Bonding and peeling method for thin substrates, manufacturing method for thin substrates, thin substrate, peeling device, and bonding device

Abstract

To provide a peeling technique capable of easily peeling a substrate having an electronic element formed on its surface and a transfer substrate for transferring the substrate from each other, which are bonded to each other.SOLUTION: A method for bonding and peeling a substrate 3 having an electronic element 4 formed thereon and a transport substrate 1 for transporting the substrate 3 includes the steps of bonding bonding surfaces of the substrate 3 and the transport substrate 1 with an inorganic material layer 2 interposed therebetween, and peeling the substrate 3 and the transfer substrate 1 from each other by interposing water between the bonding surfaces.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bonding and peeling method for a thin substrate, a manufacturing method for a thin substrate, a thin substrate, a peeling device, and a bonding device. [Background technology]

[0002] Organic electroluminescence (OLED) elements (OLED elements) are formed using a planar light-emitting layer made of organic compounds formed on a transparent substrate, and are increasingly being put to practical use in applications such as thin displays. Compared to liquid crystal displays, OLED displays have a wider viewing angle, lower power consumption, and are flexible enough to be bent, making them highly commercially viable. Furthermore, process development is also underway in the fields of three-dimensional IC packaging and MEMS as a manufacturing method that uses thin substrates (1 μm thick Si wafers).

[0003] Wafer thicknesses are typically around 0.5-1 mm for ease of handling during the manufacturing process. For typical silicon wafers, the external dimensions are standardized by industry organizations such as SEMI, with thicknesses of 0.625 mm for a 150 mm (6 inch) diameter wafer, 0.725 mm for a 200 mm (8 inch) wafer, and 0.775 mm for a 300 mm (12 inch) wafer. However, the thin substrates being used are generally between 0.5 μm and 0.2 mm thick, making them difficult to transport in typical manufacturing processes. Furthermore, substrate sizes range from as small as chip size (4 inches square) to as large as over 1 m square, making it difficult to transport thin substrates using robots during device manufacturing.

[0004] One possible solution is to use a glass substrate, film, or wafer with a thickness of 0.1 mm to 1.1 mm as the transport substrate, and then attach the above-mentioned thin substrate to its surface for transport. This method has the advantage that the substrate thickness can be transported using existing equipment as is. However, the transport substrate must be peeled off after the device is completed.

[0005] There are three types of thin substrates. One is thin glass, and the other is heat-resistant film, typically polyimide. This type of film also includes films created by applying varnish directly to a carrier substrate, baking it, and then forming it into a film. The third type is wafers. In some cases, wafers are protected with adhesive tape. In this case, the substrate is a laminate of wafer and film.

[0006] Currently proposed transport methods use glass or wafers as the transport carrier. In the case of thin glass, the method is to keep the carrier glass surface clean and bond them directly to each other, taking advantage of the characteristics of glass-to-glass. In the case of heat-resistant film, a film that causes destruction when irradiated with a laser is formed between the carrier glass and the film, and after bonding, it is peeled off by laser irradiation. In addition, when the thin substrate is a wafer, non-contact transport methods and special chucking methods have been proposed, but there are limits to the thickness that can be transported. In reality, the realizable range is a thickness of around 100 μm, and there is no transport method for thicknesses such as 1 μm.

[0007] In this case, a carrier substrate can be used. However, there is no good method for peeling. In the case of wafers, polishing may be used to thin them. In this case, adhesive tape is applied to the wafer to prevent cracking or chipping after polishing. In this case, it has also been suggested to use glass as a carrier.

[0008] For example, in the case of displays, thin substrates are heated to around 300 to 500°C in the TFT formation process. Also, in semiconductor processes such as wafers, there is an annealing step in which they are heated to over 800°C. Because they undergo heated steps, there is no effective method for peeling the thin substrate from the carrier substrate to which it is attached.

[0009] Meanwhile, as devices become thinner, there has been a growing demand for temporary bonding and peeling technologies. Current temporary bonding and peeling methods involve applying a tape that reacts to ultraviolet light, and then peeling it off with ultraviolet light after all other processes have been completed. Another method, known as laser lift-off, involves focusing a laser on the bonding interface to remove the material (used to peel off the carrier glass and PI varnish of flexible organic light-emitting diodes). However, these technologies require the use of materials that are transparent to ultraviolet light. This technology is an additional application when using a silicon wafer as the carrier. This technology is a solution when ultraviolet light is not effective or when organic materials cannot be used as a release film. A major application is the bonding and peeling of silicon wafers and interposers (glass or silicon).

[0010] For example, Patent Document 1 discloses a method of easily separating a thin substrate and a transportation substrate by bonding them together via an inorganic material layer. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] International Publication No. 2016 / 010106 Summary of the Invention [Problem to be solved by the invention]

[0012] However, there is a need for a further method for easily separating the thin substrate from the carrier substrate.

[0013] The present invention has been made in view of the above, and aims to provide a separation technique that can easily separate a substrate having electronic elements formed on its surface from a transport substrate for transporting the substrate, which are joined together. [Means for solving the problem]

[0014] In order to solve the above-mentioned problems and achieve the object, the present invention provides a method for bonding and peeling a substrate having electronic elements formed on its surface to a transport substrate for transporting the substrate, the method comprising bonding the bonding surfaces of the substrate and the transport substrate via an inorganic material layer, and peeling the bonding surfaces of the substrate and the transport substrate with water interposed therebetween.

[0015] In one aspect of the present invention, the water is subjected to ultrasonic vibration.

[0016] In one aspect of the present invention, the method includes applying ultrasonic vibrations to the bonding surfaces after placing water between the bonding surfaces.

[0017] In one aspect of the present invention, the inorganic material layer has at least one flow path formed therein for allowing water to be present on the bonding surface.

[0018] In one aspect of the present invention, the transfer substrate has at least one flow hole formed therein for allowing water to pass through the joining surface.

[0019] In one aspect of the present invention, the method includes pressing and peeling the substrate with a peeling member inserted into the through hole.

