JP2004165679A - Transfer method for thin-film device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conform the lamination relation of a transferred layer to a substrate used when manufacturing the transferred layer including a thin-film device with the relation of the transferred layer to a transfer destination to which the transferred layer is transferred. <P>SOLUTION: A first isolation layer is set up on a substrate, and a thin-film device 140 such as a TFT and the like is formed on that substrate. After the thin-film device 140 is formed, the thin-film device 140 is joined to a primary transfer destination 180 via a second isolation layer 160 composed of water soluble adhesive, organic solvent soluble adhesive, or adhesive that has a stripping action through heating or ultraviolet irradiation, and then, a laser beam is projected from the back of the substrate. This causes a stripping at the first isolation layer which releases the thin-film device 140 from the substrate. Further, an adhesive layer 190 is used at the bottom surface of the thin-film device 140 to join it to a secondary transfer destination 200. After that, the primary transfer destination 180 is removed at the secondary isolation layer 160 as a boundary. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a method for transferring a thin film device.

  For example, when manufacturing a liquid crystal display using a thin film transistor (TFT), a process of forming a thin film transistor on a substrate by CVD or the like is performed. Since the process of forming a thin film transistor on a substrate involves high-temperature treatment, the substrate needs to be made of a material having excellent heat resistance, that is, a material having a high softening point and a high melting point. Therefore, at present, quartz glass is used as a substrate that can withstand a temperature of about 1000 ° C., and heat-resistant glass is used as a substrate that can withstand a temperature of about 500 ° C.

  As described above, the substrate on which the thin film devices are mounted must satisfy the conditions for manufacturing the thin film devices. That is, the substrate to be used is determined so as to always satisfy the manufacturing conditions of the mounted device.

  However, focusing only on the stage after a substrate on which a thin film device such as a TFT is mounted, the above-mentioned “substrate” is not necessarily preferred. For example, as described above, when a manufacturing process involving high-temperature processing is performed, quartz is used. Substrates, heat-resistant glass substrates, and the like are used, but these are very expensive, and thus increase the product price.

  Further, the glass substrate is heavy and has a property of being easily broken. Liquid crystal displays used in portable electronic devices such as palmtop computers and mobile phones are desirably as inexpensive as possible, lightweight, resistant to some deformation, and hard to break when dropped. Generally, glass substrates are heavy, vulnerable to deformation, and may be broken by falling.

  In other words, there is a groove between the constraint due to the manufacturing conditions and the preferable characteristics required for the product, and it has been extremely difficult to satisfy both conditions and characteristics.

  Therefore, the present applicant has proposed a technique in which a thin film device is formed on a first substrate by a conventional process, and then the thin film device is separated from the first substrate and transferred to a second substrate. . For this purpose, a separation layer is formed between the first substrate and the thin film device that is the layer to be transferred. By irradiating the separation layer with, for example, light, the thin film device which is the layer to be transferred is separated from the first substrate, and the layer to be transferred is transferred to the second substrate side.

  According to experiments performed by the present inventor, it has been found that, when a thin film device is peeled off from the first substrate, merely irradiating the separation layer with light, for example, may not sufficiently cause a peeling phenomenon in the separation layer. .

  According to the inventor's intensive studies, it has been found that whether or not this peeling phenomenon easily occurs depends on the properties of the separation layer.

  Furthermore, the stacking relation of the transfer layer to the first substrate used when manufacturing the transfer layer and the stack relation of the transfer layer to the second substrate to which the transfer layer is transferred are different from each other. There was a problem of getting it.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film capable of matching the lamination relationship of a transfer layer to a substrate used in the production of the transfer layer and the lamination relationship of the transfer layer to a transfer body to which the transfer layer is transferred. An object of the present invention is to provide a device transfer method.

  Another object of the present invention is to make it possible to easily peel a thin film device from a substrate before a step of causing a peeling phenomenon in peeling of a separation layer, by compensating that the separation layer is easily peeled. An object of the present invention is to provide a method for transferring a thin film device.

The present invention can utilize the following thin film device peeling method, namely,
A first step of forming a separation layer on the substrate;
A second step of forming a thin film device on the separation layer;
A third step of causing a separation phenomenon in the layer and / or at the interface of the separation layer to separate the substrate from the separation layer;
In the method of stripping a thin film device having
Before the third step, an ion implantation step of implanting ions into the separation layer can be provided.

  For example, a separation layer having a property of absorbing light is provided on a substrate such as a quartz substrate having high reliability in device manufacturing, and a thin film device such as a TFT is formed on the substrate. Preferably, the thin film device is then bonded to a desired transfer body, for example, via an adhesive layer. Thereafter, the separation layer is irradiated with light, for example, to cause a separation phenomenon in the separation layer. Thus, for example, by applying a force to the substrate, the thin film device can be peeled from the substrate.

  At this time, by implanting ions into the separation layer before the separation step, the separation layer in the separation step becomes remarkable, and the thin film device can be surely separated from the substrate.

  Here, by injecting ions into the separation layer in advance, the action defined below is performed, and the separation layer separation phenomenon becomes remarkable.

  The three steps may include a step of gasifying the ions implanted into the separation layer. When the ions in the separation layer are gasified, an internal pressure is generated in the separation layer, and the separation phenomenon is promoted.

  In this case, the separation layer is irradiated with light, and the light can gasify the separation ions. At this time, when light is irradiated from the back side of the substrate, the amount of light incident on the thin film device layer can be reduced, and deterioration of the characteristics can be prevented.

  In the ion implantation step, the bonds of atoms or molecules constituting the separation layer are cut by the ions, so that the separation layer can be damaged in advance. Therefore, the separation phenomenon in the separation layer which occurs in the subsequent separation step is promoted.

  In the ion implantation step, the characteristics of the separation layer may be changed by the ions to weaken the adhesion between the separation layer and the substrate in advance. Therefore, the separation phenomenon in the separation layer which occurs in the subsequent separation step is promoted.

The second step includes a thin film transistor forming step for forming a thin film transistor,
The thin film transistor forming step includes a channel layer forming step,
The ion implantation step may be performed after the channel layer forming step.

  The channel forming step is a high-temperature processing step as compared with other steps. Therefore, if ions for promoting the separation phenomenon are implanted into the separation layer before that, there is a risk that the ions will be released from the separation layer during the subsequent high-temperature treatment.

The thin film transistor forming step includes a channel pattern forming step after the channel layer forming step,
The ion implantation step may be performed after the channel pattern forming step.

  If a channel pattern is formed, the area of the channel pattern itself, which can be an obstacle to the implantation, even if the ions for promoting the separation phenomenon are implanted from the channel pattern side, is reduced. Therefore, the ions can easily reach the separation layer.

  The ion implantation step may be performed by forming a mask on a region of the channel layer that will be a channel region.

  This is because when ions are implanted into the channel region, transistor characteristics may be deteriorated. The step of implanting ions while masking the channel region may be performed before or after forming the channel pattern.

The thin film transistor forming step, after the channel pattern forming step, a step of forming a gate insulating film on the channel pattern, and a step of forming a gate electrode on the gate insulating film,
The ion implantation step can be performed using the gate electrode as a mask.

  Since the gate electrode is formed at a position facing the channel, the gate electrode can also be used as a mask for preventing ions from being implanted into the channel region into the channel region. Note that a mask may be further formed on the gate electrode according to the ion acceleration voltage.

  In the ion implantation step, an impurity ion implanted into at least one of a source region and a drain region in the channel pattern and the ion implanted into the separation layer with a lighter mass can be simultaneously implanted.

  This makes it possible to use both the step of implanting ions into the separation layer and the step of implanting impurity ions into the source and / or drain regions. Note that ions are lighter in mass than impurity ions, and thus can reach a separation layer located deeper than the source and drain regions.

The thin film transistor forming step includes a step of forming an amorphous silicon layer as the channel layer, and then a crystallization step of laser annealing and crystallizing the amorphous silicon layer,
The ion implantation process may be performed before the crystallization process.

  Even if the channel layer is damaged by the ion implantation process, the crystallinity can be improved by the subsequent laser annealing process.

  The ions can be hydrogen ions.

  When the hydrogen ions are implanted into the separation layer, they can contribute to the above-described operation. In particular, hydrogen ions have a smaller mass than impurity ions (boron, phosphorus, and the like) implanted into the source and the drain, and thus are suitable for simultaneous implantation of impurities into the source and the drain. In addition, as ions that mainly cause gasification, nitrogen ions and the like can be given in addition to hydrogen ions. In addition, as ions that mainly cause damage or decrease in adhesion, Si ions and the like can be given in addition to hydrogen ions.

  A process temperature of a step performed after the ion implantation step may be less than 350 ° C.

  Since the hydrogen injected into the separation layer starts to be released by being heated to 350 ° C. or higher, the step requiring a process temperature of 350 ° C. or higher is preferably performed before the step of ion implantation into the separation layer.

  A thin film device peeled from the substrate by the above-described peeling method can be easily peeled from the separation layer, so that a mechanical pressure acting upon peeling is small, and a defect depending on the magnitude of the load is required. Can be reduced.

  An active matrix substrate in which a pixel portion includes a thin film transistor arranged in a matrix and a pixel electrode connected to one end of the thin film transistor, and the thin film transistor of the pixel portion is transferred using the above-described peeling method. By doing so, an active matrix substrate can be manufactured.

