Method of Using Temporary Adhesive

Abstract

To provide a structure and a usage method of a temporary adhesive material capable of temporarily adhering a wafer and a support with sufficient strength, easily peeling the wafer from the support, and repeatedly performing temporary adhesion and peeling.SOLUTION: In a method of temporarily adhering a wafer 10 having a first main surface 11 including a circuit 13 and a second main surface 12 to be processed opposite to the first main surface to a support 3 via a temporary adhesive layer 2, temporary adhesion between the first main surface of the wafer and the support is performed via a temporary adhesion layer including a dry adhesive fiber structure 21 having a plurality of columnar structures 22. This makes it possible to temporarily adhere the wafer and the support with sufficient strength and to easily peel the wafer from the support, and repeatedly perform the temporary adhesion and peeling.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a temporary bonding method, a device wafer processing method, a laminate for temporary bonding, and a laminate for device wafer processing.

Background Art

[0002] Three-dimensional semiconductor packaging has become essential for achieving higher density and larger capacity. The three-dimensional packaging technology is a semiconductor manufacturing technology in which a single semiconductor chip is thinned and then stacked in multiple layers while being connected by through-silicon vias (TSVs) or the like. To achieve this, it is necessary to thin the wafer on which the semiconductor circuit is formed by grinding the non-circuit forming surface (also referred to as the "back surface"), and further perform an electrode forming process including TSVs on the back surface. Conventionally, in the back surface grinding process of a silicon substrate, a protective tape is attached to the opposite side of the grinding surface to prevent wafer breakage during grinding. However, this tape uses an organic resin film as a support substrate, and although it has flexibility, its strength and heat resistance are insufficient, and it is not suitable for performing the TSV forming process or the wiring layer forming process on the back surface.

[0003] Therefore, a system has been proposed in which a semiconductor wafer is bonded to a support such as silicon or glass via an adhesive layer, which can sufficiently withstand the processes of back surface grinding, TSV formation, and back surface electrode formation. At this time, the adhesive layer when bonding the wafer to the support is important. This adhesive layer needs to be able to firmly bond the wafer to the support and have sufficient durability to withstand subsequent processes, and further, it is necessary to be able to simply peel the thin wafer from the support at the end. Thus, since it is peeled at the end, in this specification, this adhesive layer will be referred to as a temporary bonding layer.

[0004] As known prior arts of temporary adhesive layers and their peeling methods, there are a technique of irradiating a high-intensity light on an adhesive containing a light-absorbing substance to decompose the adhesive layer and peeling the adhesive layer from a support (Patent Document 1), and a technique of using a heat-melting hydrocarbon-based compound as an adhesive and performing bonding and peeling in a heat-melted state (Patent Document 2). The former technique is a technique of easily peeling a thin wafer from a support by ablating a laser absorption layer with a strong light from a laser oscillator, and it is a technique that hardly applies stress to the thinned wafer during peeling. The latter technique is a technique of thermally decomposing an adhesive by heating a substrate, and it is a very excellent temporary bonding technique when the process temperature for TSV formation and wiring formation performed after bonding the support is in a range where the adhesive does not cause thermal decomposition (about 200°C or lower).

[0005] In addition, a technique of using a silicone adhesive for a temporary adhesive layer has been proposed (Patent Document 3). This is a method of bonding a wafer to a support using an addition-curing type silicone adhesive, and separating the wafer from the support by immersing it in a chemical that dissolves or decomposes the silicone resin during peeling.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Non-Patent Documents

[0007]

Non-Patent Document 1

[0008] The materials used in existing temporary adhesion technologies basically have the function of bonding (adhering) a wafer to be thinned and a support, and moreover, they are characterized in the function of separating the thinned wafer and the support after processing. In the reference patent documents, laser ablation, thermal decomposition, and dissolution in a solvent are utilized. However, the temporary adhesion layer in the technologies described in these patent documents does not exhibit the function of bonding again after being used for bonding once and then peeled off. Therefore, the material that was the temporary adhesion layer generally disappears by being washed away after peeling. Therefore, it is necessary to form a new temporary adhesion layer for a new bonding. That is, the temporary adhesion layer in the conventional temporary adhesion technology could not be used repeatedly.

[0009] Furthermore, a dedicated device for performing laser ablation in Patent Document 1 is very expensive.

[0010] The present invention has been made in view of the above problems, and provides a temporary adhesion method capable of performing sufficient-strength temporary adhesion between a wafer and a support and easy peeling of the wafer from the support, and capable of repeatedly performing temporary adhesion and peeling, a device wafer processing method for processing a wafer by temporarily adhering the wafer and the support by this temporary adhesion method, a temporary adhesion laminate capable of performing sufficient-strength temporary adhesion between a wafer and a support and easy peeling of the wafer from the support, and capable of repeatedly performing temporary adhesion and peeling, and a device wafer processing laminate including this temporary adhesion laminate. [Means for Solving the Problems]

[0011] In order to achieve the above object, the present invention provides a method for temporarily bonding a wafer having a first main surface including a circuit and a second main surface to be processed on the opposite side of the first main surface to a support via a temporary bonding layer, wherein the temporary bonding is performed via a temporary bonding layer including a dry adhesive fiber structure having a plurality of columnar structures between the first main surface of the wafer and the support.

[0012] According to the temporary bonding method of the present invention, since the temporary bonding is performed via a temporary bonding layer including a dry adhesive fiber structure having a plurality of columnar structures, it is possible to prevent the wafer from separating from the support during processing such as thinning, electrode formation, metal wiring formation, and protective film formation. On the other hand, after the above processing, the wafer can be easily peeled off from the support without using expensive machinery or the like. Further, the dry adhesive fiber structure having a plurality of columnar structures can be reused for further temporary bonding after releasing the temporary bonding between the wafer and the support. That is, according to the temporary bonding method of the present invention, it is possible to perform temporary bonding with sufficient strength between the wafer and the support and easy peeling of the wafer from the support, and the temporary bonding and peeling can be repeated. Therefore, according to the temporary bonding method of the present invention, for example, a thin device wafer can be manufactured with high productivity and low cost.

[0013] As the dry adhesive fiber structure, it is preferable to use one in which the plurality of columnar structures are formed of a thermosetting resin.

[0014] A dry adhesive fiber structure in which a plurality of columnar structures are formed of a thermosetting resin can exhibit excellent resistance to vacuum processes and thermal processes. Therefore, by using such a dry adhesive fiber structure, the productivity and cost performance of the thin device wafer can be further improved.