[0020] In one aspect of the present invention, the inorganic material layer contains any one or any combination of silicon, aluminum oxide, titanium oxide, copper, silicon nitride, aluminum, titanium, nickel, tin, and graphite.

[0021] In one aspect of the present invention, the substrate and the carrier substrate are made of any one of glass, silicon, a compound semiconductor, and a polymer film, or a combination thereof.

[0022] Furthermore, the method for manufacturing a substrate having electronic elements formed on its surface of the present invention includes forming an inorganic material layer on at least one of a bonding surface of the substrate to which a transport substrate is to be bonded and a bonding surface of the transport substrate for transporting the substrate, pressing the substrate and the transport substrate against each other to bond the substrate and the transport substrate via the inorganic material layer, and peeling the substrate and the transport substrate by placing water between the bonding surfaces.

[0023] In one aspect of the present invention, the water is subjected to ultrasonic vibration.

[0024] In one aspect of the present invention, the method includes applying ultrasonic vibrations to the bonding surfaces after placing water between the bonding surfaces.

[0025] In one aspect of the present invention, the inorganic material layer has at least one flow path formed therein for allowing water to be present on the bonding surface.

[0026] In one aspect of the present invention, the transfer substrate has at least one flow hole formed therein for allowing water to pass through the joining surface.

[0027] In one aspect of the present invention, the method includes pressing and peeling the substrate with a peeling member inserted into the through hole.

[0028] In one aspect of the present invention, the inorganic material layer contains any one or any combination of silicon, aluminum oxide, titanium oxide, copper, silicon nitride, aluminum, titanium, nickel, tin, and graphite.

[0029] In one aspect of the present invention, the substrate and the carrier substrate are made of any one of glass, silicon, a compound semiconductor, and a polymer film, or a combination thereof.

[0030] In one aspect of the present invention, the method includes activating the surface of the inorganic material layer by irradiating it with particles having a predetermined kinetic energy before the bonding.

[0031] In one aspect of the present invention, the bonding is performed in a vacuum atmosphere or a gas atmosphere containing an inert gas.

[0032] One aspect of the present invention includes a thin substrate manufactured by the above manufacturing method.

[0033] The peeling device of the present invention includes a container for storing water, an ultrasonic generator for applying ultrasonic waves to the water in the container, a mounting table that is movable within the container between a mounting position for placing a substrate assembly and an immersion position for immersing the substrate assembly in water, and a liquid level adjustment mechanism for maintaining the water level in the container at a predetermined water level.

[0034] Furthermore, a peeling device according to another aspect of the present invention includes a container for storing water, an ultrasonic application stage on which a substrate assembly is placed when ultrasonic waves are applied to the substrate assembly, an ultrasonic generator that applies ultrasonic waves to the substrate assembly, and a transport robot that transports the substrate assembly between the container and the ultrasonic application stage, wherein the container includes a mounting stage that is movable within the container between a mounting position where the substrate assembly is placed and an immersion position where the substrate assembly is immersed in water, and a liquid level adjustment mechanism that maintains the water level in the container at a predetermined position.

[0035] The bonding apparatus of the present invention comprises a transfer substrate load lock chamber for loading and unloading a transfer substrate, a substrate load lock chamber for loading and unloading a substrate, a transfer chamber in which a transfer robot is installed, a sputtering chamber for forming an inorganic material layer on the transfer substrate and the substrate directly or via a mask, a mask chamber that is provided in communication with the sputtering chamber and stores a mask that covers the transfer substrate and the substrate, an inert gas treatment chamber that exposes the transfer substrate and the substrate to an inert gas atmosphere, an activation treatment chamber that performs an activation treatment on the transfer substrate and the substrate with an ion beam, and a bonding chamber that bonds the transfer substrate and the substrate, and the transfer substrate load lock chamber, the substrate load lock chamber, the sputtering chamber, the inert gas treatment chamber, the activation treatment chamber, and the bonding chamber are connected to the transfer chamber by gate valves so that the transfer substrate and the substrate can be transported among them. [Effects of the Invention]

[0036] According to the present invention, the substrate and the substrate for transportation are bonded via an inorganic material layer, electronic elements are formed on the substrate, and then the substrate and the substrate for transportation are peeled off by placing water between the bonding surfaces of the substrate and the substrate for transportation, thereby achieving the effect of easily peeling the substrate and the substrate for transportation. [Brief explanation of the drawings]

[0037] [Figure 1] 1A to 1C are conceptual diagrams illustrating steps of a manufacturing method according to an embodiment of the present invention. [Figure 2] 1 is a conceptual side view of a substrate assembly according to an embodiment of the present invention. [Figure 3] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 4] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 5] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 6] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 7] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 8] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 9] 1A to 1C are schematic diagrams illustrating steps of a peeling method according to an embodiment of the present invention. [Figure 10] 1 is a schematic diagram of a peeling device according to an embodiment of the present invention. [Figure 11] 1 is a schematic diagram of a peeling device according to an embodiment of the present invention. [Figure 12] 1 is a schematic diagram of a peeling device according to an embodiment of the present invention. [Figure 13] 1 is a schematic diagram of a peeling device according to an embodiment of the present invention. [Figure 14] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 15] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 16] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 17] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 18] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 19] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 20] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 21] 5A and 5B are diagrams showing flow paths formed on a bonding surface between a substrate and a transfer substrate according to an embodiment of the present invention. [Figure 22] 1 is a schematic diagram of a joining device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention will be described below by way of embodiments, but it is obvious that the present invention is not limited to these specific embodiments.

[0039] (First embodiment) The manufacturing method of this embodiment is a method for manufacturing a substrate having electronic elements formed on its surface, and includes a formation step of forming an inorganic material layer 2 on at least one of the joining surfaces of a substrate 3 having electronic elements 4 formed on its surface and a transport substrate 1 for transporting the substrate 3; a bonding step of pressing the substrate 3 and the transport substrate 1 against each other to bond the substrate 3 and the transport substrate 1 via the inorganic material layer 2; and a peeling step of peeling the substrate 3 and the transport substrate 1 from each other with water interposed between their joining surfaces.

