JP2001230393A - Separating method of compound member, manufacturing method of thin film and separating device of compound member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a quantity of loss in the edge of a thin film by improving the reproducibility of the position where a crack is generated on a compound member such as a bonded substrate or the like. SOLUTION: A compound member which is formed by adhering a second member to a first member comprising an isolation layer 4 and a transfer layer 5 which is arranged on the isolation layer 4 is separated by the different position from the adhering interface of the first and the second members. At first, the unsymmetrical force regarding the adhering interface is applied to the edge of the compound member, thereby forming a crack 7A which runs from a surface of the first member 1 to the isolation layer 4 through the transfer layer 5. Next, the crack is grown along the isolation layer 4 so as to separate the compound member completely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for separating a composite member, a method for producing a thin film, and an apparatus for separating a composite member.

[0002]

2. Description of the Related Art Various manufacturing methods have been proposed for forming thin films such as insulators (dielectrics), conductors, semiconductors, and magnetic materials, among which different materials or structures differ from each other. There is a method of forming a thin film by separating a composite member composed of at least two types of layers.

[0003] In order to make it easier to understand, SOI is used as a thin film.
Take layers and explain.

Japanese Patent Application Laid-Open No. 7-302889 and US Pat. No. 5,856,229 disclose a method in which a porous layer is formed on a single-crystal Si substrate, and a non-porous layer single-crystal layer is formed thereon. The composite member formed by bonding the first member to the second member via the insulating layer is separated into two by a porous layer serving as a separation layer, so that the second member has a non-porous structure. A method for transferring a single crystal layer is described. This technique is excellent in that the thickness of the SOI layer is excellent, that the crystal defect density of the SOI layer can be reduced, the surface flatness of the SOI layer is good, and that the SOI layer has a thickness of several tens nm to 10 μm. It is excellent in that an SOI substrate having a layer can be manufactured.

Further, this method has an excellent advantage that the separated Si substrate can be reused because the single crystal Si substrate is separated from the second member without breaking most of the single crystal Si substrate.

As a method of separating the bonded substrates into two, for example, a method in which a force is applied in a direction perpendicular to the bonding surface and both substrates are pulled in opposite directions, (For example, a method in which both substrates are moved in opposite directions in a plane parallel to the bonding surface, or a method in which both substrates are rotated in opposite directions so that a force is applied in a circumferential direction). Method),
A method in which pressure is applied in a direction perpendicular to the bonding surface, a method in which wave energy such as ultrasonic waves is applied to the separation region, and a separation member ( For example, a method of inserting a sharp blade such as a knife), a method of utilizing the expansion energy of a substance impregnated in a porous layer functioning as a separation region, and a method of bonding a porous layer functioning as a separation region from the side of a substrate. There are a method of separating the porous layer by expanding the volume by thermal oxidation and a method of selectively etching and separating the porous layer functioning as a separation region from the side surface of the bonded substrate.

[0007] Such a method is disclosed in US Pat.
No. 4,123, Japanese Patent Application Laid-Open No. Hei 11-237885, Japanese Patent Application Laid-Open No. 10-233352, European Patent Publication 0
No. 866917.

[0008] The specification of Japanese Patent Application Laid-Open No. 5-211128 and US Patent No. 5,374,564 include single crystal Si.
A substrate formed by injecting ions such as hydrogen into the substrate from its surface side and forming an ion-implanted layer with a locally high concentration of implanted ions acting as a separation layer inside the substrate is bonded to another substrate Then, a method of heating and separating the bonded substrates is described.

[0009]

In the above-mentioned separation method, it is important how to stabilize the position where a crack occurs at the beginning of the separation.

For example, when a crack generated in a portion other than the separation layer at the time of separation of the bonded substrate grows toward the center of the substrate, the thin film which becomes the SOI layer is broken, and the production yield of the SOI substrate is reduced. Lower.

The present invention has been made in view of the above background. For example, it is an object of the present invention to improve the reproducibility of the crack generation position in a composite member such as a bonded substrate and to suppress the amount of a thin film defect at an end. As a first object.

It is a second object of the present invention to appropriately separate the composite member with a separation layer such as a porous layer or an ion-implanted layer.

[0013]

According to a first aspect of the present invention, there is provided a separation method, wherein a first member having a separation layer and a transfer layer on the separation layer is in close contact with the second member. A method for separating a composite member, wherein the composite member is separated at a position different from a contact interface between the first member and the second member, wherein a force asymmetrical to the contact interface is applied to an end of the composite member. Acting on the part, a preliminary separation step including a step of forming a crack from the surface of the first member to the separation layer through the transfer layer in the composite member, and forming the crack along the separation layer. And a main separation step including a growing step.

According to a second aspect of the present invention, there is provided a method of manufacturing a thin film, comprising: a first layer having a separation layer and a transfer layer on the separation layer;
For producing a thin film, comprising the steps of: adhering a second member to a second member to form a composite member; and a separating step of separating the first member and the second member at a position different from the contact interface. In the method, the separating step includes applying an asymmetric force to the end of the composite member to the composite member from the surface of the first member through the transfer layer, by applying an asymmetric force to the end of the composite member. A method for producing a thin film, comprising: a first step of forming a crack leading to a crack; and a step of growing the crack along the separation layer.

According to a third aspect of the present invention, there is provided a separation apparatus comprising: a composite member in which a first member having a separation layer and a transfer layer on the separation layer is closely attached to a second member; An apparatus for separating a composite member that separates at a position different from a contact interface between the first member and the second member, by applying an asymmetric force to an end of the composite member with respect to the contact interface. A preliminary separation mechanism for forming a crack in the composite member from the surface of the first member to the separation layer through the transfer layer, and a main separation mechanism for growing the crack along the separation layer. .

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A to 1C are schematic views for schematically explaining a method of separating a composite member according to a preferred embodiment of the present invention.

The first member 1 has a separation layer 4 formed therein. Reference numeral 5 denotes a surface layer (transfer layer) of the first member, which is on the separation layer 4. This surface layer will be transferred to the second member later. Reference numeral 3 denotes a substrate of the first member, which is below the separation layer 4. A first member 1 having a separation layer 4 therein and a second member 2 are brought into close contact with each other to prepare and prepare a composite member 6. 1A shows a contact interface.

The separation method according to the present embodiment uses the composite member 6.
1B to separate the first member 1 and the second member 2 at a position different from the close contact interface 1A, and a main separation step shown in FIG. 1C.

In the preliminary separation step, as shown in FIG.
By applying an asymmetrical force 8 to the end of the composite member 6 with respect to the adhesive interface 1A, a crack 7A from the surface of the first member 1 across the transfer layer 5 to the separation layer 4 is formed on the composite member 6. Form. An external force 8 asymmetrical to the contact interface causes a crack 7 parallel to the contact interface toward the lateral center of the composite member 6.
A suppresses elongation. FIG. 1B shows an example in which the tip of the crack 7A reaches the upper surface of the substrate 3; however, the tip of the crack 7A only needs to reach the upper surface of the separation layer 4 or the inside of the separation layer 4.

In this separation step, as shown in FIG. 1C, a crack 7B is grown along the separation layer 4 from the separation start portion where the crack 7A is formed. In the preliminary separation step, since the crack 7A has already reached the separation layer 4 inside the first member 6, the crack 7A is thereafter provided by applying a separation force 9 for separating the first and second members. 7B is generated and grows along the separation layer 4 inside the separation layer 4 or at the upper and lower interfaces thereof. FIG. 1C illustrates how the crack 7A grows inside the separation layer 4.

In this manner, the transfer layer 5 is transferred to the second member without breaking most of the transfer layer 5, and only a very small part of the end of the transfer layer 5 is not transferred to the second member. Is simply missing.

The transfer layer 5 used in the present invention means a layer in which a crack is formed in the preliminary separation step and separated in the main separation step and transferred to the first member side. As the layer 5, at least one selected from layers made of a material such as an insulator, a conductor, a semiconductor, and a magnetic material is used. When a semiconductor layer is used, single-crystal Si
Layer, polycrystalline Si layer, amorphous Si layer, Ge layer, SiGe
Layer, SiC layer, C layer, compound semiconductor (for example, GaAs
s, InP, GaN, etc.) layer.
In the case of using an insulator layer, specific examples include silicon oxide, silicon nitride, and silicon nitride oxide. When an ion implantation method described later is used as a method for forming the separation layer, the surface layer of the substrate to be implanted becomes the transfer layer.

