JP2000133809A - Peeling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which can easily and surely peel a layer to be transferred which has a large area, irrespective of its characteristics, conditions, etc. SOLUTION: On a substrate 10, an isolation layer 20 made of, e.g. amorphous silicon is formed, and a layer 40 to be transferred is formed directly or via an intermediate layer 30 thereon. A transfer body 60 is bonded on the layer 40 to be transferred via an adhesive layer 50. The substrate 10 is repeatedly irradiated with an irradiating light having high energy, from the rear side of the substrate 10. Interface roughness is generated in isolation layer interfaces 21 and/or 22, and contact area of the interface is reduced, so that the adhesion of the isolation layer interfaces 21 and/or 22 is reduced and exfoliation is generated in the interfaces. Interface roughness of the isolation layer interfaces 21 and/or 22, i.e., the force necessary for exfoliation can be controlled through the irradiation frequency of the irradiation light 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for peeling a layer to be transferred, and more particularly to a method for peeling a layer to be transferred made of a thin film such as a functional thin film and transferring it to various transfer members.

[0002]

2. Description of the Related Art For example, when manufacturing a liquid crystal display (LCD) using a thin film transistor (TFT), a process of forming the thin film transistor on a transparent substrate by a chemical vapor deposition (CVD) method or the like is performed.

There are two types of thin film transistors, one using amorphous silicon and the other using polysilicon.
Further, those using polysilicon are classified into those formed through a high-temperature process and those formed through a low-temperature process. Such a thin film transistor is formed on a fragile, easily broken, and heavy substrate such as flat heat-resistant glass or quartz glass. In addition, heat-resistant glass, quartz glass, and the like are difficult to increase in size and are very expensive as compared with ordinary glass. These drawbacks are an obstacle to producing large and inexpensive liquid crystal displays.

[0004] In order to cope with such a problem, a peeling method for peeling a transferred layer existing on a substrate via a separation layer from the substrate has already been proposed. The peeling of the transferred layer
For example, it can be carried out according to the methods described in JP-A-10-125929, JP-A-10-125930, and JP-A-10-125931.

However, in the above method, a large force is required for peeling the transferred layer. Therefore, although the method is suitable for peeling the transferred layer having a small area, the transferred layer having a large area is coated on the entire surface. It is difficult to peel off without failure.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to remove a transferred layer formed on a large-area substrate without damaging the transferred layer and with a smaller force. It is to provide a method for realizing it.

[0007]

According to the present invention, a separation layer made of amorphous silicon or the like is formed on a substrate, and a thin film device or the like, which is a layer to be transferred, is formed thereon. For example, when a thin film device such as a TFT is formed on a quartz substrate or the like, the interface between the separation layer and the transferred layer or between the separation layer and the substrate is very uniform and clean, and the layers sandwich each other. Strongly adhered. This adhesive force is indispensable for stably forming a thin film device on a substrate.

On the other hand, peeling of the formed transferred layer is made possible by selectively reducing the adhesion at the interface of the previously formed separation layer. In the present invention, the irradiation light of high energy is applied to the interface of the separation layer.
There is provided a method for realizing peeling of the transferred layer by irradiating the transferred layer two or more times. In particular, by repeatedly irradiating the irradiation light to the separation layer, an interface roughness is intentionally generated at the separation layer interface, and the bonding effective area at the separation layer interface is extremely reduced, thereby causing close contact. It is characterized in that the force is reduced and the transferred layer is peeled off.

The transferred layer exhibits various functions after peeling and after being transferred to a transfer member, so that the transferred layer must not be damaged during peeling. Therefore, it is necessary to appropriately select the composition and thickness of the separation layer, the light source and energy density of the irradiation light, the composition of the protective layer for protecting the transferred layer and / or the substrate, and the like. Furthermore,
By appropriately selecting the energy density of irradiation light and the number of times of irradiation, and controlling the interface roughness of the interface of the separation layer, the adhesion at the interface of the separation layer is greatly reduced.

The specific solution of the present invention is described in the following (1) to (20).