[0015] As the dry adhesive fiber structure, it is preferable to use one in which the plurality of columnar structures are formed of a silicone-modified polyimide.

[0016] Such a dry adhesive fiber structure can exhibit excellent heat resistance and excellent flexibility in a plurality of columnar structures. Therefore, by using such a dry adhesive fiber structure, the productivity of thin device wafers can be further improved.

[0017] Also provided is a device wafer processing method, which temporarily bonds the first main surface of the wafer and the support by the temporary bonding method of the present invention, and processes the second main surface of the temporarily bonded wafer.

[0018] In the device wafer processing method of the present invention, the wafer and the support are temporarily bonded by the temporary bonding method of the present invention, and the second main surface of the wafer temporarily bonded in this way is processed. Therefore, thin device wafers can be manufactured with high productivity and low cost.

[0019] After processing the second main surface of the wafer, the temporary bonding by the temporary bonding layer is released, and then the temporary bonding layer can be repeatedly used in other temporary bondings.

[0020] The temporary bonding method of the present invention and the temporary bonding layer including the dry adhesive fiber structure used in the processing method of the device wafer of the present invention can be repeatedly used in temporary bonding and peeling.

[0021] After processing the second main surface of the wafer, the temporary bonding by the temporary bonding layer is released, and then another substrate different from the wafer can be temporarily bonded to the support through the temporary bonding layer.

[0022] In the device wafer processing method of the present invention, after processing one wafer, the temporary bonding layer can be repeatedly used to temporarily bond another substrate different from this wafer to the support.

[0023] Further, the present invention provides a temporary bonding laminate used for temporarily bonding a wafer to a support via a temporary bonding layer, the temporary bonding laminate including the support and the temporary bonding layer formed on the support, wherein the temporary bonding layer includes a dry adhesive fiber structure having a plurality of columnar structures.

[0024] In the temporary bonding laminate of the present invention, since the temporary bonding layer includes a dry adhesive fiber structure having a plurality of columnar structures, it is possible to prevent the wafer from separating from the support during processing such as thinning, electrode formation, metal wiring formation, and protective film formation. On the other hand, after the above processing, the wafer can be easily peeled off from the support without using expensive machinery or the like. Further, the dry adhesive fiber structure having a plurality of columnar structures can be reused for further temporary bonding after releasing the temporary bonding between the wafer and the support. That is, by using the temporary bonding laminate of the present invention, sufficient strength temporary bonding between the wafer and the support and easy peeling of the wafer from the support can be achieved, and temporary bonding and peeling can be repeated. Therefore, by using the temporary bonding laminate of the present invention, for example, a thin device wafer can be manufactured with high productivity and low cost.

[0025] Preferably, the plurality of columnar structures are formed of a thermosetting resin.

[0026] The columnar structure formed of a thermosetting resin can exhibit excellent resistance to vacuum processes and thermal processes. Therefore, by using a temporary bonding laminate including such columnar structures, the productivity and cost performance of thin device wafers can be further improved.

[0027] Examples of the plurality of columnar structures include silicone resins, polyimide resins, epoxy resins, acrylic resins, polyesters, polyamide resins, phenolic resins, fluorine resins, polyurethanes, polycarbonates, polystyrenes, rubbers such as SBR and NBR. In order to exhibit heat resistance and flexibility, it is preferably formed of a silicone-modified polyimide.

[0028] Such a columnar structure can exhibit excellent heat resistance and excellent flexibility. Therefore, by using the temporary adhesive laminate including such a columnar structure, the productivity of the thin device wafer can be further improved.

[0029] It is preferable that it further includes a guard ring surrounding the dry adhesive fiber structure formed on the support.

[0030] If it includes such a guard ring, for example, even when the second main surface of the wafer is subjected to a wet process, it is possible to prevent the processing liquid from entering the first main surface side of the wafer.

[0031] Further, in the present invention, there is provided a laminate for device wafer processing, including the temporary adhesive laminate of the present invention and a wafer having a first main surface including a circuit and a second main surface to be processed on the side opposite to the first main surface, wherein the first main surface is temporarily adhered to the support via the temporary adhesive layer on the support.

[0032] In the laminate for device wafer processing of the present invention, since the temporary adhesive layer includes a dry adhesive fiber structure having a plurality of columnar structures, it is possible to prevent the wafer from separating from the support during the processing of the second main surface of the wafer, and after the processing, the wafer can be easily peeled off from the support without using an expensive device. Further, after the processing, the temporary adhesive layer can be repeatedly used for other temporary adhesions. Therefore, by using the laminate for device wafer processing of the present invention, for example, a thin device wafer can be manufactured with high productivity and low cost.

Effects of the Invention

[0033] As described above, according to the temporary adhesive method of the present invention, it is possible to perform sufficient strength temporary adhesion between the wafer and the support and easy peeling of the wafer from the support, and the temporary adhesion and peeling can be repeated. Therefore, according to the temporary adhesive method of the present invention, a thin device wafer can be manufactured with high productivity and low cost.

[0034] In addition, according to the device wafer processing method of the present invention, thin device wafers can be manufactured with high productivity and low cost.

[0035] Furthermore, according to the temporary bonding laminate of the present invention, sufficient strength temporary bonding between the wafer and the support and easy peeling of the wafer from the support can be achieved, and temporary bonding and peeling can be repeated. Therefore, according to the temporary bonding laminate of the present invention, thin device wafers can be manufactured with high productivity and low cost.

[0036] And according to the laminate for device wafer processing of the present invention, thin device wafers can be manufactured with high productivity, and its utility value is extremely high.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0038] As described above, there has been a demand for the development of a temporary bonding method capable of achieving sufficient strength temporary bonding between the wafer and the support and easy peeling of the wafer from the support, and capable of repeating temporary bonding and peeling.

[0039] As a result of intensive studies on the above problems, the present inventors have found that by temporarily bonding the first main surface of a wafer, which is opposite to the second main surface to be processed, and a support through a temporary bonding layer including a dry adhesive fiber structure having a plurality of columnar structures, it is possible to perform temporary bonding with sufficient strength between the wafer and the support and easily peel the wafer from the support, and it is possible to repeat such temporary bonding and peeling, thus completing the present invention.