The separation layer 4 used in the present invention is a layer that provides an exposed surface after separation by cracking inside or on the upper or lower interface in the present separation step. Among them, a layer region or an interface where the mechanical strength is relatively weak, or a layer region or an interface where stress is relatively concentrated can be used as the separation layer in the present invention. Specific examples include a porous layer formed by anodization or ion implantation of hydrogen, nitrogen, a rare gas, or the like. In the case of ion implantation, defects and stress are generated by the ion implantation. Therefore, even if microbubbles are not formed and the porous body is not formed, the mechanical strength is weak, and thus the layer can be used as a separation layer.

Porous Si was discovered by Uhlir et al. In 1956 in the course of the study of electropolishing of semiconductors (A. Uhli
r, Bell Syst. Tech. J., vol. 35, 333 (1956)). Porous Si
Can be formed by anodizing a Si substrate in an HF solution.

Unagimi et al. Studied the dissolution reaction of Si in anodization and reported that the anodic reaction of Si in HF solution requires holes, and the reaction is as follows ( T. Unakazumi, J. Electrochem. Soc., Vol. 127, 476 (198
0)). Si + 2HF + (2-n) e ⁺ → SiF ₂ + 2H ⁺ + ne ^- SiF ₂ + 2HF → SiF ₄ + H ₂ SiF ₄ + 2HF → H ₂ SiF ₆ or Si + 4HF + (4-λ) e ⁺ → SiF ₄ + 4H ⁺ + λe ^- SiF ₄ + 2HF → H ₂ SiF ₆ Here, e + and e- represent a hole and an electron, respectively. Further, n and λ are the number of holes required for dissolving one atom of Si, respectively, and it is assumed that porous Si is formed when the condition of n> 2 or λ> 4 is satisfied. .

From the above, it can be considered that P-type Si having holes is made porous, while N-type Si is not made porous. The selectivity in this porous formation has been reported by Nagano et al. And Imai (Nagano, Nakajima, Yasuno, Onaka, Kajiwara, IEICE Technical Report, vol.79, SSD79-9
549 (1979)), (K. Imai, Solid-State Electronics, vol.2
4,159 (1981)).

However, there is also a report that a high concentration of N-type Si can be made porous (RP Holmstrom and J. et al.
Y. Chi, Appl. Phys. Lett., Vol. 42, 386 (1983)).
Therefore, it is important to select a substrate that can be made porous regardless of whether it is a P-type or an N-type.

After forming the composite member by bringing the first and second members into close contact with each other, the composite member may be heat-treated in an oxidizing atmosphere to increase the adhesion strength, and an oxide film may be formed on the exposed surface of the composite member. preferable. In this case, since the end of the composite member serving as the separation start portion is also covered with the oxide film, the separation can be performed well by applying the method of the present invention.

The method of applying an asymmetric external force used in the preliminary separation step and the method of applying the external force used in the main separation step will be described later with reference to the drawings.

2A to 2G are schematic views for schematically explaining a method for manufacturing an SOI substrate according to a preferred embodiment of the present invention.

First, in the step shown in FIG.
A substrate 11 is prepared, and a porous Si layer (separation layer) 12 is formed on the surface thereof by anodizing treatment or the like.

Next, in the step shown in FIG.
A non-porous single-crystal Si layer 13 is formed on the i-layer 12 by an epitaxial growth method. After that, the surface is oxidized to form an insulating layer (SiO ₂ layer) 14.
As a result, a first substrate (first member) 10 is formed. The single-crystal Si layer 13 and the insulating layer 14 become transfer layers.

Here, the porous Si layer 12 may be formed by, for example, a method of implanting an inert gas ion such as hydrogen ion or helium into the single crystal Si substrate 11 (ion implantation method). The porous Si layer formed by this method has a large number of microcavities, and the microcavities
Also called a layer.

Next, in the step shown in FIG.
Is prepared, and the first substrate 10 and the second substrate 20 are brought into close contact with each other at room temperature such that the second substrate 20 and the insulating layer 14 face each other. To create a bonded substrate (composite member).

The insulating layer 14 may be formed on the single-crystal Si layer 13 side of the first substrate as described above, may be formed on the second substrate 20, or may be formed on both. May be
As a result, when the first substrate and the second substrate are brought into close contact,
The state shown in FIG. 2C may be obtained. However, as described above, by forming the insulating layer 14 on the side of the single-crystal Si layer 13 serving as an active layer, the first substrate 10 and the second substrate 20 are formed.
Since the bonding interface (adhesion interface) with the active layer can be kept away from the active layer, a higher-quality SOI substrate can be obtained.

Next, in a step (preliminary separation step) shown in FIG. 2D, a separation start unit 6 which is a part where separation processing is started.
0 is formed. The separation start part 60 is a part that starts separation of the bonded substrate 30 in the next separation step (FIG. 1E).

In a preferred embodiment of the present invention, an asymmetrical force is applied to the end of the bonded substrate 30 with respect to the close interface between the first substrate 10 and the second substrate 20. In particular, a separation member having an asymmetric structure (for example, a solid wedge) or a substrate holding mechanism having an asymmetric structure may be used.

As a method of applying an "asymmetrical force" to the first substrate 10 and the second substrate 20, for example, the following method is suitable.

A method of inserting a solid wedge having a structure and / or function to apply an asymmetric force to the close contact interface between the first substrate 10 and the second substrate 20 is inserted into the end of the bonded substrate 30. It is suitable.

More specifically, for example, the first substrate 10
A wedge having an asymmetrical shape with respect to the contact interface between the first substrate 10 and the second substrate 20 is inserted into the contact interface at the end of the bonded substrate 30. A method of inserting a wedge having a different hardness from a portion abutting on the end of the bonded substrate 30, inserting a symmetric or asymmetric wedge at a contact interface between the first substrate 10 and the second substrate 20,
A method of vibrating the wedge in a direction (asymmetrical direction) that is not perpendicular to the contact interface is preferable.

As a method of applying an “asymmetrical force” to the first substrate 10 and the second substrate 20, for example, the structure of the substrate holding portion that holds the respective substrates 10 and 20 is changed to an asymmetric structure. There is also a method of varying the degree of warping of the end of the slab. If the end of the first substrate 10 receives a larger moment than the end of the second substrate 20 and bends, a desired crack can be generated.

Here, when the first force acting on the first substrate 10 and the second force acting on the second substrate 20 are made different, an appropriate separation starting portion 60 is formed. , First
And the second force are determined.

An appropriate separation start portion is a separation that provides a structure in which substantially only the porous layer is broken and the bonded substrate 30 can be separated into two substrates in the subsequent main separation step (FIG. 2E). This is the start.

More specifically, the appropriate separation start portion is, for example, a structure in which a part of the porous layer is exposed to the atmosphere outside the bonded substrate 30, and the surface of the first substrate, here, the insulating layer From the surface of the insulating layer 14 and the single-crystal Si layer 13
By forming a crack 7A passing through the porous layer.

FIG. 2D shows a state in which a portion at the end (outside) of the crack 7A is removed after or simultaneously with the formation of the crack 7A to form the separation start portion 60. FIG. As shown, it is not essential to remove the portion at the end (outside) of the crack 7A.

As described above, by forming the separation start portion 60, in the subsequent main separation step (FIG. 2E), the porous layer 12 is selectively broken to separate the bonded substrate 30 into two substrates. Therefore, generation of defects in the separation step can be effectively prevented.

Next, the step shown in FIG. 2E (main separation step)
Now, the bonded substrate 30 on which the separation start part 60 is formed
Is completely separated into two substrates at the portion of the porous layer 12.
Here, the separation of the bonded substrate 30 is performed by the separation start unit 60.
By starting the growth of cracks in the lateral direction along the porous layer 12. As a method for separation, for example, the following method is suitable. (1) Separation Method Using Fluid First, a bundled fluid (for example, a liquid such as water or a gas such as air or nitrogen) is jetted to the separation start portion 60 of the bonded substrate 30, whereby the separation start portion 60 is separated. The fluid penetrates into the surrounding porous layer 12 while destroying the surrounding porous layer 12 and gradually expanding the separation region (separated region), that is, the lateral crack. Here, when the fluid is jetted toward the end of the bonded substrate 30 while rotating the bonded substrate 30 having the separation starting portion 60, the crack growth starts when the fluid hits the separation starting portion 60. Is done. Therefore, it is not necessary to align the fluid with the separation start part 60 at the start of the main separation step. Thereafter, the separation is further performed, and the entire surface of the remaining porous layer 12 is destroyed.
0 is completely separated. At this time, for example, it is preferable to rotate the bonded substrate 30 in the plane to change the position where the fluid is injected into the bonded substrate 30 to perform the separation.