  This active matrix substrate can also reduce defects. A liquid crystal display device can be manufactured using this active matrix substrate. Since this liquid crystal display device uses an active matrix substrate with few defects, the defects of the liquid crystal display device as a whole are also reduced.

A method for transferring a thin film device according to one embodiment of the present invention includes a first step of forming a first separation layer on a substrate;
A second step of forming a transferred layer including a thin film device on the first separation layer;
A third step of forming a second separation layer made of a water-soluble or organic solvent-soluble adhesive on the transferred layer,
A fourth step of bonding a primary transfer member on the second separation layer;
A fifth step of removing the substrate from the transferred layer, bordering on the first separation layer;
A sixth step of bonding a secondary transfer body to the lower surface of the transfer-receiving layer;
A seventh step of contacting the second separation layer with water or an organic solvent, and removing the primary transfer body from the transfer-receiving layer, bordering on the second separation layer;
And transferring the transferred layer including the thin-film device to a secondary transfer member.

  According to one embodiment of the present invention, the first transfer layer is removed from the lower surface of the transfer-receiving layer, and the secondary transfer member is bonded to the lower surface thereof. Separated from the layer. In this case, the secondary transfer member exists at the place where the original substrate was located with respect to the transfer target layer, and the stacking relationship of the transfer target layer with respect to the original substrate and the transfer target relative to the secondary transfer member are determined. The stacking relationship of the layers matches. Here, since a water-soluble adhesive or an organic solvent-soluble adhesive is used as the second separation layer, it is only necessary to bring the second separation layer into contact with water or an organic solvent in order to release the primary transfer member.

  In the method for transferring a thin film device according to another aspect of the present invention, an adhesive which can be peeled off by heating or ultraviolet rays is used as the second separation layer in the above transfer method invention instead of the above adhesive.

  In this case, if the second separation layer is brought into contact with an adhesive which can be peeled off by heating or ultraviolet rays to release the primary transfer member, the stacking relation of the transfer target layer to the initial substrate and the The lamination relationship of the transfer receiving layer to the next transfer body can be matched.

  Next, embodiments of the present invention will be described with reference to the drawings.

<First embodiment>
1 to 6 are diagrams for explaining a method of transferring a thin-film device, which is a premise of the present invention.

[Step 1]
As shown in FIG. 1, a separation layer (light absorption layer) 120 is formed on a substrate 100.

  Hereinafter, the substrate 100 and the separation layer 120 will be described.

(1) Description of Substrate 100 As the substrate 100, a substrate having a light-transmitting property through which light can be transmitted is used.

  In this case, the light transmittance is preferably 10% or more, more preferably 50% or more. If the transmittance is too low, the attenuation (loss) of light increases, and a larger amount of light is required to separate the separation layer 120.

  In addition, the substrate 100 is preferably made of a highly reliable material, and particularly preferably made of a material having excellent heat resistance. The reason is that, for example, when a transfer layer 140 and an intermediate layer 142 described later are formed, the process temperature may be high (for example, about 350 to 1000 ° C.) depending on the type and the formation method. This is because if the substrate 100 is excellent in heat resistance, the range of setting of film forming conditions such as temperature conditions in forming the transfer layer 140 and the like on the substrate 100 is widened.

  Therefore, it is preferable that the substrate 100 be made of a material whose strain point is equal to or higher than Tmax when the maximum temperature at the time of forming the transfer layer 140 is Tmax. Specifically, the constituent material of the substrate 100 preferably has a strain point of 350 ° C. or higher, more preferably 500 ° C. or higher. Examples of such a material include heat-resistant glass such as quartz glass, Corning 7059, and NEC Glass OA-2.

  Further, the thickness of the substrate 100 is not particularly limited, but is usually preferably about 0.1 to 5.0 mm, and more preferably about 0.5 to 1.5 mm. If the thickness of the substrate 100 is too small, the strength is reduced. If the thickness is too large, light is easily attenuated when the transmittance of the substrate 100 is low. When the light transmittance of the substrate 100 is high, the thickness may exceed the upper limit. Note that the thickness of the substrate 100 is preferably uniform so that light can be uniformly emitted.

(2) Description of Separation Layer 120 The separation layer 120 is formed by one of a physical action (light, heat, etc.), a chemical action (chemical reaction with a chemical solution, etc.) or a mechanical action (tensile force, vibration, etc.). By receiving one or more actions, the bonding force is reduced or eliminated, thereby promoting the separation of the substrate 100 via the separation layer 120.

  As the separation layer 120, for example, a material having a property of absorbing irradiated light and causing separation in the layer and / or at the interface (hereinafter, referred to as “interlayer separation” or “interface separation”) may be used. be able to. Preferably, the irradiation of light causes the bonding force between atoms or molecules of the substance forming the separation layer 120 to disappear or decrease, that is, ablation occurs to cause intra-layer peeling and / or interfacial peeling. .

  Further, gas may be released from the separation layer 120 by light irradiation, and a separation effect may be exhibited. That is, there is a case where the component contained in the separation layer 120 is released as a gas and a case where the separation layer 120 absorbs light and becomes a gas for a moment and the vapor is released to contribute to separation. .

  The present invention is characterized in that after formation of the separation layer 120 having such characteristics, ions for promoting separation are implanted into the separation layer 120, whereby the separation phenomenon in the separation layer 120 in a subsequent step is reduced. To promote it. Therefore, any kind of peeling promoting ion can be used as long as it promotes the peeling phenomenon due to the above-mentioned physical action, chemical action or mechanical action.

  Next, examples of the composition of the separation layer 120 include those described in the following AE.

A. Amorphous silicon (a-Si)
This amorphous silicon may contain hydrogen (H). In this case, the content of H is preferably about 2 atomic% or more, and more preferably about 2 to 20 atomic%. As described above, when a predetermined amount of hydrogen (H) is contained, hydrogen is released by irradiating light later, and an internal pressure is generated in the separation layer 120, which is a force for separating the upper and lower thin films. Become. The content of hydrogen (H) in the amorphous silicon is adjusted by appropriately setting film forming conditions such as gas composition, gas pressure, gas atmosphere, gas flow rate, temperature, substrate temperature, and input power in CVD. be able to.

  In the present embodiment, in addition to containing hydrogen in the separation layer 120 depending on the process conditions, as described later, hydrogen ions are implanted as exfoliation promoting ions at any time after the formation of the amorphous silicon layer, as described later. be able to. This allows a certain amount or more of hydrogen to be contained in the amorphous silicon layer regardless of the amorphous silicon process conditions.

B. Various oxide ceramics such as silicon oxide or silicate compound, titanium oxide or titanate compound, zirconium oxide or zirconate compound, lanthanum oxide or lanthanum oxide compound, conductive body (ferroelectric substance) or semiconductor. , SiO ₂ , and Si ₃ O _2. Examples of the silicate compound include K ₂ SiO ₃ , Li ₂ SiO ₃ , CaSiO ₃ , ZrSiO ₄ , and Na ₂ SiO ₃ .

Titanium _{oxide, TiO, Ti 2 0 3,} Ti0 2 , and examples of titanate compounds, for _{example, BaTi0 4, BaTiO 3, Ba} 2 Ti 9 O 20, BaTi 5 O 11, CaTiO 3, SrTiO 3, PbTiO ₃ , MgTiO ₃ , ZrTiO ₂ , SnTiO ₄ , Al ₂ TiO ₅ , and FeTiO ₃ are mentioned.

Examples of zirconium oxide include ZrO ₂ , and examples of zirconate compounds include BaZrO ₃ , ZrSiO ₄ , PbZrO ₃ , MgZrO ₃ , and K ₂ ZrO ₃ .

C. Ceramic or dielectric (ferroelectric) such as PZT, PLZT, PLLZT, PBZT
D. B. Nitride ceramics such as silicon nitride, aluminum nitride, titanium nitride, etc. Organic polymer materials Organic polymer materials include -CH-, -CO- (ketone), -CONH- (amide), -NH- (imide), -COO- (ester), -N = N- (azo ), -CH = N- (Shif) and the like (these bonds are broken by irradiation of light), in particular, any compounds having many of these bonds. Further, the organic polymer material may have an aromatic hydrocarbon (one or more benzene rings or a condensed ring thereof) in the constitutional formula.

  Specific examples of such organic polymer materials include polyolefins such as polyethylene and polypropylene, polyimides, polyamides, polyesters, polymethyl methacrylate (PMMA), polyphenylene sulfide (PPS), polyether sulfone (PES), and epoxy resins. Is raised.

F. Metal Examples of the metal include Al, Li, Ti, Mn, In, Sn, Y, La, Ce, Nd, Pr, Gd, and Sm, or an alloy containing at least one of these.

  The thickness of the separation layer 120 varies depending on conditions such as the purpose of peeling and the composition, layer structure, and formation method of the separation layer 120, but is usually preferably about 1 nm to 20 μm, more preferably about 5 nm to 2 μm. More preferably, it is more preferably about 5 nm to 1 μm. If the thickness of the separation layer 120 is too small, the uniformity of the film is impaired, and the separation may be uneven. If the thickness is too large, good separation of the separation layer 120 is ensured. In addition, it is necessary to increase the light power (light amount), and it takes time to remove the separation layer 120 later. Note that the thickness of the separation layer 120 is preferably as uniform as possible.