(1) A peeling method for peeling a transferred layer present on a substrate via a separating layer from the substrate, wherein the separating layer is irradiated with irradiation light to remove the peeling at the interface of the separating layer. Causing the transferred layer to separate from the substrate.

(2) The method according to the above (1), wherein the separation layer is separated by irradiating the irradiation light twice or more.

(3) The peeling of the separation layer causes roughness at the interface of the separation layer, and utilizes the decrease in adhesion due to the decrease in the contact area between the transfer-receiving layer and the separation layer. The peeling method according to (1) or (2).

(4) The peeling of the separation layer causes roughness at the interface of the separation layer, and utilizes the decrease in adhesion due to the decrease in the contact area between the substrate and the separation layer. Or the peeling method according to any of (3).

(5) The peeling method according to any one of the above (1) to (4), wherein the substrate has transparency to the irradiation light.

(6) The peeling method according to any one of (1) to (5), wherein the substrate is reused after the peeling is completed.

(7) The peeling method according to any one of (1) to (6), wherein the substrate includes a protective layer on the surface of the substrate.

(8) The peeling method according to the above (1) or (7), wherein the peeling of the separation layer involves destruction of the separation layer.

(9) The peeling method according to any one of the above (1) to (8), wherein the transferred layer is a functional thin film or a thin film device.

(10) The method according to any one of the above (1) to (9), wherein the transferred layer is a thin film transistor.

(11) The stripping method according to any one of the above (1) to (10), wherein the separation layer has a light absorbing layer made of amorphous silicon.

(12) The peeling method according to the above (11), wherein the amorphous silicon undergoes a phase transition to polysilicon by irradiation of the irradiation light.

(13) The amorphous silicon contains 2 at% of hydrogen.
The peeling method according to any one of the above (11) to (12), which contains the above.

(14) The stripping method according to any one of the above (1) to (10), wherein the separation layer has a light absorbing layer made of polysilicon.

(15) The stripping method according to the above (14), wherein the polysilicon contains 2 at% or more of hydrogen.

(16) The separation layer absorbs the irradiation light and causes a change in the separation layer, and also prevents the irradiation light from reaching the transfer-receiving layer and damaging the transfer-receiving layer. The peeling method according to any one of the above (1) to (15), wherein

(17) The method according to any one of (1) to (16), wherein the separation layer includes a light-shielding layer and / or a reflection layer for preventing the irradiation light from reaching the transfer-receiving layer. The stripping method as described.

(18) The peeling method according to any one of (1) to (17), wherein the interface roughness of the separation layer can be controlled by the number of irradiations of the irradiation light. .

(19) The peeling method according to any one of the above (1) to (18), wherein the irradiation light is a laser light.

(20) The stripping method according to any one of (1) to (19), wherein the wavelength of the irradiation light is 100 to 350 nm.

(21) The wavelength of the irradiation light is 350 to 1200 nm
The peeling method according to any one of the above (1) to (20).

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The peeling method of the present invention will be described below in detail based on a preferred embodiment shown in the accompanying drawings.

[Step 1] As shown in FIG. 1, a separation layer 20 is formed on one surface of the substrate 10.

When the substrate 10 is irradiated with irradiation light 70 described later, for example, from the substrate back surface 11 side, it is desirable that the substrate 10 has a light-transmitting property through which the irradiation light 70 can be transmitted. Further, the substrate 10 has a separation layer
20, when the process temperature for forming the intermediate layer 30 and the transferred layer 40 described later is Tmax, it is preferable that the material be formed of a material having a strain point equal to or higher than Tmax.

It is preferable that the separation layer 20 has such a property that it absorbs irradiation light described later and thereby causes roughness at the separation layer interface 21 described later. Further, it is more preferable that the material has such a property that the roughness of the separation layer interface 21 can be controlled by repeatedly irradiating the irradiation light 70.

Further, the gas contained in the separation layer 20 may be released by the irradiation of the irradiation light 70, and the released gas may cause a gap at the interface, thereby causing a change in the shape of the interface 21 of the separation layer. In this case, the roughness of the separation layer interface 21 after irradiation with the irradiation light 70 can be controlled by the number of irradiations of the irradiation light 70 and / or the content of the gas element.

