JPH11195570A - Object separating device and method, and manufacture of semiconductor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for separating a porous layer from a substrate possessed of it. SOLUTION: A laminated substrate 101 possessed of a porous layer 101b is supported while being spun by substrate holders 108 and 109. High-pressure water of (jet of water) is jetted out at a high speed from a nozzle 112, and a jet of high-pressure water is inserted into the laminated substrate 101 so as to physically separate the laminated substrate 101 into two substrates. Thereafter, the substrate holder 109 is moved in the positive direction of an X-axis making a jet of water be inserted between the separated substrates, whereby the substrates are separated off from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for separating an object and a method for manufacturing a semiconductor substrate.

[0002]

2. Description of the Related Art As a substrate having a single crystal Si layer on an insulating layer, a substrate (SOI substrate) having an SOI (silicon on insulator) structure is known. Devices using this SOI substrate have a number of advantages that cannot be achieved with a normal Si substrate. The advantages include, for example, the following. (1) Dielectric separation is easy and suitable for high integration. (2) Excellent radiation resistance. (3) The stray capacitance is small, and the operation speed of the element can be increased. (4) No well step is required. (5) Latch-up can be prevented. (6) A complete depletion type field effect transistor can be formed by thinning.

[0003] Since the SOI structure has various advantages as described above, research on a forming method thereof has been advanced in recent decades.

As an SOI technique, SOS (silicon on s) is conventionally formed by forming Si on a single crystal sapphire substrate by heteroepitaxial growth by a CVD (chemical vapor deposition) method.
apphire) technology is known. Although this SOS technology has gained a reputation as the most mature SOI technology,
Practical due to large number of crystal defects due to lattice mismatch at the interface between the Si layer and the underlying sapphire substrate, mixing of aluminum constituting the sapphire substrate into the Si layer, cost of the substrate, delay in increasing the area, etc. Has not progressed.

Following SOS technology, SIMOX (separa
tion by ion implanted oxygen) technology has emerged. With respect to the SIMOX technology, various methods have been attempted with the aim of reducing crystal defects and reducing manufacturing costs. As this method, a method of implanting oxygen ions into a substrate to form a buried oxide layer, bonding two wafers with an oxide film interposed therebetween, and polishing or etching one of the wafers to form a thin single-crystal Si layer A method of leaving on an oxide film, furthermore, hydrogen ions are implanted at a predetermined depth from the surface of the Si substrate on which the oxide film is formed, and after bonding with the other substrate, a thin film is formed on the oxide film by heat treatment or the like. A method of removing the bonded substrate (the other substrate) while leaving the single crystal Si layer, or the like can be given.

The present applicant has disclosed a new SOI technique in Japanese Patent Application Laid-Open No. Hei 5-21338. According to this technique, a first substrate in which a non-porous single-crystal layer (SiO ₂ ) is formed on a single-crystal semiconductor substrate in which a porous layer is formed is separated from an insulating layer (Si).
O ₂ ) is applied to the second substrate, the two substrates are separated by a porous layer, and the non-porous single crystal layer is transferred to the second substrate. This technique has excellent thickness uniformity of the SOI layer, can reduce the crystal defect density of the SOI layer, has good surface flatness of the SOI layer,
Eliminates the need for expensive special equipment
It is excellent in that an SOI substrate having an SOI film in the range of about Å to 10 μm can be manufactured by the same manufacturing apparatus.

[0007] Further, the applicant of the present invention has disclosed Japanese Patent Application Laid-Open No. 7-30288.
In No. 9, after the first substrate and the second substrate are bonded to each other, the first substrate is separated from the second substrate without breaking, and then the separated surface of the first substrate is removed. A technique has been disclosed in which a porous layer is formed again after smoothing and reused. This technique has excellent advantages that the first substrate can be used without waste, so that the manufacturing cost can be greatly reduced and the manufacturing process is simple.

[0008]

In the above technique, when the two substrates are separated from each other, there is no damage to both substrates, and there is little contamination of the substrate and the manufacturing apparatus due to generation of particles. Is required.

The present invention has been made in view of the above circumstances, and has as its object to apply a separation apparatus and method suitable for separating a semiconductor substrate and other objects, and a method of manufacturing a semiconductor substrate.

[0010]

According to the present invention, there is provided an apparatus for separating an object, comprising: separating means for separating an object to be separated into at least two objects by using a bundle of fluid; And separating means for separating each object while injecting a fluid into the fluid.

In the above-described separation apparatus, the object to be separated is, for example, a plate-like object, and the separating means cuts the plate-like object in a plane direction and separates the object into two plate-like objects. preferable.

[0012] In the above separating apparatus, a pair of holding portions for holding the object so as to be sandwiched from both sides when separating the object and for holding each separated object even after the object is separated are provided. It is preferable to further provide.

In the above separating apparatus, it is preferable that the pair of holding portions hold the object while pressing the object when separating the object.

In the above-mentioned separating apparatus, it is preferable that the separating means separates the separated objects by widening an interval between the pair of holding parts after the objects are separated by the separating means.

[0015] In the above separating apparatus, it is preferable that the pair of holding portions have an adsorbing mechanism for adsorbing each separated object.

In the above separation apparatus, it is preferable that the suction mechanism includes a vacuum suction mechanism.

The above separating apparatus further comprises an ejecting section for ejecting a bundle of fluids, wherein the separating means separates an object to be separated by the fluid ejected from the ejecting section, and wherein the separating means comprises: It is preferable to separate the objects while injecting the fluid ejected from the ejection unit between the separated objects.

In the above separation apparatus, the object to be separated preferably has a fragile layer inside as a separation layer. The fragile layer is preferably, for example, a porous layer. Further, it is preferable that the fragile layer is, for example, a layer having microbubbles.

Another separation device according to the present invention is a separation device for separating an object, comprising: an ejection portion for ejecting a bundle of fluid; and a set of holding portions for holding the object. While ejecting a fluid from the ejecting unit toward the object while holding the object to be separated by the holding unit, the object is separated while the fluid is ejected from the ejecting unit toward between the separated objects. The one set of holding parts is moved so as to separate the separated substrates while ejecting.

In the above other separation apparatus, the object to be separated is, for example, plate-shaped, and the pair of holding portions may hold the object so as to sandwich the object from both sides when separating the object. preferable.

In the above another separating apparatus, it is preferable that the pair of holding units hold the object while pressing the object when separating the object.

In the above-mentioned other separating apparatus, it is preferable that the one set of holding units has a suction mechanism for sucking each separated object.

[0023] In the above other separation apparatus, it is preferable that the suction mechanism includes a vacuum suction mechanism.

The object to be separated preferably has a fragile layer inside as a layer for separation. The fragile layer is preferably, for example, a porous layer. Further, it is preferable that the fragile layer is, for example, a layer having microbubbles.

The separation method for separating an object according to the present invention comprises:
A separation step of injecting a bundle of fluid toward the object to be separated while separating the object into at least two objects, and a separation step of injecting a fluid between the separated objects and separating the objects from each other. It is characterized by including.

In the above-described separation method, the object to be separated is, for example, a plate-like object. In the separation step, the plate-like object may be cut in a plane direction and separated into two plate-like objects. preferable.

In the above separation method, it is preferable that, in the separation step, the object to be separated is held so as to be sandwiched from both sides.

In the above separation method, in the separating step, the separated substrates may be separated from each other by widening a distance between the two holding portions in a state where the separated substrates are attracted to the holding portions of the respective substrates. preferable.

In the separation step and the separation step in the above separation method, it is preferable to use a bundle of fluids ejected from the same ejection unit.

The above separation method is suitable, for example, for separating an object having a fragile layer inside as a separation layer.
The fragile layer is preferably, for example, a porous layer. Further, the object to be separated preferably has a layer composed of a semiconductor substrate, and the porous layer is preferably a layer formed by subjecting the semiconductor substrate to an anodizing treatment.

The fragile layer is preferably a layer having, for example, microbubbles. Further, the object to be separated preferably has a layer formed of a semiconductor substrate, and the layer having the microbubbles is preferably a layer formed by implanting ions into the semiconductor substrate.

In the above separation method, it is preferable to use, for example, water as the fluid.

The above separation method is suitable for manufacturing a semiconductor substrate.

In the method of manufacturing a semiconductor substrate according to the present invention, a step of forming a first substrate in which a porous layer and a non-porous layer are sequentially formed on one surface; and forming the first substrate and the second substrate. To form a bonded substrate by laminating the non-porous layer on the inside, and spraying the bundled fluid toward the vicinity of the porous layer of the bonded substrate to form a bonded substrate. The method includes a step of separating the substrates into a plurality of substrates, and a step of separating the substrates while injecting a fluid between the separated substrates.