[0040] In the manufacturing method having the above configuration, by bonding the substrate and the transfer substrate via the inorganic material layer, the substrate and the transfer substrate can be easily separated later by placing water between their bonded surfaces even if a heat treatment at, for example, 300 to 500° C. is performed in a step after the substrate bonding. Alternatively, depending on the material and conditions, the substrate and the transfer substrate may be easily separated even if a heat treatment at an even higher temperature is performed.

[0041] The above manufacturing method may further include an electronic element forming step of forming electronic elements 4 on the substrate before or after the bonding step and before the peeling step. Also, the method may further include a sealing step of sealing the electronic elements with another substrate.

[0042] Examples of electronic elements 4 formed on the substrate 3 include, but are not limited to, TFTs and organic EL elements. When the electronic elements 4 are, for example, TFTs (thin film transistors), their formation process includes a heating step at approximately 300°C to 500°C.

[0043] 1 is a diagram illustrating an example of a manufacturing method according to this embodiment, in which an inorganic material layer 2 is formed on a transportation substrate 1.

[0044] (a) Preparation process of the transfer substrate A transfer board 1 is prepared for placing a substrate 3 on which electronic elements 4 are to be formed.

[0045] (b) Inorganic material layer formation process An inorganic material layer 2 is formed on the surface (the surface to be bonded to the substrate 3) of a transportation substrate 1 for transporting the substrate 3.

[0046] (c)Joining process The substrate 3 and the transportation substrate 1 are pressed against each other to bond the substrate 3 and the transportation substrate 1 via the inorganic material layer 2, thereby forming a substrate assembly.

[0047] (d) Electronic element formation process An electronic element 4 is formed on the substrate 3 of the substrate assembly. Thereafter, a sealing process is performed in which another substrate (cover-side substrate 5) is bonded to seal the electronic element 4 of the substrate assembly, thereby completing the device.

[0048] (e) Peeling process The substrate 3 on which the electronic elements 4 are formed and the transport substrate 1 are peeled off by interposing water between their bonding surfaces. The interposing water between the bonding surfaces will be described in detail later. For example, as shown in FIG. 1(e), the bonded assembly of the substrate 3 and the transport substrate 1 can be easily peeled off by immersing the assembly in a container 13 containing water 11 until the water penetrates the bonding surface. Pure water, for example, is used as the water used in the peeling step. This step yields a device including the substrate 3 on whose surface the electronic elements 4 are formed. In this example, the inorganic material layer 2 remains on the transport substrate 1 side. Furthermore, even if the peeling step is performed in water, it does not have any effect on the electronic elements 4 already formed in the electronic element formation step.

[0049] In the above manufacturing method, the inorganic material layer 2 is formed on the transportation substrate 1, but the inorganic material layer 2 may be formed on the substrate 3, followed by the (c) bonding step, (d) electronic element forming step, and (e) peeling step. Even in this case, the substrate 3 and the transportation substrate 1 can be easily peeled off by applying water to the bonding surface between the substrate 3 on which the electronic elements 4 are formed and the transportation substrate 1.

[0050] The above manufacturing method may further include a surface activation step, which will be described later, between steps (b) and (c).

[0051] The above manufacturing method may further include a surface activation step, prior to the bonding step, of activating the bonding surface of at least one of the substrate 3 or the transport substrate 1 by irradiating it with particles having a predetermined kinetic energy.

[0052] Alternatively, the above manufacturing method may further include a surface activation step, prior to the bonding step, of activating the surface of the inorganic material layer 2 by irradiating it with particles having a predetermined kinetic energy.

[0053] By performing the surface activation treatment in the surface activation step, the bonding strength of the bonding interface between the transportation substrate 1, the inorganic material layer 2 or the substrate 3 can be increased in the substrate bonding step.

[0054] By colliding particles with a certain kinetic energy and physically ejecting the material that forms the bonding surface (a sputtering phenomenon), the surface layer, including oxides and contaminants, can be removed, exposing a new surface with high surface energy, i.e., an active inorganic material layer.

[0055] The particles used in the surface activation treatment can be rare gases or inert gases such as neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), helium (He), etc. These rare gases are unlikely to chemically react with the materials that make up the bonding surfaces they collide with, so they do not significantly change the chemical properties of the bonding surfaces by forming compounds, etc.

[0056] The particles to be collided with the bonding surface to be surface activated can be given a predetermined kinetic energy by accelerating the particles toward the bonding surface using a particle beam source or a plasma generator.

[0057] The kinetic energy of the particles colliding with the bonding surface to be surface activated is preferably 1 eV to 2 keV. It is believed that this kinetic energy efficiently causes sputtering of the surface layer. A desired kinetic energy value can be set within the above kinetic energy range depending on the thickness and material properties of the surface layer to be removed, the material of the newly formed surface, and other factors.

[0058] A particle beam source can also be used to provide particles with a predetermined kinetic energy. The particle beam source may have a background pressure of, for example, 1×10 -8 It operates in a relatively high vacuum, such as below 100 Pa (Pascal). By operating a vacuum pump to create a relatively high vacuum, materials removed from the surface of the metal area are efficiently evacuated out of the atmosphere.

[0059] This prevents unwanted materials from adhering to the exposed new surface. Furthermore, the particle beam source can apply a relatively high acceleration voltage, which imparts high kinetic energy to the particles. Therefore, it is believed that the surface layer can be removed efficiently and the new surface can be activated.

[0060] Alternatively, if the background pressure is 1×10 -8 The surface activation treatment may be carried out in a vacuum or reduced pressure atmosphere, that is, a pressure of at least 100 Pa but less than atmospheric pressure.

[0061] The particle beam source may be an ion beam source that emits an ion beam or a neutral atom beam source that emits a neutral atom beam, and may be a cold cathode ion source.