  The method for forming the separation layer 120 is not particularly limited, and is appropriately selected according to various conditions such as a film composition and a film thickness. For example, various vapor deposition methods such as CVD (including MOCVD, low pressure CVD, and ECR-CVD), vapor deposition, molecular beam deposition (MB), sputtering, ion plating, PVD, electroplating, immersion plating (dipping), Various plating methods such as electroless plating, Langmuir-Projet (LB) method, coating methods such as spin coating, spray coating and roll coating, various printing methods, transfer methods, ink jet methods, powder jet methods, and the like. It can also be formed by combining two or more of the above.

  For example, when the composition of the separation layer 120 is amorphous silicon (a-Si), it is preferable to form the film by CVD, especially low pressure CVD or plasma CVD.

  When the separation layer 120 is made of a ceramic by a sol-gel method or when it is made of an organic polymer material, it is preferable to form the film by a coating method, particularly, spin coating.

[Step 2]
Next, as shown in FIG. 2, a layer to be transferred (thin film device layer) 140 is formed on the separation layer 120. The details of Step 2 and subsequent steps will be described later with reference to FIGS. 8 to 18. In the present embodiment, in the middle of the steps of FIGS. Has been implemented.

An enlarged cross-sectional view of the K portion (the portion surrounded by a dashed line in FIG. 2) of the thin film device layer 140 is shown on the right side of FIG. As illustrated, the thin film device layer 140 includes, for example, a TFT (thin film transistor) formed on an SiO ₂ film (intermediate layer) 142, and the TFT introduces an n-type impurity into a polysilicon layer. A source / drain layer 146, a channel layer 144, a gate insulating film 148, a gate electrode 150, an interlayer insulating film 154, and an electrode 152 made of, for example, aluminum.

In this embodiment, the use of the Si0 ₂ film as an intermediate layer provided in contact with the separation layer 120, it is also possible to use other insulating film such as Si ₃ N _4. The thickness of the Si0 ₂ film (intermediate layer) is appropriately determined in accordance with the degree of its formation purpose and exhibit and can function normally is preferably in the range of about 10 nm to 5 [mu] m, it is about 40nm~1μm of Is more preferred. The intermediate layer is formed for various purposes, for example, a protective layer that physically or chemically protects the transferred layer 140, an insulating layer, a conductive layer, a laser light shielding layer, a barrier layer for preventing migration, and a reflective layer. That exhibit at least one of the functions described above.

In some cases, the transfer layer (thin film device layer) 140 may be formed directly on the separation layer 120 without forming an intermediate layer such as a SiO ₂ film.

  The layer to be transferred 140 (thin film device layer) is a layer including a thin film device such as a TFT as shown on the right side of FIG.

  As the thin film device, in addition to the TFT, for example, a thin film diode, a photoelectric conversion element (photo sensor, solar cell) formed of a PIN junction of silicon, a silicon resistance element, other thin film semiconductor devices, and electrodes (eg, ITO, mesa) Actuators such as transparent electrodes such as films), switching elements, memories, piezoelectric elements, etc., micro mirrors (piezo thin film ceramics), magnetic recording thin film heads, coils, inductors, thin magnetic highly permeable materials and micro magnetic devices combining them, There are filters, reflection films, dichroic mirrors and the like.

  Such thin-film devices are usually formed through relatively high process temperatures, depending on the method of formation. Therefore, in this case, as described above, the substrate 100 needs to have a high reliability that can withstand the process temperature.

[Step 3]
Next, as shown in FIG. 3, the thin film device layer 140 is bonded (adhered) to the transfer body 180 via the adhesive layer 160.

  Preferable examples of the adhesive constituting the adhesive layer 160 include various curable adhesives such as a reaction curable adhesive, a thermosetting adhesive, a light curable adhesive such as an ultraviolet curable adhesive, and an anaerobic curable adhesive. An adhesive may be used. The composition of the adhesive may be, for example, any of epoxy, acrylate, and silicone. The formation of such an adhesive layer 160 is performed by, for example, a coating method.

  In the case of using the curable adhesive, for example, a curable adhesive is applied on the layer to be transferred (thin film device layer) 140 and a transfer body 180 is bonded thereon, and then cured according to the characteristics of the curable adhesive. The curable adhesive is cured by a method, and the transfer receiving layer (thin film device layer) 140 and the transfer body 180 are adhered and fixed.

  When the adhesive is of a photo-curing type, light is irradiated from one outside of the light transmitting substrate 100 or the light transmitting transfer body 180 (or from both outside of the light transmitting substrate and the transfer body). As the adhesive, a photocurable adhesive, such as an ultraviolet curable adhesive, which hardly affects the thin film device layer is preferable.

  As the adhesive layer 160, a water-soluble adhesive can be used. Examples of this type of water-soluble adhesive include Chemi-Seal U-451D (trade name) manufactured by Chemtech Co., Ltd., and Three Bond 3046 (trade name) manufactured by Three Bond Co., Ltd.

  As the adhesive layer 160, an adhesive that is soluble in various organic solvents can be used.

  As the adhesive layer 160, an adhesive exhibiting a peeling action by heating can be used. As this kind of adhesive, for example, Riba Alpha (trade name) manufactured by Nitto Denko can be used.

  As the adhesive layer 160, an adhesive exhibiting a peeling action by ultraviolet irradiation can be used. As this kind of adhesive, for example, dicing tapes D-210 and D-636 for glass and ceramic manufactured by Lintec Corporation can be used.

  It is to be noted that, different from the illustration, an adhesive layer 160 may be formed on the transfer body 180 side, and a transferred layer (thin film device layer) 140 may be bonded thereon. Note that, for example, when the transfer body 180 itself has an adhesive function, the formation of the adhesive layer 160 may be omitted.

  The transfer body 180 is not particularly limited, but includes a substrate (plate material), particularly a transparent substrate. Note that such a substrate may be a flat plate or a curved plate. Further, the transfer body 180 may be inferior to the substrate 100 in properties such as heat resistance and corrosion resistance. The reason is that in the present invention, the transfer layer (thin film device layer) 140 is formed on the substrate 100 side, and then the transfer layer (thin film device layer) 140 is transferred to the transfer body 180. This is because the characteristics to be obtained, especially the heat resistance, do not depend on the temperature conditions or the like when the transfer target layer (thin film device layer) 140 is formed.

  Accordingly, assuming that the maximum temperature at the time of forming the transfer layer 140 is Tmax, a material having a glass transition point (Tg) or a softening point of Tmax or less can be used as a material of the transfer body 180. For example, the transfer body 180 can be formed of a material having a glass transition point (Tg) or softening point of preferably 800 ° C. or lower, more preferably 500 ° C. or lower, and further preferably 320 ° C. or lower.

  The transfer member 180 preferably has a certain degree of rigidity (strength) as the mechanical characteristics, but may have flexibility and elasticity.

  Examples of the constituent material of the transfer body 180 include various synthetic resins and various glass materials. Particularly, various synthetic resins and ordinary (low melting point) inexpensive glass materials are preferable.

  As the synthetic resin, any of a thermoplastic resin and a thermosetting resin may be used. For example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), cyclic polyolefins, modified Polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamide imide, polycarbonate, poly- (4-methylbenten-1), ionomer, acrylic resin, polymethyl methacrylate, acrylic-styrene copolymer (AS Resin), butadiene-styrene copolymer, polio copolymer (EVOH), polyethylene terephthalate (PET), polyester such as polybutylene terephthalate (PBT), precyclohexane terephthalate (PCT), poly Polyester, polyether ketone (PEK), polyether ether ketone (PEEK), polyetherimide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyfluoroethylene Vinylidene chloride, other fluoroplastics, styrene, polyolefin, polyvinyl chloride, polyurethane, fluororubber, chlorinated polyethylene, etc., various thermoplastic elastomers, ethoxy resin, phenol resin, urea resin, melamine resin, Saturated polyesters, silicone resins, polyurethanes, and the like, or copolymers, blends, polymer alloys, and the like containing these as the main component, and one or more of these (for example, two layers) As a laminate of the upper) it can be used.

  Examples of the glass material include silicate glass (quartz glass), alkali silicate glass, soda lime glass, potassium lime glass, lead (alkali) glass, barium glass, borosilicate glass, and the like. Of these, those other than silicate glass have a lower melting point than silicate glass, are relatively easy to mold and process, and are inexpensive, and are therefore preferable.

  When a transfer member 180 made of a synthetic resin is used, the large transfer member 180 can be integrally formed, and even if the transfer member 180 has a complicated shape such as a member having a curved surface or irregularities, it can be easily formed. In addition, various advantages such as low material cost and low manufacturing cost can be enjoyed. Therefore, the use of a synthetic resin is advantageous in manufacturing a large and inexpensive device (for example, a liquid crystal display).

  The transfer body 180 is, for example, a device that constitutes an independent device such as a liquid crystal cell, or a part of the device such as a color filter, an electrode layer, a dielectric layer, an insulating layer, or a semiconductor element. May be constituted.

  Further, the transfer body 180 may be a material such as metal, ceramics, stone, wood paper, or the like, or on any surface constituting a certain product (on a clock, on an air conditioner, on a printed circuit board, etc.). ), Or on the surface of a structure such as a wall, a pillar, a ceiling, or a window glass.

[Step 4]
Next, as shown in FIG. 4, light is irradiated from the back surface side of the substrate 100.

  This light is applied to the separation layer 120 after passing through the substrate 100. Thereby, intra-layer peeling and / or interfacial peeling occur in the separation layer 120, and the bonding force decreases or disappears.