When a fluid is used, a closed space surrounding the separation start portion is formed by a sealing member such as an O-ring, instead of the above-described method using a fluid jet, and the space is filled with the fluid. By filling and pressurizing the fluid, a method of growing a crack and injecting the fluid into the crack, that is, a method using a so-called static pressure fluid may be used. (2) Separation Method Utilizing Solid Wedge A wedge (for example, a thin wedge made of resin or the like) is gently inserted into the separation start portion 60 at the end of the bonded substrate 30, and the two substrates are spread. The bonded substrate 30 is completely separated.

When the separation start portion 60 is formed using a wedge, the separation start portion 60 is formed (FIG. 2D).
In this separation step (FIG. 2E), two processes can be continuously performed using the same apparatus. (3) Separation Method by Peeling One surface of the bonded substrate 30 is fixed, and the other surface is pulled in the axial direction of the bonded substrate 30 using a flexible tape or the like, whereby the bonded substrate 30 is separated. It is completely separated at the porous layer 12. At this time, at the start of separation, the separation force is concentrated on the separation start unit 60,
Apply tensile force. (4) Separation Method by Shear Stress By fixing one surface of the bonded substrate 30 and applying a force to the other surface so as to move the other surface in the surface direction of the bonded substrate 30, shearing is performed. The bonded substrate 30 is completely separated at the portion of the porous layer 12 by the stress. In this method, it is preferable to form the separation start part 60 larger than when other methods are applied so that the separation is started from the separation start part 60.

As described above, after the separation start portion 60 is formed, the separation process (main separation process) is started from the separation start portion 60, so that the bonded substrate 30 is substantially only a portion of the porous layer. The single-crystal Si layer 13, the insulating layer 14, the second substrate 20, the single-crystal Si substrate 1
1, and it is possible to prevent the interface between the layers or the substrate from being broken and causing serious defects.

Here, in contrast to the preferred embodiment of the present invention, a case where a symmetrical force is applied to the first substrate 10 and the second substrate 20 when forming the separation start portion. ,
Alternatively, the first substrate 10 and the second substrate
Bonded substrate 3 while applying a symmetrical force to the substrate 3
The state of separation of the bonded substrate 30 when separating 0 is considered.

FIG. 3 is a schematic view showing a state in which a symmetrical force is applied to the first substrate 10 and the second substrate 20 constituting the bonded substrate.

As shown in FIG. 3, the first substrate 10 and the second
Force 902A, 9 symmetrical with respect to the close interface with substrate 20
When 02B acts on the first substrate 10 and the second substrate 20, respectively, the action point 901 on the outermost peripheral portion of the contact interface is:
Symmetrical tensile forces 903A and 903B act on the contact surface. Thus, the direction of the separation is substantially in the plane direction of the bonded substrate 30 (horizontal direction in the figure) as indicated by an arrow 904.

Therefore, the separation does not reach the porous layer 12 and the single-crystal Si layer 13 and the insulating layer (Si) whose structure is weak next to the porous layer 12 as shown by the arrow 905 in FIG.
Along the interface with the O ₂ layer 14 by a corresponding distance L. In this case, the single crystal Si layer 13 and the insulating layer (SiO 2
Since the portion separated along the interface with the layer 14 is not transferred to the second substrate 20 side, the length L portion and the end portion thereof are missing and become defects.

However, the interface between the single-crystal Si layer 13 and the insulating layer (SiO ₂ layer) 14 is structurally stronger than the porous layer 12, so that a lateral crack generated at the interface is formed on the substrate. It rarely reaches the center, and crosses the single-crystal Si layer 13 from the middle to reach the porous layer, and is mostly separated by the porous layer 12. If the distance L is long, the point where the crack reaches the porous layer may exceed 3 mm from the outer peripheral edge of the substrate.

On the other hand, according to the preferred embodiment of the present invention, as shown in FIG. 5, the first substrate 10 and the second substrate 20 By applying asymmetrical forces 906A and 906B to the close contact interface, asymmetrical forces 907A and 907B act on the close contact interface between the first substrate 10 and the second substrate 20.

As a result, as shown by the arrow 908, the crack can easily reach the porous layer 12.

FIG. 6 shows a cross section of the composite member after the completion of the preliminary separation step according to the embodiment of the present invention. A state in which a crack crossing the insulating layer 14 and the single-crystal Si layer 13 reaches the porous layer 12 from the action point 901 on the surface of the first member is illustrated. In addition, the part 6 located at the end (outside) of the crack
1 may be removed before the main separation step. According to the embodiment of the present invention, the distance of a crack extending along the interface between the single-crystal Si layer 13 and the insulating layer 14 (the symbol L in FIG. 4) can be reduced to zero or extremely short. Specifically, the point at which the crack reaches the porous layer can be made within 3 mm, more preferably within 2 mm from the outer peripheral edge of the substrate at a high yield.

In the separation step (main separation step) shown in FIG. 2E, the separated first substrate 10 ′ is replaced with a single-crystal Si substrate 11.
It has a structure having the porous layer 12b thereon. On the other hand, the second substrate 20 ′ after separation has a porous Si layer 12 c / single-crystal Si
A layered structure of layer 13b / insulating layer 14b / single-crystal Si substrate 20 is obtained.

That is, the single crystal Si layer 13 and the insulating layer 14 on the porous layer 12 of the first substrate are
To the substrate. Here, the porous layer 12
Is an example of a separation layer, a single-crystal Si layer 13 and an insulating layer 14
Is an example of a transfer layer (surface layer) transferred from the first substrate to the second substrate.

In the step shown in FIG. 2F, if necessary, the porous layer 12c on the surface of the separated second substrate 20 is selectively removed. Thereby, as shown in FIG. 2F, a laminated structure of single crystal Si layer 13b / insulating layer 14b / single crystal Si substrate 20, that is, SOI having SOI layer (thin film) 13b
The substrate 50 is obtained.

In the step shown in FIG. 2G, if necessary, the porous layer 12b on the single-crystal Si substrate 11 of the separated first substrate 10 'is selectively removed by etching or the like. The single crystal Si substrate 11 thus obtained is again
For forming the first substrate 10 or the second substrate 20
Can be used as

As described above, according to the preferred embodiment of the present invention, an asymmetrical force is applied to the end of the bonded substrate with respect to the contact interface between the first substrate and the second substrate. Forming a separation start portion having a crack reaching the separation layer,
By performing the separation from the separation start portion, the porous layer can be selectively destroyed, so that the occurrence of serious defects can be prevented.

Next, a description will be given of a processing apparatus suitably used for performing the step of forming a separation start portion (preliminary separation step) according to the present invention.

[First Processing Apparatus] FIG. 7 is a diagram schematically showing a configuration of a first processing apparatus suitable for performing a preliminary separation step. A processing apparatus 200 illustrated in FIG. 7 includes a support base 201 having a support portion 203 that supports the bonded substrate 30,
An elastic body 202 for pressing the bonded substrate 30 against the support portion 203, a wedge 210, a drive shaft 211 with a rack for reciprocating the wedge 210, a guide member 212 for guiding the drive shaft 211, and a drive shaft And a motor (drive unit) 213 having a pinion gear for applying a driving force to the motor 211 to reciprocate.

When performing the preliminary separation step, the motor 21
3 is rotated forward, and the wedge 210 is inserted into the end of the bonded substrate 30 by a predetermined amount. On the other hand, when the wedge 210 is retracted, the motor 213 may be reversed.

FIG. 8 is an enlarged view of a part of FIG. The wedge 210 having an asymmetric structure has a structure in which an asymmetrical force is applied to the first substrate 10 and the second substrate 20 with respect to the close interface between the first substrate 10 and the second substrate. (The inclination θ1 on the side contacting the first substrate 10 is larger than the inclination θ2 on the side contacting the second substrate 20). This asymmetric structure is a structure in which a crack is generated from the exposed portion of the first substrate 10 toward the porous layer inside the first substrate 10, and an appropriate separation start portion can be formed.