[0062] A fast atom beam source (FAB) can be used as a neutral atom beam source. A fast atom beam source (FAB) typically generates a plasma of a rare gas, applies an electric field to the plasma, extracts positive ions of ionized particles from the plasma, and passes them through an electron cloud to neutralize them.

[0063] In this case, for example, when argon (Ar) is used as the rare gas, the power supplied to the fast atom beam source (FAB) may be set to 1.5 kV (kilovolts) and 15 mA (milliamperes), or may be set to a value between 0.1 and 500 W (watts). For example, when the fast atom beam source (FAB) is operated at 100 W to 200 W (watts) and a fast atom beam of argon (Ar) is irradiated for about two minutes, the oxides, contaminants, etc. (surface layer) on the bonding surface are removed, and a new surface can be exposed.

[0064] In the present invention, the particles used for surface activation may be neutral atoms or ions, or may be radical species, or may be a particle group containing a mixture of these.

[0065] The removal rate of the surface layer may vary depending on the operating conditions of each plasma or beam source or the kinetic energy of the particles. Therefore, the treatment time required for the surface activation treatment must be adjusted. For example, the treatment time for the surface activation treatment may be determined by a surface analysis method such as Auger Electron Spectroscopy (AES) or X-ray Photoelectron Spectroscopy (XPS), and may be set to the time until the presence of oxygen or carbon in the surface layer is no longer detected.

[0066] A plasma generator can also be used to impart a predetermined kinetic energy to the particles. By applying an alternating voltage to the bonding surfaces of the substrates, plasma containing particles is generated around the bonding surfaces, and the cations of the ionized particles in the plasma are accelerated toward the bonding surfaces by the voltage, thereby imparting the predetermined kinetic energy. Because plasma can be generated in a low-vacuum atmosphere of a few pascals (Pa), the vacuum system can be simplified and processes such as evacuation can be shortened.

[0067] In the above manufacturing method, the surface of the substrate may be selectively subjected to a surface activation treatment before the bonding step of bonding the substrate 3 and the transportation substrate 1. Furthermore, before the bonding step, a portion of the inorganic material layer may be selectively subjected to surface activation.

[0068] The part of the inorganic material layer is, for example, the outer periphery of the substrate 3, and by subjecting only the outer periphery to surface activation treatment, the bonding strength of the outer periphery relative to the center of the substrate 3 is preferably increased.

[0069] In the above manufacturing method, multiple inorganic material layers of different types may be formed. For example, different types of inorganic material layers may be formed in the central portion and the peripheral portion of the substrate 3. This allows a difference in bonding strength between the central portion and the peripheral portion of the substrate 3. This makes it possible to control the bonding strength according to the substrate. Furthermore, a surface activation treatment may be selectively performed on some of these inorganic material layers.

[0070] The transfer substrate 1 may be formed from plate-like or film-like glass, a heat-resistant film, a wafer, or a composite material thereof. More specifically, if the substrate 3 is thin glass, the transfer substrate 1 is preferably a heat-resistant film, a glass substrate, or a substrate in which a heat-resistant film is attached to glass; if the substrate 3 is a heat-resistant film, the transfer substrate 1 is preferably glass; if the substrate 3 is a wafer, the transfer substrate 1 is preferably a wafer or glass. The transfer substrate 1 may be provided in a sheet or rolled form.

[0071] From the viewpoint of being able to use existing facilities, the thickness of the transfer substrate 1 is preferably 0.1 mm or more and 1.1 mm or less.

[0072] The inorganic material layer 2 may contain any one or a combination of silicon, aluminum oxide, titanium oxide, copper, silicon nitride, aluminum, titanium, nickel, tin, and graphite. Specific examples of the inorganic material layer 2 include Al2O3 (aluminum oxide), TiO2 (titanium oxide), NiO (nickel oxide), Ag2O (silver oxide), and SiO2 (silicon dioxide). This allows the substrate 3 and the transfer substrate 1 to be easily separated during the separation process in water.

[0073] A plurality of inorganic material layers 2 may be formed, that is, a structure in which a first inorganic material layer and a second inorganic material layer are laminated may be used.

[0074] The inorganic material layer 2 is preferably formed by a deposition method such as plasma enhanced chemical vapor deposition (PECVD) or sputter deposition, but is not limited to these. When forming the inorganic material layer 2, a predetermined mask can be used to form it only in a predetermined region. Furthermore, as will be described later, a flow path can be formed on the bonding surface to allow water to be present.

[0075] In addition, when forming the inorganic material layer 2 by depositing a predetermined inorganic material layer material by plasma enhanced chemical vapor deposition (PECVD), sputter deposition, or the like, inorganic material layer materials other than the predetermined inorganic material layer material may be mixed.

[0076] For example, when a particle beam is irradiated onto a sputter target to cause a predetermined inorganic material layer material of the sputter target to be released from the sputter target and perform sputter deposition, a target made of an inorganic material layer material other than the predetermined inorganic material layer material may be placed in the path of the particle beam.

[0077] This allows sputter deposition of a mixed metal oxide material in which a predetermined metal oxide material is mixed with a metal oxide material other than the predetermined metal oxide material.

[0078] The inorganic material layer 2 used for bonding the substrate 3 and the transportation substrate 1 is preferably adjusted in thickness and quality so that it can be easily peeled off after undergoing a heating step, a cleaning step, or the like.

[0079] The substrate 3 and the transport substrate 1 are preferably made of glass. Alternatively, the substrate 3 and the transport substrate 1 are preferably films made of organic materials such as PI (polyimide), PEN (polyethylene naphthalate), PET (polyethylene terephthalate), or COP (cycloolefin polymer). Alternatively, the substrate 3 and the transport substrate 1 are preferably wafers made of silicon, compound semiconductors (e.g., GaP, GaAs, InP, GaN), or the like.

[0080] The thickness of the substrate 3 is preferably 0.5 μm or more and 0.5 mm or less, and more preferably 0.5 μm or more and 0.2 mm or less. The substrate 3 may be supplied in the form of a sheet or roll.