The composition of the separation layer 20 is, for example, amorphous silicon.

Amorphous silicon is instantaneously melted by irradiation with light having a high energy such as a laser, and changes to polysilicon when solidified again. When the amorphous silicon is crystallized, a crystal grain boundary is formed.
Cause undulations due to crystal grain boundaries. Furthermore, when repeatedly irradiating the irradiation light 70 to the crystallized separation layer 20,
Since the forms of melting and solidification are different between the crystal grain boundaries and the crystal grains, the roughness of the separation layer interface 21 increases.

Further, this amorphous silicon may contain hydrogen. In this case, the hydrogen content is preferably about 2 at% or more, more preferably about 2 to 20%. As described above, when a predetermined amount of hydrogen is contained, hydrogen is released by the irradiation of the irradiation light, and the released hydrogen causes voids at the interface to form undulations at the interface 21 of the separation layer. Further, when the irradiation light is repeatedly irradiated, the contained hydrogen may be gradually released, and the roughness of the interface may increase. In this case, when the hydrogen is completely released by receiving the irradiation according to the hydrogen content, the change does not occur even if the irradiation light is repeatedly irradiated thereafter.

The composition of the separation layer 20 may include, for example, polysilicon.

Polysilicon, like amorphous silicon, is instantaneously melted by irradiation with light having high energy and solidified again. At this time, since the form of melting and solidification is different between the crystal grain boundary and the crystal grain, the roughness of the separation layer interface 21 can be increased by irradiating the irradiation light 70 repeatedly.

The advantage of employing polysilicon as the composition of the separation layer 20 is that, when the boundary temperature at which amorphous silicon undergoes a phase transition to polysilicon is Tth, the Tmax is set to a temperature equal to or higher than Tth. It is possible. In other words,
The range of the process temperature when forming the transfer layer 40 can be widened.

For example, when a thin film transistor is formed as the layer to be transferred 40, not only a low-temperature process but also a high-temperature process can be applied as a forming method.

The thickness of the separation layer 20 varies depending on various conditions such as the composition, layer structure, and formation method of the separation layer 20, but it is desirable that the separation layer 20 has a thickness sufficient to absorb the irradiation light 70. If the thickness of the separation layer 20 is too small, the irradiation light 70 transmitted without being absorbed by the separation layer 20 may reach the transferred layer 40 and damage the transferred layer 40 in some cases. If the thickness of the separation layer 20 is too large, the energy of the irradiation light 70 may not be transmitted to the separation layer interface 21 and irradiation may cause no change in the interface.

For example, when the separation layer 20 is the above-mentioned amorphous silicon and the irradiation light is a XeCl excimer laser (wavelength 308 nm), the thickness of the separation layer 20 is preferably 25 nm or more, and 50 to 200 nm. More preferably, there is.

The separation layer 20 includes a light-shielding layer and / or a reflection layer for the purpose of preventing the irradiation light 70 from passing through the separation layer and reaching the transfer-receiving layer 40 and affecting the transfer-receiving layer. You can go out.

[Step 2] As shown in FIG. 2, a transfer layer 40 is formed on the separation layer 20 via an intermediate layer 30 (underlying layer).

The intermediate layer 30 is formed for various formation purposes. For example, a protective layer, a conductive layer, and an irradiation light 70 for physically or chemically protecting the transferred layer 40 described later during manufacturing or use. The light-shielding layer or the reflective layer, and the one that exerts at least one of the functions as a barrier layer that prevents the transfer of components to or from the transfer layer 40 are exemplified.

The composition of the intermediate layer 30 is appropriately set according to the purpose of its formation. For example, the composition of the intermediate layer 30 formed between amorphous silicon as the separation layer 20 and the thin film transistor as the transfer layer 40 In the case of ( ₁ ), silicon oxide (SiO ₂ ) is used.

The step of forming the intermediate layer 30 may be omitted, and the transfer layer 40 may be formed directly on the separation layer 20.

