Easily separated array substrate and preparation method thereof

Abstract

The invention discloses an easy-to-separate array substrate and a preparation method thereof, and the method comprises the steps: etching a sacrificial layer cavity in a substrate, and filling the sacrificial layer cavity with a sacrificial layer to obtain a first supporting substrate; preparing an array substrate on the first supporting substrate, wherein the array substrate is used for bearing a semiconductor device; and removing the sacrificial layer, and separating the array substrate from the substrate. According to the technical scheme provided by the invention, the orderliness and convenience of stripping the semiconductor device from the substrate can be improved.

Description

Technical Field

[0001] The present application belongs to the technical field of semiconductor device preparation, and in particular relates to an easily separable array substrate and a preparation method thereof. Background Art

[0002] In the traditional semiconductor manufacturing technology process, after various types of semiconductor devices are prepared on the substrate according to the established process, they form a fixed bond with the substrate, making it difficult to completely remove them from the substrate for independent use. Usually, in order to meet subsequent application requirements, the substrate needs to be thinned first, and then the substrate and the device are packaged as a whole. This process not only causes unnecessary waste in the use of substrate materials and subsequent packaging links, but the presence of the substrate and the thinning operation itself may also interfere with the performance of the device to a certain extent. For example, it may cause mechanical stress or microcracks at the interface between the substrate and the device, affecting its performance in actual applications. Based on this, how to improve the convenience of peeling semiconductor devices from the substrate is a technical problem that needs to be solved urgently. Summary of the Invention

[0003] The embodiments of the present application provide an easily separable array substrate and a method for preparing the same, thereby improving the orderliness and convenience of peeling a semiconductor device from a substrate.

[0004] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by practice of the present application.

[0005] According to a first aspect of an embodiment of the present application, a method for preparing an easily separable array substrate is provided, characterized in that the method includes: etching a sacrificial layer cavity on a substrate, and filling the sacrificial layer cavity with a sacrificial layer material to obtain a first supporting substrate; preparing an array substrate on the first supporting substrate, the array substrate being used to carry semiconductor devices; removing the sacrificial layer, and separating the array substrate from the substrate.

[0006] In some embodiments of the present application, based on the aforementioned scheme, a sacrificial layer cavity is etched on the substrate, and a sacrificial layer material is filled in the sacrificial layer cavity to obtain a first supporting substrate, including: etching a sacrificial layer cavity of a first preset specification on the substrate by a dry etching method; depositing a sacrificial layer material in the sacrificial layer cavity by a chemical vapor deposition method to obtain a sacrificial layer, and performing chemical mechanical planarization on the surface of the sacrificial layer to obtain a first supporting substrate.

[0007] In some embodiments of the present application, based on the aforementioned scheme, the preparation of the array substrate on the first supporting substrate includes: depositing a first preset thickness of substrate material on the surface of the first supporting substrate by physical vapor deposition to obtain a substrate layer; and etching a base film and a support tape on the base layer by photolithography, wherein the support tape and the base film constitute the array substrate.

[0008] In some embodiments of the present application, based on the aforementioned scheme, the method further includes: laying a sacrificial layer material on a substrate, and etching the laid sacrificial layer material into a sacrificial layer of a second preset specification by photolithography and etching to obtain a second supporting substrate; depositing a base material on the second supporting substrate to form a base layer, and etching a base film and a support tape on the base layer by photolithography and etching, wherein the support tape and the base film constitute an array substrate; removing the sacrificial layer, and separating the array substrate from the substrate.

[0009] In some embodiments of the present application, based on the aforementioned solution, the sacrificial layer is removed by dry etching or wet etching.

[0010] In some embodiments of the present application, based on the aforementioned solution, the sacrificial layer material is a material that is easy to remove and does not affect the substrate and array base when removed, and at least includes porous silicon, photoresist, metal material, insulating material and polymer.