[0081] In the above manufacturing method, the substrate may be composed of multiple layers, including a layer made of glass and a layer made of an organic material. In this case, the substrate may be composed of a layer made of glass and a layer made of an organic material, and the side of the layer made of the organic material may be bonded to a transfer substrate.

[0082] For example, as shown in Figure 2, a laminated substrate 9 made up of a glass layer 7 and an organic material layer 8 may be used. In this case, a combination of glass and PI is particularly preferred as the materials for forming the glass layer 7 and the organic material layer 8. To bond the glass layer 7 and the organic material layer 8, it is preferable to form an inorganic material in either the glass layer 7 or the organic material layer 8, and to use a method of surface activation by applying a predetermined amount of energy to the surface of the inorganic material. This is because using an adhesive or the like can cause problems such as solidification during the heating process.

[0083] Conventionally, a substrate for transportation was used once and then thrown away, but according to the manufacturing method of the above embodiment, the substrate for transportation can be reused because the substrate is not damaged by laser irradiation or the like and no organic adhesive is used.

[0084] In the manufacturing method according to the above embodiment, the substrate bonding step may be performed in a vacuum atmosphere or an inert gas atmosphere. This makes it possible to easily control the bonding strength between the transfer substrate 1 and the substrate 3. The inert gas is preferably nitrogen gas.

[0085] In the manufacturing method according to the above embodiment, before the substrate bonding step, the bonding surfaces of the substrate 1 and the transportation substrate 3 are exposed to an inert gas atmosphere. This makes it difficult for the bonding strength between the transportation substrate 1 and the substrate 3 to change due to heating. The inert gas is preferably nitrogen gas.

[0086] In the manufacturing method according to the above embodiment, the substrate bonding step is performed at a background pressure of 1×10 -8 The heating may be carried out in a vacuum or reduced pressure atmosphere, that is, a pressure of 100 Pa or more but less than atmospheric pressure.

[0087] Alternatively, for example, substrates may be bonded together without undergoing the aforementioned surface activation process. For example, an inorganic material layer formed by vapor deposition in a vacuum has a high surface energy because its surface is not oxidized or contaminated by impurities. By contacting the surface of such an inorganic material layer with the surface of another substrate, a bonding interface with relatively high strength can be formed.

[0088] According to the method for joining and peeling a substrate and a transport substrate of this embodiment, the substrate and the transport substrate are joined via an inorganic material layer, electronic elements are formed on the substrate, and then peeling is performed with water interposed between the bonding surfaces of the substrate and the transport substrate, thereby making it possible to easily peel the substrate and the transport substrate.

[0089] 3 to 6 are schematic diagrams illustrating the peeling method of this embodiment. As shown in Fig. 3, a laminate 10 has a transportation substrate 1 and a substrate 3 bonded together via an inorganic material layer 2, and substrates 14a and 14b, on the surface of which electronic elements are formed, are laminated. A container 13 containing water 11 is placed below the laminate. Ultrasonic waves are applied to the water 11.

[0090] Next, as shown in FIG. 4, the sides of the substrate 3 and the substrates 14a and 14b are covered with a sealing material 15 to prevent water intrusion. The laminate 10, with the sides of the substrates 3 and 14a and 14b covered with the sealing material 15, is then submerged in a container, as shown in FIG. 5, so that the bonding surfaces of the transfer substrate 3 and the substrate 1 are positioned in the water to which ultrasonic waves are applied. This causes the ultrasonically excited water to permeate from the edges of the bonding surfaces, and as shown in FIG. 6, the transfer substrate 1 on which the inorganic material layer 2 is formed is separated from the substrate 3 on which the electronic elements are formed, completing the delamination process. In this process, pure water may be used, for example. The ultrasonic waves applied to the water may be selected from the low-frequency band (20 kHz-100 kHz), the medium-frequency band (78 kHz-430 kHz), or the high-frequency band (500 kHz-5 MHz) as appropriate, depending on the bonding surfaces to be delaminated.

[0091] As described above, in this embodiment, the bonding surfaces of a substrate having electronic elements formed on its surface and a substrate for transportation are bonded via an inorganic material layer, and delamination is performed by interposing water between the bonding surfaces of the substrate and the substrate for transportation. Ultrasonic waves are applied to the interposed water, and the water penetrates between the bonding surfaces to delaminate the substrate and the substrate for transportation. Therefore, the substrate and the substrate for transportation can be easily delaminated without applying physical stress. Since no physical stress is used, it is possible to delaminate the thin substrate from the substrate for transportation without damaging it. Damage to the substrate for transportation can also be prevented, making it possible to reuse the substrate for transportation, and establishing an economically efficient production process.

[0092] (Second embodiment) This embodiment differs from the first embodiment in the peeling method. Figs. 7 to 9 are schematic diagrams illustrating the peeling method of this embodiment. As shown in Fig. 7, a laminate 10 has a transportation substrate 1 and a substrate 3 bonded together via an inorganic material layer 2, and substrates 14a and 14b, on the surface of which electronic elements are formed, are laminated. A container 13 containing water 11 is placed below this laminate. Ultrasonic waves are applied to the water 11.

[0093] In this embodiment, the transport substrate 1 is further formed with at least one through hole 17 for allowing water to pass through the bonding surface between the transport substrate 1 and the substrate 3. A peeling member 19 to be inserted into the through hole 17 is disposed in the container 13. Next, as shown in FIG. 8 , the transport substrate 1 side of the laminate 10 is immersed in water 11, the peeling member 19 is inserted into the through hole 17, and the substrate 1 is pressed. This promotes the penetration of the water 11 to which ultrasonic waves have been applied into the bonding surface, and the transport substrate 1 and the substrate 3 are peeled off from each other as shown in FIG. 9 .