[0040] That is, the present invention is a method for temporarily bonding a wafer having a first main surface including a circuit and a second main surface to be processed, which is opposite to the first main surface, to a support through a temporary bonding layer, the method being characterized by performing temporary bonding between the first main surface of the wafer and the support through a temporary bonding layer including a dry adhesive fiber structure having a plurality of columnar structures.

[0041] Further, the present invention is a device wafer processing method, characterized by performing temporary bonding between the first main surface of the wafer and the support by the above-described temporary bonding method of the present invention, and processing the second main surface of the temporarily bonded wafer.

[0042] Furthermore, the present invention is a laminated body for temporary bonding used for temporarily bonding a wafer to a support through a temporary bonding layer, the laminated body including the support and the temporary bonding layer formed on the support, the temporary bonding layer including a dry adhesive fiber structure having a plurality of columnar structures.

[0043] And the present invention is a laminated body for device wafer processing, characterized by including the above-described laminated body for temporary bonding of the present invention and a wafer having a first main surface including a circuit and a second main surface to be processed, which is opposite to the first main surface, the first main surface being temporarily bonded to the support through the temporary bonding layer on the support.

[0044] For example, Patent Document 4 and Non-Patent Document 1 disclose a dry adhesive fiber structure. Also, for example, Patent Document 5 and Non-Patent Document 2 disclose a method for manufacturing a dry adhesive fiber structure. However, these documents do not mention anything about applying a dry adhesive fiber structure to temporary adhesion in a device wafer manufacturing process.

[0045] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0046] [Laminated body for temporary adhesion] The laminated body for temporary adhesion of the present invention is a laminated body for temporary adhesion used to temporarily adhere a wafer to a support via a temporary adhesion layer, and includes the support and the temporary adhesion layer formed on the support, and the temporary adhesion layer is characterized by including a dry adhesive fiber structure having a plurality of columnar structures.

[0047] The temporary adhesion layer including a dry adhesive fiber structure having a plurality of columnar structures can perform temporary adhesion between the wafer and the support by the tip of the columnar structure contacting the surface of the wafer. Although not bound by theory, it is presumed that when the tip of the columnar structure contacts the surface of the wafer, an intermolecular force is generated between the tips of the plurality of columnar structures and the surface of the wafer, and the temporary adhesion is performed by this intermolecular force.

[0048] Such temporary adhesion can provide a temporary adhesion with sufficient strength to prevent the wafer from separating from the support during processing of the wafer, such as thinning, electrode formation, metal wiring formation, and protective film formation.

[0049] On the one hand, after processing, this temporary adhesion enables the wafer to be easily peeled from the support without using expensive equipment. Specific peeling methods include, for example, a method of horizontally fixing one of the wafer or the support and lifting the other at a certain angle from the horizontal direction, a method of attaching a protective film to the ground surface of the ground wafer and peeling the wafer and the protective film from the wafer processed body by a peeling method, and a method of lifting and peeling a part of the wafer with tweezers. The present invention is applicable to any of these peeling methods. Of course, it is not limited to the above methods.

[0050] In addition, the temporary adhesion layer including the dry adhesive fiber structure having a plurality of columnar structures can be reused in other temporary adhesions even after the temporary adhesion is released. This is presumably because the temporary adhesion by the dry adhesive fiber structure utilizes intermolecular forces, and even if peeled once, if the tips of the plurality of columnar structures are brought into contact with the temporary adhesion target, the intermolecular forces are manifested again and further temporary adhesion can be performed.

[0051] Moreover, the temporary adhesion layer of the temporary adhesion laminate of the present invention can strongly adhere even if the temporary adhesion target is not necessarily flat. Since the first main surface to which the temporary adhesion layer temporarily adheres includes a circuit, it is usually not flat. The temporary adhesion layer of the temporary adhesion laminate of the present invention can strongly adhere to the first main surface including the circuit.

[0052] In addition, since the temporary adhesion by the temporary adhesion layer of the temporary adhesion laminate of the present invention is temporary adhesion based on intermolecular forces, it does not require an additional heat curing process as in the case of using an adhesive.

[0053] And since the temporary adhesion by the temporary adhesion layer of the temporary adhesion laminate of the present invention is temporary adhesion based on intermolecular forces, washing during repeated use is not necessarily required. That is, according to the present invention, there is no need for washing required by the conventional method, and a temporary adhesion process capable of shortening the time of the semiconductor device manufacturing process and reducing the washing cost can be provided.

[0054] Thus, by using the laminate for temporary bonding of the present invention, sufficient strength temporary bonding between the wafer and the support and easy peeling of the wafer from the support can be achieved, and temporary bonding and peeling can be repeated. Therefore, by using the laminate for temporary bonding of the present invention, for example, thin device wafers can be manufactured with high productivity and low cost.

[0055] Next, with reference to FIGS. 1 to 3, the laminate for temporary bonding of the present invention will be described more specifically.

[0056] FIG. 1 is a schematic partial cross-sectional view showing an example of the laminate for temporary bonding of the present invention. The laminate for temporary bonding 20 shown in FIG. 1 includes a support 3 and a temporary bonding layer 2 formed on the support 3. The temporary bonding layer 2 includes a dry adhesive fiber structure 21 having a plurality of fine columnar structures 22.

[0057] The material of the support 3 is not particularly limited, and for example, silicon, glass, quartz, etc. can be used. That is, as the support 3, for example, substrates such as silicon wafers, glass plates, and quartz wafers can be used without any restrictions. In the present invention, since it is not necessary to irradiate the temporary bonding layer 2 with radiant energy rays or the like through the support 3, the support 3 may not have light transmissivity.

[0058] The columnar structure 22 can be, for example, fine and flexible fibers. Each of the plurality of columnar structures 22 has a tip 23 facing away from the support 3. The tip 23 of the columnar structure 22 shown in FIG. 1 has a wide shape that flares upward. The fine fibers are, for example, those obtained by stretching a resin material into a thin cylindrical shape. As the stretching method, injection molding, extrusion molding, etc. can be used. Another method for obtaining fine fibers is to form a cylindrical mold on an Si substrate by dry etching and pour a resin material into the formed cylindrical mold to form cylindrical resin, that is, fine fibers. The method for forming the fine fibers is not limited to the above method. In addition, the material of the microfibers is preferably a resin material, but it may also be made of carbon fibers, glass fibers or other composite materials, and any material can be used as long as heat resistance, chemical resistance, flexibility, etc. are exhibited.