In the method of manufacturing a semiconductor substrate described above, the step of forming the first substrate may include a step of forming a porous layer on one surface of the substrate by subjecting the substrate to anodizing treatment. preferable.

In the above method for manufacturing a semiconductor substrate, the step of forming the first substrate includes a step of forming a porous layer on one surface of the single-crystal silicon substrate by performing anodizing treatment on the substrate. And epitaxially growing a single-crystal silicon layer as a non-porous layer on the porous layer.

In the above method of manufacturing a semiconductor substrate, the step of forming the first substrate preferably further includes a step of forming an insulating layer on the epitaxially grown single-crystal silicon layer. The insulating layer is preferably made of, for example, silicon oxide.

In the method of manufacturing a semiconductor substrate described above, in the step of forming the insulating layer, it is preferable to form an insulating layer made of silicon oxide by oxidizing the surface of the epitaxially grown single crystal silicon layer.

In the above method of manufacturing a semiconductor substrate, it is preferable that the second substrate is made of, for example, a silicon substrate.

In the above method of manufacturing a semiconductor substrate, it is preferable that the second substrate is formed of, for example, a light-transmitting substrate.

In the above method of manufacturing a semiconductor substrate, it is preferable that the method further includes a step of removing the porous layer remaining on the second substrate after the step of separating the separated substrates.

In the above method of manufacturing a semiconductor substrate, it is preferable that the method further includes, after the step of removing the porous layer, a step of flattening the surface of the resultant product.

In the method of manufacturing a semiconductor substrate described above, it is preferable that the method further includes, after the step of separating the separated substrates, a step of removing the porous layer remaining on the first substrate side to make it reusable. .

Another method of manufacturing a semiconductor substrate according to the present invention comprises the steps of: implanting ions to a predetermined depth from the surface of a single crystal semiconductor substrate to form a first substrate having a microbubble layer formed thereon; Laminating a second substrate on the surface side of the first substrate to form a bonded substrate, and bonding the bundle while injecting a bundle of fluid toward the vicinity of the microbubble layer of the bonded substrate. The method includes a step of separating the bonded substrates into two substrates, and a step of separating the substrates while injecting a fluid between the separated substrates.

In the method for manufacturing another semiconductor substrate, the step of forming the first substrate includes a step of forming an insulating layer on a surface of the substrate before the step of implanting ions into the substrate. Is preferred. The insulating layer is preferably made of, for example, silicon oxide.

In the method of manufacturing another semiconductor substrate, it is preferable that, in the step of forming the insulating layer, an insulating layer made of silicon oxide is formed by oxidizing a surface of the substrate made of the single crystal semiconductor. .

In the above-mentioned other method of manufacturing a semiconductor substrate, it is preferable that the second substrate is made of, for example, a silicon substrate.

In the above other method for manufacturing a semiconductor substrate, it is preferable that the second substrate is formed of, for example, a light-transmitting substrate.

[0049] In the above another method of manufacturing a semiconductor substrate, it is preferable that the method further comprises, after the step of separating the separated substrates, a step of removing a microbubble layer remaining on the second substrate side.

It is preferable that the above method for manufacturing a semiconductor substrate further includes a step of flattening the surface of the resultant product after the step of removing the microbubble layer.

In the above another method of manufacturing a semiconductor substrate, after the step of separating the separated substrates, a step of removing a microbubble layer remaining on the first substrate side to make it reusable is further included. Is preferred.

In the above method for manufacturing a semiconductor substrate, it is preferable to use, for example, water as the fluid.

[0053]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a view for explaining a method of manufacturing an SOI substrate according to a preferred embodiment of the present invention in the order of steps.

In the step shown in FIG. 1A, a single-crystal Si substrate 11 is prepared, and a porous Si layer 12 is formed on the surface thereof by anodization or the like. Next, in a step shown in FIG. 1B, a single-crystal S which is a non-porous layer is formed on the porous Si layer 12.
The i-layer 13 is formed by an epitaxial growth method, and then the surface of the single-crystal Si
An iO ₂ layer 15 is formed. Thereby, a first substrate () is formed.

In the step shown in FIG. 1C, a single crystal Si substrate 14 is prepared as the second substrate (), and the SiO ₂ layer 15 of the first substrate () and the second substrate () are Then, the first substrate () and the second substrate () are brought into close contact with each other at room temperature. After that, the first substrate () and the second substrate () are bonded to each other by anodic bonding, pressing, heat treatment, or a combination thereof. With this process,
The second substrate () and the SiO 2 layer 15 are firmly bonded. The SiO ₂ layer 15 is made of single crystal Si as described above.
It may be formed on the substrate 11 side, may be formed on the second substrate (), may be formed on both, and as a result,
When the first substrate and the second substrate are brought into close contact with each other, FIG.
The state shown in FIG.

In the step shown in FIG. 1D, the two bonded substrates are separated at the porous Si layer 12. Thereby, the second substrate side ("+") has a laminated structure of the porous Si layer 12 "/ the single-crystal Si layer 13 / the insulating layer 15 / the single-crystal Si substrate 14. On the other hand, on the first substrate side (')
Has a structure having a porous Si layer 12 ′ on a single-crystal Si substrate 11.

The substrate (') after the separation is formed by removing the remaining porous Si layer 12' and, if necessary, flattening the surface to form the first substrate () again. Used as a single crystal Si substrate 11.

After separating the bonded substrates, FIG.
In the step shown in (e), the porous layer 12 '' on the surface of the second substrate side ("+") is selectively removed. This allows
A substrate having a stacked structure of single crystal Si layer 13 / insulating layer 15 / single crystal Si substrate 14, that is, a substrate having an SOI structure is obtained.

In this embodiment, the process shown in FIG. 1D, that is, two bonded substrates (hereinafter referred to as
In the step of separating the bonded substrate, a high-pressure liquid or gas (fluid) is selectively jetted to the porous Si layer, which is a separation region, to separate the substrate in the separation region.
Use a separation device that separates the sheets.

[Basic Configuration of Separation Apparatus]
The water jet method was applied. In general,
In the water jet method, water is jetted onto a target in a high-speed, high-pressure bundle flow to cut, process, remove coating films on the surface of ceramics, metal, concrete, resin, rubber, wood, etc. This is a method of cleaning the surface (see Water Jet Vol. 1, No. 1, page 4).

This separation apparatus jets a high-speed, high-pressure fluid in a bundle-like flow in the direction of the surface of the substrate to the porous layer (separation region) of the bonded substrate, which is a fragile structure. The substrate is separated at the portion of the porous layer by selectively collapsing the porous layer. Hereinafter, this bundled flow is referred to as a “jet”. Further, the fluid constituting the jet is referred to as “jet constituting medium”. As a jet constituting medium, water, an organic solvent such as alcohol, hydrofluoric acid,
Nitric acid and other acids, potassium hydroxide and other alkalis, air, nitrogen gas, carbon dioxide gas, rare gas, etching gas and other gases, plasma and the like can be used.

This separation device removes the porous layer from the outer peripheral portion toward the central portion by jetting a jet toward the porous layer (separation region) exposed on the side surface of the bonded substrate. As a result, the bonded substrate is separated into two substrates without damaging the main body portion, removing only the separation region having weak mechanical strength. Note that even when the side surface of the bonded substrate is covered with some thin layer and the porous layer is not exposed, the layer is removed by jetting, and thereafter, the bonding is performed in the same manner as described above. The mating substrate can be separated.

At the periphery of the bonded substrate, the effect of separating the bonded substrate into two substrates as described above is as follows.
This is extremely effective when there is a V-shaped (concave) groove along the circumferential direction in the outer peripheral portion of the bonded substrate. FIG. 2 is a diagram conceptually showing a force acting on a bonded substrate depending on the presence or absence of a V-shaped groove. FIG. 2A shows a bonded substrate having a V-shaped groove 22, and FIG. 2B shows a bonded substrate having no V-shaped groove.

As shown in FIG. 2A, in a bonded substrate having a V-shaped groove 22, as shown by an arrow 23,
A force (hereinafter, separation force) is applied from the inside to the outside of the bonded substrate. On the other hand, as shown in FIG. 2B, in the bonded substrate having a convex outer peripheral portion, the arrow 24
As shown in (2), a force is applied from the outside to the inside of the bonded substrate. Therefore, in the bonded substrate whose outer peripheral portion has a convex shape, the separating force does not act unless the outer peripheral portion of the porous layer 12 which is the separation region is removed by the jet 21.