[0011] In some embodiments of the present application, based on the aforementioned solution, the base material is a material having supporting, protecting, insulating or heat dissipating functions, including at least metal material, insulating material and thermal grease.

[0012] According to the second aspect of the embodiment of the present application, an easily separable array substrate is provided, characterized in that the array substrate includes: a sacrificial layer for temporarily supporting a base membrane and separating the base membrane from the substrate; a base membrane, the base membrane is located on the surface of the sacrificial layer and is used to carry semiconductor devices; and a support belt, the support belt is located around the base membrane and is connected to the base membrane, and is used to restrain and fix the base membrane.

[0013] In some embodiments of the present application, based on the aforementioned solution, the array substrate further comprises: a substrate for supporting the processing of the sacrificial layer, the base film, and the support tape, including at least silicon, GaN, GaAs, stainless steel, ceramic, printed circuit board, and flexible substrate.

[0014] In some embodiments of the present application, based on the aforementioned scheme, the array substrate is prepared by the method described in any one of the first aspects above.

[0015] Based on the technical solution proposed in this application, by pre-etching a cavity on the substrate and filling it with a sacrificial layer, when it is necessary to separate the semiconductor device, the array substrate and the substrate can be separated by removing the sacrificial layer. In this way, the array substrate can be easily separated from the substrate with less damage to the array substrate, and the array substrate after separation can be guaranteed to have good order, integrity and performance.

[0016] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, explaining the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0018] Figure 1 A flow chart showing a method for preparing an easily separable array substrate in one embodiment of the present application is shown;

[0019] Figure 2 shows a cross-sectional schematic diagram of a first supporting substrate in one embodiment of the present application;

[0020] Figure 3 shows a cross-sectional schematic diagram of the base layer in one embodiment of the present application;

[0021] Figure 4 A cross-sectional schematic diagram of a base film and a support tape in one embodiment of the present application is shown;

[0022] Figure 5 A schematic cross-sectional view of a semiconductor device on a first supporting substrate in one embodiment of the present application is shown;

[0023] Figure 6 A cross-sectional schematic diagram of removing the sacrificial layer of the first supporting substrate in one embodiment of the present application is shown;

[0024] Figure 7 shows a cross-sectional schematic diagram of a second supporting substrate in one embodiment of the present application;

[0025] Figure 8 A cross-sectional schematic diagram of depositing a base layer on a sacrificial layer in one embodiment of the present application is shown;

[0026] Figure 9 A cross-sectional schematic diagram of fabricating a semiconductor device on a second supporting substrate in one embodiment of the present application is shown;

[0027] Figure 10 A cross-sectional schematic diagram of removing a sacrificial layer from a second supporting substrate in one embodiment of the present application is shown;

[0028] Figure 11 A schematic diagram of an array substrate in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0031] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0032] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0033] It should also be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that shown or described.

[0034] In the traditional semiconductor preparation technology process, after various types of semiconductor devices are prepared on the substrate according to the established process, they form a fixed bond with the substrate, and it is difficult to remove them completely from the substrate for independent use. Usually, in order to meet subsequent application requirements, the substrate needs to be thinned first, and then the substrate and the device are packaged as a whole. This process will not only cause unnecessary waste in the use of substrate materials and subsequent packaging links, but the existence of the substrate and the thinning operation itself may also interfere with the performance of the device to a certain extent. For example, it may cause mechanical stress or microcracks at the interface between the substrate and the device, affecting its performance in actual applications. Based on this, the present application proposes a method for preparing an easily separable array substrate to improve the convenience of peeling semiconductor devices from the substrate.

[0035] Next, we will combine Figure 1 The method for preparing the easily separable array substrate proposed in this application is described in detail.

[0036] See also Figure 1 , shows a flow chart of a method for preparing an easily separable array substrate in one embodiment of the present application, such as Figure 1 As shown, the method may at least include the following steps 110 to 130:

[0037] Step 110 , etching a sacrificial layer cavity on the substrate, and filling the sacrificial layer cavity with a sacrificial layer material to obtain a first supporting substrate.

