JP2018173542A - Element, semiconductor device, light-emitting device, display device, method for separation, method for manufacturing semiconductor device, method for manufacturing light-emitting device, and method for manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element, a semiconductor device, a display device, and a light-emitting device which have a smaller thickness and a smaller weight, to provide an element, a semiconductor device, a display device, and a light-emitting device which are not easily broken, or to provide an element, a semiconductor device, a display device, and a light-emitting device which are flexible.SOLUTION: The element includes: a substrate; a first resin layer in contact with the substrate; a second resin layer in contact with the first resin layer; and a first layer in contact with the second resin layer, the second resin layer being mainly made of polyimide resin. In the element, a material is detected that has a mass-to-charge ratio from 300 to 950, both inclusive, determined by an LC/MS (liquid chromatography mass analysis) measurement in the interface between the first and second resin layers. There are also provided a semiconductor device, a display device, and a light-emitting device which have the element.SELECTED DRAWING: Figure 1

Description

One embodiment of the present invention relates to an element, a semiconductor device, a display device, a peeling method, and a method for manufacturing the element display device.

Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, a driving method thereof, Alternatively, the production method thereof can be given as an example.

Semiconductor elements, display elements, and the like are made by laminating and processing various thin films on a glass substrate. Since glass has high heat resistance and high rigidity, it is possible to fabricate various elements on the substrate, and the elements fabricated on the glass substrate can be widely applied to displays, etc. Has been.

On the other hand, a glass substrate having sufficient rigidity requires a certain thickness, and if it becomes large, its weight increases and handling becomes difficult. In addition, since glass is brittle and vulnerable to impacts, it is easy to break.

In view of this, a semiconductor device and a display device using a resin substrate that is light and hardly damaged are attracting attention.

However, resins are generally vulnerable to heat and often cannot withstand the heat applied to produce high performance devices. Moreover, since it is easy to bend and to expand and contract, there is a problem that high-precision processing is difficult.

By the way, a semiconductor device and a display device using a resin substrate can be used with a curved surface or a different shape by using a flexible substrate. This is a feature that is difficult to achieve with an apparatus using a hard and brittle glass substrate.

Such semiconductor devices and display devices are expected to be applied to various uses. For example, Patent Document 1 discloses a flexible light-emitting device to which an organic EL (Electroluminescence) element is applied.

JP 2014-197522 A

An object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device which are reduced in thickness and weight. Another object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged. Another object of one embodiment of the present invention is to provide a flexible element, a semiconductor device, a display device, and a light-emitting device, respectively.

An object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device that are thin, lightweight, and inexpensive. Another object of one embodiment of the present invention is to provide an element, a semiconductor device, a display device, and a light-emitting device that are less likely to be damaged and are inexpensive. Another object of one embodiment of the present invention is to provide a flexible and inexpensive element, a semiconductor device, a display device, and a light-emitting device.

An object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device which are reduced in thickness and weight. Another object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged, or an embodiment of the present invention is an element having flexibility, It is an object to provide a method for manufacturing a semiconductor device, a display device, and a light-emitting device.

An object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that are thin, lightweight, and inexpensive. Another object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device which are less likely to be damaged and inexpensive. Another object of one embodiment of the present invention is to provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device that have flexibility and are inexpensive.

Note that the description of these problems does not disturb the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Issues other than these can be extracted from the description, drawings, and claims.

One embodiment of the present invention includes a substrate, a first resin layer formed in contact with the substrate, a second resin layer formed in contact with the first resin layer, and the second resin layer. A first layer formed in contact with the first resin layer, the second resin layer is composed mainly of a polyimide resin, and an LC is formed at an interface between the first resin layer and the second resin layer. / MS (liquid chromatography mass spectrometry) is a device in which a substance having a mass to charge ratio of 300 or more and 950 or less is detected.

Another embodiment of the present invention is an element in which a substance having a mass to charge ratio in the LC-MS measurement of 350 to 900 is detected in the above structure.

Another embodiment of the present invention is an element in which, in the above structure, 5 or more, preferably 10 or more substances of 300 to 950 are detected in the mass-to-charge ratio in the LC-MS measurement.

Another embodiment of the present invention is an element in which the substrate has flexibility in the above structure.

Another embodiment of the present invention is a semiconductor device in which a transistor is formed in the first layer in the above structure.

Another embodiment of the present invention is a semiconductor device in the above structure, in which the transistor includes a metal oxide in a channel formation region.

Another embodiment of the present invention is a display device in which the display element is formed in the first layer in the above structure.

In another embodiment of the present invention, a first resin layer containing polyimide as a main component is formed over a manufacturing substrate, a layer to be peeled is formed over the first resin layer, and the first resin layer By irradiating the resin layer with laser light, a separation region containing a substance having a mass to charge ratio of 300 to 950 in the LC / MS measurement is formed inside the first resin layer, and the manufacturing substrate and the object to be peeled are formed. It is the peeling method which isolate | separates a layer in the said isolation | separation area | region.

In another embodiment of the present invention, a first resin layer containing polyimide as a main component is formed over a formation substrate, a layer to be peeled including a transistor is formed over the first resin layer, By irradiating the first resin layer with laser light, a separation region containing a substance having a mass to charge ratio of 300 to 950 in the LC / MS measurement is formed inside the first resin layer, and the manufacturing substrate And the layer to be peeled off in the separation region.

Another structure of the present invention is a peeling method including a separation region including 5 or more, preferably 10 or more substances of 300 to 950 in the mass-to-charge ratio in the LC / MS measurement in the above structure.

Further, according to another embodiment of the present invention, in the above structure, a separation region containing a substance having a mass to charge ratio of 350 to 900 in the LC / MS measurement is formed inside the first resin layer, In this peeling method, the substrate and the layer to be peeled are separated at the separation region.

Another structure of the present invention is a peeling method including a separation region including 5 or more, preferably 10 or more substances of 350 to 900 in mass / charge ratio in the LC / MS measurement in the above structure.

Another embodiment of the present invention is a method for manufacturing a semiconductor device in which the transistor includes a metal oxide in a channel formation region in the above structure.

Another embodiment of the present invention is a method for manufacturing a display device in the above structure, in which the layer to be peeled includes a display element.

Another embodiment of the present invention is a method for manufacturing a light-emitting device in which the layer to be peeled includes a light-emitting element in the above structure.

Note that the light-emitting device in this specification includes an image display device using a light-emitting element. In addition, a module in which a connector such as an anisotropic conductive film or TCP (Tape Carrier Package) is attached to the light emitting element, a module in which a printed wiring board is provided at the end of TCP, or a COG (Chip On Glass) system in the light emitting element A module on which an IC (integrated circuit) is directly mounted may have a light emitting device. Furthermore, the luminaire may have a light emitting device.

One embodiment of the present invention can provide an element, a semiconductor device, a display device, and a light-emitting device which are reduced in thickness and weight. Alternatively, according to one embodiment of the present invention, an element, a semiconductor device, a display device, and a light-emitting device that are not easily damaged can be provided. Alternatively, an embodiment of the present invention can provide an integrated element or semiconductor device. Alternatively, according to one embodiment of the present invention, a flexible element, a semiconductor device, a display device, and a light-emitting device can be provided.

According to one embodiment of the present invention, an element, a semiconductor device, a display device, and a light-emitting device that are thin, light, and inexpensive can be provided. Alternatively, according to one embodiment of the present invention, an element, a semiconductor device, a display device, and a light-emitting device that are less likely to be damaged and inexpensive can be provided. Alternatively, an embodiment of the present invention can provide an integrated and inexpensive element and semiconductor device. Alternatively, according to one embodiment of the present invention, a flexible and inexpensive element, semiconductor device, display device, and light-emitting device can be provided.

One embodiment of the present invention can provide a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device which are reduced in thickness and weight. Alternatively, according to one embodiment of the present invention, a method for manufacturing an element, a semiconductor device, a display device, and a light-emitting device which are not easily damaged can be provided. Alternatively, according to one embodiment of the present invention, a method for manufacturing an integrated element or a semiconductor device can be provided. Alternatively, according to one embodiment of the present invention, a method for manufacturing a flexible element, a semiconductor device, a display device, and a light-emitting device can be provided.

One embodiment of the present invention can provide a thin film, a light weight, and a low-cost element, a semiconductor device, a display device, and a method for manufacturing a light-emitting device. Alternatively, according to one embodiment of the present invention, an element, a semiconductor device, a display device, and a light-emitting device which are less likely to be damaged and can be provided can be provided. Alternatively, according to one embodiment of the present invention, a method for manufacturing an integrated element and a semiconductor device at low cost can be provided. Alternatively, according to one embodiment of the present invention, a method for manufacturing a flexible element and a low-cost element, a semiconductor device, a display device, and a light-emitting device can be provided.

  Alternatively, another embodiment of the present invention can provide a new light-emitting element, a display module, a lighting module, a light-emitting device, a display device, an electronic device, and a lighting device, respectively. Alternatively, a light-emitting element with high emission efficiency can be provided. Alternatively, a display module, a lighting module, a light-emitting device, a display device, an electronic device, and a lighting device with low power consumption can be provided.

  One embodiment of the present invention may exhibit any one of the above effects.

The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process and an element. The figure showing a peeling process and a light-emitting device or a display apparatus. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process. The figure showing a peeling process and an element. The figure showing an element and a light-emitting device or a display apparatus. The figure showing a peeling process. FIG. 14 illustrates a light-emitting device or a display device. FIG. 10 illustrates an electronic device. FIG. 10 illustrates an electronic device. FIG. 10 illustrates an electronic device. The chromatograph in a PDA detector obtained by LC / MS analysis of the surface of a peeling layer. Absorption spectrum of polyimide film. The chromatograph in the PDA detector obtained by LC / MS analysis of comparative samples 1 and 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

Various methods have been proposed for separating elements formed on a manufacturing substrate such as a glass substrate from the substrate and bonding them to different substrates. In general, using a release layer made of a resin layer or an inorganic layer, forming a portion with weak adhesion at the interface or inside, and separating the elements formed on the production substrate from the production substrate, If the adhesion to the manufacturing substrate is weakened so that it can be easily separated, peeling in the formation process of the elements will occur. On the other hand, if the adhesion is too strong, damage due to the force applied during separation is possible. Increases sex.

Therefore, the present invention provides a peeling method capable of separating elements formed on a layer to be peeled from a manufacturing substrate with a high yield. Since the elements can be separated with a high yield, it is possible to suppress an increase in cost due to a product defect and to provide a product at a low cost.

In one embodiment of the present invention, separation is performed using a release layer using a polyimide resin. Since polyimide resin is relatively resistant to heat, the temperature limit for heating the element formed in the upper layer can be set high. Since sufficient heating can be performed, the reliability of elements can be improved. In addition, an element having a higher manufacturing temperature can be used. Specifically, since heating at 350 ° C. is also possible, it is easy to form a semiconductor element having good characteristics using a metal oxide.

First, a release layer made of a polyimide resin is formed over a manufacturing substrate. A commercially available polyimide resin can be used. Either a polyimide film formed by applying and imidizing a solution containing a polyimide precursor, or a polyimide film formed by applying a polyimide available, or a polyimide film formed by other methods It does not matter.