  The principle of the separation within the separation layer 120 and / or the interfacial separation occurring is that ablation occurs in the constituent material of the separation layer 120, the gas contained in the separation layer 120 is released, and the melting that occurs immediately after the irradiation is performed. , Transpiration and the like.

  Here, ablation means that the fixed material (the constituent material of the separation layer 120) that has absorbed the irradiation light is excited photochemically or thermally, and the surface or internal bond of atoms or molecules is cut and released. In other words, mainly, all or a part of the constituent material of the separation layer 120 appears as a phenomenon that causes a phase change such as melting and evaporation (vaporization). In addition, the phase change may result in a small firing state, and the bonding force may be reduced.

  Whether the separation layer 120 causes intra-layer separation, interfacial separation, or both depends on the composition of the separation layer 120 and various other factors, and one of the factors is irradiation. Conditions such as the type of light, wavelength, intensity, and reaching depth are given.

  Here, in the present embodiment, after the formation of the separation layer 120, separation-promoting ions are implanted in the fourth step in order to more surely cause a separation phenomenon in the separation layer 120 itself.

  The separation promoting ions have at least one of the following three actions or a combination of two or more of them and promote the separation phenomenon of the separation layer 120 in the fourth step.

  One of the reasons is that the separation-promoting ions, for example, hydrogen (H) or nitrogen (N) injected into the separation layer 120 are gasified by the execution of the fourth step, thereby promoting the separation of the separation layer 120. .

  The other is to cut off the bonds of the atoms or molecules constituting the separation layer 120 with the separation promoting ions such as hydrogen (H), nitrogen (N) or silicon (Si) in the separation promoting ion implantation step. In this case, the isolation layer 120 is damaged in advance. Therefore, in the separation layer 120 which has been damaged in advance, peeling occurs relatively easily by performing the fourth step.

  Still another is that, in a separation-promoting ion implantation step, the characteristics of the separation layer 120 are changed by the separation-promoting ions, for example, hydrogen (H), nitrogen (N) or silicon (Si). The adhesion to the substrate 100 has been weakened in advance. Also in this case, in the separation layer 120 whose adhesion to the substrate has been weakened, peeling occurs relatively easily by performing the fourth step.

  The light applied in the fourth step may be any light as long as it causes separation within the separation layer 120 and / or interfacial separation, for example, X-rays, ultraviolet rays, visible light, and infrared rays (heat rays). , Laser light, millimeter waves, microwaves, electron beams, radiation (α rays, β rays, γ rays), and the like. Among them, a laser beam is preferable in that the separation layer 120 is easily peeled (ablation).

Examples of a laser device that generates this laser light include various gas lasers and solid-state lasers (semiconductor lasers). Excimer lasers, Nd-YAG lasers, Ar lasers, CO ₂ lasers, CO lasers, He-Ne lasers, and the like are available. Are preferably used, and among them, excimer laser is particularly preferable.

  Since the excimer laser outputs high energy in a short wavelength region, ablation can be caused in the separation layer 120 in an extremely short time, and therefore, the temperature of the adjacent transfer body 180, the substrate 100, and the like hardly increases. That is, the separation layer 120 can be peeled off without causing deterioration or damage.

  In addition, when ablation is caused in the separation layer 120, if there is wavelength dependence of light, it is preferable that the wavelength of the laser light to be applied is about 100 nm to 350 nm.

  FIG. 7 shows an example of the transmittance of the substrate 100 with respect to the wavelength of light. As shown, the transmittance has a characteristic of sharply increasing at a wavelength of 200 nm. In such a case, light having a wavelength of 210 nm or more, for example, Xe-Cl excimer laser light (wavelength 308 nm), KrF laser light (wavelength 248 nm), or the like is irradiated.

  In addition, in the case where separation characteristics are given to the separation layer 120 by causing a phase change such as gas release, vaporization, and sublimation, the wavelength of the irradiated laser beam is preferably about 350 to 1200 nm.

In addition, the energy density of the laser beam irradiated, particularly the energy density in the case of the excimer laser is preferably set to 10~5000mJ / cm ² or so, and more preferably, 100 to 500 mJ / cm ² or so. The irradiation time is preferably about 1 to 1000 nsec, more preferably about 10 to 100 nsec. When the energy density is low or the irradiation time is short, sufficient ablation or the like does not occur, and when the energy density is high or the irradiation time is long, irradiation light transmitted through the separation layer 120 adversely affects the transfer target layer 140. May cause.

  As a countermeasure against the case where the irradiation light transmitted through the separation layer 120 reaches the transfer-receiving layer 140 and exerts an adverse effect, for example, as shown in FIG. 30, a tantalum (Ta) layer is formed on the separation layer (laser absorption layer) 120. ), And the like. As a result, the laser light transmitted through the separation layer 120 is completely reflected at the interface of the metal film 124, and does not adversely affect the thin film device above it.

  Next, as shown in FIG. 5, a force is applied to the substrate 100 to separate the substrate 100 from the separation layer 120. Although not shown in FIG. 5, a separation layer may adhere to the substrate 100 after the separation.

  Next, as shown in FIG. 6, the remaining separation layer 120 is removed by, for example, a method such as cleaning, etching, ashing, polishing, or a combination thereof. As a result, the transfer target layer (thin film device layer) 140 is transferred to the transfer body 180.

  Note that if a part of the separation layer is also attached to the separated substrate 100, the separation layer is similarly removed. When the substrate 100 is made of an expensive or rare material such as quartz glass, the substrate 100 is preferably provided for reuse. That is, the present invention can be applied to the substrate 100 to be reused, and is highly useful.

Through the above steps, the transfer of the transfer target layer (thin film device layer) 140 to the transfer body 180 is completed. Thereafter, removal of the SiO ₂ film adjacent to the transferred layer (thin film device layer) 140, formation of a conductive layer such as wiring on the transferred layer 140, or formation of a desired protective film can also be performed.

  In this manner, the transferred layer (thin film device layer) 140 itself, which is the object to be peeled, is not directly peeled but is peeled at the separation layer bonded to the transferred layer (thin film device layer) 140. Irrespective of the characteristics, conditions, etc. of the object (transferred layer 140), it can be easily and reliably peeled off (transferred) uniformly, and damage to the object (transferred layer 140) due to the peeling operation is also reduced. Therefore, high reliability of the transferred layer 140 can be maintained.

  Next, an example of a specific manufacturing process in the case of forming a TFT having a CMOS structure, for example, as the thin film device layer 140 on the substrate 100 and the separation layer 120 and transferring this to a transfer body will be described with reference to FIGS. Will be explained. It should be noted that a description will also be given of a separation-promoting ion implantation step performed during this process.

(Step 1)
As shown in FIG. 8, on a light-transmitting substrate (for example, a quartz substrate) 100, an isolation layer (for example, an amorphous silicon layer formed by an LPCVD method) 120, an intermediate layer (for example, a SiO ₂ film) 142, An amorphous silicon layer 143 (formed by, for example, an LPCVD method) is sequentially laminated and formed, and then the entire surface of the amorphous silicon layer 143 is irradiated with laser light from above to perform annealing. Thereby, the amorphous silicon layer 143 is recrystallized to become a polysilicon layer. When the laser annealing is performed by beam scanning in this case, unlike the above-described beam scanning on the separation layer 120, the beam centers of the respective beams overlap each other (except for the Gaussian beam). It is preferable that the same location is irradiated with light twice or more. In this case, there is no adverse effect such as light leakage and the amorphous silicon layer 143 can be sufficiently recrystallized by multiple irradiation.

  The timing of performing the step of implanting the ions for promoting separation is after the formation of the separation layer 120 and before the laser annealing step for crystallization, since ion implantation can be performed without a mask. preferable.

Therefore, the implementation timing
(A) After the formation of the separation layer 120 in FIG. 8 and before the formation of the intermediate layer 142 (B) After the formation of the intermediate layer 142 and before the formation of the amorphous silicon layer 143 (C) After the formation of the amorphous silicon layer 143 Thus, this is either before the laser annealing step for the crystallization. Of these (A) to (C), the timing of performing (C) is most preferable. The reason for this is that the process temperature for forming the amorphous silicon layer 143, that is, the process for forming the channel layer, currently has a process temperature of about 425 ° C. At this time, for example, if hydrogen ions have already been implanted into the separation layer 120 as separation-promoting ions, hydrogen may escape from the separation layer 120 at a temperature of 350 ° C. or higher. Therefore, it is preferable that the step of implanting the ions for promoting separation be performed at the implementation time (C) after the formation of the channel layer. However, since there is no such limitation depending on the type of the ion for accelerating the peeling, it can be performed even at the implementation timings (A) and (B). In addition, it is preferable in terms of transistor characteristics that the layer after the amorphous silicon layer 143 has been laser-annealed and polycrystallized be free of damage due to implantation of separation-promoting ions. In the case of (A) and (B), there is no damage itself, and in the case of (C), even if the amorphous silicon layer 143 itself is damaged, the influence of the damage is caused by the subsequent crystallization step. Reduced.

  Note that this ion implantation step for promoting separation can be performed using a known ion implantation apparatus. That is, when hydrogen ions are implanted, for example, a gas containing hydrogen is turned into plasma, and the hydrogen ions generated thereby are accelerated by an electric field, so that the hydrogen ions can be implanted into the separation layer 120.

