shows the sample structure in the comparative example 3 of this invention, (b) is a graph which shows the measurement result of the temperature-programmed desorption gas analysis (TDS) of the comparative example 2. FIG.

Below, based on the suitable embodiment shown in an accompanying drawing, the manufacturing method of a flexible electronic device concerning the present invention, a layered substrate with a resin layer, and a flexible electronic device are explained in detail.
FIG. 1 is a schematic cross-sectional view illustrating a flexible electronic device manufactured by the method for manufacturing a flexible electronic device according to the first embodiment of the present invention. FIGS. 2 (a) to 2 (f) are diagrams illustrating the first embodiment. It is a schematic cross section which shows the manufacturing method of the flexible electronic device of a form in order of a process.

Hereinafter, a method for manufacturing a flexible electronic device according to the present invention will be described.
In the present embodiment, a method for manufacturing a flexible electronic device using, for example, a thin film transistor (TFT) as an electronic element will be described as an example.
A flexible electronic device 10 manufactured by the method for manufacturing a flexible electronic device shown in FIG. 1 has a thin film transistor 14 (hereinafter also referred to as TFT 14) formed on a surface 12 a of a substrate 12.

  The substrate 12 has a flexible substrate 22 formed on the adhesive layer 20, and the adhesive layer 20 and the flexible substrate 22 other than the back surface of the adhesive layer 20, the surface of the flexible substrate 22, and the adhesive layer 20. The resin layer 24 is formed so as to cover the end portion 23 of the flexible substrate 22. The adhesive layer 20 and the end portion 23 of the flexible substrate 22 include an exposed portion of the adhesive layer 20.

  The TFT 14 is called a bottom gate type top contact. A gate electrode 40 formed on the surface 12 a of the substrate 12 and a gate insulating film 42 are formed so as to cover the gate electrode 40. An active layer 44 is formed on the gate insulating film 42. On the active layer 44, a region that matches the gate electrode 40 is formed, and a source electrode 46a and a drain electrode 46b are formed to face each other with the region interposed therebetween.

The gate electrode 40 is made of, for example, Mo, Mo alloy, or Cr.
The gate insulating film 42 is constituted by, for example, a SiO ₂ film, a SiNx film, a SiON film, an Al ₂ O ₃ film, a HfO ₂ film, a Ga ₂ O ₃ film, or the like, or a laminate of these.
The source electrode 46a and the drain electrode 46b are made of, for example, Mo or Mo alloy.

The active layer 44 functions as a channel layer and is made of, for example, an amorphous oxide semiconductor that can be formed on a plastic film having low heat resistance. The amorphous oxide semiconductor constituting the active layer 44 includes at least one of In, Ga, and Zn. Examples of the amorphous oxide semiconductor constituting the active layer 44 include Indium-Zinc-Oxide (IZO) and InGaZnO ₄ (IGZO) represented by (In _2−x Ga _x ) O _3. (ZnO) _m. These homologous compounds are used. However, 0 ≦ x ≦ 2 and m is a natural number.
In addition, in the TFT 14, an insulating film that functions as a protective layer is formed for the purpose of protecting the source electrode 46 a and the drain electrode 46 b from the deterioration due to the atmosphere, insulating the electronic device manufactured over the transistor, and the like. Also good. As this insulating film, for example, a film formed by heat-curing a photosensitive acrylic resin in a nitrogen atmosphere is used.

Hereinafter, a method for manufacturing the flexible electronic device 10 will be described.
As shown in FIG. 2A, for example, the thickness is 10 μm to the inner side on the surface 30a of the support substrate 30 excellent in dimensional stability (hereinafter also simply referred to as the substrate 30) through the adhesive layer 20. A flexible substrate 22 smaller than the 200 μm substrate 30 is laminated.
In this case, regarding the area of the adhesive surface of the flexible substrate 22, the adhesive layer 20 and the end 23 of the flexible substrate 22 are covered when a resin layer 24 described later is formed by spin coating, coating method, or the like. As shown in FIGS. 3A and 3B, the entire surface of the flexible substrate 22 is smaller than the adherend surface of the substrate 30. The flexible substrate 22 is bonded to the inner side of the surface 30a of the substrate 30 by shifting the sides so that the flexible substrate 22 and the support substrate 30 do not overlap each other. That is, the flexible substrate 22 has a smaller area than the substrate 30, and the flexible substrate 22 (adhesive layer 20) and the substrate 30 are arranged inside the surface 30a of the substrate 30 without aligning the sides with each other. Has been.
Specifically, although depending on the viscosity of the resin layer and the coating conditions described later, the horizontal distance d from the end of the flexible substrate 22 to the end of the substrate 30 is the flexible substrate 22 and the adhesive layer 20. Is preferably tan ⁻¹ (t / d) = 15 ° or less, and more preferably tan ⁻¹ (t / d) = 10 ° or less. For example, the flexible substrate 22 is processed into the above-described size before being laminated on the substrate 30 and bonded to the inside on the surface 30 a of the substrate 30 via the adhesive layer 20.