Subsequently, a layer to be peeled is formed on the peeling layer. The layer to be peeled may be a single layer or a layer composed of a plurality of layers, but is separated from the manufacturing substrate and transferred to another substrate or element to form elements to be used. For example, a transistor, a display element, a light emitting element, or the like corresponds to this. The peeled layer may contain a plurality of kinds of elements at the same time. Any other layer that can be formed over a manufacturing substrate can be formed as a layer to be peeled.

After the layer to be peeled is formed, a support substrate is attached to the side opposite to the glass substrate side of the layer to be peeled with a sealant or an adhesive. The support substrate may be used without being separated as it is, or a temporary substrate may be used on the assumption that the separation process is performed again.

After attaching the supporting substrate, the release layer is irradiated with laser light through the manufacturing substrate. The manufacturing substrate transmits laser light and has sufficiently high heat resistance, rigidity, and a sufficiently small expansion coefficient to form an element included in the layer to be peeled. Specifically, a glass substrate or the like is preferable.

Irradiation with laser light causes decomposition of molecules contained in the polyimide film, which is a layer to be peeled off, including polyimide molecules. As a result, the strength of the film in the portion where the decomposition has occurred is reduced, and the layer to be peeled can be separated from the support substrate with a sufficiently small force.

At the interface where separation occurs, there are various molecules generated by decomposition of the polyimide film. At this time, it is possible to prevent unintentional peeling from occurring, to prevent damage to the layer to be peeled, and to separate the production substrate and the layer to be peeled with an appropriate trigger and force. It was found that a degradation product having a specific molecular weight exists at the interface in a state having good peeling performance.

As described above, one or a plurality of substances having a molecular weight of 1000 or less exist at the interface exhibiting good peeling performance. Further, when the substance present at the peeling interface is washed away with an arbitrary organic solvent, and the obtained cleaning liquid is analyzed by LC / MS (liquid chromatography mass spectrometry), the mass-to-charge ratio (m / z) is 300 to 950, preferably One or a plurality of ions of 350 to 900 are detected. The better the releasability, the greater the number of substances whose mass-to-charge ratio (m / z) detected from the interface is 300 or more and 950 or less, preferably 350 or more and 900 or less, so 5 or more substances, more preferably 10 or more. Substances, more preferably 20 or more substances, more preferably 30 or more substances are detected. The number of substances detected is different if the retention times are different in liquid chromatographic separation in LC / MS analysis, even at the same mass to charge ratio or molecular weight. Further, in the chromatogram in the LC / MS photodiode array (PDA) detector, the interface having better peelability has a mass-to-charge ratio (m / z) of 300 to 950, preferably 350 to 900. The quantity, that is, the area intensity ratio increases. Substances or ions detected from the peeling interface are all substances produced as a result of decomposition of polyimide by laser irradiation, and do not include substances or ions derived from glass substrates or films used for peeling.

Therefore, by irradiating the laser beam so as to generate such a decomposition product, it becomes possible to manufacture a product that requires a peeling method with a high yield, and to provide them at a low cost.

In the case of using a glass substrate and using a polyimide film of about 1 μm as a release layer, for example,
As the laser oscillator of the laser beam, a XeCl excimer laser with a wavelength of 308 nm is used, the set energy of the oscillator is 980 mJ, the repetition frequency is 60 Hz, the scan speed is 11.7 mm / second, and the cross section of the laser beam is adjusted by adjusting the optical system. Can be formed into a 0.6 mm × 300 mm linear shape, an attenuator is used in the optical system, and the attenuation rate of the irradiation energy by the attenuator is 10%. Other lasers can also be used.

Note that a transistor is preferably formed in the layer to be peeled. In addition, the channel formation region of the transistor preferably includes a metal oxide. The metal oxide can function as an oxide semiconductor.

In the case where low temperature polysilicon (LTPS (Low Temperature Poly-Silicon)) is used for the channel formation region of the transistor, it is necessary to apply a temperature of about 500 ° C. to 550 ° C., and thus the release layer is required to have high heat resistance.

However, a transistor using a metal oxide for a channel formation region can be formed at 350 ° C. or lower, further 300 ° C. or lower. Therefore, high heat resistance is not required for the layer to be peeled. Therefore, the heat resistant temperature of the layer to be peeled can be lowered, and the range of material selection is widened. Further, the process can be simplified as compared with the case of using LTPS.

In this embodiment mode, since a separation region is formed inside the peeling layer, the thickness of the peeling layer is preferably 15 nm to 50 μm. Note that the thickness of the release layer is preferably 50 nm or more and 20 μm or less. By making the release layer as thin as possible within the range of the film thickness, it is possible to realize weight reduction, thinning, cost reduction, and improvement in flexibility.

Hereinafter, the element, the semiconductor device, the light-emitting device, and the display device of this embodiment will be described specifically together with a manufacturing method thereof.

Note that thin films (insulating films, semiconductor films, conductive films, etc.) constituting these elements and devices are formed by sputtering, chemical vapor deposition (CVD), vacuum evaporation, or pulsed laser deposition (PLD: Pulse). It can be formed using a laser deposition (ALD) method, an atomic layer deposition (ALD) method, or the like. The CVD method may be a plasma enhanced chemical vapor deposition (PECVD) method or a thermal CVD method. As an example of the thermal CVD method, a metal organic chemical vapor deposition (MOCVD) method may be used.

Thin films (insulating films, semiconductor films, conductive films, etc.) constituting display devices are spin coat, dip, spray coating, ink jet, dispense, screen printing, offset printing, doctor knife, slit coat, roll coat, curtain coat, knife It can be formed by coating or the like.

When processing the thin film, it can be processed using a lithography method or the like. Alternatively, an island-shaped thin film may be formed by a film formation method using a shielding mask. Alternatively, the thin film may be processed by a nanoimprint method, a sand blast method, a lift-off method, or the like. As a photolithography method, a resist mask is formed on a thin film to be processed, the thin film is processed by etching or the like, and the resist mask is removed. After forming a photosensitive thin film, exposure and development are performed. And a method for processing the thin film into a desired shape.

When light is used in the lithography method, for example, light used for exposure can be i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light in which these are mixed. In addition, ultraviolet light, KrF laser light, ArF laser light, or the like can be used. Further, exposure may be performed by an immersion exposure technique. Further, extreme ultraviolet light (EUV: Extreme Ultra-violet) or X-rays may be used as light used for exposure. Further, an electron beam can be used instead of the light used for exposure. It is preferable to use extreme ultraviolet light, X-rays, or an electron beam because extremely fine processing is possible. Note that a photomask is not necessary when exposure is performed by scanning a beam such as an electron beam.

For etching the thin film, a dry etching method, a wet etching method, a sand blasting method, or the like can be used.

[Production Method Example 1]
Hereinafter, the peeling method of one embodiment of the present invention is described using a display device as an example. First, the peeling layer 23 is formed over the manufacturing substrate 14 (FIG. 1).

FIG. 1A illustrates an example in which the resin layer 24 is formed over the entire surface of the manufacturing substrate 14 using a coating method. The method for forming the resin layer 24 is not limited to this, and a printing method or the like may be used.

The resin layer 24 can be formed using various resin materials (including a resin precursor). The resin layer 24 is preferably formed using a thermosetting material. In the present embodiment, the resin layer 24 is formed using a non-photosensitive material (also referred to as a non-photosensitive material).

The resin layer 24 is preferably formed using a material containing a polyimide resin or a polyimide resin precursor. The resin layer 24 can be formed using, for example, a material containing a polyimide resin and a solvent, or a material containing a polyamic acid and a solvent.

The resin layer 24 is preferably formed using a spin coater. By using the spin coating method, a thin film can be uniformly formed on a large substrate.

The release layer 23 is preferably formed using a solution having a viscosity of 5 cP or more and less than 500 cP, preferably 5 cP or more and less than 100 cP, more preferably 10 cP or more and 50 cP or less. The lower the viscosity of the solution, the easier the application. In addition, the lower the viscosity of the solution, the more air bubbles can be prevented and the better the film can be formed.

In addition, examples of the method for forming the resin layer 24 include dip, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coat, roll coat, curtain coat, knife coat, and the like.

The manufacturing substrate 14 has a rigidity that facilitates conveyance, a heat resistance that can withstand a temperature related to a manufacturing process of elements to be formed later, and is transparent to the laser light irradiated in the peeling process. Use one with light properties. Examples of materials that can be used for the manufacturing substrate 14 include glass, quartz, sapphire, and resin. Among these, glass has versatility and is preferable from the viewpoint of price and area increase. Examples of the glass include alkali-free glass, barium borosilicate glass, and alumino borosilicate glass.

Next, the peeling layer 23 is formed by performing a first heat treatment on the resin layer 24 (FIG. 1B).

By the first heat treatment, degassing components (for example, hydrogen, water, and the like) in the release layer 23 can be reduced. In particular, it is preferable to heat at a temperature equal to or higher than the manufacturing temperature of each layer formed on the release layer 23. Accordingly, degassing from the release layer 23 in the transistor manufacturing process can be significantly suppressed.

For example, in the case where the manufacturing temperature of the transistor is up to 350 ° C., the film to be the peeling layer 23 is preferably heated at 350 ° C. or more and 450 ° C. or less, more preferably 400 ° C. or less, and further heating at 375 ° C. or less. preferable. Accordingly, degassing from the release layer 23 in the transistor manufacturing process can be significantly suppressed.

It is preferable that the maximum temperature in manufacturing the transistor be equal to the temperature in the first heat treatment because the highest temperature in manufacturing the display device can be prevented by performing the first heat treatment.

By extending the treatment time, even in the case where the heating temperature is relatively low, it may be possible to achieve the same peelability as in the case where the heating temperature is higher. Therefore, when the heating temperature cannot be increased due to the configuration of the heating device, it is preferable to increase the treatment time.

The time for the first heat treatment is, for example, preferably 5 minutes to 24 hours, more preferably 30 minutes to 12 hours, and further preferably 1 hour to 6 hours. Note that the time of the first heat treatment is not limited to this. For example, when the first heat treatment is performed using an RTA (Rapid Thermal Annealing) method, it may be less than 5 minutes.

As the heating device, various devices such as an electric furnace and a device for heating an object to be processed by heat conduction or heat radiation from a heating element such as a resistance heating element can be used. For example, an RTA apparatus such as a GRTA (Gas Rapid Thermal Anneal) apparatus or an LRTA (Lamp Rapid Thermal Anneal) apparatus can be used. The LRTA apparatus is an apparatus that heats an object to be processed by radiation of light (electromagnetic waves) emitted from a lamp such as a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, or a high pressure mercury lamp. The GRTA apparatus is an apparatus that performs heat treatment using a high-temperature gas. Since the processing time can be shortened by using an RTA apparatus, it is preferable for mass production. Further, the heat treatment may be performed using an in-line heating apparatus.

Note that the thickness of the release layer 23 may change from the thickness of the resin layer 24 by heat treatment. For example, when the solvent contained in the resin layer 24 is removed, or curing progresses and the density increases, the volume decreases and the release layer 23 may become thinner than the resin layer 24 in some cases. Alternatively, when the heating atmosphere component is included during the heat treatment, the volume increases, and the release layer 23 may be thicker than the resin layer 24.