Even if a thin layer is formed on the surface of the outer peripheral portion of the bonded substrate, as shown in FIG. Since a separating force acts on the substrate, the layer can be easily broken.

For effective use of the jet, it is preferable that the width W1 of the opening of the V-shaped groove 22 is equal to or greater than the diameter d of the jet 21. For example,
Consider a case where the first substrate () and the second substrate () are each about 1 mm thick and the bonded substrate is about 2 mm thick.
Since the width W1 of the opening of the V-shaped groove 22 is usually about 1 mm, the diameter of the jet is preferably 1 mm or less. A typical water jet device has a diameter of 0.1
Since a jet of about 0.5 mm is used, such a general water jet device (for example, a water jet nozzle) can be used.

Here, as the shape of the nozzle for jetting the jet, various shapes other than a circular shape can be adopted. For example, by adopting a slit-shaped nozzle and jetting a jet having an elongated rectangular cross section, the jet can be efficiently inserted (inserted between two substrates) into the separation region.

The jet injection conditions may be determined according to, for example, the type of the separation region (for example, the porous layer), the shape of the outer peripheral portion of the bonded substrate, and the like. The jet ejection conditions include, for example, the pressure applied to the jet constituting medium, the scanning speed of the jet, the width or diameter of the nozzle (substantially the same as the diameter of the jet), the nozzle shape, the distance between the nozzle and the separation region, the flow rate of the jet constituting medium. Are important parameters.

For the method of separating the bonded substrates, for example,
1) A method in which a jet is inserted parallel to the bonding surface in the vicinity of the bonding surface and the nozzle is scanned along the bonding surface, and 2) The nozzle is parallel to the bonding surface in the vicinity of the bonding surface. 3) a method in which a jet is inserted and a bonded substrate is scanned, and 3) a method in which a jet is inserted in parallel with the bonding surface with respect to the vicinity of the bonding surface and the jet is scanned in a fan shape with the nozzle vicinity as a hip. 4)
A method in which a jet is inserted in the vicinity of the bonding surface in parallel with the bonding surface and the bonded substrate is rotated about the center of the bonded substrate as an axis (particularly effective when the bonded substrate has a disk shape). ). Note that the jet does not necessarily need to be jetted completely parallel to the bonding surface.

The axial separating force applied to the bonded substrate is preferably, for example, about several hundred gf per 1 cm 2 in order to prevent the substrate from being damaged.

FIG. 3 is a diagram showing a schematic configuration of a separation apparatus according to a preferred embodiment of the present invention. This separation device 10
In the case of 0, after the bonded substrate is separated into two substrates by a jet, the two substrates are separated while the jet is sandwiched between the two substrates. As a result, the two separated substrates can be easily separated from each other, and each substrate is prevented from being damaged.

The separation apparatus 100 is provided with a vacuum suction mechanism 10
Substrates 8a and 109a are provided. The substrate holders 108 and 109 hold the bonded substrate 101 from both sides. The bonded substrate 101 has a porous layer 1 which is a fragile component inside.
The porous layer 101b is separated into two substrates 101a and 101c by the separation device 100. In the separation apparatus 100, for example, the substrate 101a is set so as to be on the first substrate side (') in FIG. 1 and the substrate 101c is set on the second substrate side ("+") in FIG.

The substrate holders 108 and 109 exist on the same rotation axis. The substrate holding unit 108 is provided with the bearing 10
4 is connected to one end of a rotating shaft 106 rotatably supported by the support base 102, and the other end of the rotating shaft 104 is
Driving source (for example, motor) 11 fixed to support portion 110
0 rotation shaft. Therefore, the driving source 11
Due to the rotational force that generates 0, the bonded substrate 101 that is vacuum-adsorbed to the substrate holding unit 108 rotates.
The drive source 110 rotates the rotating shaft 106 at a specified rotation speed in accordance with a command from a controller (not shown) when the bonded substrate 101 is separated.

The substrate holding unit 109 is connected to one end of a rotating shaft 107 slidably and rotatably supported by the supporting unit 103 via a bearing 105. The other end of the rotating shaft 107 is connected to a driving source ( (For example, a motor) 111. Here, it is needless to say that the speed at which the drive source 110 rotates the rotary shaft 106 and the speed at which the drive source 111 rotates the rotary shaft 107 need to be synchronized.
This is to prevent the bonded substrate 101 from being twisted.

It should be noted that it is not always necessary to provide both the driving sources 110 and 111, and it is possible to adopt a configuration having either one. For example, when only the driving source 110 is provided, before the bonded substrate 101 is separated, the rotating shaft 106, the substrate holding unit 108, the bonded substrate 1
01, the substrate holder 109 and the rotating shaft 107 rotate integrally. After the bonded substrate 101 is separated into two substrates, each part on the rotating shaft 107 side comes to rest.

Further, the rotational force generated by one drive source is 2
The rotating shafts 106 and 107 can be rotated by the branched rotational forces.

A spring 113 for pressing the bonded substrate 101 is attached to the support 103 that supports the rotating shaft 107. Therefore, the bonded substrate 101
Is not absorbed by the vacuum suction mechanisms 108a and 109a,
The separated substrates do not fall. In addition, by separating the bonded substrate 101 while pressing it, the bonded substrate 101 can be stably held.

A spring for pressing the bonded substrate 101 may be similarly provided on the rotating shaft 106 side.

The separation device 100 is provided with the substrate holding unit 10
An adjustment mechanism for adjusting the interval between 8,109 is provided. Hereinafter, a configuration example of the adjustment mechanism will be described.

FIG. 5 is a diagram showing a first configuration example of the adjusting mechanism. The configuration example shown in FIG. 5 is an adjustment mechanism using an air cylinder 122. The air cylinder 122 is fixed to, for example, the support portion 103 and its piston rod 1
The drive source 111 is moved by 21. Laminated substrate 1
01 to the separation device 100, the substrate holding unit 1
The air cylinder 122 is controlled so that the drive source 111 is moved in a direction to widen the interval between 08 and 109 (positive direction of the x-axis). In this state, the bonded substrate 101 is disposed between the substrate holding portions 108 and 109, and the driving of the piston rod 121 by the air cylinder 122 is released, so that the substrate holding portion 109 holds the bonded substrate 101 by the action of the spring 113. Will be pressed.

FIG. 6 is a diagram showing a second configuration example of the adjusting mechanism. The configuration example shown in FIG. 6 is an adjustment mechanism using an eccentric cam 131 and a motor. The eccentric cam 131 is connected to a motor (not shown), and adjusts an interval between the substrate holding units 108 and 109 by sliding a driving plate 132 connected to a rear end of the motor 111. As described above, a force in the negative direction of the x-axis is acting on the rotating shaft 107 by the spring 113, and when holding the bonded substrate 101,
A gap is formed between the eccentric cam 131 and the driving plate 132. Therefore, when holding the bonded substrate 101, a pressing force acts on the bonded substrate 101.

Note that the substrate holders 108, 1 as described above
A mechanism for adjusting the interval between the pixels 09 may be provided also on the substrate holding unit 108 side.

Next, a description will be given of the substrate separation processing by the separation apparatus 100.

The bonded substrate 101 is attached to the separation device 100.
Is set, first, the bonded substrate 101 is transferred between the substrate holding units 108 and 109 by a transfer robot, for example, and the center of the bonded substrate 101 is set to the substrate holding units 108 and 109.
It is held in a state where it is aligned with the center of 109. Then, the bonded substrate 101 is vacuum-sucked to the substrate holding unit 108.

Next, the substrate holder 109 is pressed against the bonded substrate 101 by the force of the spring 113. Specifically, for example, when the adjustment mechanism shown in FIG. 5 is employed as an adjustment mechanism for the interval between the substrate holding units 108 and 109, the driving of the piston rod 121 by the air cylinder 122 may be released. For example, when the adjusting mechanism shown in FIG. 6 is employed as the adjusting mechanism, the eccentric cam 131 is applied so that the spring 113 applies a pressing force to the bonded substrate 101.
Can be rotated.

Here, when performing the separation process, the bonded substrate 101 may or may not be suctioned by the vacuum suction mechanisms 108a and 109a. This is because the bonded substrate 101 is held by the pressing force of the spring 113. However, when the pressing force is weakened, it is preferable that the bonded base substrate 101 is vacuum-adsorbed.

Next, the rotating shafts 106 and 107 are rotated synchronously by the driving sources 110 and 111. In this state, a high-pressure jet forming medium (for example, water) is sent to the injection nozzle 112 from a high-pressure pump (not shown), and a high-speed, high-pressure jet is injected from the injection nozzle 112. The jet jet is inserted near the separation region of the bonded substrate 101. When the jet is sandwiched, the porous layer 101b, which is a fragile structure, is broken in the bonded substrate 101, and the bonded substrate 101 is separated into two substrates by the porous layer 101b.