[Step 3] As shown in FIG. 3, an adhesive layer 50 is formed on the layer to be transferred 40, and a transfer body 60 is adhered via the adhesive layer 50.

Preferred examples of the adhesive constituting the adhesive layer 50 include a light-curable adhesive such as a reaction-curable adhesive, a thermosetting adhesive, and an ultraviolet-curable adhesive, and an anaerobic-curable adhesive. Various curable adhesives can be used. As the composition of the adhesive,
For example, any type such as an epoxy type, an acrylate type, and a silicone type may be used. Such an adhesive layer 50 is formed by, for example, a coating method, a spin coating method, or the like.

When the curable adhesive is used, for example, a curable adhesive is applied to the transfer layer 40, and a transfer member 60 described later is adhered thereon, and then a curing method according to the characteristics of the curable adhesive is used. By curing the curable adhesive by the
And the transfer body 60 are bonded. Note that, unlike the above order, the adhesive layer 50 may be applied on the transfer body 60, and the transfer target layer 40 may be bonded thereon.

The transfer member 60 is not particularly limited, and may have any composition such as metal, ceramics, glass, plastic, and the like. Also, the shape of the transfer body 60 is not particularly limited, and may be any shape such as a flat surface, a curved surface, a bendable film, and a film.

[Step 4] The separation layer 20 is irradiated with irradiation light 70. FIG. 4 shows an example in which the irradiation light 70 is irradiated from the substrate rear surface 11 side of the substrate 10. The irradiation light 70 is transmitted through the substrate 10 and then irradiated on the separation layer 20. When the irradiation light 70 is irradiated on the separation layer 20, the separation layer 20 undergoes changes such as melting, crystallization, recrystallization, outgassing, and separation of contained impurity elements. This causes the interface roughness at the separation layer interface 21 as shown in FIG. Further, by repeatedly irradiating the irradiation light 70, the interface roughness of the separation layer interface 21 can be increased.

The irradiation light 70 may be applied from the transfer layer 40 side in accordance with the composition and characteristics of the transfer layer 40. In this case, it is desirable that the transferred layer 40 does not undergo any change due to the irradiation of the irradiation light 70, or that the properties required for the transferred layer 40 are not lost after peeling or after transfer.

As a light source of the irradiation light 70, laser light is preferably used. Laser light types include solid lasers such as ruby lasers, YAG lasers, and glass lasers, and H lasers.
It may be of any type, such as a gas laser such as an e-Ne laser, a CO ₂ laser, an excimer laser, or a semiconductor laser using ZnS, GaAs, GaP, GaAlAs or the like as a light emitting source. Especially excimer laser, YAG laser, CO ₂
A laser is preferably used because a high output and a uniform energy density distribution are easily obtained.

The form of laser oscillation may be any of continuous oscillation and pulse oscillation, and the beam shape may be any shape such as spot irradiation or line irradiation.

Depending on the composition and properties of the substrate 10, the separation layer 20, and the transfer layer 40, visible light, infrared light, ultraviolet light, microwaves, or the like emitted from a halogen lamp or the like can be used as the light source of the irradiation light 70.

As described above, the separation layer 20 has an appropriate thickness sufficient to absorb all or most of the irradiation light 70, or the light-shielding layer and / or the reflection layer included in the separation layer 20 is When preventing the transmission of 70, roughness occurs in the separation layer interface 21, while no change occurs in the intermediate layer 30 and the transfer receiving layer 40. At this time, as shown in FIG. 5, the contact area of the separation layer interface 21 between the separation layer 20 and the intermediate layer 30 is greatly reduced, and the adhesion at the separation layer interface 21 is greatly reduced. Peeling becomes possible. Further, as the roughness of the separation layer interface 21 is larger, the transfer-receiving layer 40 can be more easily peeled off with a smaller force.

FIG. 5 shows a case where separation occurs at the separation layer interface 21 between the intermediate layer 30 and the separation layer 20.
As shown in FIG. 6, the same shape change may occur at the separation layer interface 22 between the substrate 10 and the separation layer 20 as described above. In this case, a method of removing the separation layer 20 attached to the transfer target layer 40 by etching or the like can be used. By this method, only the transferred layer 40 and the intermediate layer 30 are transferred
Is completed.