Before performing the first heat treatment, heat treatment (also referred to as pre-bake treatment) for removing the solvent contained in the resin layer 24 may be performed. The pre-baking temperature can be appropriately determined according to the material used. For example, it can be performed at 50 ° C. or higher and 180 ° C. or lower, 80 ° C. or higher and 150 ° C. or lower, or 90 ° C. or higher and 120 ° C. or lower. Alternatively, the first heat treatment may also serve as a prebake treatment, and the solvent contained in the resin layer 24 may be removed by the first heat treatment.

The release layer 23 has flexibility. The manufacturing substrate 14 is less flexible than the release layer 23.

The thermal expansion coefficient of the release layer 23 is preferably 0.1 ppm / ° C. or more and 50 ppm / ° C. or less, more preferably 0.1 ppm / ° C. or more and 20 ppm / ° C. or less, and 0.1 ppm / ° C. or more and 10 ppm / ° C. or less. More preferably, it is not higher than ° C. As the thermal expansion coefficient of the release layer 23 is lower, damage to the transistor and the like and cracks in the layer and the like that constitute the transistor can be suppressed due to heating.

Note that, when the release layer 23 is finally located on the display surface side of the display device, light from the display element is observed through the release layer 23. It is preferable that the light-transmitting property with respect to visible light is high.

Next, the layer to be peeled 21 is formed on the peeling layer 23. Although an example in which a transistor and a display element are formed as an element to be formed in the layer to be peeled 21 is described in this embodiment, one embodiment of the present invention is not limited to this, and the element is to be used separately from the manufacturing substrate 14. Any element may be formed.

First, the insulating layer 31 is formed over the peeling layer 23 as the layer to be peeled 21 (FIG. 1C).

The insulating layer 31 is formed at a temperature not higher than the heat resistance temperature of the release layer 23. It is preferable to form at a temperature lower than the temperature of the first heat treatment.

The insulating layer 31 can be used as a barrier layer that prevents impurities contained in the separation layer 23 from diffusing into a transistor or a display element in a separation layer to be formed later. For example, the insulating layer 31 preferably has a function of preventing moisture or the like contained in the release layer 23 from diffusing into a transistor or a display element when the release layer 23 is heated. Therefore, the insulating layer 31 preferably has a high barrier property.

As the insulating layer 31, for example, an inorganic insulating film such as a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, or an aluminum nitride film can be used. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, or the like may be used. Two or more of the above insulating films may be stacked. In particular, it is preferable that a silicon nitride film be formed over the separation layer 23 and a silicon oxide film be formed over the silicon nitride film.

Note that in this specification and the like, silicon oxynitride refers to a material having a higher oxygen content than nitrogen in the composition, and silicon nitride oxide has a nitrogen content higher than oxygen as the composition. Refers to material.

The inorganic insulating film is denser and has a higher barrier property as the deposition temperature is higher, and thus it is preferable to form the inorganic insulating film at a high temperature.

The substrate temperature during the formation of the insulating layer 31 is preferably room temperature (25 ° C.) or higher and 350 ° C. or lower, more preferably 100 ° C. or higher and 300 ° C. or lower.

Next, the transistor 40 is formed over the insulating layer 31 (FIG. 1C).

There is no particular limitation on the structure of the transistor included in the display device. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, any transistor structure of a top gate structure or a bottom gate structure may be employed. Alternatively, gate electrodes may be provided above and below the channel.

Here, a case where a transistor having a metal oxide layer 44 and having a bottom gate structure is manufactured as the transistor 40 is described. The metal oxide layer 44 can function as a semiconductor layer of the transistor 40. The metal oxide can function as an oxide semiconductor.

In this embodiment, an oxide semiconductor is used as a semiconductor of the transistor. It is preferable to use a semiconductor material with a wider band gap and lower carrier density than silicon because current in an off state of the transistor can be reduced.

The transistor 40 is formed at a temperature equal to or lower than the heat resistance temperature of the release layer 23. The transistor 40 is preferably formed at a temperature lower than that of the first heat treatment.

Specifically, first, the conductive layer 41 is formed on the insulating layer 31. The conductive layer 41 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

The substrate temperature during the formation of the conductive film is preferably room temperature to 350 ° C., more preferably room temperature to 300 ° C.

Each of the conductive layers included in the display device has a single-layer structure of a metal such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or an alloy containing the metal as a main component, or It can be used as a laminated structure. Or indium oxide, indium tin oxide (ITO), indium oxide containing tungsten, indium zinc oxide containing tungsten, indium oxide containing titanium, ITO containing titanium, indium zinc oxide, zinc oxide (ZnO) Alternatively, a light-transmitting conductive material such as ZnO containing gallium or ITO containing silicon may be used. Alternatively, a semiconductor such as polycrystalline silicon or an oxide semiconductor, or a silicide such as nickel silicide, which has been reduced in resistance by containing an impurity element or the like, may be used. Alternatively, a film containing graphene can be used. The film containing graphene can be formed, for example, by reducing a film containing graphene oxide formed in a film shape. Alternatively, a semiconductor such as an oxide semiconductor containing an impurity element may be used. Alternatively, a conductive paste such as silver, carbon, or copper, or a conductive polymer such as polythiophene may be used. The conductive paste is preferable because it is inexpensive. The conductive polymer is preferable because it is easy to apply.

Subsequently, the insulating layer 32 is formed. As the insulating layer 32, an inorganic insulating film that can be used for the insulating layer 31 can be used.

Subsequently, a metal oxide layer 44 is formed. The metal oxide layer 44 can be formed by forming a metal oxide film, forming a resist mask, etching the metal oxide film, and then removing the resist mask.

The substrate temperature during the formation of the metal oxide film is preferably 350 ° C. or less, more preferably from room temperature to 200 ° C., and further preferably from room temperature to 130 ° C.

The metal oxide film can be formed using one or both of an inert gas and an oxygen gas. Note that there is no particular limitation on the flow rate ratio of oxygen (oxygen partial pressure) during the formation of the metal oxide film. However, in the case of obtaining a transistor with high field effect mobility, the flow rate ratio of oxygen (oxygen partial pressure) during the formation of the metal oxide film is preferably 0% or more and 30% or less, and 5% or more and 30% or less. Is more preferably 7% or more and 15% or less.

The metal oxide film preferably contains at least indium or zinc. In particular, it is preferable to contain indium and zinc.

The metal oxide preferably has an energy gap of 2.0 eV or more, and more preferably 2.5 eV or more. More preferably, it is 3.0 eV or more. In this manner, off-state current of a transistor can be reduced by using a metal oxide having a wide energy gap.

The metal oxide film can be formed by a sputtering method. In addition, a PLD method, a PECVD method, a thermal CVD method, an ALD method, a vacuum evaporation method, or the like may be used.

Subsequently, a conductive layer 43a and a conductive layer 43b are formed. The conductive layer 43a and the conductive layer 43b can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask. The conductive layer 43a and the conductive layer 43b are connected to the metal oxide layer 44, respectively.

Note that when the conductive layer 43a and the conductive layer 43b are processed, part of the metal oxide layer 44 that is not covered with the resist mask may be thinned by etching.

The substrate temperature during the formation of the conductive film is preferably room temperature to 350 ° C., more preferably room temperature to 300 ° C.

As described above, the transistor 40 can be manufactured (FIG. 1C). In the transistor 40, part of the conductive layer 41 functions as a gate, part of the insulating layer 32 functions as a gate insulating layer, and the conductive layer 43a and the conductive layer 43b function as either a source or a drain, respectively. .

Next, an insulating layer 33 that covers the transistor 40 is formed (FIG. 1D). The insulating layer 33 can be formed by a method similar to that for the insulating layer 31.

As the insulating layer 33, an oxide insulating film such as a silicon oxide film or a silicon oxynitride film formed in an atmosphere containing oxygen is preferably used. Further, an insulating film that hardly diffuses and transmits oxygen such as a silicon nitride film is preferably stacked over the silicon oxide film or the silicon oxynitride film. An oxide insulating film formed in an atmosphere containing oxygen can be an insulating film from which a large amount of oxygen is easily released by heating. By performing heat treatment in a state where such an oxide insulating film that releases oxygen and an insulating film that hardly diffuses and transmits oxygen are stacked, oxygen can be supplied to the metal oxide layer 44. As a result, oxygen vacancies in the metal oxide layer 44 and defects at the interface between the metal oxide layer 44 and the insulating layer 33 can be repaired, and the defect level can be reduced. Thereby, a display device with extremely high reliability can be realized.

Through the above steps, the insulating layer 31, the transistor 40, and the insulating layer 33 can be formed over the separation layer 23 (FIG. 1D).

When an organic insulating film is used for the insulating layer 34, the temperature applied to the release layer 23 when the insulating layer 34 is formed is preferably room temperature to 350 ° C., more preferably room temperature to 300 ° C.

When an inorganic insulating film is used for the insulating layer 34, the substrate temperature during film formation is preferably room temperature or higher and 350 ° C. or lower, and more preferably 100 ° C. or higher and 300 ° C. or lower.

Next, an opening reaching the conductive layer 43 b is formed in the insulating layer 34 and the insulating layer 33.

After that, the conductive layer 61 is formed (FIG. 1E). A part of the conductive layer 61 functions as a pixel electrode of the light emitting element 60. The conductive layer 61 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

The conductive layer 61 is formed at a temperature not higher than the heat resistance temperature of the release layer 23. The conductive layer 61 is preferably formed at a temperature lower than that of the first heat treatment.

The substrate temperature during the formation of the conductive film is preferably room temperature to 350 ° C., more preferably room temperature to 300 ° C.

Next, the insulating layer 35 covering the end portion of the conductive layer 61 is formed (FIG. 1E). As the insulating layer 35, an organic insulating film or an inorganic insulating film that can be used for the insulating layer 31 can be used.

The insulating layer 35 is formed at a temperature not higher than the heat resistance temperature of the release layer 23. The insulating layer 35 is preferably formed at a temperature lower than that of the first heat treatment.

When an organic insulating film is used for the insulating layer 35, the temperature applied to the release layer when the insulating layer 35 is formed is preferably room temperature to 350 ° C., more preferably room temperature to 300 ° C.

When an inorganic insulating film is used for the insulating layer 35, the substrate temperature during film formation is preferably room temperature or higher and 350 ° C. or lower, more preferably 100 ° C. or higher and 300 ° C. or lower.

Next, an EL layer 62 and a conductive layer 63 are formed (FIG. 2A). A part of the conductive layer 63 functions as a common electrode of the light emitting element 60.

The EL layer 62 can be formed by a method such as an evaporation method, a coating method, a printing method, or a discharge method. When the EL layer 62 is formed separately for each pixel, the EL layer 62 can be formed by an evaporation method using a shadow mask such as a metal mask or an ink jet method.

For the EL layer 62, either a low molecular compound or a high molecular compound can be used, and an inorganic compound may be included.

The conductive layer 63 can be formed using a vapor deposition method, a sputtering method, or the like.

The conductive layer 63 is formed at a temperature not higher than the heat resistance temperature of the release layer 23 and not higher than the heat resistance temperature of the EL layer 62. Moreover, it is preferable to form at a temperature lower than the temperature of the first heat treatment.

As described above, the light-emitting element 60 can be formed (FIG. 2A). The light-emitting element 60 has a structure in which a conductive layer 61 that partially functions as a pixel electrode, an EL layer 62, and a conductive layer 63 that partially functions as a common electrode are stacked.