The ion implantation step may be performed (D) after laser annealing. In this case, if ion implantation is performed while masking a portion to be a channel region, transistor characteristics do not deteriorate. Note that the mask is removed after the ion implantation step. (Step 2)
Subsequently, as shown in FIG. 9, the polysilicon layer obtained by laser annealing is patterned to form islands 144a and 144b as channel patterns.

  The exfoliation promoting ion implantation step can be performed after the second step (channel pattern formation step) in addition to the above-described (A) to (D) as the execution time (E). In this case, as shown in FIG. 31, a mask pattern 201 is formed on portions of the islands 144a and 144b and facing the channel regions in the islands 144a and 144b. In this state, ions for promoting separation, for example, hydrogen ions are implanted toward the separation layer 120. Thus, hydrogen is not contained in the channel region, and the transistor characteristics do not deteriorate. It should be noted that, after the peeling promotion ion implantation step is completed, the mask pattern 201 is removed.

(Step 3)
As shown in FIG. 10, gate insulating films 148a and 148b covering islands 144a and 144b are formed by, for example, a CVD method.

  The separation promoting ion implantation step can be performed after the third step (gate insulating film) in addition to the above-described (A) to (E) as the execution time (F). In this case, as shown in FIG. 32, it is preferable that a mask pattern 202 is formed on the gate insulating films 148a and 148b in a portion facing the channel region in the islands 144a and 144b.

(Step 4)
As shown in FIG. 11, gate electrodes 150a and 150b made of polysilicon or metal are formed.

(Step 5)
As shown in FIG. 12, a mask layer 170 made of polyimide or the like is formed, and ion implantation of, for example, boron (B) is performed in a self-aligned manner using the gate electrode 150b and the mask layer 170 as a mask. Thus, p ⁺ layers 172a and 172b are formed.

The separation promoting ion implantation step can be performed simultaneously with the boron ion implantation step, in addition to the above-described (A) to (F), as the execution timing (G). In this case, for example, a mixed gas of B ₂ H ₆ (5%) + H ₂ (95%) is turned into plasma, and the boron ions and hydrogen ions generated thereby are accelerated and led to the substrate without passing through a mass analyzer. . Then, even at the same accelerating voltage, heavy boron ions stay in the upper polycrystalline silicon layer, while light hydrogen ions are implanted deeper and reach the separation layer 120.

  At this time, the gate electrode 150b functions in the same manner as the mask pattern 201 in FIG. 31 or the mask pattern 202 in FIG. 32, but a mask layer can be further provided on the gate electrode 150b according to the acceleration voltage.

(Step 6)
As shown in FIG. 13, a mask layer 174 made of polyimide or the like is formed, and ion implantation of, for example, phosphorus (P) is performed in a self-aligned manner using the gate electrode 150a and the mask layer 174 as a mask. As a result, n ⁺ layers 146a and 146b are formed.

The exfoliation promoting ion implantation step can be performed simultaneously with the phosphorus ion implantation step, in addition to the above-described (A) to (G), as the execution time (H). Also in this case, for example, a mixed gas of PH ₃ (5%) + H ₂ (95%) is turned into plasma, and the generated phosphorus ions and hydrogen ions are accelerated and guided to the substrate without passing through a mass analyzer. Then, even at the same accelerating voltage, heavy phosphorus ions remain in the upper polycrystalline silicon layer, while light hydrogen ions are implanted deeper and reach the separation layer 120.

  In this case, the gate electrode 150a functions similarly to the mask pattern 201 in FIG. 31 or the mask pattern 202 in FIG. 32, but a mask layer can be further provided on the gate electrode 150a in accordance with the acceleration voltage.

  Also, the timings (G) and (H) of the above-described separation promoting ion implantation step were the same as the step of implanting the impurity ions into the source and drain regions in the step 5 and the step 6, but separately before and after the step. You can do it.

(Step 7)
As shown in FIG. 14, after forming an interlayer insulating film 154 and selectively forming contact holes, electrodes 152a to 152d are formed.

  The TFT having the CMOS structure formed as described above corresponds to the transfer target layer (thin film device layer) 140 in FIGS. Note that a protective film may be formed over the interlayer insulating film 154.

(Step 8)
As shown in FIG. 15, an epoxy resin layer 160 as an adhesive layer is formed on a CMOS-structured TFT, and then the TFT is transferred to a transfer body (for example, a soda glass substrate) 180 via the epoxy resin layer 160. paste. Subsequently, heat is applied to cure the epoxy resin, and the transfer body 180 and the TFT are bonded (joined).

  Note that the adhesive layer 160 may be a photopolymer resin that is an ultraviolet curable adhesive. In this case, the polymer is cured by irradiating ultraviolet rays instead of heat from the transfer body 180 side.

(Step 9)
As shown in FIG. 16, for example, Xe—Cl excimer laser light is irradiated from the back surface of the translucent substrate 100. As a result, delamination occurs in the separation layer 120 and / or at the interface.

(Step 10)
As shown in FIG. 17, the substrate 100 is peeled off.

(Step 11)
Finally, the separation layer 120 is removed by etching. As a result, as shown in FIG. 18, the TFT having the CMOS structure is transferred to the transfer body 180.

<Second embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the transferred layer 140 composed of a thin film device layer is transferred twice, and in addition to the steps of the first embodiment shown in FIGS. Steps 33 to 35 are added.

  Here, in the second embodiment, the separation layer 120 shown in FIGS. 2 to 5 is referred to as a first separation layer. In the second embodiment, the adhesive layer 160 in FIGS. 3 to 6 is referred to as a second separation layer. Further, in the second embodiment, the transfer member 180 shown in FIGS. 3 to 6 is referred to as a primary transfer member. Therefore, according to the second embodiment, the transferred layer 140 has been transferred to the primary transfer member 180 via the second separation layer 160 at the stage when the process of FIG.

  Here, in the second embodiment, the material of the second separation layer 160 can be the same as that of the first separation layer 120, in addition to the hot-melt adhesive and the water-soluble adhesive. At this time, in order to facilitate separation at the second separation layer 160, the ion implantation described in the first embodiment can be performed.

  Hereinafter, additional steps 1 to 3 of FIGS. 33 to 35 performed after the step of FIG. 6 will be described.

[Additional process 1]
6, the secondary transfer layer 200 is adhered to the lower surface (exposed surface) of the thin film device layer 140 via the adhesive layer 190, as shown in FIG.

  Preferable examples of the adhesive constituting the adhesive layer 190 include various curable adhesives such as a reactive curable adhesive, a thermosetting adhesive, a light curable adhesive such as an ultraviolet curable adhesive, and an anaerobic curable adhesive. An adhesive may be used. The composition of the adhesive may be, for example, any of epoxy, acrylate, and silicone. The formation of such an adhesive layer 190 is performed by, for example, a coating method.

  When the curable adhesive is used, for example, a curable adhesive is applied to the lower surface of the layer to be transferred (thin film device layer) 140, and after the secondary transfer body 200 is joined, the characteristics of the curable adhesive are adjusted. The curable adhesive is cured by a curing method, and the layer to be transferred (thin film device layer) 140 and the secondary transfer body 200 are bonded and fixed.

  When the adhesive is a photo-curing type, light is preferably irradiated from the outside of the light-transmissive secondary transfer body 200. As the adhesive, if a photo-curing adhesive such as an ultraviolet-curing type which hardly affects the thin film device layer is used, the light-transmitting primary transfer member 180 or the light-transmitting primary and secondary transfer members 180 can be used. , 200 from both sides.

  It is to be noted that, unlike the illustration, an adhesive layer 190 may be formed on the secondary transfer body 200 side, and a layer to be transferred (thin film device layer) 140 may be bonded thereon. For example, when the secondary transfer body 200 itself has an adhesive function, the formation of the adhesive layer 190 may be omitted.

  The secondary transfer body 200 is not particularly limited, but includes a substrate (plate material), particularly a transparent substrate. Note that such a substrate may be a flat plate or a curved plate.

  Further, the secondary transfer member 200 may be inferior to the substrate 100 in properties such as heat resistance and corrosion resistance. The reason is that, in the present invention, the transfer target layer (thin film device layer) 140 is formed on the substrate 100 side, and then the transfer target layer (thin film device layer) 140 is transferred to the secondary transfer member 200. This is because the characteristics required for the body 200, particularly the heat resistance, do not depend on the temperature conditions and the like when the transfer layer (thin film device layer) 140 is formed. This is the same for the primary transfer member 180.

  Therefore, assuming that the maximum temperature at the time of forming the transfer layer 140 is Tmax, a material having a glass transition point (Tg) or a softening point of Tmax or less should be used as the constituent material of the primary and secondary transfer members 180 and 200. Can be. For example, the primary and secondary transfer members 180 and 200 can be made of a material having a glass transition point (Tg) or softening point of preferably 800 ° C. or lower, more preferably 500 ° C. or lower, and further preferably 320 ° C. or lower. .

  As the mechanical characteristics of the primary and secondary transfer members 180 and 200, those having a certain degree of rigidity (strength) are preferable, but those having flexibility and elasticity may be used.

  Examples of the constituent material of the primary and secondary transfer members 180 and 200 include various synthetic resins and various glass materials. In particular, various synthetic resins and ordinary (low melting point) inexpensive glass materials are preferable.