FIG. 9 is a diagram schematically showing a state in which the wedge 210 is inserted into the end of the bonded substrate 30. Wedge 210
Has an asymmetric structure, so that the first substrate 10 and the second substrate 20 receive an asymmetric force with respect to the close contact interface. In FIG. 9, the crack at the separation start portion is drawn in a macroscopic manner. In actuality, as described above, the crack that traverses the transfer layer and reaches the separation layer, and the crack in the separation layer or above or below the separation layer therefrom. In the present separation step, including a lateral crack generated at the side interface, it is preferable to apply a solid wedge 210 ′ having a symmetrical structure as shown in FIG.
In this case, the processing apparatus shown in FIG. 7 is applied to the preliminary separation step, and the processing apparatus shown in FIG. 10 (the processing apparatus in which the wedge 210 of the processing apparatus shown in FIG. 7 is replaced with a wedge 210 ′) is used for the main separation step. Just apply.

[Second Processing Apparatus] FIG. 11 is a diagram schematically showing a configuration of a second processing apparatus suitable for performing a preliminary separation step. The processing apparatus 300 shown in FIG. 11 includes a support 201 having a support 203 for supporting the bonded substrate 30.
An elastic body 202 for pressing the bonded substrate 30 against the support 203, a wedge 220, a drive shaft 211 with a rack for reciprocating the wedge 220, and a guide member 212 for guiding the drive shaft 211; And a motor 213 having a pinion gear for reciprocating by applying a driving force to the driving shaft 211.

When performing the preliminary separation step, the motor 21
3, the wedge 220 is inserted into the end of the bonded substrate 30 by a predetermined amount. On the other hand, when retracting the wedge 220, the motor 213 may be rotated in the reverse direction.

FIG. 12 is an enlarged view of a part of FIG.
The wedge 220 having the asymmetric structure has a first structure as a structure for applying an asymmetric force to the first substrate 10 and the second substrate 20 with respect to the contact interface between the first substrate 10 and the second substrate.
And two contact surfaces that respectively contact the second substrates 10 and 20, and a second contact surface that contacts the second substrate 20 with respect to the first contact surface that contacts the first substrate 10. It has a structure in which the contact surface is receded by the length D. This asymmetric structure causes a crack from the exposed portion of the first substrate 10 toward the porous layer therein, thereby forming an appropriate separation start portion at the end of the bonded substrate 30. It is a structure that can be done.

FIG. 13 shows a state in which the wedge 220 is
It is a figure which shows a mode that it inserted in the edge part of No. 1 typically. Wedge 22
0 has an asymmetric structure, so that the first substrate 10 and the second substrate
The substrate 20 receives an asymmetric force with respect to the close interface. In FIG. 13, the crack at the separation start portion is drawn macroscopically, and in actuality, as described above, the crack that traverses the transfer layer and reaches the separation layer, and from there, within the separation layer or above or below the separation layer. In the present separation step, which includes a lateral crack generated at the side interface, it is preferable to apply a wedge 210 ′ having a symmetric structure, as shown in FIG. In this case, the processing apparatus shown in FIG. 11 is applied to the preliminary separation step, and the processing apparatus shown in FIG. 10 (the processing apparatus in which the wedge 220 of the processing apparatus shown in FIG. 11 is replaced with a wedge 210 ′) is applied to the main separation step. I just need.

[Third Processing Apparatus] FIG. 14 is a diagram schematically showing a configuration of a third processing apparatus suitable for performing the preliminary separation step. A processing apparatus 400 illustrated in FIG. 14 includes a support 201 having a support 203 that supports the bonded substrate 30.
An elastic body 202 for pressing the bonded substrate 30 against the support portion 203, a wedge 230, a drive shaft 211 with a rack for reciprocating the wedge 230, and a guide member 212 for guiding the drive shaft 211; And a motor 213 having a pinion gear for reciprocating by applying a driving force to the driving shaft 211.

When performing the preliminary separation step, the motor 21
3 is rotated forward, and a wedge 230 is inserted into the end of the bonded substrate 30 by a predetermined amount. On the other hand, when retracting the wedge 230, the motor 213 may be rotated in the reverse direction.

FIG. 15 is an enlarged view of a part of FIG.
The wedge 230 having the asymmetric structure has a structure for applying an asymmetric force to the first substrate 10 and the second substrate 20 with respect to the close contact interface between the first substrate 10 and the second substrate. Specifically, the wedge 230 is connected to the first substrate 10 in contact with the first substrate 10.
The first contact member 230a includes a contact member 230a and a second contact member 230b that contacts the second substrate 20.
It has a higher hardness than the contact member 230b. Typically, for example, the first contact member 230a is formed of a rigid body, and the second contact member 230b is formed of an elastic body (for example, rubber).
It consists of. Thereby, an appropriate separation start portion can be formed at the end of the bonded substrate 30.

FIG. 16 shows a state in which the wedge 230 is
It is a figure which shows a mode that it inserted in the edge part of No. 1 typically. Wedge 23
0 has an asymmetric structure, so that the first substrate 10 and the second substrate
The substrate 20 receives an asymmetric force with respect to the close interface. In FIG. 16, the crack at the separation start portion is drawn macroscopically, and in actuality, as described above, the crack that traverses the transfer layer and reaches the separation layer, and the crack in the separation layer or above or below the separation layer therefrom. In the present separation step, which includes a lateral crack generated at the side interface, it is preferable to apply a wedge 210 ′ having a symmetric structure, as shown in FIG. In this case, the processing apparatus shown in FIG. 14 is applied to the preliminary separation step, and the processing apparatus shown in FIG. 10 (the processing apparatus in which the wedge 230 of the processing apparatus shown in FIG. 14 is replaced by the wedge 210 ′) is applied to the main separation step. I just need.

[Fourth Processing Apparatus] FIG. 17 is a diagram schematically showing a configuration of a fourth processing apparatus suitable for performing the preliminary separation step. The processing apparatus 500 shown in FIG. 17 includes a support 201 having a support 203 for supporting the bonded substrate 30.
An elastic body 202 for pressing the bonded substrate 30 against the support portion 203; a wedge 240; a drive shaft 211 ′ with a rack for reciprocating the wedge 240; and a drive shaft 211 ′.
212, a motor 213 having a pinion gear for reciprocating by applying a driving force to the drive shaft 211 ', and a wedge 240 at the close contact interface between the first substrate 10 and the second substrate 20. The vibrator 250 includes a vibrator 250 that vibrates in an asymmetrical direction, and a connecting member 241 that connects one end of the vibrator 250 to the wedge 240.

The vibrator 250 generates vibration in an asymmetrical direction with respect to the contact interface between the first substrate 10 and the second substrate. As the vibrator 250, for example, an element (for example, a piezoelectric element) that converts an electric signal into mechanical vibration energy
Is preferred.

When performing the preliminary separation step, the motor 21
3 is rotated forward, and a wedge 240 is inserted into the end of the bonded substrate 30 by a predetermined amount. On the other hand, when the wedge 240 is retracted, the motor 213 may be reversed.

FIG. 18 is an enlarged view of a part of FIG.
The wedge 240 having an asymmetric structure is provided with a vibrator 250 shown in FIG.
As a result, vibration in an asymmetrical direction is applied to the contact interface between the first substrate 10 and the second substrate. Thus, an asymmetric force is applied to the first substrate 10 and the second substrate 20 with respect to the close interface. More specifically, the portion of the first substrate 10 that comes into contact with the wedge due to this vibration is outside the second substrate 20, so that the moment received by the substrate 10 is
The moment received by the substrate 20 is larger than that of the substrate 10.
Is larger than that at the end of the substrate 20. Thereby, a crack is generated from the exposed portion of the first substrate 10 toward the porous layer inside the first substrate 10, and an appropriate separation start portion can be formed at the end of the bonded substrate 30.

FIG. 19 shows a state in which the wedge 240 is
It is a figure which shows a mode that it inserted in the edge part of No. 1 typically. Wedge 24
Since 0 vibrates in an asymmetric direction, the first substrate 10 and the second substrate 20 receive an asymmetric force with respect to the close contact interface. In FIG. 13, the crack at the separation start portion is drawn macroscopically, and in actuality, as described above, the crack that traverses the transfer layer and reaches the separation layer, and from there, within the separation layer or above or below the separation layer. And lateral cracks at the side interface.

If the vibrator 250 of this device is stopped, this device can be preferably applied to the main separation step.