The light emitting element may be any of a top emission type, a bottom emission type, and a dual emission type. A conductive film that transmits visible light is used for the electrode from which light is extracted. In addition, a conductive film that reflects visible light is preferably used for the electrode from which light is not extracted. Here, it is assumed that a top emission type light emitting element is manufactured.

Next, an insulating layer 74 is formed so as to cover the conductive layer 63 (FIG. 2B). The insulating layer 74 functions as a protective layer that suppresses diffusion of impurities such as water into the light emitting element 60. The light emitting element 60 is sealed with an insulating layer 74. After the conductive layer 63 is formed, the insulating layer 74 is preferably formed without being exposed to the atmosphere.

The insulating layer 74 is formed at a temperature not higher than the heat resistance temperature of the release layer 23 and not higher than the heat resistance temperature of the light emitting element 60. The insulating layer 74 is preferably formed at a temperature lower than that of the first heat treatment.

The insulating layer 74 is preferably configured to include an inorganic insulating film having a high barrier property that can be used for the insulating layer 31 described above, for example. Alternatively, an inorganic insulating film and an organic insulating film may be stacked.

The insulating layer 74 can be formed using an ALD method, a sputtering method, or the like. The ALD method and the sputtering method are preferable because they can be formed at a low temperature. The use of the ALD method is preferable because the coverage of the insulating layer 74 is good.

Next, the protective layer 75 is formed over the insulating layer 74 (FIG. 2C). The protective layer 75 can be used as a layer located on the outermost surface of the display device. The protective layer 75 is preferably highly visible light transmissive.

It is preferable to use an organic insulating film that can be used for the above-described insulating layer 31 as the protective layer 75 because the surface of the display device can be prevented from being scratched or cracked.

FIG. 3A shows an example in which a substrate 75 a is attached to the insulating layer 74 using an adhesive layer 75 b instead of the protective layer 75.

Various resins of various curable adhesives such as an ultraviolet curable photocurable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used for the adhesive layer 75b. Further, an adhesive sheet or the like may be used.

Examples of the substrate 75a include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, and polyethersulfone (PES). ) Resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) Resin, ABS resin, cellulose nanofiber, etc. can be used. Various materials such as glass, quartz, resin, metal, alloy, and semiconductor may be used for the substrate 75a. Note that any substrate may be used as the substrate 75a when the substrate 75a is peeled again and attached to a different substrate. Further, in order to provide flexibility, a substrate having a material and a shape having flexibility to a degree necessary for the thickness and material of the substrate 75a may be used.

Next, the manufacturing substrate 14 and the release layer 23 are separated. In order to separate the separation layer 23, the separation layer 25 is formed inside the separation layer 23 by irradiating the separation layer 23 with laser light from the formation substrate 14 side (FIG. 3B). The separation region 25 is a portion where molecules constituting the release layer 23 are decomposed and become brittle by irradiation with laser light. Note that although the separation region 25 is formed in the separation layer 23 in the drawing, it may be formed at the interface with the manufacturing substrate 14 in the separation layer 23. When the release layer 23 is formed of a polyimide resin, the separation region 25 has at least one substance derived from ions having a mass-to-charge ratio of 300 to 950, preferably 350 to 900 in LC / MS measurement. included. Such a molecule is a product obtained by decomposing polyimide by laser irradiation, and can easily separate the manufacturing substrate 14 with an appropriate force, in the separation region 25 having good peeling performance. Observed. In the final product, since the molecule remains on the surface separated as the separation region 25, its presence can be confirmed by measurement.

The laser to irradiate is, for example,
As the laser oscillator of the laser beam, a XeCl excimer laser with a wavelength of 308 nm is used, the set energy of the oscillator is 980 mJ, the repetition frequency is 60 Hz, the scan speed is 11.7 mm / second, and the cross section of the laser beam is adjusted by adjusting the optical system. Can be formed into a 0.6 mm × 300 mm linear shape, an attenuator is used in the optical system, and the attenuation rate of the irradiation energy by the attenuator is 10%. Other lasers can also be used.

After that, for example, by applying a pulling force to the separation region 25 in the vertical direction, the layer to be peeled can be peeled from the manufacturing substrate 14 (FIG. 3C). Specifically, a part of the upper surface of the substrate 75a is adsorbed and pulled upward, whereby the layer to be peeled can be easily peeled off from the manufacturing substrate 14.

Here, at the time of peeling, a liquid containing water, such as water or an aqueous solution, is added to the peeling interface, and peeling is performed so that the liquid penetrates the peeling interface, whereby the peelability can be improved. Further, static electricity generated at the time of peeling can be prevented from adversely affecting a functional element such as a transistor (a semiconductor element is destroyed by static electricity).

A separation starting point may be formed by separating a part of the release layer 23 from the manufacturing substrate 14 before separation. For example, the separation starting point may be formed by inserting a sharp-shaped instrument such as a blade in the separation region 25. Alternatively, the separation layer 23 may be formed by cutting the release layer 23 with a sharp tool from the substrate 75a side. Alternatively, the separation starting point may be formed by a method using a laser such as a laser ablation method.

The separation region 25 exposed by separation from the manufacturing substrate 14 and the substrate 29 may be attached to each other using the adhesive layer 28 (FIG. 3D). The substrate 29 can function as a support substrate for the display device.

A material that can be used for the adhesive layer 75 b can be applied to the adhesive layer 28. A material that can be used for the substrate 75 a can be used for the substrate 29.

Through the above steps, a display device in which a metal oxide is applied to a channel formation region of a transistor and an EL element is applied can be manufactured.

The interface between the adhesive layer 28 and the release layer 23 of the display device manufactured in this way has at least a substance derived from ions having a mass-to-charge ratio of 300 to 950, preferably 350 to 900 in LC / MS measurement. 1 will be included. In LC / MS measurement, a substance derived from ions having a mass-to-charge ratio of 300 or more and 950 or less is generated by decomposition by laser irradiation, and the other part, that is, the interface between the peeling layer 23 and the layer to be peeled ( It is not detected at the interface with the insulating layer 31.

[Production Method Example 2]
In the following manufacturing method examples, description of the same portions as the manufacturing method examples described above may be omitted.

First, similarly to the manufacturing method example 1, the insulating layer 33 to the protective layer 75 are formed. In addition, when manufacturing these each component, it forms below the heat-resistant temperature of the peeling layer 23. FIG. Each of these components is preferably formed at a temperature lower than both the temperature of the first heat treatment and the temperature of the second heat treatment.

Then, the separation region 25 is formed in the peeling layer 23 at least in a portion where an element to be peeled is formed on the manufacturing substrate 14 by irradiation with laser light. (FIG. 4A) The type, wavelength, output, and the like of the laser conform to the manufacturing method 1. At this time, the release layer 23 is provided with a portion not irradiated with laser light. Since the separation region 25 is not formed in the portion where the laser beam is not irradiated, it can be prevented from being accidentally peeled off by transportation or the like.

Next, a separation starting point is formed in the release layer 23 (FIGS. 4B1 and 4B2).

For example, a sharp tool 65 such as a blade is inserted into the inner side of the end of the separation region 25 from the protective layer 75 side, and a cut 64 is made in a frame shape. This cut 64 is the starting point of separation.

Alternatively, a laser beam may be irradiated in a frame shape inside the separation region 25 in the release layer 23, and this may be used as a starting point for separation.

Note that in the case where a plurality of display devices are formed using a single manufacturing substrate (multiple manufacturing), a plurality of display devices are arranged inside the cut 64 as in the separation region 25 as illustrated in FIG. Good. Thus, a plurality of display devices can be peeled from the manufacturing substrate at once.

Alternatively, a plurality of separation regions 25 may be formed over one manufacturing substrate, and display elements and semiconductor elements may be separately formed at positions that become the separation regions 25 for each display device. FIG. 4B3 illustrates an example in which four separation regions are formed over a manufacturing substrate. Each display device can be peeled off at different timings by making a frame-like cut 64 in each of the four separation regions.

In the manufacturing method example 2, a part where the separation region 25 is formed and a part where the separation region 25 is not formed are provided on the manufacturing substrate 14. A portion where the separation region 25 is not formed is in a state where it is difficult to peel off from the manufacturing substrate 14 because the peeling layer 23 is not brittle. Therefore, it can suppress that the to-be-separated layer 21 peels from the preparation board | substrate 14 at the timing which is not intended. Then, by forming the separation starting point, the manufacturing substrate 14 and the layer to be peeled 21 can be separated at a desired timing. Therefore, the timing of peeling can be controlled and high peelability can be realized. Thereby, the yield of the peeling process and the manufacturing process of the display device can be increased.

Next, the manufacturing substrate 14 and the transistor 40 are separated (FIG. 5A).

In Production Method Example 2, the release layer 23 is irradiated with laser light to decompose resin molecules contained in the release layer 23, thereby forming a separation region 25 that is a weakened region. By doing so, the layer to be peeled 21 can be peeled from the manufacturing substrate 14.

Next, the separation region 25 in the separation layer 23 exposed by separation from the manufacturing substrate 14 and the substrate 29 are attached to each other using the adhesive layer 28 (FIG. 5B). The substrate 29 can function as a support substrate for the display device.

Through the above steps, a display device in which a metal oxide is applied to a channel formation region of a transistor and an EL element is applied can be manufactured.

[Configuration Example 1 of Display Device]
FIG. 6A is a top view of the display device 10A. 6B and 6C are examples of a cross-sectional view of the display portion 381 of the display device 10A and a cross-sectional view of a connection portion with the FPC 372, respectively.

The display device 10A can be manufactured using the manufacturing method example 2 described above. The display device 10 </ b> A can be held in a bent state or can be bent repeatedly.

The display device 10 </ b> A includes a protective layer 75 and a substrate 29. The protective layer 75 side is the display surface side of the display device. The display device 10A includes a display unit 381 and a drive circuit unit 382. An FPC 372 is attached to the display device 10A.

The conductive layer 43c and the FPC 372 are electrically connected through the connection body 76 (FIGS. 6B and 6C). The conductive layer 43c can be formed using the same material and step as the source and drain of the transistor.

As the connection body 76, various anisotropic conductive films (ACF: Anisotropic Conductive Film), anisotropic conductive pastes (ACP: Anisotropic Conductive Paste), and the like can be used.

The display device illustrated in FIG. 6C is different from the structure in FIG. 6B in that a transistor 49 is provided instead of the transistor 40 and a coloring layer 97 is provided over the insulating layer 33. . When the bottom emission type light emitting element 60 is used, a colored layer 97 may be provided between the light emitting element 60 and the substrate 29.

A transistor 49 illustrated in FIG. 6C includes a conductive layer 45 functioning as a gate electrode in addition to the structure of the transistor 40 illustrated in FIG.

The transistor 49 has a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. With such a structure, the threshold voltage of the transistor can be controlled. The transistor may be driven by connecting two gates and supplying the same signal thereto. Such a transistor can have higher field-effect mobility than other transistors, and can increase on-state current. As a result, a circuit that can be driven at high speed can be manufactured. Furthermore, the area occupied by the circuit portion can be reduced. By applying a transistor with a large on-state current, even if the number of wirings increases when the display device is enlarged or high-definition, signal delay in each wiring can be reduced, and display unevenness is suppressed. can do.