[0059] The columnar structure 22 can be formed of, for example, a resin. Preferred resins include epoxy resins, acrylic resins, silicone resins, polyesters, polyimide resins, polyamide resins, phenolic resins, fluororesins, polyurethanes, polycarbonates, polystyrenes, rubbers such as SBR and NBR, and the like.

[0060] In particular, it is preferable that the columnar structure 22 is formed of a thermosetting resin. The columnar structure 22 formed of a thermosetting resin has high process compatibility with processes such as TSV formation and backside wiring process of the wafer. Specifically, it has excellent resistance to vacuum processes such as CVD (chemical vapor deposition) and wafer thermal processes, and can further improve the productivity of thin device wafers.

[0061] For example, the columnar structure 22 formed of a silicone-modified polyimide can exhibit flexibility, and in addition, has a polyimide skeleton in the material and can exhibit heat resistance of about 300 °C or higher.

[0062] On the other hand, when the wafer and the support are bonded together with an adhesive that thermally decomposes at about 200 °C in Patent Document 2, they will have no resistance to process temperatures above the thermal decomposition temperature in the TSV formation and rewiring processes.

[0063] The plurality of columnar structures 22 may be formed directly on the support 3, but may be supported on the base portion 24, for example, as shown in FIG. 1. That is, in the temporary bonding laminate 20 according to the embodiment shown in FIG. 1, the dry adhesive fiber structure 2 includes a base portion 24 formed on the support 3 and a plurality of columnar structures 22 supported on the base portion 24. The base portion 24 may be formed of the same material as the material of the plurality of columnar structures 22 or may be formed of a different material.

[0064] As shown in, for example, FIG. 1, it is preferable that the plurality of columnar structures 22 are arranged regularly, for example, on the surface of the support 3. Further, as shown in, for example, FIG. 2, the plurality of columnar structures 22 can be formed on the support substrate 3 at a certain pitch that can avoid the electrode structure (circuit) 13 provided on the first main surface 11 side of the wafer 10 (the wafer that will become the device wafer), which is the object of temporary adhesion, in a planned manner, so that more stable temporary adhesion can be performed. That is, the plurality of columnar structures 22 may be arranged in a pattern opposite to the device pattern formed on the first main surface 11 of the wafer 10.

[0065] It is preferable that the plurality of columnar structures 22 are regularly and densely arranged on the support 3. With such an arrangement, more stable temporary adhesion can be performed. The plurality of columnar structures 22 are 2 100 pieces / mm or more 2 and 5000 pieces / mm or less, preferably 250 pieces / mm 2 or more and 1500 pieces / mm 2 or less, and are preferably formed at a density of.

[0066] Furthermore, the plurality of columnar structures 22 can be in contact with the surface of the first main surface 11 of the wafer 10 so as to follow the surface shape of this first main surface. Therefore, for example, when the first main surface 11 of the wafer 10 has concave portions 11a and convex portions 11b as shown in FIG. 2, that is, when the wafer 10 is a high-step substrate, the plurality of columnar structures 22 can perform stable temporary adhesion to the first main surface 11 of the wafer 10.

[0067] The shape of each of the plurality of columnar structures 22 can be used without particular limitation as long as it is columnar, and can be, for example, either a cylinder or a prism. As shown in FIG. 1, it is preferable that the tip 23 of the columnar structure 22 has a wide shape (spatula shape) because the adsorption force is further increased. The ratio of the cross-sectional area of the tip 23 to the main part 25 of the columnar structure 22 is preferably 1:1 to 1:2. That is, when the columnar structure has the tip 23 in contact with the wafer at the upper part, it is preferable that the upper part is wider than the lower part. The tip 23 of the columnar structure 22 may have a structure like a suction cup.

[0068] In addition, each of the columnar structures 22 can have a height of, for example, 1 μm to 1 mm, preferably a columnar structure with a height of 10 μm to 500 μm. Further, each of the columnar structures 22 can have a bottom surface with a diameter of, for example, 10 nm to 100 μm, preferably a bottom surface with a diameter of 1000 nm to 20 μm. On the other hand, each tip 23 of the columnar structures 22 can have a diameter of, for example, 20 nm to 200 μm.

[0069] The temporary bonding laminate 20 of the present invention can control the temporary bonding force with the wafer to be temporarily bonded. Specifically, for example, the temporary bonding force between the support substrate 3 and the wafer can be defined by the size of the diameter of the tip 23 of the columnar structure 22, the number of columnar structures 22 per unit area, and the diameter of the main part 25 of the columnar structure 22.

[0070] After the support substrate 3 and the wafer are temporarily bonded, in the process of forming TSVs or rewiring, handling in a process device, share stress in a CMP process, etc. are applied, so a temporary bonding force to resist this stress is required between the support substrate 3 and the wafer. On the other hand, since the support substrate 3 is finally peeled off, it is necessary to avoid applying an excessive temporary bonding force. The temporary bonding laminate 20 of the present invention can control the temporary bonding force with the wafer 10 to be temporarily bonded, so it is sufficient to withstand the stress during processing, while expressing a temporary bonding force that can be easily peeled off finally.

[0071] Preferably, the 180° peel-off force of the temporary bonding laminate 20 with a polyimide tape test piece having a width of, for example, 25 mm on the temporary bonding layer 2 is 2 gf or more and 50 gf or less. This is because, for a temporary bonding laminate 20 having such a peel-off force, for example, there is no risk of wafer displacement during wafer grinding, and peeling is easy.

[0072] Preferably, the temporary bonding laminate 20 further includes a guard ring 4 surrounding the dry adhesive fiber structure 21 formed on the support 3, as shown in FIG. 3, for example.

[0073] In the bonding surface between the wafer temporarily bonded via the temporary bonding layer 2 and the support 3, since the temporary bonding layer is a dry adhesive fiber structure, gaps will occur. After bonding the support 3 and the wafer, the wafer is often subjected to wet processes such as etching of the resist stripping metal and cleaning of the device wafer. However, it may be a problem that liquid intrudes into the aforementioned gaps. By installing the guard ring 4 on the support 3, it is possible to prevent the processing liquid from intruding into the gaps.

[0074] The planar shape of the support 3 is not particularly limited, and it may be the same planar shape as the temporary bonding layer 2 or may be a planar shape larger than the temporary bonding layer 2. When providing a circular guard ring 4, the planar shape of the support 3 may be the same planar shape as the outer peripheral shape of the guard ring 4 surrounding the dry adhesive fiber structure 21 of the temporary bonding layer 2, or may be a planar shape larger than the outer peripheral shape of the guard ring 4 as shown in FIG. 3. So far, the temporary bonding laminate 20 has been taken as an example of a circular shape with a diameter of 200 mm or 300 mm, for example. However, the temporary bonding laminate 20 may have a square or rectangular panel shape.