[0094] In this embodiment, ultrasonically applied water is placed on the bonding surface between the transport substrate 1 and the substrate 3, and the transport substrate 1 is provided with flow holes 17. Water is also applied to the bonding surface through the flow holes 17, and at the same time, a peeling member 19 is inserted into the flow holes 17 and presses against the substrate 1, thereby facilitating the peeling between the transport substrate 1 and the substrate 3. Therefore, the transport substrate 1 and the substrate 3 can be peeled off efficiently without taking much time. By pressing the substrate 3 with the peeling member 19 through the evenly arranged multiple flow holes 17, it is possible to apply an even pressure to the substrate 3, preventing damage to the substrate 3.

[0095] (Third embodiment) 10 is a schematic diagram of a peeling apparatus 30 according to this embodiment. The peeling apparatus 30 includes a container 31 for storing water 11, an ultrasonic generator 33 for applying ultrasonic waves to the water in the container 31, a mounting table 35 that is movable within the container 31 between a mounting position 35a where the substrate laminate 10 is mounted and an immersion position 35b where the substrate laminate 10 is immersed in water, and a liquid level adjustment mechanism 37 that maintains the water level in the container 31 at a predetermined level. The mounting table 35 is connected to a mounting shaft 35c. The mounting shaft 35c passes through a hole 31a in the bottom of the container 31 and extends to the outside of the container, and is connected to a drive source, such as an air cylinder (not shown), that enables movement of the mounting table 35. A seal ring 35d is attached around the hole 31a of the container 31, through which the mounting shaft 35c slides, to prevent water leakage from the container 31. The liquid level adjustment mechanism 37 can be configured, for example, with a float sensor and water inlet and outlet valves, and controls the outflow of water depending on the position at which the float sensor detects the water level.

[0096] When the peeling device 30 starts, the ultrasonic generator 33 begins applying ultrasonic waves to the water in the container 31. The liquid level adjustment mechanism 37 adjusts the liquid level in the container 31 so that the bonding surface between the transfer substrate 1 and the substrate 3 of the substrate assembly 10 is immersed in the water 11 when the mounting table 35 moves to the immersion position 35b. The mounting table 35 moves to the mounting position 35a by driving the air cylinder described above, and the substrate assembly 10 is placed on the mounting table 35. Next, the mounting table 35 moves to the immersion position 35b by driving the air cylinder, and the substrate assembly 10 is immersed in the water. The water 11 to which ultrasonic vibrations have been applied permeates the bonding surface between the transfer substrate 1 and the substrate 3, peeling the transfer substrate 1 from the substrate 3. The peeling device 30 in this embodiment is an apparatus suitable for use in the peeling process of the first embodiment.

[0097] (Fourth embodiment) FIG. 11 is a schematic diagram of a peeling apparatus 40 according to this embodiment. The peeling apparatus 40 according to this embodiment differs from the peeling apparatus 30 according to the third embodiment in that a pin 45e is provided on the mounting table 45 as the peeling member 19. Other components having similar functions and effects are given the same reference numerals, and their description will be omitted. In this embodiment, after the mounting table 45 places the substrate assembly 10 thereon and moves to the immersion position 35b, the pin 45e is caused to protrude upward from the mounting table 45 by an actuator (not shown) and presses the substrate 3 through the communication hole 17 provided in the transfer substrate 1. The peeling apparatus 40 according to this embodiment is an apparatus suitable for use in the second embodiment.

[0098] (Fifth embodiment) Fig. 12 is a schematic plan view of a peeling apparatus 50 according to this embodiment. Fig. 13 is an enlarged side view taken in the direction of arrow A in Fig. 12. The peeling apparatus 50 according to this embodiment includes a container 51 for storing water, an ultrasonic wave application stage 53 on which the substrate assembly 10 is placed when ultrasonic waves are applied to the substrate assembly 10, an ultrasonic generator 55 for applying ultrasonic waves to the substrate assembly 10, and a transfer robot 57 for transferring the substrate assembly 10 between the container 51 and the ultrasonic wave application stage 53. The container 51 includes a placement stage 35 that is movable within the container 51 between a placement position 35a on which the substrate assembly 10 is placed and an immersion position 35b on which the substrate assembly 10 is immersed in water, and a liquid level adjustment mechanism 37 that maintains the water level in the container 51 at a predetermined position.

[0099] 12, the transfer robot 57 in this embodiment is composed of a transfer robot 57a equipped with a rotating arm 56a for transferring the substrate assembly 10 from a carrier (not shown) to the container 51, and a transfer robot 57b equipped with a parallel movement arm 56b for transferring the substrate assembly 10 from the container 51 to the ultrasonic application table 53. The transfer robot 57a transfers the substrate assembly 10 by rotating the arm 56a about a rotation axis K as shown by arrows p and q, and is provided at its end with clamping members 59a that contact the outer periphery of the substrate assembly 10 at four points to clamp the substrate assembly 10. The transfer robot 57b transfers the substrate assembly 10 by parallel driving the arm 56b along a rail 58 as shown by arrow r, and is provided at its end with clamping members 59b that operate in the same manner as the transfer robot 57a.

[0100] As shown in Fig. 13, the container 51 according to this embodiment is the same as the peeling device 30 according to the third embodiment shown in Fig. 10, except that the ultrasonic generator 33 has been removed. Therefore, the same reference numerals are used to designate members that have the same functions and effects, and their description will be omitted.

[0101] The substrate assembly 10 transported to the container 51 by the transport robot 57a is placed on the mounting table 33 at the mounting position 35a. The mounting table 33 then moves to the immersion position 35b, where water 11 is allowed to penetrate into the bonded surfaces of the transport substrate 1 and the substrate 3 of the substrate assembly 10. After the substrate assembly 10 has been immersed in water at the immersion position 35b for a predetermined time, the substrate assembly 10 is transported from the container 51 to the ultrasonic wave application table 53 by cooperation between the mounting table 35 and the transport robot 57b. In the ultrasonic wave application table 53, an ultrasonic generator 55 disposed adjacent to the substrate assembly 10 is moved by an actuator (not shown) to a position where it comes into contact with the substrate assembly 10 and applies ultrasonic waves to the substrate assembly 10. The application of ultrasonic waves causes the transport substrate 1 and the substrate 3 to be separated. In this way, the water that has penetrated into the bonding surface of the substrate bonded body 10 weakens the bond between the transport substrate 1 and the substrate 3, and by further applying ultrasonic vibrations, the transport substrate 1 and the substrate 3 can be easily peeled apart.