Alternatively, the threshold voltage of the transistor can be controlled by applying a potential for controlling the threshold voltage to one of the two gates and applying a potential for driving to the other of the two gates.

As described above, when these display devices are manufactured, the release layer 23 is irradiated with laser light to decompose the resin molecules contained in the release layer 23 and form the separation region 25 which is a weakened region. In addition, since the layer to be peeled 21 can be peeled from the manufacturing substrate 14 by being separated from the separation region, the adhesive layer 28 included in the display device manufactured by applying the manufacturing method of the display device of this embodiment mode. In the LC / MS measurement generated by decomposing the release layer 23 by irradiating the laser beam to the region between the contact layer and the release layer 23 (interface between the adhesive layer 28 and the release layer 23), the mass-to-charge ratio Is at least one of substances derived from ions of 300 to 950. The release layer 23 in which these molecular weight molecules exist has a good release performance while suppressing the release layer 21 from being unintentionally peeled off by appropriately decomposing the molecules. Thus, a display device can be manufactured with high yield.

Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance Spectroscopy ( ¹ H-NMR), Gas Chromatograph Mass Spectrometry (GC / MS), Liquid Chromatograph Mass Spectrometry (LC / MS), Using one or more analysis methods such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS), By analyzing the surface (separation region 25) or the surface of the adhesive layer 28, the molecules present at the interface between the release layer 23 and the adhesive layer 28 can be confirmed.

In order to perform analysis by LC / MS, the surface on the peeling interface side of the glass substrate after peeling and the surface on the peeling interface side of the layer to be peeled are combined with any solvent (toluene, chloroform, 1,1,3,3). -Wash off with hexafluoro-2-propanol (abbreviation: HFIP), etc., and dilute the resulting cleaning solution with any solvent (such as acetonitrile, preferably an organic solvent used for LC / MS measurement) to prepare a measurement sample .

When analyzing a display device, first, in the transistor structure of the display device, a layer to be a peeling interface, for example, a layer in which polyimide and an adhesive (epoxy resin or the like) are in contact is specified. Examples of the analysis method used for specifying the peeling interface include TEM-EDX (transmission electron microscope-energy dispersive X-ray analysis, etc.). A method of analyzing the vicinity of the identified interface by an analysis method that can obtain molecular weight distribution information in the depth direction such as TOF-SIMS (time-of-flight secondary ion mass spectrometry), or MALDI-MS (matrix-assisted laser desorption ionization mass) The analysis can be performed by using an analysis method that can obtain molecular weight distribution information in the horizontal direction. Moreover, after the peeling interface is specified by the above-mentioned method, after peeling at the peeling interface and exposing the surface, the surface of both peeling interfaces is washed away with an arbitrary solvent (toluene, chloroform, HFIP, etc.). The obtained cleaning solution can be diluted with an arbitrary solvent (such as acetonitrile, which is preferably an organic solvent used for LC / MS measurement) to prepare a measurement sample, and LC / MS analysis can be performed.

[Production Method Example 3]
First, similarly to the manufacturing method example 2, the separation layer 23 to the insulating layer 31 are formed over the manufacturing substrate 14 (FIG. 7A).

Next, the transistor 80 is formed over the insulating layer 31 (FIG. 7B).

Here, a case where a transistor having a metal oxide layer 83 and two gates is manufactured as the transistor 80 is shown.

The transistor 80 is formed at a temperature equal to or lower than the heat resistance temperature of the release layer 23. It is preferable to form at a temperature lower than both the temperature of the first heat treatment and the temperature of the second heat treatment.

Specifically, first, the conductive layer 81 is formed on the insulating layer 31. The conductive layer 81 can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask.

Subsequently, the insulating layer 82 is formed. As the insulating layer 82, an inorganic insulating film that can be used for the insulating layer 31 can be used.

Subsequently, a metal oxide layer 83 is formed. The metal oxide layer 83 can be formed by forming a metal oxide film, forming a resist mask, etching the metal oxide film, and then removing the resist mask. A material that can be used for the metal oxide layer 44 can be used for the metal oxide layer 83.

Subsequently, an insulating layer 84 and a conductive layer 85 are formed. As the insulating layer 84, an inorganic insulating film that can be used for the insulating layer 31 can be used. The insulating layer 84 and the conductive layer 85 are formed by forming an insulating film to be the insulating layer 84 and a conductive film to be the conductive layer 85, then forming a resist mask, etching the insulating film and the conductive film, and then resisting the resist. It can be formed by removing the mask.

Next, the insulating layer 33 that covers the metal oxide layer 83, the insulating layer 84, and the conductive layer 85 is formed. The insulating layer 33 can be formed by a method similar to that for the insulating layer 31.

The insulating layer 33 preferably contains hydrogen. Hydrogen contained in the insulating layer 33 diffuses into the metal oxide layer 83 in contact with the insulating layer 33, and a part of the metal oxide layer 83 has a low resistance. Since the metal oxide layer 83 in contact with the insulating layer 33 functions as a low resistance region, the on-state current of the transistor 80 can be increased and the field-effect mobility can be improved.

Next, an opening reaching the metal oxide layer 83 is formed in the insulating layer 33.

Subsequently, a conductive layer 86a and a conductive layer 86b are formed. The conductive layers 86a and 86b can be formed by forming a conductive film, forming a resist mask, etching the conductive film, and then removing the resist mask. The conductive layer 86a and the conductive layer 86b are electrically connected to the metal oxide layer 83 through the opening of the insulating layer 33, respectively.

As described above, the transistor 80 can be manufactured (FIG. 7B). In the transistor 80, part of the conductive layer 81 functions as a gate, part of the insulating layer 84 functions as a gate insulating layer, part of the insulating layer 82 functions as a gate insulating layer, and part of the conductive layer 85 Functions as a gate. The metal oxide layer 83 has a channel region and a low resistance region. The channel region overlaps with the conductive layer 85 with the insulating layer 84 interposed therebetween. The low resistance region has a portion connected to the conductive layer 86a and a portion connected to the conductive layer 86b.

Next, the layers from the insulating layer 34 to the light-emitting element 60 are formed over the insulating layer 33 (FIG. 7C). Reference can be made to Production Method Example 1 for these steps.

Moreover, the process of FIG. 8 (A) and (B) is performed independently of the process of FIG. 7 (A)-(C). Similar to the process of forming the release layer 23 on the manufacturing substrate 14, the release layer 93 is formed on the manufacturing substrate 91.

Next, the insulating layer 95 is formed over the peeling layer 93. Next, a colored layer 97 and a light shielding layer 98 are formed over the insulating layer 95 (FIG. 8B).

For the insulating layer 95, the description of the insulating layer 31 can be used.

As the colored layer 97, a color filter or the like can be used. The colored layer 97 is disposed so as to overlap the display area of the light emitting element 60.

As the light shielding layer 98, a black matrix or the like can be used. The light shielding layer 98 is disposed so as to overlap the insulating layer 35.

Next, the surface of the manufacturing substrate 14 on which the transistor 80 or the like is formed and the surface of the manufacturing substrate 91 on which the colored layer 97 or the like is formed are attached to each other using the adhesive layer 99 (FIG. 8C). .

Next, the release layer 23 is irradiated with laser light to form a separation region 25 (FIG. 9A), and then a separation starting point is formed (FIG. 9B). Either the manufacturing substrate 14 or the manufacturing substrate 91 may be separated first. Here, an example in which the manufacturing substrate 14 is separated before the manufacturing substrate 91 is shown.

The laser irradiation conditions for forming the separation region 25 may be performed in the same manner as the method described in the manufacturing method example 1.

As a method of forming the separation starting point, for example, there is a method of irradiating a laser beam 66 in a frame shape on the inner side of the separation region 25 in the separation layer 23a from the manufacturing substrate 14 side (laser shown in FIG. 9C). (See light irradiation position 67). This method is suitable when a hard substrate such as glass is used for the manufacturing substrate 14 and the manufacturing substrate 91.

There is no particular limitation on the laser used to form the separation starting point. For example, a continuous wave laser or a pulsed laser can be used. Laser light irradiation conditions (frequency, power density, energy density, beam profile, and the like) are appropriately controlled in consideration of the thickness of the manufacturing substrate and the release layer 23, the position of the separation region 25, the material, and the like.

In the manufacturing method example 4, when the laser beam irradiation for forming the separation region 25 is performed, a portion where the laser beam is irradiated and a portion where the laser beam is not irradiated are provided on the peeling layer 23. A separation region 25 is formed in a portion irradiated with laser light to form the separation region 25, and the separation layer 23 is easily separated from the manufacturing substrate 14. On the other hand, as for the part where the separation region is not formed, there is no fragile part in the peeling layer 23, so that the peeling layer 23 remains difficult to separate from the manufacturing substrate 14. Thereby, it can suppress that the to-be-separated layer 21 peels from the production substrate 14 at the timing which is not intended. Similarly, when laser light irradiation for forming the separation region 94 is performed from above the manufacturing substrate 91, the peeling layer 93 is not intended from the manufacturing substrate 91 by providing a portion that is irradiated with laser light and a portion that is not irradiated. Separation at the timing can be suppressed.

Then, by forming the separation starting point on only one of the release layer 23 and the release layer 93, the manufacturing substrate 14 and the manufacturing substrate 91 can be separated in separate steps. Thereby, the yield of the peeling process and the manufacturing process of the display device can be increased.

Next, when the separation starting point is formed in the separation layer 23 (separation region 25) from the manufacturing substrate 14 side, the manufacturing substrate 14 and the transistor 80 are separated (FIG. 10A). Here, an example in which an inner portion irradiated with the laser light 66 in a frame shape (also referred to as an inner portion of the laser light irradiation region 67 shown in FIG. 9B) is peeled from the manufacturing substrate 14 is shown. FIG. 10A shows an example in which separation occurs in the adhesive layer 99 in the outer portion irradiated with the laser beam 66 in a frame shape (the adhesive layer 99 coheses and breaks), but the present invention is not limited to this. . For example, the adhesive layer 99 may be separated from the insulating layer 95 or the insulating layer 35 outside the irradiation region 67 (also referred to as interface breakdown or adhesive breakdown).

Next, the separation layer 23 exposed by separation from the manufacturing substrate 14 and the substrate 29 are attached to each other using the adhesive layer 28 (FIG. 10B). The substrate 29 functions as a support substrate for the display device.

Next, a separation starting point is formed in the separation layer 93 (separation region 94) (FIG. 11A).

In FIG. 11A, a sharp tool 65 such as a blade is inserted from the substrate 29 side to the inner side of the end of the separation region 94 in the release layer 93, and a frame is cut. This is suitable when a resin is used for the substrate 29.

Alternatively, similarly to the case where the separation starting point is formed in the separation layer 23, the separation layer 93 may be irradiated with laser light in a frame shape from the manufacturing substrate 91 side.

By forming the separation starting point, the manufacturing substrate 91 and the separation layer 93 can be separated at a desired timing. Therefore, the timing of peeling can be controlled and high peelability can be realized. Thereby, the yield of the peeling process and the manufacturing process of the display device can be increased.

Next, the manufacturing substrate 91 and the transistor 80 are separated (FIG. 11B). Here, an example in which an inner portion having a frame-like cut is peeled from the manufacturing substrate 91 is shown.