[Fifth Processing Apparatus] FIG. 20 is a diagram schematically showing a configuration of a fifth processing apparatus suitable for carrying out the present separation step of the present invention. The processing apparatus 600 includes the bonded substrate 3
0, a pair of substrate holding units 103 and 104, a rotation shaft 101 connected to one substrate holding unit 103 and rotatably supported, and a position between the substrate holding unit 103 and the substrate holding unit 104. An actuator (for example, an air cylinder) 108 connected to the rotation shaft 101 for adjusting the distance and pressing the bonded substrate 30, and a rotation connected to the other substrate holding unit 104 and rotatably supported. The shaft 102, a rotation source (motor) 105 for rotating the rotating shaft 102, an injection nozzle 106 for driving a fluid into the bonded substrate 30, and a relative positional relationship between the bonded substrate 30 and the injection nozzle 106 are adjusted. And a driving robot 107 for performing the operation.

As the fluid, for example, a liquid such as water or a gas such as air or nitrogen can be used. An apparatus that uses water as a fluid is generally called a water jet apparatus.
The diameter of the injection nozzle 106 is preferably, for example, about 0.1 mm.

The injection nozzle 106 is opposed to the bonded substrate, and the driving robot 107 is driven to drive the first substrate 10 and the first substrate 10 from the vicinity immediately above the close contact interface between the first substrate 10 and the second substrate 20. The injection nozzle 106 is arranged at a position deviated from. In this state, by ejecting a fluid from the ejection nozzle 106, an external force symmetric or asymmetric with respect to the contact interface between the first substrate 10 and the second substrate 20 acts on the end of the bonded substrate 30. Let it. Thereby, a crack is generated in the porous layer, and the crack can be grown.

Here, as a method of applying an asymmetric force to the end of the bonded substrate 30 with respect to the contact interface, another method can be adopted. For example, in the example shown in FIG. 20, the fluid is ejected in parallel to the contact interface, but the fluid is ejected toward the first substrate by being inclined with respect to the contact interface, and the fluid is ejected toward the first substrate. It can cause cracks to grow.

[Sixth Processing Apparatus] FIG. 21 is a diagram schematically showing a configuration of a sixth processing apparatus suitable for performing the preliminary separation step or the main separation step of the present invention.

The processing apparatus 700 shown in FIG. 21 has an asymmetric structure having a pair of substrate holders 113 and 114 for rotatably holding a bonded substrate and a warp correcting member 115 connected to one of the substrate holders 114. And a substrate holding mechanism. This asymmetric structure of the substrate holding mechanism applies an asymmetric force to the end of the bonded substrate with respect to the contact interface.

The substrate 20 is depressurized and adsorbed to the substrate holder 114 via the warp correcting member 115, and the substrate 10 is adsorbed to the substrate holder 113 under reduced pressure. Then, the substrate holding unit 114
When the substrate holding unit 113 (or the substrate holding unit 113) is rotated, the bonded substrate and the substrate holding unit 113 (or the substrate holding unit 114) rotate together.

The processing device 700 is used as follows. First, the bonded substrates are sandwiched and held by the substrate holding units 113 and 114. Then, the bonded substrate is stopped without rotating, and a fluid 117 such as pure water, air, or nitrogen is jetted from the injection nozzle 106 toward the contact interface of the bonded substrate and the vicinity thereof. At this time, the second substrate 20 is prevented from warping upward in the drawing by the plate-shaped warp correcting member 115. On the other hand, since there is no warp correcting member on the first substrate 10 side, the position of the outermost peripheral end of the member supporting the substrate is located inside that of the second substrate 20. Thus, the end of the first substrate 10 is more easily warped than the second substrate 20.

In such a state, when the fluid 117 is sprayed on the concave portions formed by the chamfered portions of the first and second substrates, the ends of both substrates receive a separating force from the fluid. Become. Thereby, a crack is generated from the surface of the first substrate 10 to the separation layer as shown in FIG. 6 and the like due to the action of the force as shown in FIG.

Thereafter, the substrate holding unit 114 is rotated while the fluid 117 is continuously jetted. As a result, the bonded substrates are gradually separated by the fluid 117 while being rotated. Here, the pressure applied by the compressor that supplies the fluid to the injection nozzle 106 is adjusted so that the bonded substrate is completely separated when the bonded substrate has rotated one or more rotations. In this separation process, the cracks spiral along the separation layer from outside the substrate toward the center.

When the two substrates are completely separated, the ejection of the fluid is stopped.

[Seventh Processing Apparatus] FIG. 22 is a diagram schematically showing a configuration of a seventh processing apparatus suitable for performing the preliminary separation step or the main separation step.

A processing apparatus 800 shown in FIG. 22 is connected to a pair of substrate holders 113 and 114 for rotatably holding a bonded substrate and one of the substrate holders 114, and sucks the substrate 20 only at an end. Recessed warp correcting member 1
And an asymmetric substrate holding mechanism having 16.
Reference numeral 118 denotes a concave portion (space). This asymmetric structure of the substrate holding mechanism applies an asymmetric force to the end of the bonded substrate with respect to the contact interface.

The substrate 20 is sucked under reduced pressure at the end of the suction member 115, and the substrate 10 is sucked under reduced pressure at the substrate holding unit 113. Then, the substrate holding unit 114 (or the substrate holding unit 11)
When 3) is rotated, the bonded substrate and the substrate holder 113 are rotated.
(Or the substrate holder 114) rotate together.

The operation of this device is the same as that of the device shown in FIG.

[Eighth Processing Apparatus] FIG. 23 is a diagram schematically showing a configuration of an eighth processing apparatus suitable for performing the preliminary separation step or the main separation step. The processing apparatus 900 includes an asymmetric substrate holding mechanism. The asymmetric structure of the substrate holding mechanism applies an asymmetric force to an end portion of the bonded substrate with respect to the contact interface.

The processing apparatus 900 shown in FIG.
1 and an upper lid 122, and a space 123 for accommodating the bonded substrate and another space 124 are formed therein.

In one space 123, a fluid supply tube 125 is provided.
However, a fluid supply tube 126 communicates with the other space 124, and independently supplies fluid at a desired pressure. Inside the processing apparatus 900, a sheet-like separating seal member 127 made of an elastic material such as rubber is attached.
This separates the space 123 from the space 124. Top lid 1
In the space 124 on the 22 side, an O-ring 12 having a hollow inside is provided.
8 are provided. The sealant 127 also functions as a holding section for the substrate 10.

The lower lid 121 is provided with a substrate holding portion 129 for holding the substrate 20, and the substrate holding portion 129 has a plurality of suction holes 130 for suction under reduced pressure.
An O-ring 131 for vacuum sealing is attached to the periphery of the substrate holding unit 129.

The processing apparatus 900 is used as follows. First, the upper and lower lids 121 and 122 are opened, and the bonded substrate is placed on the substrate holding part 129 and is sucked through the suction hole 130. Next, the upper and lower lids 121 and 122 are closed to seal the space 123, and pressurized fluid is supplied from the fluid supply tube 125 into the space 123. A pressurized fluid is supplied from the fluid supply tube 126 into the space 124.

Here, the pressure in the space 123 is made higher than the pressure in the space 124. Since the upper substrate 10 constituting the bonded substrate is in close contact with the sealing material 127 so as to be movable upward, when the static pressure is applied to the end of the substrate 10 by the fluid, as shown in FIG. Due to the action of the force, the end of the substrate 10 warps upward. As a result, cracks are generated from the surface of the first substrate 10 to the separation layer as shown in FIG.

Thereafter, when the static pressure is continuously applied using the fluid, the bonded substrate is completely separated.

FIG. 24 is a schematic plan view showing an example of the first substrate after separation of the composite member according to the embodiment of the present invention.

Excluding the separation start section 60, the first substrate 11
The residual porous layer 12b having a uniform thickness over a large area remains on the separation surface side. If the position of the hemispherical separation start part 60 is within 3 mm, more preferably within 2 mm from the outermost end of the substrate, a good SOI substrate can be obtained.

According to the embodiment of the present invention, the position of the crack reaching the separation layer is set within 3 mm from the outermost end of the substrate.
More preferably, it can be stably expressed within 2 mm.

In the present invention, it is preferable to perform the preliminary separation step without rotating the bonded substrate so as not to unintentionally increase the area of the separation start portion 60.

Then, after the pre-separation step, a fluid is jetted toward the end of the bonded substrate while rotating the bonded substrate. The crack does not grow until the fluid hits near the separation start part 60, but when the fluid hits near the separation start part 60, the process shifts to the main separation step. In the present separation step using a fluid, the bonded substrate 30 is
It is preferable to carry out this separation step by growing the crack spirally from the outer peripheral side toward the center while rotating it one or more times, more preferably two or more times. Thereby, the warpage of the substrate during the main separation step can be suppressed, and the cracking of the substrate itself can be reliably prevented.