The flexible substrate 22 can be formed as follows in addition to processing to the above-mentioned size before bonding to the substrate 30. For example, as shown in FIG. 4A, after a flexible substrate (second flexible substrate) 25 is laminated on the entire surface of the substrate 30 via the adhesive layer 20, as shown in FIG. Further, the horizontal distance d to the end of the substrate 30 and the vertical distance t obtained by adding the thicknesses of the flexible substrate 22 and the adhesive layer 20 are tan ⁻¹ (t / d) = 15 ° or less, more preferably tan ^{−. The} removal region 32 is set on the outer edge of the substrate 30 so that ¹ (t / d) = 10 ° or less. The flexible substrate in the removal region 32 is removed together with the adhesive layer, and a flexible substrate 22 is laminated inside the surface 30a of the substrate 30 via the adhesive layer 20 as shown in FIG. May be. Examples of the setting method and the removing method of the removal region 32 include a method of cutting the adhesive layer 20 and the flexible substrate 25 on the substrate 30 to set the removal region 32 and then peeling the removal region 32. .

  An adhesive or a pressure-sensitive adhesive is preferably used for the adhesive layer 20 that adheres the flexible substrate 22 to the substrate 30. As the adhesive or pressure-sensitive adhesive, for example, a pressure-sensitive adhesive called an acrylic or urethane-based re-peeling agent can be used. Adhesive strength is sufficient when the flexible substrate 22 is processed. When the TFT 14 (electronic element) is peeled off, the flexible substrate 22 can be easily peeled off. The flexible substrate 22 is distorted, or the TFT 14 (electronic What has the adhesive force of the grade which does not destroy an element) is preferable. In particular, a photocurable adhesive layer is preferably used as an adhesive layer that satisfies the above requirements and can be easily bonded at room temperature.

  Next, as shown in FIG. 2B, a first heat treatment is performed. The first heat treatment is intended to volatilize at least a part of the uncured component or the residual solvent contained in the adhesive layer 20. The atmosphere at the time of the first heat treatment can be performed in, for example, an air atmosphere, an inert atmosphere such as nitrogen or Ar, and a reduced pressure environment. Moreover, as a temperature at the time of the first heat treatment, the lower one of the material used for the adhesive layer 20 and the heat-resistant temperature of the flexible substrate 22 is set as an upper limit.

Next, as shown in FIG. 2C, the exposed portion 30 b of the substrate 30 that is a part of the surface 30 a of the substrate 30, the end portion 23 of the adhesive layer 20 and the flexible substrate 22, and the flexible substrate 22. A resin layer 24 is formed so as to cover the surface.
The resin layer 24 is formed using, for example, a dip film forming method, a coating film forming method, or a spin coat film forming method. Among these methods, the spin coat film forming method is preferable from the viewpoint that the resin layer 24 having a thickness of 10 μm or less can be uniformly formed over a large area.
The resin layer 24 preferably has a thickness of 0.5 μm to 5.0 μm from the viewpoint of covering surface irregularities due to scratches, oligomers, mat particles, etc. on the surface of the flexible substrate 22. More preferably, it is 0 μm to 3.0 μm.

  For the resin layer 24, for example, a photo-curing or thermosetting acrylic resin or epoxy resin is used. As the resin to be the resin layer 24, in particular, from the viewpoint of surface flatness after curing and degassing property from the resin layer 24 itself, acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid butyl ester, acrylic acid 2- A resin containing an acrylic ester resin typified by ethylhexyl ester is preferably used.