When the adhesion between the separation layer interface 21 and the separation layer interface 22 is the same, the interface to be separated is not limited to either the separation layer interface 21 or the separation layer interface 22. In such a case, separation occurs at the interface having a smaller adhesive force between the separation layer interface 21 and the separation layer interface 22. For example, as shown in FIG. 7, delamination of the separation layer causes separation at an arbitrary interface between the separation layer interface 21 and the separation layer interface 22. In this case, the step of transferring only the transferred layer 40 to the transfer member 60 is completed by removing the separation layer attached to the transferred layer 40 by the above-described etching or the like.

It is to be noted that, unlike the order shown in the drawing, after the separation layer 20 is irradiated with irradiation light 70 to reduce the adhesion of the separation layer interface 21 or 22, the transfer body 60 is bonded via the bonding layer 50. Thereafter, the transfer layer 40 may be peeled off.

The substrate 10 after the peeling can be reused after performing an appropriate treatment such as removal of the separation layer 20 remaining on the surface of the substrate 10. At this time, a layer having a composition different from that of the substrate 10 may be formed in advance on the surface of the substrate 10 for the purpose of protecting the surface of the substrate 10 after being used for reuse.

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

Example 1 A quartz substrate having a diameter of 100 mm and a thickness of 1.1 mm (softening point 1630 ° C., strain point 1070 ° C., transmittance of excimer laser almost 100%) was used as a separation layer on one side of the quartz substrate. An amorphous silicon (a-Si) film was formed by a low pressure CVD method (Si ₂ H ₆ gas, substrate temperature: 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.
It was formed by an ECR-CVD method (SiH ₄ + O ₂ gas, substrate temperature 100 ° C.). The thickness of the intermediate layer was 200 nm.

Next, on the intermediate layer, a film having a thickness of 50
nm amorphous silicon film is formed by a low pressure CVD method (Si ₂ H ₆ gas, substrate temperature 425 ° C.). XeCl excimer laser is applied to this amorphous silicon film from the side of the quartz substrate on which the amorphous silicon film is formed. The amorphous silicon film was crystallized by irradiation with light (wavelength: 308 nm) to form a polysilicon film. After that, 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 SiO ₂ gate insulating film having a thickness of 120 nm is formed by ECR-CVD (SiH ₄ + O ₂ gas, substrate temperature 100 ° C.), and a gate electrode (Ta, Ta, (A film thickness of 750 nm). Thereafter, after predetermined patterning was performed on the gate electrode, ion implantation was performed using the gate electrode as a mask, thereby forming source / drain regions in a self-aligned manner (self-alignment) to form a thin film transistor. After this,
If necessary, electrodes and wires connected to the source / drain regions and wires connected to the gate electrodes were formed.
Al was used for these electrodes and wiring members.

Next, an ultraviolet curable resin was applied on the thin film transistor (film thickness: about 100 mm), and the resin was cured by irradiating ultraviolet rays. This treatment was performed for the purpose of preventing the thin film transistor itself from being destroyed by the stress inherent in the thin film transistor when the separation layer was peeled later, but when the adhesion force of the separation layer is appropriately controlled. Is not necessary.

Next, a XeCl excimer laser (wavelength 308 nm)
Was irradiated from the quartz substrate side to cause interface separation in the separation layer. The energy density of the irradiated XeCl excimer laser was 280 mJ · cm ⁻² , and the irradiation time was 20 nsec. The excimer laser irradiation was a 7 mm × 7 mm spot irradiation.

Laser irradiation was performed on the quartz substrate on which the thin film transistor was formed via the separation layer under the laser irradiation conditions. At this time, the number of irradiations was set to 0, 1 and 10 times.

Thereafter, the same type of UV-curable resin was applied on the surface of the quartz substrate on which the UV-curable resin was applied, and the same type of UV-curable resin was applied thereon. . Thereafter, as shown in FIG. 7, the quartz substrate and the glass substrate (transfer member) are peeled off at the interface between the separation layer and the intermediate layer (SiO ₂ ), and the thin film transistor and the intermediate layer formed on the quartz substrate are separated. Transferred to the glass substrate side.