Here, an embodiment of a method of manufacturing a thin film using an ion implantation method will be described with reference to FIGS. 25A to 25E.

First, a substrate such as a single crystal silicon wafer is prepared. Preferably, a substrate in which the single crystal semiconductor layer 13 is epitaxially grown on a mirror wafer is used.

Next, the substrate 1 is subjected to a heat treatment in an oxidizing atmosphere.
An insulating layer 14 such as silicon oxide is formed on the surface of the substrate 1.

By the linear ion implantation method or the plasma immersion ion implantation method, ions are implanted into the substrate 11 through the surface of the substrate 11 on which the insulating layer 14 is formed. Here, the energy at the time of ion implantation is controlled according to the thickness of the transfer layer, and the implanted particles are implanted so as to have a peak concentration at a depth corresponding to the thickness of the transfer layer.

The layered portion where the implanted particles are distributed at a high concentration functions as the separation layer 4 because defects and stress are generated by the implanted ions.

In this manner, a first member having the insulating layer 14 and the single-crystal semiconductor layer 13 serving as the transfer layer, and the separation layer 4 formed by ion implantation thereunder is manufactured (FIG. 25A).

Next, a second member 20 such as a quartz glass or single crystal silicon wafer is prepared, and an insulating layer such as silicon oxide is formed on the surface thereof as required.

Next, the first member and the second member 20 are brought into close contact with each other at room temperature, and they are bonded to each other. Here, it is also preferable to perform a heat treatment as needed to increase the bonding strength. Thus, the composite member shown in FIG. 25B is obtained.

Next, the above-mentioned asymmetrical external force is applied to the composite member to cause the insulating layer 14 which is a transfer layer from the surface of the first member.
And a crack 7 reaching the separation layer 4 through the single crystal semiconductor layer 13
Form A (FIG. 25C).

Then, a separating force is further applied to cause a crack 7B to grow along the separating layer 4 in the lateral direction in the figure (FIG. 25D).

In this manner, as shown in FIG. 25E, the composite member is completely separated, and the insulating layer 14 and the single crystal semiconductor layer 13 are transferred to the second member.

Through the above steps, a thin film (single-crystal semiconductor layer 13) serving as an SOI layer can be manufactured.

Hereinafter, preferred embodiments of the present invention will be described.

[First Embodiment] This embodiment is an example in which the first processing apparatus 200 and the fifth processing apparatus 600 are applied to the manufacturing process of an SOI substrate.

First, in order to form the first substrate 10, a P-type (or N-type) single-crystal Si substrate 11 having a specific resistance of 0.01 Ω · cm is prepared. On the other hand, a two-stage anodizing treatment was performed in an HF solution, and a porous Si layer 12 composed of two porous layers having different porosity was formed on the surface thereof (FIG. 2A). The anodizing conditions at this time are as follows.

<First Anodizing Condition> Current density: 7 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1:
1: 1 Treatment time: 5 (min) Porous Si thickness: 4.5 (μm) <Second-stage anodizing condition> Current density: 30 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1:
1: 1 treatment time: 10 (sec) Porous Si thickness: 0.2 (μm) Thus, on the surface side of the first substrate, a first-stage low-current, low-porosity first porous layer Was formed, and a second porous layer thinner and more porous than the first porous layer was formed under the first porous layer at the second stage of high current.

The thickness of the first porous layer is not limited to the above example, but is preferably, for example, several hundred μm to 0.1 μm. Also, the thickness of the second porous layer is not limited to the above example, and can be appropriately changed according to the conditions of the subsequent separation step and the like.

A second porous layer is formed within the second porous layer so that the first porous layer has a porosity suitable for forming a high quality epitaxial Si layer 13. The above conditions were determined so that the porosity was such that a crack was formed in a portion very close to the interface with the first porous layer.

The porous layer 12 may have a one-layer structure or a three-layer structure.
It may have a structure of more than layers.

Next, the substrate was oxidized at 400 ° C. for one hour in an oxygen atmosphere. By this oxidation treatment, the wall surfaces of the pores of the porous layer 12 were covered with a thermal oxide film while maintaining the inside of the pore walls of the porous layer as single-crystal Si.

Next, the CVD (Chemic
al Vapor Deposition) method by 0.3μm thick single crystal S
The i-layer 13 was grown epitaxially (FIG. 2B). The growth conditions at this time are as follows. Prior to the epitaxial growth, the porous Si layer 12 was added to hydrogen gas at a high temperature.
Is exposed, the holes on the surface are filled by migration of Si atoms, and the surface becomes flat.

<Epitaxial Growth Conditions> Source gas: SiH ₂ Cl ₂ / H ₂ Gas flow rate: 0.5 / 180 (l / min) Gas pressure: 80 (Torr) Temperature: 950 (° C.) Growth rate: 0.30 ( (μm / min) Next, a 200 nm thick SiO ₂ layer 14 was formed on the surface of the single crystal Si layer 13 epitaxially grown by thermal oxidation (FIG. 2B). Thus, a first substrate 10 is obtained.

Next, a separately prepared Si substrate (second substrate) 20 of the same size as the first substrate 10 and the first substrate 1
The heat treatment was performed at 1180 ° C. for 5 minutes in an oxidizing atmosphere by closely contacting the surface of the SiO ₂ layer 14 with the center position of each substrate. This results in FIG. 2C
The bonded substrate 30 shown in FIG. Actually, the surface of the composite member was covered with the oxide film by the heat treatment in the oxidizing atmosphere.

Next, as shown in FIG. 7, the outer peripheral portion of the bonded substrate 30 was supported by the support portion 203 of the processing apparatus 200. At this time, the separation start portion formed on the bonded substrate 30 was opposed to the solid wedge 210.

Subsequently, the motor 213 is driven to drive the wedge 210
Is moved in parallel to the adhesive interface of the bonded substrate 30,
A wedge 210 is attached to the separation start portion of the bonded substrate 30 by about 1.5.
mm. As a result, a crack reaching the porous layer 12 as shown in FIG. 6 is formed in the bonded substrate 30, and an end portion is cut off from the crack, and a substantially semicircular separation start as shown in FIG. The part 60 was formed (FIG. 2D).

Here, a resin wedge 210 made of polytetrafluoroethylene (PTFE) was employed. The wedge 210 employed here has an angle θ1 of 20 degrees between the contact surface where the wedge 210 contacts the first substrate 10 and the contact interface, and the wedge 210
Has an angle θ2 of 10 degrees between the contact surface contacting the second substrate 20 and the contact interface. That is, the relationship of 0 ≦ θ2 <θ1 was satisfied (see FIG. 8 or 9).

Next, the bonded substrate 30 was held by the substrate holding units 103 and 104 of the processing apparatus 600 shown in FIG. At this time, the bonded substrate 30 was positioned such that the separation start portion was opposed to the injection nozzle 106.

Next, the injection nozzle 10 having a diameter of 0.1 mm was used.
From 6, a fluid (in this case, water) at a pressure of 400 kgf / cm ² was injected toward the separation start part to start separation. Then, after that, the separation is advanced while rotating the bonded substrate 30, and the crack is spirally formed along the second porous layer near the interface between the first porous layer and the second porous layer. Grow inside. The crack reached the center of the bonded substrate 30, and the bonded substrate 30 could be completely separated into two substrates at the porous layer 12 (FIG. 2E).

Next, the residual porous layer 12b remaining on the surface of the second substrate 20 'after the separation was treated with hydrofluoric acid having an HF concentration of 49% by weight, hydrogen peroxide solution having an H ₂ O ₂ concentration of 30% by weight, and water. 2 was selectively etched using the mixed solution of
F). Thus, an SOI substrate as shown in FIG. 2F was obtained. The outer peripheral edge of the transferred single-crystal Si layer 13b was present within 2 mm from the outer peripheral edge of the substrate 20 over the entire periphery, and was in close contact with the substrate 20 via the insulating layer 14b.

[0140] Then, the single-crystal Si substrate 11 remaining on the remaining porous layer 12b of HF concentration of 49 wt% hydrofluoric acid and _{H 2} O ₂
The mixture was selectively etched using a mixed solution of a hydrogen peroxide solution having a concentration of 30% by weight and water as an etchant (FIG. 2G).

[Second Embodiment] This embodiment is an example in which the second processing apparatus 300 and the fifth processing apparatus 600 are applied to the manufacturing process of an SOI substrate.