  When a thermosetting resin is used as the resin to be the resin layer 24, the resin layer 24 is formed by applying a resin and then curing it by performing a second heat treatment shown in FIG. In addition, when using a photocurable resin as the resin to be the resin layer 24, after applying the resin, pre-baking, and after exposing with light of a predetermined wavelength and intensity to cure the applied resin, A resin layer 24 is formed by performing a second heat treatment shown in FIG. Thereby, the flexible substrate 22 is laminated via the adhesive layer 20 inside the surface 30 a of the substrate 30, and the laminated substrate 34 with the resin layer covered with the resin layer 24 is formed. In the laminated substrate 34 with a resin layer, the total pressure at a substrate temperature of 100 ° C. obtained by TDS (thermal desorption gas analysis) is 100 times or less than the total pressure at a substrate temperature of 50 ° C.

As shown in FIG. 2D, the second heat treatment is performed when a thermosetting resin is used for the resin layer 24, and at least a part of the uncured component or the residual solvent in the resin layer 24. It is performed for the purpose of volatilizing.
The atmosphere at the time of the heat treatment in the second heat treatment step can be, for example, an air atmosphere, an inert atmosphere such as nitrogen or Ar, and a reduced pressure environment. Among the heat resistant temperatures of the materials used for the conductive substrate 22 and the resin layer 24, the lower temperature is set as the upper limit.

  Next, as shown in FIG. 2E, the TFT 14 is formed on the surface 24 a of the resin layer 24, that is, on the surface of the laminated substrate 34 with a resin layer. This state is called a flexible electronic device manufacturing member. This flexible electronic device manufacturing member is a precursor for manufacturing a flexible electronic device.

The TFT 14 is formed using a manufacturing method including a vacuum process at least in part. For the formation of the TFT 14, patterning using a photolithography technique generally used for manufacturing an electronic element is used.
For forming the TFT 14, for example, a known method described in JP 2010-186860 A can be appropriately used as a method for forming a TFT on an organic plastic film. In addition, about each structure of TFT14, it can be set as the structure as described in Unexamined-Japanese-Patent No. 2010-186860.

Next, as shown in FIG. 2 (f), the flexible substrate 22 is peeled from the substrate 30. Thereby, the flexible electronic device 10 is formed.
When the flexible substrate 22 is peeled from the substrate 30, it depends on the material used for the adhesive layer 20. For example, the adhesive strength is reduced by, for example, a method of peeling from the edge after weakening the adhesive strength by ultraviolet irradiation or heat treatment. Method of peeling from the edge after weakening, Method of peeling from the edge by immersing the substrate 30 in warm water, Method of peeling mechanically while holding one end of the flexible substrate 22, There is a method of making a cut in a part and blowing off a gas such as air from there. Among these methods, an appropriate method is selected so as not to damage the substrate 12 and the TFT 14. Regardless of which method is used, it is desirable that the TFT 14 (electronic element) formed on the flexible substrate 22 be peeled off while suppressing the bending of the flexible substrate 22 so as not to be damaged or destroyed. .

  In the present invention, the support substrate 30 excellent in dimensional stability specifically refers to a hard and stable substrate having a thermal expansion coefficient of 10 ppm / ° C. or less and a water absorption of 0.1% or less. Examples of the substrate 30 include glass made of soda lime glass, borosilicate glass, quartz glass, and the like, ceramics such as alumina, zirconia, and silicon nitride, or a silicon wafer. The substrate 30 is preferably a glass substrate that is very commonly used in the manufacturing process of semiconductors and liquid crystal displays and is easy to handle.

  In addition, as described above, a photocurable adhesive layer is preferably used for the adhesive layer 20 that bonds the substrate 30 to the flexible substrate 22. For this reason, it is desirable for the substrate 30 to transmit ultraviolet rays, and a glass substrate is also preferable in this respect. Among glass substrates, a glass substrate of borosilicate glass typified by aluminoborosilicate glass has a high elastic modulus and a small coefficient of thermal expansion, so it is easy to ensure positional accuracy when forming TFT 14 (electronic element). Preferably used.