[0075] The ratio of the area where the columnar structure 22 is formed to the area of the support 3 is preferably 0.02% to 50%, and more preferably 1% to 25%.

[0076] [Laminated body for device wafer processing] The laminated body for device wafer processing of the present invention includes the temporary bonding laminated body of the present invention and a wafer having a first main surface including a circuit and a second main surface to be processed on the side opposite to the first main surface, and the first main surface is temporarily bonded to the support via the temporary bonding layer on the support.

[0077] The laminate for device wafer processing of the present invention includes the temporary adhesive laminate of the present invention described above. Therefore, the laminate for device wafer processing of the present invention can prevent the wafer from separating from the support during the processing of the second main surface of the wafer by temporary adhesion with a temporary adhesion layer including a dry adhesive fiber structure having a plurality of columnar structures, and after processing, the wafer can be easily peeled from the support without using an expensive device. Further, as described above, after processing, the temporary adhesion layer can be repeatedly used for other temporary adhesions. Therefore, by using the laminate for device wafer processing of the present invention, for example, a thin device wafer can be manufactured with high productivity and low cost.

[0078] Next, with reference to FIG. 4, the laminate for device wafer processing of the present invention will be specifically described.

[0079] The laminate 1 for device wafer processing shown in FIG. 4 includes a temporary adhesive laminate 20 and a wafer 10.

[0080] The temporary adhesive laminate 20 includes a support 3 and a temporary adhesion layer 2 formed on the support 3, which are described with reference to FIGS. 1 and 2. Further, the temporary adhesion layer 2 includes a dry adhesive fiber structure 21 having a plurality of columnar structures 22 shown in FIG. 1.

[0081] The wafer 10 has the structure shown in FIG. 2. That is, the wafer 10 has a first main surface 11 including a circuit 13 and a second main surface 12 to be processed on the side opposite to the first main surface 11. The first main surface 11 includes a concave portion 11a and a convex portion 11b. The first main surface 11 of the wafer 10 can be called a circuit formation surface. The second main surface 12 of the wafer 10 can be called a non-circuit formation surface.

[0082] The wafer 10 to which the present invention can be applied is usually a semiconductor wafer. Examples of the semiconductor wafer include not only silicon wafers but also germanium wafers, gallium-arsenic wafers, gallium-phosphorus wafers, gallium-arsenic-aluminum wafers, and the like. The thickness of the wafer is not particularly limited, but is typically 600 to 800 μm, more typically 625 to 775 μm.

[0083] In the laminate 1 for device wafer processing shown in FIG. 4, as shown in FIG. 2, the first main surface 11 of the wafer 10 is temporarily adhered to the support 3 via the temporary adhesive layer 2 on the support 3. In the case of the laminate 1 for device wafer processing of the present invention, even if the high-step substrate having the concave portion 11a and / or the convex portion 11b as shown in FIG. 2 is provided on the first main surface 11 of the wafer 10, the tips 23 of the plurality of columnar structures 22 can follow the surface of the first main surface 11. Therefore, as shown in FIG. 4, the second main surface 12 of the wafer 10 can be temporarily adhered to the support 3 in a state substantially parallel to the support 3. Therefore, the laminate 1 for device wafer processing of the present invention can exhibit excellent process compatibility with respect to TSV formation and the wafer backside wiring process.

[0084] [Temporary Adhesion Method] The temporary adhesion method of the present invention is a method of temporarily adhering a wafer having a first main surface including a circuit and a second main surface to be processed on the opposite side of the first main surface to a support via a temporary adhesive layer, and performing temporary adhesion between the first main surface of the wafer and the support via a temporary adhesive layer including a dry adhesive fiber structure having a plurality of columnar structures.

[0085] The temporary adhesion method of the present invention can be implemented, for example, using the temporary adhesion laminate of the present invention described above.

[0086] As described above, the temporary adhesion between the first main surface of the wafer and the support via the temporary adhesive layer including the dry adhesive fiber structure having a plurality of columnar structures can provide a temporary adhesion with sufficient strength to prevent the wafer from separating from the support during processing such as thinning processing, electrode formation, metal wiring formation, and protective film formation on the second main surface of the wafer. On the other hand, this temporary adhesion can easily peel the wafer from the support after processing without using an expensive device.

[0087] In addition, the temporary adhesive layer including the dry adhesive fiber structure having a plurality of columnar structures can be reused in other temporary adhesions even after the temporary adhesion is released once.

[0088] Thus, according to the temporary adhesion method of the present invention, sufficient strength temporary adhesion between the wafer and the support and easy peeling of the wafer from the support can be achieved, and the temporary adhesion and peeling can be repeated. Therefore, according to the temporary adhesion method of the present invention, for example, a thin device wafer can be manufactured with high productivity and low cost.

[0089] At the time of temporary adhesion, the temporary adhesive layer and the wafer may be bonded using a bonding device. In the bonding, preferably in the temperature range of room temperature to 100°C, more preferably room temperature to 80°C, the wafer and the temporary adhesive layer can be uniformly pressure-bonded (preferably greater than 0 to 5 MPa, more preferably 1 Pa to 1 MPa). For example, by this bonding, a wafer processed body (laminated substrate) in which the wafer is temporarily adhered to the support via the temporary adhesive layer, that is, the laminated body for device wafer processing described above can be formed. After this, no heat treatment or the like is required.

[0090] Examples of the wafer bonding device include commercially available wafer bonding devices, such as EVG520IS and 850TB of EVG and XBC300 of SUSS.

[0091] [Device Wafer Processing Method] The device wafer processing method of the present invention is characterized in that, by the temporary adhesion method of the present invention, temporary adhesion between the first main surface of the wafer and the support is performed, and the second main surface of the temporarily adhered wafer is processed.

[0092] In the device wafer processing method of the present invention, since the second main surface of the wafer is processed after performing temporary adhesion by the temporary adhesion method of the present invention, as described above, for example, a thin device wafer can be manufactured with high productivity and low cost.