[0102] (Sixth embodiment) 14 to 21 are diagrams showing channels formed at the bonding surface between the transfer substrate and the substrate according to this embodiment. In this embodiment, at least one channel is formed in the inorganic material layer to allow water to pass through the bonding surface. As shown in FIGS. 14 to 21, the channels 61 are formed as gaps in a pattern 63 of the inorganic material layer formed on the bonding surface of the transfer substrate 1 or the substrate 3 by ion beam sputtering or the like using a mask. In FIGS. 14 to 21, the pattern 63 of the inorganic material layer is indicated by diagonal hatching and is formed in the area not covered by the mask during ion beam sputtering. This embodiment can be applied to any of the above-mentioned embodiments. In this embodiment, when the substrate assembly is immersed in water, the channels 61 can promote contact of water at the bonding surface between the transfer substrate 1 and the substrate 3, making it easier to separate the transfer substrate 1 and the substrate 3.

[0103] (Seventh embodiment) 22 is a schematic plan view of a bonding apparatus 70 according to this embodiment. The bonding apparatus 70 includes a transfer substrate load lock chamber 71 for loading and unloading a transfer substrate, a substrate load lock chamber 72 for loading and unloading a substrate, a transfer chamber 73 in which a transfer robot is installed, a sputtering chamber 74 for forming an inorganic material layer on the transfer substrate or substrate directly or via a mask, a mask chamber 75 connected to the sputtering chamber and storing a mask for covering the transfer substrate or substrate, an inert gas treatment chamber 76 for exposing the transfer substrate or substrate to an inert gas atmosphere, an activation treatment chamber 77 for activating the transfer substrate or substrate with an ion beam, and a bonding chamber 78 for bonding the transfer substrate and substrate. The transfer substrate load lock chamber 71, the substrate load lock chamber 72, the sputtering chamber 74, the inert gas treatment chamber 76, the activation treatment chamber 77, and the bonding chamber 78 are each connected to the transfer chamber 73 by a gate valve 79 so that the transfer substrate or substrate can be transferred among them.

[0104] The transfer substrate and the substrate carried into the transfer substrate load lock chamber 71 and the substrate load lock chamber 72 undergo the necessary processing for bonding in the respective chambers, and are finally sent to the bonding chamber 78 where the bonding surfaces of the transfer substrate and the substrate are pressed against each other and bonded. The processing performed on the transfer substrate and the substrate is as follows: (1) Inorganic material layer formation (sputtering chamber 74) In the sputtering chamber 74, an inorganic material layer is formed by sputtering, for example, ion beam sputtering, on either or both of the transfer substrate and the surface of the substrate to be bonded. When forming the flow path shown in embodiment 6 on the bonding surface, a necessary mask is transferred from the adjacent mask chamber 75 to cover the transfer substrate and the surface of the substrate to be bonded.

[0105] (2) Surface activation before bonding (activation treatment chamber 77) In the activation treatment chamber 77, the transfer substrate and the surfaces of the substrate to be bonded are subjected to surface activation treatment using an ion beam. (3) Surface replacement treatment with inert gas (inert gas treatment chamber 76) In the inert gas treatment chamber 76, a surface substitution treatment is performed on the transfer substrate and the surfaces to be bonded of the substrate with an inert gas. Here, the inert gas may be, for example, nitrogen. (4) Bonding (bonding chamber 78) After selecting the appropriate process from (1) to (3), the transfer substrate and the substrate that have been processed are transferred to bonding chamber 78, where the transfer substrate and the substrate are bonded. After bonding is complete, the bonded substrate assembly is transferred by the transfer robot in transfer chamber 74 to transfer substrate load lock chamber 71 or substrate load lock chamber 72, and then taken out of the apparatus, completing the series of bonding steps.

[0106] Whether or not the above processes (1) to (3) are performed on the transfer substrate and the substrates up to bonding may be appropriately determined by a control device (not shown). In other words, the processes (1) to (3) are freely selected depending on the characteristics and state of the desired substrate bonded body. Each of the transfer substrate load lock chamber 71, substrate load lock chamber 72, sputtering chamber 74, inert gas treatment chamber 76, activation treatment chamber 77, and bonding chamber 78 is connected to transfer chamber 73 by gate valve 79, so that an appropriate process flow can be assembled by a transfer robot installed in transfer chamber 73.

[0107] The most distinctive feature of the peeling methods in the embodiments described above is that the bonding film can be adjusted. The process we are most interested in is when the transfer base is a silicon wafer and the substrate (interposer) is glass or a silicon wafer. In this case, the transfer base and interposer are temporarily bonded together, and then thinned using CMP. The distinctive feature of this process is that it is a technology that can create or adjust an inorganic bonding film that is strong enough to withstand the pressure of grinding, the water cleaning during grinding, and the subsequent semiconductor wafer stacking process. And to adjust these, (1) Inorganic membrane on one side (2) Inorganic film on both sides (3) Activation of only one side of the inorganic membrane (4) Both sides of the inorganic membrane are activated. There are two options, and either vacuum or nitrogen can be used for lamination. In addition, the bonding strength and peeling strength can be adjusted by forming the flow channel. The flow channel is also formed using a mask. Therefore, flow channels with various shapes can be formed.

[0108] In the embodiments described so far, separation has been explained by interposing water between the bonding surfaces of the substrate and the transport substrate. Here, the water interposed between the bonding surfaces may be anything that contains water. For example, it may be an alcohol such as ethanol, or an aqueous solution containing a certain chemical substance. Any fluid that functions similarly to water may be used as long as it is interposed between the bonding surfaces to promote separation. The fluid here is not limited to a liquid, but may also be a gas.