Next, the separation layer 93 exposed by being separated from the manufacturing substrate 91 and the substrate 22 are attached to each other using the adhesive layer 13 (FIG. 12A). The substrate 22 can function as a support substrate for the display device.

In FIG. 12A, light emitted from the light-emitting element 60 is extracted outside the display device through the coloring layer 97 and the peeling layer 93. Therefore, the visible light transmittance of the release layer 93 is preferably high.

The peeling layer 93 may be removed. Thereby, the light extraction efficiency of the light emitting element 60 can be further increased. FIG. 12B shows an example in which the peeling layer 93 is removed and the substrate 22 is bonded to the insulating layer 95 using the adhesive layer 13.

A material that can be used for the adhesive layer 75 b can be applied to the adhesive layer 13.

A material that can be used for the substrate 75 a can be used for the substrate 22.

Manufacturing Method Example 4 is an example of manufacturing a display device by performing the peeling method of one embodiment of the present invention twice. In one embodiment of the present invention, since the functional elements and the like included in the display device are formed over the manufacturing substrate, the flexible substrate has a high position even when a high-definition display device is manufactured. Alignment accuracy is not required. Therefore, a flexible substrate can be attached easily.

As described above, when these display devices were manufactured, the release layer 23 and the release layer 93 were irradiated with laser light, whereby the resin molecules contained in the release layer 23 and the release layer 93 were decomposed and became brittle. The element formation region can be peeled from the manufacturing substrate 14 and the manufacturing substrate 91 by forming the isolation region 25 and the isolation region 94 which are regions and separating from the isolation region, so that the display device of this embodiment mode is manufactured. A region between the adhesive layer 28 and the release layer 23 (an interface between the adhesive layer 28 and the release layer 23) and a region between the adhesive layer 13 and the release layer 93 included in the display device manufactured by applying the method ( In the LC / MS measurement generated by decomposing the release layer 23 or the release layer 93 by irradiating the laser beam on the interface between the adhesive layer 13 and the release layer 93, the mass to charge ratio is 300 or more and 9 0 material derived from the following ions are present one or more. The release layer 23 and the release layer 93 in which molecules having these molecular weights are present have a good release performance while suppressing unintentional release by appropriately decomposing molecules, so that a display device with a high yield is obtained. Can be manufactured.

[Modification]
In Production Method Example 4 (FIG. 18C), the case where the adhesive layer 99 is also formed outside the separation region 25 and the separation region 94 is shown. The adhesion on the outside of the separation region is high, and if separation is performed as it is, the separation yield may be lowered, such as a separation failure.

Therefore, as shown in FIGS. 13A and 13B, the adhesive layer 99 is configured not to overlap the outer side of the separation region 25 and the outer side of the separation region 94, thereby reducing peeling defects. It becomes.

For example, when an adhesive having low fluidity or an adhesive sheet is used for the adhesive layer 99, the adhesive layer 99 can be easily formed in an island shape (FIG. 13A).

Alternatively, a frame-shaped partition wall 96 may be formed, and an adhesive layer 99 may be filled and cured inside the partition wall 96 (FIG. 13B).

When the partition wall 96 is used as a component of the display device, it is preferable to use a cured resin for the partition wall 96. At this time, it is preferable that the partition wall 96 also does not overlap the outside of the separation region 25 and the outside of the separation region 94.

In the case where the partition wall 96 is not used as a component of the display device, it is preferable to use an uncured or semi-cured resin for the partition wall 96. At this time, the partition wall 96 may overlap one or both of the outside of the separation region 25 and the outside of the separation region 94.

In the present embodiment, an example in which an uncured resin is used for the partition wall 96 and the partition wall 96 does not overlap the outside of the separation region 25 and the outside of the separation region 94 is shown.

A method for forming a separation starting point in a configuration in which the adhesive layer 99 does not overlap the outside of the separation region 25 and the outside of the separation region 94 will be described. Below, the example which peels the production board | substrate 91 is shown. A similar method can be used when the manufacturing substrate 14 is peeled off.

14A to 14E, an irradiation position of the laser beam 66 in the case where the manufacturing substrate 91 and the separation layer 93 are separated will be described.

As shown in FIG. 14A, the separation starting point can be formed by irradiating laser light 66 to at least one region of the separation layer 94 where the separation region 94 and the adhesive layer 99 overlap.

Since it is preferable that the force that separates the manufacturing substrate 91 and the release layer 93 is concentrated at the separation starting point, it is preferable to form the separation starting point near the end portion rather than the central portion of the adhesive layer 99. In particular, it is preferable to form the separation starting point in the vicinity of the corner portion, in the vicinity of the end portion, as compared with the vicinity of the side portion.

FIGS. 14B to 14E show an example of an irradiation region 67 of laser light.

FIG. 14B shows a laser light irradiation region 67 at one corner of the adhesive layer 99.

By irradiating the laser beam continuously or intermittently, a solid line or broken line starting point can be formed. In FIG. 14C, laser light irradiation regions 67 are shown at three corners of the adhesive layer 99. FIG. 16D illustrates an example in which the laser light irradiation region 67 is in contact with one side of the adhesive layer 99 and extends along one side of the adhesive layer 99. As shown in FIG. 14E, the laser light irradiation region 67 is located not only in the region where the adhesive layer 99 and the separation region 94 overlap, but also in the region where the partition wall 96 and the separation region 94 which are not cured are overlapped. Also good.

After that, the manufacturing substrate 91 and the separation layer 93 can be separated. Note that part of the partition wall 96 may remain on the formation substrate 14 side. The partition wall 96 may be removed or may not be removed and may proceed to the next step.

[Configuration Example 2 of Display Device]
FIG. 15A is a top view of the display device 10B. FIG. 15B is an example of a cross-sectional view of the display portion 381 of the display device 10B and a cross-sectional view of a connection portion with the FPC 372.

The display device 10B can be manufactured using the manufacturing method example 5 described above. The display device 10B can be held in a bent state, bent repeatedly, or the like.

The display device 10 </ b> B includes a substrate 22 and a substrate 29. The substrate 22 side is the display surface side of the display device 10B. The display device 10B includes a display unit 381 and a drive circuit unit 382. An FPC 372 is attached to the display device 10B.

The conductive layer 86c and the FPC 372 are electrically connected through the connection body 76 (FIG. 15B). The conductive layer 86c can be formed using the same material and the same process as the source and drain of the transistor.

As described above, when these display devices are manufactured, the release layer 23 is irradiated with laser light to decompose the resin molecules contained in the release layer 23 and form the separation region 25 which is a weakened region. Then, the element formation region can be peeled from the manufacturing substrate 14 by separating the separation layer 93 from the separation region. Therefore, in a region (an interface between the adhesive layer 28 and the release layer 23) between the adhesive layer 28 and the release layer 23 included in the display device manufactured by applying the method for manufacturing the display device of this embodiment, In LC / MS measurement generated by decomposing the release layer 23 by irradiation with laser light, one or more substances derived from ions having a mass to charge ratio of 300 to 950 are present. The peeling layer 23 in which molecules having these molecular weights are present has a good peeling performance while suppressing unintended peeling by appropriately decomposing the molecules, and thus a display device is manufactured with a high yield. Can do.

This embodiment can be combined with any of the other embodiments as appropriate. In this specification, in the case where a plurality of structure examples are given in one embodiment, any of the structure examples can be combined as appropriate.

(Embodiment 1)
In this embodiment, a display device and a manufacturing method thereof according to one embodiment of the present invention will be described with reference to drawings.

The display device of this embodiment includes a first display element that reflects visible light and a second display element that emits visible light.

The display device of this embodiment has a function of displaying an image using one or both of light reflected by the first display element and light emitted by the second display element.

As the first display element, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as a first display element, in addition to a shutter-type MEMS (Micro Electro Mechanical System) element, an optical interference-type MEMS element, a microcapsule type, an electrophoretic method, an electrowetting method, and an electronic powder fluid (registered trademark) An element to which a method or the like is applied can be used.

A light-emitting element is preferably used for the second display element. The light emitted from such a display element is not affected by external light in brightness or chromaticity, so that it has high color reproducibility (wide color gamut), high contrast, and vivid display. Can do.

For the second display element, a self-luminous light emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), or a QLED (Quantum-Dot Light Emitting Diode) can be used.

The display device of the present embodiment includes a first mode for displaying an image using only the first display element, a second mode for displaying an image using only the second display element, and a first mode There is a third mode in which an image is displayed using the display element and the second display element, and these modes can be used by switching automatically or manually.

In the first mode, an image is displayed using the first display element and external light. Since the first mode does not require a light source, it is an extremely low power consumption mode. For example, when external light is sufficiently incident on the display device (for example, in a bright environment), display can be performed using light reflected by the first display element. For example, it is effective when the external light is sufficiently strong and the external light is white light or light in the vicinity thereof. The first mode is a mode suitable for displaying characters. In the first mode, light that reflects external light is used, so that it is possible to perform display that is kind to the eyes, and there is an effect that the eyes are less tired.

In the second mode, an image is displayed using light emission by the second display element. Therefore, an extremely vivid display (high contrast and high color reproducibility) can be performed regardless of illuminance and chromaticity of external light. For example, it is effective when the illuminance is extremely low, such as at night or in a dark room. When the surroundings are dark, the user may feel dazzled when performing bright display. In order to prevent this, it is preferable to perform display with reduced luminance in the second mode. Thereby, in addition to suppressing glare, power consumption can also be reduced. The second mode is a mode suitable for displaying vivid images (still images and moving images).

In the third mode, display is performed using both reflected light from the first display element and light emission from the second display element. While displaying more vividly than in the first mode, it is possible to suppress power consumption as compared with the second mode. For example, it is effective when the illuminance is relatively low, such as under room lighting or in the morning or evening hours, or when the chromaticity of outside light is not white. Further, by using light in which reflected light and light emission are mixed, it is possible to display an image that makes it feel as if you are looking at a painting.

With such a configuration, it is possible to realize a highly visible and highly convenient display device or an all-weather display device regardless of ambient brightness.

The display device of this embodiment includes a plurality of first pixels each including a first display element and a plurality of second pixels each including a second display element. The first pixels and the second pixels are preferably arranged in a matrix.

Each of the first pixel and the second pixel can include one or more subpixels. For example, the pixel has a configuration with one subpixel (white (W), etc.), a configuration with three subpixels (red (R), green (G), and blue (B), or three colors, or Yellow (Y), cyan (C), magenta (M), etc.) or a configuration having four sub-pixels (red (R), green (G), blue (B), white (W) Or four colors of red (R), green (G), blue (B), yellow (Y), etc.) can be applied.

The display device of this embodiment can be configured to perform full-color display in both the first pixel and the second pixel. Alternatively, the display device in this embodiment can have a structure in which the first pixel performs monochrome display or grayscale display, and the second pixel performs full color display. The monochrome display or grayscale display using the first pixel is suitable for displaying information that does not require color display, such as document information.

(Embodiment 2)
In this embodiment, a structure of a CAC (Cloud-Aligned Composite) -OS that can be used for the transistor disclosed in one embodiment of the present invention will be described.

The CAC-OS is one structure of a material in which elements forming a metal oxide are unevenly distributed with a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. In the following, in the metal oxide, one or more metal elements are unevenly distributed, and the region having the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. The state mixed with is also referred to as a mosaic or patch.