FIGS. 9 to 11 show the results obtained by observing the separation layer interface 21 after peeling off by using an atomic force microscope (AFM).

As shown in FIG. 9, when laser irradiation was not performed, the surface of the separation layer was very gentle, and the average roughness of the interface was as small as about 0.3 nm. This value is equivalent to the average roughness of the surface of the intermediate layer which is the layer to be transferred.

As shown in FIG. 10, when laser irradiation is performed once, irregularities occur on the inner surface of the separation layer, and the average roughness of the interface increases to about 0.7 nm.

As shown in FIG. 11, when laser irradiation is performed 10 times, irregularities having an average roughness of about 0.7 nm occur on the surface of the separation layer, as in the region where laser irradiation is performed once.
In addition, the density of protrusions having a height of about 3 nm or more increases.

On the other hand, FIG. 12 shows the result of observing the intermediate layer interface 31 shown in FIG. 8 by AFM after peeling off the quartz substrate and the glass substrate after performing laser irradiation 10 times.
In the figure, even after repeated laser irradiation, the intermediate layer interface 31 has a flat shape, and even if the laser irradiation is repeatedly performed, no change occurs in the intermediate layer 30 and the transferred layer 40. Is shown.

At the time of the peeling, the force required for the peeling is smallest in a region where laser irradiation is performed 10 times.
A large force was required for peeling in the order of the area where laser irradiation was performed once and the area where laser irradiation was not performed. In other words, the greater the roughness of the release layer interface 21, the greater the release layer interface 21
And the intermediate layer 30 have a reduced adhesive force, and can be easily peeled off.

Example 2 A heat-resistant glass substrate was used as the substrate, and the energy density of the XeCl excimer laser was 1100.
The transfer of the thin film transistor was performed in the same manner as in Example 1 except that mJ · cm ⁻² was used.

Example 3 A thin film transistor was transferred in the same manner as in Example 1 except that a YAG laser was used as the irradiation light 70.

Example 4 A thin film transistor was transferred in the same manner as in Example 1 except that a CO ₂ laser was used as the irradiation light 70.

As described above, by irradiating the irradiation light 70, the interface roughness of the peeling layer interface 21 is generated, and by repeating the irradiation, the peeling layer interface 21 is irradiated.
Can be increased in roughness. Note that when using XeCl excimer laser as the irradiation light 70 and using amorphous silicon as the separation layer 20, even if the number of irradiations is set to 10 or more, the number of irradiations is almost the same as the case of 10 times. Changes appear. In other words, the number of times of irradiation is preferably 5 or more, more preferably 5 to 10 times. In contrast, the middle layer 30
The surface does not change depending on the presence or absence of laser irradiation or the number of times. This is true because the irradiated laser light is completely or almost absorbed by the separation layer. As described above, when the irradiation light 70 is a XeCl excimer laser and the separation layer is amorphous silicon,
In order to completely or almost absorb the irradiation light and not to damage the transferred layer 40, the thickness of the separation layer formed of amorphous silicon is preferably 25 nm or more, and more preferably 50 to 200 nm.

As described above, the separation layer 20 completely absorbs the irradiation light 70 without damaging the transfer receiving layer 40 and intentionally causes undulation at the interface of the separation layer 20, whereby the separation layer By greatly reducing the contact area between the transfer layer and the transferred layer and reducing the adhesion at the interface, the transferred layer can be easily and reliably separated.

[0084]

As described above, according to the stripping method of the present invention, stripping can be easily and reliably performed regardless of the characteristics and conditions of the layer to be transferred.

In particular, by controlling the roughness of the interface of the separation layer, the force required for peeling can be greatly reduced, and application to a transfer layer having a large area becomes easy. In addition, peeling failure can be significantly reduced, and the yield of the transferred layer can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a step of an example of a peeling method of the present invention.

FIG. 2 is a cross-sectional view illustrating a process of an embodiment of the peeling method of the present invention.