[0109] Having described the preferred embodiments of the present invention, it will be apparent that modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims. [Example]

[0110] Examples of the present invention are shown below, but the scope of the present invention should not be construed as being limited to these examples.

[0111] The tests in the examples were carried out according to the following procedure.

[0112] (1) Preparation of transfer substrate and device substrate As a combination of samples, alkali-free glass was prepared as a substrate for transportation, and a silicon wafer was prepared as a device substrate.

[0113] (2) Formation of inorganic layer As shown in Table 1 below, for each sample, an inorganic layer of Si (silicon) and AlO (aluminum oxide) was formed on the surface of a silicon wafer using ion beam sputtering. The number of scans was three, with 1.5 nm formed per scan, resulting in a 4.5 nm inorganic layer of Si (silicon) and AlO (aluminum oxide). For each sample, the presence or absence of a mask for forming the inorganic layer pattern 63 shown in FIG. 14 was selected.

[0114] (3) Room temperature bonding process The room temperature bonding process was carried out under the following conditions. (Room temperature bonding conditions) Pressing conditions: 5kN / 5min Pressing environment: N2 (nitrogen) environment

[0115] (5) Peeling The bonded sample was immersed in pure water and subjected to ultrasonic vibration.

[0116] (Results of peeling) As shown in Table 1, all of the masks peeled off within 10 minutes. This shows that the masks with flow channels formed on them peeled off quickly. [Table 1]

[0117] From the above results, it can be seen that the substrate can be easily peeled off by the peeling method according to the present invention. [Explanation of symbols]

[0118] 1 Carrier board 2 Inorganic material layer 3. Circuit Board 4 Electronic elements 11 water 13, 31, 51 containers 17 Flow hole 19 Peeling member 30, 40, 50 Peeling device 33, 55 Ultrasonic generator 35, 45 Mounting table 35a Placement position 35b Immersion position 37 Liquid level adjustment mechanism 53 Ultrasonic wave stamping stand 57, 57a, 57b Transport robot 61 Flow path 70 Bonding equipment 71 Transfer substrate load lock chamber 72 Substrate Load Lock Chamber 73 Transfer Chamber 74 Sputtering chamber 75 Mask Room 76 Inert gas treatment chamber 77 Activation Processing Chamber 78 Bonding Chamber 79 Gate Valve

Claims

1. A method for bonding and peeling a substrate having electronic elements formed on a surface thereof to a transfer substrate for transferring the substrate, comprising: bonding the bonding surfaces of the substrate and the transportation substrate via an inorganic material layer; separating the substrate and the transportation substrate by placing water between the bonding surfaces of the substrate and the transportation substrate; the transfer substrate is formed with at least one flow hole for allowing water to pass through the bonding surface; The peeling step includes pressing and peeling the substrate with a peeling member inserted into the through hole.

2. The bonding and peeling method according to claim 1 , wherein the water is subjected to ultrasonic vibrations.

3. The bonding / separating method according to claim 1 , further comprising the step of applying ultrasonic vibrations to the bonding surfaces after placing water between the bonding surfaces.

4. The bonding / peel-off method according to claim 1 , wherein the inorganic material layer has at least one flow path formed therein for allowing water to be present on the bonding surface.

5. 5. The bonding / debonding method according to claim 1, wherein the inorganic material layer contains any one of silicon, aluminum oxide, titanium oxide, copper, silicon nitride, aluminum, titanium, nickel, tin, and graphite, or any combination thereof.

6. The bonding / separating method according to claim 1 , wherein the substrate and the transfer substrate are any one of glass, silicon, a compound semiconductor, and a polymer film, or a combination thereof.

7. A method for manufacturing a substrate on which electronic elements are formed, comprising: forming an inorganic material layer on at least one of a surface of the substrate to be joined with a transportation substrate and a surface of the transportation substrate to be joined for transporting the substrate; pressing the substrate and the transfer substrate against each other to bond the substrate and the transfer substrate together via the inorganic material layer; separating the substrate and the transportation substrate by placing water between the bonding surfaces of the substrate and the transportation substrate; the transfer substrate is formed with at least one flow hole for allowing water to pass through the bonding surface; The peeling step includes pressing and peeling the substrate with a peeling member inserted into the through hole.

8. The method for manufacturing a substrate according to claim 7 , further comprising applying ultrasonic vibrations to the water.

9. The manufacturing method according to claim 7, further comprising applying ultrasonic vibrations to the bonding surfaces after placing water between the bonding surfaces.

10. The manufacturing method according to claim 7 , further comprising forming at least one flow path in the inorganic material layer for allowing water to be present at the joining surface.

11. The manufacturing method according to claim 7 , wherein the inorganic material layer contains any one or any combination of silicon, aluminum oxide, titanium oxide, copper, silicon nitride, aluminum, titanium, nickel, tin, and graphite.

12. The manufacturing method according to claim 7 , wherein the substrate and the transfer substrate are any one of glass, silicon, a compound semiconductor, and a polymer film, or a combination thereof.

13. The manufacturing method according to claim 7 , further comprising, prior to the bonding, activating the surface of the inorganic material layer by irradiating it with particles having a predetermined kinetic energy.

14. The manufacturing method according to claim 7 , wherein the bonding is performed in a vacuum atmosphere or a gas atmosphere containing an inert gas.

15. A thin substrate manufactured by the manufacturing method according to any one of claims 7 to 14.

16. a container for holding water; an ultrasonic wave application table on which the substrate bonded body is placed when ultrasonic waves are applied to the substrate bonded body; an ultrasonic generator that applies ultrasonic waves to the substrate bonded body; a transfer robot that transfers the substrate bonded body between the container and the ultrasonic wave application table, The container comprises: a mounting table that is movable within the container between a mounting position where the substrate assembly is mounted and an immersion position where the substrate assembly is immersed in water; and a liquid level adjustment mechanism that maintains the water level in the container at a predetermined position.

Images