Next, the two physically separated substrates 101a and 101b are separated from each other while the jet is sandwiched in the separation region (porous layer 101b) of the bonded substrate 101. Specifically, for example, the substrate holding units 108 and 109
When the adjusting mechanism shown in FIG. 5 is adopted as the adjusting mechanism for the interval between the substrates, the air cylinder 122 moves the piston rod 121 in the positive x-axis direction (spring (The direction in which the pin 113 is contracted). Also, for example, when the adjustment mechanism shown in FIG. 6 is employed as the adjustment mechanism, the eccentric cam 131 is rotated while the respective substrates are vacuum-sucked on the substrate holding units 108 and 109, so that the rotation shaft 107 is rotated by x. It may be driven in the positive direction of the shaft (the direction in which the spring 113 contracts).

As shown in FIG. 4, the substrates 101a and 101c
When the separation of the substrates is completed, the jetting of the jet is stopped, and the substrates are held by the substrate holding units 108 and 1 by, for example, a transfer robot.
09 can be removed.

The injection nozzle 112 may be fixed, but is preferably movable. For example, depending on the type and size of the bonded substrate 101, the injection nozzle 11
This is because it is preferable to adjust the position of No. 2.

FIG. 7 is a diagram conceptually showing an example of a driving robot for driving the injection nozzle 112. As shown in FIG. The driving robot 160 shown in FIG. 7 moves the injection nozzle 112 along the path 170. The bonded base substrate 101 is attached to the substrate holding unit 108,
The drive robot 160 moves the ejection nozzle 112 to the retreat position 171 when holding it at 109 and removing it. On the other hand, when separating and separating the bonded substrate 101, the driving robot 160 moves the injection nozzle 112 to the working position 172. Thus, the bonded substrate 1
By retracting the injection nozzle 112 when attaching / detaching the 01, the work of attaching / detaching the bonded substrate 101, particularly the work of attaching / detaching the bonded substrate 101 by a transfer robot, can be made more efficient.

Here, when separating and separating the bonded substrate 101, it is also effective to scan the jet nozzle 112 in the plane direction of the bonded substrate 101 on the separation region of the bonded substrate 101. In this case, the bonded substrate 101
A good separation process can be performed without rotating.

FIG. 8 is a view conceptually showing another example of a driving robot for driving the injection nozzle 112. The driving robot 161 shown in FIG. 8 moves the injection nozzle 112 along the path 180. The base substrate 101 is attached to the substrate holding unit 10.
The drive robot 161 moves the ejection nozzle 112 to the retreat position 181 when holding it at 8, 109 and removing it. On the other hand, when separating and separating the bonded substrate 101, the driving robot 161 moves the injection nozzle 112 to the working position 182. In this way, by retreating the injection nozzle 112 when attaching and detaching the bonded substrate 101, the operation of attaching and detaching the bonded substrate 101, particularly the operation of attaching and detaching the bonded substrate 101 by a transfer robot, can be made more efficient. .

Here, when separating and separating the bonded substrate 101, it is also effective to scan the jet nozzle 112 in the surface direction of the bonded substrate 101 on the separation region of the bonded substrate 101. In this case, the bonded substrate 101
A good separation process can be performed without rotating.

As described above, the method of separating the two physically separated substrates 101a and 101c in a state where the jet is sandwiched in the separation region of the bonded substrate 101, thereby adopting the method of forming the jet forming medium. The influence of surface tension is reduced, and the two substrates 101a and 101c can be easily separated. Hereinafter, this principle will be described.

FIG. 9 is a diagram for explaining the surface tension acting between two substrates. Two substrates 101a and 1
When the jet constituting medium (for example, water) 150 is sandwiched between 01c, the surface tension of the jet constituting medium 150 acts on the two substrates 101a and 101c. Therefore,
A considerable force is required to pull and separate the substrates 101a and 101c in the axial direction (x-axis direction).
There is a risk that 1c will break. In order to avoid this, it is conceivable to separate the two substrates 101a and 101c by sliding them in the plane direction (yz plane). In this case, however, there is a risk that the separation surface may be damaged.

The problem of such surface tension can be solved by injecting a fluid between two substrates to apply a force in a direction to separate the two substrates. That is, when the two substrates 101a and 10c are separated from each other, a force (pressure) is applied in a direction in which the two substrates are separated by inserting a fluid (for example, water) between the substrates. FIG. 10 is a diagram schematically illustrating a principle of applying a force in a direction of separating two substrates by a fluid.

The fluid to be interposed between the substrates to separate the substrates may be supplied from a dedicated ejection port, but it is reasonable to supply the fluid from the ejection nozzle 112. That is,
By sandwiching a jet from the injection nozzle 112 into the bonded substrate 101, the bonded substrate 101 is physically
After separation into two substrates, the two substrates can be easily separated with a simple configuration by inserting a jet between the substrates from the injection nozzle 112 when separating the two substrates. Here, it is also effective to appropriately switch the pressure of the jet constituting medium between when the bonded substrate 101 is physically separated and when the two separated substrates are separated from each other.

The above separating apparatus 100 is for processing a single bonded substrate. A plurality of bonded substrates are arranged side by side in the plane direction, and the jet nozzle of the separation apparatus is scanned in the plane direction. Thus, the separation processing can be performed on a plurality of bonded substrates at once.

Further, while holding a plurality of bonded substrates arranged in the axial direction, a mechanism for scanning the injection nozzle of the separation device in the axial direction is provided, and the separation processing is sequentially performed on the plurality of bonded substrates. You can also.

As described above, the bonded substrate is physically
After separating into two substrates, the two substrates are separated while injecting a fluid between the two substrates, whereby the separated substrates can be easily separated from each other. Can be prevented from being damaged. Therefore, a high-quality substrate can be manufactured with a high yield.

This separating apparatus can be used for separating not only a bonded substrate and other semiconductor substrates but also various members. The separating device is suitable for separating a plate-shaped member, but also has an effect of easily separating the separated members when separating a non-plate-shaped member.

Hereinafter, an embodiment to which the separation device 100 is applied will be described. The separation apparatus 100 is particularly suitable for separating a substrate having a fragile layer as a separation layer. As the separation layer, for example, a porous layer, a microbubble layer (microcavity layer) formed by ion implantation, or the like is preferable.

(Example 1) Specific resistance 0.01 to 0.02
A (Ω · cm) P-type or N-type first single-crystal Si substrate was anodized in an HF solution to form a porous Si layer (corresponding to the step shown in FIG. 1A). The anodizing conditions are as follows.

Current density: 7 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 11 (min) Thickness of porous Si: 12 (μm) The porous Si layer is used to form a high quality epitaxial Si layer thereon, and also serves as a separation layer. The thickness of the porous Si layer is not limited to the above-mentioned thickness, but is preferably about several hundred μm to 0.1 μm.

This substrate was placed in an oxygen atmosphere at 400 ° C.
For 1 hour. Due to this oxidation, the inner wall of the hole of the porous Si layer was covered with the thermal oxide film. The surface of the porous Si layer is treated with hydrofluoric acid to remove only the oxide film on the surface of the porous Si layer while leaving the oxide film on the inner walls of the pores.
CVD (Chemical Vapor Dep.)
Single-crystal Si was epitaxially grown to a thickness of 0.3 μm by the position method. The growth conditions are as follows.

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: 0.3 (μm / min) Further, as an insulating layer, an oxide film (SiO ₂ layer) of 200 nm was formed on the surface of this epitaxial Si layer by thermal oxidation (corresponding to the step shown in FIG. 1B).

Next, the SiO ₂ layer of the first substrate was
The two substrates were separately stacked so that the surface of the separately prepared second Si substrate faced, and then closely adhered. Then, a heat treatment was performed at a temperature of 1180 ° C. for 5 minutes to bond the two substrates together (FIG. 1C).
).

Next, the bonded substrate 101 formed as described above was separated by the separating device 100 (FIG. 1).
(Corresponds to the step shown in (d)). The details are as follows.

The bonded substrate 101 is attached to the substrate holding section 108,
It was vertically supported between the substrates 109 and pressed and held by the substrate holding unit 109. Then, the jet nozzle 1 having a diameter of 0.15 mm is directed toward the beveled concave portion of the bonded substrate 101.
Pure water having a pressure of 12 to 2000 kgf / cm ² was sprayed in parallel to the bonding interface of the bonded substrate 101. At that time, the driving nozzle 161 shown in FIG.
12, the separation process was performed while reciprocally scanning along the bonding interface of the bonded substrate 101. At this time, the separation process was performed without rotating the bonded substrate 101.