Note that the metal oxide preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition to them, element M (M is gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium. Tantalum, tungsten, or magnesium).

For example, an In-M-Zn oxide having a CAC-OS structure is an indium oxide (hereinafter referred to as InO _X1 (X1 is a real number greater than 0)) or indium zinc oxide (hereinafter referred to as In _X2 Zn _Y2 O _Z2 and (X2, Y2, and Z2 is larger real than 0) and.), oxides of the elements M _{(hereinafter, MO} X3 (X3 is greater real than 0) and.), or The element M is a zinc oxide (hereinafter referred to as M _X4 Zn _Y4 O _Z4 (X4, Y4, and Z4 are real numbers greater than 0)) and the like, and the mosaic becomes like a mosaic. InO _X1 or In _X2 Zn _Y2 O _Z2 is distributed in the film (hereinafter also referred to as a cloud shape).

In other words, an In-M-Zn oxide having a CAC-OS structure includes a region in which MO _X3 is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component. Metal oxide. Therefore, the metal oxide may be described as a composite metal oxide. Note that in this specification, for example, the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.

Note that a metal oxide having a CAC-OS structure does not include a stacked structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.

Specifically, a CAC-OS in an In—Ga—Zn oxide (an In—Ga—Zn oxide among CAC-OSs may be specifically referred to as a CAC-IGZO) will be described. The CAC-OS in the In—Ga—Zn oxide is InO _X1 or In _X2 Zn _Y2 O _Z2 and gallium oxide (hereinafter referred to as GaO _X5 (X5 is a real number greater than 0)) or gallium zinc. Oxide (hereinafter referred to as Ga _X6 Zn _Y6 O _Z6 (X6, Y6, and Z6 are real numbers greater than 0)) and the like are separated into a mosaic shape to form mosaic-like InO _X1 , or In _X2 Zn _Y2 O _Z2 is a cloud-like metal oxide.

That is, the CAC-OS in the In—Ga—Zn oxide has a structure in which a region containing GaO _X5 as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component are mixed. A composite metal oxide. Further, a region _{GaO X5} is the main _component, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

Note that IGZO is a common name and may refer to one compound of In, Ga, Zn, and O. As a typical example, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (−1 ≦ x0 ≦ 1, m0 is an arbitrary number) A crystalline compound may be mentioned.

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a layered crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.

In this specification and the like, CAC-IGZO means that a metal oxide containing In, Ga, Zn, and O includes a plurality of regions containing Ga as a main component and a plurality of regions containing In as a main component. Each can be defined as a metal oxide that is randomly dispersed in a mosaic pattern.

The crystallinity of the CAC-OS in the In—Ga—Zn oxide can be evaluated by electron diffraction. For example, in the electron diffraction pattern image, a region having a high luminance in a ring shape is observed. In addition, a plurality of spots may be observed in the ring-shaped region.

The CAC-OS in the In—Ga—Zn oxide has a structure different from that of the IGZO compound in which the metal element is uniformly distributed and has properties different from those of the IGZO compound. That is, the CAC-OS in the In—Ga—Zn oxide is separated into a region containing GaO _X5 or the like as a main component and a region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component. The region whose main component is an element has a mosaic structure.

Instead of gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium When included, the CAC-OS includes a region observed in a part of a nanoparticle mainly including the metal element and a region observed in a part of a nanoparticle mainly including In. However, it means a configuration in which each is randomly distributed in a mosaic shape.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is a region having higher conductivity than a region containing GaO _X5 or the like as a main component. In other words, conductivity is developed when carriers flow through a region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 . Accordingly, a region where In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is distributed in a cloud shape in the metal oxide, so that high field-effect mobility (μ) can be realized.

On the other hand, areas such as _{GaO X5} is the main _component, as compared to the In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component area, it is highly regions insulating. That is, since the region mainly composed of GaO _X5 or the like is distributed in the metal oxide, the leakage current can be suppressed and a good switching operation can be realized.

Therefore, in the case where a CAC-OS in an In—Ga—Zn oxide is used for a semiconductor element, the insulating property caused by GaO _{X5 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 are complementary. Thus, a high on-state current (I _on ), a high field-effect mobility (μ), and a low off-state current (I _off ) can be realized.

A semiconductor element using a CAC-OS in an In—Ga—Zn oxide has high reliability. Therefore, the CAC-OS in the In—Ga—Zn oxide is optimal for various semiconductor devices including a display.

This embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 3)
In this embodiment, a display module and an electronic device of one embodiment of the present invention will be described.

A display module 8000 illustrated in FIG. 16 includes a touch panel 8004 connected to the FPC 8003, a display panel 8006 connected to the FPC 8005, a frame 8009, a printed board 8010, and a battery 8011 between an upper cover 8001 and a lower cover 8002. .

For example, a display device manufactured using the peeling method of one embodiment of the present invention can be used for the display panel 8006. Thereby, a display module can be manufactured with a high yield.

The shapes and dimensions of the upper cover 8001 and the lower cover 8002 can be changed as appropriate in accordance with the sizes of the touch panel 8004 and the display panel 8006.

As the touch panel 8004, a resistive film type or capacitive type touch panel can be used by being overlapped with the display panel 8006. Alternatively, the touch panel 8004 may be omitted, and the display panel 8006 may have a touch panel function.

The frame 8009 has a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed board 8010 in addition to a protective function of the display panel 8006. The frame 8009 may have a function as a heat sink.

The printed board 8010 includes a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. As a power supply for supplying power to the power supply circuit, an external commercial power supply may be used, or a power supply using a battery 8011 provided separately may be used. The battery 8011 can be omitted when a commercial power source is used.

The display module 8000 may be additionally provided with a member such as a polarizing plate, a retardation plate, or a prism sheet.

According to one embodiment of the present invention, a highly reliable electronic device having a curved surface can be manufactured. Further, according to one embodiment of the present invention, an electronic device having flexibility and high reliability can be manufactured.

Electronic devices include, for example, television devices, desktop or notebook personal computers, monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, audio devices Large game machines such as playback devices and pachinko machines are listed.

In addition, the display device of one embodiment of the present invention can achieve high visibility regardless of the intensity of external light. Therefore, it can be suitably used for a portable electronic device, a wearable electronic device (wearable device), an electronic book terminal, and the like.

A portable information terminal 800 illustrated in FIGS. 17A and 17B includes a housing 801, a housing 802, a display portion 803, a display portion 804, a hinge portion 805, and the like.

The housing 801 and the housing 802 are connected by a hinge portion 805. The portable information terminal 800 can be developed from the folded state (FIG. 17A) as shown in FIG.

A display device manufactured using the peeling method of one embodiment of the present invention can be used for at least one of the display portion 803 and the display portion 804. Thereby, a portable information terminal can be manufactured with a high yield.

Each of the display unit 803 and the display unit 804 can display at least one of document information, a still image, a moving image, and the like. When displaying document information on the display unit, the portable information terminal 800 can be used as an electronic book terminal.

Since the portable information terminal 800 can be folded, it has high portability and excellent versatility.

The housing 801 and the housing 802 may include a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

A portable information terminal 810 illustrated in FIG. 17C includes a housing 811, a display portion 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, a camera 817, and the like.

A display device manufactured using the peeling method of one embodiment of the present invention can be used for the display portion 812. Thereby, a portable information terminal can be manufactured with a high yield.

The portable information terminal 810 includes a touch sensor in the display unit 812. Any operation such as making a call or inputting characters can be performed by touching the display portion 812 with a finger or a stylus.

In addition, by operating the operation button 813, the power can be turned on and off, and the type of image displayed on the display portion 812 can be switched. For example, the mail creation screen can be switched to the main menu screen.

Further, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 810, the orientation (portrait or landscape) of the portable information terminal 810 is determined, and the screen display orientation of the display unit 812 is changed. It can be switched automatically. The screen display orientation can also be switched by touching the display portion 812, operating the operation buttons 813, or inputting voice using the microphone 816.

The portable information terminal 810 has one or more functions selected from, for example, a telephone, a notebook, an information browsing device, or the like. Specifically, it can be used as a smartphone. The portable information terminal 810 can execute various applications such as mobile phone, electronic mail, text browsing and creation, music playback, video playback, Internet communication, and games.

A camera 820 illustrated in FIG. 17D includes a housing 821, a display portion 822, operation buttons 823, a shutter button 824, and the like. A removable lens 826 is attached to the camera 820.

A display device manufactured using the peeling method of one embodiment of the present invention can be used for the display portion 822. Thereby, a camera can be manufactured with a high yield.

Here, the camera 820 is configured such that the lens 826 can be removed from the housing 821 and replaced, but the lens 826 and the housing 821 may be integrated.

The camera 820 can capture a still image or a moving image by pressing the shutter button 824. In addition, the display portion 822 has a function as a touch panel and can capture an image by touching the display portion 822.

The camera 820 can be separately attached with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in the housing 821.

18A to 18E are diagrams illustrating electronic devices. These electronic devices include a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, and a sensor 9007 (force, displacement, position, velocity, acceleration, angular velocity, Includes functions to measure rotation speed, distance, light, liquid, magnetism, temperature, chemical, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared ), A microphone 9008 and the like.

A display device manufactured using the peeling method of one embodiment of the present invention can be favorably used for the display portion 9001. Thereby, an electronic device can be manufactured with a high yield.

The electronic devices illustrated in FIGS. 18A to 18E can have various functions. For example, a function for displaying various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a function for displaying a calendar, date or time, a function for controlling processing by various software (programs), Wireless communication function, function for connecting to various computer networks using the wireless communication function, function for transmitting or receiving various data using the wireless communication function, and reading and displaying the program or data recorded on the recording medium It can have a function of displaying on the section. Note that the functions of the electronic devices illustrated in FIGS. 18A to 18E are not limited to these, and may have other functions.

18A is a perspective view illustrating a wristwatch-type portable information terminal 9200, and FIG. 18B is a perspective view illustrating a wristwatch-type portable information terminal 9201.

A portable information terminal 9200 illustrated in FIG. 18A can execute various applications such as a mobile phone, electronic mail, text browsing and creation, music playback, Internet communication, and computer games. Further, the display portion 9001 is provided with a curved display surface, and can perform display along the curved display surface. In addition, the portable information terminal 9200 can execute short-range wireless communication with a communication standard. For example, it is possible to talk hands-free by communicating with a headset capable of wireless communication. In addition, the portable information terminal 9200 includes a connection terminal 9006 and can directly exchange data with other information terminals via a connector. Charging can also be performed through the connection terminal 9006. Note that the charging operation may be performed by wireless power feeding without using the connection terminal 9006.

A mobile information terminal 9201 illustrated in FIG. 18B is different from the mobile information terminal illustrated in FIG. 18A in that the display surface of the display portion 9001 is not curved. Further, the external shape of the display portion of the portable information terminal 9201 is a non-rectangular shape (a circular shape in FIG. 18B).

18C to 18E are perspective views showing a foldable portable information terminal 9202. FIG. Note that FIG. 18C is a perspective view of a state in which the portable information terminal 9202 is expanded, and FIG. 18D is a state in which the portable information terminal 9202 is expanded or changed from one of the folded state to the other. FIG. 18E is a perspective view of the portable information terminal 9202 folded.