[0038] Step 120: preparing an array substrate on the first supporting substrate, wherein the array substrate is used to carry semiconductor devices.

[0039] Step 130: remove the sacrificial layer and separate the array base from the substrate.

[0040] In the present application, the sacrificial layer material is a material that is easy to remove and does not affect the substrate and array base when removed. Specifically, it can be porous silicon, photoresist, metal material (such as aluminum or tungsten), insulating material (such as SiO2 or Si3N4), polymer (such as PI), etc., which can be selected according to the process characteristics of the semiconductor device. This application does not make any specific restrictions on this.

[0041] In the present application, the sacrificial layer can be removed by dry etching or wet etching, and the specific method can be determined according to the type of sacrificial layer material, and the present application does not make any specific limitation on this.

[0042] In the present application, a cavity of a specific shape is etched on the surface of the substrate through an etching process, and a sacrificial layer material that can be removed subsequently is filled to form a temporary support structure (i.e., a sacrificial layer). The sacrificial layer provides mechanical support for the subsequent preparation of the array substrate to ensure that the array substrate and the substrate can ultimately be separated by removing the sacrificial layer. In this way, the semiconductor device prepared on the array substrate can be easily separated from the substrate, avoiding waste and damage to the semiconductor device.

[0043] In the present application, by pre-etching a cavity on the substrate and filling it with a sacrificial layer, when it is necessary to separate the semiconductor device, the array base and the substrate can be separated by removing the sacrificial layer. In this way, the array base can be easily separated from the substrate with less damage to the array base, and the array base after separation can be guaranteed to have good order, integrity and performance.

[0044] In the above step 110, the sacrificial layer cavity is etched on the substrate, and the sacrificial layer cavity is filled with a sacrificial layer material to obtain a first supporting substrate. Specifically, the steps 111 to 112 are as follows:

[0045] Step 111 : etching a sacrificial layer cavity of a first preset size on the substrate by dry etching.

[0046] Step 112 , depositing a sacrificial layer material in the sacrificial layer cavity by chemical vapor deposition to obtain a sacrificial layer, and performing chemical mechanical planarization on the surface of the sacrificial layer to obtain a first supporting substrate.

[0047] In the present application, the first preset specification can specifically be a cavity with a depth of 3 μm, an opening of 50×100 μm, and an angle of 100°, or other specifications, which can be determined based on the process requirements for semiconductor device preparation. This application does not make any specific limitations on this.

[0048] In this application, a sacrificial layer cavity is etched out according to the first preset specification through dry etching technology, which has the advantages of fast etching rate, good selectivity, and clear etching contour. It can ensure that the size and shape of the sacrificial layer cavity meet the design requirements and provide a good foundation for the subsequent filling of the sacrificial layer.

[0049] In this application, please refer to Figure 2 As shown, a cross-sectional schematic diagram of the first supporting substrate in one embodiment of the present application is shown. Figure 2As shown, the sacrificial layer 201 and the substrate 202 together constitute the first supporting substrate; in the etched sacrificial layer cavity, the sacrificial layer material is deposited by chemical vapor deposition (CVD) technology, which has the advantages of fast deposition rate, high film quality, controllable composition and thickness, etc., and can ensure that the sacrificial layer material is evenly and densely filled in the sacrificial layer cavity to form a stable sacrificial layer structure, thereby ensuring the stability of subsequent array substrate preparation.

[0050] In this application, after the deposition of the sacrificial layer is completed, the surface of the sacrificial layer is subjected to chemical mechanical planarization (CMP) treatment. Combined with chemical etching and mechanical grinding, the uneven parts of the surface of the sacrificial layer are removed through the joint action of polishing liquid and polishing pad, which can significantly improve the flatness of the surface of the sacrificial layer, reduce defects and adverse effects in subsequent processes, and provide good surface conditions for the preparation of the array substrate.