  The thickness of the substrate 30 is not particularly limited, but is preferably about 0.1 mm to 2.0 mm from the viewpoint of mechanical strength, ease of handling, transportation cost, and the like, More preferably, it is 1.5 mm.

Examples of the flexible substrate 22 include polyvinyl alcohol resins, polycarbonate derivatives (Teijin Limited: WRF), cellulose derivatives (cellulose triacetate, cellulose diacetate), polyolefin resins (Nippon ZEON Co., Ltd .: Zeonoa). , ZEONEX), polysulfone resin (polyethersulfone) norbornene resin (JSR Corporation: Arton), polyester resin (PET, PEN), polyimide resin, polyamide resin, polyarylate tree, polyether ketone A synthetic resin substrate having flexibility such as the like is preferable.
The thickness of the flexible substrate 22 is preferably 10 μm to 200 μm, and more preferably 30 μm to 150 μm, from the viewpoint of ease of handling.

When the flexible substrate 22 is bonded to the substrate 30, it is preferable to reduce excess adhesive or adhesive material by cleaning the substrate 30 to which the flexible substrate 22 is bonded.
As a cleaning method, for example, there is a method of irradiating ultrasonic waves in a detergent solution containing a surfactant or pure water, rinsing with pure water, and spin drying. The cleaning liquid used for cleaning, the intensity of ultrasonic irradiation, the temperature of the cleaning liquid, and the like are appropriately selected according to the flexible substrate 22 to be used, causing damage to the flexible substrate 22 or excessively high strength of the adhesive layer 20. It is necessary to carry out under appropriate conditions so as not to drop it.

In the present invention, in order to further suppress the degassing from the adhesive layer 20, the end 23 of the flexible substrate 22 bonded to the substrate 30 may be formed in a tapered shape to provide a taper. By providing the end portion 23 with a taper in this way, when the resin layer 24 is formed, the resin coverage at the end portion 23 and the exposed portion 30b of the substrate 30 is improved, and degassing from the adhesive layer 20 is prevented. Further suppression is possible.
As a method for providing the flexible substrate 22 and the end 23 of the adhesive layer 20 with a taper, a dry etching method using high-density plasma is suitable. An etching apparatus using microwaves or inductively coupled plasma (ICP) is suitable for a technique for obtaining high-density plasma. In particular, an ICP etching apparatus is suitable because it can easily control plasma and can cope with an increase in the area of a processing substrate.

In this embodiment, the TFT 14 (electronic element) is formed by using a vacuum process. The step of forming the TFT 14 (electronic element) by using this vacuum process is the process of forming the TFT 14 (electronic element) on the substrate. In the step of forming an element, a step of forming a TFT 14 (electronic element) including a vacuum process at least in part is shown. That is, the TFT 14 (electronic element) formation process is not necessarily performed by a vacuum process. For example, an electronic element formation process for forming a gate insulating film by a low pressure CVD method, a sputtering method, a vapor deposition method, or a PLD. A step of forming the semiconductor active layer or the electrode by the (pulse laser deposition) method may be included.
In the present embodiment, the electronic device to be formed preferably has a maximum temperature of the electronic device manufacturing process equal to or lower than the above-described second heat treatment temperature, and preferably can be manufactured by a low temperature process. . As what can be manufactured by such a low-temperature process, for example, there are TFTs using amorphous silicon, low-temperature polysilicon, and amorphous oxide semiconductor as an active layer.

  In the present embodiment, the first heat treatment is performed to volatilize at least a part of the uncured component or the residual solvent contained in the adhesive layer 20, and the second heat treatment is performed to remove the uncured component or the residual solvent in the resin layer 24. By volatilizing at least a part, degassing in a vacuum process when forming the TFT 14 can be suppressed. For this reason, when forming TFT14 as an electronic element, the influence on the electrical characteristic of the semiconductor layer which bears the main function of an electronic element is suppressed, and the characteristic change of the semiconductor layer which is not intended can be suppressed. Thereby, the yield of the flexible electronic device 10 can be improved, and the flexible electronic device 10 can be manufactured with a high yield.