[0093] Also, as described above, the temporary adhesion layer including the dry adhesive fiber structure having a plurality of columnar structures can be reused for other temporary adhesions even after the temporary adhesion is released once. That is, in the present invention, after processing the second main surface of one wafer, the temporary adhesion by the temporary adhesion layer is released, and then the temporary adhesion layer can be repeatedly used for other temporary adhesions.

[0094] In the above-mentioned other temporary adhesion, a silicon wafer different from the processed wafer may be temporarily adhered as a support, or a substrate other than the silicon wafer may be temporarily adhered. That is, in the present invention, after processing the second main surface of the wafer, the temporary adhesion by the temporary adhesion layer is released, and then a substrate different from the processed wafer can be temporarily adhered to the support via the temporary adhesion layer under the same bonding conditions as described above. Examples of supports other than silicon wafers include metal substrates, glass substrates, and quartz substrates. Also, the support may have a square or rectangular panel shape. The substrate temporarily adhered on the support is not limited, such as silicon, glass, metal, resin, etc.

[0095] Next, a specific example of the device wafer processing method of the present invention will be described. An example of the device wafer processing method of the present invention has the following steps (a) to (d).

[0096] [Step (a)] Step (a) is a step of temporarily adhering a wafer having a first main surface (circuit formation surface; front surface) including a circuit and a second main surface (non-circuit formation surface; back surface) to be processed on the opposite side of the first main surface to a support via a temporary adhesion layer. That is, step (a) is a step of temporarily adhering the first main surface of the wafer to the support by the temporary adhesion method of the present invention.

[0097] [Step (b)] Next, a step of grinding or polishing the second main surface (non-circuit forming surface) of the wafer temporarily adhered to the support, that is, a step of grinding the back surface side of the device wafer laminate obtained by bonding to reduce the thickness of the wafer is carried out (step (b)). There is no particular limitation on the method of grinding the second main surface of the wafer, and a known grinding method is adopted. It is preferable to perform grinding while cooling the wafer and the grindstone (such as diamond) with water. Examples of the device for grinding the second main surface of the wafer include DAG-810 (trade name) manufactured by DISCO Corporation. Also, the second main surface of the wafer may be polished by CMP.

[0098] The thickness of the thin wafer obtained by the manufacturing method of the present invention is typically 5 to 300 μm, more typically 10 to 100 μm.

[0099] [Step (c)] Next, it is a step (c) of further processing the wafer processed body with the second main surface ground, that is, the second main surface of the wafer thinned by back grinding. This step (c) includes various processes used at the wafer level. Examples include electrode formation, metal wiring formation, protective film formation, etc. More specifically, metal sputtering for forming electrodes, etc., wet etching for etching the metal sputtering layer, application of resist for masking metal wiring formation, exposure, and pattern formation by development, resist stripping, dry etching, formation of metal plating, silicon etching for TSV formation, formation of an oxide film on the silicon surface, etc., are examples of conventionally known processes.

[0100] [Step (d)] Next, it is a step of peeling the wafer processed in the above steps from the support, that is, a step of peeling the wafer from the support after performing various processes on the thinned wafer and before dicing. In other words, this step (d) is a step of releasing the temporary adhesion by the temporary adhesion layer.

[0101] This peeling step is generally carried out under relatively low temperature conditions ranging from room temperature to about 60°C. As specific methods, for example, there are methods of horizontally fixing one of the wafers or the support of the laminate for device wafer processing and lifting the other at a certain angle from the horizontal direction, a method of attaching a protective film to the ground surface of the ground wafer and peeling the wafer and the protective film from the support in a peel method, and a method of lifting and peeling a part of the wafer with tweezers, etc. The present invention is applicable to any of these peeling methods. Of course, it is not limited to the above methods.

[0102] By releasing (peeling) the temporary adhesion by the temporary adhesion layer, a device wafer having a first main surface including a circuit and a second main surface processed on the side opposite to this first main surface can be obtained.

[0103] Also, in the method for processing a device wafer of the present invention, after peeling the device wafer from the support, it is not necessary to clean both the support surface and the device wafer surface.

[0104] [Other steps] After step (d), the temporary adhesion layer can be repeatedly used in other temporary adhesions. The object of other temporary adhesions can be, for example, a substrate other than a wafer. As a specific example, when laminating another substrate such as a glass substrate or a quartz substrate on the processed wafer, temporary adhesion by the temporary adhesion layer can be used.

[0105] Alternatively, after step (d), in order to process a further wafer different from the processed wafer, the first main surface on the side opposite to the second main surface to be processed of the further wafer can be temporarily adhered to the support via the temporary adhesion layer.

[0106] Since the temporary adhesion layer used in the present invention does not require cleaning after release of the temporary adhesion, it can be efficiently repeatedly used in further temporary adhesions.

[0107] [Method for manufacturing a dry adhesive fiber structure] Here, an example of a method for manufacturing a dry-adhesive fiber structure of a temporary adhesive layer used in the present invention will be described. However, the method for manufacturing a dry-adhesive fiber structure of a temporary adhesive layer used in the present invention is not limited to the following method.

[0108] (First example) The first example is a method of transferring a plurality of columnar structures onto the surface of a support made of silicon, glass, or the like.

[0109] Specifically, for example, a cylindrical mold can be formed on a Si substrate by dry etching, and a resin material can be poured into the formed cylindrical mold to form a cylindrical resin, that is, fine fibers. The cylindrical resin molded in a circular mold in silicon is transferred onto a sheet-like base material such as PET by bringing the wide tip of the dry-adhesive fiber structure into contact with it. It can be provided by peeling off a sheet-like base material such as PET after joining the other tip of the transferred dry-adhesive fiber structure on PET to the support.

[0110] At that time, for the joining to the support, for example, the other tip is joined using a high-melting-point solder. Alternatively, after treating the surface of the support by silane coupling treatment, anodization, chemical surface roughening, etc., a fine and flexible columnar structure is transferred onto the support surface while applying heat and pressure, enabling a strong bond with the support.

[0111] (Second example) As another method of forming a dry-adhesive fiber structure on the surface of a support made of silicon, glass, or the like, for example, by injection molding, a thin film and fine columnar structures can be molded together.

[0112] After that, a composite of the support and a temporary adhesive layer formed on the support can be provided by bonding a film material containing fine columnar structures to the support.

[0113] (Third example) It is also possible to obtain a structure having a columnar structure on the surface by pouring a desired resin into a resin having porosity and performing shaping processing.

[0114] (Fourth example) In addition, a dry adhesive fiber structure having a plurality of columnar structures can also be obtained by an imprint method using a mold having microscale or nanoscale irregularities, as described in, for example, Non-Patent Document 2.