The portable information terminal 9202 is excellent in portability in the folded state, and in the expanded state, the portable information terminal 9202 is excellent in display listability due to a seamless wide display area. A display portion 9001 included in the portable information terminal 9202 is supported by three housings 9000 connected by a hinge 9055. By bending between the two housings 9000 via the hinge 9055, the portable information terminal 9202 can be reversibly deformed from the expanded state to the folded state. For example, the portable information terminal 9202 can be bent with a curvature radius of 1 mm to 150 mm.

This embodiment can be combined with any of the other embodiments as appropriate.

In this example, a method of forming a release layer by forming a polyimide thin film on a glass substrate and then irradiating a laser from the glass substrate side after adhering the release film to the polyimide will be described. An appropriate amount of a soluble polyimide solution (product number: SO0100001 at Tochigi Works) was dropped on a glass substrate, and a film was formed by spin coating. After film formation, the substrate was baked at 400 ° C. for 1 hour, and the release film was bonded after baking. As an adhesion method, an adhesive (manufactured by Nissin Resin, CEP05) is applied linearly on polyimide, a PET film (Panac Co., Ltd., CT100 / Lumirror 125UF83) 125 μm is placed as a peeling film, and then stretched with a laminator for adhesion. I let you. Next, an excimer laser (wavelength: 308 nm) was irradiated from the glass substrate side so as to have an energy density of 439 (mJ / cm ² ). After irradiation, the release layer was separated from the glass substrate by making a notch in the release film.

LC / MS analysis was performed on the surface of the glass substrate and the surface of the release film on the release film side of the release film having the separated peelable layer and the peeled glass substrate. A peeling film having a peelable layer to be analyzed, a glass substrate after separating the peelable layer is cut into an arbitrary size, a surface on which the peelable layer of the glass substrate is formed, and a peeling having the peelable layer The surface of the film peeled layer was washed three times using 15 drops of a solution in which acetonitrile and chloroform were mixed at a volume ratio of 7 to 3, and the resulting cleaning solution was used as a measurement sample. As a solvent used for washing, a solution in which acetonitrile and 1,1,1,3,3,3-hexafluoro-2-propanol (abbreviation: HFIP) were mixed at a volume ratio of 7 to 3 was also used. As a reference, the release film (PET \ CEP05) and the glass substrate were similarly washed with the two kinds of mixed solvents to prepare a reference sample.

LC / MS analysis was performed on the two types of samples and the two types of reference samples prepared as described above. In LC / MS analysis, LC (liquid chromatography) separation was performed by Acquity UPLC manufactured by Waters, and MS analysis (mass spectrometry) was performed by Xevo G2 Tof MS manufactured by Waters. The column used for the LC separation was Acquity UPLC BEH C8 (2.1 × 100 mm 1.7 μm), and the column temperature was 40 ° C. As the mobile phase, mobile phase A was acetonitrile and mobile phase B was 0.1% formic acid aqueous solution. The sample injection volume was 5.0 μL.

  For the LC separation, a gradient method for changing the composition of the mobile phase is used. From the start of measurement to 0 to 1 minute, the mobile phase A: mobile phase B = 30: 70, then the composition is changed, and the mobile phase A at 9 minutes is changed. And mobile phase B were linearly gradient so that the ratio of mobile phase A: mobile phase B = 95: 5, and then held at the same rate until 15 minutes.

  In the MS analysis, ionization by electrospray ionization (abbreviation: ESI) was performed, the capillary voltage was 3.01075 kV, the sample cone voltage was 30 V, and the detection was performed in positive and negative modes. The mass range to be measured was m / z = 100 to 1200. FIG. 19 shows a chromatograph of a PDA (photodiode array) detector obtained by the LC / MS analysis performed as described above. The area ratios of the peaks detected in FIG. 19 are summarized in Table 1. Table 1 shows only the mass charge cost detected in the negative mode because no ions were detected in the positive mode.

As can be seen from Table 1, a large number (5 or more, preferably 10 or more) of substances derived from ions having a mass-to-charge ratio of 300 or more and 950 or less were detected from the separation interface of the release layer in a plurality of LC / MS measurements. This substance is generated by decomposition of the release layer polyimide by absorbing the laser.

FIG. 20 shows the absorptance of the laser light when the polyimide film formed in the same manner as in the above experiment is similarly irradiated with laser light having a wavelength of around 308 nm. It can be seen that the polyimide film exhibits an absorptance of 94.3% under the above conditions and absorbs most of the irradiated laser light. That is, by absorbing the irradiated laser light, the polyimide film is decomposed, and it is considered that many substances derived from ions having a mass-to-charge ratio of 300 to 950 are detected in LC / MS measurement. It is done.

Here, the LC / MS analysis of the low molecular weight component contained in the solution of the soluble polyimide used (product number: SO0100001 at Tochigi Works) will be described. When the soluble polyimide solution and chloroform were mixed at a volume ratio of 1: 1, the deposition of polyimide was confirmed. The sample was allowed to stand for 1 hour until the polyimide precipitated, and the obtained supernatant and acetonitrile were diluted to a volume ratio of 10: 1 to obtain Comparative Sample 1.

Similarly, a sample prepared using 1,1,1,3,3,3-hexafluoro-2-propanol (abbreviation: HFIP) instead of chloroform was used as Comparative Sample 2.

LC / MS analysis was performed on the two comparative samples prepared as described above. The apparatus and analysis conditions used for the LC / MS analysis are the same as those when the release layer surface was analyzed.

A chromatograph of a PDA (photodiode array) detector obtained by LC / MS analysis is shown in FIG. FIG. 21A shows the result of the comparative sample 1 and FIG. 21B shows the result of the comparative sample 2. As can be seen from FIGS. 21A and 21B, nothing was detected from the PDA chromatograph. On the other hand, some ions were detected by MS detector. The detected mass-to-charge ratio and retention time are summarized in Table 2. Table 2 shows only the mass charge cost detected in the negative mode because no ions were detected in the positive mode.

As can be seen from Table 2, it was confirmed that the soluble polyimide solution contained several kinds of low molecular weight components dissolved in chloroform and HFIP to such an extent that they could be detected by MS.

When this comparative sample was compared with the peeled sample, the low molecular weight component having a mass to charge ratio (m / z) of 300 or more and 950 or less detected in the peeled sample was contained in the soluble polyimide solution. It was confirmed that it was not caused by the peeling process. Since the low molecular weight component produced in the peeling process is present at the peeling interface, it is considered that good peelability was obtained with the generation of the low molecular weight component notched.

Therefore, when these substances are generated, the portion becomes brittle, and peeling occurs at the brittle portion as a notch. It can be said that the peeling method of the present invention, in which an embrittlement layer is derived from a deteriorated polyimide, can be provided with a peeling site when it is desired to peel off, and thus is a very excellent peeling method in the substrate preparation process. In other words, the layer to be peeled can be held on the substrate in a process that should not be peeled off. Therefore, a substrate manufactured using the peeling method of the present invention has a low cost, a short tact time, and a highly reliable layer to be peeled.

10A Display device 10B Display device 13 Adhesive layer 14 Fabrication substrate 21 Peeled layer 22 Substrate 23 Peel layer 24 Resin layer 25 Separation region 28 Adhesive layer 29 Substrate 31 Insulating layer 32 Insulating layer 33 Insulating layer 34 Insulating layer 35 Insulating layer 40 Transistor 41 Conductive layer 43a Conductive layer 43b Conductive layer 43c Conductive layer 44 Metal oxide layer 45 Conductive layer 49 Transistor 60 Light emitting element 61 Conductive layer 62 EL layer 63 Conductive layer 64 Break 65 Instrument 66 Laser light 67 Irradiation region 74 Insulating layer 75 Protective layer 75a Substrate 75b Adhesive layer 76 Connector 80 Transistor 81 Conductive layer 82 Insulating layer 83 Metal oxide layer 84 Insulating layer 85 Conductive layer 86a Conductive layer 86b Conductive layer 86c Conductive layer 91 Fabrication substrate 93 Release layer 94 Separation region 95 Insulating layer 96 Partition 97 Colored layer 98 Light-shielding layer 99 Adhesive layer 372 FPC
381 Display unit 382 Drive circuit unit 800 Portable information terminal 801 Case 802 Case 803 Display unit 804 Display unit 805 Hinge unit 810 Mobile information terminal 811 Case 812 Display unit 813 Operation button 814 External connection port 815 Speaker 816 Microphone 817 Camera 820 Camera 821 Housing 822 Display unit 823 Operation button 824 Shutter button 826 Lens 8000 Display module 8001 Upper cover 8002 Lower cover 8003 FPC
8004 Touch panel 8005 FPC
8006 Display panel 8009 Frame 8010 Printed circuit board 8011 Battery 9000 Housing 9001 Display unit 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9055 Hinge 9200 Portable information terminal 9201 Portable information terminal 9202 Portable information terminal

Claims (14)

A substrate,
A first resin layer formed in contact with the substrate;
A second resin layer formed in contact with the first resin layer;
A first layer formed in contact with the second resin layer,
The second resin layer is composed mainly of a polyimide resin,
An element in which a substance having a mass to charge ratio of 300 or more and 950 or less is detected at an interface between the first resin layer and the second resin layer in a mass-to-charge ratio in LC-MS measurement. 2. The element according to claim 1, wherein five or more substances of 300 to 950 are detected in the mass-to-charge ratio in the LC-MS measurement. 2. The element according to claim 1, wherein 10 or more substances of 300 to 950 are detected in the mass-to-charge ratio in the LC-MS measurement. 4. The element according to claim 1, wherein the substrate has flexibility. 5. The semiconductor device according to claim 1, wherein a transistor is formed in the first layer. 6. The semiconductor device according to claim 5, wherein the transistor includes a metal oxide in a channel formation region. The display device according to claim 1, wherein a display element is formed in the first layer. On the manufacturing substrate, a first resin layer mainly composed of polyimide is formed,
Forming a peelable layer on the first resin layer;
By irradiating the first resin layer with laser light, a separation region containing a substance having a mass to charge ratio of 300 or more and 950 or less in the LC-MS measurement is formed inside the first resin layer,
A peeling method in which the manufacturing substrate and the layer to be peeled are separated in the separation region. On the manufacturing substrate, a first resin layer mainly composed of polyimide is formed,
Forming a layer to be peeled including a transistor over the first resin layer;
By irradiating the first resin layer with laser light, a separation region containing a substance having a mass to charge ratio of 300 or more and 950 or less in the LC-MS measurement is formed inside the first resin layer,
A peeling method in which the manufacturing substrate and the layer to be peeled are separated in the separation region. The method for manufacturing a semiconductor device according to claim 9, wherein the transistor includes a metal oxide in a channel formation region. 11. The peeling method according to claim 8, further comprising: a separation region including five or more substances of 300 to 950 in the mass-to-charge ratio in the LC-MS measurement. 11. The peeling method according to claim 8, further comprising: a separation region including 10 or more substances of 300 to 950 in the mass-to-charge ratio in the LC-MS measurement. In any one of Claims 8 to 12,
A method for manufacturing a display device, in which the layer to be peeled includes a display element. In any one of Claims 8 to 12,
A method for manufacturing a display device, in which the peel-off layer includes a light-emitting element.