Moreover, since the flexible electronic device 10 can be manufactured only by peeling the flexible substrate 22 from the support substrate 30 excellent in dimensional stability, the TFT 14 is prevented from being destroyed. In addition, since the flexible substrate 22 is laminated on the support substrate 30 having excellent dimensional stability, the TFT 14 is formed on the resin layer 24 with high patterning accuracy, that is, the positional accuracy of each component of the TFT 14. Highly formed. For this reason, the flexible electronic device 10 having the TFT 14 with good dimensional accuracy and the like can be manufactured with a high yield. Furthermore, since the flexible substrate 22 is simply peeled from the substrate 30 to obtain the flexible electronic device 10, the flexible electronic device 10 having a high definition and a large area can be manufactured with a high yield.
For this reason, the flexible electronic device 10 has high dimensional accuracy of the TFT 14 as described above, and also has stable characteristics of the semiconductor material constituting the TFT 14.

From the above, it is clear that the degassing in the vacuum process can be suppressed by using the laminated substrate 34 with the resin layer of the present embodiment, and further, on the resin layer 24 as described above. Since the TFT 14 can be formed with high dimensional accuracy, it can be suitably used for the flexible electronic device 10.
Note that the flexible electronic device 10 can be obtained simply by peeling the flexible substrate 22 on which the TFTs 14 are formed from the support substrate 30 having excellent dimensional stability. Moreover, since the TFT 14 has high accuracy such as patterning accuracy and the characteristics of the semiconductor material constituting the TFT 14 are stable, the flexible electronic device manufacturing member is suitable as a precursor for manufacturing the flexible electronic device 10. It is.

Next, a second embodiment of the present invention will be described.
FIG. 5: is typical sectional drawing which shows the flexible electronic device manufactured with the manufacturing method of the flexible electronic device of the 2nd Embodiment of this invention.
In the present embodiment, the same components as those of the flexible electronic device 10 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The flexible electronic device 10a of the present embodiment shown in FIG. 5 is different from the flexible electronic device 10 of the first embodiment (see FIG. 1) in the configuration of the substrate 50, and other than that of the first embodiment. Since it is the same structure as the flexible electronic device 10, the detailed description is abbreviate | omitted.

In the flexible electronic device 10a of this embodiment, the sealing layer 26 is provided on the resin layer 24 so that the substrate 50 further suppresses degassing from the resin layer 24 as compared with the substrate 12 of the first embodiment. It is provided. The TFT 14 is formed on the surface 50 a of the substrate 50.
Examples of the material of the sealing layer 26 include silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, silicon nitride carbide, silicon oxynitride carbide, germanium oxide, germanium nitride, germanium oxynitride, germanium oxycarbide, and nitride. Materials having excellent gas barrier properties such as germanium carbide, germanium oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, aluminum oxide carbide, aluminum nitride carbide, aluminum oxynitride carbide, yttrium oxide, tantalum oxide, and hafnium oxide are used.
In addition, the thickness of the sealing layer 26 is preferably 30 nm or more, and more preferably 100 nm or more from the viewpoint of obtaining a sufficient sealing effect.

Next, the manufacturing method of the flexible electronic device 10a of this embodiment is demonstrated.
FIGS. 6A to 6G are schematic views showing a method of manufacturing a flexible electronic device according to the second embodiment of the present invention in the order of steps.
In the present embodiment, the steps of FIGS. 6A to 6D are the same as the steps of FIGS. 2A to 2D of the first embodiment described above, and therefore detailed description thereof is omitted. Is omitted. For this reason, it demonstrates from the process of FIG.6 (e).

In the present embodiment, the sealing layer 26 is formed so as to cover the resin layer 24 as shown in FIG. Thereby, the flexible substrate 22 is laminated via the adhesive layer 20 inside the surface 30 a of the substrate 30, and further covered with the resin layer 24, and the resin layer in which the sealing layer 26 is formed on the resin layer 24. A laminated substrate 36 is formed. Also in this laminated substrate 36 with a resin layer, the total pressure at a substrate temperature of 100 ° C. obtained by TDS (thermal desorption gas analysis) is 100 times or less than the total pressure at a substrate temperature of 50 ° C.
Next, as shown in FIG. 6F, the TFT 14 is formed on the surface 26 a of the sealing layer 26, that is, on the surface of the multilayer substrate 36 with a resin layer. This state is called a flexible electronic device manufacturing member. Thereafter, the substrate 30 is peeled from the flexible substrate 22 as shown in FIG. Thereby, the flexible electronic device 10a is produced.
The manufacturing process of the TFT 14 shown in FIG. 6F of this embodiment and the peeling process of the substrate 30 shown in FIG. 6G are the same as those of FIGS. 4E and 4F of the first embodiment described above. Since it is a process, its detailed description is omitted.