The steps up to the production of the bonded substrate 30 were performed in the same manner as in the first embodiment.

Next, as shown in FIG. 11, the outer peripheral portion of the bonded substrate 30 was supported by the support 203 of the processing apparatus 300. At this time, the separation start portion formed on the bonded substrate 30 was opposed to the wedge 220.

Next, the motor 213 is driven to drive the wedge 220
Is moved in parallel to the adhesive interface of the bonded substrate 30,
A wedge 220 is attached to the separation start portion of the bonded substrate 30 by about 1.5.
mm.

Here, a wedge 220 made of PTFE is employed.
Further, the wedge 220 employed here has a contact surface where the wedge 220 contacts the second substrate 20 with respect to the first contact surface where the wedge 220 contacts the first substrate 10 is 0.5 mm ( That is, D
= 0.5 mm> 0) (FIG. 12)
Or see FIG. 13). As a result, a crack reaching the porous layer 12 as shown in FIG. 6 is formed in the bonded substrate 30, and the end (outside) of the crack is cut off, and a substantially semicircular shape as shown in FIG. 24 is formed. Was formed (FIG. 2D).

Next, as in the first embodiment, FIG.
The main separation was performed using the processing apparatus 600 shown in FIG. Further, in the same manner as in the first embodiment, the single crystal S
The i-substrate was regenerated.

[Third Embodiment] This embodiment is an example in which the third processing apparatus 400 and the fifth processing apparatus 600 are applied to the manufacturing process of an SOI substrate.

The steps up to the production of the bonded substrate 30 were performed in the same manner as in the first embodiment.

Next, as shown in FIG. 14, the outer peripheral portion of the bonded substrate 30 was supported by the support portion 203 of the processing apparatus 400. At this time, the separation start portion formed on the bonded substrate 30 was opposed to the wedge 230.

Next, the motor 213 is driven to drive the wedge 230
Is moved in parallel to the adhesive interface of the bonded substrate 30,
A wedge 230 is attached to the separation start portion of the bonded substrate 30 by about 1.5.
mm.

The wedge 230 employed here is the first substrate 1
The first member 230a in contact with 0 has higher hardness than the second member 230b in contact with the second substrate 20. More specifically, a wedge 230 is used in which the first member 230a is made of PEEK and the second member 230b is made of rubber (see FIG. 15 or 16).

As a result, a crack reaching the porous layer 12 as shown in FIG. 6 is formed in the bonded substrate 30, and an end portion is cut off from the crack, so that a substantially rectangular portion as shown in FIG. A semicircular separation start portion 60 is formed (FIG. 2).
D).

Next, in the same manner as in the first embodiment, FIG.
The main separation was performed using the processing apparatus 600 shown in FIG. Further, in the same manner as in the first embodiment, the single crystal S
The i-substrate was regenerated.

[Fourth Embodiment] This embodiment is an example in which the fourth processing apparatus 500 and the fifth processing apparatus 600 are applied to the manufacturing process of an SOI substrate.

The steps up to the production of the bonded substrate 30 were performed in the same manner as in the first embodiment.

Next, as shown in FIG. 17, the outer peripheral portion of the bonded substrate 30 was supported by the support portion 203 of the processing apparatus 500. At this time, the separation start portion formed on the bonded substrate 30 was opposed to the wedge 240.

Next, the motor 213 is driven to drive the wedge 240
Is moved in parallel to the adhesive interface of the bonded substrate 30,
While the wedge 240 is being vibrated, about 1.
Only 5 mm was inserted. As a result, a crack reaching the porous layer 12 as shown in FIG. 6 is formed in the bonded substrate 30, and an end portion of the crack is cut off.
(See FIG. 2D).

Next, as in the first embodiment, FIG.
The main separation was performed using the processing apparatus 600 shown in FIG. Further, in the same manner as in the first embodiment, the single crystal S
The i-substrate was regenerated.

[Fifth Embodiment] This embodiment is an example in which the first processing apparatus 200 and the fifth processing apparatus 600 are used in the manufacturing process of an SOI substrate.

The steps up to the formation of the separation start portion 60 on the bonded substrate 30 are the same as those in the first embodiment.

Next, the bonded substrate 30 was held and rotated in the processing apparatus 600 shown in FIG. 20, and a fluid having a pressure of 400 kgf / cm ² was jetted in the same manner as in the first embodiment.

After the fluid hits the vicinity of the rotating separation start portion 60, cracks grow spirally, and the bonded substrate 3
When reaching the center of 0, the bonded substrate 30 was completely separated into two substrates.

The subsequent processing is the same as in the first embodiment.

[Sixth Embodiment] This embodiment is an example in which the sixth processing apparatus 700 is used in the manufacturing process of an SOI substrate.

The steps up to the production of the bonded substrate 30 are the same as those of the first embodiment.

Next, the bonded substrate 30 is held in the processing apparatus 700 shown in FIG.
A fluid having a pressure of kgf / cm ² was ejected to warp the end of the substrate 10 downward to form a separation start portion.

Next, the pressure of the fluid was set to 400 kgf / cm
² Lower, then, by rotating the bonded substrate 30, the crack is grown in a spiral shape and was separated bonded substrate stack 30 to complete the two substrates.

The subsequent processing is the same as in the first embodiment.

According to the present invention, for example, a composite member such as a bonded substrate can be appropriately separated by a separation layer such as a porous layer.

[Brief description of the drawings]

FIG. 1A,

FIG. 1B,

FIG. 1C is a schematic diagram for explaining a method of separating a composite member according to a preferred embodiment of the present invention.

FIG. 2A is a schematic view illustrating a step of forming a porous layer in a method for manufacturing an SOI substrate according to a preferred embodiment of the present invention.

FIG. 2B is a schematic diagram for explaining a step of forming a single-crystal Si layer and an insulating layer in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 2C is a schematic diagram for explaining a bonding step in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 2D is a schematic diagram for explaining a formation step (preliminary separation step) of a separation start part in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 2E is a schematic diagram for explaining a separation step (main separation step) in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 2F is a schematic diagram for explaining the step of removing the porous layer on the second substrate side and the SOI substrate in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 2G is a schematic diagram for explaining the step of removing the porous layer on the first substrate side in the method for manufacturing an SOI substrate according to the preferred embodiment of the present invention.

FIG. 3 is a schematic diagram showing a state in which a symmetrical force is applied to a first substrate and a second substrate that constitute a bonded substrate.

FIG. 4 is a diagram schematically showing a defect that can be caused by a separation process.

FIG. 5 is a diagram showing a force acting on a bonded substrate when forming a separation start portion according to a preferred embodiment of the present invention.

FIG. 6 is a diagram schematically showing a cross section of a bonded substrate on which a separation start portion is formed by a processing apparatus according to a preferred embodiment of the present invention.

FIG. 7 is a diagram schematically showing a configuration of a first processing apparatus suitable for performing a preliminary separation step.

FIG. 8 is an enlarged view of a part of FIG. 7;

FIG. 9 is a view schematically showing a state in which a wedge is inserted into an end of a bonded substrate.

FIG. 10 is a diagram showing a wedge suitable for the separation step.

FIG. 11 is a diagram schematically showing a configuration of a second processing apparatus suitable for performing a preliminary separation step.

FIG. 12 is an enlarged view of a part of FIG. 11;

FIG. 13 is a diagram schematically showing a state in which a wedge is inserted into an end of a bonded substrate.

FIG. 14 is a diagram schematically showing a configuration of a third processing apparatus suitable for performing a preliminary separation step.

FIG. 15 is a partially enlarged view of FIG. 14;

FIG. 16 is a diagram schematically showing a state in which a wedge is inserted into an end of a bonded substrate.

FIG. 17 is a diagram schematically showing a configuration of a fourth processing apparatus suitable for performing a preliminary separation step.

18 is an enlarged view of a part of FIG.

FIG. 19 is a view schematically showing a state in which a wedge is inserted into an end of a bonded substrate.

FIG. 20 is a view schematically showing a configuration of a fifth processing apparatus suitable for performing the present separation step.

FIG. 21 is a view schematically showing a configuration of a sixth processing apparatus suitable for performing a preliminary separation step or a main separation step.

FIG. 22 is a view schematically showing a configuration of a seventh processing apparatus suitable for performing a preliminary separation step or a main separation step.

FIG. 23 is a view schematically showing a configuration of an eighth processing apparatus suitable for performing a preliminary separation step or a main separation step.