When the physical separation of the bonded substrate 101 is completed, the two separated substrates are in close contact with each other via pure water.

Next, the jet pressure was set to 500 kgf /
After the pressure is reduced to ² cm ² , the injection nozzle 112 is moved to a position immediately above the center of the two substrates (at a position 182 in FIG. 8), and the respective substrates are vacuum-adsorbed to the substrate holders 108 and 109, respectively. Then, the substrate holding unit 109 was moved backward (moved in the positive direction of the x-axis) to separate the two substrates.

As a result of the above processing, in addition to the SiO ₂ layer and the epitaxial Si layer formed on the surface of the first substrate, a part of the porous Si layer was transferred to the second substrate.
Then, the porous Si layer remained on the surface of the first substrate.

Next, the porous S transferred on the second substrate
The i-layer was selectively etched while being stirred with a mixed solution of water, 49% hydrofluoric acid and 30% hydrogen peroxide (corresponding to the step shown in FIG. 1E). At this time, the single-crystal Si of the second substrate served as an etch stop, and the porous Si was selectively etched and completely removed.

Non-porous Si by the above etching solution
The etching rate of the single crystal is extremely low, the selectivity with the etching rate of the porous layer is 10 ⁵ or more, and the etching amount of the non-porous layer (several tens of angstroms) is a practically acceptable amount.

Through the above steps, 0.2 μm is formed on the Si oxide film.
An SOI substrate having a single-crystal Si layer having a thickness of μm was formed. When the film thickness of the single-crystal Si layer after selectively etching the porous Si layer was measured at 100 points over the entire area in the plane, the film thickness was 201 nm.
± 4 nm.

As a result of observation of a cross section with a transmission electron microscope, it was confirmed that no new crystal defects were introduced into the single crystal Si layer, and good crystallinity was maintained.

Further, after the above product was subjected to a heat treatment in hydrogen at 1100 ° C. for 1 hour, the surface roughness was evaluated by an atomic force microscope. The average square roughness in a 50 μm square region was obtained. Was about 0.2 nm. This is equivalent to a commercially available Si wafer.

Similar results were obtained when the oxide film (SiO ₂ film) was formed not on the surface of the epitaxial layer but on the surface of the second substrate or on both.

On the other hand, the porous Si layer remaining on the first substrate side was selectively etched while being stirred with a mixed solution of water, 40% hydrofluoric acid and 30% hydrogen peroxide. Thereafter, the resulting product was subjected to surface treatment such as hydrogen annealing or surface polishing, so that it could be reused as the first substrate or the second substrate.

The above-described separation apparatus is an example in which the jet nozzle 112 is scanned. However, the separation apparatus may scan the bonded substrate side, or may scan both sides. Alternatively, the separation process may be performed while rotating the bonded substrate without scanning either the ejection nozzle 112 or the bonded substrate.

(Example 2) Specific resistance 0.01 to 0.02
A two-stage anodization was performed on a (Ω · cm) P-type or N-type first single-crystal Si substrate in an HF solution to form two porous layers (see FIG. 1A). Corresponding to the steps shown). The anodizing conditions are as follows.

<First Anodization> Current Density: 7 (mA / cm ² ) Anodizing Solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 5 (min) First Thickness of porous Si: 6 (μm) <Second-stage anodization> Current density: 30 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 10 (seconds) Thickness of the second porous Si: 0.3 (μm) By forming the porous Si layer into a two-layer structure, the porous Si layer previously anodized at a low current on the substrate surface side is formed. Was used to form a high-quality epitaxial Si layer, and the lower porous Si layer anodized with a high current later was used as a separation layer to separate the functions. The thickness of the porous Si layer formed at a low current is not limited to the above thickness (6 μm), but is preferably about several hundred μm to 0.1 μm. Further, the thickness of the porous Si layer formed at a high current is not limited to the above-mentioned thickness (0.3 μm), but may be any thickness as long as the bonded substrate can be separated by a jet.

Here, a third layer or more layers may be formed after the formation of the second porous Si layer.

This substrate was placed in an oxygen atmosphere at 400 ° C.
For 1 hour. Due to this oxidation, the inner wall of the hole of the porous Si layer was covered with the thermal oxide film. The surface of the porous Si layer is treated with hydrofluoric acid to remove only the oxide film on the surface of the porous Si layer while leaving the oxide film on the inner wall of the hole.
CVD (Chemical Vapor Dep.)
Single crystal Si was epitaxially grown by 0.3 μm by the position method. The growth conditions are as follows.

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: 0.3 (μm / min) Further, as an insulating layer, an oxide film (SiO ₂ layer) of 200 nm was formed on the surface of this epitaxial Si layer by thermal oxidation (corresponding to the step shown in FIG. 1B).

Next, the two substrates were superimposed on and brought into close contact with the SiO ₂ layer so that the surface of the separately prepared second substrate faced, and then heat-treated at a temperature of 1180 ° C. for 5 minutes. (Corresponding to the step shown in FIG. 1C).

Next, the bonded substrate 101 formed as described above was separated by the separating device 100 (FIG. 1).
(Corresponds to the step shown in (d)). The details are as follows.

The bonded substrate 101 is moved to the substrate holding section 108,
It was vertically supported between the substrates 109 and pressed and held by the substrate holding unit 109. Then, the bonded substrate 101 is set at 8 rp.
m at a speed of m.

Next, after jetting high-pressure pure water from the jet nozzle 112, the jet nozzle 112 was moved along the path 180 by the driving robot 161 shown in FIG. Then, at the working position 182, pure water at a pressure of 400 kgf / cm ² was sprayed in a vertical direction from the spray nozzle 112 having a diameter of 0.20 mm toward the beveling recess of the bonded substrate 101 for 2 minutes.

By this processing, the bonded substrate 101 is physically separated into two substrates. At this point, the separated two substrates are in close contact with each other via pure water.

Next, the jet pressure was set to 500 kgf /
After raising the pressure to cm ² , while keeping the position of the injection nozzle 112, the substrate holding unit 109 was moved backward in the support unit 406 (moved in the positive direction of the x-axis) to separate the two substrates. Note that when the substrate holding unit 109 is retracted, that is, when the two substrates are separated from each other,
Similar results were obtained without rotation.

As a result of the above processing, in addition to the SiO ₂ layer and the epitaxial Si layer formed on the surface of the first substrate, a part of the porous Si layer was transferred to the second substrate.
Then, the porous Si layer remained on the surface of the first substrate.

Thereafter, the same processing as in the first embodiment was executed, and the same result was obtained.

(Example 3) Specific resistance 0.01 to 0.02
A (Ω · cm) P-type or N-type first single-crystal Si substrate was anodized in an HF solution to form a porous Si layer. The anodizing conditions are as follows.

Current density: 7 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1: 1 Time: 11 (min) Thickness of porous Si: 12 (μm) In addition, the thickness of the porous Si layer is the above thickness (12 μm).
However, the thickness is preferably about several hundred μm to about 0.1 μm.

This substrate was placed in an oxygen atmosphere at 400 ° C.
For 1 hour. Due to this oxidation, the inner wall of the hole of the porous Si layer was covered with the thermal oxide film. The surface of the porous Si layer is treated with hydrofluoric acid to remove only the oxide film on the surface of the porous Si layer while leaving the oxide film on the inner walls of the pores.
CVD (Chemical Vapor Depo)
Single-crystal Si was epitaxially grown to a thickness of 0.3 μm by the STI method. The growth conditions are as follows.

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: 0.3 (μm / min) Further, as an insulating layer, an oxide film (SiO ₂ layer) of 200 nm was formed on the surface of the epitaxial Si layer by thermal oxidation.

Next, ions are implanted from the surface of the first substrate so that the projection range is at the interface of the epitaxial layer / porous Si layer, the interface of the porous Si layer / substrate, or in the porous Si layer. Was. As a result, the layer acting as the separation layer is positioned at the depth of the projection range,
(crocavity layer) or a strained layer formed by a layer containing a high concentration of implanted ion species.

Then, both substrates were brought into close contact with the surface of the SiO ₂ layer of the first substrate so that the separately prepared second Si substrate faced, and then heat-treated at a temperature of 600 ° C. for 10 hours. Then, both substrates were bonded together. Here, by pre-treating both substrates with N ₂ plasma or the like before bringing both substrates into close contact with each other, the bonding strength was increased.

Next, the bonded substrate 101 formed as described above was separated by the separating device 100. The details are as follows.