In the present embodiment, as a method for forming the sealing layer 26, for example, a film forming method such as a sputtering method, a PLD (pulse laser deposition) method, an ion plating method, a CVD method, or a sol-gel method can be used.
In particular, since the entire surfaces of the substrate 30 and the flexible substrate 22 can be sealed, the formation method of the sealing layer 26 is preferably a film forming method using a CVD method or a sol-gel method. In any of the above film forming methods, it is desirable that the maximum temperature in the film forming process of the sealing layer 26 is equal to or lower than the above-described second heat treatment temperature.

  When the sealing layer 26 is formed by a vacuum process, it is preferable to use a vacuum apparatus having a load lock chamber as the film formation chamber, and the flexible substrate 22 is interposed in the film formation chamber via the adhesive layer 20. It is preferable to sufficiently degas before transferring the substrate on which the resin layer 24 is further adhered and the resin layer 24 is formed.

In the present embodiment, the effects of the first embodiment described above can be basically obtained. For this reason, the detailed description is abbreviate | omitted.
Furthermore, in this embodiment, by providing the sealing layer 26, degassing in a vacuum process can be further suppressed. As a result, when the TFT 14 is formed, unintended characteristic changes of the semiconductor layer can be further suppressed, the yield of the flexible electronic device 10a can be further improved, and the flexible electronic device 10a can be manufactured with a higher yield. be able to.
In addition, the laminated substrate 36 with a resin layer of this embodiment can be used suitably for the flexible electronic device 10a, similarly to the laminated substrate 34 with a resin layer of the first embodiment.

In any of the above-described embodiments, after the TFT 14 is formed, a third heat treatment may be performed in which the heat treatment is performed at a temperature equal to or lower than the heat treatment temperature in the second heat treatment (third heat treatment step).
In any of the above-described embodiments, the TFT 14 is taken as an example of the electronic element. However, the present invention is not limited to this, and various electronic elements such as a thin film capacitor, a thin film LED, and a thin film photoelectric conversion element can be manufactured. it can.

  The present invention is basically configured as described above. As mentioned above, although the manufacturing method of the flexible electronic device of this invention, the laminated substrate with a resin layer, and the flexible electronic device were demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, Of course, various improvements or modifications may be made.

  Hereinafter, although Example 1 and Comparative Examples 1-3 are given and the effect (characteristic) of this invention is clarified, this invention is not restrict | limited at all by Example 1 and Comparative Examples 1-3 shown below. Absent. First, Example 1 and Comparative Examples 1 to 3 will be described.

<Example 1>
In Example 1, a sample 60 shown in FIG. 7A was produced as follows, and this sample 60 was subjected to thermal desorption gas analysis (TDS) using EMD-WA1000S manufactured by Electronic Science Co., Ltd. Went.
In Example 1, first, a photo-curable acrylic adhesive was used for a synthetic quartz glass substrate 62 (total fine glass Co., Ltd .: T-4040) having a size of 10 mm □ × 1 mm (thickness). A PEN film (manufactured by Teijin DuPont Films Ltd .: Q65FA) having a size of 8 mm □ × 100 μm (thickness) was attached as the flexible substrate 64 through the adhesive layer 64. Then, using a UV exposure machine (low pressure mercury lamp light source), UV light was irradiated at an exposure amount of 360 mJ / cm ² and adhered to obtain a pasted sample.
Next, the applied sample was sequentially irradiated with ultrasonic waves in a cleaning solution containing a surfactant and glycol ether and pure water to remove excess adhesive, and then subjected to heat treatment at 120 ° C. for 1 hour in the atmosphere.
Next, a resin material (manufactured by JSR Co., Ltd .: JEM-531) is spin-coated on this attached sample, pre-baked at a temperature of 90 ° C. for 3 minutes, and then UV light is applied at an exposure amount of 140 mJ / cm ² . The resin layer 68 was formed by post-baking at a temperature of 210 ° C. for 1 hour. In this way, a sample 60 shown in FIG.
Next, TDS (temperature-programmed desorption gas analysis) was performed on the prepared sample 60 with respect to the gas types of M / z = 1 to 199. The result is shown in FIG.