[0051] In the above step 120, the array substrate is prepared on the first supporting substrate, which can be specifically performed according to the following steps 121 to 122:

[0052] Step 121 : depositing a base material with a first preset thickness on the surface of the sacrificial layer by physical vapor deposition to obtain a base layer.

[0053] Step 122: etching a base film and a support tape on the base layer by photolithography and etching, wherein the support tape and the base film constitute an array substrate.

[0054] In the present application, the first preset thickness may specifically be 0.3 μm. Depending on the actual process requirements of the semiconductor device, it may also be other thicknesses, which is not specifically limited in the present application.

[0055] In this application, please refer to Figure 3 and Figure 4 As shown, Figure 3 FIG. 1 shows a cross-sectional schematic diagram of the base layer in one embodiment of the present application. Figure 4 A cross-sectional schematic diagram of a base film and a support tape in one embodiment of the present application is shown. Figure 4 As shown, the base layer 203 can be etched by photolithography to obtain a base film 204 and a support tape 205. The base film 204 is located on the surface of the sacrificial layer, and the support tape 205 can be located on the surface of the substrate. The support tape 205 and the base film 204 are connected to each other.

[0056] In the present application, a layer of base material is deposited on the surface of the first supporting substrate (i.e., the substrate including the sacrificial layer) by physical vapor deposition (PVD). The base material is deposited onto the surface of the first supporting substrate through physical processes (such as evaporation, sputtering, etc.) to form a uniform and dense base layer. The thickness and composition of the deposited layer can be accurately controlled to ensure the uniformity and density of the base layer, providing a good foundation for subsequent photolithography etching of the base film and support tape.

[0057] In the present application, after the deposition of the base layer is completed, the photolithography technology is used to determine the specific shape and position of the base film and the support belt. Specifically, a specific pattern can be formed on the base layer through steps such as exposure and development, and then the pattern is transferred to the base layer through an etching process to form the base film and the support belt. In this way, the array substrate is etched by photolithography technology with high precision and high resolution, and can accurately etch the required base film and support belt structure, thereby ensuring the reliability of the array substrate.

[0058] For further information, please refer to Figure 5 and Figure 6 , Figure 5 FIG2 shows a cross-sectional schematic diagram of a semiconductor device on a first supporting substrate in one embodiment of the present application. Figure 6 FIG. 1 shows a cross-sectional schematic diagram of removing the sacrificial layer of the first supporting substrate in one embodiment of the present application. Figure 5 and Figure 6 As shown, the semiconductor device 206 can be prepared above the base film 204. After the preparation is completed, the sacrificial layer 201 is removed to form a cavity 207 between the base film 204 and the substrate 202, and the base film 204 is separated from the substrate 202. By disconnecting the connection between the base film 204 and the support tape 205, the base film 204 and the semiconductor device 206 can be removed in an orderly manner, thereby improving the convenience of peeling the semiconductor device from the substrate.

[0059] In the preparation method proposed in this application, the array substrate can also be prepared according to the following steps 210 to 230:

[0060] Step 210 : laying a sacrificial layer material on the substrate, and etching the laid sacrificial layer material into a sacrificial layer of a second preset specification by photolithography and etching to obtain a second supporting substrate.

[0061] In step 220 , a base material is deposited on the second supporting substrate to form a base layer, and a base film and a supporting tape are etched on the base layer by photolithography and etching. The supporting tape and the base film constitute an array substrate.

[0062] Step 230: remove the sacrificial layer and separate the array base from the substrate.

[0063] In this application, the base material is a material with supporting, protecting, insulating or heat dissipating functions, including but not limited to metal materials (such as copper), insulating materials (such as SiO2 or Si3N4), thermal grease, etc. The specific material can be selected according to the process characteristics of the semiconductor device.