The bonded substrate 101 is connected to the substrate holder 108,
It was vertically supported between the substrates 109 and pressed and held by the substrate holding unit 109. Then, the jet nozzle 1 having a diameter of 0.15 mm is directed toward the beveled concave portion of the bonded substrate 101.
Pure water having a pressure of 12 to 2000 kgf / cm ² was sprayed in parallel to the bonding interface of the bonded substrate 101. At that time, the driving nozzle 161 shown in FIG.
12, the separation process was performed while reciprocally scanning along the bonding interface of the bonded substrate 101. At this time, the separation process was performed without rotating the bonded substrate 101.

When the physical separation of the bonded substrate 101 is completed, the two separated substrates are in close contact with each other via pure water.

Next, the jet pressure was set to 500 kgf /
After the pressure is reduced to ² cm ² , the injection nozzle 112 is moved to a position immediately above the center of the two substrates (at a position 182 in FIG. 8), and the respective substrates are vacuum-adsorbed to the substrate holders 108 and 109, respectively. Then, the substrate holding unit 109 was moved backward (moved in the positive direction of the x-axis) to separate the two substrates.

As a result of the above processing, in addition to the SiO ₂ layer and the epitaxial Si layer formed on the surface of the first substrate, a part of the porous Si layer (separation layer) is transferred to the second substrate. Was done. Then, the porous Si layer remained on the surface of the first substrate.

Next, the porous S transferred on the second substrate
The i-layer (separation layer) was selectively etched while being stirred with a mixed solution of water, 49% hydrofluoric acid and 30% hydrogen peroxide. At this time, the single-crystal Si of the second substrate served as an etch stop, and the porous Si was selectively etched and completely removed.

According to the above steps, 0.2 μm is formed on the Si oxide film.
An SOI substrate having a single-crystal Si layer having a thickness of μm was formed. When the film thickness of the single-crystal Si layer after selectively etching the porous Si layer was measured at 100 points over the entire area in the plane, the film thickness was 201 nm.
± 4 nm.

As a result of observation of a cross section with a transmission electron microscope, it was confirmed that no new crystal defects were introduced into the single-crystal Si layer, and good crystallinity was maintained.

Further, after the above product was subjected to a heat treatment in hydrogen at 1100 ° C. for 1 hour, the surface roughness was evaluated by an atomic force microscope, and the mean square roughness in a 50 μm square region was obtained. Was about 0.2 nm. This is equivalent to a commercially available Si wafer.

Similar results were obtained when the oxide film (SiO ₂ film) was formed not on the surface of the epitaxial layer but on the surface of the second substrate, and when both were formed.

On the other hand, the porous Si layer remaining on the first substrate side was selectively etched while being stirred with a mixed solution of water, 40% hydrofluoric acid and 30% hydrogen peroxide. Thereafter, the resulting product was subjected to surface treatment such as hydrogen annealing or surface polishing, so that it could be reused as the first substrate or the second substrate.

The removal of the separation layer may be performed not by etching but by polishing. In this case, an SOI substrate of the same quality was obtained. In this case, it is not necessary to perform heat treatment in hydrogen.

Also, a quartz or other light-transmitting substrate can be adopted as the second substrate. In this case, a good substrate as described above could be obtained.

Example 4 On a surface of a first single crystal Si substrate, an oxide film (S
iO ₂ layer). Here, before thermal oxidation, the surface of the first single-crystal Si substrate is subjected to CVD (Chemical Va).
Single-crystal Si having a thickness of about 0.5 μm may be epitaxially grown by a por deposition method.
The growth conditions in this case are as follows, for example.

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: 0.3 (μm / min) Ion implantation was performed from the surface of the first substrate such that the projection range was in the Si substrate or in the epitaxial layer. As a result, a layer serving as a separation layer was formed as a microbubble layer or a strained layer formed of a high-concentration layer of implanted ion species at the depth of the projection range.

Next, the two substrates were brought into close contact with the surface of the SiO ₂ layer of the first substrate so that the separately prepared second Si substrate faced, and then heat-treated at a temperature of 400 ° C. for 24 hours. Then, both substrates were bonded together. Here, the bonding strength was increased by pre-treating both substrates with N ₂ plasma or the like before bringing both substrates into close contact.

Next, the bonded substrate 101 formed as described above was separated by the separating device 100. The details are as follows.

The bonded substrate 101 is connected to the substrate holding portion 108,
It was vertically supported between the substrates 109 and pressed and held by the substrate holding unit 109. Then, the bonded substrate 101 is set at 8 rp.
m at a speed of m.

Next, after jetting high-pressure pure water from the jet nozzle 112, the jet nozzle 112 was moved along the path 180 by the driving robot 161 shown in FIG. Then, at the working position 182, pure water at a pressure of 400 kgf / cm ² was sprayed in a vertical direction from the spray nozzle 112 having a diameter of 0.20 mm toward the beveling recess of the bonded substrate 101 for 2 minutes.

By this processing, the bonded substrate 101 is physically separated into two substrates. At this point, the separated two substrates are in close contact with each other via pure water.

Next, the jet pressure was set to 500 kgf /
After raising the pressure to cm ² , while keeping the position of the injection nozzle 112, the substrate holding unit 109 was moved backward in the support unit 406 (moved in the positive direction of the x-axis) to separate the two substrates. Note that when the substrate holding unit 109 is retracted, that is, when the two substrates are separated from each other,
Similar results were obtained without rotation.

As a result of the above processing, a part of the separation layer, in addition to the SiO ₂ layer and the epitaxial Si layer formed on the surface of the first substrate, was transferred to the second substrate. Then, the separation layer remained on the surface of the first substrate.

Next, the separation layer transferred onto the second substrate was selectively etched while being stirred with a mixed solution of water, 49% hydrofluoric acid and 30% hydrogen peroxide. At this time, the single-crystal Si of the second substrate served as an etch stop, and the porous Si was selectively etched and completely removed.

Through the above steps, an SOI substrate having a single-crystal Si layer on a Si oxide film could be formed. When the film thickness of the single crystal Si layer after selectively etching the porous Si layer was measured at 100 points over the entire area in the plane, the film thickness was 201 nm ± 4 nm.

As a result of observation of a cross section by a transmission electron microscope, it was confirmed that no new crystal defects were introduced into the single-crystal Si layer, and good crystallinity was maintained.

Further, after the above product was subjected to a heat treatment in hydrogen at 1100 ° C. for 1 hour, the surface roughness was evaluated by an atomic force microscope. As a result, the mean square roughness in a 50 μm square region was obtained. Was about 0.2 nm. This is equivalent to a commercially available Si wafer.

On the other hand, the separation layer remaining on the first substrate side was selectively etched while being stirred with a mixed solution of water, 40% hydrofluoric acid and 30% hydrogen peroxide. Thereafter, the resulting product was subjected to surface treatment such as hydrogen annealing or surface polishing, so that it could be reused as the first substrate or the second substrate.

The removal of the separation layer may be performed not by etching but by polishing. In this case, an SOI substrate of similar quality was obtained. In this case, it is not necessary to perform heat treatment in hydrogen.

In this embodiment, the surface region of a single-crystal Si substrate (first substrate) is separated by a second layer through a separation layer by ion implantation.
The separation layer is formed by ion implantation below the epitaxial layer using an epitaxial wafer, and the substrate is separated by the separation layer to transfer the epitaxial layer to the second substrate. You may.

In the above embodiment, after forming the separation layer by ion implantation, the SiO ₂ layer on the surface of the first substrate is removed to form an epitaxial layer and a SiO ₂ layer.
The first substrate is bonded to a second substrate, and the substrate is separated by a separation layer, whereby the epitaxial layer and SiO ₂ are separated.
The layer may be transferred to a second substrate. Example 5 A two-stage anodization was performed on a P-type or N-type first single-crystal Si substrate having a specific resistance of 0.01 to 0.02 Ω · cm in an HF solution to form a two-layer porous film. A layer was formed. The anodizing conditions are as follows.

<First Anodization> Current Density: 7 (mA / cm ² ) Anodizing Solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 11 (min) First Thickness of porous Si: 12 (μm) <Second-stage anodization> Current density: 17 (mA / cm ² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 3 (minutes) Thickness of the second porous Si: 3 (μm) By forming the porous Si layer into two layers, the porous Si of the surface layer previously anodized with a low current is made of high quality epitaxial. The respective functions were separated by using a lower porous Si layer used for forming a Si layer and subsequently anodized with a high current as a separation layer. The thickness of the porous Si layer formed at a low current is not limited to the above-mentioned thickness (12 μm), but may be several hundred μm.
The thickness is preferably about 0.1 μm. Further, the porous Si layer formed at a high current is not limited to the above thickness (3 μm).
What is necessary is just to ensure the thickness which can separate a bonding substrate by a jet.