FIG. 24 is a schematic plan view showing an example of the first substrate after separation of the composite member according to the embodiment of the present invention.

FIG. 25A,

FIG. 25B,

FIG. 25C,

FIG. 25D,

FIG. 25E is a schematic diagram for explaining the method for manufacturing the thin film according to the preferred embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 first member 2 second member 3 substrate 4 separation layer 5 transfer layer 6 composite member 7A, 7B crack 8 asymmetric force 9 separation force 10 first substrate 20 second substrate 30 bonded substrate 50 SOI substrate 60 Separation start part 11 Single crystal Si substrate 12 Porous layer 13 Single crystal Si layer 14 Insulating layer (SiO ₂ layer) 100, 200, 300, 400, 500, 600 Processing device 101, 102 Rotation axis 103, 104 Substrate holding part 105 Rotation source (motor) 106 Injection nozzle 107 Driving robot 108 Actuator 201 Support base 202 Elastic body 203 Support part 210, 210 ', 220, 230, 240 Wedge 211, 211' Drive shaft with rack 212 Guide member 213 Motor 230a First member 230b Second member 241 Connecting member 250 Vibrator

Claims (45)

[Claims] 1. A composite member in which a first member having a separation layer and a transfer layer on the separation layer and a second member are in close contact with each other, and a composite member of the first member and the second member is A method of separating a composite member that separates at a position different from a contact interface, wherein an asymmetric force is applied to an end of the composite member with respect to the contact interface, whereby the first member is attached to the composite member. A separation method comprising: a preliminary separation step including a step of forming a crack extending from a surface through the transfer layer to the separation layer; and a main separation step including a step of growing the crack along the separation layer. 2. In the main separation step, the crack is grown substantially in or at the interface between the separation layers.
The separation method described in 1. 3. The method according to claim 1, wherein the transfer layer includes an insulating layer. 4. The method according to claim 1, wherein the transfer layer includes an insulating layer and a semiconductor layer. 5. The separation method according to claim 1, wherein the separation layer is a porous layer formed by anodization. 6. The separation method according to claim 1, wherein said separation layer is an implantation layer formed by ion implantation. 7. The pre-separation step, wherein at least one of a solid wedge and an asymmetric substrate holding mechanism is used to apply an asymmetric force to the end of the composite member with respect to the contact interface. Item 4. The separation method according to Item 1. 8. The separating method according to claim 7, wherein the wedge has a pair of asymmetric inclined contact surfaces. 9. The wedge has a first abutting surface abutting on the first member and a second abutting surface abutting on the second member. 8. The separation method according to claim 7, wherein an angle formed by the contact surface with the contact interface is larger than an angle formed by the second contact surface with the contact interface. 10. The separation method according to claim 7, wherein, in the preliminary separation step, the wedge is moved in parallel with a close interface and inserted into an end of the composite member. 11. The wedge has a first contact surface that contacts the first member and a second contact surface that contacts the second member. 8. The separation method according to claim 7, wherein said first contact surface has a structure in which said first contact surface comes into contact with said composite member before said second contact surface when inserted into said composite member. 12. The wedge has a first abutting member abutting on the first member and a second abutting member abutting on the second member. The separation method according to claim 7, wherein the contact member has a higher hardness than the second contact member. 13. The separation method according to claim 7, wherein the preliminary separation step applies an asymmetrical vibration to the wedge with respect to the close interface. 14. The method according to claim 7, wherein the wedge is made of resin. 15. The separation method according to claim 1, wherein in the main separation step, a fluid enters the crack to grow the crack. 16. The separation method according to claim 15, wherein the fluid is a static pressure fluid or a jet. 17. The separation according to claim 1, wherein in the preliminary separation step, the crack is formed without rotating the composite member, and in the main separation step, the crack is grown while rotating the composite member. Method. 18. The separation method according to claim 1, wherein in the preliminary separation step, the crack is formed while suppressing the warping of the second member from the warping of the first member. 19. The composite member according to claim 1, wherein in the preliminary separation step, the composite member is held by a substrate holding portion provided with a member that suppresses the warpage of the second member from the warpage of the first member. Separation method. 20. A method for producing a thin film, comprising the step of using the separation method according to claim 1 to transfer a transfer layer of the first member on the surface side of the separation layer to the second member. . 21. A step of bringing a first member having a separation layer and a transfer layer on the separation layer into close contact with a second member to form a composite member; A separating step of separating the composite member at a position different from the close contact interface with the member, wherein the separating step applies an asymmetric force to the close contact interface to the end of the composite member. A first step of forming a crack in the composite member from the surface of the first member to the separation layer through the transfer layer; and a second step of growing the crack along the separation layer. And a method for producing a thin film comprising: 22. The method according to claim 2, wherein in the second step, the crack is grown substantially in or at the interface between the separation layers.
2. The method for producing a thin film according to 1. 23. The transfer layer includes an insulating layer.
3. The method for producing a thin film according to item 1. 24. The method according to claim 21, wherein the transfer layer includes an insulating layer and a semiconductor layer. 25. The method according to claim 21, wherein the separation layer is a porous layer formed by anodization. 26. The method according to claim 21, wherein the separation layer is an implantation layer formed by ion implantation. 27. The first step, wherein at least one of an asymmetric solid wedge and an asymmetric substrate holding mechanism is used to apply an asymmetric force to the end of the composite member with respect to the contact interface. 22. The method for producing a thin film according to claim 21, which is performed. 28. The method according to claim 27, wherein the wedge has a pair of asymmetric inclined contact surfaces. 29. The wedge has a first contact surface that contacts the first member and a second contact surface that contacts the second member. 28. The method of manufacturing a thin film according to claim 27, wherein an angle between the contact surface and the contact interface is larger than an angle between the second contact surface and the contact interface. 30. The method according to claim 27, wherein, in the first step, the wedge is moved in parallel with a close interface and inserted into an end of the composite member. 31. The wedge has a first contact surface that contacts the first member and a second contact surface that contacts the second member. 28. The method of manufacturing a thin film according to claim 27, wherein the first contact surface contacts the composite member before the second contact surface when inserted into the composite member. 32. The wedge has a first abutting member abutting on the first member and a second abutting member abutting on the second member. 28. The method of manufacturing a thin film according to claim 27, wherein the contact member has a higher hardness than the second contact member. 33. The method according to claim 27, wherein in the first step, an asymmetrical vibration is applied to the wedge with respect to the close interface. 34. The method according to claim 27, wherein the wedge is made of resin. 35. The method of manufacturing a thin film according to claim 2, wherein in the second step, the crack is grown by injecting a fluid into the crack. 36. The method according to claim 35, wherein the fluid is a static pressure fluid or a jet. 37. A crack is formed without rotating the composite member in the first step, and the crack is grown while rotating the composite member in the second step.
3. The method for producing a thin film according to item 1. 38. The method according to claim 21, wherein, in the first step, the crack is formed while suppressing the warpage of the second member from the warpage of the first member. 39. The composite member according to claim 38, wherein, in the first step, the composite member is held by a substrate holding portion provided with a member for suppressing the warpage of the second member from the warpage of the first member. Production method of thin film. 40. The first member, comprising: forming a porous layer serving as the separation layer on a surface of a substrate; and forming a non-porous semiconductor layer and an insulating layer so as to cover the porous layer. 22. The method for producing a thin film according to claim 21, further comprising the step of: 41. The method according to claim 21, further comprising a step of forming the first member by implanting ions from a surface side of the substrate to form an ion implantation layer serving as the separation layer in the substrate. Method of manufacturing thin film. 42. The method according to claim 21, further comprising a step of heat-treating the composite member in an oxidizing atmosphere. 43. A step of heat-treating the composite member in an oxidizing atmosphere to form an oxide film on a surface of the composite member, wherein cracks extending from the surface of the first member to the separation layer are: 22. The method for producing a thin film according to claim 21, wherein the crack is a crack crossing the oxide film. 44. The thin film provided on an insulating surface
22. The method for producing a thin film according to claim 21, which is an SOI layer. 45. A composite member in which a first member having a separation layer and a transfer layer on the separation layer and a second member are in close contact with each other, and a composite member of the first member and the second member is formed. A separation device for a composite member that separates at a position different from the contact interface, wherein an asymmetrical force is applied to an end of the composite member with respect to the contact interface, whereby the first member A separation device comprising: a pre-separation mechanism having an asymmetric structure that forms a crack extending from a surface through the transfer layer to the separation layer; and a main separation mechanism that grows the crack along the separation layer.