  As the synthetic resin, any of a thermoplastic resin and a thermosetting resin may be used. For example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), cyclic polyolefins, modified Polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamide imide, polycarbonate, poly- (4-methylbenten-1), ionomer, acrylic resin, polymethyl methacrylate, acrylic-styrene copolymer (AS Resin, butadiene-styrene copolymer, polio copolymer (EVOH), polyethylene terephthalate (PET), polyester such as polybutylene terephthalate (PBT), precyclohexane terephthalate (PCT), Polyester, polyether ketone (PEK), polyether ether ketone (PEEK), polyetherimide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyfluoroethylene Vinylidene chloride, other fluoroplastics, styrene, polyolefin, polyvinyl chloride, polyurethane, fluororubber, chlorinated polyethylene, etc., various thermoplastic elastomers, ethoxy resin, phenol resin, urea resin, melamine resin, Saturated polyesters, silicone resins, polyurethanes, and the like, or copolymers, blends, polymer alloys, and the like containing these as the main component, and one or more of these (for example, two layers) As a laminate of the upper) it can be used.

  Examples of the glass material include silicate glass (quartz glass), alkali silicate glass, soda lime glass, potassium lime glass, lead (alkali) glass, barium glass, borosilicate glass, and the like. Of these, those other than silicate glass have a lower melting point than silicate glass, are relatively easy to mold and process, and are inexpensive, and are therefore preferable.

  In the case where a material formed of a synthetic resin is used as the secondary transfer member 200, the large-sized secondary transfer member 200 can be integrally formed, and can be formed in a complicated shape such as a member having a curved surface or irregularities. Even if there is, it can be easily manufactured, and various advantages such as low material cost and low manufacturing cost can be enjoyed. Therefore, the use of a synthetic resin is advantageous in manufacturing a large and inexpensive device (for example, a liquid crystal display).

  The secondary transfer body 200 is, for example, a device constituting an independent device such as a liquid crystal cell, or a device such as a color filter, an electrode layer, a dielectric layer, an insulating layer, or a semiconductor element. It may constitute a part.

  Further, the primary and secondary transfer members 180 and 200 may be a material such as metal, ceramics, stone, wood paper, or the like, or on any surface constituting a certain article (on the surface of a clock, on the surface of an air conditioner). , On a printed circuit board, etc.), or on the surface of a structure such as a wall, a pillar, a ceiling, or a window glass.

[Additional process 2]
Next, as shown in FIG. 34, the heat-meltable adhesive layer 160 as the second separation layer is heated and melted. As a result, the adhesive force of the heat-meltable adhesive layer 160 is weakened, so that the primary transfer member 180 can be detached by the thin film device layer 140. By removing the hot-melt adhesive adhered to the primary transfer member 180, the primary transfer member 180 can be reused repeatedly.

  In the case where the above-mentioned water-soluble adhesive is used as the second separation layer 160, at least a region including the second separation layer 160 may be brought into contact with water, preferably, immersed in pure water. When the above-mentioned organic solvent-fusible adhesive is used as the second separation layer 160, at least a region including the second separation layer 160 may be brought into contact with the organic solvent. In the case where the above-described adhesive exhibiting a peeling action by heating or irradiation with ultraviolet light is used as the second separation layer 160, at least a region including the second separation layer 160 may be heated or irradiated with ultraviolet light through another layer. . In the case where an ablation layer is used as the second separation layer as in the case of the first separation layer 120, the light separation causes the second separation layer 160 to peel off. At this time, the separation is promoted by the effect of the implanted ions.

[Additional process 3]
Finally, by removing the second separation layer 160 attached to the surface of the thin film device layer 140, the thin film device layer 140 transferred to the secondary transfer body 200 can be obtained as shown in FIG. Here, the stacking relationship of the thin film device layer 140 with respect to the secondary transfer body 200 is the same as the stacking relationship of the thin film device layer 140 with respect to the substrate 100 as shown in FIG.

Through the above steps, the transfer of the transfer target layer (thin film device layer) 140 to the secondary transfer member 200 is completed. Thereafter, removal of the SiO ₂ film adjacent to the transferred layer (thin film device layer) 140, formation of a conductive layer such as wiring on the transferred layer 140, or formation of a desired protective film can also be performed.

  In the second embodiment, the transferred layer (thin film device layer) 140, which is the object to be peeled, is not directly peeled, but is separated at the first separation layer 120 and the second separation layer 160 to perform the secondary transfer. Since the image is transferred to the body 200, the image can be easily and reliably and uniformly transferred irrespective of the characteristics, conditions, and the like of the object to be separated (the layer to be transferred 140). 140), and high reliability of the transferred layer 140 can be maintained.

<Third embodiment>
By using the techniques described in the first and second embodiments, for example, a microcomputer configured using a thin film device as shown in FIG. 19A can be formed on a desired substrate. become.

  In FIG. 19A, a CPU 300, a RAM 320, and an input / output circuit 360, each of which has a circuit formed by using a thin film device, are mounted on a flexible substrate 182 made of plastic or the like. A solar cell 340 having a silicon PIN junction is mounted.

  Since the microcomputer shown in FIG. 19A is formed on a flexible substrate, it has a feature that it is strong against bending as shown in FIG.

<Fourth embodiment>
In the present embodiment, an example of a manufacturing process in the case where an active matrix type liquid crystal display device using an active matrix substrate as shown in FIGS. Will be described.

(Configuration of liquid crystal display device)
As shown in FIG. 20, the active matrix type liquid crystal display device includes an illumination light source 400 such as a backlight, a polarizing plate 420, an active matrix substrate 440, a liquid crystal 460, a counter substrate 480, and a polarizing plate 500.

  Note that when a flexible substrate such as a plastic film is used for the active matrix substrate 440 and the counter substrate 480 of the present invention, a flexible liquid crystal panel using a reflector instead of the illumination light source 400 can provide flexibility. Thus, an active matrix type liquid crystal panel which is strong against impact and lightweight can be realized. Note that when the pixel electrode is formed of metal, the reflection plate and the polarizing plate 420 become unnecessary.

  The active matrix substrate 440 used in this embodiment is a driver-incorporated active matrix substrate in which a TFT is provided in the pixel portion 442 and a driver circuit (scanning line driver and data line driver) 444 is mounted.

  FIG. 21 is a sectional view of a main part of the active matrix type liquid crystal display device, and FIG. 22 is a circuit configuration of a main part of the liquid crystal display device.

  As shown in FIG. 22, the pixel portion 442 includes a TFT (M1) having a gate connected to a gate line G1, one of a source and a drain connected to a data line D1, and the other of a source and a drain connected to a liquid crystal 460. ) And a liquid crystal 460.

  The driver unit 444 includes a TFT (M2) formed by the same process as the TFT (M1) of the pixel unit.

  As shown on the left side of FIG. 21, the TFT (M1) in the pixel portion 442 includes source / drain layers 1100a and 1100b, a channel 1100e, a gate insulating film 1200a, a gate electrode 1300a, an insulating film 1500, and a source. -It is configured to include the drain electrodes 1400a and 1400b.

  Reference numeral 1700 denotes a pixel electrode, and reference numeral 1702 denotes a region where the pixel electrode 1700 applies a voltage to the liquid crystal 460 (a region where a voltage is applied to the liquid crystal). In the figure, the alignment film is omitted. The pixel electrode 1700 is made of ITO (in the case of a light transmission type liquid crystal panel) or metal such as aluminum (in the case of a reflection type liquid crystal panel). In FIG. 21, the base insulating film (intermediate layer) 1000 under the pixel electrode 1700 is completely removed in the voltage application region 1702 to the liquid crystal, but the present invention is not limited to this. If the film (intermediate layer) 1000 is thin and does not hinder the voltage application to the liquid crystal, it may be left.

  As shown on the right side of FIG. 21, the TFT (M2) forming the driver unit 444 includes source and drain layers 1100c and 1100d, a channel 1100f, a gate insulating film 1200b, a gate electrode 1300b, and an insulating film. 1500 and source / drain electrodes 1400c and 1400d.

In FIG. 21, reference numeral 480 is, for example, a counter substrate (for example, a soda glass substrate), and reference numeral 482 is a common electrode. Reference numeral 1000 denotes an SiO ₂ film, reference numeral 1600 denotes an interlayer insulating film (for example, an SiO ₂ film), and reference numeral 1800 denotes an adhesive layer. Reference numeral 1900 denotes a substrate (transfer body) made of, for example, a soda glass substrate.

(Manufacturing process of liquid crystal display device)
Hereinafter, a manufacturing process of the liquid crystal display device of FIG. 21 will be described with reference to FIGS.

  First, the TFTs (M1, M2) as shown in FIG. 23 are formed on a substrate 3000 (for example, a quartz substrate) that has high reliability and transmits laser light through the same manufacturing process as in FIGS. And a protective film 1600. In FIG. 23, reference numeral 3100 denotes a separation layer (laser absorption layer) into which separation-promoting ions have been implanted. In FIG. 23, the TFTs (M1, M2) are both n-type MOSFETs. However, the present invention is not limited to this, and may be a p-type MOSFET or a CMOS structure.

  Next, as shown in FIG. 24, the protective film 1600 and the base insulating film 1000 are selectively etched to form openings 4000 and 4200 selectively. These two openings are formed simultaneously using a common etching process. Although the base insulating film (intermediate layer) 1000 is completely removed from the opening 4200 in FIG. 24, the present invention is not limited to this. If it does not hinder the application of voltage to, it may be left.