Here, the third layer or more layers may be formed after the formation of the second porous Si layer.

This substrate was placed in an oxygen atmosphere at 400 ° C.
For 1 hour. Due to this oxidation, the inner wall of the hole of the porous Si layer was covered with the thermal oxide film. The surface of the porous Si layer is treated with hydrofluoric acid to remove only the oxide film on the surface of the porous Si layer while leaving the oxide film on the inner walls of the pores.
CVD (Chemical Vapor Depo)
Single-crystal Si was epitaxially grown by 0.25 μm by a position (method). The growth conditions are as follows.

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: 0.3 (μm / min) Further, as an insulating layer, an oxide film (SiO ₂ layer) of 100 nm was formed on the surface of the epitaxial Si layer by thermal oxidation.

Then, the two substrates were brought into close contact with the SiO ₂ layer so that the surface of a second quartz substrate as a light-transmitting substrate prepared separately was faced.
Heat treatment was performed for a long time, and the two substrates were bonded together. Here, by pre-treating both substrates with N ₂ plasma or the like before bringing both substrates into close contact with each other, the bonding strength was increased.

Next, the bonded substrate 101 formed as described above was separated by the separating device 100. The details are as follows.

The bonded substrate 101 is moved to the substrate holder 108,
It was vertically supported between the substrates 109 and pressed and held by the substrate holding unit 109. Then, the bonded substrate 101 is set at 8 rp.
m at a speed of m.

Next, the injection nozzle 112 is moved to the path 1 in FIG.
The robot was moved from the standby position 171 to the working position 172 along 70. Then, at the working position 172, the diameter of 0.20 m is directed toward the beveled concave portion of the bonded substrate 101.
Pure water at a pressure of 400 kgf / cm ² was injected in a vertical direction from the injection nozzle 112 of m for 2 minutes.

By this processing, the bonded substrate 101 is physically separated into two substrates. At this point, the separated two substrates are in close contact with each other via pure water.

Next, the jet pressure was set to 500 kgf /
cm ² , while scanning the spray nozzle 112 along the separation surface (that is, in the y-axis direction),
09 was retracted (moved in the positive direction of the x-axis) to separate the two substrates. Note that, when the substrate holding unit 109 is retracted, that is, when the two substrates are separated from each other, similar results were obtained with or without rotating each substrate.

As a result of the above processing, in addition to the SiO ₂ layer and the epitaxial Si layer formed on the surface of the first base,
Part of the porous Si layer was transferred to the second substrate side. Then, the porous Si layer remained on the surface of the first substrate.

Next, the porous S transferred on the second substrate
The i-layer was selectively etched while being stirred with a mixed solution of water, 49% hydrofluoric acid, and 30% aqueous hydrogen peroxide. At this time, the second
The single crystal Si of the substrate serves as an etch stop,
The porous Si was selectively etched and completely removed.

Non-porous Si by the above etching solution
The etching rate of the single crystal is extremely low, the selectivity with the etching rate of the porous layer is 10 ⁵ or more, and the etching amount of the non-porous layer (several tens of angstroms) is a practically acceptable amount.

Through the above steps, an SOI substrate having a Si oxide film and a single-crystal Si layer having a thickness of 0.2 μm formed on quartz could be formed. When the film thickness of the single-crystal Si layer after selectively etching the porous Si layer was measured at 100 points over the entire area in the plane, the film thickness was 201 n.
m ± 4 nm.

As a result of observation of a cross section with a transmission electron microscope, it was confirmed that no new crystal defects were introduced into the single-crystal Si layer, and good crystallinity was maintained.

Further, the resultant product was subjected to a heat treatment in hydrogen at 900 ° C. for 3 hours, and then the surface roughness was evaluated by an atomic force microscope. As a result, the mean square roughness in a 50 μm square region was obtained. Was about 0.2 nm. This is equivalent to a commercially available Si wafer.

Similar results were obtained when no oxide film was formed on the surface of the epitaxial layer.

On the other hand, the porous Si layer remaining on the first substrate side was selectively etched while being stirred with a mixture of water, 40% hydrofluoric acid and 30% hydrogen peroxide. Thereafter, the resulting product was subjected to surface treatment such as hydrogen annealing or surface polishing, so that it could be reused as the first substrate.

In general, a thin-film Si layer deposited on a light-transmitting substrate represented by quartz or the like has an amorphous or polycrystalline structure, reflecting the disorder of the crystal structure of the light-transmitting substrate. Become. Therefore, when a semiconductor device is manufactured by forming a Si layer on a light-transmitting substrate and using the substrate, it is difficult to obtain a high-performance device. Incidentally, a light-transmitting substrate is important in configuring a contact sensor or a projection-type liquid crystal image display device as a light receiving element. In order to further increase the density, resolution, and definition of pixels (picture elements) of sensors and display devices, high-performance driving elements are required.

Therefore, the production method as described in the above embodiment is extremely useful.

Example 6 The same experiment as described above was carried out by replacing the epitaxial layers in Examples 1 to 5 with a compound semiconductor represented by GaAs, and a good substrate was obtained.

(Others) The same experiment as in each of the above-mentioned embodiments was carried out except that the jet pressure was 200 to 3500 kgf / cm ^2.
And the diameter of the injection nozzle was set in the range of 0.1 mm to (half of the total thickness of the bonded substrate), and a good substrate was obtained.

As a method for growing an epitaxial layer on porous Si, in addition to the CVD method, for example, an MBE method,
A sputtering method, a liquid phase growth method and the like are suitable. The thickness of the epitaxial layer can be in the range of several nm to several hundred μm.

Further, a porous layer or an ion-implanted layer (separation layer)
An etching solution for selectively etching is, for example, 1) hydrofluoric acid, 2) hydrofluoric acid + alcohol, and 3) hydrofluoric acid, in addition to a mixed solution of water, 49% hydrofluoric acid, and 30% hydrogen peroxide solution. + Alcohol + hydrogen peroxide, 4) buffered hydrofluoric acid, 5) buffered hydrofluoric acid + alcohol, 6) buffered hydrofluoric acid + hydrogen peroxide, 7) buffered hydrofluoric acid + alcohol + hydrogen peroxide, 8) Hydrofluoric acid + nitric acid + acetic acid is preferred. Porous Si can be easily etched selectively due to its enormous surface area, and various etching solutions can be employed as described above.

Further, the other steps are not limited to the above embodiment, but can be carried out under various conditions.

Although the characteristic technical ideas have been described with reference to the specific embodiments and examples, the present invention is not limited to the matters described in these embodiments and examples. Instead, various modifications may be made within the scope of the technical idea described in the claims.

[0198]

According to the present invention, an object can be efficiently separated and separated.

In addition, according to the present invention, a good semiconductor substrate can be manufactured.

[0200]

[Brief description of the drawings]

FIG. 1 is a view illustrating a method of manufacturing an SOI substrate according to a preferred embodiment of the present invention in the order of steps.

FIG. 2 is a view conceptually showing a force acting on a bonded substrate depending on the presence or absence of a V-shaped groove.

FIG. 3 is a diagram showing a schematic configuration of a separation device according to a preferred embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a separation device according to a preferred embodiment of the present invention.

FIG. 5 is a diagram illustrating a first configuration example of an adjustment mechanism.

FIG. 6 is a diagram showing a second configuration example of the adjustment mechanism.

FIG. 7 is a diagram conceptually illustrating an example of a driving robot of an injection nozzle.

FIG. 8 is a view conceptually showing another example of a driving robot of the injection nozzle.

FIG. 9 is a diagram for explaining surface tension acting between two substrates.