[0115] In addition, as the fine and flexible columnar structure having a wide tip shown above, a flexible columnar structure in which not only one tip of the columnar structure but both ends have a wide structure may be used. In that case, after thinning the device wafer after bonding, the support is peeled off. Naturally, there will be a surface that wants to be peeled off and a surface that does not want to be peeled off. In this case, the adsorption force of the entire dry adhesive fiber structure on the surface to be peeled off may be made weaker than the adsorption force of the entire dry adhesive fiber structure on the surface that does not want to be peeled off. The strength of the adsorption force can be controlled as described above.

Example

[0116] Hereinafter, the present invention will be specifically described using examples, but the present invention is not limited thereto.

[0117] (Example 1) A 200 mm diameter silicon wafer (thickness: 725 μm, a wafer to be a device wafer) having copper posts (electrode structures) with a height of 10 μm and a diameter of 40 μm formed on the entire surface of the first main surface, which is one of the main surfaces, was used as an object for temporary bonding.

[0118] First, in order to temporarily bond by bringing the columnar structure of the dry adhesive fiber structure into contact with the region other than the electrode structure on the first main surface of the above wafer, a glass substrate support with a diameter of 200 mm (thickness: 500 μm) having a silane coupling material spin-coated on the entire surface was prepared.

[0119] As preparation for the dry-adhesive fiber structure formed on the support substrate, a photoresist film was formed on the surface of a 300-mm diameter silicon substrate with a thickness of 725 μm, and a pattern for forming cylindrical mold holes in the silicon substrate was formed through a mask by a conventional method. Using a resist pattern with a selectivity to silicon, cylindrical pores with a diameter of 20 μm and a depth of 50 μm were formed in the silicon by dry etching using the Bosch process. After peeling off the resist for pore formation, a resist pattern was formed again to form the wide portion of the dry-adhesive fiber structure. The center position of the resist opening was made to coincide with the center of the pores in the silicon, and the opening diameter was 30 μm. Next, silicone-modified polyimide resin was poured into the pores in the silicon and the resist pattern of the opening by screen printing, and the silicon substrate was heated at 100 °C for 60 minutes. Next, after peeling off the resist pattern, a hard bake was performed at 190 °C for 4 hours to cure the silicone-modified polyimide resin.

[0120] Next, a 100-μm thick PET film with an adhesive layer on the surface was laminated on the surface of the wide portion of the dry-adhesive fiber structure formed on the silicon substrate and then pressure-bonded to transfer the dry-adhesive fiber structure onto the PET film. When the transferred dry-adhesive fiber structure was confirmed by SEM, the diameter of the columnar part was 20 μm, the diameter of the wide tip part provided regularly was 30 μm, and the height was 20 μm, which was as designed.

[0121] The density of the dry-adhesive fiber structure at this time (observed at a magnification of 2000 times by plane SEM) was about 300 pieces / mm 2 It was.

[0122] A PET film having a plurality of columnar structures was vacuum laminated onto a glass support substrate coated with a silane coupling agent under a negative pressure of 80 Pa and a temperature of 110 °C while taking alignment. The laminated support substrate was taken out into the atmosphere, the PET film on the surface was peeled off, and finally a glass support substrate with a temporary adhesive layer containing a dry-adhesive fiber structure (temporary adhesive laminate) was obtained.

[0123] On the surface of the temporary bonding laminate where the columnar structure is formed, a 200-mm-diameter silicon wafer (thickness: 725 μm) with copper posts having a height of 10 μm and a diameter of 40 μm formed on the entire surface of the first main surface, which is one of the main surfaces to be temporarily bonded, was bonded in a wafer bonding apparatus under the conditions of a chamber internal pressure of less than 10 Pa, a stage temperature of 70°C, and a load of 0.21 MPa for 60 seconds. At this time, the tips of the plurality of columnar structures of the temporary bonding layer were brought into contact with the first main surface of the wafer. Thereby, a laminate for device wafer processing was produced.

[0124] Here, a glass plate was used as a support for visually discriminating abnormalities after substrate bonding, but a silicon substrate that does not transmit light such as a wafer can also be used.

[0125] As the bonding apparatus, the wafer bonding apparatus EVG520IS manufactured by EVG was used. In addition, no problem was recognized in the quality of the bonding by visual inspection after bonding.

[0126] Next, the back surface (the second main surface opposite to the first main surface) of the silicon wafer was ground using a diamond grindstone with a grinder (manufactured by DISCO, DAG810). After grinding to a final substrate thickness of 50 μm, the presence or absence of abnormalities such as cracks and peeling was examined with an optical microscope (100 times magnification), but no abnormalities were found.

[0127] Furthermore, the processed body after back grinding the silicon wafer was introduced into a CVD apparatus, and an experiment for forming a 2-μm SiO2 film was conducted, and the presence or absence of appearance abnormalities at that time was examined. No appearance abnormalities occurred even after forming a thick oxide film. The plasma CVD apparatus used here was PD270STL (manufactured by Samco), with an output RF of 500 W, an internal pressure of 40 Pa, and the gas species being TEOS (tetraethyl orthosilicate):O2 = 20 sccm:680 sccm.

[0128] Finally, the peelability of the support substrate was confirmed. Specifically, the test was conducted as follows. A dicing tape was attached to the wafer side thinned to 50 μm of the processed device wafer after the CVD resistance test using a dicing frame, and this dicing tape surface was set on the suction plate by vacuum suction. Then, at room temperature, the glass substrate was peeled off by lifting one point of the glass with tweezers. As a result, it was possible to peel off the wafer with a thickness of 50 μm without cracking.

[0129] After peeling, that is, using the laminate for temporary bonding after release of the temporary bonding, the temporary bonding of another silicon wafer was performed (under the same conditions as above), and another laminate for processing a device wafer was produced. Before the re-temporary bonding, the temporary bonding layer was not washed. Then, the back grinding, CVD resistance test, and peel test were performed on this another laminate for processing a device wafer in the same manner as above, but no abnormalities or cracks were observed.

[0130] Thus, in Example 1, while sufficient temporary bonding strength to withstand processes such as back grinding and CVD could be achieved, the wafer could be easily peeled off from the support after processing. Also, in Example 1, after release of the temporary bonding by the temporary bonding layer, the temporary bonding layer could be used again without washing.