  Next, as shown in FIG. 25, a pixel electrode 1700 made of an ITO film or a metal such as aluminum is formed. When an ITO film is used, a transmissive liquid crystal panel is used. When a metal such as aluminum is used, a reflective liquid crystal panel is used. Next, as shown in FIG. 26, the substrate 1900 is joined (adhered) via the adhesive layer 1800.

  Next, as shown in FIG. 26, an excimer laser beam is irradiated from the back surface of the substrate 3000 to cause a separation phenomenon in the separation layer 120 by utilizing the action of the separation promoting ions. Thereafter, the substrate 3000 is peeled off. At this time, since no great force is required for peeling, no mechanical damage occurs to the TFT or the like.

Next, the separation layer (laser absorption layer) 3100 is removed. Thus, an active matrix substrate 440 as shown in FIG. 27 is completed. The bottom surface (region 1702) of the pixel electrode 1700 is exposed, and can be electrically connected to the liquid crystal. Thereafter, an alignment film is formed on the surface of the insulating film (intermediate layer such as SiO ₂ ) 1000 of the active matrix substrate 440 and the surface of the pixel electrode 1702, and the alignment processing is performed. In FIG. 27, the alignment film is omitted.

  Then, a common electrode facing the pixel electrode 1709 is further formed on the surface thereof, and the opposing substrate 480 whose surface is oriented and the active matrix substrate 440 of FIG. 21 are sealed with a sealing material (sealant). Liquid crystal is sealed between the two substrates to complete a liquid crystal display device as shown in FIG.

<Fifth embodiment>
FIG. 28 shows a fifth embodiment of the present invention.

  In this embodiment, the above-described thin film device transfer method is executed a plurality of times, and a plurality of patterns including the thin film device are transferred onto a substrate (transfer body) larger than the transfer source substrate. Forming an active matrix substrate.

  That is, the transfer is performed a plurality of times on the large substrate 7000 to form the pixel portions 7100a to 7100P. As shown by the dashed line on the upper side of FIG. 28, a TFT and a wiring are formed in the pixel portion. In FIG. 28, reference numeral 7210 is a scanning line, reference numeral 7200 is a signal line, reference numeral 7220 is a gate electrode, and reference numeral 7230 is a pixel electrode.

  Create a large-scale active matrix substrate with a reliable thin-film device by using a reliable substrate repeatedly or by transferring a thin-film pattern multiple times using multiple first substrates it can.

<Sixth Embodiment>
FIG. 29 shows a sixth embodiment of the present invention.

  The feature of the present embodiment is that the above-described thin-film device transfer method is executed a plurality of times, and thin-film devices having different design rules (that is, design rules for pattern design) are formed on a substrate larger than the transfer source substrate. To transfer a plurality of patterns including devices (that is, thin film devices having different minimum line widths).

  In FIG. 29, a driver circuit (8000 to 8032) formed by a finer manufacturing process than a pixel portion (7100a to 7100p) is transferred around the substrate 6000 by a plurality of transfers on an active matrix substrate with a driver. Has been created.

  The shift register that constitutes the driver circuit operates at a logic level under a low voltage, so that the withstand voltage may be lower than that of the pixel TFT. Therefore, it is possible to achieve higher integration by making the TFT smaller than the pixel TFT. it can.

  According to the present embodiment, a plurality of circuits having different design rule levels (that is, different manufacturing processes) can be realized on one substrate. Note that the sampling means (the thin film transistor M2 in FIG. 22) for sampling the data signal under the control of the shift register needs to have a high breakdown voltage like the pixel TFT.

〔Example〕
Next, specific examples of the present invention will be described.

(Example 1)
A quartz substrate (softening point: 1630 ° C., strain point: 1070 ° C., transmittance of excimer laser: almost 100%) having a length of 50 mm × width 50 mm × thickness 1.1 mm was prepared, and a separation layer was formed on one side of the quartz substrate. An amorphous silicon (a-Si) film was formed as a (laser light absorbing layer) by a low pressure CVD method (Si ₂ H ₆ gas, 425 ° C.). The thickness of the separation layer was 100 nm.

Next, an SiO ₂ film was formed as an intermediate layer on the separation layer by an ECR-CVD method (SiH ₄ + O ₂ gas, 100 ° C.). The thickness of the intermediate layer was 200 nm.

Next, an amorphous silicon film having a thickness of 50 nm is formed on the intermediate layer by a low-pressure CVD method (Si ₂ H ₆ gas, 425 ° C.) as a layer to be transferred. (308 nm) for crystallization to form a polysilicon film. Thereafter, the polysilicon film was subjected to predetermined patterning to form a region serving as a source, a drain, and a channel of the thin film transistor. After that, a 1200 nm gate insulating film SiO ₂ is formed by a TEOS-CVD method (SiH ₄ + O ₂ gas), and then a gate electrode (a high melting point metal such as Mo is laminated on polysilicon is formed on the gate insulating film). ) And ion implantation using the gate electrode as a mask to form self-aligned (self-aligned) source / drain regions to form thin film transistors. At this time, hydrogen ions were simultaneously injected into the separation layer. Thereafter, if necessary, electrodes and wirings connected to the source / drain regions and wirings connected to the gate electrodes are formed. Although Al is used for these electrodes and wirings, the present invention is not limited to this. Further, when there is a concern about melting of Al due to laser irradiation in a later step, a metal having a higher melting point than Al (a metal not melted by laser irradiation in a later step) may be used.

  Next, an ultraviolet curable adhesive is applied on the thin film transistor (film thickness: 100 μm), and a large transparent glass of 200 mm length × 300 mm width × 1.1 mm thickness is applied to the coating film as a transfer body. After bonding the substrates (soda glass, softening point: 740 ° C., strain point: 511 ° C.), the adhesive was cured by irradiating ultraviolet rays from the glass substrate side, and these were bonded and fixed.

Next, Xe-Cl excimer laser (wavelength: 308 nm) was irradiated from the quartz substrate side, and a beam scan shown in FIG. 31 and subsequent drawings was performed to cause separation (intralayer separation and interface separation) in the separation layer. . The energy density of the irradiated Xe-Cl excimer laser was 250 mJ / cm ² , and the irradiation time was 20 nsec. Excimer laser irradiation includes spot beam irradiation and line beam irradiation. In the case of spot beam irradiation, a predetermined unit area (for example, 8 mm × 8 mm) is irradiated with a spot, and this spot irradiation is performed in each irradiation area. Irradiation was performed while scanning the beam so that they did not overlap (so that they did not overlap at the front, back, left and right). Further, in the case of line beam irradiation, the irradiation regions of the respective times do not overlap each other in a predetermined unit region (for example, 378 mm × 0.1 mm or 378 mm × 0.3 mm (these regions are regions where 90% or more of energy is obtained)). The beam was irradiated while scanning as described above.

  Thereafter, the quartz substrate and the glass substrate (transfer body) were peeled off at the separation layer, and the thin film transistor and the intermediate layer formed on the quartz substrate were transferred to the glass substrate.

  After that, the separation layer attached to the surface of the intermediate layer on the glass substrate side was removed by etching, washing, or a combination thereof. The same processing was performed on the quartz substrate, and the quartz substrate was reused.

  If the glass substrate serving as the transfer body is a substrate larger than the quartz substrate, the transfer from the quartz substrate to the glass substrate as in the present embodiment is repeatedly performed on different areas in a plane, and on the glass substrate, More thin film transistors than the number of thin film transistors that can be formed over the quartz substrate can be formed. Further, the thin film transistor can be repeatedly stacked over a glass substrate to form more thin film transistors.

(Example 2)
The transfer of the thin film transistor was performed in the same manner as in Example 1 except that the separation layer was an amorphous silicon film containing 20 at% of H (hydrogen) in the separation layer formation process.

  The adjustment of the amount of H in the amorphous silicon film was performed by appropriately setting conditions at the time of film formation by the low-pressure CVD method.

(Example 3)
The transfer of the thin film transistor was performed in the same manner as in Example 1 except that the separation layer was a ceramic thin film (composition: PbTiO ₃ , thickness: 200 nm) formed by a sol-gel method by spin coating.

(Example 4)
The transfer of the thin film transistor was performed in the same manner as in Example 1 except that the separation layer was a ceramic thin film (composition: BaTiO ₃ , thickness: 400 nm) formed by sputtering.

(Example 5)
The thin film transistor was transferred in the same manner as in Example 1 except that the separation layer was a ceramic thin film (composition: Pb (Zr, Ti) O ₃ (PZT), film thickness: 50 nm) formed by a laser-ablation method. Was.

(Example 6)
A thin film transistor was transferred in the same manner as in Example 1 except that the separation layer was a polyimide film (thickness: 200 nm) formed by spin coating.

(Example 7)
A thin film transistor was transferred in the same manner as in Example 1, except that the separation layer was a polyphenylene sulfide film (thickness: 200 nm) formed by spin coating.

(Example 8)
A thin film transistor was transferred in the same manner as in Example 1 except that the separation layer was an Al layer (thickness: 300 nm) formed by sputtering.

(Example 9)
A thin film transistor was transferred in the same manner as in Example 2 except that Kr-F excimer laser (wavelength: 248 nm) was used as irradiation light. The energy density of the irradiated laser was 250 mJ / cm ² , and the irradiation time was 20 nsec.

(Example 10)
The transfer of the thin film transistor was performed in the same manner as in Example 2 except that an Nd-YAIG laser (wavelength: 1068 nm) was used as the irradiation light. The energy density of the irradiated laser was 400 mJ / cm ² , and the irradiation time was 20 nsec.