[0064] In this application, please refer to Figure 7 As shown, a cross-sectional schematic diagram of a second supporting substrate in an embodiment of the present application is shown. The second supporting substrate may include at least a substrate 202 and a sacrificial layer 201. The first supporting substrate and the second supporting substrate are supporting substrates of different structures obtained by different preparation methods in different embodiments.

[0065] In this application, please refer to Figure 8 FIG. 1 shows a cross-sectional schematic diagram of depositing a base layer on a sacrificial layer in one embodiment of the present application. Figure 8 As shown, a base material is deposited on the surface of the substrate 202 and the sacrificial layer 201 to form a base layer, and then a base film and a support tape are etched on the base layer 203 by photolithography. Specifically, a base film 204 is etched on the base layer 203 above the sacrificial layer 201, and a support tape 205 is etched on the base layer 203 above the substrate 202, thereby obtaining an array substrate consisting of a base film and a support tape.

[0066] In this application, please refer to Figure 9 and Figure 10 , Figure 9 FIG2 shows a cross-sectional schematic diagram of preparing a semiconductor device on a second supporting substrate in one embodiment of the present application. Figure 10 A cross-sectional schematic diagram illustrating the removal of a sacrificial layer from a second supporting substrate in one embodiment of the present application is shown. Depositing the base layer and then etching the resulting base film 204 provides a stable platform for fabricating a supporting semiconductor device 206. The support tape 205 provides sufficient mechanical support for the base film 204, preventing the base film 204 and the supported semiconductor device 206 from losing support and falling after the sacrificial layer 201 is removed to form the cavity 207. This prevents deformation or damage during subsequent processing and use.

[0067] Next, please refer to Figure 11 , shows a schematic diagram of an array substrate in one embodiment of the present application, such as Figure 11 As shown, the prepared base film 204 and the support tape 205 are distributed in sequence on the substrate 202. After removing the sacrificial layer 201, the semiconductor device 206 and the base film 204 can be separated from the substrate 202. After cutting off the connection between the support tape 205 and the base film 204, the semiconductor device 206 can be removed, thereby improving the convenience of separating the semiconductor device from the substrate.

[0068] Based on the technical solution proposed in this application, by pre-etching a cavity on the substrate and filling it with a sacrificial layer, when it is necessary to separate the semiconductor device, the array substrate and the substrate can be separated by removing the sacrificial layer. In this way, the array substrate can be easily separated from the substrate with less damage to the array substrate, and the array substrate after separation can be guaranteed to have good integrity and performance.

[0069] Based on the same inventive concept, the present application also proposes an easily separable array substrate, which can be prepared by the above-mentioned method for preparing an easily separable array substrate.

[0070] For details, please refer to Figure 11 As shown, the array substrate may include a sacrificial layer 201, a base film 204 and a support tape 205, wherein the sacrificial layer 201 may be used to temporarily support the base film 204 and separate the base film 204 from the substrate 202; the base film 204 is located on the surface of the sacrificial layer 201 and may be used to carry the semiconductor device 206; the support tape 205 is located around the base film 204 and is connected to the base film 204 and may be used to support the base film 204; in addition, the array substrate may further include a supporting substrate, which may be used to carry the processing process of the sacrificial layer 201, the base film 204 and the support tape 205.

[0071] Next, this application will illustrate the technical solutions proposed in this application in conjunction with some specific embodiments.

[0072] Example 1: First, a cavity with a depth of 3 μm, an opening of 50×100 μm, and an angle of 100° is dry-etched on a silicon substrate, and then a sacrificial layer of phosphosilicate glass (PSG) is deposited by chemical vapor deposition (CVD) and then chemical mechanical planarization (CMP) is performed to obtain a first supporting substrate with a sacrificial layer.

[0073] Secondly, a 0.3 μm array base metal gold (Au) is deposited on the first supporting substrate using physical vapor deposition (PVD), and a base film and a supporting tape are produced by photolithography patterning.