FIG. 10 is a diagram schematically showing a principle of applying a force in a direction in which two substrates are separated by a fluid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Single-crystal Si substrate 12, 12 ', 12' 'Porous Si layer 12 13 Non-porous single-crystal Si layer 14 Single-crystal Si substrate 15 Insulating layer 100 Substrate separation apparatus 101 Bonded substrate 101a Substrate 101b Porous layer 101c Substrate 102, 103 Support portion 104, 105 Bearing 106, 107 Rotation axis 108, 109 Substrate holding portion 108a, 109a Vacuum suction mechanism 110, 111 Drive source 112 Injection nozzle 121 Piston rod 122 Air cylinder 131 Eccentric cam 132 Drive plate 160, 161 Drive robot

Continued on the front page (72) Inventor Takao Yonehara 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (54)

[Claims] 1. A separating apparatus for separating an object, comprising: separating means for separating an object to be separated into at least two objects by using a bundled fluid; and injecting a fluid between the separated objects. And a separating means for separating the objects while separating. 2. An object to be separated is a plate-like object, and said separating means cuts the plate-like object in a plane direction and separates the plate-like object into two plate-like objects. The separation device according to claim 1. 3. The apparatus according to claim 1, further comprising a pair of holding portions for holding the object so as to be sandwiched from both sides when separating the object, and for holding each separated object even after the object is separated. The separation device according to claim 2, characterized in that: 4. The separation device according to claim 3, wherein the pair of holding units hold the object while pressing the object when separating the object. 5. The apparatus according to claim 3, wherein said separating means separates each separated object by widening an interval between said pair of holding portions after the object is separated by said separating means. The separation device according to any one of the preceding claims. 6. The separation apparatus according to claim 5, wherein the pair of holding units have an adsorption mechanism for adsorbing each separated object. 7. The separation device according to claim 6, wherein the suction mechanism includes a vacuum suction mechanism. 8. An ejector for ejecting a bundle of fluids, wherein the separating means separates an object to be separated by the fluid ejected from the ejector, and the separating means ejects the fluid from the ejector. 2. The method according to claim 1, wherein each of the objects is separated while the fluid to be injected is injected between the separated objects.
The separation device according to claim 7. 9. The separation apparatus according to claim 1, wherein the object to be separated has a weak layer inside as a separation layer. 10. The separation device according to claim 9, wherein the fragile layer is a porous layer. 11. The separation device according to claim 9, wherein the fragile layer is a layer having microbubbles. 12. A separation device for separating an object, comprising: an ejection unit for ejecting a bundle of fluids; and a set of holding units for holding the object, wherein the set of holding units is used to separate the object. While holding the object, the object is separated while ejecting a fluid from the ejecting unit toward the object, and the separated object is ejected from the ejecting unit toward the space between the separated objects. A separation device, wherein the pair of holding units are moved so as to separate each substrate. 13. The object to be separated has a plate shape, and
13. The set of holding portions, when separating the object, holds the object so as to sandwich the object from both sides.
The separation device according to claim 1. 14. The separation apparatus according to claim 13, wherein the pair of holding units hold the object while pressing the object when separating the object. 15. The separation apparatus according to claim 14, wherein the one set of holding units has a suction mechanism that suctions each separated object. 16. The separation device according to claim 15, wherein the suction mechanism includes a vacuum suction mechanism. 17. The separation apparatus according to claim 12, wherein the object to be separated has a weak layer inside as a separation layer. 18. The separation device according to claim 17, wherein the fragile layer is a porous layer. 19. The separation device according to claim 17, wherein the fragile layer is a layer having microbubbles. 20. A separation method for separating objects, comprising: separating a body into at least two objects while injecting a bundle of fluids toward the object to be separated; and separating each of the separated objects. A separating step of separating each object while injecting a fluid therebetween. 21. The object to be separated is plate-shaped, and in the separation step, the plate-shaped object is cut in a plane direction and separated into two plate-shaped objects. The separation method described in 1. 22. The separation method according to claim 21, wherein in the separation step, the object to be separated is held so as to be sandwiched from both sides. 23. The method of claim 23, wherein in the separating step, the separated substrates are separated from each other by widening an interval between the two holding portions in a state where the separated substrates are attracted to the holding portions of the respective substrates. 23. The separation method according to claim 21 or 22. 24. The separation according to claim 20, wherein in the separation step and the separation step, a bundle of fluid ejected from the same ejection unit is used. Method. 25. The separation method according to claim 20, wherein the object to be separated has a weak layer inside as a separation layer. 26. The method according to claim 25, wherein the fragile layer is a porous layer. 27. An object to be separated has a layer composed of a semiconductor substrate, and the porous layer is a layer formed by subjecting the semiconductor substrate to an anodizing treatment. A method according to claim 26. 28. The separation method according to claim 25, wherein the fragile layer is a layer having microbubbles. 29. The object to be separated has a layer composed of a semiconductor substrate, and the layer having microbubbles is a layer formed by implanting ions into the semiconductor substrate. Item 30. The separation method according to Item 28. 30. The separation method according to claim 20, wherein water is used as the fluid. 31. Any one of claims 1 to 19
A separation method, comprising separating an object by using the separation device described in the above section. 32. A method for manufacturing a semiconductor substrate, wherein the method according to claim 20 is applied to a part of the steps to manufacture a semiconductor substrate. 33. A method for manufacturing a semiconductor substrate, comprising:
Forming a substrate, bonding the first substrate and the second substrate with the non-porous layer inside, to form a bonded substrate, and applying a bundled fluid to the bonded substrate. Separating the bonded substrate into two substrates while spraying the substrate toward the vicinity of the porous layer, and separating the substrates while injecting a fluid between the separated substrates. A method for manufacturing a semiconductor substrate, comprising: 34. The method according to claim 33, wherein the step of forming the first substrate includes a step of forming a porous layer on one surface of the substrate by performing anodizing treatment on the substrate. The method for producing a semiconductor substrate according to the above. 35. The step of forming the first substrate, the step of forming a porous layer on one surface of the single-crystal silicon substrate by performing anodizing treatment on the single-crystal silicon substrate; The method for producing a semiconductor substrate according to claim 33, comprising: a step of epitaxially growing a single crystal silicon layer as a non-porous layer. 36. The method according to claim 35, wherein the step of forming the first substrate further includes a step of forming an insulating layer on the epitaxially grown single crystal silicon layer. . 37. The method according to claim 36, wherein the insulating layer is made of silicon oxide. 38. The semiconductor according to claim 37, wherein in the step of forming the insulating layer, an insulating layer made of silicon oxide is formed by oxidizing a surface of the single crystal silicon layer epitaxially grown. A method for manufacturing a substrate. 39. The method according to claim 33, wherein the second base is made of a silicon substrate. 40. The method of manufacturing a semiconductor substrate according to claim 33, wherein said second substrate is formed of a light-transmitting substrate. 41. The method according to claim 33, further comprising, after the step of separating the separated substrates, removing a porous layer remaining on the side of the second substrate.
The method for manufacturing a semiconductor substrate according to any one of the above items. 42. The method according to claim 41, further comprising, after the step of removing the porous layer, a step of flattening the surface of the resultant product. 43. The method according to claim 33, further comprising, after the step of separating the separated substrates, a step of removing the porous layer remaining on the first substrate side and making the porous layer reusable.
43. The method of manufacturing a semiconductor substrate according to claim 42. 44. A method of manufacturing a semiconductor substrate, comprising the steps of: implanting ions at a predetermined depth from the surface of a single crystal semiconductor substrate to form a first substrate having a microbubble layer formed therein; Laminating a second substrate on the surface side of the first substrate to form a bonded substrate; and bonding the bonded substrate while injecting a bundled fluid toward the vicinity of the microbubble layer of the bonded substrate. A method of manufacturing a semiconductor substrate, comprising: separating a substrate into two substrates; and separating each substrate while injecting a fluid between the separated substrates. 45. The method according to claim 44, wherein the step of forming the first base includes the step of forming an insulating layer on the surface of the base before the step of implanting ions into the base. A method for manufacturing a semiconductor substrate. 46. The method according to claim 45, wherein the insulating layer is made of silicon oxide. 47. The semiconductor according to claim 46, wherein in the step of forming the insulating layer, an insulating layer made of silicon oxide is formed by oxidizing a surface of the base made of the single crystal semiconductor. A method for manufacturing a substrate. 48. The method of manufacturing a semiconductor substrate according to claim 44, wherein said second substrate is made of a silicon substrate. 49. The method of manufacturing a semiconductor substrate according to claim 44, wherein the second substrate is formed of a light-transmitting substrate. 50. The method according to claim 44, further comprising, after the step of separating the separated substrates, a step of removing a microbubble layer remaining on the second substrate side.
10. The method for manufacturing a semiconductor substrate according to any one of items 9 to 9. 51. After the step of removing the microbubble layer,
The method for manufacturing a semiconductor substrate according to claim 50, further comprising a step of flattening a surface of a resultant product. 52. The method according to claim 4, further comprising, after the step of separating the separated substrates, a step of removing the microbubble layer remaining on the first substrate side and making the microbubble layer reusable.
The method for manufacturing a semiconductor substrate according to any one of claims 4 to 51. 53. The method for manufacturing a semiconductor substrate according to claim 33, wherein water is used as the fluid. 54. A semiconductor substrate that can be formed by the manufacturing method according to claim 33.