(Example 11)
A thin film transistor was transferred in the same manner as in Example 1 except that a thin film transistor having a polysilicon film (thickness: 80 nm) was formed by a high-temperature process at 1000 ° C. as a transfer target layer.

(Example 12)
A thin film transistor was transferred in the same manner as in Example 1 except that a transparent substrate made of polycarbonate (glass transition point: 130 ° C.) was used as a transfer body.

(Example 13)
A thin film transistor was transferred in the same manner as in Example 2 except that a transparent substrate made of an AS resin (glass transition point: 70 to 90 ° C.) was used as a transfer body.

(Example 14)
A thin film transistor was transferred in the same manner as in Example 3 except that a transparent substrate made of polymethyl methacrylate (glass transition point: 70 to 90 ° C.) was used as a transfer body.

(Example 15)
A thin film transistor was transferred in the same manner as in Example 5, except that a transparent substrate made of polyethylene terephthalate (glass transition point: 67 ° C.) was used as the transfer body.

(Example 16)
A thin film transistor was transferred in the same manner as in Example 6, except that a transparent substrate made of high-density polyethylene (glass transition point: 77 to 90 ° C.) was used as the transfer body.

(Example 17)
A thin film transistor was transferred in the same manner as in Example 9, except that a transparent substrate made of polyamide (glass transition point: 145 ° C.) was used as the transfer body.

(Example 18)
A thin film transistor was transferred in the same manner as in Example 10 except that a transparent substrate made of an epoxy resin (glass transition point: 120 ° C.) was used as a transfer body.

(Example 19)
A thin film transistor was transferred in the same manner as in Example 11 except that a transparent substrate made of polymethyl methacrylate (glass transition point: 70 to 90 ° C.) was used as a transfer body.

  In each of Examples 1 to 19, the state of the transferred thin film transistor was visually observed with a naked eye and a microscope. As a result, the transfer was uniformly performed without any defect or unevenness.

  As described above, the use of the transfer technique of the present invention makes it possible to transfer a thin-film device (transferred layer) to various types of transfer media. Could be done without difficulty. Thus, for example, a material that cannot be directly formed or is not suitable for forming a thin film, a material that is easily formed, a material that is formed of an inexpensive material, or a large object that is difficult to move. It can be formed by transfer.

  In particular, as the transfer body, materials having inferior properties such as heat resistance and corrosion resistance as compared with the substrate material, such as various synthetic resins and glass materials having a low melting point, can be used. Therefore, for example, when manufacturing a liquid crystal display in which a thin film transistor (especially a polysilicon TFT) is formed on a transparent substrate, a quartz glass substrate having excellent heat resistance is used as a substrate, and various synthetic resins and low melting points are used as a transfer body. By using a transparent substrate made of an inexpensive and easy-to-process material such as a glass material, a large and inexpensive liquid crystal display can be easily manufactured. Such advantages are not limited to the liquid crystal display, and are the same in the manufacture of other devices.

  Further, while receiving the above advantages, a transferred layer such as a functional thin film is formed on a highly reliable substrate, particularly a substrate having high heat resistance such as a quartz glass substrate, and further patterned. Therefore, a highly reliable functional thin film can be formed on the transfer body regardless of the material properties of the transfer body.

  Although such a highly reliable substrate is expensive, it can be reused, thus reducing the manufacturing cost.

FIG. 4 is a cross-sectional view showing a first step in the first embodiment of the method for transferring a thin film device of the present invention. FIG. 5 is a cross-sectional view showing a second step in the first embodiment of the method for transferring a thin film device of the present invention. FIG. 6 is a cross-sectional view showing a third step in the first embodiment of the method for transferring a thin film device of the present invention. FIG. 9 is a sectional view showing a fourth step in the first embodiment of the method for transferring a thin film device of the present invention. It is sectional drawing which shows the 5th process in 1st Embodiment of the transfer method of the thin film device of this invention. It is sectional drawing which shows the 6th process in 1st Embodiment of the transfer method of the thin film device of this invention. FIG. 3 is a diagram showing a change in transmittance of a first substrate (the substrate 100 in FIG. 1) with respect to the wavelength of laser light. FIG. 3 is a cross-sectional view showing a first step for forming the thin film device of FIG. FIG. 4 is a cross-sectional view illustrating a second step for forming the thin-film device of FIG. 2. FIG. 5 is a cross-sectional view showing a third step for forming the thin film device of FIG. FIG. 13 is a cross-sectional view showing a fourth step for forming the thin-film device of FIG. 2. FIG. 13 is a cross-sectional view showing a fifth step for forming the thin film device of FIG. FIG. 13 is a sectional view illustrating a sixth step for forming the thin-film device of FIG. 2. FIG. 13 is a cross-sectional view showing a seventh step for forming the thin-film device of FIG. 2. FIG. 4 is a cross-sectional view for showing in detail a step shown in FIG. 3. FIG. 5 is a cross-sectional view for showing details of a step shown in FIG. 4. FIG. 6 is a cross-sectional view for showing details of a step shown in FIG. 5. FIG. 7 is a cross-sectional view for showing details of a step shown in FIG. 6. 1A and 1B are perspective views of a microcomputer manufactured by using the present invention. FIG. 3 is a diagram illustrating a configuration of a liquid crystal display device. FIG. 3 is a diagram illustrating a cross-sectional structure of a main part of the liquid crystal display device. FIG. 3 is a diagram for explaining a configuration of a main part of the liquid crystal display device. FIG. 3 is a cross-sectional view of a device showing a first step in a method for manufacturing an active matrix substrate using the present invention. FIG. 9 is a cross-sectional view of a device showing a second step in the method for manufacturing an active matrix substrate using the present invention. It is sectional drawing of the device which shows the 3rd process of the manufacturing method of the active matrix substrate using this invention. FIG. 14 is a cross-sectional view of a device showing a fourth step in the method for manufacturing an active matrix substrate using the present invention. FIG. 13 is a cross-sectional view of a device showing a fifth step in the method for manufacturing an active matrix substrate using the present invention. FIG. 4 is a view for explaining another example of the method for transferring a thin film device of the present invention. It is a figure for explaining other examples of the transfer method of the thin film device of the present invention. FIG. 9 is a view for explaining a modification of the method for transferring a thin film device of the present invention. FIG. 10 is a cross-sectional view illustrating a step of implanting separation-promoting ions performed after the step of FIG. 9. FIG. 11 is a cross-sectional view illustrating a step of implanting separation promoting ions performed after the step of FIG. 10. FIG. 7 is a schematic cross-sectional view showing an additional step 1 at the time of double transfer performed subsequent to the step of FIG. 6. FIG. 34 is a schematic cross-sectional view showing an additional step 2 at the time of double transfer performed after the step of FIG. 33. FIG. 35 is a schematic cross-sectional view showing an additional step 3 at the time of double transfer performed after the step of FIG. 34.

Explanation of reference numerals

100 substrate, 120 first separation layer, 140 thin film device layer,
160 second separation layer, 180 primary transfer member, 190 adhesive layer, 200 secondary transfer member

Claims (7)

A first step of forming a first separation layer on a substrate;
A second step of forming a transferred layer including a thin film device on the first separation layer;
A third step of forming a second separation layer made of a water-soluble or organic solvent-soluble adhesive on the transferred layer,
A fourth step of bonding a primary transfer member on the second separation layer;
A fifth step of removing the substrate from the transferred layer, bordering on the first separation layer;
A sixth step of bonding a secondary transfer body to the lower surface of the transfer-receiving layer;
A seventh step of contacting the second separation layer with water or an organic solvent, and removing the primary transfer body from the transfer-receiving layer, bordering on the second separation layer;
And transferring the layer to be transferred including the thin film device to a secondary transfer body. A first step of forming a first separation layer on a substrate;
A second step of forming a transferred layer including a thin film device on the first separation layer;
A third step of forming a second separation layer made of an adhesive having a peeling action by heating or ultraviolet irradiation on the transferred layer;
A fourth step of bonding a primary transfer member on the second separation layer;
A fifth step of removing the substrate from the transferred layer, bordering on the first separation layer;
A sixth step of bonding a secondary transfer body to the lower surface of the transfer-receiving layer;
A seventh step of heating or irradiating the second separation layer with ultraviolet rays to remove the primary transfer body from the transfer-receiving layer with the second separation layer as a boundary;
And transferring the layer to be transferred including the thin film device to a secondary transfer body. In claim 1 or 2,
The sixth step is a method for transferring a thin-film device, wherein a reaction-curable, thermosetting, light-curing, or anaerobic-curing adhesive is used. In any one of claims 1 to 3,
Assuming that the maximum temperature at the time of forming the transfer-receiving layer in the second step is Tmax, a material having a glass transition point (Tg) or a softening point of Tmax or less is used as a material of the primary and secondary transfer bodies. A method for transferring a thin film device, wherein the method is used. In any one of claims 1 to 4,
The method of transferring a thin film device according to claim 5, wherein the fifth step includes a step of causing a peeling phenomenon in a layer and / or an interface of the separation layer. In claim 5,
Before the fifth step, an ion implantation step of implanting ions into the separation layer is provided,
The method according to claim 5, wherein the fifth step includes a step of gasifying the ions implanted into the separation layer.   7. A transfer method for a thin film device, wherein the transfer method according to claim 1 is performed a plurality of times on the secondary transfer body larger than the substrate.

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