<Comparative Example 1>
In Comparative Example 1, a sample 70 shown in FIG. 8A was prepared as follows. This sample 70 was subjected to temperature programmed desorption gas analysis (TDS) using EMD-WA1000S manufactured by Denshi Kagaku. Went.
The sample 70 of Comparative Example 1 includes two synthetic quartz glass substrates that are the same as the substrate 62 used in Example 1, and the same photo-curing acrylic adhesive as that used for the adhesive layer 64 in Example 1. It is what was pasted together.
In Comparative Example 1, exposure, cleaning, and heat treatment were performed under the same conditions for forming the adhesive layer 64 as in Example 1, two synthetic quartz glass substrates were bonded together, and a sample 70 shown in FIG. Produced.
Next, TDS was performed on the prepared sample 70 with respect to the gas type of M / z = 1 to 199. The result is shown in FIG.

<Comparative example 2>
In Comparative Example 2, a sample 72 shown in FIG. 9A was produced as follows, and this sample 72 was subjected to temperature programmed desorption gas analysis (TDS) using EMD-WA1000S manufactured by Electronic Science Co., Ltd. Went.
In FIG. 9A of Comparative Example 2, a sample 72 is obtained by using the same resin material as that of the resin layer 68 used in Example 1 on the same synthetic quartz glass substrate as that used in Example 1. Thus, the resin layer 68 is formed. Comparative Example 2 is a synthetic quartz glass substrate with a resin layer.
Next, TDS was performed on the produced sample 72 with respect to a gas type of M / z = 1 to 199. The result is shown in FIG.

<Comparative Example 3>
In Comparative Example 3, thermal desorption gas analysis (TDS) was performed on the sample 74 shown in FIG. 10A using an EMD-WA1000S manufactured by Denshi Kagaku.
In Comparative Example 3, the same PEN film as that used as the flexible substrate 66 in Example 1 was cut into a 10 mm square and constituted by a single PEN film.
In Comparative Example 3, TDS was performed on the sample 74 with respect to a gas type of M / z = 1 to 199. The result is shown in FIG.

In this example, compared with Comparative Example 1, as shown in FIG. 7B, the organic substance degassing M / z = 27, 39, 41, 93 due to the adhesive is 100 in particular. In addition to a significant decrease in the low temperature region around ℃, the degassing of M / z = 17,18, which is thought to be caused by water, has also decreased, and the degassing from the adhesive due to the heat treatment and sealing effect by the resin layer It was shown that can be significantly suppressed. In Example 1, as shown in FIG. 7B, as a result of TDS, the total pressure at the substrate temperature of 100 ° C. is 100 times or less of the total pressure at the substrate temperature of 50 ° C.
On the other hand, in Comparative Example 1, as shown in FIG. 8 (b), M / z = 27, 39, 41, 93, which are considered to be degassed organic substances, and M / z = 17, 18, which are considered to be caused by water. A large amount of degassing was confirmed. Although the specifics of M / z = 27, 39, 41, and 93, which are considered to be organic substances, are not clear, it is considered to be caused by the uncured component of the photocurable acrylic adhesive used for bonding the synthetic quartz glass substrate. . Degassing showed a peak in a low temperature region around 100 ° C., and it was shown that degassing from the adhesive was not sufficiently suppressed even though heat treatment was performed at 120 ° C. in advance.

Comparative Example 2 is a synthetic quartz glass substrate with a resin layer. As a result of TDS as in Example 1 and Comparative Example 1, degassing of M / z = 17, 18, 27, 39, 41, 93 at low temperature Since the TDS measurement result obtained in Example 1 does not have a peak that appears to be attributed to the organic material of the adhesive in the vicinity of 100 ° C., as in the measurement result of Comparative Example 2, Example 1 and Comparative Example It was shown that degassing from the adhesive can be suppressed by using the resin layer 68 used in 2.
Moreover, in Comparative Example 3, when focusing on M / z = 17, 18, 27, 39, 41, and 93 as in Example 1 and Comparative Examples 1 and 2, it was caused by water from 100 ° C. to 150 ° C. Possible degassing of M / z = 17 and 18 was observed, and degassing of M / z = 27 was observed at about 200 ° C., but M / z = 39, 41 and 93 were measured in Comparative Example 3. Within the temperature range, it was below the detection limit.