FIG. 3 is a cross-sectional view illustrating a process of an example of the peeling method of the present invention.

FIG. 4 is a cross-sectional view showing the steps of an example of the peeling method of the present invention.

FIG. 5 is a cross-sectional view showing a step of an example of the peeling method of the present invention.

FIG. 6 is a cross-sectional view showing a step of an example of the peeling method of the present invention.

FIG. 7 is a cross-sectional view showing a step of an example of the peeling method of the present invention.

FIG. 8 is a cross-sectional view showing a step of an example of the peeling method of the present invention.

FIG. 9 is an atomic force microscope (AFM) image showing an interface after separation by the separation method of the present invention.

FIG. 10 is an atomic force microscope (AFM) image showing an interface after separation by the separation method of the present invention.

FIG. 11 is an atomic force microscope (AFM) image showing an interface after separation by the separation method of the present invention.

FIG. 12 is an atomic force microscope (AFM) image showing an interface after separation by the separation method of the present invention.

[Explanation of symbols]

 10 Substrate 11 Backside of substrate 20 Separation layer 21 Separation layer interface in contact with intermediate layer 22 Separation layer interface in contact with substrate 30 Intermediate layer 31 Interlayer interface 40 Transfer layer 50 Adhesive layer 60 Transfer body 70 Irradiation light

Claims (21)

[Claims] 1. A method for separating a transferred layer existing on a substrate via a separation layer from the substrate, wherein the separation layer is irradiated with irradiation light to cause separation at an interface of the separation layer. A method for separating the transferred layer from the substrate. 2. The method according to claim 1, wherein the separation of the separation layer is performed by irradiating the irradiation light.
The method according to claim 1, wherein the method is performed twice or more. 3. The method according to claim 1, wherein the separation of the separation layer causes roughness at an interface of the separation layer, and utilizes a decrease in adhesion due to a decrease in a contact area between the transfer-receiving layer and the separation layer. Or the peeling method according to 2. 4. The method according to claim 1, wherein the separation of the separation layer causes roughness at an interface of the separation layer, and utilizes a decrease in adhesion due to a decrease in a contact area between the substrate and the separation layer. The stripping method according to any one of the above. 5. The method according to claim 1, wherein the substrate has transparency to the irradiation light. 6. The peeling method according to claim 1, wherein the substrate is reused after the peeling is completed. 7. The peeling method according to claim 1, wherein the substrate includes a protective layer on the surface of the substrate. 8. The method according to claim 1, wherein the separation of the separation layer involves destruction of the separation layer. 9. The peeling method according to claim 1, wherein the transferred layer is a functional thin film or a thin film device. 10. The peeling method according to claim 1, wherein the transfer layer is a thin film transistor. 11. The peeling method according to claim 1, wherein said separation layer has a light absorbing layer made of amorphous silicon. 12. The method according to claim 11, wherein said amorphous silicon undergoes a phase transition to polysilicon by irradiation of said irradiation light. 13. The stripping method according to claim 11, wherein the amorphous silicon contains 2 at% or more of hydrogen. 14. The peeling method according to claim 1, wherein said separation layer has a light absorption layer made of polysilicon. 15. The stripping method according to claim 14, wherein the polysilicon contains hydrogen at 2 at% or more. 16. The separation layer absorbs the irradiation light to cause a change in the separation layer and prevents the irradiation light from reaching the transfer-receiving layer and damaging the transfer-receiving layer. The method according to any one of claims 1 to 15, wherein: 17. The method according to claim 1, wherein the separation layer includes a light-shielding layer and / or a reflection layer for preventing the irradiation light from reaching the transfer-receiving layer. . 18. The method according to claim 1, wherein the interface roughness of the separation layer can be controlled by the number of irradiations of the irradiation light. 19. The peeling method according to claim 1, wherein the irradiation light is a laser light. 20. The stripping method according to claim 1, wherein the wavelength of the irradiation light is 100 to 350 nm. 21. The peeling method according to claim 1, wherein the wavelength of the irradiation light is 350 to 1200 nm.