[0131] (Example 2) Next, the application of the chip-first process to the fan-out panel level package was examined.

[0132] A device structure in which a resin substrate (90 mm × 90 mm, thickness 500 μm) has bumps (electrode structures) made of a low melting point metal with a diameter of 15 μm and a height of 15 μm formed on the entire surface of the first main surface, which is one of the main surfaces, and aluminum pads with a size of 10 μm square are formed on the entire surface of the second main surface, which is the other surface, and the first main surface and the second main surface are connected by electrodes passing through the resin substrate was used as the object of temporary bonding.

[0133] As the support substrate for temporarily bonding the resin substrate, a glass substrate manufactured by AGC with a size of 300 mm × 100 mm and a thickness of 700 μm was used.

[0134] As preparation for forming a dry adhesive fiber structure on a support substrate, a photoresist film was formed on the surface of a 300-mm-diameter silicon substrate with a thickness of 725 μm, and a pattern for forming cylindrical mold holes in the silicon substrate through a mask was formed by a conventional method. Using a resist pattern with a selectivity to silicon, cylindrical pores with a diameter of 20 μm and a depth of 50 μm were formed in the silicon by dry etching using the Bosch process. After peeling off the resist for pore formation, a resist pattern was formed again to form the wide portion of the dry adhesive fiber structure. The center position of the resist opening coincided with the center of the pores in the silicon, the opening diameter was 30 μm, and the resist thickness was 3 μm. Next, a fluororesin was poured into the pores in the silicon and the resist pattern of the opening by screen printing, and the silicon substrate was heated at 100 °C for 60 minutes. Next, after peeling off the resist pattern, a hard bake was performed at 150 °C for 1 hour to cure the fluororesin.

[0135] Next, a 100-μm-thick PET film with an adhesive layer on the surface was laminated on the surface of the wide portion of the dry adhesive fiber structure formed on the silicon substrate and then pressure-bonded to transfer the dry adhesive fiber structure onto the PET film. When the transferred dry adhesive fiber structure was confirmed by SEM, the diameter and height of the columnar portion and the wide portion were as designed and the same as in Example 1. This operation was repeated, and finally, the dry adhesive fiber structure was transferred onto the entire surface of a 300-mm × 100-mm PET film. The density of the dry adhesive fiber structure at this time was about 300 pieces / mm 2 at that time.

[0136] Next, a silane coupling material was slot-coated on the entire surface of a 300-mm × 100-mm glass support substrate and dried. Further, a PET film having a columnar structure on the entire surface was vacuum laminated on the glass support substrate coated with the silane coupling agent under a negative pressure of 80 Pa and a temperature of 110 °C while taking alignment. The laminated support substrate was taken out into the atmosphere, the PET film on the surface was peeled off, and finally, a glass support substrate with a temporary adhesive layer containing a dry adhesive fiber structure (temporary adhesive laminate) was obtained.

[0137] On the surface of the temporary adhesive laminate where the columnar structure is formed, there is a resin substrate (90 mm × 90 mm, thickness 500 microns) to be temporarily adhered. On the first main surface, which is one of the main surfaces, bumps (electrode structures) made of a low-melting metal with a diameter of 15 μm and a height of 15 μm are formed over the entire surface. On the second main surface, which is the other surface, aluminum pads with a size of 30 microns square are formed over the entire surface. The first main surface and the second main surface are connected by electrodes passing through the resin substrate. In a substrate bonding apparatus, bonding was performed under the conditions of a stage temperature of 70 °C, a load of 0.21 MPa, and for 60 seconds. At this time, the tips of the plurality of columnar structures of the temporary adhesive layer were made to contact the first main surface of the wafer while avoiding the bump structure. A total of three resin substrates were mounted on this glass support substrate with the temporary adhesive layer (completion of the laminate for device wafer processing).

[0138] Next, the laminate for device processing using this glass as a support was sealed with a molding material using a compression apparatus. For the sealing, a film molding material SINR-DF5770 manufactured by Shin-Etsu Chemical Co., Ltd. was used, and the film thickness on the device was set to 100 microns.

[0139] Next, using a grinder (manufactured by DISCO, DFG8020) and a grinding stone, the molding material was ground until finally the aluminum pads on the second main surface were exposed. The surface of the aluminum pads after grinding was examined for abnormalities such as cracks and peeling with an optical microscope (100 times magnification), but no abnormalities were found.

[0140] Furthermore, on the plane where the aluminum pads were exposed, a photosensitive film material SINR-DF3170SP (manufactured by Shin-Etsu Chemical) with a thickness of 50 microns was laminated with a vacuum laminator in the same manner as the mold film. The lamination conditions were 100 °C and 80 Pa. In order to open the aluminum pad portion on the first main surface, photolithography was performed by a conventional method using a mask. The process conditions were pre-baking at 100 °C for 300 seconds, exposure with i-line, and an exposure dose of 1100 mJ / cm 2After exposure, it was heated at 130 °C for 300 seconds. By developing with PEGMEA, an opening pattern with a diameter of 20 microns was obtained on the aluminum pad.

[0141] Finally, after a series of processes on the glass support, in order to cut the mold layer with a dicing device and separate it into three original devices, singulation was performed. The singulated devices could be easily peeled off from the temporary adhesive layer containing the dry adhesive fiber structure.

[0142] Note that the present invention is not limited to the above embodiments. The above embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Claims

1. A method for using a temporary adhesive repeatedly for temporarily adhering a wafer to a support via a temporary adhesive layer in order to thin the wafer, comprising: As the temporary adhesive, The support; The temporary adhesive layer formed on the support; Including, The temporary adhesive layer includes a dry adhesive fiber structure having a plurality of columnar structures each having a divergent tip, The plurality of columnar structures are regularly and densely arranged on the support, A method for using a temporary adhesive, characterized in that the plurality of columnar structures are formed from a material selected from the group consisting of silicone resin, polyester, polyimide resin, polyamide resin, phenolic resin, fluororesin, polycarbonate, polystyrene, SBR, and NBR.

2. 2. The method for using the temporary adhesive according to claim 1, wherein the plurality of columnar structures are made of a thermosetting resin.

3. 3. The method for using the temporary adhesive according to claim 1, wherein the plurality of columnar structures are made of silicone modified polyimide.

4. The method for using the temporary adhesive described in any one of claims 1 to 3, characterized in that the temporary adhesive further includes a guard ring formed on the support and surrounding the dry adhesive fiber structure.

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