  As described above, in Example 1 which is a configuration of the present invention, the degassing of the organic substance due to the adhesive and the degassing which is considered to be caused by water are also reduced, and the adhesion effect due to the heat treatment and the sealing effect by the resin layer is reduced. It is clear that degassing from the agent can be greatly suppressed.

10, 10a Flexible electronic device 12, 50 Substrate 14 Thin film transistor (TFT)
20 Adhesive layer 22 Flexible substrate 24 Resin layer 26 Sealing layer 30 Support substrate (substrate) excellent in dimensional stability
40 Gate electrode 42 Gate insulating film 44 Active layer 46a Source electrode 46b Drain electrode

Claims (12)

Laminating a flexible substrate on the surface of a support substrate having excellent dimensional stability via an adhesive layer;
A first heat treatment step of heat-treating the support substrate on which the flexible substrate is laminated to release at least a part of a volatile component in the adhesive layer;
Forming a resin layer on the surface of the support substrate so as to cover the flexible substrate and the adhesive layer;
Heat-treating the support substrate on which the resin layer is formed, and a second heat treatment step for releasing at least part of the volatile components in the resin layer;
Forming an electronic element on the resin layer using a vacuum process;
And a step of peeling the flexible substrate from the support substrate.   The laminating step is performed by shifting the sides of the flexible substrate smaller than the support substrate so that the sides of the flexible substrate and the support substrate do not overlap each other. The method of manufacturing a flexible electronic device according to claim 1, wherein the method is a step of adhering to the surface of the support substrate.   The step of laminating includes a step of bonding a second flexible substrate on the surface of the support substrate via an adhesive layer, and removing an outer edge of the second flexible substrate together with the adhesive layer, Disposing the flexible substrate smaller than the support substrate on the surface of the support substrate by shifting the sides so that the sides of the flexible substrate and the support substrate do not overlap each other. The manufacturing method of the flexible electronic device of Claim 1.   The flexible resin according to any one of claims 1 to 3, wherein the resin layer is formed so as to cover an exposed portion of the adhesive layer, a surface of the flexible substrate, and a part of a surface of the support substrate. Electronic device manufacturing method.   5. The method according to claim 1, further comprising a step of cleaning the flexible substrate and the support substrate that are stacked via the adhesive layer before the first heat treatment step. 6. A method of manufacturing a flexible electronic device.   Before the step of forming the electronic element, the method further includes the step of providing a sealing layer on the resin layer, and the step of forming the electronic element forms the electronic element on the sealing layer. The manufacturing method of the flexible electronic device of any one of Claims 1-4.   The method of manufacturing a flexible electronic device according to claim 6, wherein the sealing layer is formed using a CVD method or a sol-gel method.   The flexible electronic device according to any one of claims 1 to 7, further comprising a third heat treatment step for heat treatment at a temperature equal to or lower than a heat treatment temperature in the second heat treatment step after the step of forming the electronic element. Manufacturing method.   The method of manufacturing a flexible electronic device according to claim 1, wherein the electronic element is a thin film transistor using an oxide semiconductor as an active layer. A support substrate with excellent dimensional stability;
On the surface of the support substrate, via a bonding layer, a flexible substrate that is smaller than the support substrate and laminated so that the sides of the support substrate and the support substrate do not overlap each other,
A resin layer provided on the surface of the support substrate so as to cover the flexible substrate and the adhesive layer;
The adhesive layer and the resin layer are formed by degassing at least a part of the volatile components therein, and the total pressure at the substrate temperature of 100 ° C. obtained by the temperature programmed desorption gas analysis is the substrate temperature of 50 ° C. A laminated substrate with a resin layer, characterized in that the total pressure is 100 times or less.   The laminated substrate with a resin layer according to claim 10, wherein a sealing layer is provided on the resin layer.   An electronic element is formed on the laminated substrate with a resin layer according to claim 10 or 11, wherein the flexible electronic device manufacturing member.

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