[0074] Then, a semiconductor device can be prepared on the base film. Finally, the sacrificial layer of phosphosilicate glass (PSG) is removed by wet etching, and the base film can be separated from the substrate. The connection between the supporting tape and the base film is then disconnected, and the semiconductor device can be peeled off and used independently.

[0075] Example 2: A sacrificial layer material PSG with a thickness of 0.3 μm is deposited on a silicon substrate, which is then patterned by photolithography and dry-etched to obtain a sacrificial layer, thereby obtaining a second supporting substrate.

[0076] Secondly, a 0.2 μm copper (Cu) base material is deposited on the second supporting substrate, and a base film and a supporting tape are formed by dry etching based on photolithography patterning.

[0077] Then, a semiconductor device can be prepared on the base film. Finally, the sacrificial layer of phosphosilicate glass (PSG) is removed by wet etching, and the base film can be separated from the substrate. The connection between the supporting tape and the base film is then disconnected, and the semiconductor device can be peeled off and used independently.

[0078] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of the claims of the present application.

Claims

1. A method for preparing an easily separable array substrate, characterized in that: The method comprises: Etching a sacrificial layer cavity on the substrate and filling the sacrificial layer cavity with a sacrificial layer material to obtain a first supporting substrate; preparing an array substrate on the first supporting substrate, wherein the array substrate is used to carry semiconductor devices; The sacrificial layer is removed, and the array base is separated from the substrate.

2. The method according to claim 1, characterized in that The step of etching a sacrificial layer cavity on the substrate and filling the sacrificial layer cavity with a sacrificial layer material to obtain a first supporting substrate comprises: etching a sacrificial layer cavity of a first preset specification on the substrate by dry etching; A sacrificial layer material is deposited in the sacrificial layer cavity by chemical vapor deposition to obtain a sacrificial layer, and a surface of the sacrificial layer is subjected to chemical mechanical planarization to obtain a first supporting substrate.

3. The method according to claim 1, characterized in that The step of preparing an array substrate on the first supporting substrate comprises: Depositing a base material of a first preset thickness on the surface of the first supporting substrate by physical vapor deposition to obtain a base layer; A base film and a support tape are etched on the base layer by photolithography and etching, and the support tape and the base film constitute an array base.

4. The method according to claim 1, wherein The method further comprises: Laying a sacrificial layer material on the substrate, and etching the laid sacrificial layer material into a sacrificial layer of a second preset specification by photolithography and etching to obtain a second supporting substrate; Depositing a base material on the second supporting substrate to form a base layer, and etching a base film and a supporting tape on the base layer by photolithography, wherein the supporting tape and the base film constitute an array base; The sacrificial layer is removed, and the array base is separated from the substrate.

5. The method according to any one of claims 1 to 4, characterized in that The sacrificial layer is removed by dry etching or wet etching.

6. The method according to any one of claims 1 to 4, characterized in that The sacrificial layer material is a material that is easy to remove and does not affect the substrate and the array base when removed, and at least includes porous silicon, photoresist, metal material, insulating material and polymer.

7. The method according to any one of claims 3 to 4, characterized in that The base material is a material with supporting, protecting, insulating or heat dissipating functions, and at least includes metal material, insulating material and thermal conductive silicone grease.

8. An easily separable array substrate, characterized in that: The array substrate comprises: a sacrificial layer, used for temporarily supporting the base film and separating the base film from the substrate; a base film, the base film being located on a surface of the sacrificial layer and being used to support a semiconductor device; A support belt is located around the base membrane and connected to the base membrane to restrain and fix the base membrane.

9. The array substrate according to claim 8, characterized in that: The array substrate further comprises: The substrate is used for the processing of supporting the sacrificial layer, the base film and the support tape, and includes at least silicon, GaN, GaAs, stainless steel plate, ceramic, printed circuit board and flexible substrate.

10. The array substrate according to claim 8 or 9, characterized in that: The array substrate is prepared by the method according to any one of claims 1 to 7.

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